Paul,

I made a major breakthrough today. In preparation for hooking up the Hytek
data logger, I decided that it would be good to install check valves on each
vacuum line leading from each rotor housing. (For those who are unaware, I
am running a peripheral port 3-rotor with a PL slide
throttle.) My system measures MAP from the unused oil injection ports in
each rotor housing.) Not sure what possessed me to do a ground run right
then, but I ran the engine right after installing the check valves. Now keep
in mind that typical MAP readings at idle up to this point was approx. 17"
Hg. Well, today MAP readings were in the 14.4" - 15.0" Hg range.

Then it dawned on me that the way the vacuum lines were plumbed the RWS EC-2
would see an average of all three rotors. Since each rotor is 120* (crank
degrees) apart in their 4-stroke cycle, the MAP would be quite a bit
different for each rotor. By installing check valves in the vacuum lines, I
have isolated each rotor from the other two and I am measuring the lowest
vacuum. Idle is now down around 1500 rpm, but the mixture is way lean, so it
appears that a re-tune is in order. I'll probably re-set the RWS EC-2 to the
factory defaults and

start the process over from the very beginning.

We need to stress to anyone that is measuring MAP in the rotor housings to
install check valves in each of the lines.

Mark

Good work Mark. Here is the latest voltage to pressure chart.

Paul Lamar


Hey Mark,

I assume you placed a check valve at each rotor that only allows air
to flow into the rotor thus presenting the lowest pressure reading in
the manifold connecting all the check valves together.  How are you
allowing pressure to flow back into the system when you open the
throttle and increase the MAP?  Seems to me that you will read the
lowest MAP at idle but you will have no idea what happens to the MAP
after that because there is no way for the increased MAP to get past
the check


Mark LaPierre



Mark,

Yes, that could be a problem... if the check valves seal too tight.
I'm counting on a certain amount of leakage.  I haven't done enough
ground runs yet to determine if there is a problem here, but if it
is, I'll be looking for another solution to the problem of poor idle.


Mark S.
Mark S are you having any problems landing due to the poor idle?  Are
you using a 2.85:1 PSRU ratio.  I forgot if I ever knew :) I am
building a 3.12:1 box for the extra power at 8500 RPM (800 prop RPM)
so 2500 engine RPM idle should be no problem in this regard.

If you blow compressed air into the rotor housing between the exhaust
port and intake port it will idle better as it will keep the
contaminated exhaust gases out of the intake.  The path for these
gases is the depression in the rotor flank.


Paul Lamar


Mark, Your problem with poor idle is the peripheral port. You've
changed your port timing, which is just like adding a race camshaft
to a V8.  I've never made a peripheral port engine idle smooth.

Bob Mears