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VTOL

From Wikipedia, the free encyclopedia
"Heli-Jet" redirects here. For the helicopter airline based in Vancouver, British Columbia, Canada, seeHelijet.
For rocket vertical takeoff and landing, seeVTVL.

Avertical take-off and landing(VTOL)aircraftis one that cantake off and landvertically without relying on arunway.This classification can include a variety of types ofaircraftincludinghelicoptersas well asthrust-vectoringfixed-wing aircraftand other hybrid aircraft with poweredrotorssuch ascyclogyros/cyclocoptersandgyrodynes.[1]

AnRAFF-35B Lightning IIdemonstrating a vertical landing

Some VTOL aircraft can operate in other modes as well, such asCTOL(conventional take-off & landing),STOL(short take-off & landing), orSTOVL(short take-off & vertical landing). Others, such as some helicopters, can only operate as VTOL, due to the aircraft lackinglanding gearthat can handletaxiing.VTOL is a subset ofV/STOL(vertical or short take-off & landing).

Somelighter-than-air aircraftalso qualify as VTOL aircraft, as they can hover, takeoff and land with vertical approach/departure profiles.[2]

Electric vertical takeoff and landing aircraft, oreVTOLs,are being developed along with more autonomous flight control technologies and mobility-as-a-service (MaaS) to enable advanced air mobility (AAM), that could include on-demand air taxi services, regional air mobility, freight delivery, andpersonal air vehicles(PAVs).[3]

Besides the ubiquitous helicopters, there are currently two types of VTOL aircraft in military service:tiltrotoraircraft, such as theBell Boeing V-22 Osprey,and thrust-vectoring airplanes, such as theHarrier familyand newF-35B Lightning IIJoint Strike Fighter(JSF). In the civilian sector currently only helicopters are in general use (some other types of commercial VTOL aircraft have been proposed and are under development as of 2017). Generally speaking, VTOL aircraft capable of STOVL use it wherever possible, since it typically significantly increases takeoff weight, range or payload compared to pure VTOL.[4]

History

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Props, proprotors and advanced rotorcraft

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See also:Helicopter § History,andTiltrotor § History

The idea of vertical flight has been around for thousands of years, and sketches for a VTOL (helicopter) show up inLeonardo da Vinci's sketch book. Manned VTOL aircraft, in the form of primitive helicopters, first flew in 1907, but would take until after World War Two to be perfected.[5][6]

In addition tohelicopterdevelopment, many approaches have been tried to develop practical aircraft with vertical take-off and landing capabilities, includingHenry Berliner's 1922–1925 experimental horizontal rotor fixed wing aircraft, andNikola Tesla's 1928 patent, and George Lehberger's 1930 patent for relatively impractical VTOL fixed wing airplanes with a tilting engines.[7][8][9]In the late 1930s British aircraft designerLeslie Everett Bayneswas issued a patent for theBaynes Heliplane,another tilt rotor aircraft. In 1941 German designerHeinrich Focke's began work on theFocke-Achgelis Fa 269,which had two rotors that tilted downward for vertical takeoff, but wartime bombing halted development.[9]

Convair XFY-1 Pogoin flight

In May 1951, bothLockheedandConvairwere awarded contracts in the attempt to design, construct, and test two experimental VTOL fighters. Lockheed produced theXFV,and Convair producing theConvair XFY Pogo.Both experimental programs proceeded to flight status and completed test flights 1954–1955, when the contracts were cancelled.[10]Similarly, theRyan X-13 Vertijetflew a series of test flights between 1955 and 1957, but also suffered the same fate.[11]

The use of vertical fans driven by engines was investigated in the 1950s. The US built an aircraft where thejet exhaust drove the fans,while British projects not built included fans driven by mechanical drives from the jet engines.[citation needed]

Bell XV-15

NASAhas flown other VTOL craft such as theBell XV-15research craft (1977), as have theSoviet NavyandLuftwaffe.Sikorskytested an aircraft dubbed theX-Wing,which took off in the manner of a helicopter. The rotors would become stationary in mid-flight, and function as wings, providing lift in addition to the static wings.Boeing X-50is aCanard Rotor/Wingprototype that utilizes a similar concept.[12]

