Collision Avoidance at Night13-515-2 When direct controlof the rotor head was perfected, the jump...

ix

Collision Avoidance at Night............................13-5Approach and Landing .....................................13-5

Chapter 14—Aeronautical Decision MakingOrigins of ADM Training......................................14-2The Decision-Making Process ..............................14-3

Defining the Problem........................................14-3Choosing a Course of Action............................14-3Implementing the Decision and Evaluating the Outcome ...................................14-3

Risk Management..................................................14-4Assessing Risk ..................................................14-4

Factors Affecting Decision Making ......................14-5Pilot Self-Assessment .......................................14-5Recognizing Hazardous Attitudes ....................14-5Stress management ...........................................14-6Use of Resources ..............................................14-6

Internal Resources ........................................14-7External Resources.......................................14-7

Workload Management.....................................14-7Situational Awareness .......................................14-8

Obstacles to Maintaining Situational Awareness ..................................14-8Operational Pitfalls.......................................14-8

GYROPLANEChapter 15—Introduction to the GyroplaneTypes of Gyroplanes..............................................15-1Components...........................................................15-2

Airframe............................................................15-2Powerplant ........................................................15-2Rotor System ....................................................15-2Tail Surfaces .....................................................15-2Landing Gear ....................................................15-3Wings ................................................................15-3

Chapter 16—Aerodynamics of the GyroplaneAutorotation...........................................................16-1

Vertical Autorotation.........................................16-1Rotor Disc Regions...........................................16-2Autorotation in Forward Flight ........................16-2

Reverse Flow................................................16-3Retreating Blade Stall ..................................16-3

Rotor Force............................................................16-3Rotor Lift ..........................................................16-4Rotor Drag ........................................................16-4

Thrust.....................................................................16-4Stability .................................................................16-5

Horizontal Stabilizer .........................................16-5Fuselage Drag (Center of Pressure)..................16-5Pitch Inertia.......................................................16-5

Propeller Thrust Line........................................16-5Rotor Force .......................................................16-6Trimmed Condition...........................................16-6

Chapter 17—Gyroplane Flight ControlsCyclic Control .......................................................17-1Throttle ..................................................................17-1Rudder ...................................................................17-2Horizontal Tail Surfaces........................................17-2Collective Control .................................................17-2

Chapter 18—Gyroplane SystemsPropulsion Systems ...............................................18-1Rotor Systems .......................................................18-1

Semirigid Rotor System....................................18-1Fully Articulated Rotor System ........................18-1

Prerotator ...............................................................18-2Mechanical Prerotator.......................................18-2Hydraulic Prerotator .........................................18-2Electric Prerotator .............................................18-3Tip Jets ..............................................................18-3

Instrumentation......................................................18-3Engine Instruments ...........................................18-3Rotor Tachometer .............................................18-3Slip/Skid Indicator ............................................18-4Airspeed Indicator ............................................18-4Altimeter ...........................................................18-4IFR Flight Instrumentation ...............................18-4

Ground Handling...................................................18-4

Chapter 19—Rotorcraft Flight Manual(Gyroplane)

Using the Flight Manual........................................19-1Weight and Balance Section .............................19-1

Sample Problem ...........................................19-1Performance Section .........................................19-2

Sample Problem ...........................................19-2Height/Velocity Diagram .............................19-3

Emergency Section ...........................................19-3Hang Test...............................................................19-4

Chapter 20—Flight OperationsPreflight .................................................................20-1

Cockpit Management........................................20-1Engine Starting ......................................................20-1Taxiing...................................................................20-1

Blade Flap.........................................................20-1Before Takeoff.......................................................20-2

Prerotation.........................................................20-2Takeoff...................................................................20-3

Normal Takeoff .................................................20-3Crosswind Takeoff ............................................20-4Common Errors for Normal and Crosswind Takeoffs ..........................................20-4Short-Field Takeoff ...........................................20-4

x

Common Errors ............................................20-4High-Altitude Takeoff ..................................20-4

Soft-Field Takeoff .............................................20-5Common Errors ............................................20-5Jump Takeoff ................................................20-5

Basic Flight Maneuvers.........................................20-6Straight-and-Level Flight..................................20-6Climbs...............................................................20-6Descents ............................................................20-7Turns .................................................................20-7

Slips..............................................................20-7Skids .............................................................20-7

Common Errors During Basic Flight Maneuvers ..............................................20-8Steep Turns .......................................................20-8

Common Errors ............................................20-8Ground Reference Maneuvers...............................20-8

Rectangular Course...........................................20-8S-Turns............................................................20-10Turns Around a Point ......................................20-11Common Errors During Ground Reference Maneuvers ........................20-11

Flight at Slow Airspeeds .....................................20-12Common Errors ..............................................20-12

High Rate of Descent ..........................................20-12Common Errors ..............................................20-13

Landings ..............................................................20-13Normal Landing..............................................20-13Short-Field Landing........................................20-13Soft-Field Landing..........................................20-14Crosswind Landing.........................................20-14

High-Altitude Landing....................................20-14Common Errors During Landing....................20-15

Go-Around...........................................................20-15Common Errors ..............................................20-15

After Landing and Securing ................................20-15

Chapter 21—Gyroplane EmergenciesAborted Takeoff.....................................................21-1

Accelerate/Stop Distance..................................21-1Lift-off at Low Airspeed andHigh Angle of Attack ............................................21-1

Common Errors ................................................21-2Pilot-Induced Oscillation (PIO) ............................21-2Buntover (Power Pushover) ..................................21-3Ground Resonance ................................................21-3Emergency Approach and Landing.......................21-3Emergency Equipment and Survival Gear............21-4

Chapter 22—Gyroplane Aeronautical DecisionMaking

Impulsivity.............................................................22-1Invulnerability .......................................................22-1Macho....................................................................22-2Resignation............................................................22-2Anti-Authority .......................................................22-3

Glossary.................................................................G-1

Index........................................................................I-1

autorotation. The first successful example of this typeof aircraft was the British Fairy Rotodyne, certificatedto the Transport Category in 1958. During the 1960sand 1970s, the popularity of gyroplanes increased withthe certification of the McCulloch J-2 and Umbaugh.The latter becoming the Air & Space 18A.

There are several aircraft under development using thefree spinning rotor to achieve rotary wing takeoff per-formance and fixed wing cruise speeds. The gyroplaneoffers inherent safety, simplicity of operation, and out-standing short field point-to-point capability.

TYPES OF GYROPLANESBecause the free spinning rotor does not require anantitorque device, a single rotor is the predominateconfiguration. Counter-rotating blades do not offerany particular advantage. The rotor system used in agyroplane may have any number of blades, but themost popular are the two and three blade systems.Propulsion for gyroplanes may be either tractor orpusher, meaning the engine may be mounted on thefront and pull the aircraft, or in the rear, pushing itthrough the air. The powerplant itself may be eitherreciprocating or turbine. Early gyroplanes wereoften a derivative of tractor configured airplaneswith the rotor either replacing the wing or acting inconjunction with it. However, the pusher configura-tion is generally more maneuverable due to theplacement of the rudder in the propeller slipstream,and also has the advantage of better visibility for thepilot. [Figure 15-1]

15-1

January 9th, 1923, marked the first officially observedflight of an autogyro. The aircraft, designed by Juan dela Cierva, introduced rotor technology that made for-ward flight in a rotorcraft possible. Until that time,rotary-wing aircraft designers were stymied by theproblem of a rolling moment that was encounteredwhen the aircraft began to move forward. This rollingmoment was the product of airflow over the rotor disc,causing an increase in lift of the advancing blade anddecrease in lift of the retreating blade. Cierva’s success-ful design, the C.4, introduced the articulated rotor, onwhich the blades were hinged and allowed to flap. Thissolution allowed the advancing blade to move upward,decreasing angle of attack and lift, while the retreatingblade would swing downward, increasing angle ofattack and lift. The result was balanced lift across therotor disc regardless of airflow. This breakthrough wasinstrumental in the success of the modern helicopter,which was developed over 15 years later. (For moreinformation on dissymmetry of lift, refer to Chapter 3—Aerodynamics of Flight.) On April 2, 1931, the PitcairnPCA-2 autogyro was granted Type Certificate No. 410and became the first rotary wing aircraft to be certifiedin the United States. The term “autogyro” was used todescribe this type of aircraft until the FAA later desig-nated them “gyroplanes.”

By definition, the gyroplane is an aircraft that achieveslift by a free spinning rotor. Several aircraft have usedthe free spinning rotor to attain performance not avail-able in the pure helicopter. The “gyrodyne” is a hybridrotorcraft that is capable of hovering and yet cruises in

Figure 15-1. The gyroplane may have wings, be either tractor or pusher configured, and could be turbine or propeller powered.Pictured are the Pitcairn PCA-2 Autogyro (left) and the Air & Space 18A gyroplane.

15-2

When direct control of the rotor head was perfected,the jump takeoff gyroplane was developed. Under theproper conditions, these gyroplanes have the ability tolift off vertically and transition to forward flight. Laterdevelopments have included retaining the direct con-trol rotor head and utilizing a wing to unload the rotor,which results in increased forward speed.

COMPONENTSAlthough gyroplanes are designed in a variety of config-urations, for the most part the basic components are thesame. The minimum components required for a func-tional gyroplane are an airframe, a powerplant, a rotorsystem, tail surfaces, and landing gear. [Figure 15-2] Anoptional component is the wing, which is incorporatedinto some designs for specific performance objectives.

AIRFRAMEThe airframe provides the structure to which all othercomponents are attached. Airframes may be weldedtube, sheet metal, composite, or simply tubes boltedtogether. A combination of construction methods mayalso be employed. The airframes with the greateststrength-to-weight ratios are a carbon fiber material or

Powerplant

Rotor

Airframe

Landing Gear

Tail Surfaces

Direct Control—The capacity forthe pilot to maneuver the aircraftby tilting the rotor disc and, onsome gyroplanes, affect changes inpitch to the rotor blades. Theseequate to cyclic and collective con-trol, which were not available inearlier autogyros.

Unload—To reduce the compo-nent of weight supported by therotor system.

Prerotate—Spinning a gyroplanerotor to sufficient r.p.m. prior toflight.

the welded tube structure, which has been in use for anumber of years.

POWERPLANTThe powerplant provides the thrust necessary for forwardflight, and is independent of the rotor system while inflight. While on the ground, the engine may be used asa source of power to prerotate the rotor system. Overthe many years of gyroplane development, a widevariety of engine types have been adapted to the gyro-plane. Automotive, marine, ATV, and certificated aircraft engines have all been used in various gyroplane designs. Certificated gyroplanes arerequired to use FAA certificated engines. The cost of anew certificated aircraft engine is greater than the costof nearly any other new engine. This added cost is theprimary reason other types of engines are selected foruse in amateur built gyroplanes.

ROTOR SYSTEMThe rotor system provides lift and control for the gyro-plane. The fully articulated and semi-rigid teeteringrotor systems are the most common. These areexplained in-depth in Chapter 5—Main Rotor System.The teeter blade with hub tilt control is most commonin homebuilt gyroplanes. This system may also employa collective control to change the pitch of the rotorblades. With sufficient blade inertia and collectivepitch change, jump takeoffs can be accomplished.

TAIL SURFACESThe tail surfaces provide stability and control in the pitchand yaw axes. These tail surfaces are similar to an air-plane empennage and may be comprised of a fin andrudder, stabilizer and elevator. An aft mounted ductenclosing the propeller and rudder has also been used.Many gyroplanes do not incorporate a horizontal tail surface.

On some gyroplanes, especially those with an enclosedcockpit, the yaw stability is marginal due to the largefuselage side area located ahead of the center of grav-ity. The additional vertical tail surface necessary tocompensate for this instability is difficult to achieve asthe confines of the rotor tilt and high landing pitch atti-tude limits the available area. Some gyroplane designsincorporate multiple vertical stabilizers and rudders toadd additional yaw stability.

Figure 15-2. Gyroplanes typically consist of five major com-ponents. A sixth, the wing, is utilized on some designs.

15-3

LANDING GEARThe landing gear provides the mobility while on theground and may be either conventional or tricycle.Conventional gear consists of two main wheels, and oneunder the tail. The tricycle configuration also uses twomains, with the third wheel under the nose. Early auto-gyros, and several models of gyroplanes, use conven-tional gear, while most of the later gyroplanesincorporate tricycle landing gear. As with fixed wingaircraft, the gyroplane landing gear provides the groundmobility not found in most helicopters.

WINGSWings may or may not comprise a component of thegyroplane. When used, they provide increased per-formance, increased storage capacity, and increasedstability. Gyroplanes are under development withwings that are capable of almost completely unload-ing the rotor system and carrying the entire weight

of the aircraft. This will allow rotary wing takeoffperformance with fixed wing cruise speeds. [Figure15-3]

Figure 15-3. The CarterCopter uses wings to enhanceperformance.

16-1

Helicopters and gyroplanes both achieve lift throughthe use of airfoils, and, therefore, many of the basicaerodynamic principles governing the production of liftapply to both aircraft. These concepts are explained indepth in Chapter 2—General Aerodynamics, and con-stitute the foundation for discussing the aerodynamicsof a gyroplane.

AUTOROTATIONA fundamental difference between helicopters andgyroplanes is that in powered flight, a gyroplane rotorsystem operates in autorotation. This means the rotorspins freely as a result of air flowing up through theblades, rather than using engine power to turn theblades and draw air from above. [Figure 16-1] Forcesare created during autorotation that keep the rotorblades turning, as well as creating lift to keep the air-craft aloft. Aerodynamically, the rotor system of agyroplane in normal flight operates like a helicopterrotor during an engine-out forward autorotativedescent.

VERTICAL AUTOROTATIONDuring a vertical autorotation, two basic componentscontribute to the relative wind striking the rotor blades.[Figure 16-2] One component, the upward flow of airthrough the rotor system, remains relatively constant

for a given flight condition. The other component is therotational airflow, which is the wind velocity across theblades as they spin. This component varies signifi-cantly based upon how far from the rotor hub it ismeasured. For example, consider a rotor disc that is 25feet in diameter operating at 300 r.p.m. At a point onefoot outboard from the rotor hub, the blades are travel-ing in a circle with a circumference of 6.3 feet. Thisequates to 31.4 feet per second (f.p.s.), or a rotationalblade speed of 21 m.p.h. At the blade tips, the circum-ference of the circle increases to 78.5 feet. At the sameoperating speed of 300 r.p.m., this creates a blade tip

Direction of Flight

Relative Wind Relative Wind

Direction of Flight

Figure 16-1. Airflow through the rotor system on a gyroplane is reversed from that on a powered helicopter. This airflow is themedium through which power is transferred from the gyroplane engine to the rotor system to keep it rotating.

Resultant Relative Wind

Wind due to Blade Rotation

Upward Airflow

Figure 16-2. In a vertical autorotation, the wind from the rotation of the blade combines with the upward airflow toproduce the resultant relative wind striking the airfoil.

16-2

speed of 393 feet per second, or 267 m.p.h. The resultis a higher total relative wind, striking the blades at alower angle of attack. [Figure 16-3]

ROTOR DISC REGIONSAs with any airfoil, the lift that is created by rotorblades is perpendicular to the relative wind. Becausethe relative wind on rotor blades in autorotation shiftsfrom a high angle of attack inboard to a lower angle ofattack outboard, the lift generated has a higher forwardcomponent closer to the hub and a higher vertical com-ponent toward the blade tips. This creates distinctregions of the rotor disc that create the forces neces-sary for flight in autorotation. [Figure 16-4] Theautorotative region, or driving region, creates a totalaerodynamic force with a forward component thatexceeds all rearward drag forces and keeps the bladesspinning. The propeller region, or driven region, gen-erates a total aerodynamic force with a higher verticalcomponent that allows the gyroplane to remain aloft.Near the center of the rotor disc is a stall region wherethe rotational component of the relative wind is so lowthat the resulting angle of attack is beyond the stalllimit of the airfoil. The stall region creates drag againstthe direction of rotation that must be overcome by theforward acting forces generated by the driving region.

AUTOROTATION IN FORWARD FLIGHTAs discussed thus far, the aerodynamics of autorotationapply to a gyroplane in a vertical descent. Becausegyroplanes are normally operated in forward flight, thecomponent of relative wind striking the rotor blades asa result of forward speed must also be considered. Thiscomponent has no effect on the aerodynamic principlesthat cause the blades to autorotate, but causes a shift inthe zones of the rotor disc.

As a gyroplane moves forward through the air, the for-ward speed of the aircraft is effectively added to the

Resultant Relative Wind

Rotational Airflow (267 m.p.h. or 393 f.p.s.)

Upward Airflow (17 m.p.h. or 25 f.p.s.)

TIP

Rotor Speed: 300 r.p.m.

F

Resultant

Relative WindRotational Airflow

(21 m.p.h. or 31 f.p.s.)

Upward Airflow (17 m.p.h. or 25 f.p.s.)

HUB

VERTICAL AUTOROTATION

Figure 16-3. Moving outboard on the rotor blade, the rotational velocity increasingly exceeds the upward component of airflow,resulting in a higher relative wind at a lower angle of attack.

Driven Region

Driving Region

Stall

Region

Driven Region (Propeller)

Driving Region (Autorotative)

Stall Region

F

VERTICAL AUTOROTATION

Rotational Relative Wind

LiftLift

TAFTAF

Total Aerodynamic Force Aft of Axis of Rotation

Drag

Chord LineInflow Up Through Rotor Resultant

Relative Wind

Total Aerodynamic Force Forward of Axis of Rotation

Drag

Inflow

Axis of Rotation

Axis of Rotation

Axis of Rotation

(Blade is Stalled)

TAF

Drag

Inflow

Lift

Figure 16-4. The total aerodynamic force is aft of the axis ofrotation in the driven region and forward of the axis of rota-tion in the driving region. Drag is the major aerodynamicforce in the stall region. For a complete depiction of forcevectors during a vertical autorotation, refer to Chapter 3—Aerodynamics of Flight (Helicopter), Figure 3-22.

