What is a lightweight material that is sturdy enough to hold up a good bit of weight?

Okay well I have quite a bit of sculpture experience and I will tell you now, something that is both strong and light will probably end up expensive, it's just how it goes. For the body, paper mache works okay, you'd be surprised how much of a beating it can take if you have a chicken wire structure that it's done on (and it doesn't get too heavy). Wooden dowels are fairly light, but those bend really easily, so your wings will probably droop under their own weight. You might have to compromise with something heavier then, like thin metal rods. Cardboard, although it sounds ridiculous, is actually really good for structure if you get it thick enough (just glue sheets together). Fabric is heavy, so if you plan on wrapping your wings in that go for very light fabrics and use as little as possible. Paper mache for things like feathers works great too, I've done a few bird costumes with that. Plaster is crumbly, so I wouldn't use that, but there are other things like silicone (expensive) or plaster cloth over chicken wire (cheap). Hope that helped a bit. G

Eleven feet of almost anything is going to be a problem. Mounting 5.5 feet of anything is going to be even more of a problem. You might start a weight lifting program :-) But I suspect you will only get the weight strength balance you need by going to a triangulated steel wire structure covered by the lightest of fabrics and pivot it off of a frame of stiff wire that the hollow body is built off of and around. You may find that getting it welded/brazed is the best option although using bent ends, covered in epoxy and wrapped may give you a strong enough cold joint. The only alternative I would consider would be to use the techniques of wood and fabric flying model airplanes where the fairly firm light spars of wood are put in compression by the thin fabric that is doped (painted) and shrinks into tension. And you may have to find an "old" RC airplane builder to help because I don't know if people still work that way or are all using shaped foam. I fear that any method involving wood, ordinary fabrics to contain quilt stuffing is going to end up far too heavy for mounts in wood and for carrying.

Eleven feet of almost anything is going to be a problem. Mounting 5.5 feet of anything is going to be even more of a problem. You might start a weight lifting program :-) But I suspect you will only get the weight strength balance you need by going to a triangulated steel wire structure covered by the lightest of fabrics and pivot it off of a frame of stiff wire that the hollow body is built off of and around. You may find that getting it welded/brazed is the best option although using bent ends, covered in epoxy and wrapped may give you a strong enough cold joint. The only alternative I would consider would be to use the techniques of wood and fabric flying model airplanes where the fairly firm light spars of wood are put in compression by the thin fabric that is doped (painted) and shrinks into tension. And you may have to find an "old" RC airplane builder to help because I don't know if people still work that way or are all using shaped foam. I fear that any method involving wood, ordinary fabrics to contain quilt stuffing is going to end up far too heavy for mounts in wood and for carrying.