Fairey Jet Gyrodyne

A different British VTOL project was thegyrodyne,where a rotor is powered during take-off and landing but which then freewheels during flight, with separate propulsion engines providing forward thrust. Starting with theFairey Gyrodyne,this type of aircraft later evolved into the much larger twin-enginedFairey Rotodyne,that usedtipjetsto power the rotor on take-off and landing but which then used twoNapier Elandturbopropsdriving conventional propellers mounted on substantial wings to provide propulsion, the wings serving to unload the rotor during horizontal flight. The Rotodyne was developed to combine the efficiency of a fixed-wing aircraft at cruise with the VTOL capability of a helicopter to provide short haul airliner service from city centres to airports.

U.S. Marines jump from aBell-Boeing V-22 Osprey,the first productiontiltrotoraircraft
Canadair CL-84 DynavertCL-84-1 (CX8402) on display at theCanada Aviation and Space Museumin Ottawa, Ontario

TheCL-84 Dynavertwas a CanadianV/STOLturbine tilt-wing monoplane designed and manufactured byCanadairbetween 1964 and 1972. The Canadian government ordered three updated CL-84s for military evaluation in 1968, designated the CL-84-1. From 1972 to 1974, this version was demonstrated and evaluated in the United States aboard the aircraft carriers USSGuamand USSGuadalcanal,and at various other centres.[13]These trials involved military pilots from the United States, the United Kingdom and Canada. During testing, two of the CL-84s crashed due to mechanical failures, but no loss of life occurred as a result of these accidents. No production contracts resulted.[14]

Although tiltrotors such as theFocke-Achgelis Fa 269of the mid-1940s and the Centro Técnico Aeroespacial "Convertiplano" of the 1950s reached testing or mock-up stages, theBell-Boeing V-22 Ospreyis considered the world's first productiontiltrotoraircraft. It has one three-bladedproprotor,turbopropengine, and transmissionnacellemounted on each wingtip. The Osprey is a multi-mission aircraft with both a vertical takeoff and landing (VTOL) and short takeoff and landing capability (STOL). It is designed to perform missions like a conventionalhelicopterwith the long-range, high-speed cruise performance of aturbopropaircraft. The FAA classifies the Osprey as a model ofpowered liftaircraft.[15]

Attempts were made in the 1960s to develop a commercial passenger aircraft with VTOL capability. TheHawker SiddeleyInter-City Vertical-Lift proposal had two rows of lifting fans on either side. However, none of these aircraft made it to production after they were dismissed as too heavy and expensive to operate.[16][unreliable source?][17]

In 2018 Opener Aero demonstrated an electrically powered fixed-wing VTOL aircraft, theBlackfly,which the manufacturer claims is the world's first ultralight fixed-wing, all-electric, vertical take-off and landing aircraft.[18]

Modern drones

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ASchiebel Camcopter S-100,a modern VTOLunmanned aerial vehicle

In the 21st century, unmanned drones are becoming increasingly commonplace. Many of these have VTOL capability, especially thequadcoptertype.[19]

Jet lift

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The Ryan X-13

Tail-sitters

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In 1947,Ryan X-13 Vertijet,atailsitterdesign, was ordered by the US Navy, who then further issued a proposal in 1948 for an aircraft capable of vertical takeoff and landing (VTOL) aboard platforms mounted on the afterdecks of conventional ships. BothConvairandLockheedcompeted for the contract but in 1950, the requirement was revised, with a call for a research aircraft capable of eventually evolving into a VTOL ship-based convoy escort fighter.

At the end of 1958, the FrenchSNECMA Coléoptère,a tailsitterannular wingdesign, performed its maiden flight. However the sole prototype was destroyed on its ninth flight in 1959, and financing was never sourced for a second prototype.