16-3

relative wind striking the advancing blade, and sub-tracted from the relative wind striking the retreatingblade. To prevent uneven lifting forces on the two sidesof the rotor disc, the advancing blade teeters up,decreasing angle of attack and lift, while the retreatingblade teeters down, increasing angle of attack and lift.(For a complete discussion on dissymmetry of lift, referto Chapter 3—Aerodynamics of Flight.) The lowerangles of attack on the advancing blade cause more ofthe blade to fall in the driven region, while higherangles of attack on the retreating blade cause more ofthe blade to be stalled. The result is a shift in the rotorregions toward the retreating side of the disc to a degreedirectly related to the forward speed of the aircraft.[Figure 16-5]

REVERSE FLOWOn a rotor system in forward flight, reverse flow occursnear the rotor hub on the retreating side of the rotordisc. This is the result of the forward speed of the air-craft exceeding the rotational speed of the rotor blades.For example, two feet outboard from the rotor hub, theblades travel in a circle with a circumference of 12.6feet. At a rotor speed of 300 r.p.m., the blade speed atthe two-foot station is 42 m.p.h. If the aircraft is beingoperated at a forward speed of 42 m.p.h., the forwardspeed of the aircraft essentially negates the rotationalvelocity on the retreating blade at the two-foot station.Moving inboard from the two-foot station on theretreating blade, the forward speed of the aircraftincreasingly exceeds the rotational velocity of theblade. This causes the airflow to actually strike thetrailing edge of the rotor blade, with velocity increas-ing toward the rotor hub. [Figure 16-6] The size of thearea that experiences reverse flow is dependent prima-

rily on the forward speed of the aircraft, with higherspeed creating a larger region of reverse flow. To somedegree, the operating speed of the rotor system also hasan effect on the size of the region, with systems operat-ing at lower r.p.m. being more susceptible to reverseflow and allowing a greater portion of the blade toexperience the effect.

RETREATING BLADE STALLThe retreating blade stall in a gyroplane differs fromthat of a helicopter in that it occurs outboard from therotor hub at the 20 to 40 percent position rather than atthe blade tip. Because the gyroplane is operating inautorotation, in forward flight there is an inherent stallregion centered inboard on the retreating blade. [Referto figure 16-5] As forward speed increases, the angle ofattack on the retreating blade increases to prevent dis-symmetry of lift and the stall region moves further outboard on the retreating blade. Because the stalledportion of the rotor disc is inboard rather than near thetip, as with a helicopter, less force is created about theaircraft center of gravity. The result is that you may feela slight increase in vibration, but you would not experi-ence a large pitch or roll tendency.

ROTOR FORCEAs with any heavier than air aircraft, the four forcesacting on the gyroplane in flight are lift, weight, thrustand drag. The gyroplane derives lift from the rotor and

Forward

Driven Region

Driving Region

Stall

Region

Retreating Side

Advancing Side

Figure 16-5. Rotor disc regions in forward autorotative flight.

Forward Flight at

42 kt

42kt

42kt

42kt

42kt

2'

Area of Reverse flow

42kt

Rotor Speed 300 r.p.m.

Figure 16-6. An area of reverse flow forms on the retreatingblade in forward flight as a result of aircraft speed exceedingblade rotational speed.

16-4

rotor blades turn, rapid changes occur on the airfoilsdepending on position, rotor speed, and aircraft speed.A change in the angle of attack of the rotor disc caneffect a rapid and substantial change in total rotor drag.

Rotor drag can be divided into components of induceddrag and profile drag. The induced drag is a product oflift, while the profile drag is a function of rotor r.p.m.Because induced drag is a result of the rotor providinglift, profile drag can be considered the drag of the rotorwhen it is not producing lift. To visualize profile drag,consider the drag that must be overcome to prerotatethe rotor system to flight r.p.m. while the blades areproducing no lift. This can be achieved with a rotor sys-tem having a symmetrical airfoil and a pitch changecapability by setting the blades to a 0° angle of attack.A rotor system with an asymmetrical airfoil and a builtin pitch angle, which includes most amateur-builtteeter-head rotor systems, cannot be prerotated withouthaving to overcome the induced drag created as well.

THRUSTThrust in a gyroplane is defined as the component oftotal propeller force parallel to the relative wind. Aswith any force applied to an aircraft, thrust acts aroundthe center of gravity. Based upon where the thrust isapplied in relation to the aircraft center of gravity, a rel-atively small component may be perpendicular to therelative wind and can be considered to be additive tolift or weight.

In flight, the fuselage of a gyroplane essentially acts asa plumb suspended from the rotor, and as such, it is

thrust directly from the engine through a propeller.[Figure 16-7]

The force produced by the gyroplane rotor may bedivided into two components; rotor lift and rotor drag.The component of rotor force perpendicular to theflight path is rotor lift, and the component of rotor forceparallel to the flight path is rotor drag. To derive thetotal aircraft drag reaction, you must also add the dragof the fuselage to that of the rotor.

ROTOR LIFTRotor lift can most easily be visualized as the liftrequired to support the weight of the aircraft. When anairfoil produces lift, induced drag is produced. Themost efficient angle of attack for a given airfoil pro-duces the most lift for the least drag. However, the air-foil of a rotor blade does not operate at this efficientangle throughout the many changes that occur in eachrevolution. Also, the rotor system must remain in theautorotative (low) pitch range to continue turning inorder to generate lift.

Some gyroplanes use small wings for creating lift whenoperating at higher cruise speeds. The lift provided bythe wings can either supplement or entirely replacerotor lift while creating much less induced drag.

ROTOR DRAGTotal rotor drag is the summation of all the drag forcesacting on the airfoil at each blade position. Each bladeposition contributes to the total drag according to thespeed and angle of the airfoil at that position. As the

Lift

Resultant

Thrust

Resultant

Thrust

Lift

Result

ant

Drag

Rotor Drag

Fuselage Drag

Result

ant

Wei

ght

Wei

ght

Figure 16-7. Unlike a helicopter, in forward powered flight the resultant rotor force of a gyroplane acts in a rearward direction.

16-5

subject to pendular action in the same way as a heli-copter. Unlike a helicopter, however, thrust is applieddirectly to the airframe of a gyroplane rather than beingobtained through the rotor system. As a result, differentforces act on a gyroplane in flight than on a helicopter.Engine torque, for example, tends to roll the fuselagein the direction opposite propeller rotation, causing itto be deflected a few degrees out of the vertical plane.[Figure 16-8] This slight “out of vertical” condition isusually negligible and not considered relevant for mostflight operations.

STABILITYStability is designed into aircraft to reduce pilot work-load and increase safety. A stable aircraft, such as a typ-ical general aviation training airplane, requires lessattention from the pilot to maintain the desired flightattitude, and will even correct itself if disturbed by agust of wind or other outside forces. Conversely, anunstable aircraft requires constant attention to maintaincontrol of the aircraft.

Reactive Torque on Fuselage

Torque Applied to Propeller

Figure 16-8. Engine torque applied to the propeller has anequal and opposite reaction on the fuselage, deflecting it afew degrees out of the vertical plane in flight.

Pendular Action—The lateral orlongitudinal oscillation of the fuse-lage due to it being suspendedfrom the rotor system. It is similarto the action of a pendulum.Pendular action is further dis-cussed in Chapter 3—Aerodynamics of Flight.

There are several factors that contribute to the stabilityof a gyroplane. One is the location of the horizontal stabilizer. Another is the location of the fuselage dragin relation to the center of gravity. A third is the inertia moment around the pitch axis, while a fourth isthe relation of the propeller thrust line to the verticallocation of the center of gravity (CG). However, theone that is probably the most critical is the relation ofthe rotor force line to the horizontal location of the center of gravity.

HORIZONTAL STABILIZERA horizontal stabilizer helps in longitudinal stability,with its efficiency greater the further it is from the center of gravity. It is also more efficient at higher airspeeds because lift is proportional to the square ofthe airspeed. Since the speed of a gyroplane is not veryhigh, manufacturers can achieve the desired stabilityby varying the size of the horizontal stabilizer, chang-ing the distance it is from the center of gravity, or byplacing it in the propeller slipstream.

FUSELAGE DRAG(CENTER OF PRESSURE)If the location, where the fuselage drag or center ofpressure forces are concentrated, is behind the CG,the gyroplane is considered more stable. This is espe-cially true of yaw stability around the vertical axis.However, to achieve this condition, there must be asufficient vertical tail surface. In addition, the gyro-plane needs to have a balanced longitudinal center ofpressure so there is sufficient cyclic movement toprevent the nose from tucking under or lifting, aspressure builds on the frontal area of the gyroplane asairspeed increases.

PITCH INERTIAWithout changing the overall weight and center ofgravity of a gyroplane, the further weights are placedfrom the CG, the more stable the gyroplane. For exam-ple, if the pilot's seat could be moved forward from theCG, and the engine moved aft an amount, which keepsthe center of gravity in the same location, the gyroplanebecomes more stable. A tightrope walker applies thissame principle when he uses a long pole to balancehimself.

PROPELLER THRUST LINEConsidering just the propeller thrust line by itself, if thethrust line is above the center of gravity, the gyroplanehas a tendency to pitch nose down when power isapplied, and to pitch nose up when power is removed.The opposite is true when the propeller thrust line isbelow the CG. If the thrust line goes through the CG or

16-6

nearly so there is no tendency for the nose to pitch upor down. [Figure 16-9]

ROTOR FORCEBecause some gyroplanes do not have horizontal stabi-lizers, and the propeller thrust lines are different, gyro-plane manufacturers can achieve the desired stabilityby placing the center of gravity in front of or behind therotor force line. [Figure 16-10]

Suppose the CG is located behind the rotor force line inforward flight. If a gust of wind increases the angle ofattack, rotor force increases. There is also an increasein the difference between the lift produced on theadvancing and retreating blades. This increases theflapping angle and causes the rotor to pitch up. Thispitching action increases the moment around the centerof gravity, which leads to a greater increase in the angleof attack. The result is an unstable condition.

If the CG is in front of the rotor force line, a gust ofwind, which increases the angle of attack, causes therotor disc to react the same way, but now the increasein rotor force and blade flapping decreases themoment. This tends to decrease the angle of attack, andcreates a stable condition.

TRIMMED CONDITIONAs was stated earlier, manufacturers use a combinationof the various stability factors to achieve a trimmedgyroplane. For example, if you have a gyroplane wherethe CG is below the propeller thrust line, the propellerthrust gives your aircraft a nose down pitching momentwhen power is applied. To compensate for this pitchingmoment, the CG, on this type of gyroplane, is usuallylocated behind the rotor force line. This location pro-duces a nose up pitching moment.

Conversely, if the CG is above the propeller thrust line,the CG is usually located ahead of the rotor force line.Of course, the location of fuselage drag, the pitch iner-tia, and the addition of a horizontal stabilizer can alterwhere the center of gravity is placed.

Propeller Thrust

Propeller Thrust

Center of Gravity Center of Gravity

High ProfileLow Profile

Rot

orF

orce

Rot

orF

orce

Figure 16-9. A gyroplane which has the propeller thrust line above the center of gravity is often referred to as a low profile gyro-plane. One that has the propeller thrust line below or at the CG is considered a high profile gyroplane.

Figure 16-10. If the CG is located in front of the rotor force line, the gyroplane is more stable than if the CG is located behind therotor force line.

Blade Flapping—The upward or downward movement of the rotor-blades during rotation.

17-1

Due to rudimentary flight control systems, early gyroplanessuffered from limited maneuverability. As technologyimproved, greater control of the rotor system and moreeffective control surfaces were developed. The moderngyroplane, while continuing to maintain an element ofsimplicity, now enjoys a high degree of maneuver-ability as a result of these improvements.

CYCLIC CONTROLThe cyclic control provides the means whereby you areable to tilt the rotor system to provide the desiredresults. Tilting the rotor system provides all control forclimbing, descending, and banking the gyroplane. Themost common method to transfer stick movement tothe rotor head is through push-pull tubes or flex cables.[Figure 17-1] Some gyroplanes use a direct overheadstick attachment rather than a cyclic, where a rigid con-trol is attached to the rotor hub and descends over andin front of the pilot. [Figure 17-2] Because of thenature of the direct attachment, control inputs with thissystem are reversed from those used with a cyclic.Pushing forward on the control causes the rotor disc totilt back and the gyroplane to climb, pulling back onthe control initiates a descent. Bank commands arereversed in the same way.

THROTTLEThe throttle is conventional to most powerplants, andprovides the means for you to increase or decreaseengine power and thus, thrust. Depending on how

the control is designed, control movement may ormay not be proportional to engine power. With manygyroplane throttles, 50 percent of the control travelmay equate to 80 or 90 percent of available power.This varying degree of sensitivity makes it necessary

Figure 17-1. A common method of transferring cyclic control inputs to the rotor head is through the use of push-pull tubes,located outboard of the rotor mast pictured on the right.

Figure 17-2. The direct overhead stick attachment has beenused for control of the rotor disc on some gyroplanes.

17-2

for you to become familiar with the unique throttle characteristics and engine responses for a particulargyroplane.

RUDDERThe rudder is operated by foot pedals in the cockpit and provides a means to control yaw movement of theaircraft. [Figure 17-3] On a gyroplane, this control isachieved in a manner more similar to the rudder of anairplane than to the antitorque pedals of a helicopter.The rudder is used to maintain coordinated flight, andat times may also require inputs to compensate for propeller torque. Rudder sensitivity and effectivenessare directly proportional to the velocity of airflow overthe rudder surface. Consequently, many gyroplane rudders are located in the propeller slipstream and provide excellent control while the engine is developingthrust. This type of rudder configuration, however, isless effective and requires greater deflection when theengine is idled or stopped.

HORIZONTAL TAIL SURFACESThe horizontal tail surfaces on most gyroplanes are not controllable by the pilot. These fixed surfaces, or

stabilizers, are incorporated into gyroplane designs toincrease the pitch stability of the aircraft. Some gyro-planes use very little, if any, horizontal surface. Thistranslates into less stability, but a higher degree ofmaneuverability. When used, a moveable horizontalsurface, or elevator, adds additional pitch control of theaircraft. On early tractor configured gyroplanes, theelevator served an additional function of deflecting thepropeller slipstream up and through the rotor to assistin prerotation.

COLLECTIVE CONTROLThe collective control provides a means to vary therotor blade pitch of all the blades at the same time, andis available only on more advanced gyroplanes. Whenincorporated into the rotor head design, the collectiveallows jump takeoffs when the blade inertia is suffi-cient. Also, control of in-flight rotor r.p.m. is availableto enhance cruise and landing performance. A simpletwo position collective does not allow unlimited controlof blade pitch, but instead has one position for prerotationand another position for flight. This is a performancecompromise but reduces pilot workload by simplifyingcontrol of the rotor system.

Figure 17-3. Foot pedals provide rudder control and operation is similar to that of an airplane.

18-1

rotating portion of the head to the non-rotating torquetube. The torque tube is mounted to the airframethrough attachments allowing both lateral and longitu-dinal movement. This allows the movement throughwhich control is achieved.

FULLY ARTICULATED ROTOR SYSTEM The fully articulated rotor system is found on somegyroplanes. As with helicopter-type rotor systems, thearticulated rotor system allows the manipulation of

Coning Angle—An angulardeflection of the rotor bladesupward from the rotor hub.

Undersling—A design character-istic that prevents the distancebetween the rotor mast axis andthe center of mass of each rotorblade from changing as theblades teeter. This precludesCoriolis Effect from acting on thespeed of the rotor system.Undersling is further explainedin Chapter 3—Aerodynamics ofFlight, Coriolis Effect (Law ofConservation of AngularMomentum).

Gyroplanes are available in a wide variety of designsthat range from amateur built to FAA-certificated air-craft. Similarly, the complexity of the systems inte-grated in gyroplane design cover a broad range. Toensure the airworthiness of your aircraft, it is importantthat you thoroughly understand the design and opera-tion of each system employed by your machine.

PROPULSION SYSTEMSMost of the gyroplanes flying today use a reciprocatingengine mounted in a pusher configuration that driveseither a fixed or constant speed propeller. The enginesused in amateur-built gyroplanes are normally provenpowerplants adapted from automotive or other uses.Some amateur-built gyroplanes use FAA-certificated air-craft engines and propellers. Auto engines, along withsome of the other powerplants adapted to gyroplanes,operate at a high r.p.m., which requires the use of a reduc-tion unit to lower the output to efficient propeller speeds.

Early autogyros used existing aircraft engines, whichdrove a propeller in the tractor configuration. Severalamateur-built gyroplanes still use this propulsion con-figuration, and may utilize a certificated or an uncer-tificated engine. Although not in use today, turbopropand pure jet engines could also be used for the propul-sion of a gyroplane.

ROTOR SYSTEMSSEMIRIGID ROTOR SYSTEMAny rotor system capable of autorotation may be utilizedin a gyroplane. Because of its simplicity, the most widelyused system is the semirigid, teeter-head system. Thissystem is found in most amateur-built gyroplanes.[Figure 18-1] In this system, the rotor head is mountedon a spindle, which may be tilted for control. The rotorblades are attached to a hub bar that may or may nothave adjustments for varying the blade pitch. A coningangle, determined by projections of blade weight,rotor speed, and load to be carried, is built into the hubbar. This minimizes hub bar bending moments andeliminates the need for a coning hinge, which is usedin more complex rotor systems. A tower block pro-vides the undersling and attachment to the rotor headby the teeter bolt. The rotor head is comprised of abearing block in which the bearing is mounted andonto which the tower plates are attached. The spindle(commonly, a vertically oriented bolt) attaches the

Figure 18-1. The semirigid, teeter-head system is found onmost amateur-built gyroplanes. The rotor hub bar and bladesare permitted to tilt by the teeter bolt.

Tower Plates

Hub Bar

Tower Block

Bearing Block

Teeter Bolt

Spindle Bolt

Torque Tube

Fore / Aft Pivot Bolt

Lateral Pivot Bolt

18-2

rotor blade pitch while in flight. This system is signifi-cantly more complicated than the teeter-head, as itrequires hinges that allow each rotor blade to flap,feather, and lead or lag independently. [Figure 18-2]When used, the fully articulated rotor system of a gyro-plane is very similar to those used on helicopters, whichis explained in depth in Chapter 5—Helicopter Systems,Main Rotor Systems. One major advantage of using afully articulated rotor in gyroplane design is that it usu-ally allows jump takeoff capability. Rotor characteristicsrequired for a successful jump takeoff must include amethod of collective pitch change, a blade with sufficientinertia, and a prerotation mechanism capable of approxi-mately 150 percent of rotor flight r.p.m.

