On 2014-10-27 09:44:36 +0000, Neil Williams said:

On 2014-10-27 09:22:46 +0000, Roland Perry said:

That sounds fine if you aren't attempting to put any power on the road
through the 'spinning' wheel. I'm looking at the case where you want
about half the power that would otherwise be sent through the rubber to
remain.

Then you apply partial braking, the effect of which is to send it to
the other wheel (with a small loss via friction).

Imagine, say, you have a mains-pressure water tap with a Y piece added
to it. The Y piece is large enough to take the maximum flow from the
tap on either side (the cross-section of each side of the Y piece being
the same as or greater than that of the pipe feeding the tap). You
place your hand over one side of the Y piece completely - all the water
goes out the other way (this is the effect of braking one wheel fully
with a non-locked diff). You release the hand a bit and some water can
flow out of the "blocked" side - this is the effect of partially
braking the wheel. You will note that in neither case is significant
force applied to your hand.

You partially block both sides - such that the "engine" is having to do
some work. In that case, there is force applied to both sides (on one
side the road, on the other side the balancing effect of the brakes),
though. This is what it would be like when the system applied partial
braking. I guess what you have is that the brake on the "spinning"
side is having to apply the same force as the wheel is applying to the
road on the other side, which as it can stop the vehicle it's probably
more than capable of.

So I suppose a bit of both. But the fact is (a) it works and (b) it's
simpler and cheaper than locking or limited slip diffs.

Neil
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Neil Williams
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