[Shotimes] pinewood derby

[Leigh Smith]

Only 1-1/2 oz to 2 oz on the fronts, the rest on the rear wheels. Requires a
fairly large setback for the weight. Less weight on the front for smooth
tracks, more for bumpy ones (wood). We had one car go off-course due to a
bad bump, and it was the winning car, the last round of the finals in a 120
car race! Smooth aero helps a little, small frontal area helps more. Main
thing & best secret is axles as smooth as a mirror. Use polishing compounds,
rouge, polishing tools, dremel tool, or even a dentists drill. It must look
like a mirror everywhere. Use chrome polish & power tools. No ridges left
either. Inspect with a magnifying glass. I have spent as much as 30 min on
one axle in a lathe. Do 7 or 8 and spin test them Some will just be faster
than others. Use moly based graphite from Hodges Hobby Shop, CA. Stays on
longer. Do an immaculate 4 wheel alignment for camber and especially toe-in
(drag). Use a formica table top, slightly tilted, and a masking tape line.
The derby car must roll absolutely straight. This will require drilling the
axle holes in a drill press, and it will still need an alignment anyway,
cause it's wood. Only three wheels on the ground, one 1-2 mm up.
I'm sure I have more tips filed away if anyone wants them.
I had these tips passed on to me by by a 5 time county run-off champion, and
my boys and their proteges ruled the local pack for years. There's much more
on the web too, but some of it is bogus.
Lee


----- Original Message ----- 
From: "Donald Mallinson" <dmall@mwonline.net>
To: <shotimes@autox.team.net>
Sent: Friday, May 06, 2005 9:32 AM
Subject: Re: [Shotimes] pinewood derby


> I helped my son's build a few pinewood derby cars. The one that got the
> most interest, but was slow, was the one we built with all the left over
> parts from my modeling days.  Realistic engine, zoomie headers, spoiler,
> lots of decals and driver.   The best one was very slick and organic
> looking with nothing sticking out.  I smoothed the tires, polished the
> axles, made sure everything was straight, and then I put on a set of my
> old model "moon" wheel covers, but not before filling each wheel with
> graphite.  No need to replenish the graphite!
>
> We got through three rounds.
>
> I remember we had the weight down low and centered in the body.
>
> So Kris, and others,  give up the secrets, where should the weight go?
>
> Don Mallinson
>
> bjshov8 wrote:
>
> >I guess it's like everything that people get involved in- it eventually
gets
> >real technical and competitive.  My daughter's church has something like
> >this but they do it for boys and girls.  She and I built a few cars and I
> >built a few to enter just for fun.  Searching the internet you can find
lots
> >of hints plus a lot of people that claim to know the real secrets but
want
> >to sell them to you.
> >
> >I read about putting the weights in the back, the theory being that the
cars
> >start on a slant so the higher up the slope the weights are the more
> >potential energy is stored.  As I discovered the downside of this is that
it
> >makes your car a little squirrely and if the track is a bit uneven like
ours
> >was your car might be prone to jump the divider.
> >
> >I also learned to polish the axles and use graphite for lube.  We
weighted
> >the car a bit on the heavy side then took a drill with us to weigh-in so
we
> >could fine tune the weight to just under the legal limit.  The cars that
I
> >built were widened so that the wheels were actually shrouded within the
> >body, thinking it might reduce wind resistance but it also made the cars
> >look more realistic.
> >
> >Some of the things I found on the net looked like they were designed
> >strictly for performance and didn't look like any normal car.  I like to
> >make mine look like something- one year I made my car look a bit like the
> >Ford GT.  I wanted the car to work well but tried to remember that we
were
> >doing this for fun and if we didn't win we still had fun.
> >
> >
> >
> >
> >>It's all in the placing of the weights!  My son Colton came in first
with
> >>his version of a SHO Pinewood Derby car.  Every single Cub Scout beat
him
> >>
> >>
> >in
> >
> >
> >>the downhill portion but on the straight away, he killed 'em
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