Incorporating rotor blades with high inertia potential isdesirable in helicopter design and is essential for jumptakeoff gyroplanes. A rotor hub design allowing therotor speed to exceed normal flight r.p.m. by over 50 percent is not found in helicopters, and predicates arotor head design particular to the jump takeoff gyroplane, yet very similar to that of the helicopter.

PREROTATORPrior to takeoff, the gyroplane rotor must first achievea rotor speed sufficient to create the necessary lift.This is accomplished on very basic gyroplanes by ini-tially spinning the blades by hand. The aircraft is thentaxied with the rotor disc tilted aft, allowing airflowthrough the system to accelerate it to flight r.p.m.More advanced gyroplanes use a prerotator, whichprovides a mechanical means to spin the rotor. Manyprerotators are capable of only achieving a portion ofthe speed necessary for flight; the remainder isgained by taxiing or during the takeoff roll. Becauseof the wide variety of prerotation systems available,you need to become thoroughly familiar with thecharacteristics and techniques associated with yourparticular system.

MECHANICAL PREROTATORMechanical prerotators typically have clutches or beltsfor engagement, a drive train, and may use a transmis-sion to transfer engine power to the rotor. Frictiondrives and flex cables are used in conjunction with anautomotive type bendix and ring gear on many gyro-planes. [Figure 18-3]

The mechanical prerotator used on jump takeoff gyro-planes may be regarded as being similar to the helicoptermain rotor drive train, but only operates while the air-craft is firmly on the ground. Gyroplanes do not have anantitorque device like a helicopter, and ground contact isnecessary to counteract the torque forces generated bythe prerotation system. If jump takeoff capability isdesigned into a gyroplane, rotor r.p.m. prior to liftoffmust be such that rotor energy will support the air-craft through the acceleration phase of takeoff. Thiscombination of rotor system and prerotator utilizesthe transmission only while the aircraft is on theground, allowing the transmission to be disconnectedfrom both the rotor and the engine while in normalflight.

HYDRAULIC PREROTATORThe hydraulic prerotator found on gyroplanes usesengine power to drive a hydraulic pump, which in turndrives a hydraulic motor attached to an automotive typebendix and ring gear. [Figure 18-4] This system alsorequires that some type of clutch and pressure regula-tion be incorporated into the design.

Figure 18-2. The fully articulated rotor system enables thepilot to effect changes in pitch to the rotor blades, which isnecessary for jump takeoff capability.

Figure 18-3. The mechanical prerotator used by many gyro-planes uses a friction drive at the propeller hub, and a flexi-ble cable that runs from the propeller hub to the rotor mast.When engaged, the bendix spins the ring gear located on therotor hub.

18-3

ELECTRIC PREROTATORThe electric prerotator found on gyroplanes uses anautomotive type starter with a bendix and ring gearmounted at the rotor head to impart torque to the rotorsystem. [Figure 18-5] This system has the advantage ofsimplicity and ease of operation, but is dependent onhaving electrical power available. Using a “soft start”device can alleviate the problems associated with thehigh starting torque initially required to get the rotorsystem turning. This device delivers electrical pulses tothe starter for approximately 10 seconds before con-necting uninterrupted voltage.

TIP JETSJets located at the rotor blade tips have been used in sev-eral applications for prerotation, as well as for hoverflight. This system has no requirement for a transmissionor clutches. It also has the advantage of not impartingtorque to the airframe, allowing the rotor to be poweredin flight to give increased climb rates and even the abilityto hover. The major disadvantage is the noise generatedby the jets. Fortunately, tip jets may be shut down whileoperating in the autorotative gyroplane mode.

INSTRUMENTATIONThe instrumentation required for flight is generallyrelated to the complexity of the gyroplane. Some gyro-planes using air-cooled and fuel/oil-lubricated enginesmay have limited instrumentation.

ENGINE INSTRUMENTSAll but the most basic engines require monitoringinstrumentation for safe operation. Coolant tempera-ture, cylinder head temperatures, oil temperature, oilpressure, carburetor air temperature, and exhaust gastemperature are all direct indications of engine opera-tion and may be displayed. Engine power is normallyindicated by engine r.p.m., or by manifold pressure ongyroplanes with a constant speed propeller.

ROTOR TACHOMETERMost gyroplanes are equipped with a rotor r.p.m. indica-tor. Because the pilot does not normally have direct control of rotor r.p.m. in flight, this instrument is mostuseful on the takeoff roll to determine when there is suf-ficient rotor speed for liftoff. On gyroplanes notequipped with a rotor tachometer, additional pilotingskills are required to sense rotor r.p.m. prior to takeoff.

Figure 18-4. This prerotator uses belts at the propeller hub to drive a hydraulic pump, which drives a hydraulic motor on therotor mast.

Figure 18-5. The electric prerotator is simple and easy to use,but requires the availability of electrical power.

18-4

Certain gyroplane maneuvers require you to know pre-cisely the speed of the rotor system. Performing a jumptakeoff in a gyroplane with collective control is oneexample, as sufficient rotor energy must be availablefor the successful outcome of the maneuver. Whenvariable collective and a rotor tachometer are used,more efficient rotor operation may be accomplished byusing the lowest practical rotor r.p.m. [Figure 18-6]

SLIP/SKID INDICATORA yaw string attached to the nose of the aircraft and aconventional inclinometer are often used in gyroplanesto assist in maintaining coordinated flight. [Figure 18-7]

AIRSPEED INDICATORAirspeed knowledge is essential and is most easilyobtained by an airspeed indicator that is designed foraccuracy at low airspeeds. Wind speed indicatorshave been adapted to many gyroplanes. When no air-

speed indicator is used, as in some very basic amateur-built machines, you must have a very acutesense of “q” (impact air pressure against your body).

ALTIMETERFor the average pilot, it becomes increasingly difficultto judge altitude accurately when more than severalhundred feet above the ground. A conventional altime-ter may be used to provide an altitude reference whenflying at higher altitudes where human perceptiondegrades.

IFR FLIGHT INSTRUMENTATIONGyroplane flight into instrument meteorological condi-tions requires adequate flight instrumentation and navi-gational systems, just as in any aircraft. Very fewgyroplanes have been equipped for this type of operation.The majority of gyroplanes do not meet the stabilityrequirements for single-pilot IFR flight. As larger andmore advanced gyroplanes are developed, issues of IFRflight in these aircraft will have to be addressed.

GROUND HANDLINGThe gyroplane is capable of ground taxiing in a mannersimilar to that of an airplane. A steerable nose wheel,which may be combined with independent main wheelbrakes, provides the most common method of control.[Figure 18-8] The use of independent main wheelbrakes allows differential braking, or applying morebraking to one wheel than the other to achieve tightradius turns. On some gyroplanes, the steerable nosewheel is equipped with a foot-operated brake ratherthan using main wheel brakes. One limitation of thissystem is that the nose wheel normally supports only afraction of the weight of the gyroplane, which greatlyreduces braking effectiveness. Another drawback is the

Figure 18-6. A rotor tachometer can be very useful to deter-mine when rotor r.p.m. is sufficient for takeoff.

Figure 18-7. A string simply tied near the nose of the gyro-plane that can be viewed from the cockpit is often used toindicate rotation about the yaw axis. An inclinometer mayalso be used.

Figure 18-8. Depending on design, main wheel brakes can beoperated either independently or collectively. They are con-siderably more effective than nose wheel brakes.

18-5

inability to use differential braking, which increasesthe radius of turns.

The rotor blades demand special consideration duringground handling, as turning rotor blades can be a haz-ard to those nearby. Many gyroplanes have a rotor

brake that may be used to slow the rotor after landing,or to secure the blades while parked. A parked gyro-plane should never be left with unsecured blades,because even a slight change in wind could cause theblades to turn or flap.

19-1

As with most certificated aircraft manufactured afterMarch 1979, FAA-certificated gyroplanes are requiredto have an approved flight manual. The flight manualdescribes procedures and limitations that must beadhered to when operating the aircraft. Specificationfor Pilot’s Operating Handbook, published by theGeneral Aviation Manufacturers Association (GAMA),provides a recommended format that more recent gyro-plane flight manuals follow. [Figure 19-1]

This format is the same as that used by helicopters,which is explained in depth in Chapter 6—RotorcraftFlight Manual (Helicopter).

Amateur-built gyroplanes may have operating limita-tions but are not normally required to have an approvedflight manual. One exception is an exemption grantedby the FAA that allows the commercial use of two-place, amateur-built gyroplanes for instructionalpurposes. One of the conditions of this exemption is tohave an approved flight manual for the aircraft. Thismanual is to be used for training purposes, and must becarried in the gyroplane at all times.

USING THE FLIGHT MANUALThe flight manual is required to be on board the aircraftto guarantee that the information contained therein isreadily available. For the information to be of value,you must be thoroughly familiar with the manual andbe able to read and properly interpret the various chartsand tables.

WEIGHT AND BALANCE SECTIONThe weight and balance section of the flight manualcontains information essential to the safe operation ofthe gyroplane. Careful consideration must be given tothe weight of the passengers, baggage, and fuel prior toeach flight. In conducting weight and balance compu-tations, many of the terms and procedures are similar tothose used in helicopters. These are further explainedin Chapter 7—Weight and Balance. In any aircraft,failure to adhere to the weight and balance limita-tions prescribed by the manufacturer can beextremely hazardous.

SAMPLE PROBLEMAs an example of a weight and balance computation,assume a sightseeing flight in a two-seat, tandem-con-figured gyroplane with two people aboard. The pilot,seated in the front, weighs 175 pounds while the rearseat passenger weighs 160 pounds. For the purposes ofthis example, there will be no baggage carried. Thebasic empty weight of the aircraft is 1,315 pounds witha moment, divided by 1,000, of 153.9 pound-inches.

ROTORCRAFT FLIGHT MANUAL

GENERAL—Presents basic information, such as loading, handling, and preflight of the gyroplane. Also includes definitions, abbreviations, symbology, and terminology explanations. LIMITATIONS—Includes operating limitations, instrument markings, color coding, and basic placards necessary for the safe operation of the gyroplane. EMERGENCY PROCEDURES—Provides checklists followed by amplified procedures for coping with various types of emergencies or critical situations. Related recommended airspeeds are also included. At the manufacturer's option, a section of abnormal procedures may be included to describe recommendations for handling equipment malfunctions or other abnormalities that are not of an emergency nature. NORMAL PROCEDURES—Includes checklists followed by amplified procedures for conducting normal operations. Related recommended airspeeds are also provided. PERFORMANCE—Gives performance information appropriate to the gyroplane, plus optional information presented in the most likely order for use in flight. WEIGHT AND BALANCE—Includes weighing procedures, weight and balance records, computation instructions, and the equipment list. AIRCRAFT AND SYSTEMS DESCRIPTION—Describes the gyroplane and its systems in a format considered by the manufacturer to be most informative. HANDLING, SERVICE, AND MAINTENANCE—Includes information on gyroplane inspection periods, preventative maintenance that can be performed by the pilot, ground handling procedures, servicing, cleaning, and care instructions. SUPPLEMENTS—Contains information necessary to safely and efficiently operate the gyroplane's various optional systems and equipment. SAFETY AND OPERATIONAL TIPS—Includes optional information from the manufacturer of a general nature addressing safety practices and procedures.

Figure 19-1. The FAA-approved flight manual may contain asmany as ten sections, as well as an optional alphabeticalindex.

19-2

Using the loading graph [Figure 19-2], themoment/1000 of the pilot is found to be 9.1 pound-inches, and the passenger has a moment/1000 of 13.4pound-inches.

Adding these figures, the total weight of the aircraft forthis flight (without fuel) is determined to be 1,650pounds with a moment/1000 of 176.4 pound-inches.[Figure 19-3]

The maximum gross weight for the sample aircraft is1,800 pounds, which allows up to 150 pounds to be car-ried in fuel. For this flight, 18 gallons of fuel is deemedsufficient. Allowing six pounds per gallon of fuel, thefuel weight on the aircraft totals 108 pounds. Referringagain to the loading graph [Figure 19-2], 108 pounds offuel would have a moment/1000 of 11.9 pound-inches.This is added to the previous totals to obtain the totalaircraft weight of 1,758 pounds and a moment/1000 of188.3. Locating this point on the center of gravity enve-lope chart [Figure 19-4], shows that the loading iswithin the prescribed weight and balance limits.

PERFORMANCE SECTIONThe performance section of the flight manual containsdata derived from actual flight testing of the aircraft.Because the actual performance may differ, it is pru-dent to maintain a margin of safety when planningoperations using this data.

SAMPLE PROBLEMFor this example, a gyroplane at its maximum grossweight (1,800 lbs.) needs to perform a short field take-off due to obstructions in the takeoff path. Presentweather conditions are standard temperature at a pres-sure altitude of 2,000 feet, and the wind is calm.Referring to the appropriate performance chart [Figure19-5], the takeoff distance to clear a 50-foot obstacle isdetermined by entering the chart from the left at thepressure altitude of 2,000 feet. You then proceed hori-zontally to the right until intersecting the appropriatetemperature reference line, which in this case is thedashed standard temperature line. From this point,descend vertically to find the total takeoff distance toclear a 50-foot obstacle. For the conditions given, thisparticular gyroplane would require a distance of 940feet for ground roll and the distance needed to climb 50feet above the surface. Notice that the data presented inthis chart is predicated on certain conditions, such as arunning takeoff to 30 m.p.h., a 50 m.p.h. climb speed, a

Weight Moment (pounds) (lb.-in./1,000)

Basic Empty Weight

Pilot

Passenger

Baggage

Total Aircraft (Less Fuel)

1,315

175

160

0

1,650

153.9

9.1

13.4

0

176.4

Max Gross Weight = 1,800 lbs.

Figure 19-3. Loading of the sample aircraft, less fuel.

CENTER OF GRAVITY ENVELOPE

Gross Moment in Thousands of LBS-IN.

Gro

ssW

eigh

tin

Pou

nds

(x10

0)

160 180 190 200170

15

16

17

18

1. Total Aircraft Weight (Less Fuel) ...............................

3. Fuel...........................................

TOTALS

Weight (lbs.)

Moment (lb.-ins. /1,000)

176.41,650

11.9108

188.31,758

AftForw

ard

Figure 19-4. Center of gravity envelope chart.

0 2 4 6 8 10 12 14 16 18 20

1

2

3

Load

Wei

ghti

nP

ound

s(x

100)

Load Moment in Thousands of LBS - IN

LOADING GRAPH

A

B

C

D

A = PilotB = Passenger

C = FuelD = Baggage

Figure 19-2. A loading graph is used to determine the loadmoment for weights at various stations.

19-3

rotor prerotation speed of 370 r.p.m., and no wind.Variations from these conditions alter performance,possibly to the point of jeopardizing the successful out-come of the maneuver.

HEIGHT/VELOCITY DIAGRAMLike helicopters, gyroplanes have a height/velocity diagram that defines what speed and altitude combina-tions allow for a safe landing in the event of an enginefailure. [Figure 19-6]

During an engine-out landing, the cyclic flare is used toarrest the vertical velocity of the aircraft and most of theforward velocity. On gyroplanes with a manual collec-tive control, increasing blade pitch just prior to touch-down can further reduce ground roll. Typically, agyroplane has a lower rotor disc loading than a helicop-ter, which provides a slower rate of descent in autorota-tion. The power required to turn the main transmission,tail rotor transmission, and tail rotor also add to thehigher descent rate of a helicopter in autorotation ascompared with that of a gyroplane.

EMERGENCY SECTIONBecause in-flight emergencies may not allow enoughtime to reference the flight manual, the emergency sec-tion should be reviewed periodically to maintainfamiliarity with these procedures. Many aircraft alsouse placards and instrument markings in the cockpit,

which provide important information that may not becommitted to memory.

Running Takeoff to 30 MPH & Climb out at 50 MPH CAS Weight 1800 LBS Rotor Prerotated to 370 RPM

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36

Total Takeoff Distance to Clear 50 FT Obstacle in Feet (x 100)

Pre

ssur

eA

ltitu

dein

Fee

t(x

1000

)

1

2

3

4

5

6

7

8

TOTAL TAKEOFF DISTANCE TO CLEAR 50 FT. OBSTACLE

Zero Wind

0° F20° F

Std. Temp.40° F60° F80° F

100° F

Figure 19-5. Takeoff performance chart.

HEIGHT vs. VELOCITY FOR SAFE LANDING

Avoid Continuous Operation In Shaded Area.

0 20 40 60 80 100

Indicated Airspeed In MPH

Hei

ghtA

bove

Run

way

InF

eet

400

300

200

100

0

Figure 19-6. Operations within the shaded area of aheight/velocity diagram may not allow for a safe landing andare to be avoided.

19-4

HANG TESTThe proper weight and balance of a gyroplane withouta flight manual is normally determined by conductinga hang test of the aircraft. This is achieved by remov-ing the rotor blades and suspending the aircraft by itsteeter bolt, free from contact with the ground. A meas-urement is then taken, either at the keel or the rotormast, to determine how many degrees from level the

gyroplane hangs. This number must be within therange specified by the manufacturer. For the test toreflect the true balance of the aircraft, it is importantthat it be conducted using the actual weight of the pilotand all gear normally carried in flight. Additionally,the measurement should be taken both with the fueltank full and with it empty to ensure that fuel burndoes not affect the loading.

20-1

The diversity of gyroplane designs available todayyields a wide variety of capability and performance.For safe operation, you must be thoroughly familiarwith the procedures and limitations for your particularaircraft along with other factors that may affect thesafety of your flight.

PREFLIGHTAs pilot in command, you are the final authority indetermining the airworthiness of your aircraft.Adherence to a preflight checklist greatly enhancesyour ability to evaluate the fitness of your gyroplane byensuring that a complete and methodical inspection ofall components is performed. [Figure 20-1] For aircraftwithout a formal checklist, it is prudent to create onethat is specific to the aircraft to be sure that importantitems are not overlooked. To determine the status ofrequired inspections, a preflight review of the aircraftrecords is also necessary.

