Update on two issues on the single rotor
engine.
The first issue one was mixture setting on the Rotec TB40 .
The problem is
with the reference pressure to the pressure regulator.
My mixture was to rich at
WOT to the point where the engine would just
barely run.
I emailed the guy at Rotec asking what
to do adjust the pressure regulator to my needs. The answer was that
I
should find a place in the intake system for the reference pressure
pick up where the mixture turns out to be right.
To make a long story
short, I ended up calculating the pressure situation in the TB40
and
determined that the reference pressure was way too high. The
second
position I tested resulted in a mixture setting I can live with.
In addition, I now
have also an 18” tuned intake tube.
The
second issue is a persistent oil spill through the crank case breather
tube.
I have observed this on the test stand
engine as well as on the engine in the airplane.
I just could not
believe it was rotor seal blow by, because the two
engines are not
totally identical as far a rotor sealing is concerned.
One possible
cause I found is two holes in the 12A housings exhaust port, which are
more or
less open into the oil pan. I never payed any attention to
those.
Today I did a test on the test stand engine measuring crank case
pressure under different
conditions. At 5500 RPM the pressure in
the crank case is 1.5psi, this is with the
crank case breather
open.
The next test with the crank case breather closed resulted in the
same pressure reading.
The pressure I saw can not result from blow-by
because it should have been
higher with the crank case breather
closed.
The next step is engine tear down and see what I can find.
Hopefully closing off the two holes will
solve the problem.
Richard
Sohn
N2071U
http://www.fairpoint.net/~res12/home.html