Mark Steitle wrote:

Paul,
I find it interesting that the vacuum pump has failed this early in its expected life.  An earlier picture of Greg's engine installation showed his alternator driven vacuum pump.  I liked the idea so much that I contacted Greg regarding his arrangement and got the specifics on them.  (The alternator is from a 1985 Chevette Diesel or Izusu diesel).  After thinking about it for a while I was concerned about the speed this arrangement would be turning the vacuum pump.  If you have a 6" main pulley, a 3" alternator pulley, and cruise at 5500 rpm, then the vacuum pump would be spinning at 11,000 rpm.  I don't know what the maximum rpm that these vacuum pumps are limited, but I read in Aircraft Spruce the operating range on one brand was 1400 - 4000.  I figured I would e-mail Greg after his system had a chance to live (or die) in the real world for a while to see if this was a reliable approach.   Do you know if he reduced the ratio?  Would a ratio of 1:1 spin the alternator fast !

enough

to enable the it to put out max rated amps?  It seems to me that these two accessories are at odds with each other.  -- Mark

Greg told me he worked out the RPM and is using a small racing beat
pulley on the e-shaft. We discussed it and he did not think it was caused
by over speed. My feeling it is better to go with the automotive
pump that was installed on the back of the diesel alternator to begin with.

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org