This was the first Tamiya tank that I purchased. It came with two gearboxes and the DMD-T01 controller. I had always intended to make it full function.

I started by mounting the ring gear out of my Sherman to the turret. This ring gear has allot smaller diameter then the one for the Tiger 1. This allowed me to use the Porsche turret mounting without modification. Instead of trying to recreate the flimsy metal bracket that Tamiya uses to mount the ring gear, I choose to install a .1” thick styrene disk. The disk was cut a few thousands of an inch larger in diameter then pressed in place then glued. It is incredibly strong compared to the Tamiya method.

I wanted to be able to remove the top of the turret with the four screws Tamiya used. But this presented a problem with the gun mount. On the two channel R/C version, in order to remove the top of the turret the gun barrel needed to be removed, then the mantel. Then the top of the turret could be lifted up and slid forward over the mantel/barrel mount. This simply would not work with a recoil installed. The solution I devised was to cut out the section of turret below the gun and behind the mantel from the turret top and glue it to the bottom.

To make this cut nice and straight I used my hobby table saw with a thin diamond impregnated blade. Once the section was removed I cut two strips off the out side edges. I then used .02” styrene plastic as a backer and glued the two strips to the backer. Doing this reduced the blade thickness (times 2) wide gap between the lower section of turret and the top to just a few thousands. The gaps I created  will be filled in later with strips of styrene and filler.

The gun barrel, mantel mount and recoil mount all presented a new set of problems. First the barrel. I knew the section of barrel I needed to replace was slightly greater than ½”diameter. I went to my local hobby store and purchased  the largest styrene tubing they had, ½” outside diameter, and for grins the next size smaller.  I cut the barrel off at a groove in the barrel. I am glad I purchased the smaller tubing so that I could simulate these grooves. I ended up sacrificing the groove were I had cut, for strength, gluing the ½”OD tube to the remaining barrel. I was left with an odd step in the barrel from the .5” tube to the .55” barrel, I filed this down to match the tube. The piece I added ended up being 6 1/4” long! In order to prevent snags when feeding the flash strobe through the barrel the smaller styrene tube was also cut to 6 1/4”.

For the mantel I would need a tube with an inside diameter of ½”, but the hobby store didn’t carry anything larger and I was told they have every size available. So the hunt was on for a plastic tube. Some may think I am crazy looking for tank parts in jewelry aisles, but guess what I found one aisle over in the knitting/sewing aisle. Giant plastic knitting needles! Don’t ask my how to use them, but with a little reaming and sanding it was perfect. I cut a short piece (approximately 1 ½”) off and glued it to the back of the mantel. Since the mantel is square it made it easy to locate the quadrants of the tube to drill pilot holes for inserting mounting studs. I then reamed the holes to just under 1/4” and pressed in 1/4” styrene rod. I then used Pro weld to weld them in place. Once dried I sanded the ends of the rods that protruded into the inside of the tube to match the tube ID. I then drilled out these studs to accept screws.

The recoil unit is mounted up-side-down. This allowed for full elevation. The mounting is pretty simple and made of .1” styrene. The recoil is modified so that the barrel retracts with the long spring instead of the motor, creating a more realistic look.

The elevation gear box mount is even more simple. It is bolted to a small piece of styrene that in turn is screwed to the turret floor. After these pictures were taken I added a spring to pull the recoil towards the turret floor in order to take up the slop in the elevation gear box.

I mounted the rotation gear box towards the front of the tank, to allow room for a speaker in the rear. Since I used such a small ring gear the guide rollers had to reach in quite far. If you look closely at the roller in the front, you can see where its mounting stud is located, right underneath the opening for the tab on the turret for holding the turret in place. These studs would interfere with the turret tabs and prevent the turret from rotating. That is why the rollers are mounted a little platforms. The studs for the platforms pass through the hull and platform to provide a mechanical connection. I felt simply gluing them to the inside of the hull would not be strong enough.

The speaker box turned out pretty nice. I left it for last because I thought it would be simple. I was wrong, it took 2 hours to make. The box needed to have a step in it to allow clearance for the track tension mechanism in the rear of the tank. The speaker box was constructed out of .06” styrene. And is one tough little cookie once glued together. The down side to this speaker box is it’s location. This King Tiger hull is narrow. I was not able to place the speaker under an opening in the hull.

A few construction notes. When ever I glue styrene to styrene I use the Pro weld. This stuff works great. It chemically melts the plastic together. I use CA glue when ever I glue something together that I may want to remove later ( like a shovel). So I will apply a tiny drop under the part. The Pro weld uses capillary action to spread between the two mating surfaces thus bonding the entire surface together making removal much more difficult.
When mounting the rotation gear box and guide rollers, I first centered the turret to its opening by building up three sets of styrene strips. Then I wedged these in between the turret and the hull opening 120 degrees apart. I then mounted the gear box and first roller, then the second, then the third. By building-in-place I was able to hold very tight tolerances, measuring off the ring gear to locate the rollers center. As apposed to laying out the intended pattern and installing all three rollers at once.

Overall the conversion took approximately 15 hours of actual work (not including the trips to the hobby and hardware stores). The operation of the turret mechanisms is silky smooth. Since the turret ring gear is considerably smaller, the turret rotated fairly quickly. In order to compensate for this I programed  the stick throw on the controller to 60%. I did the same for the forward and reverse to slow the damn thing down. I wouldn’t be surprised if stock scale speed was around 60mph. After owning this tank for over three years and only being able to drive it around, it brought me great happiness to hear it’s V-12 start for the first time. I was very fortunate, during testing the only two issues I had were, the wires to the recoil motor got caught in the recoil gears. And it was necessary to add a spring to rid the barrel bounce from the slop in the elevation gear box.

Now that the mechanical work is done, I will start on the detailing, opening the drivers hatches, adding grills and Zimmerit and weathering.

Finally spacial thanks to my Tiger 1 and Sherman for donating components to complete the conversion.

Tamiya King Tiger DMD Conversion by Patrick Salm