Conventional design

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"Flying Bedstead" - Rolls-Royce Thrust Measuring Rig

Another more influential early functional contribution to VTOL wasRolls-Royce'sThrust Measuring Rig( "flying bedstead" ) of 1953. This led to the first VTOL engines as used in the first British VTOL aircraft, theShort SC.1(1957), Short Brothers and Harland, Belfast which used four vertical lift engines with a horizontal one for forward thrust.

The Short SC.1 a VTOL delta aircraft

TheShort SC.1was the first British fixed-wing VTOL aircraft. The SC.1 was designed to study the problems with VTOL flight and the transition to and from forward flight. The SC.1 was designed to meet a Ministry of Supply (MoS) request for tender (ER.143T) for a vertical take-off research aircraft issued in September 1953. The design was accepted by the ministry and a contract was placed for two aircraft (XG900 and XG905) to meet Specification ER.143D dated 15 October 1954. The SC.1 was also equipped with the first "fly-by-wire" control system for a VTOL aircraft. This permitted three modes of control of the aerodynamic surfaces or the nozzle controls.

TheRepublic AviationAP-100was a prototype VTOL 6xGeneral Electric J85Turbojet engined nuclear capable strike fighter concept designed byAlexander Kartvelithat had 3x ducted fans in the centre of its fuselage and tail as a possible contender for theTFX Program.[20][21][22]Another design was the A400 AVS that used variable geometry wings but was found too complicated, however it led to the development of theAFVGwhich in turn helped the development of thePanavia Tornado.

TheSoviet Union's VTOL aircraft, theYakovlev Yak-38

TheYakovlev Yak-38was aSoviet NavyVTOL aircraft intended for use aboard their light carriers, cargoships, and capital ships. It was developed from theYakovlev Yak-36experimental aircraft in the 1970s. Before the Soviet Union broke up, a supersonic VTOL aircraft was developed as the Yak-38's successor, theYak-141,which never went into production.[23]

A German V/STOLVJ101on display at theDeutsches Museum,Munich, Germany
Do 31 E3on display at theDeutsches Museum,Germany

In the 1960s and early 1970s, Germany planned three different VTOL aircraft. One used theLockheed F-104 Starfighteras a basis for research for aV/STOLaircraft. Although two models (X1 and X2) were built, the project was canceled due to high costs and political problems as well as changed needs in theGerman Air Forceand NATO. TheEWR VJ 101C did perform free VTOL take-offs and landings, as well as test flights beyond mach 1 in the mid- and late 60s. One of the test-aircraft is preserved in theDeutsches Museumin Munich, Germany, another outside Friedrichshafen Airport. The others were the VFW-FokkerVAK 191Blight fighter and reconnaissance aircraft, and theDornier Do 31E-3 (troop) transport.[24]

TheLLRVwas aspacecraftsimulator for the Apollo lunar lander.[25]It was designed to mimic the flight characteristics of thelunar module(LEM), which had to rely on a reaction engine to land on the Moon.

The idea of using the same engine for vertical and horizontal flight by altering the path of the thrust was conceived byMichel Wibault.[26]It led to theBristol Siddeley Pegasusengine which used four rotatingnozzlesto direct thrust over a range of angles.[27]This was developed side by side with an airframe, theHawker P.1127,which became subsequently the Kestrel and then entered production as theHawker Siddeley Harrier,though the supersonicHawker Siddeley P.1154was canceled in 1965. The French in competition with the P.1154 had developed a version of theDassault Mirage IIIcapable of attainingMach1. TheDassault Mirage IIIVachieved transition from vertical to horizontal flight in March 1966, reaching Mach 1.3 in level flight a short time later.

