[Lotuswins]

Hi Luke,

I thought I'd share some thoughts on the sabertooth 2 x 12 Motor Controller since I now have the tank working well. 

So the tank I have the TCB installed in is a Taigen Panther which I purchased in kit form, with 4:1 gearboxes, 390 motors, etc.  The wheels are ball bearing with no rubber on the circumference.  The gearboxes have bushings, except on the output shafts have ball bearings.  Idler is ball bearing also.  The tracks are really smooth in running, no stiffness in the pins. 

When I first put the tank together I had a IBU2U installed, but the tank would not turn well, especially on carpet.  To do a sharp turn I would have to stop completely so static friction would take effect and help it turn.  Not good if you are trying to battle, or just drive it around.  Since I was having other issues with the IBU2U, and since I got a new 2x12 controller for Xmas, I decided to swap out to the TCB.  After rearranging the internals of the tank to fit the 2x12 three times, I finally got it all to fit inside the tank without the slipring trying to pull the smoker plug off the TCB when I rotated the turret.  Don't get me wrong, the Panther does have a lot of room inside, but the sabertooth 2x12 has large heat sinks to deal with which made things awkward.   I even put a shield between the TCB and the underside of the turret so it could no longer catch up on any wiring, etc. 

Upon driving the tank, it was really transformed.  No more motor whine.  It will crawl much slower even than the IBU2U/IBU2.  And it now turns. 

I think the turning is due to the regenerative braking that the sabertooth has, since if traveling at full speed the nose will actually dive a little when stopping, and it stops fairly quickly whereas with the IBU2 it would kind of coast (built in inertia). 

Just thought I'd share some impressions on the controller hooked to the TCB.  Thanks again for all those involved with the TCB, it is really awesome.

Jerry

[LukeZ]

Thanks Jerry for relating your experiences. I personally haven't tried the 2x12 but I'm glad to know it works.

I certainly have experienced the "no turn" phenomenon, especially on carpet. This is a serious problem with Taigen's newer gearboxes when used on heavier tanks with wide treads and lots of metal (Panther, King Tiger, Jagdtiger, etc...) The gearboxes have very little friction which in other applications would be considered a good thing but tanks rely on this friction for turning. What can happen as you found out is that you can command a turn, the motor on the inner track will be powered off, but the tank will keep going straight because the inner track just freewheels and the outer track has enough contact and friction with the ground due to weight and size to just keep plowing the model forward.

To be fair I don't think this is a problem with the IBU2. Your theory about the regenerative feature of the Sabertooth introducing friction is interesting and it may be correct. I've encountered the same failure to turn in my Jagdtiger with Taigen gearboxes using a Sabertooth 2x5, but it stands to reason the regenerative effect would be stronger in the 2x12. (The 2x5 is actually not quite powerful enough for the Jagdtiger generally so I don't recommend that setup but I was just doing some testing).

The Scout ESC has a feature to force drag the inner track by using brake commands to help overcome this turning problem but of course that doesn't do most people much good...

Anyway, I'm glad you're enjoying your TCB and thanks for the review!

[jhamm]

Hi,
i have much experience with heavy Tank models....
Out of the box the most models not able to make a sharp turn on carpet or wet grass.
The torsion bars need to be tuned!
Bend two or three torsionsbars in the middle hard down.
The weight pressure of the tank will concentrate on a smaller Point oft the tracks.
The effect is the front and the edge of the tracks have lower pressure and the tank can easier turn.

[Lotuswins]

Hi jhamm,

I didn't even consider modding the suspension to enable a better turn, brilliant!!  Thanks for the suggestion, I'll store that away for future use since the Panther is now turning.  The last time I tried to 'tune' a torsion bar though, I broke the darn thing.....8^).   I can visualize where concentrating the load of the tank in the center will alter the moment of friction (new 'tanker' term?), reducing the force needed to rotate the chassis. 

thanks, jerry