"Bryan Savage" <b.a.savage@earthlink.net> schrieb:
> <body text
> Pork Pie #2 ---that length is speed.
>
> A) What about 'skin friction' ? Is it a large factor?
>
> B) I have read that the longer the distance the air travels along the body,
> the thicker the boundary layer gets and the more unstable it becomes.
>
> Please comment on 'A' and 'B'.
>
> Thank you,
> Bryan
Hi Bryan
A) - skin friction is more important in water than on land - but it's
important, too. if you got a glss polished surface is much better
than if got a rough linen like a soft (top) roof) on a
convertible. But sometimes you need dents ih - see golf ball......
B) if you use the 6 degrees rule, the length can be "long". Our cars
will never be over this limit. The real problem developed on
crosswind and if you be very long on turning, because the length
produce a stronger sideforce - so longer the body is. Means, if you
turn left - on the front the left side pressure and on the rear the
right side pressure works again the body. If you get now a crosswind
the body can create a "torque", especially if you got not a flat
bottom like Jack Costella. If there is too much distance between
underbody and ground you can be lift.
Hope my explanation is clear enough.
See ya
Pork Pie
|