Postby BWD » Thu Oct 13, 2016 6:16 pm
yes you can copy wings without breaking any laws.
It is not wrong to do so, and general wing designs can't really be patented, most basic airfoils are developed from open source data, many from government funded research.
Many others are also public domain, shared by their creators.
in practice, each wing version built comes out how it does anyway, and all builders tweak, scale or adapt shapes to fit their needs or technology.
What can be and sometimes is protected is the "design"as in appearance, logos, etc., via trademark.
So not really a concern in my opinion.
Tungsten's method -vacuum forming flimsy PET sheet molds- may work for a 4" 25cm^2 fin. At that scale, they are actually strong enough.
Would it work for a 8" 10cm^2+ fin? Not as well. For a 500-600+ cm^2 wing half? Not well at all.
Molds must be rigid to reproduce a shape correctly.
You could vacuum plastic film, a few mil, to a wing instead of waxing the wing, and then lay up a fiberglass mold over it. That way you would not worry that your mold would permanently stick to your friend's wing. Plenty of layers, starting with filler and light cloth, then thicker cloth, backed with a mother mold or big reinforcements. Like how they mold fiberglass boats, but simpler and miniature. You might want/need a mother mold to carry the mold, too. This process might give 1-20 faithful copies pulled from your mold before distorting or wear and tear gave issues. Your mileage may vary. But it is do-able, and probably done often.