The Cessna 120-140 Association Forum

New 140 owner and was curious about trim settings. My plane has no factory appearing markings just a needle. Someone has scratched three lines on the housing. Does anybody have information on how they came originally? I noted in the POH it says to set to takeoff trim, was that a setting with markings or just trimmed the way the pilot wanted it.
Thanks

Takeoff trim is neutral, that is, trim tab is set in line with elevator surface. Typically this is marked with decals on the trim housing. Yours must have worn off. I set mine so that at takeoff the plane trims to about a 75-80 mph climb at full power hands off and have marked that with a sharpie pen (roughly neutral). Others may have different opinions

6352 wrote: ↑Fri Jul 05, 2019 8:08 am Takeoff trim is neutral, that is, trim tab is set in line with elevator surface. Typically this is marked with decals on the trim housing. Yours must have worn off. I set mine so that at takeoff the plane trims to about a 75-80 mph climb at full power hands off and have marked that with a sharpie pen (roughly neutral). Others may have different opinions

Agree. You have to check out how the trim effects the airplane while you're flying it. What may be okay for you may not be okay for someone else.

Going from memory here. Takeoff trim is somewhere between 1/4 and 1/3 of the way back from full nose down trim, if your tab is correctly rigged.

When I got my 140, there were two hand painted marks probably about an inch apart and toward the forward portion of the trim range. Halfway between these marks is the neutral trim position I use for take off. When I approach, I pull the throttle back all the way and trim for 70MPH. This position turns out to be considerably aft of the rearward hand painted mark.

Not long after I got comfortable in the plane, I went up with only myself and about 3/4 load of full fuel and got some altitude. I cut the power to idle and trimmed for best glide speed. I landed without changing trim and marked that trim setting with a piece of red pinstripe tape. That is my trim setting for a dead engine, which would probably be adjusted slightly if I ever were actually gliding it in for an emergency. That is about the same trim setting I end up with when I trim for 70 when landing.

I hope the above mish-mash is somehow helpful.

Part of my pre take off check I run it full forward then 3 turns back. Works for me and most loading situations in my plane. FWIW

Mine is worn off too... I'm redoing the interior currently... Wondering if there is a source for a new "sticker"? for the trim wheel?

Ray

I just checked the member's only section. There is a template in the library for printing a trim wheel decal, but it hasn't been activated on the new site as of yet. Rob is no doubt working on getting the template loaded from the old members site to the new one. Stay tuned.

I had my elevators re-skinned with brand new ones. They look great. For a reason we don't understand, the trim up and down degrees were completely off when we re-assembled. We spent a few hours demystifying the mecanism. Thanks to John for some advice. Think it was another thread. We had to slack the whole trim under the stab to remove the chain from the sprocket, then align the red arrow on the trim wheel to the position (either full nose up or down) and adjust the trim pushrod accordingly to get the 33deg down and 6deg up. You may have to slack the block stoppers on the trim cables to achieve all this. Always fun to crawl inside the fuselage

Test flew today and works great.
Attached is the TRIM decals I recreated for myself using the template that I think was available in the member section.
Use and modify to your needs. It includes the operation placard and baggage placard. The narrow up+down decal fit just ok beside the trim wheel.
Enjoy!

Mine must be worn off as well. I used a sharpie and put a mark at neutral. I find I only use trim for take-off, climb, and level flight, and long decent. I really don't use any nose-up trim for landing in the 140. I find the back pressure required to hold the nose-up and the plane on speed in a pattern decent is minimal. Now, in the 185 I'm usually full aft trim when landing if no load is in the back.