DaveBcool

I am working on gearing down my Tammy Panther G.
(which has been a total pain)
Now the tank pulls to the right, about 1 foot over a distance of 10 ft

I have installed the following:
Tammy gearboxes
480 motors
Max Prod gear downs
14t pinion on motors
18t pinion on outdrives
I use a futaba 4 channel 2.4 ghz radio

I used a piece of paper to space the gear mesh
I checked track tension
I recounted all the teeth on pinions/geardowns (they are the same on both)
Everything is freshly lubricated
I reversed the motor wires to counter act the direction of the geardowns
(I alsoremoved the tammy motor connectors andsoldered in dean's)

Any thoughts or suggestions?

yellowshaker

My Feedback: (1)

I would try checking trims first. If that doesn't fix it, then do a reset on the DMD.

ausf

Hopefully you'll get a better answer, but I had the same issue with my StuG. The right side motor (Pro 400s) lags a bit in speed and start up compared to the left. I'm going to switch it out to see if it's a difference in motors, but for now I corrected it with trim.

bowlman

You may need to due a rudd adjustment on the Tamiya DMD it sounds like 1 motor is getting a little more power then the other the rudd adjust will even them out .

Thanks
Jimmy

DaveBcool

Thanks YS.
I did check the trims, and tried fiddling with them.
It did not help.

I did not think to reset the DMD.
Will try.

ausf

Good answer! I forgot about the handy rudder trim right on the unit.

bowlman

I had this happen on my Panther and adjusting rudd on DMD fixed it .

Thanks
Jimmy

yellowshaker

My Feedback: (1)

Yes, Rudder is possibly not adjusted correctly

DaveBcool

The rudder trim worked!
Thanks so much!

Panther G

Did you do a proper brake in of the motors and gear boxes. Most motors are made to run in one direction so when you reverse one it can run slower. some brands of motors have a left and a right turn. do you know which you have? It is still a good idea to run both motors by themselves for an hour or so in each direction to burn in the brushes. This will help with and odd direction motor.

DaveBcool

PantherG
I have used the motors for a year, but I just installed the gear downs to get more accurate speed/torque.
Is it wise to get new motors also since I reversed direction?

yellowshaker

My Feedback: (1)

Dave, you should be fine with them.

bowlman

Come to think about it the Panther that did this had gear downs in it the only One I've put them into all my other Tamiya TU's and Impact TU's never had that problem .

Jimmy

DaveBcool

I will see how the motors perform this weekend in Danville.
However, when I timed my panther at 25 ft, it was 1 second faster in reverse!

11.33 sec forward
10.25 sec in reverse

The 10.25 is actually the speed I want.

heavyaslead

Most DC motors that are single direction have angular slip.

This translates to faster (slightly) forward speed. And slower (slightly) reversed.

Slip is done to maximize motor efficiency and RPM at load voltage.

You may need to switch the motor connections, as the geardown sounds like it reverses the drive output direction from stock.

You could buy bi-directional motors for consistent forward and reverse speed.

Not sure if Doug will be checking reverse speed or not for this event, so be ware.

Panther G

I think he said he already reversed the motor connections for the gear downs. This is kind of strange since the motors are obviously broken in and the brushes are well set. All i can think of if you are having a pull to one side is something is binding in the running gear.

DaveBcool

There are bearings installed, and the tank is only 1 year old.
There could be binding some where along the running gear, it does seem a little jerky, not quite as smooth as it was before.
It does however seem a little smoother in reverse.
I am going with the "The motors were broken in going in one direction, and now they don't like going in the other direction" theory.

yellowshaker

My Feedback: (1)

Swap the motors to the opposite gearboxes....

tomhugill

Have you checked the wheel alignemen? It's a really daft one but I was having no end of issues on my Tamiya panther and it turned out that not all the wheels had been aligned properly. With the narrow guide horns this caused rubbing on the out of alignment wheels. Worth a look!

Panther G

Actually 1 foot in 10 really isn't much pull. Is it really hard to control? I think Joe is correct, just switch motor sides.