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USAF Scramjet Hits Mach 6, Sets Record
s122604 writes "The [X-51A Waverider]'s scramjet engine accelerated the vehicle to Mach 6, and it flew autonomously for 200 seconds before losing acceleration. At that point the test was terminated. The Air Force said the previous record for a hypersonic scramjet burn was 12 seconds. Joe Vogel, Boeing's director of hypersonics, said, 'This is a new world record and sets the foundation for several hypersonic applications, including access to space, reconnaissance, strike, global reach and commercial transportation.'"
Proof of concept. Scientists can only go so far on theory ( and it's impressive how far they do go ). At some point their research hits a point where they need to perform experiments.
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Keep in mind that at mach six 200 seconds is 400 kilometers. That's already enough range to make a useful weapon (and yes I realize there was some acceleration time in there). Heck, that's already longer range than the most advanced missiles that many countries have. Increase the stability to just 10 minutes of burn time and you've got a missile that can go 5% of the way around the world.
Commercial applications do usually follow. Whether or not you agree with it, military research has led to an enormous number of scientific advances that were initially used by the military but later disseminated more broadly. Jet engines, the Internet, cryptography, GPS, nuclear reactors, etc. Mach 6 might be inefficient overkill for Earth-side transportation, but it may provide a viable means of launching spaceflights one day.
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Boeing announcement here:
http://boeing.mediaroom.com/index.php?s=43&item=1227
"In its first flight attempt, the Boeing [NYSE: BA] X-51A WaveRider today successfully completed the longest supersonic combustion ramjet-powered flight in history -- nearly three and a half minutes at a top speed of Mach 5."
My understanding is that it didn't reach the 300 seconds Mach 6 burn it was hoping for. 200 seconds and Mach 5 isn't all that bad though...
More here:
http://www.theregister.co.uk/2010/05/27/x51_first_shot/
wot no sig
Scramjets aren't exactly easy to test in the lab.
Hell, even normal jet engines are tough to test. Have you seen the equipment used to keep those things stationary while testing them? Holy fuck .
Living With a Nerd
Fine. Except for jet engines, the Internet, cryptography, GPS, and nuclear reactors what has the military done for us?
No it isn't. Mach is the speed sound travels in a medium (the atmosphere). As there is no atmosphere in orbit, you can't associate a mach speed value to orbital velocities.
-SaNo
Except they're not recovering these vehicles for analysis.
Like incandescent light bulbs?
Go green: turn off your refrigerator.
Mac 5 melts aluminum steadily
Mac 6 melts steel
And don't forget that keeping this friction heat down also requires a good deal of power.
It uses it's own shockwave for lift, not propulsion. This does, however, help it go faster, by eliminating the drag that adding wings would cause.
# cat
Damn, my RAM is full of llamas.
Hello,
The story is in error. Per this link, the plane only hit Mach 5, not Mach 6. This is still a pretty successful test, however.
Link: http://www.msnbc.msn.com/id/37377401/ns/technology_and_science-space/
--PeterM
Even at Mach 3, you want a layer of foam to avoid burning.
Let's not stir that bag of worms...
The scramjet will circulate the fuel behind engine walls to cool the structures. Without such active cooling, the temperatures in a scramjet could reach 5,000 deg. Fahrenheit, high enough to melt virtually any metal on Earth. Solving the cooling challenge is a major AFRL/Pratt & Whitney achievement.
Source
My wager is that the entire vehicle took thermal control into its design considerations and it uses a combination of geometry, aerodynamics, and fuel management to help sink heat at an appropriately high rate to prevent too much for a build up. However, since I don't have the design specs, and I doubt anyone outside of the military will, for awhile at least, I can only speculate. You also have to understand that at those speeds, your gas dynamics become a problem of rarified gasses and heat management becomes a very tricky problem indeed, one that can't be approached by traditional cooling means. So in summation I would guess yes, they have probably found some very cool new ways to sink heat at hypersonic speeds.
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It's all part of the Prompt Global Strike program. Eventually the goal is to have scramjet powered missiles with a range of 12000+ miles. Allowing you to fire an obviously non-nuclear missile from Kansas to North Korea and have it hit the target in less than 3 hours. Basically, even launching a B2 for a direct strike takes days or weeks. Refueling planes need to be put into the air, mission plans drawn up, clearance over foreign airspace cleared, pilots briefed, etc. They want to be able to say "Fire" and have the missile in the air within minutes and at target within hours; with the added benefit of not putting any American lives in harms way.