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NASA's X-43A Vehicle Ready for Flight
Aielman writes "NASA has set March 27 as the date for testing the X-43A vehicle over a Navy range in the Pacific. It will be testing a non-rocket air breathing scramjet engine at approximately 5,000 mph. This is the second attempt, the first ending in intentional destruction due to course deviations shortly after launch."
Although ramjets have been around for decades, they've generally been used at speeds of around Mach 1-3. The BOMARC webpage gives a good example, with a speed of just under 2000 mph. Scramjets might one day be developed to work well at around Mach 5-10, but it's been a tricky problem for engineers to solve.
Scramjet combustion is tricky because the fast air flow can easily blow out the flame. Imagine blowing gently on a small match flame to increase the flame versus blowing strongly on a candle flame to put it out.
Also the shape of the scramjet generally favours a "sweet-spot" in air pressure (altitude) and speed. This makes them OK for cruise missiles, but not so good for orbital launch rockets. You can try variable geometry (change the shape of the inlet/nozzle) but that means some machinery, which adds weight to the system.
That brings me onto another problem - thrust/weight ratio. Rocket engines get much higher thrust/weight ratios than air breathing engines. The best air-breathing thrust-weight design that I've seen is Skylon's SABRE (not a ramjet) which will be nice if they can ever build it.
This is not a sig
This link provides some more information on the project.
Dewey, you fool! Your decimal system has played right into my hands!
That is, in fact, faster than the fastest speeding bullet (how fast is a speeding bullet?) So what could you do with a vehicle that fast?
Actually it's not. There is a special projectile/gun type which can reach hypersonic speeds and that is the railgun (no joke). The difference is that the rail gun accelerates in vaccum by electormagnetic means and can easialy reach 5000+ MPh. The US army is experimenting with the thing (which is Huge if large speeds is to be attained) and are planning to build some sort of tank killer using just the kinetic kill principle.
For reference look Here or here
Yours Yazeran
Plan: To go to Mars one day with a hammer.