V/STOL

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Landing ofHarrier jump jetwithIndian Naval Air Arm

The Harrier is usually flown inSTOVLmode, which enables it to carry a higher fuel or weapon load over a given distance.[4]In V/STOL the VTOL aircraft moves horizontally along the runway before taking off using vertical thrust. This gives aerodynamic lift as well as thrust lift and permits taking off with heavier loads and is more efficient. When landing the aircraft is much lighter due to the loss of propellant weight and a controlled vertical landing is possible. An important aspect of Harrier STOL operations aboard naval carriers is the "ski jump" raised forward deck, which gives the craft additional vertical momentum at takeoff.[28]

The March 1981 cover ofPopular Scienceshowed three illustrations for its "Tilt-engine V/STOL - speeds like a plane, lands like a copter" front-page feature story.;[29]a followup story was part of the April 2006 issue that mentioned "the fuel-consumption and stability problems that plagued earlier plane/copter."[30]

Retired from the BritishRoyal Navyin 2006,[31]theIndian Navycontinued to operateSea Harriersuntil 2016,[32]mainly from itsaircraft carrierINSViraat.The latest version of the Harrier, theBAE Harrier II,was retired in December 2010 after being operated by the BritishRoyal Air Forceand Royal Navy. TheUnited States Marine Corpsand the Italian and Spanish navies all continue to use theAV-8B Harrier II,an American-British variant. Replacing the Harrier II/AV-8B in the air arms of the US and UK is the STOVL variant of theLockheed Martin F-35 Lightning II,the F-35B.[33]

Rockets

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Main article:VTVL

SpaceXdevelopedseveral prototypes of Falcon 9to validate various low-altitude, low-velocity engineering aspects of itsreusable launch system development program.[34]The first prototype, Grasshopper, made eight successful test[35]flights in 2012–2013. It made its eighth, and final, test flight on October 7, 2013, flying to an altitude of 744 metres (2,441 ft) before making its eighth successful VTVL landing.[36][37]This was the last scheduled test for the Grasshopper rig; next up will be low altitude tests of the Falcon 9 Reusable (F9R) development vehicle in Texas followed by high altitude testing in New Mexico.

On November 23, 2015,Blue Origin's New Shepard booster rocket made the first successful vertical landing following an uncrewed suborbital test flight that reached space.[38]On December 21, 2015,SpaceXFalcon 9first stage made a successful landing after boosting 11 commercial satellites tolow Earth orbitonFalcon 9 Flight 20.[39]These demonstrations opened the way for substantial reductions in space flight costs.[40]

Rotorcraft

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Helicopter

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Main article:Helicopter

The helicopter's form of VTOL allows it to take off and land vertically, to hover, and to fly forwards, backwards, and laterally. These attributes allow helicopters to be used in congested or isolated areas wherefixed-wing aircraftwould usually not be able to take off or land. The capability to efficiently hover for extended periods of time is due to the helicopter's relatively long, and hence efficient rotor blades, and allows a helicopter to accomplish tasks that fixed-wing aircraft and other forms of vertical takeoff and landing aircraft could not performat least as well until 2011.

On the other hand, the long rotor blades restrict the maximum speed to about 250 miles per hour (400 km/h) of at least conventional helicopters, asretreating blade stallcauses lateral instability.

Autogyro

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Main article:Autogyro

Autogyros are also known as gyroplanes or gyrocopters. The rotor is unpowered and rotates freely in the airflow as the craft travels forward, so the craft needs a conventional powerplant to provide thrust. An autogyro is not intrinsically capable of VTOL: for VTO the rotor must be spun up to speed by an auxiliary drive, and vertical landing requires precise control of rotor momentum and pitch.

Gyrodyne

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Main article:Gyrodyne

Gyrodynes are also known as compound helicopters or compound gyroplanes. A gyrodyne has the powered rotor of a helicopter with a separate forward thrust system of an autogyro. Apart from take-off and landing the rotor may be unpowered and autorotate. Designs may also include stub wings for added lift.

Cyclogyro

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Main article:Cyclogyro

A cyclogyro or cyclocopter has a rotary wing whose axis and surfaces remain sideways across the airflow, as with a conventional wing.

Powered lift

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Main article:Powered lift

There are number of designs for achieving power lift, and some designs may use more than one. There are many experimental designs that have unique design features to achieve powered lift.

The F-35B uses a ducted fan and also directs (vectors) its rear exhaust downward.

