Charlie: My Alon has the trim knob between the seats trim. When I bought the plane a year-and-a-half ago, it also seemed to have a mind of its own when it came to trim. What I reasoned is that there was so much friction in my trim cable that it took a lot of buffeting, etc. to free it enough to actually move the trim tab. With the cable having the spiral outer casing and being so long, you could move the control almost from one stop to the other while the plane was on the ground and the trim tab would move very little.
What I did to cure this was to:
(1) Loosen the clamp at the trim tab.
(2) Remove the trim knob assembly so it would be easy to pull on the
cable.
(I actually took it apart, greased it, and painted the exterior, but that
is not necessary.)
(3) Find a friend and equip her with visegrips.
(4) Using LPS-1 (or your favorite anti-rust anti-moisture stuff) spray
every part of the cable you can reach (yes, I got a tail stand and crawled
inside the fuselage). The LPS1 will penetrate the cable.
(5) You and your friend alternately pull on the cable ends to free it up.
Continue to spray liberally with more LPS-1 if required.
(6) When the cable is free enough that you think that the trim system
might
work, re-mount the trim control and follow the Maintenance Manual
instructions for re-setting the trim. What's real important is to be sure
that the spring is in good condition, that the tab up-stop is at the
proper
angle, and that the tab runs through the specified angle. The spring is
especially important as it is the insurance that the tab won't flutter if
the cable clamp comes loos or the cable breaks.
This made my Alon trim really well in all conditions.
If you think the spring isn't important, hear this:
When I was a student pilot in 1965, I started my lessons in a 'coupe.
Shortly after takeoff one day the entire plane started vibrating. My
instructor had no idea whether a piece of the wood prop let go, a cylinder
quit, we had carb ice, or a structural problem. There was no indication
other than the whole plane vibrating but the controls themselves didn't
vibrate excessively. Carb heat didn't help - the only thing that helped at
all was reducing RPM. We landed and yes, the clamp had come loose.
I think that back then the 'coupe might not have used a spring - I don't
remember whether it was a two-control or three-control coupe; the school
flew both.
I changed schools because I was worried about their attitude toward
maintenance - my instructor never did a walk-around and never showed me
how
to do it.
(I wrote this up as an "I learned about-flying" back in the '60s, but it
was rejected by the magazine.)
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David Smoler | __ |
Alon A-2 #A35 |==/__ยค_\==|
N6359V *==========|==| () |==|===========*
| \____/ |
based at RHV () () ()
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At 01:14 PM 9/13/98 -0700, Charles McKinnie wrote:
>Steve:
>
>I don't know how the M-10 trim system is different from the Forney, but
it
>sounds as if it may be similar. I also have a knob between the seats.The
>Forney trims up fairly well if the air is smooth. In turbulence it is a
>different matter and it seems as if I'm constantly re-trimming. Don't
know
>if that really answers your question but that is my experience. It just
may
>be the nature of the beast.
>
>Regards
>
>Charles McKinnie
>-----Original Message-----
>From: Steve Dold <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
>Date: Saturday, September 12, 1998 9:04 PM
>Subject: Trim
>
>
>>Our airplane requires frequent re-trimming. Sometimes during a
>>cross-country it'll settle down, but more often it will be flying along
and
>>suddenly need to be re-trimmed drastically, with no change in airspeed
or
>>power. Does anyone else have this happen a lot?
>>
>>It's an M10 with the knob between the seats. Maybe the cable sticks.
>>
>>-------------------------------
>>[EMAIL PROTECTED]
>>Say NO to useless over-quoting
>>-------------------------------
>>
>
>
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