The History of VTOL

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The LTV XCCC-142 had a maximum speed offfover 400mppph, making it one of the fastesttt

VTOL transport aircraft of the era, but it neverrrprogressed beyooond the prototype stage after aaatri-services mannnagement team could not see aaa

requiremeeent for a V/STOL transport USAF

The concept of aVertical Take Off& Landing (VTOL) aircraft canbe traced back as far as 1480,however Leonardo daVinci’s

‘aerial screw’ designs are not thought tohave progressed beyond the drawing board.

In 1907, French inventor Paul Cornu’shelicopter lifted 1ft above the groundto make the first pilotedVTOL flight.Using two 20ft counter-rotating rotorsdriven by a 24hp Antoinette engine,the craft was heavy and unstable andthe project was quickly abandoned.

World WarTwo saw both Germany andthe Allies using helicopters and autogyrosto a limited degree but it was Germany’sscientists who sought to createVTOL-capable warplanes during the final phase ofthe conflict. Erich Bachem’s BP-20 ‘Natter’design was a wooden, rocket-poweredtail-sitting attack aircraft (a tail-sitter takesoff and lands vertically on its tail, thentilts horizontally for forward flight),TheNatter would be guided towards the Alliedbombers by an autopilot; a pilot would thentake over to aim and fire the salvo of rocketsmounted in the nose. Pilot and airframewould land using separate parachutes,while the nose section was disposable. On

VERTICAL REALITY

The ability to operate withhhout a runway was considereeed of greatstrategic importance durinnng the ColdWar but few mannnufacturersmanaged to perffrfect the teccchnologyygy,as Steve Bridgewater explains

March 1, 1945, the only manned verticaltake-off fllflight ended in the death of thetest pilot, Lothar Sieber and the end ofthe war stopped further development.

The Focke-Wulf Triebflügel (translatingto ‘thrust-wing hunter’) was a tail-sittingfighter concept that could launch vertically

for the defence of factories or cities.TheTriebfllflügel had nnno wings and all the lifttft andthrust was provided by a rotor/propellerassembly a third of the way down the sideof the aircraft. In a vertical position, therotors would have functioned similarly toa helicopter but when in horizontal flight

The history ooof VTTVTOL

MILITARY HISTORY VTOL

The USA, USSR and Germany explored theZero-Length Launch System concept duringthe 1950s. Here an F-100 Super Sabre islaunched off a rocket rail during flight testing

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propellers attached to a 5,500shp AllisonYT40-A-16 turboprop and was intendedto be a high-performance fighter aircraftcapable of operating from small warships.

Lockheed’s aircraft was of similarconfiguration but was only flownin ‘conventional’ style with a largeundercarriage fitted to enable to it tooperate from a runway.The proposed7,100shp AllisonYT40-A-14 nevermaterialised and the 5,300shp version didn’tgive the 16,220lb aircraft aVTOL capability– although it was successfully hovered.Furthermore, only the most gifted pilotwould be able to look over his shoulderto ‘reverse’ onto the XFV’s landing pad!

Ryan Aeronautical took turboproptechnology a step further with its jet-powered X-13Vertijet, which first flewon December 10, 1955.TheVertijetwas 23ft 5in long; just large enough toaccommodate a single pilot and a 10,000lb/thrust Rolls-Royce Avon turbojet.Thehigh mounted delta wing had a 21ftwingspan and hover control came froma mixture of vectored thrust (for pitchand yaw) and ‘puffer’ jets (for roll).

The aircraft first flew in ‘conventional’form thanks to temporary landing gear andlater demonstrated its ability to hover and

they would function more like a giantpropeller.At the end of each blade was aramjet and the blade’s pitch would changeto alter speed and lift.The Germans hadonly reached the wind-tunnel testingstage before the end of the war andnone of the Allied forces saw sufficientpotential to continue the project!

Rocket AssistedTake Off (RATO)would become commonplace in thepost-war era, but with the Cold Warraging, air arms were acutely aware ofthe aeroplane’s biggest Achilles’ Heel… itneeded a runway from which to operate.

