Water Brake?

[jb24 at chrysler.com]

>>>>Well, while we're on a roll, here: I looked in the archives and
found
only a short, inconclusive discussion once about building one's own
WATER BRAKE for the heart a homebuilt dyno.

Most of my testing will be on a torqueNthrust stand (just about
completed) with the varying load coming from a pitch-adjustable prop
(application is aircraft-auto engines, anyway), but I thot it might be
good to explore just how hard if would be to also build a decent
water-loading device. (Mech. friction brake ideas need NOT apply, thank
you....choosy beggar, ain't I, heh.)

Soooo, anyone seen a set of working plans for a water brake that can
consume up to say 400HP at peak (actually if I was limited to 300HP, it
would be OK for my engines' ranges). I'm not talking about something
elaborate that can be run for extended periods of time, just somethin to
run a torque curve off of for say 5 mins max. (A small doughboy for the
water reservoir would be acceptable). I'm not concerned about the water
COOLING problem, OK, just the load device.

Any leads most appreciated.

Garfield<<<<

For 400hp, you are going to need one heck of an impeller.  If you don't
mind weight, try to find a cast-off industrial impeller-type water pump
with a cast housing.  Then you would need an adjustable orifice on the
pump outlet, i.e. a gate valve of some sort.  The other requirement is
you are going to need a lot of water.  The load cell is the hard part,
but hot-rod magazines offer on-car dyno's which are torque load cells
which are mounted on prop-shafts which could easily adapted to your
driver that you mount to the input of your impeller.  Superflow dynos
are mass-produced versions of this that handle about 500hp.  We built a
stand for one of these for our Formula SAE car, and we tapped into a
fire hydrant to get the needed water.  The cost of the Superflow was
roughly $1000, if my memory is accurate.

John Bucknell is jb24 at chrysler.com