snips..

I understand there is a pusher in Fla. with a 13b

that uses a combination alternator, vacuum pump off of
a  chevette diesel engine (izusu?) I haven't checked
into it yet, but it might be a good way to reduce
weight.   Comments?  Jim Coffman

That sounds like Greg Richter's Cozy according to Chrissi it failed.
At OSH he had a aircraft vacuum pump on there and that failed on
the way up.

Paul Lamar

My personal experience using aircraft vacuum pumps with the 13B was
unsatisfactory.  The small  aircraft engine vacuum pump is not designed

for

operation higher than around 3600 rpm - maybe 4000 rpm for limited

amount of

time.  I found that when I had the pulley sized so that it provided

adequate

vacuum at low rpm (below 3000 engine rpm) the pump was soon  worn out

and

graphite dust at the higher engine rpms.  When I increased the size of

the

drive pulley so that the vacuum pump lived at engine speeds of 5500-6000
rpm, it did not produce adequate vacuum at low engine rpms.

I went through two aircraft vacuum pumps in six months and decided to go
with the Mazda smog pump even though it was heavier.  I have found it

works

fine - just damn heavy. Perhaps someone else who has tried aircraft

vacuum

pumps has a success story.  Lets hear from you.

Ed Anderson

Hi Ed,
My ex. Lyc. vac. pump driven by a toothed belt slower than it would run
normaly has done 62hrs so far. No evidence of black carbon on the outlet. My
engine idles at 2000RPM. (Slower on landing, for a bit of extra drag.)
Ian RV6A

Great Ian. Send us pictures and/or drawings of the mounting block and
aux shaft. Are you interested in making more and selling the adapter?

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