Here is the strange series of fortunate events:
Yesterday: Finish removing the waste gate flapper (making the waste
gate wide open). Install an aftermarket racing muffler (easy, light
weight, works pretty well – may not last), and finish installing new
tires and wheel pants with fresh coat of primer. Fix oil leak at
redrive exit, and small coolant leak. Remove Evans coolant and put
wetted water back in.
Ground engine run, all is well.
Brief flight around the pattern, performing and cooling very well.
Fly 20 miles from MFY to CRQ near my house (saving 1.5 hrs of driving in
traffic) – (they are removing GA from all the local airports and NOTHING
is available there and the are not taking any names): On start-up
engine running rough, switch to computer B fixes problem (frequent
occurrence of rough running on computer A when engine warm that I
attribute to heat soak of the manifold temp sensor – runs normally after
take off). Fly to CRQ on computer B (forgot to change back to computer
A) with great performance and cooling – land an taxi on computer B.
Today: Arrive at airport with wife, load plane for trip to mountains.
Start on computer A and taxi out. Switch to computer B during run-up
and it sounds like it is running on one rotor, but normal on computer A.
Tried change in mixture, cold start, and lead/trail tests, mixture
variance without change. Dang!
Taxied back to parking on controller A which was working perfectly. The
only thing I could think of which would make one computer work but not
the other was the MAP tubing…. which was intact on inspection. Tried
it again turning off all avionics – no change.
I called Tracy and discussed the issue – leading culprit seemed to be
the primary injector actuator of one of the rotors for the computer B.
Time to call in Fed-ex before Tracy leaves for Oshkosh.
BUT, I am away from my hangar in 95+ heat with no tools or shade…. Then
someone offers some shade and says throw on that cowl and taxi over, so
I do (foreshadowing #1).
FORTUNATE EVENT #1: So, because my engine sounds so strange all the old
guys are stopping over for a chat and to see if they can help… I need
a hangar at this airport I say, and low and behold within 2 hours I am
paying for my new hangar. Never mind that I am going to be paying
$625/mo for a tiny t-hangar with no power and the locks don't work!! I
am still glad to have something near my house. – hand over the check…
So I decide to taxi over to my hangar. On accident, I start it on
computer B AND IT WORKS!!! WTF???? Now everything is working as
normal… unlikely a failed component in the EC2.. Hmmmm
So we go to lunch and I think about it… Wife says that it sounded
really funny from the outside on the last engine start, kind of like a
gear-box noise (foreshadow #2). "That's OK" I say, "the new muffler is
just allowing you to hear the non-engine noises better". Finally decide
to go back and try it again.. Start it up an everything seems OK on
both computers.. why not take it once around the pattern or something?…
Get ATIS, talk to ground, taxi, wait my turn, position and hold, cleared
for take off, throttle forward and suddenly remember the cowl is only
thrown on… no pins in place! Idiot!! (Fortunate events #2 and #3).
Abort, no issue, taxi back is normal, shutdown is particularly smooth –
no rattle like usual – must be the new muffler (foreshadow #3).
I put the plane in it's estate (after all it must be an estate for that
price), and another old guy comes over. Sounds funny.. yea yea… Show
him the engine, pull the prop through a couple times… wait, that feels
funny…
HEY! The flywheel is barely turning as I turn the prop… Oh there it
goes, the prop is totally freewheeling!!!
It was the luckiest bad day I ever had. My RD-1B is clearly broke,
completely. Last inspection was less than 10 hours ago, no issues.
When computer B was not working sometimes it would give a backfire and
it was running VERY rough. Maybe that was the cause. Maybe I put it
back together wrong after the last inspection…
Tomorrow I will go get my tools and close out my old hangar. Take off
the RD-1B and EC2. Send both back for inspection and upgrades…..
I guess there will be no flying this vacation, but that's OK because I
still have a plane and my skin….
Luckiest Bad Day I ever had…
Dave Leonard
Turbo Rotary RV-6 N4VY
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