Charles Wilhite wrote:

snips....

Water pumps can be underdriven as long as the time at idle is
minimized.  Drag racers get away with it regularly.  At higher engine
speeds the reduced pump rpm is adequate.

For some radical ideas I'm not sure I would be ready to test in the air
check out these pumps.  The Davies Craig unit is especially interesting
as it has a 2 year warranty, and has an optional variable speed
controller that maintains water temp measured in the head (or block in
our case!)

http://www.daviescraig.com.au/

http://www.meziere.com/cgi-bin/web_store.cgi?page=/index2.html&cart_id=9006042_28861

Charles

I think we have been there and done that. Automotive use is no where
near as demanding as aircraft use. Even automotive drag racing. Electric pumps 
that claim 35 GPM with tiny electric motors just don't work out in real 
aircraft life. Ray tested one and got 9 GPM and not 35 GPM as advertised. 
Looking at the motor and the size of the inlets and outlets it is obvious 
why this is the case. Perhaps over seas manufacturers are not subject to
our truth in advertising laws. 

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org