Kappe

My XV01 "Evo"

ejtnt

It really depends on the surfaces you run. If they are very mixed, meaning going from low to high traction, it can come in handy. What it helps with is protecting some of the gear from getting worn too quickly. A particular weak point is the idle gear in the front gearbox (part BG1 /51506).

Raman

iTrader: (60)

fyrstormer

I always use slipper clutches if they are available. I don't care about the minor weight penalty, but I do care about being able to mechanically limit the maximum torque sent to the wheels. This chassis doesn't have the same problems of breaking drivetrain parts like a monster truck has, but nonetheless, in low traction conditions I want the slipper clutch to slip instead of the wheels, because that way the wheels can still steer the car. If the wheels are spinning wildly, steering is compromised.

Raman

iTrader: (60)

You’re describing traction control, which is not a slipper clutch.

A slipper clutch will slip on high traction, not low traction. It will also slip on high or hard impact, eg after a jump, when the tyre that is spinning in the air, hits the tarmac and the wheels velocity is changed in an instant due to traction from tarmac.. thereby the slip in the clutch pad absorbs these forces.

In order for it to slip on low traction, you would need to have it so loose.. that it’s continously slipping which would result in burning of the slipper pad and lots of heat.

fyrstormer

I know what I'm describing, thanks. It works just fine on low traction surfaces, and you are incorrect about the slipper clutch overheating. If I were suggesting running the slipper clutch loose on a high traction surface, then you would be correct that the frequent slipping would overheat the pads. But when the slipper clutch is loose enough to slip on a low traction surface, the amount of pressure on the pads is minimal and the pads don't heat-up very much.

The amount of heat buildup is not actually related to the amount of slip, it's related to the amount of power being transferred through the clutch while it slips. I'm sure you've had the experience of skidding on carpet when you were a kid -- even if you only skidded a couple feet, you still got rug-burn, because the amount of power being transferred from your moving body to the stationary carpet while you were skidding was very high. Whereas you can slide on a wet tarp (i.e. a "Slip 'n Slide" toy) for hundreds of feet, and you'll never get a burn from it, because the amount of power transferred from your moving body to the stationary tarp is very low.

Likewise, when the slipper clutch is loose enough to slip on a low-traction surface, the amount of power transferred through the slipper clutch is small, so most of the motor's excess power is dissipated as electromagnetic drag inside the motor itself, rather than as heat in the slipper pads.

Here is the slipper clutch I run on my FWD XV-01 rally car. It has never even needed adjustment, much less pad replacement. I did eventually fill the rest of the holes in the gear with friction pegs, though.



I agree that real traction-control would be a very cool feature. I shudder to think of the cost, though. Even if the traction-control functioned by detecting a runaway acceleration of the motor, so it could work with just the existing motor sensor and without requiring any extra wheel-speed sensors, RC companies would still charge us an extra $100 for that feature -- and someone would be dumb enough to pay them for it.