On Tue, 24 Oct 2017 23:11:15 -0400, Frank Krygowski
wrote:

On 10/24/2017 8:13 PM, Jeff Liebermann wrote:
On Sun, 22 Oct 2017 09:06:07 -0700, Jeff Liebermann
wrote:

Have you considered adding a water mist brake cooling system instead?

Curses, it's not going to work. The problem is that a very fine water
mist sprayed at a red hot brake disk will vaporize (evaporate) the
tiny water droplets before they hit the red hot brake disk. That's
nice for evaporative cooling the air around the brakes, but does
nothing to cool the actual brake disk. To do that would require
larger droplets, a higher velocity droplet spray, or both. Dumping
liquid water on the brakes would also work, but that's like having
your own private rain storm, which was the original problem.

Grumble...

No problem. You pump it into the right end of a hollow axle, and provide
channels connecting that with the inner hollows in a double-sided disc
similar to an automotive disc, like this:
http://www.autopartsapi.com/eEuropar...169e817e2b.jpg

The water flows out radially, carrying heat with it but leaving the
braking surface dry.

Yep, that will work if we can figure out a way to get the water out of
the hollow axle, through a series of holes drilled into the axle,
without weakening the axle. Cooling channels would make the brake
disk rather thicker. Never mind spraying the bicycle and rider with
scalding hot water or steam while braking. Fenders for disk brakes?

I was hoping that it could be done without any major modifications to
the existing disk brake system. It might be possible to modify the
brake shoes to inject some cooling water. That would go directly onto
the hot brake disk, which is exactly where it's needed most. The
water would cause some slippage, but would evaporate instantly when
red hot. For lower temperatures, the water would simply be turned off
and not used. This might cause some "interesting" braking effects at
the transition point, but I think that can be managed with practice.

You keep forgetting that for Joerg, weight doesn't matter! ;-)

It should matter. Much of Joerg's ride is probably airborne, where
weight is important. Perhaps some fins or wings will make it feel
lighter.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558