Zero lengthIn 1953, the USA, USSR and post-warGermany explored the novel Zero-LengthLaunch System. Designed by the Martincompany in the USA and trialled on theF-84Thunderjet, the aircraft was acceleratedoff a mobile launch platform ramp at up to175mph by a series of rockets, after whichit would be above its stall speed and ableto fly of its own accord.Trials also includedthe F-100 Super Sabre and Luftwaffe F-104Starfighter and the USSR undertook similarexperiments with the MiG-19 Farmer.However, although the system worked, itwas discovered that the launch platformswere expensive to operate and bulky totransport – plus, of course, the aircraftstill needed a runway to land on! Theincreased efficiency of guided missiles alsoresulted in the project being scrapped.

Tail-sittersGermany’s tail-sitting concept was revisitedin both the USA and France in the 1950s,with limited degrees of success - theFrench producing the SNECMA C.450Coléoptère.This was a single-seat aircraftdeveloped from SNECMA’s AtarVolantwingless test rig, which effectively sawa pilot sitting atop a large engine!

The Coléoptère had a central core similarto the AtarVolant but was surrounded byan annular (circular) wing.The pilot nowsat in an enclosed cockpit fitted with anejection seat and test pilot Auguste Moreltook the sole Coléoptère into the air forthe first time on May 6, 1959. On the ninthflight it was planned to make a transitionto the first horizontal flight but with limitedinstruments, Morel became disorientatedand the aircraft tilted too much. He ejectedat 500ft and was badly injured.The projectwas terminated with immediate effect.

In 1954, the USA explored the tail-sittingconcept with the Lockheed XFV and theConvair XFY Pogo – albeit with turboproppower instead of pure jets.The Pogo (Ed:see the Jul/Aug 2013 issue of Jets for anin depth article on the aircraft) had deltawings and three-bladed contra-rotating

Lockheed XFV (left) and the Convair XFY Pogo both flew in 1954 and explored the tail-sittingconcept – albeit with turboprop power instead of pure jets

The SNECMA C.450 Coléoptère had acentral core similar to the Atar Volant butwas surrounded by an annular wing. On theninth flight the pilot became disorientatedand the aircraft tilted too much. He ejectedbut was badly injured.The project wasterminated with immediate effect

The Bachem’s BP-20 ‘Natter’ was one of themore advanced VTOL concepts to come out ofNazi Germany during World WarTwo

Pioneering British VTOL designs, theRolls-RoyceThrust Measuring Rig (‘FlyingBedstead’) and the Short SC.1 (right) pavedthe way for the Harrier



transition from horizontal to vertical flight.On April 11, 1957 the second prototypebecame the first X-13 to take off fromthe vertically raised platform, transition tohorizontal flight and then land back againon the platform vertically – which could belowered horizontally and used as a trailer.

In July of the same year, the aircraft causeda great stir by landing at the Pentagonin Washington DC, but sadly the USAFchose not to continue development of theVertijet as it could not see an operationalrequirement for such technology.

Lift jetsMeanwhile, other parts of the world wereexploring lift jet technology to provide anaircraft with aerostatic lift instead of – orin addition to – thrust.Aerostatic lift is liftcreated without the movement of air overan airfoil (such as a wing) and on aVTOLaircraft, lift jets can either be the mainpowerplant (such as on the Harrier) orinstalled as auxiliary engines purely for lift.

Once again, the concept can be tracedback to German engineers in World WarTwo but the technology did not see serviceuntil the 1950s. Perhaps the most famousemployment of the lift jet principle was inthe Rolls-RoyceThrust Measuring Rig (TMR)– better known as the ‘Flying Bedstead.’

Designed primarily by Dr Alan Griffith,who had worked on gas turbine designat the Royal Aircraft Establishment (RAE)since the 1920s, the Flying Bedstead [Ed:see Jets Sept/Oct 2014 for a full article]possessed no inherent stability andused jet efflux to maintain position.

One engine exhausted downwardsthrough a central nozzle to provide lift whilea second engine discharged through twosmaller nozzles.The rig had four outriggerarms, through which compressed air waspumped to control roll, pitch and yaw.

TheTMR was purely experimentaland first flew from Hucknall aerodromein Nottingham on July 3, 1953. Lack ofpower meant the craft was difficult to flyand on September 16, 1957 it crashedwhen the thrust vectoring system failed;fortunately, pilot Stan Hubbard survived.Wing Commander Larsen, flying the secondTMR, was not so lucky on November 29

of the same year and lost his life during hisfirst attempt at piloting the Flying Bedstead.

