Trim Position Setting

[Warren Janzen]

I have a 180 Comanche. While flying full tanks and just myself at
75% power, I noticed the trim position seems quite forward. Later
with a copilot along similar position. I might have 20 pounds in the baggage
compartment. Trim position at neutral for take off seemed normal.
See photo. Any advise?

[LeWayne Garrison]

The trim drum in the tail cone can be adjusted to give more available nose down trim. With that done, the trim indicator will move rearward and give you more adjustment in the trim.

[Larry Martin]

I am noticing forward trim more forward of what I would have expected on a -30. Is there a "relative" position that one should expect prior to going through the expense of redoing the trim drum winding?

[LeWayne Garrison]

In cruise the trim setting should be near the neutral range when the aircraft is loaded approximately at gross weight and in balance. The trim drum is easily accessible by removing the tail cone. The adjustment itself is also straightforward and should take no more than 30 minutes. All told, removing tailcone, adjustment and reinstalling tailcone, about 1 hr to 1.5 hours. Good time to lube everything back there anyway.

[Larry Martin]

Thanks LeWayne,

I'll check that out. I have a service manual and will follow the proceedure if the trim is out in cruise.

[Zach Grant L1011jock]

The faster you go, the more forward the trim will be. You trim for a speed, so the faster airplanes will see the trim indicator show more forward trim settings in cruise and descent. The trim indicator is a separate lever arm and single cable that has a spring At the other end and shows actual trim linkage position. It is separate from the trim cable that goes around the crank and trim drum. Think about it this way. If neutral trim is good for takeoff and initial climb of about 100 mph, when you are cruising indicating 160+ Mph, the trim should be well forward of the neutral point! You won't run out of nose down trim if the plane is flown in the airspeed envelope and in CG unless something wrong. 180s show closer to neutral in cruise, twins show the most forward.

Zach

[Clarence Beintema]

If you have a manual go through the procedure first and understand what is involved. You will need to build the stabilator rigging tool from the dimensions in the manual.

The basics are set the stabilator in the correct neutral position, set the trim drum in the correct neutral position and set the trim tab in the correct neutral position, set the trim position indicator in the correct neutral position.

Clarence