gilboa

Hello all, Tried going with the far simpler setup - read: I dropped the differential and and switched to two XL engines (connected directly) / v1 receiver / battery box on each side, and at least for now, it seems to work just fine. I'll update if the XL engines go up in flames... :/ Thanks all.

Given the fact that the turntable was never designed to handle fast rotation, did you have any long term issues using it as a differential axis? 1. OK thanks. 2. Sounds very interesting. I'll check it out. 3. I was planning to have two battery box, one for the drive-train (4 x XL) and one inside the turret to drive the turret and the gun elevation. I'll have to see which is cheaper, getting an additional remote + v2 + battery box or biting the bullet (price wise) and moving to BuWizz. 4. I was thinking about a add a third small motor that will "break" the output side of differential, but this will require a second differential on each side, which in turn will add additional failure points and take huge amount of space. 1, What type of gear should be used with 28z? (I couldn't find a definite answer) 2a. See item 2 above. 2b. That was my original plan. (58119 for the power-train, 64228 inside the turret to drive the gun / turret). 3. I plan to test a direct drive setup, and check how it goes. First, amazing work! It'll take me a couple of iteration (and years) to come anywhere close to your MOC. The reason I'm overshooting for 4 x XL engines drive train is simple (and kinda stupid): All the tank MOCs I've seen are fairly slow. Having served in a tank battalion IRL, I really want to recreate the sheer awe generated by ~60 ton beast charging headlong at ~70km/h Two sets of XL engines. In each set, each XL engine is connected to one end of the differential. As stated above, I plan to test a direct drive setup and see how it goes. Many thanks to you all for the answers. - Gilboa

Before I begin, thanks for the long and very detailed answer. Just to make sure I understand your point, there's not much use in using the "normal" differential as there were never designed to handle 2+ XL engines and this is the reason the 90 degree gear (cog) is slipping? I understand the general design of your turntable based differential, not sure I get the the minor details but I guess I'll be able to build one on my own. Never the less, a couple of questions on your design: 1. Did you connect four engines to this differential? Two on each side? Didn't you have issues with the output (I assume you used the turntable cog as "output") simply melting / breaking teeth of the cog you connected to? 2. How did you steer? IRL tank drives usually use a clutch mechanism to engage / disengage the driving wheels. 3. Did you connect the 4 x XL engines directly to the battery box? (And by that, avoided tripping the over current / thermal protection on the PF receiver?) Thanks again.

I considered using a direct drive like this, but decided against it (due to the reasons above). I may reverse the call if there's no solution to item A (cog slipping). Follow up question: What type of receiver are you using? V1/V2 or SBrick/BuWizz?

The previous tank iteration had one XL engine on each side, and it simply didn't have sufficient power to move it fast enough (to my liking). As for the differential, as romashkaman said, as far as I know, not all XL engine are created equal, minute RPM differences can shorten their life considerably when combined in a direct drive.

Hello, Hopefully I'm not breaking any forum rules but posing the following questions (In my defense, I'm double checked where this should be posted). Long story short: I'm rebuilding my MOC (yellow) tank, this time with 4 x XL engines, as the previous setup (2 x XL) was too slow to power this beast (I want it to be *big*), with each two XL engines connected to a differential (see picture(s) below) and to one edge of a PF V2 receiver. Currently I'm facing two issues: 1. The 90 degree non-beveled gear (cog) between the differential and the external gears seems to slip under load. Most likely I'm using the wrong part. Any idea which part I should use? AFAIR the differential P/N is 73071. 2. As noted above, I've got 2 x 2 x XL engines connected to the PF V2 receiver. Under load, it seems to cut off. Am I tripping the over-heating and/or over-current protection? Any possible solution, beyond buying SBrick / BuWizz? 2a. Assume the answer above is a resounding *Yes*. Any suggestions? Will both will be powerful enough to power 4 x XL engines + ~2-3 XL/L engines (for turret, gun elevation, etc)? Thanks! 4 x XL power pack: https://imgur.com/a/EiVx6MB

Hello, Thanks for the prompt answer (I somehow missed it). Will do as suggested. - Gilboa

Hello, New comer. I have a couple of question concerning PF, gears and differential. A. Which forum should I use. B. Given the fact that its a MOC, what is the correct post guidelines (E.g. subject, etc). Thanks, Gilboa