Hello all,
I am reworking my Dynon pitch servo installation. Having installed the servo as
a retrofit, I chose the tunnel bulkhead (just aft of the Monowheel opening)
as the mounting location. The servo is oriented vertically on the bulkhead with
the push-pull rod pointed aft and connected directly to the pitch tube.
Unfortunately, the installation has performed poorly, with the pitch servo
unable
to hold altitude. With the plane trimmed out prior to engaging the AP she
flys steady hands off. As soon as I engage the autopilot it start hunting with
huge altitude excursion ensuing.
I talked with Dynon at SNF, and they suggested I check for play in the push-pull
linkage and pitch tube control linkage. While I dont have any play in the
system,
I did find that the tunnel bulkhead was flexing, which essentially has
the same affect. This was surprising as the bulkhead is 3mm plywood with
fiberglass
on both sides.
So, I am fabricating a new bulk made from a 1/4 foam core with carbon fiber on
both sides. Boy is this stuff rigid. I am also adding a couple of stiffeners
which is probably overkill.
Well, more to come,
Erich
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