[NSRCA-discussion] Trim Change

[J N Hiller]

Yesterday I was trying to get a few flights between thunder storms and
experienced abnormal elevator trim change.
I hadn't flown this airplane for about a month but it has been totally
reliable and predictable. My first flight was cut short due to repeated
fly-overs by a full size helicopter. I got an uninterrupted second flight
with only a beep or two of up elevator trim, which isn't excessive in
changing weather conditions. The third flight I had to add about three more
beeps of up trim and I thought the air was really getting thin. The fourth
flight needed about six more beeps of up trim but the airplane acted normal
so I continued. After landing I noticed the rudder was offset about 1/4", no
wonder the flight was a little screwy.
This airplane has a tight, full pull-pull cable system that never changes
mechanically. I had a centering offset of about ten beeps on both the
elevator and rudder servos and was changing the idle trim more than normal.
You electric guys can laugh now. The fuel tank stopped had loosened and
everything in the fuselage was wet probably all the way to the tail post.
The inside of the airplane is a mess and I will be flying the other airplane
in Redmond OR this weekend.
The receiver had a little oil on one corner of the case but appears to be
dry inside and doesn't even smell like fuel. I suspect the centering change
resulted from fuel getting into the servo pots. I'm reluctant to get into
them that deep and will probably just scrap them. After three seasons they
were due for replacement anyway.
Jim Hiller