In its four-year career theTMR hadprovided Rolls-Royce with valuableinformation and led to the developmentof the RB.108 direct-lift turbojet engine;five of which were used to power the first

true BritishVTOL aircraft; the Short SC.1.The SC.1 was designed to meet a

Ministry of Supply (MoS) request for tenderfor a vertical take-off research aircraft andultimately emerged as a single-seat lowwing, tailless, delta-winged aeroplane.

The SC.1 used four of the RB.108engines in a vertical format for lift and asingle example mounted in the rear ofthe airframe for forward flight.The liftengines could be swivelled transversely andwere therefore able to produce vectoredthrust for acceleration/deceleration.

Around 10% of the air from the engineswas bled off to feed variable nose, tailand wingtip jets, providing pitch, roll andyaw control at low speeds – when therewas insufficient airflow over the controlsurfaces for conventional control.The SC.1was also fitted with the first fly-by-wirecontrol system used on aVTOL aircraftand this aided ‘fly-ability’ considerablywhen it first flew on April 2, 1957.

The two SC.1s flew for more than adecade and although one crashed in Belfaston October 2, 1963, killing the pilot, theaircraft was rebuilt for further testing.The

“The Flying Bedsteadpossessed no inherentstability and used jet

efflux to maintainposition”

The Ryan X-13 Vertijet had a hook on theunderside used to hang the aircraft from thevertical landing platform.After the aircrafthad ‘alighted’ vertically, the platform couldbe lowered to horizontal and then used totransport the aircraft on the ground as a trailer

The Mirage IIIV eventually attained Mach 2.04in level flight but was never able to take offvertically and successfully go supersonic in thesame sortie

The Yakovlev Yak-36 Freehand was used by theUSSR as a VTOL technology demonstrator.The aircraft hovered for the first time onJanuary 9, 1963 but the aircraft was plaguedwith problems with hot gas re-ingestion whereexhaust gasses were sucked back into theintakes causing a loss of thrust

The British Fairey Rotodyne featureda tip-jet-powered rotor that burneda mixture of fuel and compressed airbled from two wing-mounted NapierEland turboprops.The rotor was drivenfor vertical take-off and landing butcreated a phenomenal amount of noise– which eventually contributed to theproject’s cancellation


data obtained from the SC.1 programmewould prove invaluable to the ‘puffer jet’system used on the Hawker SiddeleyP.1127 and the later Harrier [Ed: see p34].

European effortsIn Germany,Vereinigte FlugtechnischeWerke (VFW) created theVAK 191Bas an experimental aircraft to test thetechnologies needed to create aVTOLreplacement for the Fiat G.91 fighter.Propulsion was provided by both a10,500lb/thrust Rolls-Royce RB.193-12 turbojet – which provided both liftand propulsion by virtue of its vectoredthrust capability – and two 5,587lb/thrustRolls-Royce RB.162 vertical lift engines.

Three examples were built and thefirst hovering flight was made in Bremenon September 20, 1971.Transition fromvertical flight to horizontal and back againwas achieved on October 26, 1972 andthe three aircraft had performed 91 flightsby the time the project ended in 1975.

Although it did not lead to aVTOLfighter, theVAK 191B was used totest some of the concepts for theEuropean MRCA programme –which led to the PanaviaTornado.

The French also toyed with the liftengine principle and Dassault created theone-off BalzacV in the early 1960s totest the configuration for the proposedVTOL Mirage IIIV. Based on a Mirage III,the BalzacV discarded the usual 13,700lb/thrust SNECMA Atar G.2 engine in favourof a lighter 4,850lb/thrust Bristol SiddeleyOrpheus.This was augmented by eight2,210lb/thrust RB.108 lift engines, groupedin tandem pairs around the aircraft’s centreof gravity. Hover tests began on October 13,1962 and the first transition to horizontalflight took place on March 18, 1963.

Almost a year later, on January 10,

1964, the aircraft crashed whilst hovering,killing test pilot Jacques Pinier. It was laterdiscovered that Pinier had exceeded thestabilising limits of the aircraft’s three-axisauto-stabilisation system’s ‘puffer pipes’.The BalzacV was rebuilt and flew again onFebruary 2, 1965 but was lost in anotherfatal accident on September 8 that yearwhile being evaluated by the USAF.

Meanwhile, the Mirage IIIV had beenprogressing steadily and the first prototypeperformed its initial hovering trials onFebruary 12, 1965.The aircraft had thesame general layout of earlier Miragefighters but was longer and had a biggerwing. Like the Balzac, it also had nineengines: a single SNECMA-modified Pratt& Whitney JTF10 turbofan (dubbed theTF104) creating 13,900lb/thrust and eightRolls-Royce RB.162-1 lift engines.TheTF104engine was replaced by a 16,750lb/thrust

TF106 before the aircraft made its firsttransition to forward flight in March 1966.