COCKPIT MANAGEMENTAs in larger aircraft, cockpit management is an impor-tant skill necessary for the safe operation of a gyroplane. Intrinsic to these typically small aircraft is alimited amount of space that must be utilized to its

potential. The placement and accessibility of charts,writing materials, and other necessary items must becarefully considered. Gyroplanes with open cockpitsadd the challenge of coping with wind, which furtherincreases the need for creative and resourceful cockpitmanagement for optimum efficiency.

ENGINE STARTINGThe dissimilarity between the various types of enginesused for gyroplane propulsion necessitates the use ofan engine start checklist. Again, when a checklist is notprovided, it is advisable to create one for the safety ofyourself and others, and to prevent inadvertent damageto the engine or propeller. Being inherently dangerous,the propeller demands special attention during enginestarting procedures. Always ensure that the propellerarea is clear prior to starting. In addition to providingan added degree of safety, being thoroughly familiarwith engine starting procedures and characteristics canalso be very helpful in starting an engine under variousweather conditions.

TAXIINGThe ability of the gyroplane to be taxied greatlyenhances its utility. However, a gyroplane should notbe taxied in close proximity to people or obstructionswhile the rotor is turning. In addition, taxi speed shouldbe limited to no faster than a brisk walk in ideal condi-tions, and adjusted appropriately according to the circumstances.

BLADE FLAPOn a gyroplane with a semi-rigid, teeter-head rotor sys-tem, blade flap may develop if too much airflow passesthrough the rotor system while it is operating at lowr.p.m. This is most often the result of taxiing too fastfor a given rotor speed. Unequal lift acting on theadvancing and retreating blades can cause the blades toteeter to the maximum allowed by the rotor headdesign. The blades then hit the teeter stops, creating avibration that may be felt in the cyclic control. The fre-quency of the vibration corresponds to the speed of therotor, with the blades hitting the stops twice duringeach revolution. If the flapping is not controlled, thesituation can grow worse as the blades begin to flex and

Figure 20-1. A checklist is extremely useful in conducting athorough preflight inspection.

20-2

bend. Because the system is operating at low r.p.m.,there is not enough centrifugal force acting on theblades to keep them rigid. The shock of hitting theteeter stops combined with uneven lift along the lengthof the blade causes an undulation to begin, which canincrease in severity if allowed to progress. In extremecases, a rotor blade may strike the ground or propeller.[Figure 20-2]

To avoid the onset of blade flap, always taxi the gyro-plane at slow speeds when the rotor system is at lowr.p.m. Consideration must also be given to wind speedand direction. If taxiing into a 10-knot headwind, forexample, the airflow through the rotor will be 10 knotsfaster than the forward speed of the gyroplane, so thetaxi speed should be adjusted accordingly. When pre-rotating the rotor by taxiing with the rotor disc tiltedaft, allow the rotor to accelerate slowly and smoothly.In the event blade flap is encountered, apply forwardcyclic to reduce the rotor disc angle and slow the gyro-plane by reducing throttle and applying the brakes, ifneeded. [Figure 20-3]

BEFORE TAKEOFFFor the amateur-built gyroplane using single ignitionand a fixed trim system, the before takeoff check isquite simple. The engine should be at normal operatingtemperature, and the area must be clear for prerotation.Certificated gyroplanes using conventional aircraftengines have a checklist that includes items specific tothe powerplant. These normally include, but are notlimited to, checks for magneto drop, carburetor heat,and, if a constant speed propeller is installed, that it becycled for proper operation.

Following the engine run-up is the procedure foraccomplishing prerotation. This should be reviewedand committed to memory, as it typically requires bothhands to perform.

PREROTATIONPrerotation of the rotor can take many forms in a gyroplane. The most basic method is to turn the rotorblades by hand. On a typical gyroplane with a counter-clockwise rotating rotor, prerotation by hand is done onthe right side of the rotor disk. This allows body movement to be directed away from the propeller tominimize the risk of injury. Other methods of prerota-tion include using mechanical, electrical, or hydraulicmeans for the initial blade spin-up. Many of these systems can achieve only a portion of the rotor speedthat is necessary for takeoff. After the prerotator is disengaged, taxi the gyroplane with the rotor disk tiltedaft to allow airflow through the rotor. This increasesrotor speed to flight r.p.m. In windy conditions, facingthe gyroplane into the wind during prerotation assistsin achieving the highest possible rotor speed from theprerotator. A factor often overlooked that can nega-tively affect the prerotation speed is the cleanliness ofthe rotor blades. For maximum efficiency, it is recom-mended that the rotor blades be cleaned periodically.By obtaining the maximum possible rotor speedthrough the use of proper prerotation techniques, you

Figure 20-2. Taxiing too fast or gusting winds can causeblade flap in a slow turning rotor. If not controlled, a rotorblade may strike the ground.

Rotor Ground Clearance

Airflow

Rotor Ground Clearance

Airflow

Figure 20-3. Decreasing the rotor disc angle of attack with forward cyclic can reduce the excessive amount of airflow causingthe blade flap. This also allows greater clearance between the rotor blades and the surface behind the gyroplane, minimizingthe chances of a blade striking the ground.

20-3

minimize the length of the ground roll that is requiredto get the gyroplane airborne.

The prerotators on certificated gyroplanes remove thepossibility of blade flap during prerotation. Before theclutch can be engaged, the pitch must be removed fromthe blades. The rotor is then prerotated with a 0° angleof attack on the blades, which prevents lift from beingproduced and precludes the possibility of flapping.When the desired rotor speed is achieved, blade pitch isincreased for takeoff.

TAKEOFFTakeoffs are classified according to the takeoff surface,obstructions, and atmospheric conditions. Each type oftakeoff assumes that certain conditions exist. Whenconditions dictate, a combination of takeoff techniquescan be used. Two important speeds used for takeoff andinitial climbout are VX and VY. VX is defined as thespeed that provides the best angle of climb, and willyield the maximum altitude gain over a given distance.This speed is normally used when obstacles on theground are a factor. Maintaining VY speed ensures theaircraft will climb at its maximum rate, providing themost altitude gain for a given period of time. [Figure 20-4] Prior to any takeoff or maneuver, youshould ensure that the area is clear of other traffic.

NORMAL TAKEOFFThe normal takeoff assumes that a prepared surface ofadequate length is available and that there are no highobstructions to be cleared within the takeoff path. Thenormal takeoff for most amateur-built gyroplanes isaccomplished by prerotating to sufficient rotor r.p.m. toprevent blade flapping and tilting the rotor back withcyclic control. Using a speed of 20 to 30 m.p.h., allowthe rotor to accelerate and begin producing lift. As liftincreases, move the cyclic forward to decrease the pitchangle on the rotor disc. When appreciable lift is beingproduced, the nose of the aircraft rises, and you can feelan increase in drag. Using coordinated throttle andflight control inputs, balance the gyroplane on the maingear without the nose wheel or tail wheel in contactwith the surface. At this point, smoothly increase powerto full thrust and hold the nose at takeoff attitude withcyclic pressure. The gyroplane will lift off at or nearthe minimum power required speed for the aircraft. VXshould be used for the initial climb, then VY for theremainder of the climb phase.

A normal takeoff for certificated gyroplanes is accom-plished by prerotating to a rotor r.p.m. slightly abovethat required for flight and disengaging the rotor drive.The brakes are then released and full power is applied.Lift off will not occur until the blade pitch is increasedto the normal in-flight setting and the rotor disk tilted

Best Rate of Climb (V Y

)

BestAngle

of Climb (V X

)

30

Figure 20-4. Best angle-of-climb (VX) speed is used when obstacles are a factor. VY provides the most altitude gain for a givenamount of time.

20-4

power applied as soon as appreciable lift is felt. VXclimb speed should be maintained until the obstructionis cleared. Familiarity with the rotor acceleration characteristics and proper technique are essential foroptimum short-field performance.

If the prerotator is capable of spinning the rotor inexcess of normal flight r.p.m., the stored energy may beused to enhance short-field performance. Once maxi-mum rotor r.p.m. is attained, disengage the rotor drive,release the brakes, and apply power. As airspeed androtor r.p.m. increase, apply additional power until fullpower is achieved. While remaining on the ground,accelerate the gyroplane to a speed just prior to VX. Atthat point, tilt the disk aft and increase the blade pitchto the normal in-flight setting. The climb should be at aspeed just under VX until rotor r.p.m. has dropped tonormal flight r.p.m. or the obstruction has been cleared.When the obstruction is no longer a factor, increase theairspeed to VY.

COMMON ERRORS

1. Failure to position gyroplane for maximum utilization of available takeoff area.

2. Failure to check rotor for proper operation, track,and r.p.m. prior to takeoff.

3. Improper initial positioning of flight controls.

4. Improper application of power.

5. Improper use of brakes.

6. Poor directional control.

7. Failure to lift off at proper airspeed.

8. Failure to establish and maintain proper climbattitude and airspeed.

9. Drifting from the desired ground track during theclimb.

HIGH-ALTITUDE TAKEOFFA high-altitude takeoff is conducted in a manner verysimilar to that of the short-field takeoff, which achievesmaximum performance from the aircraft during eachphase of the maneuver. One important consideration isthat at higher altitudes, rotor r.p.m. is higher for a givenblade pitch angle. This higher speed is a result of thin-ner air, and is necessary to produce the same amount oflift. The inertia of the excess rotor speed should not beused in an attempt to enhance climb performance.Another important consideration is the effect of alti-tude on engine performance. As altitude increases, theamount of oxygen available for combustion decreases.In normally aspirated engines, it may be necessary to

aft. This is normally accomplished at approximately 30to 40 m.p.h. The gyroplane should then be allowed toaccelerate to VX for the initial climb, followed by VYfor the remainder of the climb. On any takeoff in agyroplane, engine torque causes the aircraft to rollopposite the direction of propeller rotation, and adequate compensation must be made.

CROSSWIND TAKEOFFA crosswind takeoff is much like a normal takeoff,except that you have to use the flight controls to compensate for the crosswind component. The termcrosswind component refers to that part of the windwhich acts at right angles to the takeoff path. Beforeattempting any crosswind takeoff, refer to the flightmanual, if available, or the manufacturer’s recommen-dations for any limitations.

Begin the maneuver by aligning the gyroplane into thewind as much as possible. At airports with wide runways, you might be able to angle your takeoff rolldown the runway to take advantage of as much head-wind as you can. As airspeed increases, gradually tiltthe rotor into the wind and use rudder pressure to maintain runway heading. In most cases, you shouldaccelerate to a speed slightly faster than normal liftoffspeed. As you reach takeoff speed, the downwind wheellifts off the ground first, followed by the upwind wheel.Once airborne, remove the cross-control inputs andestablish a crab, if runway heading is to be maintained.Due to the maneuverability of the gyroplane, an immedi-ate turn into the wind after lift off can be safely executed,if this does not cause a conflict with existing traffic.

COMMON ERRORS FOR NORMAL ANDCROSSWIND TAKEOFFS1. Failure to check rotor for proper operation, track,

and r.p.m. prior to takeoff.




5. Failure to lift off at proper airspeed.



SHORT-FIELD TAKEOFFShort-field takeoff and climb procedures may berequired when the usable takeoff surface is short, orwhen it is restricted by obstructions, such as trees, powerlines, or buildings, at the departure end. Thetechnique is identical to the normal takeoff, with performance being optimized during each phase. Usingthe help from wind and propwash, the maximum rotorr.p.m. should be attained from the prerotator and full

Normally Aspirated—An engine that does not compensate for decreasesin atmospheric pressure through turbocharging or other means.

20-5

adjust the fuel/air mixture to achieve the best possiblepower output. This process is referred to as “leaningthe mixture.” If you are considering a high-altitudetakeoff, and it appears that the climb performance limitof the gyroplane is being approached, do not attempt atakeoff until more favorable conditions exist.

SOFT-FIELD TAKEOFFA soft field may be defined as any takeoff surface thatmeasurably retards acceleration during the takeoff roll.The objective of the soft-field takeoff is to transfer theweight of the aircraft from the landing gear to the rotoras quickly and smoothly as possible to eliminate thedrag caused by surfaces, such as tall grass, soft dirt, orsnow. This takeoff requires liftoff at a speed just abovethe minimum level flight speed for the aircraft. Due todesign, many of the smaller gyroplanes have a limitedpitch attitude available, as tail contact with the groundprevents high pitch attitudes until in flight. At mini-mum level flight speed, the pitch attitude is often suchthat the tail wheel is lower than the main wheels. Whenperforming a soft-field takeoff, these aircraft requireslightly higher liftoff airspeeds to allow for proper tailclearance.

COMMON ERRORS

1. Failure to check rotor for proper operation, track,and r.p.m. prior to takeoff.



4. Allowing gyroplane to lose momentum by slowing or stopping on takeoff surface prior toinitiating takeoff.


6. Improper pitch attitude during lift-off.

7. Settling back to takeoff surface after becomingairborne.



JUMP TAKEOFFGyroplanes with collective pitch change, and the ability to prerotate the rotor system to speeds approxi-mately 50 percent higher than those required for normal flight, are capable of achieving extremely shorttakeoff rolls. Actual jump takeoffs can be performedunder the proper conditions. A jump takeoff requires noground roll, making it the most effective soft-field andcrosswind takeoff procedure. [Figure 20-5] A jumptakeoff is possible because the energy stored in theblades, as a result of the higher rotor r.p.m., is used tokeep the gyroplane airborne as it accelerates through

minimum level flight speed. Failure to have sufficientrotor r.p.m. for a jump takeoff results in the gyroplane settling back to the ground. Before attempting a jumptakeoff, it is essential that you first determine if it ispossible given the existing conditions by consulting therelevant performance chart. Should conditions ofweight, altitude, temperature, or wind leave the suc-cessful outcome of the maneuver in doubt, it should notbe attempted.

The prudent pilot may also use a “rule of thumb” forpredicting performance before attempting a jump take-off. As an example, suppose that a particular gyroplaneis known to be able to make a jump takeoff and remainairborne to accelerate to VX at a weight of 1,800 poundsand a density altitude of 2,000 feet. Since few takeoffsare made under these exact conditions, compensationmust be made for variations in weight, wind, and den-sity altitude. The “rule of thumb” being used for thisparticular aircraft stipulates that 1,000 feet of densityaltitude equates with 10 m.p.h. wind or 100 pounds ofgross weight. To use this equation, you must first deter-mine the density altitude. This is accomplished by setting your altimeter to the standard sea level pressuresetting of 29.92 inches of mercury and reading the pres-sure altitude. Next, you must correct for nonstandardtemperature. Standard temperature at sea level is 59°F(15°C) and decreases 3.5°F (2°C) for every additional

Figure 20-5. During a jump takeoff, excess rotor inertia isused to lift the gyroplane nearly vertical, where it is thenaccelerated through minimum level flight speed.

Density Altitude—Pressure altitude corrected for nonstandard temper-ature. This is a theoretical value that is used in determining aircraftperformance.

20-6

one thousand feet of pressure altitude. [Figure 20-6]Once you have determined the standard temperaturefor your pressure altitude, compare it with the actualexisting conditions. For every 10°F (5.5°C) the actualtemperature is above standard, add 750 feet to the pressure altitude to estimate the density altitude. If thedensity altitude is above 2,000 feet, a jump takeoff inthis aircraft should not be attempted unless wind and/ora weight reduction would compensate for the decreasein performance. Using the equation, if the density alti-tude is 3,000 feet (1,000 feet above a satisfactory jump density altitude), a reduction of 100 pounds in grossweight or a 10 m.p.h. of wind would still allow a satis-factory jump takeoff. Additionally, a reduction of 50pounds in weight combined with a 5 m.p.h. wind wouldalso allow a satisfactory jump. If it is determined that ajump takeoff should not be conducted because theweight cannot be reduced or an appropriate wind is notblowing, then consideration should be given to arolling takeoff. A takeoff roll of 10 m.p.h. is equivalentto a wind speed of 10 m.p.h. or a reduction of 100pounds in gross weight. It is important to note that ajump takeoff is predicated on having achieved a spe-cific rotor r.p.m. If this r.p.m. has not been attained,performance is unpredictable, and the maneuver shouldnot be attempted.

BASIC FLIGHT MANEUVERSConducting flight maneuvers in a gyroplane is differ-ent than in most other aircraft. Because of the wide

variety in designs, many gyroplanes have only basicinstruments available, and the pilot is often exposed tothe airflow. In addition, the visual clues found on otheraircraft, such as cowlings, wings, and windshieldsmight not be part of your gyroplane’s design.Therefore, much more reliance is placed on pilot interpretation of flight attitude and the “feel” of thegyroplane than in other types of aircraft. Acquiring theskills to precisely control a gyroplane can be a challenging and rewarding experience, but requiresdedication and the direction of a competent instructor.

STRAIGHT-AND-LEVEL FLIGHTStraight-and-level flight is conducted by maintaining aconstant altitude and a constant heading. In flight, agyroplane essentially acts as a plumb suspended fromthe rotor. As such, torque forces from the engine causethe airframe to be deflected a few degrees out of thevertical plane. This very slight “out of vertical” condition should be ignored and the aircraft flown tomaintain a constant heading.

The throttle is used to control airspeed. In level flight,when the airspeed of a gyroplane increases, the rotordisc angle of attack must be decreased. This causespitch control to become increasingly more sensitive.[Figure 20-7] As this disc angle becomes very small, itis possible to overcontrol a gyroplane when encounter-ing turbulence. For this reason, when extreme turbulence is encountered or expected, airspeed shouldbe decreased. Even in normal conditions, a gyroplanerequires constant attention to maintain straight-and-level flight. Although more stable than helicopters,gyroplanes are less stable than airplanes. When cyclictrim is available, it should be used to relieve any stickforces required during stabilized flight.

CLIMBS A climb is achieved by adding power in excess of whatis required for straight-and-level flight at a particularairspeed. The amount of excess power used is directlyproportional to the climb rate. For maneuvers when

Rotor Disk Angle

Low Speed

High Speed

F

Figure 20-7. The angle of the rotor disc decreases at highercruise speeds, which increases pitch control sensitivity.

