model car

[bissen00]

i have to make a small model bobsled fore a high school enginering asighnment it has to be 8 inches long and no wider than 3.25 i was going to make it like a f1 car but decided not to any ideas to make it fast (we have to race them)

[magracer]

Can you describe the surface you are racing it on and the type of race? I'm thinking it will be gravity powered, but is it straight or with curves... How long? How steep is the slope?

Do you have any limitations regarding materials or others?

[drakkie]

Take care that the firction on the irons/wheels is a low as possible.make them as narrow as they get !!! Also make sure the shaft in between them is as friction-free as possible.Stick to these guidlines and it could make a serius difference.

(the wheels could be made from cassete tape parts)

[Smithy]

like a pinewood derby car...except different...

[Rockefella]

Simple design really. Most important thing is the design of the track/measure of the arc and the friction of the wheels against the surface. I made the rough sketch but I figured an airfoil shape would decrease drag and weight with miniscule amounts of life. Your best bet is to use the heaviest material you can that fits the size limitations, something like Tungsten would be great, but it's pricey.

[NSXType-R]

Lead would be a good alternative.

[magracer]

I was thinking that the wheels could go on sealed ball bearings. Get some from a R/C shop. It would smart to get the axles from a R/C car too, and some top of shelf grease (the name is something like molybidenium).