Hello

Maybe this is helpful to someone.

Currently i'm building a 1:20 tank, and i had a problem with the turret.

I wanted an unlimited turret rotation without some cables through the turntable, but i also don't want to have a battery pack, motor or receiver inside the turret. So every electrics should have been placed in the hull of the tank.

So this was my first try:

The problem with this solution is, that if you rotate the turret, the gun (yellow axle) is moving up and down ;-) Not really good.

So i was searching a solution and finally have the following working one:

Description:

blue: turret rotation

red: gun leveling

yellow: output for gun leveling

The green axle between the two motors has to be attached at the hull so that i can never spin.

When the turret rotates (blue) and the gun leveling (red) does nothing, everything is rotating around the center and the red and green gears are rotating at the same speed. And because the are at the same speed, the diff stands still and also the output for gun leveling (yellow).

When the gun leveling motor is on, the diff is moving because the green gears are standing still.

I have build a prototype of this and it is working very well.

The only problem is, that this only works in huge tanks ;-)

Or you could put the worm gear above the turntable, not below it, and then the gear reduction would make the unwanted gun motion negligible.

Yes, negligible, but does not eliminate it ;-)

Maybe run a diffrential through the turret with some sort of gear train connected to the turret rotation to eliminate the extra movement of the traverse. If you do this it would be Best to have it in the hull because you won't have as much room as you think ( even my 1/15 tanks are cramped) the best solution would be to just put the wires through the turret.

Yeah, putting wires through it is easy, but i doesn't want that ;-)

Maybe you have understood me wrong. I've build my tank in LDD an everything fits in it well.

Just waiting for the parts to build it..

This was only to show a solution for this leveling problem ;-)

Pretty brilliant! Like you say, making something negligible is not making something go away!

I'm gonn a try to make a more compact version

I would use the "inverse" gear of the turntable to transmit the rotation of the turret instead of leading two axle through the turntable.

then you can use a differential to add sum up the rotations of the two axles (like you already do).

Or you could move all that compensator gear train under the turret to save space inside the turret.

Edited May 11, 201410 yr by Lipko

@Tommy: Yeah, try it. That was the smallest i could build

@Lipko: I think this does not work. Have already tried that i think. Or can you make a picture of your solution?

I'm gonna try to make a more compact version for future use in my vehicles. Also what tank will you be building (if it's based off of a real vehicle)?

Leopard 2 ;-)

well i built a compacted version of this with the diffrential mounted underneath it, and i works but it has problems when the elevation gear and the turret are going in different directions, ( any idea if yours does that ?)

From these pictures i can't really see what this is doing.

Can you make a LDD of this?

From these pictures i can't really see what this is doing.

Can you make a LDD of this?

not really, my computer is really slow with ldd but i can make a vid of its operation

heres a vid of it in operation

https://www.flickr.c...291/?likes_hd=1

Edited May 12, 201410 yr by Tommy Styrvoky

I don't realy know if your solution will eliminate the gun leveling problem.

On which gear you will attach the gun leveling mechanism?

The axle on top. I might try and build your version just to check.

The axle on top does not work i think.

You must have an axle which is moving at the same speed the turret rotates, so the gun leveling stands still.

That was my biggest problem

I like your solution, this is a problem I have occasionally thought about but never figured out.

Thanks

If someone wants to build it and try it out, i've attached a .lxf of the solution i will use in my tank

TankTurret.lxf

Edited May 12, 201410 yr by DickesC

Here one more possible solution.

Very simple and without unwanted motion

Oh yes, that's really simple

well i built it and it seems to work fine but the only problem that i see is that the diff in the turret can behave like a clutch ( if too much resistance is applied it will fail to turn and transfer power back down to the green axle going through the turret)

Here one more possible solution.

Very simple and without unwanted motion

great idea, but you are kinda limited on range of motion.

a pneumatic cylinder would work well for this too

Edited May 12, 201410 yr by Tommy Styrvoky

Please have a look at my lxf.

It can not turn back the power to the green axle because this is attached to the chassis and will never move

Please have a look at my lxf.

It can not turn back the power to the green axle because this is attached to the chassis and will never move

but if both the green axle is fixed and the red axle is fixed by the worm gear then the differential turns in the turret.