Raptor Aircraft

Datadriver said:
The fact that the gear sheared off is pretty good indication that he should have just geared-up. I understand he was cruising pretty low, probably not much time to debate the physics.
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Not really. From a safety stand point you want to dissipate energy during a crash over as long of a time period as possible. That whole F= ma and a = v/t thing. Shearing the gear off would have reduced some of the energy where keeping it up wouldn't.
 
Datadriver said:
The fact that the gear sheared off is pretty good indication that he should have just geared-up. I understand he was cruising pretty low, probably not much time to debate the physics.
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Personally, I think the fact that he put his valuable one-off R&D airplane in cornfield suggests that perhaps he should have been flying at a higher altitude, so that when the very, very predictable trouble raised it's ugly head he'd have some alternatives. Yes, he came out of it OK, and the airplane did surprisingly well for having crashed in a corn field. My hats off to whoever did the engineering, I suspect it wasn't the pilot. All this said I'd say he got off lucky indeed. Lots and lots of places that outcome would've been nowhere near so benign.
 
steingar said:
Personally, I think the fact that he put his valuable one-off R&D airplane in cornfield suggests that perhaps he should have been flying at a higher altitude, so that when the very, very predictable trouble raised it's ugly head he'd have some alternatives. Yes, he came out of it OK, and the airplane did surprisingly well for having crashed in a corn field. My hats off to whoever did the engineering, I suspect it wasn't the pilot. All this said I'd say he got off lucky indeed. Lots and lots of places that outcome would've been nowhere near so benign.
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I think if he could have had more altitude, he would have. That said, this project was supposed to be in the flight levels. Why he decided to attempt to fly through the Rockies with that service ceiling, with a psru that was allegedly going to be scrapped and had already failed once is a question for Peter to the FAA/ntsb. If the project was sold, it should have been trucked to Idaho. Would have gotten there faster.
 
Racerx said:
I think if he could have had more altitude, he would have.
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What bugs me more than little bit is he was allowed to fly this rather dangerous contraption into conditions that were downright dangerous for those on the ground. He managed to kill no more than some corn stalks, but that just didn't have to be. Part of the job of the FAA is to protect the American public from poorly built widgets falling from the skies. I'd say they rather dropped the ball on this one.
 
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steingar said:
What bugs me more than little bit is he was allowed to fly this rather dangerous contraption into conditions that were downright dangerous for those on the ground. He managed to kill no more than some corn stalks, but that just didn't have to be. Part of the job of the FAA is to protect the American public from poorly built widgets falling from the skies. I'd say they rather dropped the ball on this one.
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Maybe if he tried to get training they would have noticed.
 
steingar said:
What bugs me more than little bit is he was allowed to fly this rather dangerous contraption into conditions that were downright dangerous for those on the ground. He managed to kill no more than some corn stalks, but that just didn't have to be. Part of the job of the FAA is to protect the American public from poorly built widgets falling from the skies. I'd say they rather dropped the ball on this one.
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Um, you do realize what happens after any exp build, yes?
 
steingar said:
What bugs me more than little bit is he was allowed to fly this rather dangerous contraption into conditions that were downright dangerous for those on the ground. He managed to kill no more than some corn stalks, but that just didn't have to be. Part of the job of the FAA is to protect the American public from poorly built widgets falling from the skies. I'd say they rather dropped the ball on this one.
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Unless he got a ferry permit, the plane's operating limitations did not allow flight beyond 50 nm from KVLD. I don't know what else the FAA could have done on this one.
 
steingar said:
What bugs me more than little bit is he was allowed to fly this rather dangerous contraption into conditions that were downright dangerous for those on the ground. He managed to kill no more than some corn stalks, but that just didn't have to be. Part of the job of the FAA is to protect the American public from poorly built widgets falling from the skies. I'd say they rather dropped the ball on this one.
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I agree. And someone apparently ratted on him busting his limitations so either he got a permit or more likely decided "it's an experimental aircraft, I can do what I want"
 
Racerx said:
I agree. And someone apparently ratted on him busting his limitations so either he got a permit or more likely decided "it's an experimental aircraft, I can do what I want"
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The FAA has been after a poster here twice for BS that showed up on the internet. Methinks they could have done more.
 