20,00019,00018,00017,00016,00015,00014,00013,00012,00011,00010,0009,0008,0007,0006,0005,0004.0003,0002,0001,000

Sea Level

–25 –20 –15 –10 –5 0 5 10 15

–12 0 10 20 30 40 5950

°C

°F

Figure 20-6. Standard temperature chart.

20-7

maximum performance is desired, two important climbspeeds are best angle-of-climb speed and best rate-of-climb speed.

Because a gyroplane cannot be stalled, it may be tempt-ing to increase the climb rate by decreasing airspeed.This practice, however, is self-defeating. Operatingbelow the best angle-of-climb speed causes a diminish-ing rate of climb. In fact, if a gyroplane is slowed to theminimum level flight speed, it requires full power justto maintain altitude. Operating in this performancerealm, sometimes referred to as the “backside of thepower curve,” is desirable in some maneuvers, but canbe hazardous when maximum climb performance isrequired. For further explanation of a gyroplane powercurve, see Flight at Slow Airspeeds, which is discussedlater in this chapter.

DESCENTS A descent is the result of using less power than thatrequired for straight-and-level flight at a particular airspeed. Varying engine power during a descent allowsyou to choose a variety of descent profiles. In a power-offdescent, the minimum descent rate is achieved by usingthe airspeed that would normally be used for level flightat minimum power, which is also very close to the speedused for the best angle of climb. When distance is a factorduring a power-off descent, maximum gliding distancecan be achieved by maintaining a speed very close to thebest rate-of-climb airspeed. Because a gyroplane can besafely flown down to zero airspeed, a common error inthis type of descent is attempting to extend the glide byraising the pitch attitude. The result is a higher rate ofdescent and less distance being covered. For this reason,proper glide speed should be adhered to closely. Should astrong headwind exist, while attempting to achieve themaximum distance during a glide, a rule of thumb toachieve the greatest distance is to increase the glide speedby approximately 25 percent of the headwind. The atti-tude of the gyroplane for best glide performance islearned with experience, and slight pitch adjustments aremade for the proper airspeed. If a descent is needed tolose excess altitude, slowing the gyroplane to below thebest glide speed increases the rate of descent. Typically,slowing to zero airspeed results in a descent rate twicethat of maintaining the best glide speed.

TURNSTurns are made in a gyroplane by banking the rotor discwith cyclic control. Once the area, in the direction of theturn, has been cleared for traffic, apply sideward pres-sure on the cyclic until the desired bank angle isachieved. The speed at which the gyroplane enters thebank is dependent on how far the cyclic is displaced.When the desired bank angle is reached, return thecyclic to the neutral position. The rudder pedals are usedto keep the gyroplane in longitudinal trim throughoutthe turn, but not to assist in establishing the turn.

The bank angle used for a turn directly affects the rateof turn. As the bank is steepened, the turn rateincreases, but more power is required to maintain alti-tude. A bank angle can be reached where all availablepower is required, with any further increase in bankresulting in a loss of airspeed or altitude. Turns during aclimb should be made at the minimum angle of banknecessary, as higher bank angles would require morepower that would otherwise be available for the climb.Turns while gliding increase the rate of descent and maybe used as an effective way of losing excess altitude.

SLIPSA slip occurs when the gyroplane slides sidewaystoward the center of the turn. [Figure 20-8] It is causedby an insufficient amount of rudder pedal in the direc-tion of the turn, or too much in the direction oppositethe turn. In other words, holding improper rudder pedalpressure keeps the nose from following the turn, thegyroplane slips sideways toward the center of the turn.

SKIDSA skid occurs when the gyroplane slides sideways awayfrom the center of the turn. [Figure 20-9] It is caused bytoo much rudder pedal pressure in the direction of theturn, or by too little in the direction opposite the turn. Ifthe gyroplane is forced to turn faster with increasedpedal pressure instead of by increasing the degree of

Slip

InertiaHCL

Figure 20-8. During a slip, the rate of turn is too slow for theangle of bank used, and the horizontal component of lift(HCL) exceeds inertia. You can reestablish equilibrium bydecreasing the angle of bank, increasing the rate of turn byapplying rudder pedal, or a combination of the two.

Skid

HCL Inertia

Figure 20-9. During a skid, inertia exceeds the HCL. Toreestablish equilibrium, increase the bank angle or reducethe rate of turn by applying rudder pedal. You may also use acombination of these two corrections.

20-8

bank, it skids sideways away from the center of the turninstead of flying in its normal curved pattern.

COMMON ERRORS DURING BASIC FLIGHTMANEUVERS

1. Improper coordination of flight controls.

2. Failure to cross-check and correctly interpret outside and instrument references.

3. Using faulty trim technique.

STEEP TURNSA steep turn is a performance maneuver used in training that consists of a turn in either direction at abank angle of approximately 40°. The objective of performing steep turns is to develop smoothness, coor-dination, orientation, division of attention, and controltechniques.

Prior to initiating a steep turn, or any other flightmaneuver, first complete a clearing turn to check thearea for traffic. To accomplish this, you may executeeither one 180° turn or two 90° turns in opposite directions. Once the area has been cleared, roll thegyroplane into a 40° angle-of-bank turn whilesmoothly adding power and slowly moving the cyclicaft to maintain altitude. Maintain coordinated flightwith proper rudder pedal pressure. Throughout the turn,cross-reference visual cues outside the gyroplane withthe flight instruments, if available, to maintain a con-stant altitude and angle of bank. Anticipate the roll-outby leading the roll-out heading by approximately 20°.Using section lines or prominent landmarks to aid inorientation can be helpful in rolling out on the properheading. During roll-out, gradually return the cyclic tothe original position and reduce power to maintain altitude and airspeed.

COMMON ERRORS

1. Improper bank and power coordination duringentry and rollout.

2. Uncoordinated use of flight controls.

3. Exceeding manufacturer’s recommended maxi-mum bank angle.

4. Improper technique in correcting altitude deviations.

5. Loss of orientation.

6. Excessive deviation from desired heading duringrollout.

GROUND REFERENCE MANEUVERSGround reference maneuvers are training exercisesflown to help you develop a division of attentionbetween the flight path and ground references, whilecontrolling the gyroplane and watching for other

aircraft in the vicinity. Prior to each maneuver, a clear-ing turn should be accomplished to ensure the practicearea is free of conflicting traffic.

RECTANGULAR COURSEThe rectangular course is a training maneuver in whichthe ground track of the gyroplane is equidistant fromall sides of a selected rectangular area on the ground.[Figure 20-10] While performing the maneuver, thealtitude and airspeed should be held constant. The rec-tangular course helps you to develop a recognition of adrift toward or away from a line parallel to the intendedground track. This is helpful in recognizing drift towardor from an airport runway during the various legs of theairport traffic pattern.

For this maneuver, pick a square or rectangular field, oran area bounded on four sides by section lines or roads,where the sides are approximately a mile in length. Thearea selected should be well away from other air traf-fic. Fly the maneuver approximately 600 to 1,000 feetabove the ground, which is the altitude usually requiredfor an airport traffic pattern. You should fly the gyroplane parallel to and at a uniform distance, aboutone-fourth to one-half mile, from the field boundaries,not above the boundaries. For best results, positionyour flight path outside the field boundaries just farenough away that they may be easily observed. Youshould be able to see the edges of the selected fieldwhile seated in a normal position and looking out theside of the gyroplane during either a left-hand or right-hand course. The distance of the ground track from theedges of the field should be the same regardless ofwhether the course is flown to the left or right. All turnsshould be started when your gyroplane is abeam thecorners of the field boundaries. The bank normallyshould not exceed 30°.

Although the rectangular course may be entered fromany direction, this discussion assumes entry on a down-wind heading. As you approach the field boundary onthe downwind leg, you should begin planning for yourturn to the crosswind leg. Since you have a tailwind onthe downwind leg, the gyroplane’s groundspeed isincreased (position 1). During the turn onto the cross-wind leg, which is the equivalent of the base leg in atraffic pattern, the wind causes the gyroplane to driftaway from the field. To counteract this effect, the roll-in should be made at a fairly fast rate with a relativelysteep bank (position 2).

As the turn progresses, the tailwind componentdecreases, which decreases the groundspeed.Consequently, the bank angle and rate of turn must bereduced gradually to ensure that upon completion ofthe turn, the crosswind ground track continues to be thesame distance from the edge of the field. Upon comple-tion of the turn, the gyroplane should be level and

20-9

aligned with the downwind corner of the field.However, since the crosswind is now pushing youaway from the field, you must establish the proper driftcorrection by flying slightly into the wind. Therefore,the turn to crosswind should be greater than a 90°change in heading (position 3). If the turn has beenmade properly, the field boundary again appears to beone-fourth to one-half mile away. While on the cross-wind leg, the wind correction should be adjusted, asnecessary, to maintain a uniform distance from the fieldboundary (position 4).

As the next field boundary is being approached (posi-tion 5), plan the turn onto the upwind leg. Since a windcorrection angle is being held into the wind and towardthe field while on the crosswind leg, this next turnrequires a turn of less than 90°. Since the crosswindbecomes a headwind, causing the groundspeed todecrease during this turn, the bank initially must bemedium and progressively decreased as the turn pro-ceeds. To complete the turn, time the rollout so that thegyroplane becomes level at a point aligned with thecorner of the field just as the longitudinal axis of thegyroplane again becomes parallel to the field boundary(position 6). The distance from the field boundaryshould be the same as on the other sides of the field.

On the upwind leg, the wind is a headwind, whichresults in an decreased groundspeed (position 7).Consequently, enter the turn onto the next leg with afairly slow rate of roll-in, and a relatively shallow bank(position 8). As the turn progresses, gradually increasethe bank angle because the headwind component isdiminishing, resulting in an increasing groundspeed.During and after the turn onto this leg, the wind tendsto drift the gyroplane toward the field boundary. Tocompensate for the drift, the amount of turn must beless than 90° (position 9).

Again, the rollout from this turn must be such that asthe gyroplane becomes level, the nose of the gyroplaneis turned slightly away the field and into the wind tocorrect for drift. The gyroplane should again be thesame distance from the field boundary and at the samealtitude, as on other legs. Continue the crosswind leguntil the downwind leg boundary is approached (posi-tion 10). Once more you should anticipate drift andturning radius. Since drift correction was held on thecrosswind leg, it is necessary to turn greater than 90° toalign the gyroplane parallel to the downwind legboundary. Start this turn with a medium bank angle,gradually increasing it to a steeper bank as the turn pro-gresses. Time the rollout to assure paralleling the

WIND

No Crab

Start Turn At Boundary

Complete Turn At Boundary

Turn less Than 90°—Roll Out With Crab Established

Crab Into Wind


Turn More Than 90°

Enter Pattern


No CrabStart Turn At Boundary

Turn More Than 90°—Roll Out With Crab Established


Crab Into Wind


Turn Less Than 90°


Trac

kW

ithN

oW

ind

Cor

rect

ion

Figure 20-10. Rectangular course. The numbered positions in the text refer to the numbers in this illustration.

20-10

boundary of the field as the gyroplane becomes level(position 11).

If you have a direct headwind or tailwind on the upwindand downwind leg, drift should not be encountered.However, it may be difficult to find a situation wherethe wind is blowing exactly parallel to the field bound-aries. This makes it necessary to use a slight wind correction angle on all the legs. It is important to antici-pate the turns to compensate for groundspeed, drift, andturning radius. When the wind is behind the gyroplane,the turn must be faster and steeper; when it is ahead ofthe gyroplane, the turn must be slower and shallower.These same techniques apply while flying in an airporttraffic pattern.

S-TURNSAnother training maneuver you might use is the S-turn,which helps you correct for wind drift in turns. Thismaneuver requires turns to the left and right. The refer-ence line used, whether a road, railroad, or fence,should be straight for a considerable distance andshould extend as nearly perpendicular to the wind aspossible.

The object of S-turns is to fly a pattern of two half circles of equal size on opposite sides of the referenceline. [Figure 20-11] The maneuver should be performed at a constant altitude of 600 to 1,000 feetabove the terrain. S-turns may be started at any point;however, during early training it may be beneficial tostart on a downwind heading. Entering downwind permits the immediate selection of the steepest bank

that is desired throughout the maneuver. The discus-sion that follows is based on choosing a reference linethat is perpendicular to the wind and starting themaneuver on a downwind heading.

As the gyroplane crosses the reference line, immedi-ately establish a bank. This initial bank is the steepest

used throughout the maneuver since the gyroplane isheaded directly downwind and the groundspeed is at itshighest. Gradually reduce the bank, as necessary, todescribe a ground track of a half circle. Time the turnso that as the rollout is completed, the gyroplane iscrossing the reference line perpendicular to it and head-ing directly upwind. Immediately enter a bank in theopposite direction to begin the second half of the “S.”Since the gyroplane is now on an upwind heading, thisbank (and the one just completed before crossing thereference line) is the shallowest in the maneuver.Gradually increase the bank, as necessary, to describe aground track that is a half circle identical in size to theone previously completed on the other side of the refer-ence line. The steepest bank in this turn should beattained just prior to rollout when the gyroplane isapproaching the reference line nearest the downwindheading. Time the turn so that as the rollout is com-plete, the gyroplane is perpendicular to the referenceline and is again heading directly downwind.

In summary, the angle of bank required at any givenpoint in the maneuver is dependent on the ground-speed. The faster the groundspeed, the steeper thebank; the slower the groundspeed, the shallower the bank. To express it another way, the more nearlythe gyroplane is to a downwind heading, the steeper thebank; the more nearly it is to an upwind heading, theshallower the bank. In addition to varying the angle ofbank to correct for drift in order to maintain the properradius of turn, the gyroplane must also be flown with adrift correction angle (crab) in relation to its groundtrack; except of course, when it is on direct upwind ordownwind headings or there is no wind. One wouldnormally think of the fore and aft axis of the gyroplaneas being tangent to the ground track pattern at eachpoint. However, this is not the case. During the turn onthe upwind side of the reference line (side from whichthe wind is blowing), crab the nose of the gyroplanetoward the outside of the circle. During the turn on thedownwind side of the reference line (side of the refer-ence line opposite to the direction from which the windis blowing), crab the nose of the gyroplane toward theinside of the circle. In either case, it is obvious that thegyroplane is being crabbed into the wind just as it iswhen trying to maintain a straight ground track. Theamount of crab depends upon the wind velocity andhow nearly the gyroplane is to a crosswind position.The stronger the wind, the greater the crab angle at anygiven position for a turn of a given radius. The morenearly the gyroplane is to a crosswind position, thegreater the crab angle. The maximum crab angle shouldbe at the point of each half circle farthest from the reference line.

A standard radius for S-turns cannot be specified, sincethe radius depends on the airspeed of the gyroplane, the

Points of Shallowest Bank

Points of Steepest Bank

WIND

Figure 20-11. S-turns across a road.

20-11

velocity of the wind, and the initial bank chosen forentry.

TURNS AROUND A POINTThis training maneuver requires you to fly constantradius turns around a preselected point on the groundusing a maximum bank of approximately 40°, whilemaintaining a constant altitude. [Figure 20-12] Yourobjective, as in other ground reference maneuvers, is todevelop the ability to subconsciously control the gyro-plane while dividing attention between the flight pathand ground references, while still watching for otherair traffic in the vicinity.

The factors and principles of drift correction that areinvolved in S-turns are also applicable in this maneu-ver. As in other ground track maneuvers, a constantradius around a point will, if any wind exists, require aconstantly changing angle of bank and angles of windcorrection. The closer the gyroplane is to a directdownwind heading where the groundspeed is greatest,the steeper the bank, and the faster the rate of turnrequired to establish the proper wind correction angle.The more nearly it is to a direct upwind heading wherethe groundspeed is least, the shallower the bank, andthe slower the rate of turn required to establish the proper wind correction angle. It follows then, that throughout the maneuver, the bank and rate of turn must be gradually varied in proportion to the groundspeed.

The point selected for turns around a point should beprominent and easily distinguishable, yet small enoughto present a precise reference. Isolated trees,

crossroads, or other similar small landmarks are usu-ally suitable. The point should be in an area away fromcommunities, livestock, or groups of people on theground to prevent possible annoyance or hazard to others. Since the maneuver is performed between 600and 1,000 feet AGL, the area selected should alsoafford an opportunity for a safe emergency landing inthe event it becomes necessary.

To enter turns around a point, fly the gyroplane on adownwind heading to one side of the selected point at adistance equal to the desired radius of turn. When anysignificant wind exists, it is necessary to roll into theinitial bank at a rapid rate so that the steepest bank isattained abeam the point when the gyroplane is headeddirectly downwind. By entering the maneuver whileheading directly downwind, the steepest bank can beattained immediately. Thus, if a bank of 40° is desired,the initial bank is 40° if the gyroplane is at the correctdistance from the point. Thereafter, the bank is gradu-ally shallowed until the point is reached where thegyroplane is headed directly upwind. At this point, thebank is gradually steepened until the steepest bank isagain attained when heading downwind at the initialpoint of entry.

Just as S-turns require that the gyroplane be turned intothe wind, in addition to varying the bank, so do turnsaround a point. During the downwind half of the circle,the gyroplane’s nose must be progressively turnedtoward the inside of the circle; during the upwind half,the nose must be progressively turned toward the out-side. The downwind half of the turn around the pointmay be compared to the downwind side of the S-turn,while the upwind half of the turn around a point may becompared to the upwind side of the S-turn.

As you become experienced in performing turnsaround a point and have a good understanding of theeffects of wind drift and varying of the bank angle andwind correction angle, as required, entry into themaneuver may be from any point. When entering thismaneuver at any point, the radius of the turn must becarefully selected, taking into account the wind veloc-ity and groundspeed, so that an excessive bank is notrequired later on to maintain the proper ground track.

COMMON ERRORS DURING GROUNDREFERENCE MANEUVERS

1. Faulty entry technique.

2. Poor planning, orientation, or division of attention.

3. Uncoordinated flight control application.

4. Improper correction for wind drift.

UPP

ER HALF OF CIRCLE

DO

W

NWIND HALF OF CIRC

LE

Shallowest

Bank

Steeper Bank

Steepest

Bank

Shallower Bank

WIND

F

Figure 20-12. Turns around a point.

