----- Original Message -----
Sent: Wednesday, February 16, 2005 6:26
PM
Subject: [FlyRotary] I found the
power
Today I finished installing the firesleeve on the
remaing fuel lines, made some stand-offs so that the fuel lines would not be
right up against the engine, and finished hooking up and securing a few other
items. With the top cowling off, I ran the pumps for a minute, then
checked for leaks...none found. Then I started the engine and ran it for
20 or so seconds and shut it down and reinspected for fuel leaks. None
found. I restarted and taxiied away from the hangar a bit so as to not
be as loud for others in and near the hangar and did a full power runup.
I hit 5600 static rpm's. In the past, the best I could hope for was 5200, most
of the time settling for 5100 rpm's. I taxiied back in and installed the
top cowling....max rpm's 5100. Took the top cowling back off....max
rpm's 5600. One more try....5100 with the cowling back on. It is
beginning to become more clear to me, that one of two things are affecting
rpm's. Option one is that with the top cowling on the engine is
ingesting heated air and just cannot develop the same power as when it ingests
outside unheated air. Option two is the muffler bearing may be
worn. I'm kinda leaning toward option one.
I was thinking of
installing two small NACA ducts on the bottom of my cowling with two hoses
coming up to feed air to my TWM throttlebody. The NACA ducts I purchased
from Van's RV (made for cowling ventilation) already have a male outlet
already molded in the assembly, so you just slide a hose over it and secure
with a clamp. Very simple installation.(Works well for my cabin
ventillation) If I recall correctly, they are about the same size as my
throttle body bore. I wonder if I will loose much efficiency as the air goes
through the corregated hose, and if the Van's RV ventillation NACA ducts will
provide a sufficient volume of air. Of course while flying, I would have the
advantage of a little bit of ram effect as well as the ability to suck in
fresh outside air that has not been heated inside the cowling during
taxi/takeoff run. Any opinions/suggestions would of course be much
appreciated. I will discuss the vapor lock issue in the next post, so as
to not complicate responses, etc. Thanks to all who reply. Paul
Conner
No virus found in this outgoing message.
Checked by AVG
Anti-Virus.
Version: 7.0.300 / Virus Database: 265.8.8 - Release Date:
2/14/2005
>> Homepage:
http://www.flyrotary.com/
>> Archive:
http://lancaironline.net/lists/flyrotary/List.html