EdFred said:
Not really. From a safety stand point you want to dissipate energy during a crash over as long of a time period as possible. That whole F= ma and a = v/t thing. Shearing the gear off would have reduced some of the energy where keeping it up wouldn't.
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Wouldn't shearing the gear off dissipate energy over a shorter time period? Seems like with gear up it would have slid through a few more rows of corn before stopping, dissipating the energy over a longer time period.
 
231TC said:
Wouldn't shearing the gear off dissipate energy over a shorter time period? Seems like with gear up it would have slid through a few more rows of corn before stopping, dissipating the energy over a longer time period.
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Unless the plane stopped IMMEDIATELY and concurrently with the gear shear, no. Did the plane not slide/bounce/whatever after the gear came off?
 
If he’d been higher, he might’ve gotten to an airport. But flying higher wasn’t an option. Looked at a certain way, this is just the CFIT that was inevitably coming with the plan he had. Of the outcomes that were realistically available, landing in corn is better than hooking a power line while getting gradually closer to some interstate in Idaho.
 
OneCharlieTango said:
If he’d been higher, he might’ve gotten to an airport. But flying higher wasn’t an option. Looked at a certain way, this is just the CFIT that was inevitably coming with the plan he had. Of the outcomes that were realistically available, landing in corn is better than hooking a power line while getting gradually closer to some interstate in Idaho.
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Why couldn't he fly higher? He'd done so previously. Maybe not as high as he should have been, but higher than he was.
 
Salty said:
Why couldn't he fly higher? He'd done so previously. Maybe not as high as he should have been, but higher than he was.
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He had done so previously but I assume it was on less weight. These cross countries were his first times with more fuel.


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Peter Anderson said:
He had done so previously but I assume it was on less weight. These cross countries were his first times with more fuel.


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Perhaps. If true, it just makes any part of the decision to make this trip all the more puzzling.
 
EdFred said:
Unless the plane stopped IMMEDIATELY and concurrently with the gear shear, no. Did the plane not slide/bounce/whatever after the gear came off?
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Sorry, I'm not following. Shearing the gear off dissipated energy quickly. No, not ALL of the energy, but enough to shear the gear off. Seems like NOT shearing the gear off would dissipate energy less quickly.
 
231TC said:
Sorry, I'm not following. Shearing the gear off dissipated energy quickly. No, not ALL of the energy, but enough to shear the gear off. Seems like NOT shearing the gear off would dissipate energy less quickly.
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Whatever energy it took to shear the gear off will no longer be transferred throughout the rest of the dissipation. It reduced the mass of what's left traveling forward, and it has reduced the speed slightly. If the gear was kept retracted, that energy isn't lost. Losing energy during a crash is a good thing.
 
EdFred said:
Whatever energy it took to shear the gear off will no longer be transferred throughout the rest of the dissipation. It reduced the mass of what's left traveling forward, and it has reduced the speed slightly. If the gear was kept retracted, that energy isn't lost. Losing energy during a crash is a good thing.
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Losing energy in a crash is an absolute. You will lose all the energy in the crash no matter what. It's how the energy loss is distributed across time that makes the difference.

The question is, did shearing off the gear spread the energy loss better? I don't know.
 
Salty said:
Losing energy in a crash is an absolute. You will lose all the energy in the crash. It's how long it takes to lose that energy that makes the difference.
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Correct, but losing it to the loss of gear, wings, whatever else might get shedded before you come to a stop is what you want. The Nascar crashes that look the worst (airborne and tumbling) generally result in the least injuries to the driver. Granted a plane doesn't have a roll cage like a stock car does, and you'll get rattled around inside if you tumble. But you want the gear shared off rather than not. Every little bit helps. You want that energy transferred everywhere else it can be besides you.
 
EdFred said:
Correct, but losing it to the loss of gear, wings, whatever else might get shedded before you come to a stop is what you want. The Nascar crashes that look the worst (airborne and tumbling) generally result in the least injuries to the driver. Granted a plane doesn't have a roll cage like a stock car does, and you'll get rattled around inside if you tumble. But you want the gear shared off rather than not. Every little bit helps.
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Personally, I don't think it's as simple as this.

If the gear is sheared of and that causes the nose to dig into the earth and stop you cold 2 feet later, I think you're better off sliding another 100 feet with the gear intact.
 
