Chuck wrote:
Well I did not make it to Arlington. I was over the Grand Canyon at 12000 ft when the engine suddenly started shaking and RPM
dropped to 3900. Turn on the aux fuel pump, tried backup engine controller, tried disabling trailing then leading ignition,
everything looked normal but RPM. GPS reported nearest airport was Marble Canyon 21 miles away. Set up best glide, headed for
Marble Canyon, looked at EGT and rotor #1 (rear rotor in RV6, front rotor in car) was showing <400F. 12 minutes later, Marble
Canyon was 1 1/2 miles out but could not reach it so I set up approach on Highway 89A. It was looking good until a truck pulling
a travel trailer appeared from around a curve, heading right for my intended touchdown spot. He made no attemp to pull over, so
I had to stay above him. After he passed, I tried to set it down but did not have enough speed to flare so it dropped in pretty
hard. Got it slowed down and off the road, luckily there was a nice wide spot waiting for me. I got out and surveyed the
situation, the port wing had struck a highway marker post just inboard of the wingtip and ripped a 2 foot gash in the lower wing
surface. The main and tail spring gear were all slightly bent from the impact.
Later after the engine and I had cooled off, I pulled the plugs one rotor at a time, and sure enough there is no compression on
rotor #1.
My friend flew up and picked me up, we flew home, loaded up tools and trailer and made the 8 hour drive up there, removed the
wings loaded it up and headed back to Safford.
It has been an interesting couple of days. It will take a bit longer than that to repair the damage.
I will report on the engine when I get it apart.
Chuck Dunlap
Real sorry to hear that Chuck.
Thank heaven you made it OK. Congratulations on a saved-my-ass-job well done.
Also good job on the design of the motor mount as the engine would have dropped out
on the road if it had been weak.
Were those three piece apex seals?
For the new people. This is the very first failure of the basic engine that
I have heard about in the five year history of the news letter. Apex seal failure
is common on turbo engines that are subject to detonation. Apex seal
failure is rare on normally aspirated engines like Chuck's but has
been experienced in car engines with the three piece design.
They are less tolerant of high wear. The new RX8 motor has gone
back to the two piece design.
Paul Lamar
Hey Chuck,
I was looking for you at Arlington, since you were supposed to arrive
there before me. Really glad to hear there were no injuries. Can you
clarify something: did you have partial power at 3900 RPM on the way
down, extending your glide? If not, what were then conditions when the
engine quit running?
That sounds similar to an apex seal failure I had in a 1987 turbo car.
In that case it was the rear rotor. Suddenly the car lost power big
time. I could keep the engine running by keeping my foot on the gas
pedal. Managed to clutch and brake and keep the right foot on the gas
pedal for 30 miles to get me home, through stop lights and everything.
Once home and I turned off the engine, it would not start again, as I
suspected it would not.
--
Perry Mick
Custom Composite Props
mick@bridgingworlds.com
http://www.ductedfan.com
The AirCraft Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/
Copyright 1998-2003 All world wide rights reserved.