20-12

5. An unsymmetrical ground track during S-turnsacross a road.

6. Failure to maintain selected altitude or airspeed.

7. Selection of a ground reference where there is nosuitable emergency landing site.

FLIGHT AT SLOW AIRSPEEDSThe purpose of maneuvering during slow flight is tohelp you develop a feel for controlling the gyroplane atslow airspeeds, as well as gain an understanding of howload factor, pitch attitude, airspeed, and altitude controlrelate to each other.

Like airplanes, gyroplanes have a specific amount ofpower that is required for flight at various airspeeds, anda fixed amount of power available from the engine. Thisdata can be charted in a graph format. [Figure 20-13]The lowest point of the power required curve representsthe speed at which the gyroplane will fly in level flightwhile using the least amount of power. To fly faster thanthis speed, or slower, requires more power. While practicing slow flight in a gyroplane, you will likely beoperating in the performance realm on the chart that isleft of the minimum power required speed. This is oftenreferred to as the “backside of the power curve,” or flying “behind the power curve.” At these speeds, aspitch is increased to slow the gyroplane, more and morepower is required to maintain level flight. At the pointwhere maximum power available is being used, no further reduction in airspeed is possible without initiat-ing a descent. This speed is referred to as the minimumlevel flight speed. Because there is no excess poweravailable for acceleration, recovery from minimum levelflight speed requires lowering the nose of the gyroplaneand using altitude to regain airspeed. For this reason, it isessential to practice slow flight at altitudes that allowsufficient height for a safe recovery. Unintentionally flying a gyroplane on the backside of the power curveduring approach and landing can be extremely

hazardous. Should a go-around become necessary, sufficient altitude to regain airspeed and initiate a climbmay not be available, and ground contact may beunavoidable.

Flight at slow airspeeds is usually conducted at air-speeds 5 to 10 m.p.h. above the minimum level flightairspeed. When flying at slow airspeeds, it is importantthat your control inputs be smooth and slow to preventa rapid loss of airspeed due to the high drag increaseswith small changes in pitch attitude. In addition, turnsshould be limited to shallow bank angles. In order toprevent losing altitude during turns, power must beadded. Directional control remains very good whileflying at slow airspeeds, because of the high velocityslipstream produced by the increased engine power.

Recovery to cruise flight speed is made by loweringthe nose and increasing power. When the desired speedis reached, reduce power to the normal cruise powersetting.

COMMON ERRORS

1. Improper entry technique.

2. Failure to establish and maintain an appropriateairspeed.

3. Excessive variations of altitude and headingwhen a constant altitude and heading are specified.

4. Use of too steep a bank angle.

5. Rough or uncoordinated control technique.

HIGH RATE OF DESCENTA gyroplane will descend at a high rate when flown atvery low forward airspeeds. This maneuver may beentered intentionally when a steep descent is desired,and can be performed with or without power. An unin-tentional high rate of descent can also occur as a result

0 20 40 85 Airspeed, MPH

Power Available for Climb and Acceleration

Power Required

Engine Power Available at Full Throttle

Rat

eo

fC

limb

Des

cen

t 20 45 85

Power Required & Power Available vs. Airspeed Rates of Climb & Descent at Full Throttle

0 Airspeed, MPH

TYPICAL GYROPLANE

Hor

sepo

wer

Minimum Level Flight Speed

Figure 20-13. The low point on the power required curve is the speed that the gyroplane can fly while using the least amount ofpower, and is also the speed that will result in a minimum sink rate in a power-off glide.

20-13

of failing to monitor and maintain proper airspeed. Inpowered flight, if the gyroplane is flown below mini-mum level flight speed, a descent results even thoughfull engine power is applied. Further reducing the air-speed with aft cyclic increases the rate of descent. Forgyroplanes with a high thrust-to-weight ratio, thismaneuver creates a very high pitch attitude. To recover,the nose of the gyroplane must lowered slightly toexchange altitude for an increase in airspeed.

When operating a gyroplane in an unpowered glide,slowing to below the best glide speed can also result ina high rate of descent. As airspeed decreases, the rate ofdescent increases, reaching the highest rate as forwardspeed approaches zero. At slow airspeeds without theengine running, there is very little airflow over the tailsurfaces and rudder effectiveness is greatly reduced.Rudder pedal inputs must be exaggerated to maintaineffective yaw control. To recover, add power, if avail-able, or lower the nose and allow the gyroplane toaccelerate to the proper airspeed. This maneuverdemonstrates the importance of maintaining the properglide speed during an engine-out emergency landing.Attempting to stretch the glide by raising the noseresults in a higher rate of descent at a lower forwardspeed, leaving less distance available for the selectionof a landing site.

COMMON ERRORS

1. Improper entry technique.

2. Failure to recognize a high rate of descent.

3. Improper use of controls during recovery.

4. Initiation of recovery below minimum recoveryaltitude.

LANDINGSLandings may be classified according to the landingsurface, obstructions, and atmospheric conditions.Each type of landing assumes that certain conditionsexist. To meet the actual conditions, a combination oftechniques may be necessary.

NORMAL LANDINGThe procedure for a normal landing in a gyroplane ispredicated on having a prepared landing surface and nosignificant obstructions in the immediate area. Afterentering a traffic pattern that conforms to establishedstandards for the airport and avoids the flow of fixedwing traffic, a before landing checklist should bereviewed. The extent of the items on the checklist isdependent on the complexity of the gyroplane, and caninclude fuel, mixture, carburetor heat, propeller, engineinstruments, and a check for traffic.

Gyroplanes experience a slight lag between controlinput and aircraft response. This lag becomes more

apparent during the sensitive maneuvering requiredfor landing, and care must be taken to avoid overcor-recting for deviations from the desired approach path.After the turn to final, the approach airspeed appropri-ate for the gyroplane should be established. This speedis normally just below the minimum power requiredspeed for the gyroplane in level flight. During theapproach, maintain this airspeed by making adjust-ments to the gyroplane’s pitch attitude, as necessary.Power is used to control the descent rate.

Approximately 10 to 20 feet above the runway, beginthe flare by gradually increasing back pressure on thecyclic to reduce speed and decrease the rate of descent.The gyroplane should reach a near-zero rate of descentapproximately 1 foot above the runway with the powerat idle. Low airspeed combined with a minimum ofpropwash over the tail surfaces reduces rudder effectiveness during the flare. If a yaw moment isencountered, use whatever rudder control is requiredto maintain the desired heading. The gyroplane shouldbe kept laterally level and with the longitudinal axis inthe direction of ground track. Landing with sidewardmotion can damage the landing gear and must beavoided. In a full-flare landing, attempt to hold thegyroplane just off the runway by steadily increasingback pressure on the cyclic. This causes the gyroplaneto settle slowly to the runway in a slightly nose-highattitude as forward momentum dissipates.

Ground roll for a full-flare landing is typically under50 feet, and touchdown speed under 20 m.p.h. If a 20m.p.h. or greater headwind exists, it may be necessaryto decrease the length of the flare and allow the gyro-plane to touch down at a slightly higher airspeed toprevent it from rolling backward on landing. Aftertouchdown, rotor r.p.m. decays rather rapidly. Onlandings where brakes are required immediately aftertouchdown, apply them lightly, as the rotor is still car-rying much of the weight of the aircraft and too muchbraking causes the tires to skid.

SHORT-FIELD LANDING A short-field landing is necessary when you have a rel-atively short landing area or when an approach must bemade over obstacles that limit the available landingarea. When practicing short-field landings, assume youare making the approach and landing over a 50-footobstruction in the approach area.

To conduct a short-field approach and landing, fol-low normal procedures until you are established onthe final approach segment. At this point, use aftcyclic to reduce airspeed below the speed for mini-mum sink. By decreasing speed, sink rate increasesand a steeper approach path is achieved, minimizingthe distance between clearing the obstacle and

20-14

making contact with the surface. [Figure 20-14] Theapproach speed must remain fast enough, however,to allow the flare to arrest the forward and verticalspeed of the gyroplane. If the approach speed is toolow, the remaining vertical momentum will result ina hard landing. On a short-field landing with a slightheadwind, a touchdown with no ground roll is possi-ble. Without wind, the ground roll is normally lessthan 50 feet.

SOFT-FIELD LANDINGUse the soft-field landing technique when the landingsurface presents high wheel drag, such as mud, snow,sand, tall grass or standing water. The objective is totransfer the weight of the gyroplane from the rotor tothe landing gear as gently and slowly as possible. Witha headwind close to the touchdown speed of the gyroplane, a power approach can be made close to theminimum level flight speed. As you increase the nosepitch attitude just prior to touchdown, add additionalpower to cushion the landing. However, power shouldbe removed, just as the wheels are ready to touch. Thisresults is a very slow, gentle touchdown. In a strongheadwind, avoid allowing the gyroplane to roll rear-ward at touchdown. After touchdown, smoothly andgently lower the nosewheel to the ground. Minimizethe use of brakes, and remain aware that the nosewheelcould dig in the soft surface.

When no wind exists, use a steep approach similar to ashort-field landing so that the forward speed can be dis-sipated during the flare. Use the throttle to cushion thetouchdown.

CROSSWIND LANDING Crosswind landing technique is normally used in gyro-planes when a crosswind of approximately 15 m.p.h. orless exists. In conditions with higher crosswinds, itbecomes very difficult, if not impossible, to maintainadequate compensation for the crosswind. In these con-ditions, the slow touchdown speed of a gyroplaneallows a much safer option of turning directly into thewind and landing with little or no ground roll. Decidingwhen to use this technique, however, may be complicated by gusting winds or the characteristics ofthe particular landing area.

On final approach, establish a crab angle into the windto maintain a ground track that is aligned with theextended centerline of the runway. Just before touchdown, remove the crab angle and bank the gyroplane slightly into the wind to prevent drift.Maintain longitudinal alignment with the runway usingthe rudder. In higher crosswinds, if full rudder deflec-tion is not sufficient to maintain alignment with the run-way, applying a slight amount of power can increaserudder effectiveness. The length of the flare should bereduced to allow a slightly higher touchdown speed thanthat used in a no-wind landing. Touchdown is made onthe upwind main wheel first, with the other main wheelsettling to the runway as forward momentum is lost.After landing, continue to keep the rotor tilted into thewind to maintain positive control during the rollout.

HIGH-ALTITUDE LANDING A high-altitude landing assumes a density altitude nearthe limit of what is considered good climb performance

50'

Normal Approach

Short Field Approach

Figure 20-14. The airspeed used on a short-field approach is slower than that for a normal approach, allowing a steeperapproach path and requiring less runway.

20-15

for the gyroplane. When using the same indicated airspeed as that used for a normal approach at loweraltitude, a high density altitude results in higher rotorr.p.m. and a slightly higher rate of descent. The greatervertical velocity is a result of higher true airspeed ascompared with that at low altitudes. When practicinghigh-altitude landings, it is prudent to first learn normallandings with a flare and roll out. Full flare, no rolllandings should not be attempted until a good feel foraircraft response at higher altitudes has been acquired.As with high-altitude takeoffs, it is also important toconsider the effects of higher altitude on engine performance.

COMMON ERRORS DURING LANDING

1. Failure to establish and maintain a stabilizedapproach.

2. Improper technique in the use of power.

3. Improper technique during flare or touchdown.

4. Touchdown at too low an airspeed with strongheadwinds, causing a rearward roll.

5. Poor directional control after touchdown.

6. Improper use of brakes.

GO-AROUNDThe go-around is used to abort a landing approachwhen unsafe factors for landing are recognized. If thedecision is made early in the approach to go around,normal climb procedures utilizing VX and VY shouldbe used. A late decision to go around, such as after thefull flare has been initiated, may result in an airspeedwhere power required is greater than power available.When this occurs, a touchdown becomes unavoidableand it may be safer to proceed with the landing than tosustain an extended ground roll that would be required

to go around. Also, the pitch attitude of the gyroplanein the flare is high enough that the tail would be con-siderably lower than the main gear, and a touch downwith power on would result in a sudden pitch down andacceleration of the aircraft. Control of the gyroplaneunder these circumstances may be difficult.Consequently, the decision to go around should bemade as early as possible, before the speed is reducedbelow the point that power required exceeds poweravailable.

COMMON ERRORS

1. Failure to recognize a situation where a go-around is necessary.


3. Failure to control pitch attitude.

4. Failure to maintain recommended airspeeds.

5. Failure to maintain proper track during climb out.

AFTER LANDING AND SECURING The after-landing checklist should include such itemsas the transponder, cowl flaps, fuel pumps, lights, andmagneto checks, when so equipped. The rotor bladesdemand special consideration after landing, as turningrotor blades can be hazardous to others. Never enter anarea where people or obstructions are present with therotor turning. To assist the rotor in slowing, tilt thecyclic control into the prevailing wind or face the gyro-plane downwind. When slowed to under approximately75 r.p.m., the rotor brake may be applied, if available.Use caution as the rotor slows, as excess taxi speed orhigh winds could cause blade flap to occur. The bladesshould be depitched when taxiing if a collective controlis available. When leaving the gyroplane, alwayssecure the blades with a tiedown or rotor brake.

21-1

Gyroplanes are quite reliable, however emergencies dooccur, whether a result of mechanical failure or piloterror. By having a thorough knowledge of the gyroplane and its systems, you will be able to morereadily handle the situation. In addition, by knowingthe conditions which can lead to an emergency, manypotential accidents can be avoided.

ABORTED TAKEOFFPrior to every takeoff, consideration must be given to acourse of action should the takeoff become undesirableor unsafe. Mechanical failures, obstructions on thetakeoff surface, and changing weather conditions areall factors that could compromise the safety of a take-off and constitute a reason to abort. The decision toabort a takeoff should be definitive and made as soonas an unsafe condition is recognized. By initiating theabort procedures early, more time and distance will beavailable to bring the gyroplane to a stop. A late deci-sion to abort, or waiting to see if it will be necessary toabort, can result in a dangerous situation with little timeto respond and very few options available.

When initiating the abort sequence prior to thegyroplane leaving the surface, the procedure is quitesimple. Reduce the throttle to idle and allow the gyroplane to decelerate, while slowly applying aftcyclic for aerodynamic braking. This technique pro-vides the most effective braking and slows the aircraftvery quickly. If the gyroplane has left the surface whenthe decision to abort is made, reduce the throttle untilan appropriate descent rate is achieved. Once contactwith the surface is made, reduce the throttle to idle andapply aerodynamic braking as before. The wheelbrakes, if the gyroplane is so equipped, may be applied,as necessary, to assist in slowing the aircraft.

ACCELERATE/STOP DISTANCEAn accelerate/stop distance is the length of ground rollan aircraft would require to accelerate to takeoff speedand, assuming a decision to abort the takeoff is made,bring the aircraft safely to a stop. This value changesfor a given aircraft based on atmospheric conditions,the takeoff surface, aircraft weight, and other factorsaffecting performance. Knowing the accelerate/stopvalue for your gyroplane can be helpful in planning a

safe takeoff, but having this distance available does notnecessarily guarantee a safe aborted takeoff is possiblefor every situation. If the decision to abort is made afterliftoff, for example, the gyroplane will require consid-erably more distance to stop than the accelerate/stopfigure, which only considers the ground roll require-ment. Planning a course of action for an abort decisionat various stages of the takeoff is the best way to ensurethe gyroplane can be brought safely to a stop should theneed arise.

For a gyroplane without a flight manual or other pub-lished performance data, the accelerate/stop distancecan be reasonably estimated once you are familiar withthe performance and takeoff characteristics of the air-craft. For a more accurate figure, you can accelerate thegyroplane to takeoff speed, then slow to a stop, andnote the distance used. Doing this several times givesyou an average accelerate/stop distance. When per-formance charts for the aircraft are available, as in theflight manual of a certificated gyroplane, accurateaccelerate/stop distances under various conditions canbe determined by referring to the ground roll informa-tion contained in the charts.

LIFT-OFF AT LOW AIRSPEED ANDHIGH ANGLE OF ATTACKBecause of ground effect, your gyroplane might be ableto become airborne at an airspeed less than minimumlevel flight speed. In this situation, the gyroplane is fly-ing well behind the power curve and at such a highangle of attack that unless a correction is made, therewill be little or no acceleration toward best climbspeed. This condition is often encountered in gyroplanes capable of jump takeoffs. Jumping without sufficient rotor inertia to allow enough time to acceler-ate through minimum level flight speed, usually resultsin your gyroplane touching down after liftoff. If you dotouch down after performing a jump takeoff, youshould abort the takeoff.

During a rolling takeoff, if the gyroplane is forced intothe air too early, you could get into the same situation.It is important to recognize this situation and takeimmediate corrective action. You can either abort thetakeoff, if enough runway exists, or lower the nose and

21-2

accelerate to the best climb speed. If you choose to con-tinue the takeoff, verify that full power is applied, then,slowly lower the nose, making sure the gyroplane doesnot contact the surface. While in ground effect, acceler-ate to the best climb speed. Then, adjust the nose pitchattitude to maintain that airspeed.

COMMON ERRORSThe following errors might occur when practicing alift-off at a low airspeed.

1. Failure to check rotor for proper operation, track,and r.p.m. prior to initiating takeoff.

2. Use of a power setting that does not simulate a“behind the power curve” situation.


4. Rotation at a speed that is inappropriate for themaneuver.

5. Poor judgement in determining whether to abortor continue takeoff.

6. Failure to establish and maintain proper climbattitude and airspeed, if takeoff is continued.

7. Not maintaining the desired ground track duringthe climb.

PILOT-INDUCED OSCILLATION (PIO)Pilot-induced oscillation, sometimes referred to as por-poising, is an unintentional up-and-down oscillation ofthe gyroplane accompanied with alternating climbs anddescents of the aircraft. PIO is often the result of aninexperienced pilot overcontrolling the gyroplane, butthis condition can also be induced by gusty wind con-ditions. While this condition is usually thought of as alongitudinal problem, it can also happen laterally.

