Slashdot Mirror
Armadillo Aero One Step Closer To Space
RobertB-DC writes "The folks at Armadillo Aerospace have taken another step toward the X-Prize, dropping their re-entry vehicle from 2000 feet with no major problems noted. As usual, the Armadillo crew documented the event with text, pictures and video, and the story is also covered by Space.com (though without as many cool technical details). It's a bumpy ride, though -- instruments recorded some 10 G's on touchdown."
Is armadilloaerospace.com already down?
Here's the google cache
http://www.armadilloaerospace.com/n.x/Armadillo/Ho me/Widget`s Corner?news_id=214
We finished up all of the prep work for the vehicle on Tuesday. We welded in strapping points to hold 600 pounds of passenger sandbags in the cabin area, and we mounted five 45 pound Olympic barbell plates on a peg at the end to simulate the weight of the final engines, plumbing, and backup recovery system that will be on the full size vehicle. We mounted four 2 throat engine shells as placeholders. Total weight is just under 2400 pounds. We use a combination of multiple chain hoists, a palette jack, and a forklift to move the full vehicle around and get it up on the trailer, but we did wind up breaking one of the castor wheels that we had mounted on our tank cradle. If we wind up having to use the 1600 gallon propellant tank (the current one is 850 gallons), we arent going to be able to stand the vehicle up under the main girder inside our shop, which will be inconvenient.
On Saturday, we headed out to our test site for the drop test. There were quite a few stares on the road in transit We had a few spatters of rain, and the wind occasionally gusted to 12 knots, but we were able to perform the drop in relatively calm 6 knot winds.
Anna rented a big RV for the day, which was very worthwhile. It was nice to be able to take a break in an air-conditioned space.
5 State Helicopters arrived with a big Sikorsky for the lifting. It was very convenient that they were based close by, and didnt have a problem with our unusual application (although they did have us contact the local mayor and sheriff for explicit permission). We were very impressed with the precision that they were able to do the lifting we were afraid that the vehicle might get dragged or bounced on the crush cone, which could buckle it before the test even started, but they were able to perfectly pivot it up on the nose, and gently lift it off the ground. If we had known they were that precise, we probably could have skipped renting the forklift truck for recovery and just had them lower the rocket back onto the trailer after the test.
We made several 18 diameter test parachutes that were weighted to drift at about the same rate that the full size parachute was expected to fall. We did the test drop from 1500 AGL, under the assumption that the big vehicle would fall several hundred feet before the main chute was fully deployed. The landing point for the test parachute was satisfactory, so we planned the full vehicle drop for 2000 AGL. Neil rode in the helicopter to do the parachute releasing, and Anna hung out the side of the helicopter (with a safety strap) to get aerial footage.
We had to abort our first attempt to drop the vehicle, because the line that we ran from the helicopter to the Sea-Catch toggle release above the rocket had wrapped itself around the chain so many times that Neil couldnt pull it hard enough to trigger the release. This was fixed by tying loose loops of plastic every few feet along the chain, which kept the pull-line in place.
On the second try, the release worked perfectly. You can clearly see the naturally unstable aerodynamics of the vehicle, as it starts to tip over almost immediately after release. We all held our breath as it started to fall, but the drogue immediately inflated and started pulling the main canopy out. It was nine seconds from release to full canopy inflation. The opening shock was negligible, barely hitting 2Gs. For high altitude flights, we are aiming for a 200 mph terminal velocity under the stabilizer drogue at the time of main canopy deployment, so opening shock will be much greater then.
The wake of the main canopy is so great that the deployment drogue just rests on the canopy during descent, without any inflation at all. The real deployment system will have a much longe
Depends on many milliseconds of duration. Humans have been shown to take 35 G's for very short durations (belted head on collision at 50 mph for example), but anything over about a 100 milliseconds and your organs (and bones) tend to go a little mushy.
[RIAA] says its concern is artists. That's true, in just the sense that a cattle rancher is concerned about its cattle.
John Carmack is a semi-regular poster to sci.space.policy on usenet; he's posted several times today with details of his test plans and schedules. Even if the company site is slashdotted, go do a Google Groups search on him and the sci.space.* groups and you'll get all his publically-available info, straight from the source.
It should actually be written "10 g's", with 'g' in lower case, as this refers to 10 times the normal acceleration, while "G" the capital letter refers to something entirely different.
You, sir, are an idiot.
As you can see from this link, the baseline for federal tests for preventing injury in automobile crashes is 130 G's-- this is after significant portions of the deceleration have been dampened by restraint systems and portions of the vehicle collapsing. Fighter pilots in pressure suits routinely pull 10Gs without even blacking out.
tm
Support TBI Research: http://www.raisinhope.org
BitTorrent of the Video here:
p Test.mpg.mpeg.torrent
http://www.bytemonsoon.com/download.php/11286/Dro
Whenever the offence inspires less horror than the punishment, the rigour of penal law is obliged to give way...
Stole from usenet group sci.space.policy:
8 &oe=UTF-8&threadm=c0e0a1dd.0307071735.5f09aa08%40p osting.google.com&rnum=1&prev=/groups%3Fq%3DThe%2B acceleration%2Bspikes%2Bwere%2Bonly%2B10G%252C%2Bw hich%2Bis%2Bnot%2Bmuch%2Bof%2Ba%2Bproblem%26ie%3DU TF-8%26oe%3DUTF-8%26hl%3Den%26btnG%3DGoogle%2BSear ch )
"M. Scott" wrote in message news:...
> John Carmack wrote:
> > We did the helicopter drop test of our X-Prize vehicle with parachute
> > system and crushable nose on Saturday.
>
> Great video! Congratulations on your progress and I look forward to
> reading about more of your exploits!
>
> I have one question, though. If there had been a man in the vehicle
> during that drop test, would he have been severely injured? The landing
> looked rough-- much rougher than in the SA'03 nose cone test, for
> instance.
The acceleration spikes were only 10G, which is not much of a problem
with a harness and padding. The roll-up-and-fall-back-down behavior
would certainly be pretty rough, so we hope to reduce that
behaviorwith some changes to the cabin top lip, the parachute, and the
tail supports.
The X-Prize could be had with the landing as-is.
John Carmack
Google link: http://groups.google.com/groups?hl=en&lr=&ie=UTF-
The problem is, those were G's realative to the person horizontally (perpendicular). When talking about vertical G's (parallel to the spine), a human can withstand far, far fewer G's. This is because our body isn't made to compress and the energy has to go somewhere. When taking G's head on, your body is good about bending and flexing to rid it self of the energy. When impacting vertically, pretty much the only mechanism your body has is to compress your spine. Pilots who land harshly often find themselves inches shorter and a life time of back and body problems.
I keep seeing people quote those high g numbers from historic tests of days past. One of the most critical factors in determining how fatal a g rating is on a human, is not only the g's, but the duration the g's were sustained. For example, a human can take insanely high g's over a very finite duration. Those same g's which may of only bruised and bloodied your body may have killed you if the same g's were sustained for twice the duration.
"Okay, i gotta know, what's the highest known G force _involuntarily_ encountered by a human, and how exactly did it happen? "
I belive some race car drivers have experianced 100 G's in crashes. Ones where the slammed into the outer wall at nearly full speed (ala 200mph). I remember some TLC or discovery special investigating how a driver survived such a crash.
10 G's isn't to bad. Jet fighter pilots can pull 4-5 G's momentarily before blacking out. Those 10 G's would be very very short, not like holding a high speed turn for a while. I think some roller coasters pull 3-4 G's in some turns as well.