[Land-speed] HP/DRAG/Traction...

[adin at frontier.net]

Hmmm, it seems Slim or someother scooter guy told me about getting
high speed wheel spin due to aero drag so all you explained makes sense.

The unanswered question:  is there wheel slip and about how much? That
is, wheel slip short of the fancy dismount (BIG spin)???

and thanks for taking the time to run through all that typing . . .

David in Durango



Quoting Keith Turk <kturk at ala.net>:

> Yes our problems were created by DRAG....  with a given weight... you
> have X amount of Traction,  If you have the HP available it will
> overcome that traction and the tires spin,  Bout that simple.
>
> So the choices are to decrease the HP to a level that doesn't spin the
> tires,  to decrease the overall drag of the car, or add more downforce
> ( think Ballast or aerodynamic aids/Band-Aids ).
>
> By doing all three of these things we increased our speed on a
> deteriorating race track.
>
> We could have decreased the HP simply by lifting our fat feet off the
> throttle a bit... but we had a really hinkey throttle set up... and it
> wasn't as polite as it should have been.... Throttle pedals need lots
> of travel and to be extremely smooth... this one had neither of those
> things... ( but it was Morse cable actuated which we felt was a
> requirement with the blower, allows you to manually close the throttle
> blades )  By taking the Blower off and running an 8-1 motor on a single
> 4 and nitrous we decreased the Hp from 1200 down to around 900hp.
>
> We increased the downforce by adding some spoiler angle.  Even thou it
> adds drag we felt the increase in pressure on the tires was worth the
> increase in drag.
>
> Last but not least significant,  we took off that Barn door on the
> motor and put on our Aerodynamically friendly, wind tunnel approved
> Hood scoop. Radically decreasing the overall drag on the car and
> freeing up the traction we had to build speed instead of spinning the
> tires...
>
> Hmmm that's about it.
>
> Keith... ( see it wasn't even rocket science... just plain logic. )