Aircraft Speed Records

What is the fastest jet on earth?

- question from name withheld

Since this article was originally published, the SR-71's speed record has been broken by NASA's X-43 Hyper-X experimental aircraft. This unmanned vehicle was designed to test an experimental engine called a scramjet at speeds ranging from Mach 7 to Mach 10. At the X-43's cruising altitude of 100,000 ft (30,510 m) , these Mach numbers correspond to speeds of approximately 4,750 mph (7,640 km/h) to 6,750 mph (10,855 km/h) .

The scramjet, which stands for supersonic combustion ramjet, is a subclass of the jet engine. However, the X-43 was accelerated to these high Mach numbers by a booster rocket, and the aircraft only flew under scramjet power for a few seconds before falling into the sea. From a purist's point of view, the X-43 did not truly break the jet-powered aircraft speed record since it was incapable of cruising at and sustaining these high speeds.

Nonetheless, some believe the SR-71's speed record has already been bested by its supposed replacement dubbed the Aurora. If this mysterious new spy plane does indeed exist, it is believed to cruise at speeds ranging from Mach 5 to Mach 8 at 100,000 ft (30,510 m) . These Mach numbers correspond to speeds of 3,380 mph (5,435 km/h) to 5,400 mph (8,685 km/h) . The Aurora may use scramjets, pulse-detonation wave engines, or some other exotic form of propulsion to reach these speeds. However, we should stress that there is no conclusive evidence that this plane ever existed.

As of the writing of this answer, the official speed records for the fastest flying animals and machines are listed below.

Class Record Setter Speed Date Set Insect Australian Dragonfly 36 mph

(58 km/h) n/a Bird (level flight) Red-Breasted Merganser 80 mph

(129 km/h) n/a Bird (dive) Peregrine Falcon 217 mph

(349 km/h)

in a 45° dive n/a Autogyro WA-116F 120.5 mph

(193.76 km/h) 18 September 1986 Rotorcraft Westland Lynx 249.10 mph

(400.55 km/h) 11 August 1986 Biplane Fiat CR42B 323 mph

(520 km/h) 1941 Piston-Powered Seaplane Macchi MC72 440.68 mph

(709.21 km/h) 23 October 1934 Piston-Powered Aircraft Grumman F8F Bearcat 528.33 mph

(849.55 km/h) 21 August 1989 Turboprop-Powered Aircraft Tupolev Tu-114 545.07 mph

(876.47 km/h) 9 April 1960 Jet-Powered Flying Boat Beriev M-10 566.69 mph

(911.24 km/h) 7 August 1961 Jet-Powered Aircraft Lockheed SR-71A 2,193.16 mph

(3,326.60 km/h)

Mach 3.3 28 July 1976 Rocket-Powered Aircraft North American X-15A-2 4,520 mph

(7,274 km/h)

Mach 6.72 3 October 1967 Winged Vehicle Space Shuttle Columbia

on re-entry ~ 17,000 mph

(27,340 km/h)

Mach 25 14 April 1981 Manned Vehicle Apollo 10 capsule

on re-entry ~ 24,790 mph

(39,885 km/h)

Mach 36 26 May 1969 Interplanetary Vehicle Voyager 1 ~ 38,600 mph

(62,070 km/h) launched

5 September 1977 Manmade Object Helios 2 ~ 150,000 mph

(241,350 km/h) 17 April 1976

Note that the insect record is still the subject of much debate since it is difficult to reliably measure the speed of a flying insect with repeatability. The dragonfly speed has been measured fairly consistently, though some sources indicate even higher speeds of up to 43 mph (70 km/h) have been recorded. Smaller species of insects are more difficult to measure as demonstrated by an entomologist who claimed to have clocked a deer botfly at 800 mph (1,290 km/h), faster than the speed of sound! Though this record has since been debunked due to poor experimental practices, more recent investigators have measured the tabanid fly at 90 mph (145 km/h).

Speed records for birds are also subject to controversy as different sources claim the fastest is the swift, the pergrine falcon, or the frigate bird. Again, the red-breasted merganser (a species of duck) seems to be the most consistent and repeatable record. However, one researcher claims to have measured a spine-tailed swift at 106 mph (170 km/h). The true record-holder often depends on how the speed was measured and the exact wording of the record.

- answer by Doug Jackson, 22 April 2001

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