Bee Firearms has moly.
Karl
"Wayne Cook" wrote in message
...
On 7 Nov 2005 07:56:27 -0800, "tillius"
wrote:
Why would you want to weight the wheels of a Pinewood Derby car?
Adding
weight at their periphery will increase the rotational inertial of the
wheels, and they will accelerate more SLOWLY than unweighted wheels.
Just
the opposite of what you want. But I may be missing something...
Because the track we run on has a very long runout at the bottom of the
slope. I was thinking that the rotational inertia would cause the
wheel's RMP's to decay slower on the straight away. That, and moving
the weight from the body to the wheels would decrease the friction
between the wheel axels and the wheels.
I think it's a bad idea to weight the wheels but go ahead and try
it. Experimenting with these things is good for the kids.
I'm still disappointed that the local club did away with the
unlimited adult class. It was a lot of fun and allowed the kids to
learn. Of course part of the reason they outlawed it was because of
me. I always had some outrageous design which looked sure to win. The
funny thing is that only one of my cars ever won the race and it was a
powered car thrown together in about 30 minutes just before the race.
I never had a lot of time to work on many of them since I was also in
charge of setting up the track and much of the other work that went
into the race. The powered car was simply sawed out quickly on a chop
saw to get rid of excess wood. Gutted a old VCR for the motor and
friction tire to run on one of the car wheels. Clipped three 9volt
batteries together. Wire a on and off switch and a micro switch on the
front for the starting gate to keep the motor off till the gate
dropped. Some sheet metal and screws to mount the motor and a bunch of
hot melt glue to hold everything else. That car won the race. Funny
though they never did have a unlimited class race after that. :-)
But it sure was fun to race the 5 lb ball bearing wheeled car even
if it never did win. I took a piece of 1 1/4" pipe. Forged one end to
look kind of like a DC-3 nose. Put steel axles through the middle.
Filled full of lead (and I mean full with the car being the max length
allowed). Made wheels for masonite pressed over ball bearings. That
car made everybody stand up and notice. But it never won a single race
even after I melted all the lead out to reduce it's weight. It did
great on the straight away but took way to long getting up to speed on
the slope so it always lost.
The first year I lost to a guy who took his old cub scout propeller
driven rocket and made a base for it. He used standard derby wheels
and filled the base full of lead. But the prop gave him enough of a
boost to beat me.
After they outlawed the unlimited class I concentrated on design.
Helping my daughter come up with designs that brought home at least
one trophy a year (some years we brought home 2 or 3 what with the
adult class and more than one car entered into it). In fact some cars
just kept bringing home trophies for years since we'd enter the old
cars into the adult class (we had to pay to do it so it was for a good
cause).
The last few years the local Awana's club has gone to the boat races
instead of the cars. In this case we kept bringing home race trophies
since I taught my daughter how to blow them properly plus I always
streamlined the boats. In fact my standard design for the boats is a
tri-maran with much lower water friction that most boats. But we never
got a design trophy for any of them.
Looks like I won't have to worry about that this year though. Since
my daughter got older and decided to not do Awana's this year. I may
end up being roped into the race again though since the water trough
tracks are stored at my place (I built them from my own money).
Actually the finish gate for the car track was built by me as well
though somehow it ended up being stored somewhere else the last year
or two of the race.
I may be wrong, but since we've got another year to prepare, I was
thinking we could set up a small test track in the basement and try
different configurations. It would make a great science project for the
kids as well.
Sounds great to me.
BTW, while I'm on the subject, is there a better lube than graphite
powder? We tried teflon and graphite this year and the graphite
definitely outperformed the teflon by a HUGE margin.
Moly is what you want in powdered form. Harder to find than graphite
but much slicker.
Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm