Fastest propeller-driven aircraft

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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, but these speeds are not included as accepted records.

Contents

• 1 Propeller versus jet propulsion
• 2 Turboprops
• 3 Piston engines
• 4 Other claimants
• 5 See also
• 6 References

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, and there are certain hybrid types like the Motorjet that use a piston engine to drive the compressor of a jet engine, which supplies the primary thrust (although some types also have a propeller powered by the piston engine for low speed efficiency). All aircraft prior to World War II (except for a tiny number of early jet aircraft and rocket aircraft) 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.

Turboprops

Tupolev Tu-114

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 aircraft in the world, a record it has held since 1960.^[1][3]

McDonnell XF-88B experimental fighter

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.

XF-84H "Thunderscreech"

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.

Piston engines

Rare Bear, world speed record holder

The more "traditional" class of propeller-driven aircraft are those powered by piston engines, which include 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 official speed record for a 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, Nevada, United States of America.^[8][9]
The FAI record for the fastest piston-powered aircraft over a long-distance circuit is the 2000-km record of 720.13 km/h (447.47 mph) set on 22 May 1948 by Jacqueline Cochran in a P-51C. (She also holds the 100-km record of 755.67 km/hr, set in December 1947.) Higher speed records exist; some are unofficial and some were officially-timed one-way trips aided by tailwinds. Examples of the latter: a B-29 averaged 725 km/hr from Burbank to Floyd Bennett Field (3957 km in 5.455 hours) on 11 December 1945, and Joe DeBona averaged 904 km/hr from Los Angeles LAX to New York Idlewild (3981 km in 4.405 hours) in a P-51 on 30 March 1954.

Other claimants

The 1903 Wright Flyer did 48 km/h (30 mph) during its first flight; the Bleriot XI reached 75 km/h (47 mph) in 1909. Fabric-covered biplanes of the World War I era and shortly after could do up to 320 km/h (200 mph). In 1925 U.S. 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).^[10]
Speeds of all-metal monoplanes of the 1930s 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), still the record for piston-powered seaplanes.^[11] The Messerschmitt Me 209 V1 set a world speed record of almost 756 km/h (470 mph) on 26 April 1939,^[12] and the Republic XP-47J (a variant of the P-47 Thunderbolt) is claimed to have reached 813 km/h (505 mph) in testing^{[citation needed]}. A prototype of the successor to the Supermarine Spitfire, the Supermarine Spiteful F.16 (RB518), reached 494 mph (795 km/h). The fastest German propeller driven aircraft to see combat in WWII was the Dornier Do 335 "Pfeil" which had a top speed of 474 mph (763 km/h).^[13]
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.

Republic P-47J reached 505 mph in testing

Convair XFY-1 "Pogo"

Lockheed XFV-1 "Salmon"

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. 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. The Lockheed XFV was fitted with a less powerful engine than it was designed for and had makeshift non-retractable landing gear for horizontal takeoff and landing;^[14] the Convair's landing gear supported it in a vertical position. It was usually flown with the cockpit open, since the ejection seat was thought unreliable.^[15] These aircraft had "compromised in-flight speed" because of the conflicting demands of vertical and horizontal flight.^[16]

See also

• List of vehicle speed records