Convertiplane

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Main article:Convertiplane

A convertiplane takes off under rotor lift like a helicopter, then transitions to fixed-wing lift in forward flight. Examples of this include theBell Boeing V-22 Osprey

Tiltrotor

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Main article:Tiltrotor

A tiltrotor or proprotor tilts its propellers or rotors vertically for VTOL and then tilts them forwards for horizontal wing-borne flight, while the main wing remains fixed in place.

Tilting ducted fan

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Similar to tiltrotor concept, but withducted fans.As it can be seen in theBell X-22.

Tiltwing

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Main article:Tiltwing

A tiltwing has its propellers or rotors fixed to a conventional wing and tilts the whole assembly to transition between vertical and horizontal flight.

Tail-sitter

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Main article:Tail-sitter

A tail-sitter sits vertically on its tail for takeoff and landing, then tilts the whole aircraft forward for horizontal flight.

Vectored thrust

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Main article:Thrust vectoring

Thrust vectoring is a technique used for jet and rocket engines, where the direction of the engine exhaust is varied. In VTOL, the exhaust can be varied between vertical and horizontal thrust.

Tiltjet

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Main article:Tiltjet

Similar to tiltrotor concept, but with turbojet or turbofan engines instead of ones with propellers.

Lift jets

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Main article:Lift jet

A lift jet is an auxiliary jet engine used to provide lift for VTOL operation, but may be shut down for normal wing-borne flight. TheYak-38is the only production aircraft to employ lift jets.

Lift fans

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Main article:Lift fan

Lift fan is an aircraft configuration in which lifting fans are located in large holes in an otherwise conventional fixed wing or fuselage. It is used for V/STOL operation.

The aircraft takes off using the fans to provide lift, then transitions to fixed-wing lift in forward flight. Several experimental craft have been flown, but only theF-35 Lightning IIentered into production.

Lift via Coandă effect

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Main article:Coandă effect

Aircraft in which VTOL is achieved by exploiting theCoandă effectare capable of redirecting air much likethrust vectoring,but rather than routing airflow through a duct, the airflow is simply routed along an existing surface, which is usually the body of the craft allowing less material and weight.

TheAvro Canada VZ-9 Avrocar,or simply the VZ-9, was a Canadian VTOL aircraft developed byAvro Aircraft Ltd.which utilizes this phenomenon by blowing air into a central area, then it is directed down over the top surface, which isparabolicand resembles a bowedflying saucer.Due to the Coandă effect, the airflow is attracted to the nearest surface and continues to move along that surface despite the change in the surface's direction away from the airflow. The craft is designed to direct the airflow downward to provide lift.

Jetoptera announced a proposed line of aircraft based on what it called fluidic propulsion that employs the Coandă effect. The company claims anOswald efficiency numberof 1.45 for its boxwing design. Other claims include increased efficiency, 30% lower weight, reduced complexity, as much as 25dBAlower (and atonal) noise, shorter wings, and scalability.[41][42]Jetoptera says its approach yields thrust augmentation ratios exceeding 2.0 and 50% fuel savings when compared to aturbofanin static or hovering conditions. Its efflux can be used for Upper Surface Blown architectures to boost theLift Coefficientto values exceeding 8.0.

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  • X-35B Demonstrator flight, transition to STOVL configuration, vertical take off, inflight re-fueling, vertical hover and landing
  • X-35B Demonstrator vertical landing

