Wheels exposed?...

[F3W]

I wanted to discuss about Aerodynamics...so would you say that having exposed wheels are more of a drag in the whole scheme of things aerodynamic or do you feel that it doesn't make a difference?

I think that having them out in the airflow will cause more drag since they are not part of the body design...as the air is pushed around the body, it hits the tires and suspension and breaks up the air causing turbulence...this would cause unwanted air to circulate on the sides of the RT which could be very dangerous at higher speeds...this might cause the RT to start fish tailing.

I believe that the ultimate design would be to completely cover the entire wheel opening...this is the ideal way to push the air around the front wheels and around the RT...the only problem that I have not thought of yet, is how to build a cover that is not cumbersome to remove when you get a flat?...I suppose you could use denzel fasteners to hold it on but that would require another tool...I think a full tilting front body piece would be my choice...clean sides and less complicated plug making.

Well, that's all I have for now...think I will go back to my design board.

Dave

[3verse]

I'm going to build a one-piece body out of fiberglass -- one that covers the front tires. Though I think it will help with aerodynamics, I'm also concerned about fender laws. Most states require that your tires are covered by some sort of fender, so if your body covers your front tire you kill two birds with one stone.

The question is body design and aerodynamics that I have is how do you know if you've built an aerodynamicly effective body without extensive testing and a wind tunnel? I know there are basics that you can follow, but do you really know until you drive it down the road?

[F3W]

I guess you could build a small scale model and use a blower from a shop vac to test your design...a small string on a stick can be used to see the results, the result should be a sting that has very little movement after the air flows past the car...most everyone knows that the teardrop shape is ideal one...it will also determine on how it cuts through the wind, how it is split and pushed around the entire body...another important factor would be to have a really smooth bottom so there is little turbulence...the design needs to be able to create a natural vacuum that will keep the RT sucked down toward the road...this is how the new cars are designed to operate in NASCAR.

I am not an aerodynamic engineer, but I guess if you can find a way to measure the air going into the tube VS the air coming out the other side would determine the cd...I will check google and see if I can find a program that might be available.

Dave

[srx660]

The thing i notice is at lower speeds aerodynamics does not account for that much of a speed improvement. Look at the racing bicycle which a few years ago started having carbon fiber wheel covers on them. Have you noticed that few use them anymore? I don't think there was enough speed improvement over open wheels to justify having them.

At the other end of the scale, the land speed vehicles all look like blobs with everything enclosed in a single unit body. It looks like ground effects won over pure streamlining. That's why the Thrust SSC went 300 mph faster over the Spirit of america design.

Personally i like the covered wheel designs. Maybe its because i ride motorcycles and don't like the rooster tails off the tires in the rain. My own idea is fully faired wheel covers that might include them looking like they are open wheel with painted on tires.

SRX660