aircraft dynamics

7/29/2019 aircraft dynamics

1/54

BASIC AERODYNAMICS(aerodinmica bsica)

February 28, 2007

School of

Missionary Aviation TechnologyLowell, MI


2/54

Aerodynamics Defined Aero is from aer air , Greek 1000 B.C.

Dynamics - the study of motion

Aerodynamic

The scientific study of the movement of air or other gases relativeto stationary or moving solid bodies immersed in them,AIRPLANES IN THE SKY!

Aerodynamics

The qualities required for fast and efficient movement through theair.


3/54

Objective Exhibit correlative knowledge of the

basics of aerodynamics, as it relates to

Airfoil design characteristics, stabilityand controllability, and primary flightcontrols.

Pretty much know where things are, aswell as why and how they are there.


4/54

Before we go any farther!

Allow me to introduce the true pioneerand Padre de Aviacion.(father of

Aviation)..


5/54


6/54


7/54


8/54


9/54


10/54

The Basics Thrust: Propeller

(Rotor Blade)

A Mexican in the Military!


11/54

Aircraft SectionsFuselage houses Cockpit& Engine on single engine A/C


12/54

Aircraft Sections


13/54

Airfoils

(plano aerodinmico) What is an airfoil?

Any surface designed to obtain a useful action, orlift, from air passing over it.,i.e. WING, propeller,

rotor blade Airfoil Terminology

Camber: Amount of curve in an aerodynamic section.Measured in % chord.

Chord Line:Imaginary line drawn from leading edge totrailing edge.

Mean Camber line:Line drawn midway between theupper and lower surfaces.


14/54

Airfoils

(plano aerodinmico)


15/54


16/54


17/54

Airfoils

(plano aerodinmico) Cambered airfoils produced lift at zero

angle of attack.

Symmetric (no camber) airfoils do notproduce lift at zero angle of attack


18/54

What happens during a

stall?

Flow over the top surface separates from the airfoil,

resulting in a high pressure wake region


19/54

Dihedral Angle formed between a/c lateral axis

and line which passes through the

center of the wing.


20/54

Airfoils NASAs FoilSim II airfoil simulation

program: (see link in online classroom)


21/54


22/54

Wings (Alas) Elliptical Wing

Costly $$$$$

Good LoadDistribution

Gs

Even stall

dispersing


23/54

Wings (Alas) Rectangular Wing

Inexpensive

Low load capability Low Speeds

Stall inboard 1/3


24/54

Wings (Alas) Tapered

Great Load Distribution

Stall Inboard section1/2


25/54

Wings (Alas) Delta

Supersonic Flight


26/54

Flight Controls Aileron

causes rotation about the longitudinal axis.


27/54

Flight Controls Elevator: controls up/down movement.

Control about lateral axis.

Stabilator: single piece

control surface. Acts as

horizontal stabilizer and

Elevator. (Piper 140)


28/54

Flight Controls Remember an Elevator creates

negative or downward lift!


29/54

Flight Controls Rudder:mounted on vertical stabilizer.

Controls movement about vertical axis,

yaw.


30/54


31/54

Flight Controls Flaps

Plain: trailing edge hinged

Split: part of underside trailing edge splitsand folds

Slotted: forms slot between leading edgeand flap well. Increases lift as air flows

over flap. Fowler: extends on tracks. Increase wing

area and camber


32/54

Flight Controls Speed Brakes: Produce drag without

affecting lift or pitching tendency. No

rotation about axis.


33/54

Flight Controls Winglets:Out-of-plane

surface extending from lifting

surface. Reduces wingtip

vortex formation (and thus

induced drag).


34/54

Flight ControlsCanard: Horizontal lifting control mounted

in front of main lifting plane.


35/54

Landing Gear Supports a/c when not flying

Provides shock absorption for landing.


36/54


37/54


38/54


39/54


40/54


41/54


42/54


43/54


44/54


45/54


46/54

Forces of Flight Lift = Wings/airflow

Weight = Aircraft

Thrust = Powerplant / Propeller Drag = Bi - product if lift

Parasite: friction of air moving over structure,varied with speed

Induced: Varies with speed. Force componentparallel to free stream. Due to development of lift.


47/54

Forces of Flight Di: Induced Drag

Di = (Cdi)(q)(S) Di=induced drag, lbs

q=dynamic pressure, psf Cdi=induced drag coefficient

Cl X sin Xangle I (induced)

S=wing area, sq ft.

So here we see Di is a biproduct of Lift.

Future engineers, this is for you!

*Cl is the ratio between lift pressure and dynamic pressure


48/54

Forces of Flight Airplane Axis

Elevator =

Lateral, Pitch

Ailerons =

Longitudinal, Roll

Rudder =

Vertical Yaw


49/54


50/54

Forces of Flight Equilibrium: Balanced forces

Static Stability: initial tendency afterdisturbance

Positive static stability: initial tendency toreturn to equilibrium after disturbance.

Negative static: initial tendency to continue

away from equilibrium after disturbance Neutral Static stability: initial tendency to

remain in new condition after disturbance


51/54


52/54


53/54


54/54

aircraft dynamics

Documents

Transcript of aircraft dynamics