My open Cirrus (1968, probably 400kg with me on board) has the 400 x 4
wheel and Tost brake.

The main purpose of the brake is to stop the glider overrunning the
aerotow rope in the Up slack/All out transition.

It also makes a scraping noise if I use it after landing.

I've never yet met a reliable glider wheel brake. I suspect the worst
kind are those which work *almost* all the time (K21 comes to mind)
because then you might get into the habit of pointing the glider at
expensive objects!

Bruce wrote:
Anyone who relies on the ineffectual brake fitted to most older gliders
is an optimist of note.

On the 4.00 X 4 hub common to these aircraft you have a couple of square
centimetres of friction material, with non energising shoes trying to
stop around 300 - 350kg of glider moving at anything up to 100km/h. Most
are good for one retardation only, at best, then they fade severely.

In my experience, with a lot of fettling work one can achieve a brake
that is reliably weak - which is a whole lot better than the
alternative. But experience indicates that one should still discount it
ever working effectively in an emergency.

You would be distressed to see how much damage you can cause at walking
speed with a 15m single seater. Just think what a 26m+ motorised uber
bug smasher could do with all it's inertia. (although they tend to have
halfway decent disk brakes these days)

In any case the man has it right - Don't point your glider at anything
you intend to keep, especially on a downhill. There is no need to
provoke Murphy.

Mike Schumann wrote:
"never point the plane at anything valuable whilst expecting this
brake to stop it..."??????????
snip