The primary function of the foam is to provide the shape for the structure, and to provide a small degree of structural and compression related strength. While wings certainly can be and have been created hollow with just the skins shear webs and spar caps, it generally requires greater manufacturing capability than the average homebuilder can provide. The most important factor to keep in mind with sandwich style construction is to keep the sandwich symmetrical in nature, with the same number and type of layers on each side of the foam, or stress transferrence can lead to structural failure of the thicker layers, as they will be carrying the majority of the load instead of it being evenly distributed throughout the sandwich. The type of foam is pretty much a personal choice and compromise between compression strength, weight, and foam qualities. Just bear in mind, as has been already pointed out, that fuel will dissolve styrofoam, so if you are putting tanks anywhere near this stuff, you better make darned sure it is well sealed and isolated from potential leaks. Cheers. Peter Bancks. stranged...@dodo.com.au http://www.homebuiltairplanes.com http://canardaviationforum.dmt.net
--------- Original Message -------- From: "KRnet" <kr...@mylist.net> To: "kr...@mylist.net" <kr...@mylist.net> Subject: RE: KR> Foam vs. Foam List-Post: krnet@list.krnet.org Date: 24/07/04 20:13 RE: I cannot see that polyU will outperform Styrofoam in compressive or tensile strength - maybe the shear capability is the issue? I question strength being an issue at all, when deciding on what foam to use I thought that is was just there to be shaped and covered with glass. Is this a wrong conclusion? "There is a time for building and a time for GOING TO THE GATHERING, and the time for building has long since expired." See you in Mt. Vernon - 2004 - KR Gathering http://KRGathering.org See N64KR at http://KR-Builder.org - Then click on the pics Daniel R. Heath - Columbia, SC
