Scudrunners

cgzro wrote: ↑

Tue Feb 04, 2020 1:41 pm

There must be a little bit of retraction otherwise the brakes would drag and they don't. Most of the little master cylinders have a spring that you push against and which pulls back on the piston when you release the pressure, that has to cause a small bit of a vacuum above the brake puck which likely pulls it back a bit. Not sure, but its definitely only a one way system unlike systems that need powerful force in both directions that have a two way piston.

Actually, I think that it is just a floating caliper that moves back and forth. Hydraulic pressure applied by toe brakes moves the piston to act on the brakes. When the brake pressure is released, O-rings called square cut seals provide the force to retract the piston. At least according to what I found through searches. No spring.

The brakes do drag a bit, in my experience. You
can hear them when you push an airplane around.

Thinking about it, the wheel/tire assembly is never
balanced on a little airplane, so when it vibrates,
it rattles the floating caliper which is going to push
the pads in a bit.

It’s all pretty lightweight stuff, suitable for a child’s
red wagon, and not to be taken very seriously.

When pilots get good brakes in light aircraft, all they
seem to do with them is flat spot tires on landing, because
they think brakes on an airplane are like brakes on
a car.

No, they aren’t. Brakes on a light aircraft are solely
for holding it during run up, and during taxi when
you want to turn out of wind and the fucker is
weathervaning.

JW Scud wrote: ↑

Tue Feb 04, 2020 11:27 pm

cgzro wrote: ↑

Tue Feb 04, 2020 1:41 pm

There must be a little bit of retraction otherwise the brakes would drag and they don't. Most of the little master cylinders have a spring that you push against and which pulls back on the piston when you release the pressure, that has to cause a small bit of a vacuum above the brake puck which likely pulls it back a bit. Not sure, but its definitely only a one way system unlike systems that need powerful force in both directions that have a two way piston.

Actually, I think that it is just a floating caliper that moves back and forth. Hydraulic pressure applied by toe brakes moves the piston to act on the brakes. When the brake pressure is released, O-rings called square cut seals provide the force to retract the piston. At least according to what I found through searches. No spring.

The Cleveland master has a return spring but not all do.