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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 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. |
for
the beginner and the expert. And is a very good handling chassis for
both clear and hard plastic cars. Pan chassis are great for converting
static kits into slot cars, or making a old slot car ( or even a new
one ) run better. And the best part is that they are cheap and easy
to build. My whole chassis will cost about $5.00 to make up, and $3.00
of that is for the motor bracket. 
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". 
1)
It helps lower the center of gravity . 2) it allows the motor to sit
lower in the chassis so you don't have to worry about the motor hitting
the interior of the car. Without the motor cut out your motor will sit
at a up word angle, and cause problems mounting the body as low as you
want to. The other cut out in the front is to allow for the set back
of the guide. This has several advantages too. It allows you to move
the guide back very close to the center line of the front axle. Buy
doing this you are able to get your guide set back under almost any
body. This works great for some of the short nosed cars like the Scalex
Sauber Mercedes, Porsche 962s etc. And I have found that keeping the
guide set back close to the front axle also helps in the cornering and
the way the car handles in the turns. As you can see by the drawing,
I use a split axle system for the front wheels. The split axle system
allows you to move the guide back close or into the center 
line
of the axle. And allows me to run independent front wheels. I have done
a good deal of testing and have found that independent front wheels
will help improve your cars handling in the corners and do wonders for
lowering your lap times. I have found that the independent front wheels
will help to pick up as much as a half a lap or more on my track ( all
my testing is done on a 3 min. timer ) Over a no independent set up.
One important part of my set up that goes against what most of you have
been taught. Is that you want to have your front wheels planted firmly
on the track. This will help to keep the car from tipping when you enter
the corner. If your wheels are not touching the track your car will
handle poorly.
To get started you will need the following materials..... 2 pieces of
.064 X 1" wide brass flat stock.( The length will depend on the wheel
base of you car) 1 piece of .064 X 1/2" wide brass flat stock ( 2 to
2 1/2" should get the job done ) 2 pieces of .064 X 1/4" wide brass
flat stock ( each about 3/4" long, bent at 90 degrees, with about 1/4"
on the short end of the 90) 2 pieces of 1/8" I.D. brass tubing ( each
cut to 7/16" long ) 2 pieces of 3/32 brass rod ( each about 1 ½ " long,
bent into a L shape with about 1/2" on the short side) 1 motor bracket
( I like to use the American line # 3000 in line bracket ) All of the
hard plastic cars I build are based on a 2" wide pan. The first step
is to set up your jig for the wheel base of the body you will be building
for. The two main strips that make up the
pan are made from .064 X 1" wide brass sheet. Make the cut outs for
the front and rear on each half ( see diagram for dimensions ) and then
solder along the center seam. You can use 2" wide brass sheet but I
have found it easier to make the cut outs using the 1" brass. ( a Dremel
tool and cutting wheel work great for this ) With the main pan in place
position the motor bracket and take the 3/32 brass rod, bent into a
L bracket and solder these to the pan and motor bracket. After this
is done I move up to make the front axle carriers. Take the 1/8"I.D.
brass tubing and set them in place on the front axle and then take the
.064 X 1/4" brass stock and bent that into a L shape and solder these
to the tubing and the pan of the chassis. The last step is to take the
.064 X 1/2" wide brass sheet and drill a hole in one end to take the
size guide post you will be using to make your guide holder. Then
position this on top of the center seam of the main pan and position
it as far back as needed and solder this to the pan. And that's it for
the chassis. You have a grand total of 9 pieces of brass (not including
the motor bracket ) and you have your chassis done. 
load the front of the car and pop the guide out of the slot. With the
"lead sled" the weight helps keep the car running flat in the turn and
having the front wheels planted firmly on the track keep the car from
tipping in the corners. You will be able to get into the corner with
more speed and keep that speed up through the and out of the corner.
The basis chassis is a good starting point. It's simple and very strong.
Mount your body and start adding weight as needed to get the car handling
to your liking for your track. 
