? Pete and all, obviously many have used this type of foam over the years . It provides as a filler to form a shape just as does the rigid urethanes most have used for their wings. Yes urethanes sand fast and easy but again it too is easily delaminated as many have found out over the years. The klegicell foams are a many times superior foam for aircraft structures and was not available when Ken Rand designed the KR aircraft. He used what was available but now that we know of superior products why wouldn't we use them? I wish I could talk everyone in this group into purchasing one piece of klegicell type foam, do a one or two ply layer of bid on a 12" X 12" piece then do the same on the Home Depot blue or pink and the same on the green or tan urethane. Let them all cure for a day then get a hold of?a corner and see if you can take the cured cloth off. The pink and blue will immediately delaminate and come off? easily as it will the green or tan urethane. You will not be able to take it off of the klegicell it is a tough more structural type foam. It is the same type of foam Dan Diehl used in his pre molded wing skins. Just try this, it will make you cry if your serious about long term airframes, especially wing skins. My friend that found the aluminum WAFs in his KR wings found them because his wing skins had delaminated from the green or tan urethane foam his wings had been built from. I didn't see it, he told me about it. The Varieze? fuselage floor sidewalls and nose were made from the green urethane 2" thick foam sanded to shape with four spruce longerons? one in each of the four corners?lengthwise in the fuselage?like a KR and it has a aircraft grade?plywood firewall and?bulkhead which was the instrument panel but no other sticks Inbetween like a KR. The wings on Ezes are Dow styrofoam not expanded polystyrene. This type of Polystyrene is what white cheap ice chests are made from as is the same type in?sheets used in packaging for shipping,??most people call that styrofoam but its not.? Dow Styrofoam is much stronger and is what solid core wings are made of in?Rutan?canard?types of airplanes. It is easily hot wired to shape. The Longeze uses the klegicell foam for all structure floor?sidewalls seat backs, instrument panel, fuel cells?and the canard attach structure with certain numbers of layers of bid or uni on all of course. The solid core wings and winglets are made from Dow Styrofoam. I believe it is a extruded product but came in 8 or 10" thick billets. it has a tough outer skin on it when in this form. it used to be sold in 7 or 8" thick by 10 or 12" wide sawed out pieces without the extruded skins on them.
Pete you are probably fine for your canopy frame, most Eze canopy frames were made using the green or tan urethane because it sands easily. Rutan's designs relied upon a carefully designed layup schedule? of unidirectional and bidirectional cloths for strength but he switched to klegicell foams as soon as he found out about it over 30 years ago now!!!! Wow I'm getting old! If my memory serves me I believe klegicell was developed and manufactured in Sweden originally. On canopy attach points like latches?you need to remove a small area of the foam, replace it with hard points made from high density klegicell, wood, or hard blocks made from multiple layers of bid cloth. All of these need to get floxed in place then glassed over by overlapping the surrounding already glassed area by at least one inch on all sides to form a structural connection. The ideal thing is to flox these hard points into the shaped foam before it is glassed in the beginning. I don't think anyone is going to die but obviously if you were to have a high speed air penetration/delamination under a wing skin for example one could be in serious trouble quickly. We will pray that never happens. Hope this helps Larry Howell Pete Klapp <pkengr at hotmail.com> wrote: > Larry > I did use some of the pink foam when constructing my canopy frame. While it > is not a structural component such as a control surface, do you think this > will be a problem? There are three to four layers of kr glass covering the > foam to create a box beam like member that the canopy was then glued to with > flox. Should I consider building a new frame or wait and watch to see if > there will be an issue? > Pete Klapp > >>
