Now, you get me worrying even more! Because my wings are plain fiberglass
skin! Mind you, this is seriously thick fiberglass, so no wonder the plane
has survived for 400 flight hours ; - )
I believe these wing skins were sold in South Africa by the RR
representative back in the 1980's. The manufacturer was (still is?) a
respected composite expert with a lot of interest and experience in
gliders. The skin is made of two halves that are positioned over half a
dozen light foam ribs, plus a solid expanded polystyrene leading edge foam
block. Needless to say the leading edge is rock solid.
Well, at least, you just gave me a good justification for those new ribs I
am building, whichh I so far considered a serious overkill.
Serge Vidal
KR2 "Kilimanjaro Cloud"
Paris, France
"Mark Langford" <n5...@hiwaay.net>
Envoyé par : krnet-boun...@mylist.net
29/05/2006 00:53
Veuillez répondre à KRnet
Remis le : 29/05/2006 00:53
Pour : "KRnet" <kr...@mylist.net>
cc : (ccc : Serge VIDAL/DNSA/SAGEM)
Objet : Re: Réf. : Re: Re: KR> removing the foam after glassing as wing.
Serge Vidal wrote:
> Makes me wonder... for those of us who have molded wing skins, Dan Diehl
> style, how much weaker would our KR2s be as compared to the original
Rand
> Robinson foam core design, and what would the failure mode be? High Gs?
> Nearing the VNE?
Diehl skins have a quarter inch foam core (I think it is), but since it's
glassed on both sides, rather than just one side, I'd call it much
stronger
and stiffer. The two sides are even joined with "risers" of resin created
by something akin to a bunch of nail holes in the foam before vacuum
bagging. Mine are built with glass on both sides as well, and I think
they're pretty tough wings. Don Reid has done an analysis on the wing,
and
determined that the spars will fail first, where the bolts hold the wing
attach fittings on. I don't know of anybody that's had either the skin
or
the spars fail during flight, however, so it may not be worth worrying
over...
Mark Langford, Harvest, AL
see homebuilt airplane at http://www.N56ML.com
email to N56ML "at" hiwaay.net
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