Hypersonic jet ready for launch (BBC)

[eppur_se_muova]

Hypersonic jet ready for launch
Jonathan Fildes
BBC News science and technology reporter

A new jet engine design able to fly seven times the speed of sound is scheduled to launch over Australia on Friday.

The scramjet engine, known as Hyshot III, has been designed by British defence firm Qinetiq.
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On its descent the engine is expected to reach a top speed of Mach 7.6 or over 9,000km/ hour.
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If the test flight is successful, it will be followed four days later by the test flight of another Hyshot engine designed by the Japanese Aerospace Exploration Agency (Jaxa). This will be followed in June by the launch of an engine that will fly at Mach 10, designed by the Australian Defence Science and Technology Organisation (DSTO).
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more: http://news.bbc.co.uk/2/hi/science/nature/4832254.stm

[Geoff R. Casavant]

1. Ah, my scientific nit-picking rears its ugly head

Mr. Fildes needs to brush up on his jargon.

A "hypersonic" jet makes a noise too high for humans to hear, which I doubt is the case here. A jet that goes really really fast is a "supersonic" jet.

I knew my days as a high school geek would not be wasted.

[eppur_se_muova]

2. Ummm...I'm thinking ultrasonic = high frequency, hypersonic = high speed

[Geoff R. Casavant]

3. Ugh! My bad all around!

With you that ultrasonic means high-F.

Then, as it turns out, supersonic is used for speeds from Mach 1 to 5, and hypersonic is Mach 5+. This plane is Mach 7, so hypersonic is more accurate. The last time I heard these terms was talking about the Concorde SST, which only went Mach 2 and was therefore truly supersonic -- the only place I ever heard hypersonic used in a sentence was comic books.

Never said I was a particularly good geek.

I'm going to go hide my face in shame now.

[Dead_Parrot]

4. Interesting definition...

If this thing smacks into the desert at mach 7, it's a success.