Carbon Fiber? Does it work?

[rocketgirl<3]

Hey guys,

I just recently got hooked on model rocketry. I don't know that much about it, but I'm a quick learner. Recently, I purchased a heat gun from the local hardware store and started messing around with composites. I also bought some carbon fiber wrap (pretty expensive stuff) and tried using it for a coating on the outside of my rocket with epoxy. Would anyone recommend carbon fiber? I'm afraid that the intense heat near the nozzle with create some sort of disfiguring process resulting in a fire or something worse.

Thanks!!!

 

[ben_ullman]

I would never worry about a motor (case) setting a rocket on fire. Carbon Fiber is great for strength but it also is alo a little brittle.

What size rocket are we talking. Anything not built for speed or needing strength in the 54mm on up group doesn't need CF. (IMO)

Ben

 

[troj]

Carbon Fiber is great stuff, and has a myriad variety of uses.

That said, I think it gets way overused in this hobby. It doesn't hurt anything when that happens, other than your finances, as it has gotten to be hideously expensive. It does have a cool factor, though....

To give you an idea, last year at LDRS, we flew a rocket on a Q motor that had absolutely no structural composites. We didn't use any carbon fiber, and the only fiberglass used was a light layer over the foam nosecone skin -- the fiberglass was thin enough you could punch through it with a fist, if you wanted to.

What types of rockets are you building that you're using carbon fiber on?

-Kevin

 

[JDcluster]

To gain any real strength you need a 1-3 layers with the correct ratio of epoxy.
One down side is; that it doesn't sand well at all & needs a sanding veil such as fiberglass cloth.... CF needles can be a real pain as well.


JD

 

[powderburner]

rocketgirl,

If you are building a kit, you will almost always be just fine to use the parts and supplies included in the kit without much chance of having problems in flight. You would have to go waaaaaaay past the recommended motors (for that particular kit) before you would begin to have airframe problems.

And when it is time to reinforce, there are other intermediate (and less expensive) steps. You can over-wrap with another piece of airframe tube, or insert a full-length piece of coupler material. You can add lengthwise strips of spruce (like, lined up with the fins) or some other stiff structural material. You can switch to a different body tube material, one that is stronger.

When you get to the point where an outer laminate is necessary, fiberglass is much less expensive than graphite, and will still provide a significant structural benefit. Fiberglass can be added as a woven fabric that wraps all around the body tube, or (a lighter approach) can be added in the form of uni-directional fibers epoxied onto the length of the body tube.

One thing to avoid: you will see some folks use nylon--as in women's nylon stockings--to laminate onto the outside of a body tube with epoxy. They may try to tell you this is good. Do not listen. Do not laminate with nylon. Nylon adds absolutely no structural reinforcement, and the layer of epoxy/nylon adds unnecessary weight.

Graphite fiber can look cool, but it is really only necessary for the most demanding applications. In the mean time, working with graphite fiber composite material has certain hazards. When you cut or sand it, it is unhealthy to breathe the stuff. And if the fibers float around in the air and find their way into your electronics (individual graphite fibers will behave like dust) they can get pulled onto a circuit board by static electric charges and cause a lot of damage. I would recommend that you stay away from graphite structural materials as long as you can.

 

[Sailorbill]

Hey guys,

I just recently got hooked on model rocketry. I don't know that much about it, but I'm a quick learner. Recently, I purchased a heat gun from the local hardware store and started messing around with composites. I also bought some carbon fiber wrap (pretty expensive stuff) and tried using it for a coating on the outside of my rocket with epoxy. Would anyone recommend carbon fiber? I'm afraid that the intense heat near the nozzle with create some sort of disfiguring process resulting in a fire or something worse.

Thanks!!!

rocketgirl<3
Depending on where your interests in composites lie you could join the Yahoo Composite Rockets Group. There are several tutorials etc.
Oh and welcome to the hobby and TRF. A couple of other forums you can checkout are Rocketry On Line forums and Rocketry Planet forums. Many rocket people, myself included visit multiple forums. Each forum has a different flavor and style, lurk awhile and decide if you like it or not.

 

[Pippen]

Welcome to TRF, rocketgirl! Glad to have you on board.

 

[Zack Lau]

Carbon fiber is great when you need a perfectly straight thin rod or tube--such a support shaft in a Helicopter rocket that supports the blades high above the engine mount. Wood isn't cheap if you count the effort needed to find a dowel that isn't warped. But, this is a very specialized application--only a few folks in our club fly Helicopters.

 

[Mark_1984]

My two pence worth. You can achieve a similar strength from glass fibre and resin as you can from carbon fibre and resin. The principle difference being, carbon fibre gives you a lighter rocket and a lighter wallet !!

If you need strength without a weight penalty use CF. Competition use is a typical example that springs to mind. If a couple of extra ounces, and a rocket that doesn't go quite so high is fine, then CF is a waste of money.

Of course, if you're after looks, naked carbon fibre every time. It looks the dogs dangly bits