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Thanks for sharing that information, Ed...I am
going to try both leaning and richening (on the ground) to try to get my static
rpm's higher. Probably a simple thing to do once I know for certain the
direction to go. I didn't notice any surging of the engine.....Just that
after 1/2 throttle, the more I would advance the throttle, the slower the engine
would turn. (Exact opposite of what the throttle was doing) and if you continued
towards full throttle, the engine probably would have quit.
Glad to be in a club
with such accomplished designers/builders. Hopefully we will help further
the momentum of the rotary installation. More successful flying rotaries
will probably entice others to follow, and the more that follow, the more
valuable ideas and information we will all reap the benefits of. Take
care, and thanks for the info!!! Paul, need more power,
Conner
----- Original Message -----
Sent: Sunday, December 12, 2004 6:57
AM
Subject: [FlyRotary] Re: DAR visit?
Congratulations, Paul. A first flight to
remember as most are. Good to see sound decisions and judgement
exercised when faced with problems.
4400 rpm is a tad on the low side for
the engine to produce good power. My calculations indicate that if
you were at the best power A/F setting you were producing approx 138
HP.
Not familiar with the microtech ECU, however, its
been my experience that if you are overly lean, the engine will surge.
Rpm will increase up into the "lean" region where it will be unable to produce
power to sustain that rpm upon which rpm will decrease until it gets down into
a "richer" region of operation. There it will have the power to produce
power and once again the rpm will start to increase, repeat, repeat,
etc.
My engine bogs (depending on exactly what you
mean by that) when there is too much fuel. So your diagnose may be
correct - rather than overly lean it could be overly rich. But I
have found the rotary can run considerably overly rich before
bogging.
Just wanted convey these thoughts to you as you
trouble shoot. Sounds like you have your temps OK, but remember you were
probably not producing what you would like in terms of power. Temps will go up
as power does.
Again, its great having you in the air, welcome
to the club.
Ed
----- Original Message -----
Sent: Saturday, December 11, 2004 6:22
PM
Subject: [FlyRotary] Re: DAR
visit?
----- Original Message -----
Sent: Saturday, December 11, 2004
11:40 AM
Subject: [FlyRotary] Re: DAR
visit?
Hi, Rusty....yep....airworthiness
certificate in hand.
Congrats!
Not looking like the greatest choice of wind at your
airport today. I just checked the wx for the area, and find a 15kt
gusting to 22kt, which is almost a direct crosswind from the left.
Should ease up this afternoon, and be much better tomorrow.
With that kind of left crosswind, coupled with my ample left torque, I'd
never be able to take off :-)
Cheers,
Rusty (more bite than
bark)
You're correct, Rusty....the winds were a direct
crosswind 20 knots, gusting higher (windsock standing straight out).
At approximately 3:30 P.M. my SQ2000 slipped the surly bounds of
Earth....made a couple circuits around the airport and had an uneventful
(yawn) landing. The precarious part was the take-off and
climbout. I am not getting enough power. From 1/4 to 1/2
throttle, engine accelerates smoothly and plenty of power. As soon as I
try to go above 1/2 throttle, the engine begins to bog down. Advancing the
throttle more only made it bog down even more. On takeoff roll, I
was only able to get 4400 rpm's at approximately 1/2 throttle.
Acceleration felt OK, and the nosewheel lifted at around 70 knots. Mains
lifted off shortly afterward, but it just didn't want to climb. (Flew fine
in ground effect, of course). Unfortunately, I had reached the point
of no return (short runway) and past the accelerate/stop point, so I was
committed. Found a "V" in the treeline and headed for that.
Made it...(whew)....continued slow climb to 2000 feet, made a couple of
circuits around the airport and had a smooth landing (considering the
strong, gusty crosswinds). Down and stopped by mid field.
I had a few "bugs" to
work out, like tightening the tension on the nosewheel, so after 3 trips
to the runway and back to the hangar, by the time I got to the
runway the fourth time, water temperatures were up to 190 degrees.
Fortunately, on climbout they started dropping, and by the time I was
downwind, they were stable at 170. I am pleased that the temperature
decreased in the climb.
I have to work on the
power problem ASAP. I'm thinking it is mixture related. I had
programed the MicroTech ECU to be 10 percent leaner (for all throttle
settings), and perhaps that was a mistake. If I remember correctly,
you need sufficient air and sufficient fuel to make power. Because
the butterfly in the throttlebody continues opening past 1/2 throttle, I'm
reaonably certain that I am getting more air past 1/2 throttle. I am
assuming that I am not getting more fuel coming in past that 1/2 throttle
position, causing the engine to bog down past 1/2 throttle. Best RPM
I could obtain was 4400 rpm (in cruise with the prop unloaded), and with a
2.19:1 gear reduction,that puts my max rpm on the prop at only 2000.
Barely enough to fly, let alone climb out. Will continue problem solving
and pass on results. On the positive side, first flight was
successful, aircraft flew well, and no-one got hurt. I have to count
that as a success. Take care. Paul Conner, Mobile,
AL
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