In a message dated 3/31/2004 4:17:18 PM Central Standard Time,
mjrav@comcast.net writes:
I'm not sure of your point.
In the cases you describe, the graphite is designed to cary the whole
load and the glass is only the supporting structure. That's good
engineering. The L2 spar and legacy skin are perfect examples. The
carbon sections are thick and strong enough to carry the whole load.
(Webs of beams, ribs and bulkheads only support the load bearing
parts).
If you were to make a spar cap by substituting glass for half the
graphite, you would have precisely the two rope scenario and 25% less ultimate
strength.
Mr. Speed Demon Ravinski (emphasis on the Demon),
1. I am frequently referred to as pointless.
2. Point: Only that there is no problem with the bonding of carbon to
glass.
3. I do not believe that the carbon is designed to carry the whole
load. However, as we approach destructive distortional discombobulation
(technical term), the carbon may shatter before the glass. Technical note: See
my carbon tennis racquet's disquieting destruction after accidentally contacting
the net post! Technical comment: Bummer.
4. Monocoque construction only says that the enclosure participates in the
structural strength - It is not the sole athletic supporter. Such
construction makes no reference to a thing defined aviationally as "wing". Like,
who needs a spar?
5. One may design for terminal collapse at ultimate strength but, as a
practical matter, one operates within the 50% of that boundary of ultimate
discombobulation - thus taking advantage of the budgeted give to carry the
everyday load. Note: I do not like the word "terminal."
5.a. Aluminum bends, composites break! (Uh, I ran out of paper for
further illumination.)
6. See 7
7. I cannot understand any "rope" analogy without the mental imagery
of hearing a reedy wailing flute influencing the stiffness of a vertical rope
emerging from a wicker basket to be later climbed by a wizened turbaned
wizard.
Scott Krueger
AKA Grayhawk
Sky2high@aol.com
II-P N92EX IO320 Aurora, IL
(KARR)
LML, where ideas collide and you
decide!