Hi,

I am working with a college project which is trying to produce prototypes for a new remote controlled racing sport. The sport is just an excuse to have a technology demostration testbed, much like formula one. We are using advanced Unmanned Vehicle technology to drive the cars, and want the cars to be as autonomous as possible. Using sensors and remote control to race the cars for four to six hours.

What does this have to do with carbon fiber?

Well, the prototypes that we are working with are made from something called a tetrix robot kit. http://www.tetrixrobotics.com/
This stuff is Heavy and I wanted to try and make mine as light and strong as feasibliy possible. I have always had an intrest in composites, but never had a chance to really get to work with them. After looking at the costs involved, I think that building the parts ourselves will not be any more expensive than buying the tetrix kits, and I think they will be more durable.

I have no doubt that the body work of the cars will be fine as either pure carbon or carbon-kevlar mixes, but I wonder if I will need to use coring material for the chassis, as these cars are being designed to drudge along at 70 MPH \ 112 KPH. Being autonomous, they will crash, and being remotely controlled, they will be badly driven, then crash.

My basic questions are this,

1.) Just how difficult is it to work with coring material?
2.) Is there a place that explains how to take your coring material and fiber and make a finished piece?
3.) Are cored panels really only ment to be straight, or can you mold them at all?
4.) Is carbon strong enough to handle being a Chassis by itself? Could I skip coring altogeather?
4.) and of course, do you guys think i'm barking up the wrong tree by using carbon fiber? (still interested for other projects, motorcycle repair yada yada.)

Thanks,
James

Interesting stuff!

I don't think i'm qualified enough to comment though. What you have to remember about composites is that they can only be made really strong AND really, really light if you know where all the loads would be coming from. If you are expecting a lot of impacts then, yeah cf / kevlar / diolen is super tough, but composites don't yield. They simply split.

Take motorcycle wheels for instance, cf wheels are fantastically light but not overly suited to road use because of potholes and debris and so on. Functioning within design parameters is fine but you can't rule out a sudden, unexpected load in the real world, and nobody wants a suddenly disintegrating wheel! So they tend to be relegated to racetracks.

Extreme example I guess, but its something to consider. I guess if you're doing finite element analysis or something similar you can always build to worst case scenarios. I guess that's the beauty of composites, adding lots of stiffness doesn't have to mean adding lots of weight.

I used to play around with RC cars and those alluminium baseplates were light and plenty tough!

When you say chassis do you mean a box section style chassis or a baseplate? If you're thinking of working with enclosed cores then you might want to check out the links to carbon fibre bicycle frame designs on here, as they typically involving wrapping cloth over a core of ablative PE form or a honeycomb.

That process is very simple, the hardest part is arguably making the core sections from the draft (if you have axis to rapid prototyping or 5 axis milling- no sweat! ). Laying the composites on top can be as simply as wrapping resin soaked fabric around the core and vacuum bagging.

Making curved sections or panels, given the above technology, would be simple. And they'd be able to withstand massive loads.

I love the idea of a curved bodyshell with all the important stuff running inside the panels The only thing I can think of offhand that uses the bodywork as a structural member is a Vespa scooter

Just some ideas. Good luck!