ajcoholic

My Feedback: (10)

I am designing a new fun fly plane (46 to 53 size) that is going to have a 48" wingspan one piece wing made from white foam. Chord is 12" without the ailerons and its a fully symetric section.

My question: I am aiming for a CHEAP plane that will be built in numbers for me and my buddies to bang around (low hovering, tail dragging, maybe some combat too!) and do not want to spend too much time or money covering the wing.

I was thinking of using brown kraft paper and west sytems epoxy resin to cover the wing. Any one do this before and how was the result?

I am also open to other ideas, besides light weight FG as that is an option but I want to use just one coat of resin (no filling cloth weave, extra weight!) and then dress it up with some vinyl decals. Keeping it light..

Thanks,
Andrew Coholic

Ollie

Put a very light coat of water based contact adhesive on the foam. Let it dry thoroughly. Apply a stripe of glass reinforced packing tape at the thick part of the wing, top and bottom, tip to tip. Do not tension the tape against the foam or it will warp. Then cover the wing with thin mylar packing tape. It comes in colors besides clear and brown. This is the way slope combat wings are done. You could consider using EPP foam instead of styrofoam for the wing cores for extra survivability. If you use EPP foam, you can use 3M77 contact adhesive instead of the water based stuff for good weight saving. Nothing will be quicker, lighter, cheaper or more survivable. EPP foam come in 0.9 pound per cubic foot density and also 1.9 pound per cubic foot density. It cuts at a higher temperature than styrofoam.

ajcoholic

My Feedback: (10)

Ollie,
Thanks for that tip! The fellow that is cutting my cores is looking into getting some epp foam as he has had requests for it from the glider guys.

One thing, if the wing is covered in the packing tape (which by the way I use often as a release for epoxy work) how do you glue something to it? I guess you would have to cut the tape away and epoxy right to the foam.

Keeping this plane light is as important to me as keeping it cheap.

I have a lot of 3 mil sign making vinyl (offcuts and such from a local sign maker) in many colors, and the stuff isnt much thicker than the tape. Think that it would be OK instead of the tape?

Thanks!
Andrew

Ollie

Contact cement works to attach something to the shiney side of the tape. I wouldn't depend on any such joint for structural integrity. Use vinyl tape (such as book tape) hinges for the control surfaces. Put the hinge line at the surface rather than centered. I would cover the EPP after all the structure is complete. Shoe Goo or Goop also sticks to almost anything. It is useful for gluing EPP parts together.

The EPP foam isn't as stiff as styrofoam and it needs stiffening by covering with mylar packing tape. Three mil vinyl tape isn't as stiff and weighs a lot more than packing tape.