Fastest propeller-driven aircraft
A number of aircraft have claimed to be the fastest propeller-driven aircraft. This article presents the current record holders for several sub-classes of propeller-driven aircraft that hold recognized, documented speed records. Fédération Aéronautique Internationale (FAI) records are the basis for this article.[1] Other contenders and their claims are discussed, but only those made under controlled conditions and measured by outside observers. Pilots during World War II sometimes claimed to have reached supersonic speeds in propeller-driven fighters during emergency dives[citation needed], but these speeds are not included as accepted records.
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[edit] Propeller versus jet propulsion
Aircraft that use propellers as their prime propulsion device constitute a historically important subset of aircraft, despite inherent limitations to their speed. Aircraft powered by piston engines get virtually all of their thrust from the propeller driven by the engine (a few piston engined aircraft derive some thrust from the engine's exhaust gases). All aircraft prior to World War II (except for a tiny number of early jet aircraft and rocket airplanes) used piston engines to drive propellers, so all Flight airspeed records prior to 1944 were necessarily set by propeller-driven aircraft. Rapid advances in jet engine technology during World War II meant that no propeller-driven aircraft would ever again hold an absolute air speed record. Shock wave formation in propeller-driven aircraft at speeds near sonic conditions, impose limits not encountered in jet aircraft.
Jet engines, particularly turbojets, are a type of gas turbine configured such that most of the work available results from the thrust of the hot exhaust gases. High bypass turbofans that are used in all modern commercial jetliners, and most modern military aircraft, get most of their thrust from the internal fan, which is powered by a gas turbine; turboprop engines are similar, but use an external propeller rather than an internal fan. The hot exhaust gas from a turboprop engine can give a small amount of thrust, but the propeller is the main source of thrust.
[edit] Turboprops
The Tupolev Tu-114, a large aircraft with four turboprop engines, has a maximum speed of 870 km/h (540 mph, Mach 0.73).[2] The 11,000 kW (15,000 hp) Kuznetsov NK-12 turboprop engines designed for the Tupolev Tu-95 (and used to power the derivative Tu-114) are the most powerful turboprops ever built and drive large contra-rotating propellers. This engine-propeller combination gives the Tu-114 the official distinction of being the fastest propeller-driven plane in the world, a record it has held since 1960.[1][3]
Probably the fastest aircraft ever fitted with an operating propeller was the experimental McDonnell XF-88B, which was made by installing an Allison T38 turboshaft engine in the nose of a pure jet-powered XF-88 Voodoo. This unusual aircraft was intended to explore the use of high-speed propellers and achieved supersonic speeds.[4] This aircraft is not considered to be propeller-driven since most of the thrust was provided by two jet engines.
An oft-cited contender for the fastest propeller-driven aircraft is the XF-84H Thunderscreech. This aircraft is named in Guinness World Records, 1997, as the fastest in this category with a speed of 1,002 km/h (623 mph, Mach 0.83).[5] While it may have been designed as the fastest propeller-driven aircraft, this goal was not realized due to its inherent instability.[6] This record speed is also inconsistent with data from the National Museum of the United States Air Force, which gives a top speed of 837 km/h (520 mph, Mach 0.70),[7] slower than the Tu-114.
[edit] Piston engines
The more "traditional" class of propeller-driven aircraft are those powered by piston engines, which includes nearly all aircraft from the Wright brothers up through World War II. Today, piston engines are used almost exclusively on light, general aviation aircraft. The record for the fastest single-engined piston plane is held by a modified Grumman F8F Bearcat, the Rare Bear, with a speed of 850.24 km/h (528.31 mph) on 21 August 1989 at Las Vegas, New Mexico, United States of America.[8][9]
The FAI record for the fastest piston-powered aircraft, over a long distance (1,000 km (620 mi)) is 660.53 km/h (410.43 mph) set on 20 June 1946 by a Boeing B-29 Superfortress of the United States Army Air Forces.[10] Higher speed records may exist for other aircraft but are unofficial and not measured by FAI.
