You worry me when you say it is not good !!! who is zeke Smith
+++++++++++++++++++++++++++++ Hey Ron - As the man always says, your results may differ. I discussed my concerns with Eduardo (this took some time as he speaks Spanish and I speak English). He certainly is a bright guy and appears to have done his homework. Everything else he has done is near perfect, including anodizing his ali parts and making up his own legs and leg attachments, fuel tanks etc. One other South American (Leo, he speaks English) is doing similar things with a GP4, in this case the wing was originally designed for a ply skin, but Leo is doing a KR wing type skin, but staying with the original design spars. http://www.geocities.com/leoadrena/GP4.html Leo built a nice KR before, so he has been around DIY airplanes for a while. Zeke Smith has written various books and articles on composite structures - I see him as knowledgeable in these matters. If he perceives a problem with mixing E-glass and Carbon fibre in the same lay-up due to the differences in stiffness (as suggested in the extract I included) - I must wonder to what extent the same problem will be present in Eduardo's Structure - he is mixing ply with glass. For that matter, how wise is it for Leo to build the wing sub-structure (spars /ribs etc.) according to the plans and then completely change the wing skin from ply to mould-less composite (not even a true sandwich)? I don't know, but my hopes are that one of the netters has an informed opinion and will share it with us. My strong interest is with Eduardo's way - I suppose the question really is which is "stiffer", the spruce frame or the foam/glass composite. If the Composite component of Eduardo's airplane is stiffer and takes the initial load, all is well (if the glass bit is spec'd to do the job.) The spruce frame goes along for the ride. If the spruce frame is stiffer and loads up first - it may not be strong enough without the ply skin and fail. We both seem to like his approach, so let me know if you learn any more. Take care Steve J