As with most other rotor-wing aircraft, gyroplanesexperience a slight delay between control input and thereaction of the aircraft. This delay may cause an inex-perienced pilot to apply more control input thanrequired, causing a greater aircraft response than wasdesired. Once the error has been recognized, oppositecontrol input is applied to correct the flight attitude.Because of the nature of the delay in aircraft response,it is possible for the corrections to be out of synchro-nization with the movements of the aircraft and aggra-vate the undesired changes in attitude. The result isPIO, or unintentional oscillations that can grow rapidlyin magnitude. [Figure 21-1]

In gyroplanes with an open cockpit and limited flightinstruments, it can be difficult for an inexperiencedpilot to recognize a level flight attitude due to the lackof visual references. As a result, PIO can develop as thepilot chases a level flight attitude and introduces climb-ing and descending oscillations. PIO can also developif a wind gust displaces the aircraft, and the controlinputs made to correct the attitude are out of phase withthe aircraft movements. Because the rotor disc angledecreases at higher speeds and cyclic control becomesmore sensitive, PIO is more likely to occur and can bemore pronounced at high airspeeds. To minimize thepossibility of PIO, avoid high-speed flight in gustyconditions, and make only small control inputs. Aftermaking a control input, wait briefly and observe thereaction of the aircraft before making another input. IfPIO is encountered, reduce power and place the cyclicin the position for a normal climb. Once the oscillationshave stopped, slowly return the throttle and cyclic totheir normal positions. The likelihood of encounteringPIO decreases greatly as experience is gained, and theability to subconsciously anticipate the reactions of thegyroplane to control inputs is developed.

Normal Flight

Variance from desired flight path recognized,

control input made to correct

Gyroplane reacts

Gyroplane reacts

Gyroplane reacts

Overcorrection recognized, larger control input made

to correct

Overcorrection recognized, larger input control made

to correct

Figure 21-1. Pilot-induced oscillation can result if the gyroplane’s reactions to control inputs are not anticipated and becomeout of phase.

21-3

BUNTOVER (POWER PUSHOVER)As you learned in Chapter 16—GyroplaneAerodynamics, the stability of a gyroplane is greatlyinfluenced by rotor force. If rotor force is rapidlyremoved, some gyroplanes have a tendency to pitchforward abruptly. This is often referred to as a forwardtumble, buntover, or power pushover. Removing therotor force is often referred to as unloading the rotor,and can occur if pilot-induced oscillations becomeexcessive, if extremely turbulent conditions areencountered, or the nose of the gyroplane is pushed for-ward rapidly after a steep climb.

A power pushover can occur on some gyroplanes thathave the propeller thrust line above the center of grav-ity and do not have an adequate horizontal stabilizer. Inthis case, when the rotor is unloaded, the propellerthrust magnifies the pitching moment around the centerof gravity. Unless a correction is made, this nose pitching action could become self-sustaining andirreversible. An adequate horizontal stabilizer slows thepitching rate and allows time for recovery.

Since there is some disagreement between manufactur-ers as to the proper recovery procedure for this situation, you must check with the manufacturer ofyour gyroplane. In most cases, you need to removepower and load the rotor blades. Some manufacturers,especially those with gyroplanes where the propellerthrust line is above the center of gravity, recommend thatyou need to immediately remove power in order to pre-vent a power pushover situation. Other manufacturersrecommend that you first try to load the rotor blades. Forthe proper positioning of the cyclic when loading up therotor blades, check with the manufacturer.

When compared to other aircraft, the gyroplane is justas safe and very reliable. The most important factor, asin all aircraft, is pilot proficiency. Proper training andflight experience helps prevent the risks associatedwith pilot-induced oscillation or buntover.

GROUND RESONANCEGround resonance is a potentially damaging aerody-namic phenomenon associated with articulated rotorsystems. It develops when the rotor blades move out ofphase with each other and cause the rotor disc tobecome unbalanced. If not corrected, ground resonancecan cause serious damage in a matter of seconds.

Ground resonance can only occur while the gyroplaneis on the ground. If a shock is transmitted to the rotorsystem, such as with a hard landing on one gear orwhen operating on rough terrain, one or more of theblades could lag or lead and allow the rotor system’scenter of gravity to be displaced from the center of rota-tion. Subsequent shocks to the other gear aggravate the

imbalance causing the rotor center of gravity to rotatearound the hub. This phenomenon is not unlike an out-of-balance washing machine. [Figure 21-2]

To reduce the chance of experiencing ground reso-nance, every preflight should include a check forproper strut inflation, tire pressure, and lag-leaddamper operation. Improper strut or tire inflation canchange the vibration frequency of the airframe, whileimproper damper settings change the vibration fre-quency of the rotor.

If you experience ground resonance, and the rotorr.p.m. is not yet sufficient for flight, apply the rotorbrake to maximum and stop the rotor as soon as possi-ble. If ground resonance occurs during takeoff, whenrotor r.p.m. is sufficient for flight, lift off immediately.Ground resonance cannot occur in flight, and the rotorblades will automatically realign themselves once thegyroplane is airborne. When prerotating the rotor sys-tem prior to takeoff, a slight vibration may be felt thatis a very mild form of ground resonance. Should thisoscillation amplify, discontinue the prerotation andapply maximum rotor brake.

EMERGENCY APPROACH ANDLANDINGThe modern engines used for powering gyroplanes aregenerally very reliable, and an actual mechanical mal-function forcing a landing is not a common occurrence.Failures are possible, which necessitates planning forand practicing emergency approaches and landings.The best way to ensure that important items are notoverlooked during an emergency procedure is to use achecklist, if one is available and time permits. Mostgyroplanes do not have complex electrical, hydraulic,or pneumatic systems that require lengthy checklists.In these aircraft, the checklist can be easily committedto memory so that immediate action can be taken if

Rotor Center of Gravity

122°

122° 116°

Figure 21-2. Taxiing on rough terrain can send a shock waveto the rotor system, resulting in the blades of a three-bladedrotor system moving from their normal 120° relationship toeach other.

21-4

needed. In addition, you should always maintain anawareness of your surroundings and be constantly onthe alert for suitable emergency landing sites.

When an engine failure occurs at altitude, the firstcourse of action is to adjust the gyroplane’s pitch atti-tude to achieve the best glide speed. This yields themost distance available for a given altitude, which inturn, allows for more possible landing sites. A commonmistake when learning emergency procedures isattempting to stretch the glide by raising the nose,which instead results in a steep approach path at a slowairspeed and a high rate of descent. [Figure 21-3] Onceyou have attained best glide speed, scan the area withingliding distance for a suitable landing site. Rememberto look behind the aircraft, as well as in front, makinggentle turns, if necessary, to see around the airframe.When selecting a landing site, you must consider thewind direction and speed, the size of the landing site,obstructions to the approach, and the condition of thesurface. A site that allows a landing into the wind andhas a firm, smooth surface with no obstructions is themost desirable. When considering landing on a road, bealert for powerlines, signs, and automobile traffic. Inmany cases, an ideal site will not be available, and itwill be necessary for you to evaluate your options andchoose the best alternative. For example, if a steadywind will allow a touchdown with no ground roll, itmay be acceptable to land in a softer field or in a

smaller area than would normally be considered. Onlanding, use short or soft field technique, as appropri-ate, for the site selected. A slightly higher-than-normalapproach airspeed may be required to maintain ade-quate airflow over the rudder for proper yaw control.

EMERGENCY EQUIPMENT ANDSURVIVAL GEAROn any flight not in the vicinity of an airport, it ishighly advisable to prepare a survival kit with itemsthat would be necessary in the event of an emergency.A properly equipped survival kit should be able to provide you with sustenance, shelter, medical care, anda means to summon help without a great deal of efforton your part. An efficient way to organize your survivalkit is to prepare a basic core of supplies that would benecessary for any emergency, and allow additionalspace for supplementary items appropriate for the terrain and weather you expect for a particular flight.The basic items to form the basis of your survival kitwould typically include: a first-aid kit and field medical guide, a flashlight, water, a knife, matches,some type of shelter, and a signaling device. Additionalitems that may be added to meet the conditions, forexample, would be a lifevest for a flight over water, orheavy clothing for a flight into cold weather. Anotherconsideration is carrying a cellular phone. Severalpilots have been rescued after calling someone to indicate there had been an accident.

Best Glide Speed

Too Fast

Too

Slow

Figure 21-3. Any deviation from best glide speed will reduce the distance you can glide and may cause you to land short of asafe touchdown point.

22-1

As with any aircraft, the ability to pilot a gyroplanesafely is largely dependent on the capacity of the pilotto make sound and informed decisions. To this end,techniques have been developed to ensure that a pilotuses a systematic approach to making decisions, andthat the course of action selected is the most appropri-ate for the situation. In addition, it is essential that youlearn to evaluate your own fitness, just as you evaluatethe airworthiness of your aircraft, to ensure that yourphysical and mental condition is compatible with a safeflight. The techniques for acquiring these essentialskills are explained in depth in Chapter 14—Aeronautical Decision Making (Helicopter).

As explained in Chapter 14, one of the best methods todevelop your aeronautical decision making is learningto recognize the five hazardous attitudes, and how tocounteract these attitudes. [Figure 22-1] This chapterfocuses on some examples of how these hazardous atti-tudes can apply to gyroplane operations.

IMPULSIVITYGyroplanes are a class of aircraft which can be acquired,constructed, and operated in ways unlike most other air-craft. This inspires some of the most exciting andrewarding aspects of flying, but it also creates a uniqueset of dangers to which a gyroplane pilot must be alert.For example, a wide variety of amateur-built gyroplanesare available, which can be purchased in kit form and

assembled at home. This makes the airworthiness ofthese gyroplanes ultimately dependent on the vigilanceof the one assembling and maintaining the aircraft.Consider the following scenario.

Jerry recently attended an airshow that had a gyro-plane flight demonstration and a number of gyroplaneson display. Being somewhat mechanically inclined andretired with available spare time, Jerry decided thatbuilding a gyroplane would be an excellent project forhim and ordered a kit that day. When the kit arrived,Jerry unpacked it in his garage and immediately beganthe assembly. As the gyroplane neared completion,Jerry grew more excited at the prospect of flying an air-craft that he had built with his own hands. When thegyroplane was nearly complete, Jerry noticed that arudder cable was missing from the kit, or perhaps lostduring the assembly. Rather than contacting the manu-facturer and ordering a replacement, which Jerrythought would be a hassle and too time consuming, hewent to his local hardware store and purchased somecable he thought would work. Upon returning home, hewas able to fashion a rudder cable that seemed func-tional and continued with the assembly.

Jerry is exhibiting “impulsivity.” Rather than taking thetime to properly build his gyroplane to the specifica-tions set forth by the manufacturer, Jerry let his excitement allow him to cut corners by acting onimpulse, rather than taking the time to think the matterthrough. Although some enthusiasm is normal duringassembly, it should not be permitted to compromise theairworthiness of the aircraft. Manufacturers often usehigh quality components, which are constructed andtested to standards much higher than those found inhardware stores. This is particularly true in the area ofcables, bolts, nuts, and other types of fasteners wherestrength is essential. The proper course of action Jerryshould have taken would be to stop, think, and considerthe possible consequences of making an impulsivedecision. Had he realized that a broken rudder cable in flight could cause a loss of control ofthe gyroplane, he likely would have taken the time tocontact the manufacturer and order a cable that met thedesign specifications.

INVULNERABILITYAnother area that can often lead to trouble for a gyro-plane pilots is the failure to obtain adequate flight

HAZARDOUS ATTITUDE ANTIDOTE

Anti-authority: "Don't tell me!"

"Follow the rules. They are usually right."

Impulsivity: "Do something—quickly!" "Not so fast. Think first."

Invulnerability: "It won't happen to me!" "It could happen to me."

Macho: "I can do it." "Taking chances is foolish."

Resignation: "What's the use?"

"I'm not helpless. I can make the difference."

Figure 22-1. To overcome hazardous attitudes, you mustmemorize the antidotes for each of them. You should knowthem so well that they will automatically come to mind whenyou need them.

22-2

instruction to operate their gyroplane safely. This canbe the result of people thinking that because they canbuild the machine themselves, it must be simpleenough to learn how to fly by themselves. Other reasons that can lead to this problem can be simplymonetary, in not wanting to pay the money for adequateinstruction, or feeling that because they are qualified inanother type of aircraft, flight instruction is not neces-sary. In reality, gyroplane operations are quite unique,and there is no substitute for adequate training by acompetent and authorized instructor. Consider the following scenario.

Jim recently met a coworker who is a certified pilot andowner of a two-seat gyroplane. In discussing the gyro-plane with his coworker, Jim was fascinated andreminded of his days in the military as a helicopterpilot many years earlier. When offered a ride, Jim read-ily accepted. He met his coworker at the airport the following weekend for a short flight and was immedi-ately hooked. After spending several weeks researchingavailable designs, Jim decided on a particular gyroplane and purchased a kit. He had it assembled ina few months, with the help and advice of his new friendand fellow gyroplane enthusiast. When the gyroplanewas finally finished, Jim asked his friend to take himfor a ride in his two-seater to teach him the basics offlying. The rest, he said, he would figure out while flying his own machine from a landing strip that he hadfashioned in a field behind his house.

Jim is unknowingly inviting disaster by allowing him-self to be influenced by the hazardous attitude of“invulnerability.” Jim does not feel that it is possible tohave an accident, probably because of his past experi-ence in helicopters and from witnessing the ease withwhich his coworker controlled the gyroplane on theirflight together. What Jim is failing to consider, how-ever, is the amount of time that has passed since he wasproficient in helicopters, and the significant differencesbetween helicopter and gyroplane operations. He isalso overlooking the fact that his friend is a certificatedpilot, who has taken a considerable amount of instruc-tion to reach his level of competence. Without adequateinstruction and experience, Jim could, for example,find himself in a pilot-induced oscillation withoutknowing the proper technique for recovery, whichcould ultimately be disastrous. The antidote for an attitude of invulnerability is to realize that accidentscan happen to anyone.

MACHODue to their unique design, gyroplanes are quiteresponsive and have distinct capabilities. Althoughgyroplanes are capable of incredible maneuvers, theydo have limitations. As gyroplane pilots grow morecomfortable with their machines, they might be

tempted to operate progressively closer to the edge ofthe safe operating envelope. Consider the followingscenario.

Pat has been flying gyroplanes for years and has anexcellent reputation as a skilled pilot. He has recentlybuilt a high performance gyroplane with an advancedrotor system. Pat was excited to move into a moreadvanced aircraft because he had seen the same designperforming aerobatics in an airshow earlier that year.He was amazed by the capability of the machine. Hehad always felt that his ability surpassed the capabilityof the aircraft he was flying. He had invested a largeamount of time and resources into the construction ofthe aircraft, and, as he neared completion of the assem-bly, he was excited about the opportunity of showinghis friends and family his capabilities.

During the first few flights, Pat was not completelycomfortable in the new aircraft, but he felt that he wasprogressing through the transition at a much fasterpace than the average pilot. One morning, when he waswith some of his fellow gyroplane enthusiasts, Patbegan to brag about the superior handling qualities ofthe machine he had built. His friends were very excited,and Pat realized that they would be expecting quite ashow on his next flight. Not wanting to disappoint them,he decided that although it might be early, he wouldgive the spectators on the ground a real show. On hisfirst pass he came down fairly steep and fast and recov-ered from the dive with ease. Pat then decided to makeanother pass only this time he would come in muchsteeper. As he began to recover, the aircraft did notclimb as he expected and almost settled to the ground.Pat narrowly escaped hitting the spectators as he was trying to recover from the dive.

Pat had let the “macho” hazardous attitude influencehis decision making. He could have avoided the conse-quences of this attitude if he had stopped to think thattaking chances is foolish.

RESIGNATIONSome of the elements pilots face cannot be controlled.Although we cannot control the weather, we do havesome very good tools to help predict what it will do,and how it can affect our ability to fly safely. Goodpilots always make decisions that will keep theiroptions open if an unexpected event occurs while flying. One of the greatest resources we have in thecockpit is the ability to improvise and improve theoverall situation even when a risk element jeopardizesthe probability of a successful flight. Consider the fol-lowing scenario.

Judi flies her gyroplane out of a small grass strip onher family’s ranch. Although the rugged landscape ofthe ranch lends itself to the remarkable scenery, it

22-3

leaves few places to safely land in the event of an emer-gency. The only suitable place to land other than thegrass strip is to the west on a smooth section of the roadleading to the house. During Judi’s training, her trafficpatterns were always made with left turns. Figuringthis was how she was to make all traffic patterns, sheapplied this to the grass strip at the ranch. In addition,she was uncomfortable with making turns to the right.Since, the wind at the ranch was predominately fromthe south, this meant that the traffic pattern was to theeast of the strip.

Judi’s hazardous attitude is “resignation.” She hasaccepted the fact that her only course of action is to flyeast of the strip, and if an emergency happens, there isnot much she can do about it. The antidote to this hazardous attitude is “I’m not helpless, I can make a dif-ference.” Judi could easily modify her traffic pattern sothat she is always within gliding distance of a suitable landing area. In addition, if she was uncomfort-able with a maneuver, she could get additional training.

ANTI-AUTHORITYRegulations are implemented to protect aviation personnel as well as the people who are not involved inaviation. Pilots who choose to operate outside of the

regulations, or on the ragged edge, eventually getcaught, or even worse, they end up having an accident.Consider the following scenario.

Dick is planning to fly the following morning and real-izes that his medical certificate has expired. He knowsthat he will not have time to take a flight physicalbefore his morning flight. Dick thinks to himself “Therules are too restrictive. Why should I spend the timeand money on a physical when I will be the only one atrisk if I fly tomorrow?”

Dick decides to fly the next morning thinking that noharm will come as long as no one finds out that he isflying illegally. He pulls his gyroplane out from thehangar, does the preflight inspection, and is gettingready to start the engine when an FAA inspector walksup and greets him. The FAA inspector is conducting arandom inspection and asks to see Dick’s pilot andmedical certificates.

Dick subjected himself to the hazardous attitude of “anti-authority.” Now, he will be unable to fly, and has invitedan exhaustive review of his operation by the FAA. Dickcould have prevented this event if had taken the time tothink, “Follow the rules. They are usually right.”

G-1

ABSOLUTE ALTITUDE—The act-ual distance an object is above theground.

ADVANCING BLADE—The blademoving in the same direction as thehelicopter or gyroplane. In rotorcraftthat have counterclockwise main rotorblade rotation as viewed from above,the advancing blade is in the right halfof the rotor disc area during forwardmovement.

