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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
They only need to achieve 39 more minutes of flight time and they'll match the range of a 787!
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'!"
Isn't that close to reentry speed? What did they expect? If we had a cheap, durable, stable material that could stand up to that for any length of time we would have used it on the Space Shuttles and maybe kept them flying for another 10 years.
That's the point of DARPA. To figure out how to answer these sorts of questions.
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
So what the fuck is the alternative, then?
Um, it's a glider, launched from a rocket, which would probably use a hydrogen based rocket fuel or some other.. um.. why am I answering an AC?
WALSTIB!
And while they're busy doing that they often manage to put on one hell of a show:
* this effort
* the autonomous vehicle DARPA Challenge
* other random bits that we read about
* certainly other random bits we have no idea about, but I bet they're cool!
-nB
whois gawk date unzip strip find touch finger mount join nice man top fsck grep eject more yes exit umount sleep dump
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
Science and engineering are often advanced by never doing anything you are not absolutely certain will work perfectly.
/. articles should have this as the first comment.
Many, many
It seems we have completely forgotten the words 'trial and error', and 'that's interesting...'
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.
several points (not all covered here, these are just a few that immediately popped into my head):
-from the telemetry they can determine how exactly the materials and structure failed. From this better material and structure design for slower aircraft making them more survivable;
-from the telemetry they can determine the high stress points on a craft travelling at such a speed (I can imagine, the leading edges of the control surfaces, the wingtips and the nose will get stupendously hot and massive vortices spilling from the trailing edges may have had something to do with the failure of the superstructure). Again, this leads to improvements in aircraft design;
-from observation and telemetry they can determine the aerodynamic stresses at the moment of failure.
As lessons previously learned: in reinforced carbon composite skinning, it is known that several thin and continuous layers are far stronger than a single thick, segmented layer. This principle is used in hulls on sporting boats, as hull integrity at speed is kinda important. When we learn how to spin alloys into a contiguous undulating skin we'll be doing well.
Consider also that without such pioneers as Chuck Yeager we would not have transsonic or supersonic airliners. We would not know how to compensate for TS turbulence, or how differently control surfaces behave across the sound barrier, or how baffles slow intake air enough so as not to shatter fan blades, or most importantly, how the human body reacts to such unnatural velocities.
Operation Guillotine is in effect.
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.
I fly unmanned hypersonic aircraft. I would call these rockets spacecraft except they don't go to space.
I and nobody else flies "in" them. The temperatures are too high.
Even SS1 had a peak velocity of altitude adjusted 240 knots at sea level.
The goal here is a 1 hour to target RPV. Not a passenger aircraft and not Fedex to China. This is a military thing. Rediculous cost.
BTW you can see my M5 "aircraft" on the web anytime you want. Search for 152mm rocket in the USA. The 229mm one goes faster and the 457mm "can be manned", albiet not hypersonic. Just well above supersonic.
JJ
What's even cooler, that speed is close to orbital speed. So with little additional thrust this plane can make it into orbit!
Fortunately, we'll have disposable people riding in it.
Finally, a use for Intellectual Property Lawyers!
And while they're busy doing that they often manage to put on one hell of a show:
* this effort
* the autonomous vehicle DARPA Challenge
* other random bits that we read about
* certainly other random bits we have no idea about, but I bet they're cool!
-nB
also..
* the fucking Internet
you kids these days need to learn your history
ICBM systems are sunk costs. Some possible salvage value as booster stages, but basically the money is gone. Better to keep them functioning lest someone try to collect on our debt.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
You realize it was boosted to speed on a conventional rocket? Don't mistake an aerodynamic testbed for a working vehicle.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
Uhhh..we actually didn't have any way to know then because we hadn't reached 25 MPH but thanks to a guy that detached a retina for science we know pretty much EXACTLY what the human body can take and at what point you'll have serious damage. this is why we use see combat pilots in battle they flip over before diving because the human body tolerates positive Gs much better than negative.
So sure if you start out really slow and build up very gradually? Then even the fat guy in front of you in line at the Wendy's could handle a ride in the thing, its just a question of how long that build up and slow down would take and would it be worth the fuel. Considering how much gas the Concorde blew through i'm thinking probably not practical.
ACs don't waste your time replying, your posts are never seen by me.
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)