I believe that the plywood ribs act as the template so to speak of the finished wing profile facilitating the final sanding of the foam and spar caps. I used inexpensive 1/8 exterior plywood, cutting larger lightning holes to keep it light then gluing on one inch foam to that using epoxy to provide some safety margin and strenght in compression. I then epoxy coated the outside face. Most wood aircraft have compression members between the spars, so, just in case!!!! I suppose foam glassed on both side might be similar in compression. Extruded polystyrene, the blue, gray or pink stuff that is common in household construction? I built my whole plane with that stuff except for the fuel tanks. I did glass both sides of the polysytrene ribs on the outer wings but using plywood for the end ribs. ----- Original Message ----- From: "Serge VIDAL" <serge.vi...@sagem.com> To: <kr...@mylist.net> Sent: Wednesday, December 29, 2004 7:24 AM Subject: KR> Ribs
> I am still busy with the rebuilding of my WAFs, and I am hesitating > between making plywood ribs, or foam ribs. > > After having checked the plans, I get the feeling that the plywood ribs > are in fact there just in order to hold the foam during wing construction, > and little else. So, it seems that I can do whatever suits me best. Am I > right in assuming that? > > Questions: > > - If I go for plywood ribs, which thikness plywood should I use? > - What should I coat the plywood with? > - If I go for foam ribs, can I use high density extruded polystyrene foam? > > > Serge Vidal > KR2 ZS-WEC > (redoing the WAFs) > Paris, France > > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html
