Two rotational motors

[MichaelC]

HI all,

Quick question to see if anyone has tried to install two rotational motors on a tank. My JS-3 turret is absolutely huge, and because it is a resin kit, it is heavier and also there isn't a mounting spot for the rotational motor so it was simply glued on the upper hull. What I am finding is that it doesn't work all the time, at different times it will get stuck and the cog would slip. What I have in mind is to run two rotational unit off the same feed from the MFU, not to expect two fully powered motors but rather split the load to two different set of gears.

I have also tried replacing the motor itself but I believe it is the cog and gears that is not getting enough traction so I am hoping putting in two sets will help.

Any ideas or advice would be much appreciated.

MichaelC.

[PainlessWolf]

Good Afternoon,
Michael, a single toothed gear mounted on a pin opposite the motor gearbox across the diameter of the toothed ring should be enough to align the ring and keep it pressed against the teeth of the cog in the gearbox. Should be easy to mount and doesn't need to be powered, just needs to freewheel so as the ring turns, it does as well. Should be no additional draw on the engine in the gear box to as it is only one gear and not connected to the box.
regards,
Painless

[MichaelC]

Painless,

Is the idea that the cog and the gears when under load pops out ? Also, isn't it easier to find another gear to mount on the opposite side then a single toothed ones (I don't know where I would find a gsingle tooth gear........). You don't happen to have a picture of this set-up do you ?

Thanks !

MichaelC

[Tankbear]

I think what Painless is suggestion is have the turret gearbox mounted like usual, then opposite side mount another gearbox which is stripped out of the motor and all the gears except the final drive. In essence the dummy gearbox is there to keep the turret gear cog solid allowing the powered gearbox to do the intended job.

Ian

[Tankbear]

Also try a gearbox from another tank, I've had a few where the final gear is out of shape and tends to slip rather than turn the turret. Long shot but worth a try before doing other modification.

Ian.

[PainlessWolf]

I think what Painless is suggestion is have the turret gearbox mounted like usual, then opposite side mount another gearbox which is stripped out of the motor and all the gears except the final drive. "In essence the dummy gearbox is there to keep the turret gear cog solid allowing the powered gearbox to do the intended job.

Ian

Sorry for the slow return. Work is a bit crazed today. Tankbear has his thumb firmly on what I was thinking. A duplicate gear to keep the turret ring pressed against the powered one.
regards,
Painless

[hawkeye3guns]

Hi micheal
Fitting two powered gearboxes to the turret ring should not be a problem provided they are the same type and they are wired in parallel,ie. same supply to each motor at the same time, (Not in series where you go to the first motor and then the second ). Each unit will only draw the current it needs to operate. and the load is shared between them. The most important thing is to check rotation of the units before fitting to the rotation turrent ring. and check they are going the same way . its been known to get it wrong.
We use dual and sometimes even triple motor gearbox units as boosters in our feed systems. if there is a heavy load to move.
You will have to check the current being drawn by the motors to make sure you are not overloading the mosfett in the MFU but I think you should be okay the HL turret motor on my 1/12 abrams (which I run on 12V) only draws 0.56amp at full speed.
regards Denzil.

[MichaelC]

Thanks guys........ I tried both of the methods last night, the one with the dummy gearbox on the other side didn't work, but I have success when I parallel wired the two sets on. I really think that the turret was just too much of a load for the one contact point of the single gear box, so when I have two on it splits the load evenly and created two contact points for the gears to catch. The upshot is that it runs slower (very slightly) but very steady which is actually more realistic. I might do that for another one of my tanks that has a heavy resin turret and has issues with rotation occasionally.

P.S. Obviously this entails the cutting out of the notch for stopping the 360 rotation on the cog ring..........

MichaelC

[PainlessWolf]

Good Morning,
What is important here is that you got it to work. ;o) Excellent job! Good on Hawkeye for the useful information.
regards,
Painless

[ALPHA]

Hi Micheal... think you might know this trick already... it was given to me by a fellow modeller and works really well.. I used it on my Fov Sherman and Kv2 so far.. and it really smooths out the rotation
All you need is a compass ... a sharp exacto knife and binder dividers
Here in the States the dividers are sold in packs... less than two dollars for about six thin plastic sheets ... you should be able to make two per sheet maybe three...depending on the inner diameter of the turret
Anyway...all you do is cut "O" shapes... slide it under the turret before fastening it to the hull and spin ring ...it really helps especially with the porous resin cast stuff..and the heavier stuff as well

Good luck

HAPPY TANKING

ALPHA