[s-cars] alignment Q
LL - NY
larrycleung at gmail.com
Wed Jan 14 20:23:34 PST 2009
Dying to see it. And in terms of absolute gain in KE, it's based upon the
difference of height, so if the track levels off at the bottom, then yes,
having the weights as far back as practical (whilst maintaing front axle
loading) would give you an incremental gain.
If the wheels are NOT a fixed size, diameter, etc, the most gain you can
make is to make them as small a radius as possible, with whatever mass they
have as concentrated towards the centers of the hubs as possible. And as
noted, camber could intro scrub, and if you can try to get the car to two
wheel, there would be less friction (and rotating inertia) because only 2
wheels would be required to rotate (so long as you can keep them from
touching and trying to spin up). It's just like a turbo, smaller mass,
smaller diameter, quicker spool.
LL - NY
On 1/14/09, pkrasusky at ups.com <pkrasusky at ups.com> wrote:
> thanks Lee
> my online surfing seems to reveal that yes all the way in back provides the
> most kinetic energy but yes does offer float to the front. SO, next best is
> just fore of the rear axle.
> our design dictated minimal cuts to the supplied block and then adding
> balsa flares and cockpit - so we were WAY OVER WEIGHT. So we swiss cheezed
> the bottom, with most of the holes in front, then center, then shallower
> near rear axle. We're right @ the 5oz max and distributed with a rear bias
> I told him from the get go tho we're going more for best in show than
> speed. Winning both would be teets tho 8-).
> YES - I most certainly DID make him do 'some' of EVERY step. I held his
> hands running it through the jigsaw. He power sanded. Etc. Just that I
> had to take over quickly as his little puny girly mon 6yr. muscles would
> fatigue. Oh and I did all the drawing of the profile and shaping of the
> Wet sand clear coat tonight heh heh.
> I'll post up pics when we finish it Fri.
> -----Original Message-----
> From: Lee Levitt [mailto:lee at wheelman.com]
> Sent: Wednesday, January 14, 2009 4:09 PM
> To: Krasusky Paul (WQQ2PXK); s-car-list at audifans.com
> Subject: Re: [s-cars] alignment Q
> Can't tell you about alignment. I can tell you that weight
> distribution matters a lot. I think the prevailing wisdom is low
> and in front, but it would be fun to test that with your son.
> You can hollow out the car and then place weights (if this is
> still legal) to put the weight where you want it.
> I found that having a couple of test vehicles was helpful...the
> junior partner gets nervous when his car turns into swiss cheese
> during testing. :)
> Also, by the way, the physicists in the group will run extensive
> calculations to tell you why having the weight in the back
> provides more acceleration. What they don't realize is that road
> holding turns out to be more important than the incremental force
> of gravity -- if the car doesn't stay on the track, etc.
> Have fun. It's a great bonding experience. And let the junior
> member do some of the work. :)
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