Seeking recommendations: Composite material

I hope somebody does have a website for you, because there are a lot of issues here. But I can pass on a few basics.

First, no polyester. Epoxy will give you a much stronger result. Second, the amount of carbon fiber you would use in a 1/10 scale model is quite small. Someone probably has a good source for you. It will produce a chassis that is several times stiffer, and a bit stronger, than any fiberglass you can get, including S-glass.

The chassis design is the place to start. Is it a shear-panel type, or maybe some type of "tub" (monocoque)? If so, my thoughts would lean towards a balsa core with unidirectional carbon fiber, with epoxy matrix. The balsa will be a good former and it will give you some extra panel stiffness, assuming you cover both sides of the panels. Woven carbon fiber would actually be harder to work with than unidirectional strands or roving on such a small scale.

I can't help you with designs, using words. This is a job for pictures. Good luck. You'll wind up doing some experimenting to get anything really good. It's worth it.

-- Ed Huntress

As I'm sure you know, all of the team cars and high dollar cars are built with carbon fiber. You would be making a big mistake to use anything else...

Ed has it right. Epoxy is a lot stronger than polyester, it has very little odor, and by mail is only a bit more expensive than fiberglass resin at the parts store. I bought a gallon and a half of (very slow) epoxy from

Kevlar is stronger than fiberglass, less expensive than carbon fiber, but doesn't sand well. In any event $35 for a yard of carbon fiber doesn't seem an insurmountable price to pay.

If you've never worked with fiberglass/Kevlar/carbon fiber, you may want to try something easy first. Even a simple shape like a cylinder can be a lot of work. I build high-power rockets and now know several ways to do it wrong..... :-(

Best -- Terry

I don't think I understand how you could use fiberglass composite where you cannot use a graphite composite. They come in the same forms -- fabric, rovings, pre-made flats, rods... It's the same technology, different material.

Talc is only a filler. It has no structural benefit.

I built a main spar for my "gutsy lady" glider. It's .375 x 1" x 84", made from graphite ribbon, spruce, and aircraft plywood, laminated with epoxy. It'll take a cantelevered load of 60lb at the free end, if it's not allowed to twist. It bends like a fishing rod, but doesn't break. Graphite is that strong.

LLoyd

Ed had lotsa good points . If you want the car to be strongest, and that guides your design more than being an exact scale copy of a real vehicle, then the loads from all the suspension and drive train must be considered. Careful design here can make a remarkably light and strong car. ERS

The OP needs to find a local club of RC carpet racers. My son was rookie of the year at our local club, which, being located in Austin TX, was populated by a large number of brilliant young engineers with a huge excess of money and time to invest in this activity.

This environment was very cool. The track is carpet coated with a sticky substance, so it is absolutely consistent and uniform every week. The tiniest advantage made a huge difference. In our case, I convinced my son to concentrate on set-up. We used Carroll Smith's Engineer to Win and Engineer in your Pocket to tweak our car, and he got quite good at it. I am very proud that he took this experience to heart and has started in the Mech Eng program at UTx, with a goal of being an automotive engineer.

We finally had to quit when the cost per week started to approach $100 - new tires and batteries every week were merely the starting point. Electronically managed motor dynamometers, battery conditioners, tire truing machines, programmable speed controllers, titanium suspension pieces, and the chassis of the week club were all standard. Some of our club members were nationally ranked, and were sponsored, but as always, "Speed costs money, how fast do you want to go?" Saving money is totally counter to every other motivation in racing, and is therefore wrong-headed and a waste of time.

The point of all this background is that the OP is ignoring all of this incredibly competitive knowledge in trying to make his own chassis from some new material. He doesn't yet understand how important stiffness is - far more than lightness, and he is trying to save a few bucks in a hobby where cost can't be the limiting factor if he wants to be competitive. And if he doesn't want to be competitive, he should use aluminum which is cheap, easily worked, and very strong.

Airplane builders use a foam core that is sandwiched by fiberglass. Very strong, very light.