Direct Drive to Diff E Revo Build

[sikeston34m]

Originally Posted by aqwut

have one in my BlackJack 55" Cat boat (Currently Being Re-Painted)... planning to put another one on another GST 7.7 Roller... I almost have enough parts to build 2 more GST Rollers... but I'll need to get my hands on another 40.160WK.. I'd rather wait until Lutach over there get's that Custom HV ESC made...

I have a feeling what you will run into on the GST conversion is issues with building diffs that will hold up to that kind of power.

Get us some vids of the boat and the GST if you can. Can you actually get a prop for the boat large enough to make use of the torque this thing can make?

Unsprung weight. Let's talk about that. A Motor in each wheel setup would have a center of gravity that would be unbeatable. The bearings in this motor are HUGE and appear to be up to a good amount of abuse. Not only that, the power isn't even being transferred through the output shaft anymore. The output shafts new job would be to just hold everything and keep it spinning true. It's now an "axle shaft" more or less.

With advanced Electronics and programming, we will have independant traction control. A slipperential would be a matter of programming. So would "diff slip".

Diff slip would be a matter of limiting amp draw based on steering angle. An ESC controlling this would become more of a PLC.

I really look for this to become a reality with full scale on road Electric Cars in the future.

The drive motors will be sensor based to smooth things out and completely eliminate cogging and erratic behavior.

No drive train! Can there be a more efficient way? How about one that's going to hold up longer? About the only "wear item" in this is the bearings in the motor.

[ilpufxit]

For a crawler, you're absolutely right, keep the cg low. For speed though, your suspension can't keep that much weight on the ground going over bumps, too much momentum. Could work well on a totally smooth surface.

I like the idea of motors where the diffs go, 2 motors opens up a whole range of control options.

[sikeston34m]

Originally Posted by ilpufxit

For a crawler, you're absolutely right, keep the cg low. For speed though, your suspension can't keep that much weight on the ground going over bumps, too much momentum. Could work well on a totally smooth surface.

I like the idea of motors where the diffs go, 2 motors opens up a whole range of control options.

Aaaah, I see your point. On road would be alot different and would work much better.

I like the idea of putting motors where the diffs go also. Aside from redesigning the bulks to hold them, this is going to be like running locked diffs in the front and rear.

How do we use front and rear motors, and retain our diff slip?

We've talked about an inline with the shaft slipper clutch here several times. How about instead have a centrifigal clutch in the wheel hub? The hub would have to spin up some before it would gradually apply torque to the wheel rim. Let's make this run on a large one-way bearing so when we put on the brakes, it will stop.

This setup would only "cushion" in forward, but who runs races in reverse?

[ilpufxit]

Locked diffs would be a problem for sure. The whole concept of direct drive really gave my little brain a stretching but now that I've thought it through, I'm thinking maybe two outrunners back to back in the same center diff location could use a fully electronic system for optimal everything, ie traction control, stability, ABS, the works. It could be a quantum leap in controllability. Is there a software engineer in the house?