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Message
Greetings,
I made a couple more
flights today, and have a few comments about the rev-2 configuration.
The best news is that I
haven't had one single leak, loose bolt, or other issue with the new
configuration. I'm actually comfortable enough to venture away from the
airport now.
The other best news is that
cooling is a complete non-issue. With 82 F ambient temps, I couldn't
overheat the water or oil if I tried. The highest I've seen oil is 180 F,
and water was maybe 160 F. I'm still running distilled water, so when I
add some coolant, it will probably heat up a little. It will also get
about 20 degrees hotter in the next couple months, so that won't help
either. I'm willing to bet that cooling will still work well enough to
install the cowl cheek extensions.
More good news- the
handling is much better now that that 42 lbs is gone from the nose. It
actually flies like an RV, and stall speed is down a few MPH as
well.
I've got all the wheel pant
brackets installed now, but haven't installed the wheel pants yet.
I'm certain that the pants, and gear fairings will make a
large difference in speed (15-20 mph), and perhaps even climb. I also
need to install the gear leg stiffeners due to some shimmy that I'm
having. Currently, the speed is 170 mph TAS at full throttle, regardless
of prop pitch it seems. This is as fast as it ever was before, so the lack
of a turbo doesn't seem to be hurting me here. At 13 degrees, the rpm is
6700, and at 15 degrees, the rpm is 6200. Once I get the airframe cleaned
up, I'll feed the numbers to Warp Drive, and let them taper the
blades. They claim the tapering will add about 4 degrees of effective
pitch to high speed, but have virtually no effect on climb. I've
actually read comments by owners who say this is really true, and that it acts
almost like a CS prop. We shall
see.
The worst news is probably
climb performance. The best I can manage now is 1500 fpm, which is still
at only 100 mph. I'm hoping the wheel pants and fairings will improve
this, and put it back in the 120 mph range where you would expect it to
be. Either way, it's unlikely that I'll ever make it back to 2700 fpm like
it was with the turbo. It does appear that the turbo was pulling it's own
weight, but I'm still happy to be rid of it. This is another area
where the prop pitch baffles me. You would think that reducing pitch,
and increasing rpm would help climb, but that just isn't the case. At 13
degrees, the best climb was 1000 fpm, at 5400 rpm, and 100 mph. At 15
degrees, best climb is 1500 fpm, at 5100 rpm, and 100 mph. I just
do NOT understand this, but it also happened back with the
turbo. Is it possible that this is just something goofy about
the Warp Drive prop? I want to run the engine at higher rpms,
but neither speed, nor climb improves. Am I losing all the extra
power on the prop?
Finally (I heard that sigh
of relief), I'm not convinced that the long intake runners are causing me any
real harm (another sigh of relief heard from Paul). Throttle response is
not that bad, and I've been monitoring the temp of
the runners. So far, the temp has remained right around
ambient. The only thing I'm wondering about are some high EGT's.
This was something that was mentioned as a result of this long intake
scheme, and I can easily exceed 1800 degrees. Which brings me to a
question:
I'm running along at normal
mixture, and settle into a cruise configuration. When I start to lean
the mixture, EGT's go immediately up to 1800 plus degrees (about 10 inches
from the port). This trips the alarm that Tracy had pre-set in
the EM-2, and I richened it back up. What should I shoot for on
leaning the rotary? Is there a rule of thumb such as X number of degrees
on the rich side of peak EGT?
Thanks for any
comments.
Cheers,
Rusty (driving to Cleveland
all day tomorrow)
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