Fastest propeller-driven aircraft

They are also extremely unlikely, due to the complex aerodynamic problems of propeller driven aircraft approaching the speed of sound.

Also not formally accepted by the FAI, which was not present due to wartime conditions, are speeds recorded in a dive during high-speed tests with the Supermarine Spitfire, including Squadron Leader J.R. Tobin's 606 mph (975 km/h) in a 45° dive in a Mark XI Spitfire (date unknown) and Squadron Leader Anthony F. Martindale's breaking 620 mph (1,000 km/h) (Mach 0.92) in the same aircraft in April 1944.

Rapid advances in first liquid-fueled rocket engine-powered aircraft – with a 1,004 km/h (624 mph) record set in October 1941 by a German example — and axial-flow jet engine technology during World War II meant that no propeller-driven aircraft would ever again hold an absolute air speed record.

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.

The Guinness Book of World Records lists the Soviet Tupolev Tu-95 bomber and its derivatives (Tu-114 and Tu-142) as "the fastest propeller-driven aircraft in standard production form", with a maximum cruise speed of 925 km/h (575 mph; 499 kn) or Mach 0.82.

[5]Even earlier, in 1997, the Guinness Book of World Records listed the Republic XF-84H Thunderscreech experimental USAF fighter as the fastest propeller-driven aircraft, with a speed of 1,003 km/h (623 mph; 542 kn) or Mach 0.83.

[6] While it may have been designed as the fastest propeller-driven aircraft, this goal was never realized due to severe stability problems.

In 1925 U.S. Army Lt. Cyrus K. Bettis flying a Curtiss R3C won the Pulitzer Trophy Race with a speed of 248.9 mph (400.6 km/h).

The fastest German propeller-driven aircraft that flew in WWII (but which did not see combat) was the twin-DB 603-powered Dornier Do 335 Pfeil ("Arrow") which had a claimed top speed of 474 mph (763 km/h).

[20] In the 1950s two turboprop tailsitter fighter prototypes were designed for the US Navy, the Convair XFY "Pogo" (610 mph (980 km/h)) and the Lockheed XFV (578 mph (930 km/h)), but both had less powerful engines than intended[21][22] and conflicting demands of vertical and horizontal flight further compromised flight speeds[23] so they never got close to these numbers.