Well, it has happened. The airplane has itself demonstrated its capability for
safety by having an engine failure - a slow motion failure. I was climbing out
on the usual profile that provides an easy glide back to the departure airport,
when I heard a sound change. It was enough to look over at the manifold pressure
gauge to see 30 inches, when it is normally 36 inches in the cruise climb.
I throttled back and then increased power to confirm the 30 inches was not
a hallucination. I checked the fuel flow to see if there might be some sort of
fuel leak - a hazardous condition to be sure. The fuel flow was normal, so I
throttled back to idle and returned to the airport. I considered shutting down
and feathering, but it was running OK at idle, so I didn't. The airplane arrived
over the field at 3500 agl. A circle followed with full speed brakes, with
a high downwind leg. On downwind, the engine started to vibrate in a quite
pronounced
manner, so with the field made, I shut it down , leaving it to windmill.
The vibration stopped as soon as I turned off the ignition, throttle at idle.
The airplane lands the same way regardless of the power - engine at idle or shut
down. The landing was normal and I just took the high speed exit, coasting to
a stop. By that time, the airport people were out there with their trucks and
flashing lights (un-invited). A brief look over the airplane showed nothing
obvious and a peek in the engine cowl showed nothing obvious either. I tried to
restart, but it would not start so it was towed to the hangar (by my Dad, who
had just arrived in his airplane).
The problem turned out to be a very simple one - yet a show stopper. The engine
has two carburetors which are held to the intake manifold via rubber flanges.
It is really quite a Mickey mouse design that I will be doing something about
in the future - a back-up to keep this from resulting in a non running - or
rough
running engine. The rubber flange on the left side of the engine cracked
and split 180 degrees, causing the carburetor to separate enough from the intake
to let in enough air to essentially kill the two cylinders on the port side
of the engine. The fix would take about 10 minutes, if I had the $75 part that
has already been ordered. The glider wings paid off making this thing a very
easy and almost relaxing event. The only hiccup was a Cessna taking the runway
when I was abeam the numbers on downwind announcing what was going on. Some
people's kids???
To quote Forrest Gump "That's all I have to say about that!"
Dave
A227
mini U2
215 hours TT
I'll probably attach the picture of the flange to the Mini U2 web site.....
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