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.

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

Related Topics:

What is the fastest four-engine propeller-driven plane in the world?

I remember there was a seaplane called the Sea Dart. Wasn't it faster than the Russian jet seaplane developed by Beriev? Isn't the Sea Dart the fastest seaplane in history?

What is the fastest passenger aircraft on commercial flights? What is the speed of Concorde?

What is the world's fastest fighter plane? What country built it?

Your site mentions a vehicle called Helios that reached 150,000 mph. What is the Helios?

Doesn't the Pluto New Horizons spacecraft now own the fastest manmade object record?

How long would it take Earth's fastest space ship to reach Proxima Centauri? If one of the old Pioneer or Voyager probes was discovered, would it be so badly contaminated by radiation that it could not be safely recovered for analysis?

Read More Articles:

• Current Question of the Week
• Past Question Archive
• Most Popular Questions
• Search the Archive
• Submit a Question

	Aircraft | Design | Ask Us | Shop | Search
	About Us | Contact Us | Copyright © 1997-2023