"Kyle Boatright" wrote in message
...
Any idea of what your passengers were doing at the time. In my airplane
(an
RV-6) there is a noticable change in the tone and volume of cockpit noise
(and vibration) either the pilot or passenger shifts his/her feet on the
floor.

No, no idea. But I've never experienced anything like that before, and I
have often flown with passengers over the years.

The one "passenger-induced emergency" in my airplane I'm aware of is that
the front seat passenger can actually push on the yoke lever with their
feet. Oddly enough, the one passenger to show this to me (unintentionally,
of course) was the same one that a few years earlier kept messing with my
elevator trim on a nighttime flight, by repeatedly alternating the position
of his seat back (it was a clear night, he was in the back seat in a 182RG,
and he kept lowering the seat back so that he could look at the stars, and
then raising it again to look out the side and front).

One other thing to consider is a stuck valve. Your description sounds
similar to my understanding of the symptoms of a stuck valve.

Unfortunately, that's the best conclusion I've been able to come to as well.
I've never experienced a stuck valve with this engine, so I don't know what
sort of power loss to expect. I'd *think* it'd be more significant than
what I noticed, but I don't really know.

The engine just got all new exhaust valves and guides a few years ago, so if
it's an exhaust valve problem, I'll be sorely disappointed. I suppose it
could be an intake valve problem, even though they don't get the kind of
wear and tear the exhaust valves do.

Pete