hardware store window insulation heat film

You could buy a bunch of space blankets and use packing tape to hold them together. Probably the cheapest source of mylar available and it is nice and shiny.

Originally Posted by CAFplanekid

I can't remember the name of the plane, but there is a manned, powered plane that has been around a while made out of pink insulation foam. Search for it.

That is a huge piece of foam! Ribs could be made of regular 2" insulation foam for less cost and easier cutting. Cap the ribs with yard sticks.

PVC is pretty flexy: you might be able to find bamboo at a landscaping store.

The best craft at the event I was at was built like a huge kite, by a company specializing in fabric and aluminum tube sculptures. It had a surprising glide ratio, thanks to a huge wing area. I have not really seen any conventional air foil designs do well. You just can't get enough airspeed, and alot of the time the wings buckle as soon as they go off the edge and fall.

1x3 OR 1x4 laid flat with1/4 ply between for a very nice spar. Route a 1/4 groove for the ply to be glued into.

I think I would go with some heavy plastic drop cloth for the covering.

aircraftspruce website sells aircraft dacron. About 17 cents a square foot, in 60 inch rolls.

Glue it onto wing spars with white glue. When glue is dry, use a hair dryer to shrink it tight.

This is what the big scale RC plane builders use. It must be sealed with something like Polycritic clear floor finish, or a light spray paint job.