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Someone posted a link a couple of days ago to a chart of the torque/power of various disc brakes. Anyone remember where it was?
I'm looking at using a disc brake set at work to apply torque to a rotating shaft. It's likely the torque will be pretty high, and will be applied for long periods of time, so may have to look at motor bike brakes (which may be a bit ott and £££) or a very large homemade disc rotor, but I'd like to keep things compact really. Guess it could all get a bit hot too.
If anyone's got a (verified) suggestion of what torque a normal disc set could apply to a 203mm disc, that'd be terrific. Otherwise I'll have to work it out from dynamics of stopping rider + bike decelerating from 20mph to zero in x seconds with 26in wheel and no slip etc...
Cheers!
Gareth
The graph is from bike radar.
It's on this review.
http://www.bikeradar.com/gear/category/components/disc-brake-systems/product/code-brake-10-37431
Not sure if there is another article with more information regarding their methods somewhere on the site.
If you are going to apply the load for a long period of time I think you will overwhelm the heat capacity of MTB disc brakes very quickly and possibly even motorcycle ones. I have cooked 'em on the tandem dragging them at slow speed with high loading in a minute or so - low speed = no airflow and high load = lots of heat.
You can get second-hand motorcycle discs cheaply.
I've once used something similar using a 600 mm custom machined disk and a pneumatic brake off a forklift (if I recall correctly)! If you're looking for high energy dissipation then I'd say a bike brake will die quickly. Do the sum for the power of a bike brake to see if its anywhere near the order of stopping power you need.