Opps. I did it again.

[Meter rat]

Had a good look at said purchase. The poor thing has definitely seen some rough use. There are a few missing parts, and a lot of the smaller parts have damage. One thing I found out after thirty odd years I had assembled two parts on my original one wrong. Live and learn.

[Herr Dr. Professor]

Meter rat: for some time I have been mystified by how Tamiya managed to get one motor to differentially power two tracks. Do you know if there is a video anywhere of how the thing works? Egad, can it be done by some kind of braking? ...clutch slipping?

[Ecam]

Early Tamiya Tiger I single motor with servo steering. Motor is removed for clarity (so is the tank).

Viewed from the front of tank. Stubs at the bottom covered in red primer are the sprocket drives.



Viewed from the rear (looking forward). The motor's pinion rides on one of the nylon gears and the two nylon gears mesh together (running in opposite directions). The black drums are the clutch brake assemblies.



Servo arm installed. Push/pull is left/right clutch/brake action.

[Ecam]

Two more pictures that might help.

Lever is held back releasing drive power to right side track (clutch is pressed toward the nylon gear).




On the right side of picture that thick shaft with the wide brass gears and crown gears are separated from each other they just run on a common shaft (notice the silver washer that split the two next to the left side's brass gear).

Also in the motor "well", notice the thrust bushing on each power shaft running from back to front. It has a cork washer and is the "brake" for the track. As the steering servo is applied the clutch starts to release. Progressively the shaft goes to neutral and then enough pressure the cork washer brakes the track.



Mike (Sassgrunt) gifted this to me and I am determined to use it some day on yet to be determined unusual build.

[Herr Dr. Professor]

Eric (and Mike): thank you! Those photos and explanation make a great holiday gift for me because I enjoy learning all kinds of stuff. Fifteen or more years ago I, ahem, toured the Minneapolis/St. Paul hobby stores with a super-modeler. I remember that bought a static Tamiya Königstiger kit and a Taigen PzKw. IV (now my desert build), as well as some books and magnifying goggles. I have always wondered if I could ever make the Tamiya Königstiger run RC. It would be fun to find an old Tamiya transmission like that. But I have enough projects (and a few Taigen Königstiger) to last and last and last. Thanks!

[Ecam]

I have no idea if it was pre built in the kit like the current dual motor transmissions are. It is quite heavy and I am sure it was from the resistor/wiper speed control days. When two channel radios were the norm and 4 channel rigs were for the elite. Mike told me they were finicky and too large for all but the biggest 16th scale tanks. Super spin is out with this trans and ironically I believe the Tiger was one of the few tanks of WWII capable of running the tracks in opposite directions (although rarely used).

I like mechanical things so I've been looking for a worthy build, not just a vintage Tiger I or II. I feel like I have to build something unusual for once! I think it could work great in a large WWI tank.

[Exhibitedbrute]

I am also told the tiger was one of the few actually capable of doing that but I am also told that due to the weight of the tank it could damage gearboxes or fetch the track off so was ordered to be used in emergency situations only. I haven’t fact checked this myself. it’s just what I’m told by someone who claims they have fact checked

[Exhibitedbrute]

How about building yourself spud. If you have a printer to do it on ecam

[Ecam]

Not sure how wide a MK4 is in 16th but I think it is rather wide. So yes the spud driving a chain drive to the track drive would be simple (3D printer or not - I have a printer but the or not would be easier for me). The current Tamiya Tiger drive sprockets do fit this old transmission.

[Exhibitedbrute]

It’s rare rather large and unique so ticks all the boxes