AIRFOIL—Any surface designed toobtain a useful reaction of lift, or neg-ative lift, as it moves through the air.

AGONIC LINE—A line along whichthere is no magnetic variation.

AIR DENSITY—The density of theair in terms of mass per unit volume.Dense air has more molecules per unitvolume than less dense air. The densi-ty of air decreases with altitude abovethe surface of the earth and withincreasing temperature.

AIRCRAFT PITCH—When refer-enced to an aircraft, it is the move-ment about its lateral, or pitch axis.Movement of the cyclic forward or aftcauses the nose of the helicopter orgyroplane to pitch up or down.

AIRCRAFT ROLL—Is the move-ment of the aircraft about its longitudinal axis. Movement of thecyclic right or left causes the helicop-ter or gyroplane to tilt in that direction.

AIRWORTHINESS DIRECTIVE—When an unsafe condition existswith an aircraft, the FAA issues an air-worthiness directive to notify con-cerned parties of the condition and todescribe the appropriate correctiveaction.

ALTIMETER—An instrument thatindicates flight altitude by sensingpressure changes and displaying alti-tude in feet or meters.

ANGLE OF ATTACK—The anglebetween the airfoil’s chord line andthe relative wind.

ANTITORQUE PEDAL—The pedalused to control the pitch of the tailrotor or air diffuser in a NOTAR®system.

ANTITORQUE ROTOR—See tailrotor.

ARTICULATED ROTOR—A rotorsystem in which each of the blades isconnected to the rotor hub in such away that it is free to change its pitchangle, and move up and down andfore and aft in its plane of rotation.

AUTOPILOT—Those units andcomponents that furnish a means ofautomatically controlling the aircraft.

AUTOROTATION—The conditionof flight during which the main rotoris driven only by aerodynamic forceswith no power from the engine.

AXIS-OF-ROTATION—The imagi-nary line about which the rotorrotates. It is represented by a linedrawn through the center of, and per-pendicular to, the tip-path plane.

BASIC EMPTY WEIGHT—Theweight of the standard rotorcraft,operational equipment, unusable fuel,and full operating fluids, includingfull engine oil.

BLADE CONING—An upwardsweep of rotor blades as a result of liftand centrifugal force.

BLADE DAMPER—A deviceattached to the drag hinge to restrainthe fore and aft movement of the rotorblade.

BLADE FEATHER OR FEATH-ERING—The rotation of the bladearound the spanwise (pitch change)axis.

BLADE FLAP—The ability of therotor blade to move in a vertical direc-tion. Blades may flap independentlyor in unison.

BLADE GRIP—The part of the hubassembly to which the rotor blades areattached, sometimes referred to asblade forks.

BLADE LEAD OR LAG—The foreand aft movement of the blade in theplane of rotation. It is sometimescalled hunting or dragging.

BLADE LOADING—The loadimposed on rotor blades, determinedby dividing the total weight of the hel-icopter by the combined area of all therotor blades.

BLADE ROOT—The part of theblade that attaches to the blade grip.

BLADE SPAN—The length of ablade from its tip to its root.

BLADE STALL—The condition ofthe rotor blade when it is operating atan angle of attack greater than themaximum angle of lift.

BLADE TIP—The further most partof the blade from the hub of the rotor.

BLADE TRACK—The relationshipof the blade tips in the plane of rota-tion. Blades that are in track will movethrough the same plane of rotation.

BLADE TRACKING—The mechan-ical procedure used to bring the bladesof the rotor into a satisfactory relation-ship with each other under dynamicconditions so that all blades rotate on acommon plane.

BLADE TWIST—The variation inthe angle of incidence of a bladebetween the root and the tip.

BLOWBACK—The tendency of therotor disc to tilt aft in forward flight asa result of flapping.

GLOSSARY

G-2

BUNTOVER—The tendency of agyroplane to pitch forward when rotorforce is removed.

CALIBRATED AIRSPEED (CAS)—Indicated airspeed of an aircraft,corrected for installation and instru-mentation errors.

CENTER OF GRAVITY—The the-oretical point where the entire weightof the helicopter is considered to beconcentrated.

CENTER OF PRESSURE—Thepoint where the resultant of all theaerodynamic forces acting on an air-foil intersects the chord.

CENTRIFUGAL FORCE—Theapparent force that an object movingalong a circular path exerts on thebody constraining the object and thatacts outwardly away from the centerof rotation.

CENTRIPETAL FORCE—Theforce that attracts a body toward itsaxis of rotation. It is opposite centrifu-gal force.

CHIP DETECTOR—A warningdevice that alerts you to any abnormalwear in a transmission or engine. Itconsists of a magnetic plug locatedwithin the transmission. The magnetattracts any metal particles that havecome loose from the bearings or othertransmission parts. Most chip detec-tors have warning lights located on theinstrument panel that illuminate whenmetal particles are picked up.

CHORD—An imaginary straight linebetween the leading and trailing edgesof an airfoil section.

CHORDWISE AXIS—A term usedin reference to semirigid rotorsdescribing the flapping or teeteringaxis of the rotor.

COAXIL ROTOR—A rotor systemutilizing two rotors turning in oppositedirections on the same centerline. Thissystem is used to eliminated the needfor a tail rotor.

COLLECTIVE PITCH CON-TROL—The control for changing thepitch of all the rotor blades in the mainrotor system equally and simultane-ously and, consequently, the amountof lift or thrust being generated.

CONING—See blade coning.

CORIOLIS EFFECT—The tenden-cy of a rotor blade to increase ordecrease its velocity in its plane ofrotation when the center of massmoves closer or further from the axisof rotation.

CYCLIC FEATHERING—Themechanical change of the angle ofincidence, or pitch, of individual rotorblades independently of other bladesin the system.

CYCLIC PITCH CONTROL—Thecontrol for changing the pitch of eachrotor blade individually as it rotatesthrough one cycle to govern the tilt ofthe rotor disc and, consequently, thedirection and velocity of horizontalmovement.

DELTA HINGE—A flapping hingewith a skewed axis so that the flappingmotion introduces a component offeathering that would result in a restor-ing force in the flap-wise direction.

DENSITY ALTITUDE—Pressurealtitude corrected for nonstandardtemperature variations.

DEVIATION—A compass errorcaused by magnetic disturbances fromthe electrical and metal components inthe aircraft. The correction for thiserror is displayed on a compass cor-rection card place near the magneticcompass of the aircraft.

DIRECT CONTROL—The abilityto maneuver a rotorcraft by tilting therotor disc and changing the pitch ofthe rotor blades.

DIRECT SHAFT TURBINE—Ashaft turbine engine in which the com-pressor and power section are mount-ed on a common driveshaft.

DISC AREA—The area swept by theblades of the rotor. It is a circle withits center at the hub and has a radius ofone blade length.

DISC LOADING—The total heli-copter weight divided by the rotor discarea.

DISSYMMETRY OF LIFT—Theunequal lift across the rotor discresulting from the difference in thevelocity of air over the advancingblade half and retreating blade half ofthe rotor disc area.

DRAG—An aerodynamic force on abody acting parallel and opposite torelative wind.

DUAL ROTOR—A rotor system uti-lizing two main rotors.

DYNAMIC ROLLOVER—The ten-dency of a helicopter to continuerolling when the critical angle isexceeded, if one gear is on the ground,and the helicopter is pivoting aroundthat point.

FEATHERING—The action thatchanges the pitch angle of the rotorblades by rotating them around theirfeathering (spanwise) axis.

FEATHERING AXIS—The axisabout which the pitch angle of a rotorblade is varied. Sometimes referred toas the spanwise axis.

FEEDBACK—The transmittal offorces, which are initiated by aerody-namic action on rotor blades, to thecockpit controls.

FLAPPING HINGE—The hingethat permits the rotor blade to flap andthus balance the lift generated by theadvancing and retreating blades.

FLAPPING—The vertical move-ment of a blade about a flappinghinge.

FLARE—A maneuver accomplishedprior to landing to slow down a rotor-craft.

G-3

FREE TURBINE—A turboshaftengine with no physical connectionbetween the compressor and poweroutput shaft.

FREEWHEELING UNIT—A com-ponent of the transmission or powertrain that automatically disconnectsthe main rotor from the engine whenthe engine stops or slows below theequivalent rotor r.p.m.

FULLY ARTICULATED ROTORSYSTEM—See articulated rotor sys-tem.

GRAVITY—See weight.

GROSS WEIGHT—The sum of thebasic empty weight and useful load.

GROUND EFFECT—A usuallybeneficial influence on rotorcraft per-formance that occurs while flyingclose to the ground. It results from areduction in upwash, downwash, andbladetip vortices, which provide a cor-responding decrease in induced drag.

GROUND RESONANCE—Self-excited vibration occurring wheneverthe frequency of oscillation of theblades about the lead-lag axis of anarticulated rotor becomes the same asthe natural frequency of the fuselage.

G Y R O C O P T E R — Tr a d e m a r kapplied to gyroplanes designed andproduced by the Bensen AircraftCompany.

GYROSCOPIC PRECESSION—An inherent quality of rotating bodies,which causes an applied force to bemanifested 90° in the direction ofrotation from the point where theforce is applied.

HUMAN FACTORS—The study ofhow people interact with their environment. In the case of generalaviation, it is the study of how pilotperformance is influenced by suchissues as the design of cockpits, thefunction of the organs of the body, theeffects of emotions, and the interac-

tion and communication with otherparticipants in the aviation communi-ty, such as other crew members and airtraffic control personnel.

HUNTING—Movement of a bladewith respect to the other blades in theplane of rotation, sometimes calledleading or lagging.

INERTIA—The property of matterby which it will remain at rest or in astate of uniform motion in the samedirection unless acted upon by someexternal force.

IN GROUND EFFECT (IGE)HOVER—Hovering close to the sur-face (usually less than one rotor diam-eter distance above the surface) underthe influence of ground effect.

INDUCED DRAG—That part of thetotal drag that is created by the pro-duction of lift.

INDUCED FLOW—The componentof air flowing vertically through therotor system resulting from the pro-duction of lift.

ISOGONIC LINES—Lines oncharts that connect points of equalmagnetic variation.

KNOT—A unit of speed equal to onenautical mile per hour.

L/DMAX—The maximum ratio

between total lift (L) and total drag(D). This point provides the best glidespeed. Any deviation from the bestglide speed increases drag and reducesthe distance you can glide.

LATERIAL VIBRATION—A vibra-tion in which the movement is in a lat-eral direction, such as imbalance of themain rotor.

LEAD AND LAG—The fore (lead)and aft (lag) movement of the rotorblade in the plane of rotation.

LICENSED EMPTY WEIGHT—Basic empty weight not including fullengine oil, just undrainable oil.

LIFT—One of the four main forcesacting on a rotorcraft. It acts perpendi-cular to the relative wind.

LOAD FACTOR—The ratio of aspecified load to the total weight ofthe aircraft.

MARRIED NEEDLES—A termused when two hands of an instrumentare superimposed over each other, ason the engine/rotor tachometer.

MAST—The component that sup-ports the main rotor.

MAST BUMPING—Action of therotor head striking the mast, occurringon underslung rotors only.

MINIMUM LEVEL FLIGHTSPEED—The speed below which agyroplane, the propeller of which isproducing maximum thrust, loses alti-tude.

NAVIGATIONAL AID (NAVAID)—Any visual or electronic device, air-borne or on the surface, that providespoint-to-point guidance information,or position data, to aircraft in flight.

NIGHT—The time between the endof evening civil twilight and thebeginning of morning civil twilight, aspublished in the American AirAlmanac.

NORMALLY ASPIRATED ENGINE—An engine that does not compen-sate for decreases in atmospheric pres-sure through turbocharging or othermeans.

ONE-TO-ONE VIBRATION—Alow frequency vibration having onebeat per revolution of the rotor. Thisvibration can be either lateral, vertical,or horizontal.

OUT OF GROUND EFFECT(OGE) HOVER—Hovering greaterthan one diameter distance above thesurface. Because induced drag isgreater while hovering out of groundeffect, it takes more power to achievea hover out of ground effect.

G-4

PARASITE DRAG—The part oftotal drag created by the form or shapeof helicopter parts.

PAYLOAD—The term used for pas-sengers, baggage, and cargo.

PENDULAR ACTION—The lateralor longitudinal oscillation of the fuse-lage due to it being suspended fromthe rotor system.

PITCH ANGLE—The angle betweenthe chord line of the rotor blade andthe reference plane of the main rotorhub or the rotor plane of rotation.

PREROTATION—In a gyroplane, itis the spinning of the rotor to a suffi-cient r.p.m. prior to flight.

PRESSURE ALTITUDE—The heightabove the standard pressure level of29.92 in. Hg. It is obtained by setting29.92 in the barometric pressure win-dow and reading the altimeter.

PROFILE DRAG—Drag incurredfrom frictional or parasitic resistanceof the blades passing through the air. Itdoes not change significantly with theangle of attack of the airfoil section,but it increases moderately as airspeedincreases.

RESULTANT RELATIVE WIND—Airflow from rotation that is modifiedby induced flow.

RETREATING BLADE—Any blade,located in a semicircular part of the rotordisc, where the blade direction is oppo-site to the direction of flight.

RETREATING BLADE STALL—A stall that begins at or near the tip ofa blade in a helicopter because of thehigh angles of attack required to com-pensate for dissymmetry of lift. In agyroplane the stall occurs at 20 to 40percent outboard from the hub.

RIGID ROTOR—A rotor systempermitting blades to feather but notflap or hunt.

ROTATIONAL VELOCITY—Thecomponent of relative wind producedby the rotation of the rotor blades.

ROTOR—A complete system ofrotating airfoils creating lift for a heli-copter or gyroplane.

ROTOR DISC AREA—See diskarea.

ROTOR BRAKE—A device used tostop the rotor blades during shutdown.

ROTOR FORCE—The force pro-duced by the rotor in a gyroplane. It iscomprised of rotor lift and rotor drag.

SEMIRIGID ROTOR—A rotor sys-tem in which the blades are fixed to thehub but are free to flap and feather.

SETTLING WITH POWER—Seevortex ring state.

SHAFT TURBINE—A turbineengine used to drive an output shaftcommonly used in helicopters.

SKID—A flight condition in whichthe rate of turn is too great for theangle of bank.

SKID SHOES—Plates attached tothe bottom of skid landing gear pro-tecting the skid.

SLIP—A flight condition in whichthe rate of turn is too slow for theangle of bank.

SOLIDITY RATIO—The ratio ofthe total rotor blade area to total rotordisc area.

SPAN—The dimension of a rotorblade or airfoil from root to tip.

SPLIT NEEDLES—A term used todescribe the position of the two nee-dles on the engine/rotor tachometerwhen the two needles are not superim-posed.

STANDARD ATMOSPHERE—Ahypothetical atmosphere based onaverages in which the surface temper-ature is 59°F (15°C), the surface pres-sure is 29.92 in. Hg (1013.2 Mb) atsea level, and the temperature lapserate is approximately 3.5°F (2°C) per1,000 feet.

STATIC STOP—A device used tolimit the blade flap, or rotor flap, atlow r.p.m. or when the rotor isstopped.

STEADY-STATE FLIGHT—A con-dition when a rotorcraft is in straight-and-level, unaccelerated flight, and allforces are in balance.

SYMMETRICAL AIRFOIL—Anairfoil having the same shape on thetop and bottom.

TAIL ROTOR—A rotor turning in aplane perpendicular to that of the mainrotor and parallel to the longitudinalaxis of the fuselage. It is used to con-trol the torque of the main rotor and toprovide movement about the yaw axisof the helicopter.

TEETERING HINGE—A hingethat permits the rotor blades of a semi-rigid rotor system to flap as a unit.

THRUST—The force developed bythe rotor blades acting parallel to therelative wind and opposing the forcesof drag and weight.

TIP-PATH PLANE—The imaginarycircular plane outlined by the rotorblade tips as they make a cycle ofrotation.

TORQUE—In helicopters with a sin-gle, main rotor system, the tendency ofthe helicopter to turn in the oppositedirection of the main rotor rotation.

TRAILING EDGE—The rearmostedge of an airfoil.

TRANSLATING TENDENCY—The tendency of the single-rotor heli-copter to move laterally during hover-ing flight. Also called tail rotor drift.

G-5

TRANSLATIONAL LIFT—Theadditional lift obtained when enteringforward flight, due to the increasedefficiency of the rotor system.

T R A N S V E R S E - F L O WEFFECT—A condition of increaseddrag and decreased lift in the aft por-tion of the rotor disc caused by the airhaving a greater induced velocity andangle in the aft portion of the disc.

TRUE ALTITUDE—The actualheight of an object above mean sealevel.

TURBOSHAFT ENGINE—A tur-bine engine transmitting powerthrough a shaft as would be found in aturbine helicopter.

TWIST GRIP—The power controlon the end of the collective control.

UNDERSLUNG—A rotor hub thatrotates below the top of the mast, ason semirigid rotor systems.

UNLOADED ROTOR—The state ofa rotor when rotor force has beenremoved, or when the rotor is operatingunder a low or negative G condition.

USEFUL LOAD—The differencebetween the gross weight and thebasic empty weight. It includes theflight crew, usable fuel, drainable oil,if applicable, and payload.

VARIATION—The angular differ-ence between true north and magneticnorth; indicated on charts by isogoniclines.

VERTICAL VIBRATION—A vibra-tion in which the movement is up anddown, or vertical, as in an out-of-trackcondition.

VORTEX RING STATE—A tran-sient condition of downward flight(descending through air after just pre-viously being accelerated downwardby the rotor) during which an appre-ciable portion of the main rotor sys-tem is being forced to operate atangles of attack above maximum.Blade stall starts near the hub and pro-gresses outward as the rate of descentincreases.

WEIGHT—One of the four mainforces acting on a rotorcraft.Equivalent to the actual weight of therotorcraft. It acts downward towardthe center of the earth.

YAW—The movement of a rotorcraftabout its vertical axis.

Collision Avoidance at Night13-515-2 When direct controlof the rotor head was perfected, the jump...

Documents

Transcript of Collision Avoidance at Night13-515-2 When direct controlof the rotor head was perfected, the jump...