The second prototype had a 18,500lb/thrust TF306 and first flew in June 1966. Iteventually attained Mach 2.04 in level flightbut was never able to take off vertically andfly supersonically in the same sortie. It waslost in an accident on November 28, 1966and this effectively killed the programme.

Although the lift engine concept worked,aircraft fitted with multiple engines sufferedfrom excessive fuel consumption and thenecessity of carrying extra powerplantsresulted in significant amounts of dead weight.

Perhaps the only operational successstory of the lift jet era was the RussianYakovlevYak-38 Forger, which was equippedwith a 15,000lb/thrust Tumansky R-28V-300 turbojet and two smaller 7,870lb/thrust Rybinsk RD-38 engines – the latterhoused in the front portion of the fuselage

The Avrocar was as close to a flying sauceras is possible to imagine. It used the Coandãeffect to provide lift and thrust from a single‘turborotor’ that blew its exhaust gasses out ofthe rim of the disk-shaped aircraft

The Balzac V combined a single BristolSiddeley Orpheus with no fewer thaneight 2,210lb/thrust RB.108 lift engines

The Yak-38 was the SovietNavy’s only operational VTOLstrike fiifighter and served almostexclusively on the Kiev-classaircraft carriers US Navy



and used purely for take-off and landing.The prototype first flew on April 14, 1970and some 231 examples were ultimatelyproduced.As the Soviet Navy’s onlyoperational VTOL strike fighter, theYak-38served almost exclusively on the Kiev-classaircraft carriers. However, with a restrictivethrust to weight ratio, theYak’s usefulpayload was always its Achilles’ heel. Highambient temperatures frequently preventedthe aircraft from carrying any externalstores at all, despite a reduced fuel load.

A much upgradedYak-141 Freestyle – inreality a completely new design bearing starksimilarities to theYak-38 – first flew in March1987 but a Post-Glasnost lack of funds ledto the project being cancelled in 1991.

Flying fansIn the late 1950s and for much of the 1960sa number of American manufacturers

began to explore ‘fan-in-wing’ technologiesas a way of achievingVTOL flight.Thisconfiguration essentially saw lifting fansbeing located in large holes in an otherwiseconventional fixed wing; the fans beingused to provide lift and transition theaircraft to a point where the wing wascapable of keeping the machine aloft.

The earliest – andperhaps most unusual– of these designswas the Avro CanadaVZ-9 Avrocar thatwas created as partof a secret US militaryproject.The Avrocarexploited the Coandã effect to provide liftand thrust from a single ‘turborotor’ thatblew its exhaust gasses out of the rim ofthe disk-shaped aircraft. It was as close toa flying saucer as is possible to imagine.

Designed by John Frost as a fighteraircraft capable of very high speeds andaltitudes, the project was scaled back overtime and eventually abandoned after testsshowed it to have insurmountable thrustand stability problems.The aircraft firstflew on November 12, 1959 but in threeyears of testing never left ground effect.

Far more successfulwas the Ryan XV-5Vertifan: a conventionaldelta-wing jet with alarge fan in each wingand a third, smaller,fan in the nose toprovide balance in

pitch.After its first flight in 1964, one of thetwo prototypes continued to fly until 1971.

Bell’s X-14 of 1957 did not have alifting fan as such, but its two ArmstrongSiddeleyViper engines were equippedwith thrust-deflecting vanes at the aircraft’scentre of gravity to direct the flow ofthe exhaust.The ‘budget’ experimentaljet was mostly constructed from parts ofBeech Bonanzas andT-34 Mentors buthad a top speed of 156kts and a ceilingof 20,000ft – all with an open cockpit!

The X-14’s first transition to horizontalflight took place in May 1958 and a year later,Hawker test pilots Bill Bedford and HughMerewether travelled to the USA to fly theaircraft, prior to making their first flights inthe Hawker P.1127.The X-14 continuedto fly with NASA until 1981, during whichtime it was flown by more than 25 pilotswith no serious incidents or injuries.

