I don't jump into very many discussions anymore, but, I just can't resist when the answers are already well known and a little study will reveal them.
OK, there is no need to reinvent the wheel. Rutan has already done that for you. The book "Moldless Composite Sandwich Homebuilt Aircraft Construction" is the definative work on using fiberglass/foam structures in aircraft construction. If you are still debating how to use foam and glass, get the book. Stephen, one of the points you are missing is that the styrofoam we use for model airplane wings is CLOSED cell while the foam used for full scale aircraft construction is OPEN cell. This is why you don't need to micro model wings and you do full scale wings. Read the book, it explains everything. Better yet, watch the video. Both can be ordered from Wicks. Steve Eberhart http://www.newtech.com/nlf/ 91 MIN 21-35830 24.95 BUILDING RUTAN COMPOSITES A step-by-step program featuring Burt Rutan showing the complete process for utilizing his fiberglass-epoxy-foam construction 91 min. VHS BURT RUTAN CB 14.50 COMPOSITE BOOKLET The book "Moldless Composite Sandwich Homebuilt Aircraft Construction" consists of 26, 11 x 17 pages (equal to 52 pages) describing how the material is applied, education on the materials, tools required, inspection and repair methods. Written by Rutan Aircraft Factory. This book is included in the practice kit number CK. Stephen Jacobs wrote: > If you put fiberglass over foam without first squeegeeing in SOMETHING, > the fiberglass will not stay attached to the foam for long... > > ++++++++++++++++++++++++++++ > > With respect - I am not convinced the above is correct when it comes to > polystyrene (Styrofoam?). > > This is something I have been trying to understand for months now - what > are the salient differences between styrofoam and polyurethane foam in > terms of their respective characteristics - strength in shear and > surface competence (for adhesion of a skin). > > Take some duct tape and try to stick it to a sheet of poly-u. The tape > will readily come off (fall off) with a thin layer of urethane "dust" > coating the adhesive of the tape. I have no difficulty understanding > that polyurethane needs something to "bind" and seal the surface in > order to achieve any degree of competent surface (suitable for attaching > a skin). > > The same tape attached to a sheet of Styrofoam will take much more > effort to remove and will actually tear out individual beads - it has a > substantially more competent surface (for sticking things to) - will a > slurry mix benefit this in any way? > > I have built model airplanes up to 40lb (some are now 25 years old) with > a variety of wing skins (balsa wood, veneer, glass cloth) attached to > styrofoam directly with epoxy. As any modeller will know, these birds > are subjected to G loads many times higher than real airplanes - I have > never had a failure in the skin attachment. Before I could afford epoxy > (1972) I sealed the Styrofoam with a coat of watered down PVC white > (wood) glue and used general purpose polyester resin and glass cloth. > Very often these wings had no spars so the skin-to-foam bond was > critical. > > Dene (from Gods own country) - your buddy that produces the brilliant > Whisper motor glider makes extensive use of white Styrofoam for the > wings - maybe ask him what he thinks /recommends !! > > As I said - with respect. > > Steve J > > > > _______________________________________ > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html >
