ORIGINAL: rg1911
Matt,
That certainly is a wealth of information!
I have the .3-ounce veil. I didn't do enough research to learn that the light veil is used for stiffness, not strength or ding resistance. It also sounds as though I should get nitrate dope to apply the veil before filling it with the urethane. Or possibly hitting it with a high-bulk sandable primer as filler and finishing with the urethane.
Your other idea, to use it *under* the skin for stiffness, is a real possibility. (Although it sounds as though I'd need to let the nitrate or epoxy cure with the sheeting tacked and formed to plastic wrap-covered ribs.) That would impart the stiffness with, I would hope, little added weight, and then use glass on the top surface.
I had planned to use carbon rods glued into the rib alignment holes until I weighed the 5/16 rod. It came to 3.2 ounces and there would be two for each wing panel, or real close to a pound of weight.
Or I may be seriously over-engineering this build.
Again, many thanks for your time and detailed information.
Cheers,
Richard
Hmmmm....3.2 ozs for a carbon rod seems heavy to me. Carbon tubing, thin walled should weigh no more than about 15-20 grams per piece. With the large panels planned (I think they are around 50" each, right?) you should use some form of spars in the built up wing. For even better strength you might consider forgoing the carbon install in the alignment holes and relocate the carbon tubes into the spar holes in place of the wood spars. Lighter and stronger and stiffer. Just an idea.
Total weight shouldn't be, what, 10 lbs? I mean for the whole plane, how much weight does the wing really need to support?
My foam wings are generally skinned with 1/32" or taper sanded 1/16" contest grade, with carbon veil inside. Each panel has a span of 37" in a typical example, and an area between 500 and 550 squares. Full skins weigh 40 grams each, top and bottom. The panels are joined with a joiner tube, usually carbon thin walled 7/8" x 040. It's a different arrangement for certain and is without retracts. Actually, with a socket installed, the wing design would be adequately strong for retracts too but that's not in my plans right now. The outside is either carbon veiled or silkspanned. Power is typically 4 HP, 30-35cc gas engines on pipe.
I am so confident of their strength that for my new plane design the same wing design will fly using a 6 HP 55 cc engine. Total flying weight will be around 12 lbs. Just a couple numbers to gauge by. Good luck with your builds and if I can assist in some way, don't hesitate to contact me