[edit] Other claimants
The first propeller-driven aircraft to set a speed record was the 1903 Wright Flyer which managed a pedestrian 48 km/h (30 mph) during its first flight. The Bleriot XI reached 75 km/h (47 mph) in 1909. The limits of technology during the early years of flight led to a threshold of approximately 320 km/h (200 mph) for the fabric-covered biplanes of the World War I era and shortly after. In 1925, US Army Lt. Cyrus K. Bettis flying a Curtiss R3C won the Pulitzer Trophy Race with a speed of 400.6 km/h (248.9 mph).[11]
As aircraft designers adopted all-metal monoplanes in the 1930s, speeds jumped into the 700 km/h (430 mph) range with the Macchi M.C.72 reaching a top speed of 709 km/h (441 mph), which still stands as the record for piston-powered seaplanes.[12] The Messerschmitt Me 209 V1 set a new world speed record of almost 756 km/h (470 mph) on 26 April 1939, and the Republic XP-47J (a variant of the P-47 Thunderbolt) reached 813 km/h (505 mph) in testing, while the Supermarine Spiteful unofficially reached 494 mph (795 km/h). The record-shattering flight, on 2 October 1941, of one of the Messerschmitt Me 163 rocket fighter prototypes that reached a top speed of 624 mph (1,004 km/h), as well as development of jet-powered fighters by both the Allies and Axis powers during World War II, ensured that all new absolute air speed records would be held by jet or rocket-powered aircraft.
During the 1950s, two unorthodox United States Navy fighter prototypes married turboprop engines with a "tailsitting design", the Convair XFY "Pogo" and the Lockheed XFV "Salmon". Maximum design speeds of 980 km/h (610 mph) at 4,600 m (15,100 ft) and 930 km/h (580 mph) respectively have been quoted. However, the Lockheed XFV was fitted with a less powerful engine than it was designed for and had makeshift un-retractable landing gear for horizontal takeoff and landing[13] and the Convair XFY had a makeshift landing gear to support it in a vertical position and it was usually flown with the cockpit open in case the pilot needed to escape, since the ejection seat was thought to be unreliable.[14] These aircraft had "compromised in-flight speed" because of the conflicting demands of vertical and horizontal flight.[15]
[edit] See also
[edit] References
- Notes
- ^ a b "FAI official database" Fédération Aéronautique Internationale. Retrieved: 5 September 2007.
- ^ "Tu_114 data." Aerospaceweb. Retrieved: 5 September 2007.
- ^ "Aircraft Speed Records." Aerospaceweb. Retrieved: 5 September 2007.
- ^ "NASA History pages." NASA. Retrieved: 4 September 2007.
- ^ Young 1997, p. 137.
- ^ Hendrix 1977, p. 408. Quote: The XF-84H never achieved its designer's dreams of being the first propeller-driven aircraft to attain supersonic flight. In fact, it never flew over 450 kt indicated, since at that speed, it developed an unhappy practice of 'snaking', apparently losing longitudinal stability. NOTE: 450 kt=518 mph
- ^ "XF-84H Fact sheet." USAF. Retrieved: 3 April 2009.
- ^ "'Rare Bear' web site." Rare Bear Air Race Team, 2008. Retrieved: 13 November 2007.
- ^ www.AeroSpaceWeb.org "Aircraft speed records." Aerospaceweb. Retrieved: 13 November 2007.
- ^ "Official FAI database." Boeing. Retrieved: 5 September 2007.
- ^ Taylor and Munson 1973, p. 243.
- ^ Taylor and Munson 1973, p. 245.
- ^ "Lockheed FXV data." globalsecurity. Retrieved: 24 February 2009.
- ^ "Data for Convair XFY." National Air and Space Museum. Retrieved: 24 February 2009.
- ^ Hite, Kennith F., Lieutenant Colonel. "Why the VTOL Fighter?" Air University Review, US Air Force Air University, July–August 1968. Retrieved: 15 January 2011.
- Bibliography
- Gross, Nigel et al. Speed and Power: 100 Years of Change. North Vancouver, British Columbia, Canada: Whitecap Books, 1998. ISBN 1-5510-732-5.
- Hendrix, Lin. "Thunderscreech." Aeroplane Monthly Vol. 5, issue 8, August 1977
- Taylor, John W.R. and Kenneth Munson, . History of Aviation. London: Octopus Books, 1973. ISBN 0-7064-0241-3.
- Young, Mark C., ed.The Guinness Book of Records 1997. North Sakem, New York: Mint Publishers Group, 1997. ISBN 0-85112-014-8.
