----- Original Message -----
Sent: Monday, February 07, 2005 8:47
PM
Subject: [FlyRotary] Re: Bad day at the
airport
Paul, as they say - a good landing is if
you wall away from it - an excellent landing is when the aircraft will fly
again without repair and an Outstanding landing is all of the above but, you
don't leave skid marks on the taxiway. Certainly glad everything ended
as well as it did - good thinking and decision making under a bundle of stress
- I know, I have left skid marks for 300ft after aborting a take off,
ended up 12 ft off in the grass.
Here is a wild guess at what could have
caused your problem. I would wager that you did not reprogram the map
after putting on the smaller dia prop. My aborted take off occurred
because I had been tuning the ECU (not Tracy's EC2 - an aftermarket auto unit)
with a Laptop - but, of course I could not tune the map for those rpms above
static until I got airborne. So on the ground, I extrapolated for
the higher rpms figuring to refine them in the air. As soon as I lifted
off and had gained approx 20-30 ft of altitude, the engine revved into the
part of the rpm range that I had extrapolated the Map settings. The
engine immediately dropped from 5000+ rpm to around 3500 rpm, recovered and
surged back to 5000 then died back down to 3500. Despite being airport
and 80MPH I elected to abort on this 2200 ft runway. Touched down firmly
300ft from the end (measure the tire tracks) got on the binders very hard (you
know what I mean - glad I had the nose wheel) and left rubber (actually no
skids - no flat spots of tires) just rubber digging into the tarmac from point
of touch down to rolling off the grass. I remember dodging between two
end of runway light markers so I wouldn't ding my flaps. Funny what you
think of at times like that..Now, in my case if I had just had the time to
reach over an play with the mixture control I might have found that full rich
would have enabled flight - or if I had taken one more fraction of a second in
making a decision I truly could have been in bottom of a ravine at the
end of the runway.
But, the point of my tale is I suspect that one
possible cause might be your engine getting into a higher rpm region of your
fuel map which you perhaps couldn't get to with the larger prop. If so?
(and a big IF I admit), then if it were too lean the engine would lose
power. In any case, a hearty pat on the back for handling a very
challenging situation with cool aplomb (well, hell nobody was with you to say
otherwise {:>)
Best Regards
Ed
Hi, Ed...
I considered that as a possibility...no, more
like a probablility....but I was thinking that when I reduced the throttle the
engine rpm's would have gotten back into the area where it was programmed
correctly (or at least closer to correct). I throttled all the way back
to 1/4 throttle, and then back to 1/2 throttle, and no improvement. It was
difficult to reduce the throttle on an already "not climbing" aircraft, but at
that point, I was willing to try anything. Could not get it to go above 2000
rpm's, and it was running VERY rough. Paul Conner
----- Original Message -----
Sent: Monday, February 07, 2005 9:09
PM
Subject: [FlyRotary] Bad day at the
airport
On Sunday I decided to do a little "tweaking"
on the ECU fuel mixtures on my 13b powered SQ2000. I had the larger 3
bladed Performance prop on, and just wasn't getting the rpm's I wanted, so I
put the smaller dia/less pitch prop on and took it to the end of the runway
and once I was lined up on the runway, advanced the throttle to wide open.
RPM's were only around 5100, but I have flown it that way before, so I
decided to go ahead and try to work with the mixture programming at 5000
feet. Acceleration was normal, liftoff in less than 2000 feet, and
started my climb. At approximately 250 feet, the engine started failing
rapidly. I tried various throttle positions, with no improvement. Unable to
maintain altitude. I immediately started a left turn, hoping maybe the
engine would recover enough to just get me to 500 feet downwind so I would
have a chance of making the runway. No such luck. I was now heading
back toward the center of the airport at approximately 100 feet and
descending. I wanted to land on the center turn-off section in the
middle of the airport, but that would have me landing straight towards
several parked aircraft and the main hangar. Not the best
option. There is a newly paved area slightly to my left, where
aircraft may be tied down in the future, but it was empty for now. I was out
of options and altitude. I crossed the runway at less than 50 feet. I didn't
want to land going across the runway, because the grass and mud I would
encounter after rolling across the runway would probably flip the aircraft
over. I headed for the new aircraft tie-down area, and attacked it at a
45 degree angle to get as much "runway" as possible. I held it
off until I was over the parallel taxiway, and landed on the parallel
taxiway (the short way, of course) and with heavy braking, began skidding
across the aircraft tie-down area. (See attached photos). I knew I
couldn't stop in that short a distance, but hopefully when I went off the
other end of the pavement, I would not be going as fast. The nose was
dipped down at an angle from all the heavy braking, so I had a nice view of
what was coming. Grass, mud and a ditch. The aircraft kept slowing
down, and as I ran out of pavement, I wasn't going all that fast. I probably
only went 10 feet past the end of the paved area into the grass and came to
a stop. Missed the ditch by almost 5 feet !!! No problem...that
was fun !!! Just don't care to do it again. I restarted the engine and
taxiied back to the hangar, pretending nothing had happened. I don't know
what to do at this point. I don't care to have this much fun again
anytime soon. I'm torn between a carburetor and a Cessna. Paul
Conner
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