Tail-sitter

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For rocket powered vertical landing vehicles, see VTVL.
The Convair Pogo was one tailsitter design.

A tail-sitter, or tailsitter, is a type of VTOL aircraft that takes off and lands on its tail, then tilts horizontally for forward flight.

Originating in the 1920s with the inventor

Second World War. Development of such aircraft spiked during the late 1940s and 1950s, as aircraft designers and defence planners alike recognised the potential value of fixed-wing aircraft that could perform both a vertical take-off and vertical landing while also transitioning into and out of conventional flight. Inherent problems with tail-sitter aircraft were poor pilot visibility and control difficulties, especially during vertical descent and landing. Programmes to develop manned tail-sitters were typically terminated in the form of the more practical thrust vectoring approach, as used by aircraft such as the Hawker Siddeley Harrier and Yakovlev Yak-38
.

Description

A tail-sitter sits vertically on its tail for takeoff and landing, then tilts the whole aircraft forward for horizontal flight. This is very different from the many other kinds of VTOL technologies, which have horizontally-oriented fuselages.

Tail-sitters change fuselage orientation after take-off. They start off with the back of the aircraft to the ground (...a vertical orientation), and then reorient to a horizontal orientation in flight.

Some tail-sitters then landed conventionally in horizontally-oriented configuration, while others had a much more ambitious goal of landing vertically with the aircraft's back to the ground, a highly hazardous procedure for many reasons, prime of which was increased fuel consumption and limited pilot visibility.

History

Early work

The concept of a tail-sitting aircraft can be attributed to originate with the inventor Nikola Tesla, who filed for an associated patent during 1928.[1] However, no immediate attempt to implement this concept into a functional aircraft would emerge for almost two decades.

During the

Second World War, Nazi Germany worked on the Focke-Wulf Triebflügel (wing-driven) fighter that incorporated the tail-sitter concept into its design. It featured three wings that were mounted radially as a rotor on a rotating section of the fuselage, these were driven by small jet engines positioned on the wingtips to propel the aircraft via this wing rotation. For takeoff and landing, it would fly vertically (akin to a helicopter) before tilting over horizontally to fly as a self-propelled wing generating both lift and thrust. The contemporary Heinkel Lerche project had an annular wing forming a duct around a conventional propeller, and in the transition from vertical to forward flight the lift would have transferred to the wing.[2][3]

Cold War era

During the 1950s, aircraft designers around the world engaged in programmes to develop fixed-wing aircraft that could not only perform both a vertical take-off and vertical landing, but transition into and out of conventional flight as well. As observed by the aviation author Francis K. Mason, a combat aircraft that possessed such qualities would have effectively eliminate the traditional reliance on relatively vulnerable runways by taking off and landing vertically as opposed to the conventional horizontal approach.

postwar era.[5] As the thrust-to-weight ratio of turbojet engines increased sufficiently for a single engine be able to lift an aircraft, designers began to investigate ways of maintaining stability while an aircraft was flying in the VTOL stage of flight.[6]

One company that opted to engage in VTOL research was the

supersonic speeds, suitable for an interceptor aircraft.[5]

SNECMA's design team decided to integrate this radical annual wing design into their VTOL efforts. Accordingly, from this decision emerged the basic configuration of the

Kaman Aircraft to design its own annular-wing vehicle, nicknamed the Flying Barrel.[5]

Accordingly, the United States experimented with its own tail-sitters, typically involving

Washington DC during 1957.[13]

An inherent problem with all these tail-sitter designs was poor pilot visibility, especially of the ground, during vertical descent and landing. Ultimately, most work on applying the concept towards manned aircraft were abandoned upon the arrival of more practical form of VTOL appeared, in the form of thrust vectoring, as used by production aircraft such as the Hawker Siddeley Harrier and Yakovlev Yak-38.[14][15][16] An unmanned aerial vehicle (UAV) does not suffer the problem of pilot attitude. The Dornier Aerodyne is of ducted-fan configuration similar to a coleopter, and a test UAV flew successfully in hover mode in 1972, before development was discontinued.[17] Another contemporary UAV project was the NSRDC BQM-108 that was developed by the United States Navy; although work was discontinued almost immediately after its single successful test flight.[18]

During the 1970s, several studies and wind tunnel models were made of a tail-sitting version of the General Dynamics F-16 Fighting Falcon that was intended for use on board ships; however, it was decided not to pursue further development of the concept due to the large thrust requirement involved, as well as the need for extensive apparatus to handle take-off and landing.[19]

In the present

At present, most of the tail sitter projects or proposals fall under the category of unmanned aircraft such as Bell Apt or Northrop Grumman Tern.