See also

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References

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Notes

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  1. ^Laskowitz, I. B. (1961)."Vertical Take-Off and Landing (Vtol) Rotorless Aircraft with Inherent Stability".Annals of the New York Academy of Sciences.93(1): 3–24.Bibcode:1961NYASA..93....3L.doi:10.1111/j.1749-6632.1961.tb30485.x.ISSN0077-8923.S2CID84160729.
  2. ^BILL VIRGIN (December 2017)."Plimp, a Plane-Blimp Hybrid, Is Looking to Disrupt the Drone Market - Seattle brothers James and Joel Egan are adding a new airship to the drone market, and it could be available as soon as next year".Seattle Business Magazine.Retrieved16 November2021.
  3. ^Le Bris, G. et al. (2022). "ACRP Research Report 236: Preparing Your Airport for Electric Aircraft and Hydrogen Technologies". Transportation Research Board, Washington, DC:https://nap.nationalacademies.org/catalog/26512/preparing-your-airport-for-electric-aircraft-and-hydrogen-technologies
  4. ^abKhurana KC (2009).Aviation Management: Global Perspectives.Global India Publications. p. 133.ISBN9789380228396.
  5. ^Yefim Gordon, The History of VTOL, page 28
  6. ^John Whiteclay Chambers, The Oxford Companion to American Military History, Oxford University Press, USA, 1999, page 748
  7. ^us 1655113
  8. ^Rayl, A. J. S."Nikola Tesla's Curious Contrivance".Air & Space Magazine.Retrieved2021-04-29.
  9. ^ab"Tiltrotor".globalsecurity.org.Retrieved2019-10-20.
  10. ^Allen 2007, pp. 13–20.
  11. ^"The new Vertijet's straight-up flight: X-13 takes off like a rocket, lands tailfirst".Life.Time Inc. 1957-05-20. p. 136.
  12. ^Simonsen, Erik."Another one for the X files: The Boeing Canard Rotor/Wing demonstrator officially becomes X-50A".boeing.Retrieved2021-04-29.
  13. ^Khurana, K. C. (2009).Aviation Management: Global Perspectives.Global India Publications. p. 134.ISBN978-93-80228-39-6.
  14. ^Boniface 2000, p. 74.
  15. ^Norton 2004, pp. 6–9, 95–96.
  16. ^"BAE animates mothballed Intercity Vertical-Lift Aircraft".aerospace-technology.Retrieved2021-04-29.
  17. ^"Forgotten 1960s 'Thunderbirds' projects brought to life".BAE Systems | International.Retrieved2021-04-29.
  18. ^O'Connor, Kate (12 July 2018)."Opener Reveals Ultralight eVTOL".AVweb.Archived fromthe originalon 27 January 2023.Retrieved13 July2018.
  19. ^Woodbridge, Ewan; Connor, Dean T.; Verbelen, Yannick; Hine, Duncan; Richardson, Tom; Scott, Thomas B. (2023-06-28)."Airborne gamma-ray mapping using fixed-wing vertical take-off and landing (VTOL) uncrewed aerial vehicles".Frontiers in Robotics and AI.10.doi:10.3389/frobt.2023.1137763.ISSN2296-9144.PMC10337992.PMID37448876.
  20. ^Project Hummingbird (Technical Report) A Technical Summary and Compilation of Characteristics and Specifications on Steep-Gradient Aircraft, Volume 88, April 1961. By United States Federal Aviation Agency. Page 143–144, Figure 175.
  21. ^Air Progress History of Aviation Spring 1961 edition
  22. ^Aviation Week and Space Technology, Lift-Fan Tests Show VTOL Potential. August 8, 1960
  23. ^"Vertical take-off/landing aircraft: Yak-38".yak.ru.Yakovlev Design Bureau.16 July 2008.Retrieved2021-04-29.
  24. ^Jackson 1976, p. 143.
  25. ^"NASA - NASA Dryden Technology Facts - Lunar Landing Research Vehicle".nasa.gov.Archived fromthe originalon 2018-12-23.Retrieved2021-04-29.
  26. ^Dow, Andrew (2009).Pegasus: The Heart of the Harrier.Barnsley, South Yorkshire, UK: Pen & Sword Aviation. pp. 29–46.ISBN978-1-84884-042-3.Retrieved13 June2020.
  27. ^"Airfoil"(PDF).Basics of Aeronautics.Retrieved24 May2015.
  28. ^"The genius of the naval jump-jet".The Maritime Foundation. 31 October 2019.Retrieved20 January2020.
  29. ^"Tilt-engine V/STOL - speeds like a plane, lands like a copter".Popular Science.March 1981. p. 3.
  30. ^"V/STOL".Popular Science.April 2006. p. 118.
  31. ^"Hover and out: UK Royal Navy retires the Sea Harrier".FlightGlobal.28 March 2006.Retrieved20 January2020.
  32. ^Raghuvanshi, Vivek (21 March 2016)."Indian Navy Retires Sea Harriers".Defense News.Retrieved20 January2020.
  33. ^Roblin, Sebastien (13 October 2018)."The Royal Navy Is Back (Thanks to the F-35 and Two New Aircraft Carriers)".National Interest.Retrieved20 January2020.
  34. ^ "Reusable rocket prototype almost ready for first liftoff".Spaceflight Now.2012-07-09.Retrieved2012-07-13.SpaceX has constructed a half-acre concrete launch facility in McGregor, and the Grasshopper rocket is already standing on the pad, outfitted with four insect-like silver landing legs.
  35. ^"Grasshopper Completes Highest Leap to Date".SpaceX. 10 March 2013. Archived fromthe originalon 29 April 2013.Retrieved11 March2013.
  36. ^"Grasshopper flies to its highest height to date".Social media information release.SpaceX. 12 October 2013.Retrieved14 October2013.WATCH: Grasshopper flies to its highest height to date – 744 m (2441 ft) into the Texas sky.
  37. ^Grasshopper 744m Test | Single Camera (Hexacopter),retrieved2021-04-29
  38. ^"Blue Origin make historic rocket landing".Blue Origin. November 24, 2015.RetrievedNovember 24,2015.
  39. ^"SpaceX Twitter post".Twitter.Retrieved2021-04-29.
  40. ^Puiu, Tibi (2013-08-20)."SpaceX reusable rocket will cut space launch prices 100 fold".ZME Science.Retrieved2021-04-29.
  41. ^Jetoptera's Bladeless Propulsion System,Electric Aviation, February 18, 2021,archivedfrom the original on 2021-11-17,retrieved2021-04-29
  42. ^Blain, Loz (2021-04-28)."Jetoptera VTOL aircraft design features" bladeless fans on steroids "".New Atlas.Archivedfrom the original on 2021-04-30.Retrieved2021-04-30.

