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ACRO E-mail Archive Thread: [IAC] Accidents


Thread: [IAC] Accidents

Message: Re: [IAC] Accidents

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From: Coderman at

Date: Fri, 16 Jul 1999 11:58:41 UTC


  Previous posts have covered some basic physics and design differences between 
formula cars and aerobatic a/c. IMHO there are at least two nother 
significant survivabillty factors that may be addressable with aerobatic a/c. 
One is cockpit airframe strength, the second is fuel tank/engine proximity.

While it is impractical "weight-wise" to surround the pilot with a steel roll 
cage there appear to be some practical tradeoffs here. Contrast the 
PItts/Eagle/Extra with the Super Decathalon airframe and you see the benefits 
of a "caged" cockpit. In the Super D, you do not have nearly the visiblity of 
a bubble canopy, but neither to you have the exposure. Also, the fuel tanks 
are in the wings of the Super D, whereas the fuel tank is just ahead of the 
cockpit in most of the "high performance" aerobatic a/c. I've seen pictures 
of a Super D totally mangled where an aerobatically inexperienced pilot 
attempted a "slow roll" immediately after takeoff and ended up in the weeds. 
The pilot didn't walk away, but survived with substantial injuries only due 
to the strength of the Super D airframe.

A bubble canopy is neat, provides a great view, but provides virtually no 
impact protection. Seems that since this is about the same difference as a 
"convertible" vs. "sedan" in the automotive world, that an inverted U of 4130 
welded to the airframe just aft the seat(s) in bubble canopy models would 
provide at least a measure of protection more against fatal accidents that 
involve flip overs or inverted ground contact. Other than that, there seem to 
be some major engineering challenges here.

Bill Kaercher
Venice, FL


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