Subject: Help me build an aerodynamic car

I have been getting into the hobby of building model rocket cars, but I have 
had some problems with overpowering them and having them lift off the ground, so 
I was hoping you might be able to help point me in a direction where I can use 
physics and downforce that I can apply for the next car I build. I would like 
it to run on an Estes D or E engine. This is purely for a hobby, not school. 
thanks for you help.

Re: Help me build an aerodynamic car