Bibliography

[edit]
  • Allen, Francis J. "Bolt upright: Convair's and Lockheed's VTOL fighters".Air Enthusiast(Key Publishing), Volume 127, January/February 2007.ISSN0143-5450.
  • Boniface, Patrick. "Tilt-wing Testing".Aeroplane,Vol. 28, no. 3, March 2000, pp. 72–78.
  • Campbell, John P.Vertical Takeoff & Landing Aircraft.New York: The MacMillan Company, 1962.
  • Harding, Stephen. "Flying Jeeps: The US Army's Search for the Ultimate 'Vehicle'".Air Enthusiast,No. 73, January/February 1998, pp. 10–12. Stamford, Lincs, UK: Key Publishing.ISSN0143-5450.
  • Jackson, Paul A.German Military Aviation 1956–1976.Hinckley, Leicestershire, UK: Midland Counties Publications, 1976.ISBN0-904597-03-2.
  • Khurana, K. C.Aviation Management: Global Perspectives.Singapore: Global India Publications, 2009.ISBN978-9-3802-2839-6.
  • Markman, Steve and Bill Holder.Straight Up: A History of Vertical Flight.Atglen, Pennsylvania: Schiffer Publishing, 2000.ISBN0-7643-1204-9.
  • Norton, Bill.Bell Boeing V-22 Osprey, Tiltrotor Tactical Transport.Earl Shilton, Leicester, UK: Midland Publishing, 2004.ISBN1-85780-165-2.
  • Rogers, Mike.VTOL: Military Research Aircraft.New York: Orion Books, 1989.ISBN0-517-57684-8.
  • Büchi, Roland.Fascination Quadrocopter.Norderstedt, BoD, English Version, 2011.ISBN978-3-8423-6731-9
[edit]
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