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Hypersonic Test Aircraft Peeled Apart After 3 Minutes of Sustained Mach 20 Speed
coondoggie writes "DARPA's experimental Hypersonic Technology Vehicle (HTV-2), lost significant portions of its outer skin and became uncontrollable after three minutes of sustained Mach 20 speed last August. That was the conclusion of an independent engineering review board investigating the cause of what DARPA calls a 'flight anomaly' in the second test flight of the HTV-2. Quoting the report: 'The resulting gaps created strong, impulsive shock waves around the vehicle as it traveled nearly 13,000 miles per hour, causing the vehicle to roll abruptly. Based on knowledge gained from the first flight in 2010 and incorporated into the second flight, the vehicle's aerodynamic stability allowed it to right itself successfully after several shockwave-induced rolls. Eventually, however, the severity of the continued disturbances finally exceeded the vehicle's ability to recover.'"
Right. Glad you grasped the point of the project so well, and didn't try to wedge in some off-topic nonsense.
The technology exhibited here is completely independent of the fuel source on which it runs. Your comment misses the point.
This is slashdot. The only point of comments now is off-topic nonsense, hopefully modded 'informative'
As a person who flies hypersonic aircraft for a living this is notable on several layers.
1. They did a test and it went far past hypersonic (M5).
2. They achieved M20, altitude adjusted
3. All that happened after 3 minutes is the materials failed
4. It lasted 3 minutes!
To me this is a stupendous success.
I am a hyper-critic of most of the hypersonic tests we all hear about.
Spend more money on this.
JJ
And scientifically, it went around 750 miles in 3 minutes. In an atmosphere. That's a pretty damn awesome piece of engineering.
"Little does he know, but there is no 'I' in 'Idiot'!"
Yes. Science and engineering are often advanced by never doing anything you are not absolutely certain will work perfectly.
Why yes, I AM a rocket scientist!
When you say the fuel source doesn't matter, are you referrring to sustaining speeds of Mach 20, or to the plane's Rapid Unscheduled Disassembly feature?
Except for the fact it runs on hydrogen peroxide and methanol. Plus, I'm given to understand the proposed full scale version would run on hydrogen slush and LOX.... aka rocket fuel.
Fortunately, we'll have disposable people riding in it.
How can we continue to believe in a just universe and freedom to eat crackers if we have no ale?
IMHO, this was not a failure, just another step forward. We learned something useful, to be explored/applied next.
Good job, folks! Keep moving forward....
Down With Slashdot BETA!!! I've been around the corner and seen the oliphant; you can only abuse me from your perspecti
If advanced planes work perfectly, we will never get a Bionic Man.
The Kruger Dunning explains most post on
640mi (in 3 min) should be enough for anyone.
So just slow it to Mach 19.7.
make imaginary.friends COUNT=100 VISIBLE=false
And scientifically, it went around 750 miles in 3 minutes. In an atmosphere. That's a pretty damn awesome piece of engineering.
Meteors do that every day. And, they have the same end result.
Some mornings it's hardly worth chewing through the restraints to get out of bed.
Here's the actual press release (which Network World just cut-and-pasted): http://www.darpa.mil/NewsEvents/Releases/2012/04/20.aspx
But Mach 20? Really? Does it really serve a purpose other than finding out that we can push the limits of things?
Purpose? Probably to build a long-range bomber that can hit a target anywhere on Earth a few minutes after it's been identified. Or to build a vehicle that can reach low Earth orbit and return. Or maybe just to see what's humanly possible.
What I really want is a bicycle powered, mach 20 vehicle. And a unicorn. And some waffles.
Oliver's law of assumed responsibility: If you're seen fixing it, you will be blamed for breaking it.
If you can go that fast in an atmosphere, you can use an air-breathing engine to get you most of the way to LEO...
Can you be Even More Awesome?!
This close to the bleeding edge, definitely. We have better models and more teraflops to run them than ever before, but real breakthroughs come from unexpected, unintuitive results. Remember how hard it was for most engineers to believe that mere foam could bash in a shuttle wing - until they fired an actual piece of foam at an actual leading-edge panel?
Flying real hardware is still the only way to conclusively
1. Learn Something (if it has problems) or
2. Silence the critics (if it works fine).
IMHO, while a good number of aerospace contracts can be criticized for either being pork or thinly veiled airliner-maker subsidies, that should be focused on those never producing an instrumented flight.
It depends on how long it takes to get to those speeds. At 9.8m/s^2, easily handled as evident from people parachuting, it would take about 11 minutes to reach mach 20. Once you reach that speed, there's no problem going that fast just because of speed...spacecraft have been doing that for some time. Apollo 10 holds the record for fastest manned vehicle at nearly 25,000MPH.
According to the g-force wiki page, early experiments showed that untrained individuals could survive 17g's accelerating and 12g's decelerating (in a facing forward orientation) which would translate to 40 and 56 seconds respectively.
The maximum recorded g's sustained by a person for more then a split second is 46.2g's and it would take 14.5 seconds of acceleration or deceleration to match that rate.
The hard part about going that speed is the friction and stresses on the aircraft flying through the atmosphere.
Fortunately, we'll have disposable people riding in it.
Finally, a use for Intellectual Property Lawyers!
In theory, yes. The type of design (a "waverider") places the hypersonic shockwave directly beneath the vehicle. Basically, you're surfing the shockwave. This reduces the stresses involved, improves stability and should allow considerably more control than could be achieved with the space shuttle (you have sufficient lift from a waverider to glide). Waveriders do have disadvantages - most designs only work at specific speeds, the wings have a habit of frying and they rely on cooling by radiation (only effective at high altitude).
Old wisdom on waveriders:
http://research.lifeboat.com/surf.htm
http://www.aerospaceweb.org/design/waverider/waverider.shtml
Published theory:
http://www.waset.org/journals/waset/v79/v79-79.pdf
http://www.dept.aoe.vt.edu/~mason/Mason_f/ConfigAeroHypersonics.pdf
Multi-speed waveriders:
http://www.springerlink.com/content/x75nh2154nuh5464/
Amateur waverider research:
http://www.gbnet.net/orgs/staar/waveriders.html
NB: The STAAR group beat NASA and the US DoD to the first working waverider airfoil, as noted on their site. Perhaps NASA's problem with their current design is that they're not threatening the engineers with bagpipe music.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)