Sent: Sunday, May 09, 2004 10:53 AM
Subject: [FlyRotary] Re: first flight
Tracy's old prop.
Great flight report Rusty. You sound a little
disappointed.
I AM disappointed in the current
performance. My friends RV-3 with a 160 HP Lycoming is
nearly doubling my climb rate, with an almost identical prop. At
least I have proof that my engine isn't producing the power that Tracy's
is, so I just need to get to work on finding out why.
Hey, Rusty, if it were easy, everyone would be doing it
{:>)
Step one will be a simple thing, changing
plugs. I now have about 30 or so hours on the engine, mostly with 100
LL. I've felt a couple of times in the last two runs, where full
throttle seemed to go over rich, and leaning the mixture a little seemed
to help. I'm wondering if this might be Ed's plug
sag???
I get approx 30 hours on a set of plugs while runing 100LL
before the SAG shows up. It starts with just one or two occurances of a
flight and frequently only on one rotor and proceeds to increase in
frequency. My indications are a drop in rpm and one (or both) of my EGT
gauges will show an approx 250-300F decrease. This would normally only
last for a minute or so, sometimes changing the mixture would kick it out of
the SAG.
Step two will be a new intake, but I'm
completely undecided as to how I'll proceed.
Ed, you may not have a direct answer to
this, but how about taking a SWAG. How
much rpm would you expect to gain by going from
a typical short intake, to a fairly well tuned intake? Are we
talking hundreds, or maybe 50?
Since Tracy and I had
identical props by the same maker 68/72 and the same model engine 90 Turbo II,
both with high compression rotors, we were about as identical as could get on
engine/prop. Oh, yes, our intake systems were very similar although not
identical. We both would get a nominal 5200 rpm static (on cold mornings
due to the EDDIE effect my static would go as high as 5600-5800 rpm).
In my 120 mph (TAS) WOT climbout I normally would get from 5600-5800
(depending on OAT). So if you are not getting at least 5000 static, you
have some tuning to do.
Thanks for the vote of confidence,
but the problem is that I'll be obsessed with making this perform better, and
I'll spend all my time working on it, and not flying it. This isn't bad,
since I need something to tinker with, but it sure won't get the test hours
flown off anytime soon.
Hey, if I has spent my time flying instead of
tinkering with the engine, I would have over 1000 hours but not nearly as much
fun {:>). Think of all the gas money you save.
Ed Anderson