Composites and epoxy, was Re: Coilovers $195 for all A1's

[rocco16v at netzero.net (L F)]

(To those few individuals who may be inclined to interprete this incorrectly, please read the following in a calm, non-confrontational manner as this is how it was written)
Dan,
  While what you say is 100% accurate, it also supports my position in that composite F135 (JSF) wing skins are not structural and rotor blades are a gray area....composites are not joints. (the issue being discussed is using epoxy to JOIN components, not MAKE them)
The company I work for makes stressed body skins for this aircraft and the F22 and ALL the stressed outer surfaces are titanium.  The unstressed (non-structural) skins are composite.
I'll stand by my earlier statement that major load-bearing components in modern fighter aircraft are not joined by epoxy.  There is just not enough history on epoxies to risk their use in this fashion.   You would be amazed at the long-term (l-o-n-g term...) testing ANY material and any process has to endure to be accepted in the world of aerospace.  That's one reason there are $400 toilet seats on aircraft.(not the ONLY reason, but one...)

I'll ask the Boeing and the Lockheed-Martin engineers at work tomorrow.  Maybe there is an isolated case on an older aircraft, who knows....
(guarantee they weren't doing it in WWII....all we had then was glue made from animal by-products!) 

Larry
(sorry, but I couldn't fit all the above into one sentence)
  ----- Original Message ----- 
  From: Dan Bubb 
  To: L F ; scirocco-l@scirocco.org 
  Sent: Monday, January 26, 2004 4:38 AM
  Subject: Composites and epoxy, was Re: Coilovers $195 for all A1's


  Riveting and bonding/gluing has been a common construction in aircraft for over 30 years. Bonding by
  itself without riveting? I kind of doubt this. Bonded epoxy joints have good shear strength, but
  poor peal strength, so you typically need mechanical assistance to prevent pealing.

  As far as composite use in aircraft it is most definitely not confined to non-structual
  applications.
  Examples are the one piece wing skins on the Joint Stike Fighter.
  Harzell's composite blade propeller that has an "unlimited service life designation from the FAA."
  F-22 Raptor is 24% composite construction BY WEIGHT! including use in the fuselage frame and for
  wing spars.

  Dan