Good to hear the progress after all your
trials and tribulations, Chris.
Yes, do not idle too low an rpm. The RWS
PSRU has a torsion resonant frequency at lower rpm – also with light
rotating mass from the prop (unlike a heavy flywheel), a higher idle reduces
likely hood of engine unexpectedly dying and provides you up the power band if
you need power in a hurry, Scotty.
I would not idle lower than 1600 rpm and
my engine normally idles between 1800 – 2000 rpm. My engine has a street
port job and this is really not radical enough porting to materially affect
idle. My engine rpm at idle gives a prop speed of 600 – 700 rpm (with my
2.85) and I really don’t want it any slower. You get more prop rpm with
a 2.17 of course.
Glad to hear you have isolated the two
coils. If you have not already, I would also do the same for the two fuel
pumps. There is simply no safety benefit to having both sets of two critical
components on the same wiring/circuit breaker lines.
You’ll be flying before long.
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Christopher Barber
Sent: Sunday, July 06, 2008 11:45
PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Saga info and
questions
I was out at the hangar again this afternoon. The
engine is starting "all but" really easy. What I mean is it is
starting within a couple of blades but I still have some issues. I think
one (or perhaps both) of my batteries is not being charged by its respective
alternator (Aeroelectric Z-14 drawing). I am getting the volt reading on
the EM2 flashing most of the time. I do not yet know why it sometimes
does and sometimes does not. One more thing to track down. I should
be able to start the troubleshooting in the next couple of days. I gotta
educate myself on proper diagnostic skills in this area.
Again, until I actually come across the issue it is only
philosophical and I have to get up to speed.
I know I have some other electrical issues. The other
day when I shut the primaries down at a higher RPM the engine stayed running on
the secondary's (or so I suppose), However, when I did so today the engine
started to die. I am also have my master and aux battery c/b still
popping (but I have not had time to really look at this yet). The engine
runs but I gotta find the reason.
Based on Ed's comment the other day I went ahead and cut
into my new coil harness and provided independent power for the leading coils
and a separate line for the trailing coils. I had wanted to do this
before, but had not done so until Ed's words screamed in my head. Now
either set of coils keep the engine alive. I get a very slight rpm drop
when on either set of coils and this is what I think should have been expected.
Thanks Ed.
I am getting some missing but I think this is getting better
as I get the mixtures tuned more properly. I have been able to get idle
as low as about 1200 rpm, even though it is pretty rough. This engine has
a medium street port and it seems I remember reading that at this port level
low end idle may suffer. Maybe it is only a more extreme port but at 1200
it is moderately rough. I have to be careful as to basing too much on
engine sound since as I move around the plane the sound changes. I think
part of this is a popping I get at certain angles due to exhaust against the
prop. I think this because as I move my head from one position to another
the tone changes. So, if I just hold my head (and tongue) just right, it
sounds much better. I will need to learn to rely on the ME, I suppose
The engine seems to like to idle better as I bring the rpm
up to 1400, 1500, 1550 and 1600 rpm it. I read in the achieves in the last few
days, IIRC, that Tracy and Ed Idle at 1600. At 1600 rpm the plane will
stay put without braking or chocks. If I bring it up to 2000 rpm it
really starts to move. Oh, did I mention I have taxied around a bit?
<yea>.
I do not seem to be getting Auto tune to function
correctly. I enter the auto tune mode and I get a lot of tall bars
jumping around, but I do not really notice any difference in the way the engine
is running. I am guessin'/hopin' I need to do more manual tuning first. I
am not confidant in my knowledge on how to read the tracking mode or auto tune
mode yet. It does make better sense as I "play" with it more
(with the manuals in one hand and knobs/throttle in the other <g>).
I am not sure of how to actually tell it is in the actual auto tune mode as the
graphs seem to change, but maybe they would have anyway. The difference
between genius and ignorance?????? Genius has its limits <g>. I am
becoming more comfortable with the EM and ECU even though I wish Tracy would include the
coolant and oil temperature in tracking/auto tune mode so I would know when I
am hitting my limits. I had a brief issue when my temps shot up to about
240 for several seconds when I went WOT and then came out of auto tune mode.
Finally for tonight anyway, when I did go to WOT, I got to
about 5500 rpm and my RPM reading on the EM2 went blank. I throttled back
a bit and the rpm readings went all over the place. I throttled back a
bit more and the readings returned to normal. This happened with my old engine
as well but the engine went belly up before I found the problem. I guess
I will have to check wires again, but I have literally checked the wires (and
replaced a few) at least 20 times. I cannot stay at these rpm's very long
at all as it is very hot and humid in Houston
in July. It is usually somewhere between 90 and 97 in the afternoon when
I am out at the hangar. SO I AM ASSUMING THAT my temps are not all that
bad considering the high heat on a stationary bird.......PLEASE correct me
where I am wrong. What should I be seeing. I wish there was a truly
one stop source for all this basic stuff, temp, expected rpm under certain
conditions. I seem to have seen it all at one time, but still find myself
hunting for it online and/or in Tracy's
material.
I still feel like progress is being made and most of this is
pains of success. Yeah, that's it ;-)
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