Hmmm - don't know why I didn't reply to this when it first showed up.

Glass - good all around use. Cheapest option. E-glass is standard, S-glass is lighter for a given strength.

Kevlar - Impact resistance par supreme.

Carbon - highest rigidity, lowest weight. Can be brittle. Most expensive.

I'm a big believer in using a combination of fabrics to take advantage of their strengths and cover their weaknesses. All have advantages and disadvantages.

Rolling tubes is probably the most difficult and expensive thing to do at home. Proper mandrels are machined from aluminum and highly polished. For smaller tubes you can get away with paper or phenolic coupler material covered with mylar and wax. For larger, metal rules. If you're vacuum bagging, only metal can be used without going through a rigamarole to prevent the vacuum from collapsing the tube.

Warren

People don't use much kevlar for a few reasons:

1) It's very difficult to cut.
2) It soaks up epoxy like it's going out of style
3) It tends to end up very heavy for a given quantity of fabric (this is related to point 2)
4) It's fairly expensive, and significantly weaker than carbon in most ways.

It's true that it's slightly better in impact resistance than carbon (although carbon's brittleness is often exaggerated), but there are only a few scenarios in which you want impact strength rather than stiffness and absolute strength.

As for hybrid fabrics? They're mostly cosmetic.

So for those of you that have experience with these things, isn't a good glass tube sufficient for just about anything we do? I realize carbon is stronger for a given weight, but I have to add weight to get to optimal mass in every single rocket I've built, and I'm not being overly delicate with the builds either. I currently own 3 all glass rockets and have glassed tubes (cardboard or phenolic) myself on 3 others, and I really can't beieve that any of them suffer for not being carbon. Carbon certainly has the sex appeal aspect, and a goal of mine is to build a rocket with a clear coated or polished carbon weave finish, but again, that's just for looks. I would expect that a most basic composite construction done properly, ex. cardboard tube with 2-3 layers of med weight glass cloth, would stand up to virtually anything.

So how much of our material selection is based on need rather than "cool factor" for lack of a better term?

Oh it is definitely the cool factor. Over-building has always been my path in most everything I do - remodeling, automotive, rockets, etc. If you check out Tony's post on the Kestrel, you'll see what needs to be done. I tend to go much farther, but then on most birds I'm trying to build something durable and not squeek every inch out. There are exceptions mind you...

Warren