homebuilt safety

"anonymous coward" wrote in message
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But that's not a feature of the basic airframe design, which is the
subject
that we're addressing here.
Does it really matter?

I guess it's pertinent; it's all about risk mitigation. But pilot protection
(beyond accident prevention) starts with the airframe design. Having a
crushable foam seat bottom won't matter much if you end up with the engine
in your lap.

protect against would be loads on the spine if you hit the ground
horizontally and with a high rate of descent. Incidentally (and as you can

Yes, but a hard landing might be the most important design point. How many
ground loops begin with a pilot landing hard and losing control?

guessing you would need quite soft foam, otherwise it wouldn't deform

The foams they use for helmets are pretty hard. They won't deform until you
hit a threshhold. You don't want something that will compress under normal
loads.

Another idea was putting a big chunk of foam at the front of the aircraft
to slow the deacceleration if you hit something frontways. Say you have to

We could be talking about a lot of energy. Might require a lot of foam.

airframe may break. Perhaps a cubic foot of harder, crushable foam in the
nosecone could reduce peak loads on the airframe and spread them more

Where in the nose would you put it? I was thinking of maybe something behind
the instrument panel, maybe attached to the firewall. Speaking of fire....I
think I have an old bicycle helmet laying around. Maybe I'll put a match to
it. Anyway, I'm sure there's data available on foams currently in use.

I'd be interested to hear more about these gliders' reinforced cockpits.
Perhaps all this speculation has been despeculated already?

Perhaps. I would think that you'd have an easier time with composites in
building a really stout shell around the pilot. Just a couple more plys of
glass/carbon/kevlar/whatever..... It could give more protection than a metal
design. Composites seem to be easier to design with for energy-dissipation.
You can't tear them easily. The tubs that F-1 drivers sit in are all
carbon, with the outer structure designed to shred nicely if the car hits a
wall at high speed. I have a friend who used to work for Dan Gurney in
Anaheim, and he gave me an insiders tour. He showed me the chassis that they
had slammed. The inside of the tub looked new, but everything outside it
was just shredded. Airplanes don't give anywhere near that level of
protection.