Pan Chassis "Lead Sled" design
by Chris Briggs
|
A while ago Jack
Stinson and I were talking about pan chassis and how well they work on wood
and plastic tracks, and how easy they are to make. As Jack says "It's not
rocket science", take a few pieces of brass and a motor bracket and your on
your way. A good chassis doesn't need to be complicated. That's the beauty
of the pan chassis it's a simple design which is easy to build,
Our chassis are
similar in a number of ways, but each is built for the specific types of
tracks we race on. Jack builds a light weight chassis for the plastic track
he runs on. And I build a heavy weight chassis for the wood track I race on.
Before I get started on the detail I'll supply you with a little background
on my track and the running gear we use in our club. The track is a 4 lane
routed road course, made from particle board and painted with a semi-gloss
latex house paint ( gray ) and uses braid for the contacts. We race both
clear and hard plastic cars in a number of classes. All of the cars have
scratch built pan chassis. Motors range from the Pla-fit 40% ( Rabbit ) we
run in our F1 and Sprint cars to the 80% ( Cheetah ) we run in our GTP
class. The hard plastic cars ( NASCAR, Sports Cars and Sedans ) all run the
Pla-fit 60% (Fox) motors. All of the cars run on sponge tires, Parma MX
blacks being the tire of choice. My track has a great deal of grip, and in
order to run well you have to build heavy to get the car to handle well and
put in good lap times. So when I say heavy, I mean heavy. The average weight
of one of my hard plastic cars is 6 to 6 ½ oz. ( and no that is not a typo
). And the reason Jack has dubbed my cars the "lead sleds".
The chassis design
is fairly straight forward for a pan chassis. I have added a cut out for the
motor. This allows the motor to sit flat with the bottom of the chassis. By
using the motor cut out you do several things.
I use a Russkit
Ajust-o-Jig for all my building. But any good jig that will keep your wheels
and axles lined up will work. I also like the jig because it is metal.
Because of the thickness of the brass stock I use, I do all my soldering
with a torch. The torch is quick and gives a good strong solder joint. You will have to make up a system to mount the body. I use a 4 point side mounting system that allows the body to float on the chassis to mount my bodies. ( Something I won't go into here. But is important in making the car handle well ) Now for weird part as Jack would say. From hear I start adding lead to the chassis. The whole under side of the chassis is covered with a sheet of lead ( I use the Slick 7 self stick sheet lead). Then I start placing lead on the top of the chassis, on the out side of the motor cut out to the front axle carrier. A strip on each side. From hear I mount my body and start testing and keep adding weight to the top side of the chassis till I get the car handling the way I want it. This is where the 6 ½ oz. cars come from.
I know this goes
against all that most of us have been taught over the years. It has always
been lighter is better. But that is not always the case, especially on my
track. Light weight cars just will not work on my track. They just can't get
through the turns with any type of speed. All the new people that come into
the club try to run light at first. But it doesn't take them long to see
that if you want to be competitive and run fast you have to build heavy. (
Just ask Dave England from the 132 slot car DL, he just joined our little
group ) The main reason for all the weight is to get the car to handle
better in the corners. With the grip my track has a light car will go into
the corner and the rear will stick and Here is a drawing of the chassis with the dimensions for the chassis and the cutouts. (NOTE- The length of the front axle tube is marked as 5/8", This is wrong and should read 7/16") Well that's how to build one of my "lead sleds". They do work great on my wood track and on the other wood tracks I have raced on, as well as the commercial tracks in the area. If you have any questions feel free to drop me a line and I will try to answer them for you.
This article was written well before the Proxy Race that Bob Ward put on last year. And this is the same chassis that I put under both of the cars that I entered. Both qualifiied well and the Ferrari placed 2nd behind Russell Sheldon's out standing lazer cut chassis. |
![]() |