Tilting talentEarlyVTOL experiments revealed that itwas possible to tilt the aircraft’s engines toachieve both vertical flight and transitionto forward motion.The earliest drawings ofwhat is now known as a tiltrotor originatedin the 1930s but did not progress towardsa prototype. It would be 1947 before theTranscendental Aircraft Company beganconstructing a working tiltrotor and itwould be 1954 before it actually flew.

However, when the prototype crashed theUSAF withdrew funding in favour of the BellXV-3, which had been designed to explore‘convertiplane’ technologies.The XV-3featured an engine mounted in the fuselagewith drive shafts transferring power torotors mounted on the wingtips that couldtilt 90 degrees from vertical to horizontal.

The XV-3 was first flown on August11, 1955 and although it was limited inperformance, the aircraft flew 110 sortiesand data and experience gleaned was usedto successfully develop the Bell XV-15 –the forerunner of today’s V-22 Osprey.

Bell also explored the requirement for aVTOL troop transport with 300kts capabilityand created the X-22 for the programme.The double-winged aircraft had four tilting

“Avro Canada’s VZ-9Avrocar was as close

to a flying saucer as ispossible to imagine”

Bell’s X-22 was developed tomeet a requirement for a VTOL

troop transport with 300ktscapability.The aircraft had four

tilting ducted fans but the project was cancelledafter the required top speed was never reached

The Ryan XV-5 Vertifan had a large fan ineach wing and a third, smaller fan in thenose to provide balance in pitch


three-bladed ducted fans that enabled eithera vertical take-off or, on a small runway, ashort take-off with the nacelles tilted forwardat approximately 45 degrees. Each fan wasdriven by a General Electric turboshaftengine, one mounted on the end of eachwing. Manoeuvring was achieved by tiltingthe propeller blades in combination with theelevators and ailerons, which were locatedin the thrust stream of the fans.The first oftwo examples flew on March 17, 1966 butthe project was cancelled a year later whenthe required speeds were never reached.

Germany also explored the concept withthe Dornier Do 29 flying for the first timeon December 12, 1958.The aircraft wasbased on the Do 27 light transport, aircraftbut modified with twin Lycoming GO-480engines driving three-bladed pusherpropellers that could be tilted downwardsat an angle of up to 90 degrees to create lift.

Designers discovered that it wasn’t justrotors or propellers that could be tiltedand soon concepts were being dreamedup with jet engines and even entirewings tilting to achieveVTOL handling.

In the USA, Bell combined thefuselage of a Schweizer glider with thewing of a Cessna 170 and the landinggear of a Bell 47 helicopter to createthe Model 65 AirTestVehicle (ATV).

This tiltjet had two 1,000lb/thrust FairchildJ44 turbojet engines – normally used onmissiles and for jet-assisted take-off (JATO)that could be tilted from horizontal to vertical.The aircraft made its first hover on November16, 1954 and proved capable of makingpartial transitions to forward flight but lackedthe thrust to complete the manoeuvre.

Back in Europe, German companiesHeinkel, Messerschmitt and Bölkow joinedforces to create the EWR organisationto develop a much more capabletiltjet – one envisaged as a supersonicreplacement for the F-104 Starfighter.

No doubt taking inspiration from Bell’sstillborn XF-109 fighter, the resultingEWRVJ101C had jet engines mountedin rotating nacelles at the wingtips aswell as four further lift jets within thefuselage to provide hovering lift.

After a series of experiments withtest rigs, EWR proceeded to build twoprototypes, the first of which made the

type’s inaugural hover flight on April 10,1963.Transition to forward flight began onSeptember 20 and the sound barrier wasbroken for the first time on July 29, 1964.

Sadly, theVJ101C was lost in a crashin September 1964 after the autopilotmalfunctioned but the second example flewsoon afterwards and flight-testing continued

until the project was cancelled in 1968.In the early 1960s, when theVJ101C was

still very much under development, theGerman government had commissionedDornier to create aVTOL-capable transportto support its VTOL fighter in the eventof war.The resulting Do 31 was designedaround a pair of Bristol Pegasus vectored-

thrust turbofans in two inboard enginenacelles and eight Rolls-Royce RB.162 liftengines spread between two outer nacelles.

The first prototype was fitted with justthe Pegasus engine and was only capableof conventional flight when it made thetype’s maiden flight on February 10,1967.The second prototype had all ten

engines fitted and began hover testingon November 22 of the same year.

The Do 31 flew well but was heavy andmassively over budget by the time theVJ101C was cancelled. It was thereforeinevitable that the transport aircraftwould also be destined for cancellationin April 1970 – but the Do 31 remainsthe onlyVTOL jet transport ever built.