I've pondered this a million times, and I still don't know which way I'll go if I ever get into that situation. I'd be inclined to put the gear down, most likely.
 
Salty said:
Personally, I don't think it's as simple as this.

If the gear is sheared of and that causes the nose to dig into the earth and stop you cold 2 feet later, I think you're better off sliding another 100 feet with the gear intact.
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No disagreement there. I am assuming the plane continues to slide after the gear shear.
 
Salty said:
Losing energy in a crash is an absolute. You will lose all the energy in the crash no matter what. It's how the energy loss is distributed across time that makes the difference.

The question is, did shearing off the gear spread the energy loss better? I don't know.
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How could it not. If the gear is safely tucked its just more mass. Having it ripped off consumed at least some energy and reduced the mass. All of that is good. No bad. The only question is how much not if.
 
Salty said:
Personally, I don't think it's as simple as this.

If the gear is sheared of and that causes the nose to dig into the earth and stop you cold 2 feet later, I think you're better off sliding another 100 feet with the gear intact.
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Unless there's something in that next 100' which would decapitate you (or make the airplane go boom).

I think the bottom line is that there is usually no way to know exactly what the condition of the ground is from the air to correctly decide gear up or gear down until it's too late. So unless you're over water or a piece of land that you just happen to know the condition of, the better choice is gear down.

Either way, you have a 50/50 shot at getting it right... or wrong. ;)
 
Why didn't he use the whole-aircraft parachute? Was he not high enough or was it not operational? Or did he think he could manage a clean landing? Just curious.
 
It was (like almost every aspect of this aircraft) untested so he probably figured it was safer to flying it in.

Or maybe it wasn't even hooked up. Or not installed. Or maybe he forgot about it.

I'm sure when he posts the video he'll explain his logic.
 
donjohnston said:
It was (like almost every aspect of this aircraft) untested so he probably figured it was safer to flying it in.

Or maybe it wasn't even hooked up. Or not installed. Or maybe he forgot about it.

I'm sure when he posts the video he'll explain his logic.
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I think that the parachute was not actually installed. I could be wrong. It's discussed in this thread, somewhere between page 1 and page 85. But I will say, in spite of saying above that I will not second-guess his decisions between loss of thrust and the ground, that I wouldn't have pulled chute at 1,000 AGL. It's safer to dead-stick it into a cornfield under some control than hope the parachute deployment envelope extends that low.
 
dfw11411 said:
Why didn't he use the whole-aircraft parachute? Was he not high enough or was it not operational? Or did he think he could manage a clean landing? Just curious.
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Very good question!
 
iamtheari said:
I think that the parachute was not actually installed. I could be wrong. It's discussed in this thread, somewhere between page 1 and page 85. But I will say, in spite of saying above that I will not second-guess his decisions between loss of thrust and the ground, that I wouldn't have pulled chute at 1,000 AGL. It's safer to dead-stick it into a cornfield under some control than hope the parachute deployment envelope extends that low.
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I have to agree with you. Cirrus has done extensive testing on Their system. The envelope. Is well documented on a cirrus. In this thing who knows if the handle would even fire it.
 
Parachute is installed, but I wouldn't have used it either. If the plane is still flyable and you don't know that the parachute will work, keep flying.
 
Salty said:
Personally, I don't think it's as simple as this.

If the gear is sheared of and that causes the nose to dig into the earth and stop you cold 2 feet later, I think you're better off sliding another 100 feet with the gear intact.
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.

That would be my choice too ... gear up .... nothing to dig into the ground to cause a flip ..... there may even be some residual ground effect between the wing , corn , and earth during the last few inches of descent which could help smooth things out.

And like you said , gear would remain undamaged if aircraft is going to be rebuilt.

Now I am going to contradict myself .... main gear needed to be redesigned anyway .... it was troublesome to watch his wheels flex fore and aft during tests on a smooth runway .... that movement would be absorbed at the hinge-pin embedded in the fuselage where he had glued the mount into the carbon spar . Dangerous design. He already had to "re-glue" the mount when the bearing popped out of place.

.
 
Is it just me, or is this whole thing a bit similar to the thread about the guy with the float plane that crashed it six times in a week? It's like watching a traffic accident in very slow motion. Or a Road Runner/Coyote episode in a serial installment version, less the "Acme" labels. Maybe I'm being too harsh, it's Monday.
 
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