| An early shot of the steel frame. Here the engine / alternator assembly was installed, and I was fitting the belt reduction for the electric motors (only one shown). I decided to use a steel frame for a couple of reasons. The first was I had scaled the model 150%, without scaling the building materials. I was concerned that the thin wood body would break at this size. The second reason was because I decided to use much stronger motors, which would put more forces on the shell. By the numbers, over 300 lbs of force will be applied between the front drive wheels and the rear idlers when the motors are delivering peak power. | |
 |
The frame after a paint job and "final" assembly.
The motors are mounted and the belt reduction was complete,
but
it just wouldn't work. After the frame was mounted inside the
body, the reduction was changed to a three stage belt and chain drive. |
| Another view of the original drive and the frame. The wood boxes house the ball bearings for the pulley shafts. They and the motors swing on hinges to adjust belt tension. |  |
 |
Another
view of the shaft work. The lower belt is tensioned by
adjusting
a screw that forces the hinged pulley assembly to the left. I used wood for the bearings because I have a wood lathe. Later I got a metal lathe and I used it for the current drive reducer. |
| This is how I mounted the motors, which are about 3" in
diameter and 7" long. The motor rests on a piece of angle
iron,
and I used threaded rod to tighten the motor to its frame.
Another
piece of threaded rod tightens the motor belt. This shows version 2 of the motor drive reducer. It worked fine, but I decided I needed more torque than what this offered. |
 |
 |
This
is the body after some paint. The frame is in the background
along with the engine sub frame. The original plans provide all the details for the wood pieces. 1 1/4" square wood pieces cut from 2x4's are used along all of the wood joints for strength. |
| This is what it looks like from behind. I modified the plans by making the tank a little taller. This was to make the engine fit. As a result the rear 'T' piece is an inch taller. |  |
 |
Body side view. At this point I started thinking about the track, so the tank stayed like this for about a year and a half. Before the track was finished and installed we had moved to a new house, my father in law died, and I had surgery. Tank work was not a high priority! |
| This is the turret assembly. It is made of
3/16"
plywood and has a 45" pvc 'gun'. The gun swings up and down
on a
1/2" soft steel shaft. I had to rough cut the plywood sides
and
soak them in the bathtub for a day before they would bend without
breaking. Lots of screws to hold them in place. These pictures were taken before the rollers were installed. |
  |
  |
The turret has a wood ring glued up from two layers of 3/16" plywood, which is glued to the base ring. Wood blocks and chines attach the other pieces. The large plastic piece is a 6" pvc coupling from Lowes. To each end I glued wood disks that have a center hole for the shaft hinge. The turret rolls on six wheels harvested from a cheap pair of inline roller blades. |