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Old Jan 17, 2013, 07:11 PM
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608 km/h!
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Australia, QLD, Toowoomba
Joined Jan 2010
3,974 Posts
Hey Ace, I was told not to re-invent the wheel when I started building planes, I think this was some sage advice. If you are going for moulded, which is really the only way, if you want the detail imprinted into the wing, you need to bag it to get what you want. Use balsa as a sandwich medium and carbon is definitely not necessary for the skins, but uni carbon or tow is needed for the spar caps- dont worry, its pretty cheap. The reason you need to bag is because to make a light hollow moulded skin it needs a core and I cant see how you could do this with out bagging it, especially if your tips have compound curves. Also when bagging a lot of excess resin/ weight is sucked out of the layup- so you end upwith a much lighter and stronger skin. A good layup for cheap/lightish/strong is, from the outside in, 4 or 6oz glass/ 1.5mm balsa/ 2oz glass. Some will say this is too heavy, maybe it is, but I have forund it a good compromise between stiffness, dent resistance and light weight. Also, bagging equipment doesn't have to be expensive, get hold of an old fridge pump and some PVC drain pipe and you can start from there. There are many threads on how to build your vacuum set up.
Another advantage you will have with a PSS scaley is that the wing will have a pretty fat section, giving you lots of stiffness- Us glider guys have to put lots of carbon into the spar trying to make really thin arifoils stiff enough!
Good luck with it mate!
Josh
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