List of tail-sitters

Type Country Date Role Status Description
AeroVironment SkyTote USA 2010 UAV Prototype None
Bachem Ba 349
 Germany 1944 Interceptor Prototype Launched up a vertical tower, landed using parachutes.
Bell Apt USA 2019 UAV Prototype Planned for delivering[20]
Bolköw P 110.1 West Germany 1950s VTOL Fighter Project None [21]
Sukhoi Shkval USSR 1960 Interceptor Development ceased,partial Mockup equipped with a conventional Landing gear.side-by-side afterburner engines.
CDADI VD200 China 2014 UAV Project None
Convair XFY-1 Pogo
 USA 1954 Fighter Prototype None
Dornier Aerodyne Germany 1972 UAV Prototype None
Focke-Wulf Triebflügel Germany 1944 Interceptor Project Rotor wing around middle of fuselage. In-flight transition never resolved.
Focke Wulf Fw 860 West Germany 1950s VTOL Fighter Project None [21]
Heinkel Lerche Germany 1944 Fighter Project None
Heinkel He 231 West Germany 1950s VTOL Fighter Project None
Lockheed Martin Cormorant USA 2008 UAV Prototype None
Lockheed XFV-1
 USA 1954 Fighter Prototype None
Messerschmitt Me X1-21 West Germany 1950s VTOL Fighter Project None [21]
NASA Puffin USA 2010 Private Project None [22]
Northrop Grumman Tern USA 2018 UCAV Prototype None
NSRDC BQM-108 USA 1976 UAV None None
Rotary Rocket Roton ATV USA 1999 Experimental Prototype Rotorcraft test vehicle for proposed SSO space launcher.
Ryan X-13 Vertijet USA 1955 Experimental Prototype Jet powered
SNECMA Coléoptère France 1959 Experimental Prototype Never achieved transition. Had one cylindrical wing.

See also

Look up tailsitter in Wiktionary, the free dictionary.

References

Citations

  1. ^ "Nikola Tesla U.S. Patent 1,655,114 - Apparatus for Aerial Transportation". 1 March 2015. Retrieved 7 July 2016., Tesla Universe.
  2. ^ Sharp, Dan. Luftwaffe: Secret Weapons of the Third Reich. Mortons, 2015. pp. 98-101.
  3. ISBN 9781909160569
    .
  4. ^ Mason 1967, p. 3.
  5. ^ a b c d e Davis, Jeremy (July 2012). "Cancelled: Vertical Flyer". Air & Space Magazine.
  6. ^ a b Gaillard 1990, p. 200.
  7. ^ Gaillard 1990, p. 180.
  8. ^ Haimes, Brian J. (15 November 2006). "The Coleopter - a revolutionary experimental aircraft". New Scientist.
  9. ^ Taylor 1977, p. 63.
  10. ^ "Convair XFY." Flight, 12 November 1954, p. 696.
  11. ^ Winchester 2005, p. 135.
  12. ^ Allen 2007, p. 20.
  13. ^ Darling, Jeff (13 June 2011). "Ryan X-13 Vertijet". Diseno. Archived from the original on 28 January 2014. Retrieved 9 February 2014.
  14. ^ Wilson 2000, p. 145.
  15. ^ "Yak-36 Forger—interim V/Stol." Flight International, 2 May 1981.
  16. ^ Brown 1970, p. 81.
  17. ^ "Eine Dokumentation zur Geschichte des Hauses Dornier." Dornier GmbH, 1983. p. 214.
  18. ^ Eilertson 1977.
  19. National Aeronautics and Space Administration
    . Retrieved October 16, 2016.
  20. ^ "Bell APT". Bell Flight. Retrieved 14 October 2019.
  21. ^ a b c Hirschberg, Mike (1 November 2000). "V/STOL Fighter Programs in Germany: 1956-1975" (PDF). robertcmason.com.
  22. ^ Choi, Charles Q. (19 January 2010). "Electric Icarus: NASA Designs a One-Man Stealth Plane". Scientific American. Retrieved 27 February 2010.

Bibliography

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