Canada also explored theVTOL cargolifter concept and its four Canadair CL-84Dynavert aircraft were built using a pairof 1,500shp LycomingT53 turboshaftengines to drive the two 14ft propellers.The aircraft also had a contra-rotatingtail rotor mounted vertically to providefore and aft control during hovering.

The first prototype flew on May 7,1965 but two of the four were ultimatelylost in accidents and no contract for aproduction version was forthcoming.

“Designers dreamed up concepts withjet engines and even entire wings tilting”

Built from spare parts and two Armstrong Siddeley Viper engines, the Ryan X-14 wasan open cockpit VTOL jet!The aircraft served for more than 25 years and was alsoused by British pilots in preparation for early testing with the Hawker P.1127

The Bell XVVXV-3 was designed to explore ‘convertiplane’ technologiesand was the forerunner of today’s V-22 Osprey



In the USA both Hiller Aircraft and theLing-Temco-Vought (LTV) Corporationwere also experimenting with the tiltwingconcept. Hiller’s X-18 was purely a proofof concept aircraft and to speed upconstruction, used turboprops scavengedfrom Lockheed XFV-1 and Convair XFY-1Pogo programmes.The aircraft was besetwith problems and on the 20th flight,in July 1961, a propeller pitch controlproblem at 10,000ft sent the X-18 intoa spin.The crew regained control andlanded, but the X-18 never flew again.

Meanwhile, LTV’s XC-142 was designed asa cargo aircraft from the outset in hope ofwinning military contracts.This boxy aircraftresembled other freighters of the era with ahigh wing and semi-T-tail to enable rear cargoloading but its 67ft span could be rotatedto 100 degrees in order to hover and evenfly backwards. Roll control during the hoverwas provided by differential clutching of thepropellers while power (from four 2,850shpGeneral Electric T64-GE-1 turboprops) wasalso fed to a separate tail rotor, mountedhorizontally to lift the tail whilst hovering.

The XC-142 had a maximum speed ofover 350kts, making it one of the fastestVTOL transport aircraft of the era, but itnever progressed beyond the prototypestage after a tri-services management teamcould not see a requirement for aV/STOLtransport.The sole prototype, which had firstflown on September 29, 1964 was thereforeturned over to NASA for research testingfrom May 1966 until it retired in May 1970.

Present and futureInterestingly, in latter years it has beenthe cargo/freight capabilities ofVTOLdesigns that have seen the most success

with the Bell V-22 Osprey tiltrotor nowin series production for a number of airarms and the Agusta Westland AW609making great steps towards certification.

The next generation of jet fighter for theUSA, UK and countless other nations – theLockheed F-35 Lightning II – is also availablein as aV/STOL variant (the F-35B).This usesa Rolls-Royce LiftSystem that resembles thesystem used on theVJ101C and consistsof a lift fan and a thrust vectoring nozzlewhich allows the main engine exhaust tobe deflected downward at the tail of theaircraft. A lift fan sits near the front of theaircraft and provides counterbalancing thrust.

However, the major area ofVTOLdevelopment in recent years has been inthe Unmanned Aerial Vehicle (UAV) sector,where the ability to operate from ships orconfined areas is a major requirement.

It may be many decades since manfirst achieved vertical flight but the questto perfect it continues to this day. ●

Dornier’s Do 31 was envisaged as a VTOL-capable transport to support the VJ101Cfighter in the event of war. Both projectswere cancelled

The Moller M400 Skycar has been indevelopment for 40 years and promises to bea VTOL flying car capable of transporting fourpeople.The Skycar demonstrated its first hoverin 2003 but no subsequent testing has occurred

The Hiller VZ-1 Pawnee was a unique VTOLaircraft, using contra-rotating ducted fans forlift inside a platform upon which the singlepilot shifted body weight for directional control

The supersonic EWR VJ101C tiltjet was designedas a possible replacement for the F-104Starfighter

The Lunar Landing Research Vehiclewas created by Bell in the early 1960s

as a simulator for the Apollo astronauts.Two were built and used a single jet

engine mounted on a gimbal so that italways pointed vertically to simulate the

behaviour of a lunar lander in the moon’slow-gravity environment. On April 26, 1965

one of the aircraft flew with a Bell 47helicopter acting as a chase aircraft

NASA

The History of VTOL

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