Manual Elevator Trim Question

[Sunriver Ken]

I purchased a completed RV-9A that has manual trim (screw-type). It seems very touchy so I was wondering if changes were made in later years to make it less sensitive. If yes I hope it is something simple.

Thanks

[bkilby]

It's just that sensitive... 1/4 turn will do ya. Not like a cessna where you cram that huge wheel 3 turns in each direction.

[Jerry Cochran]

Partner and I had a flying -6a during our build which had an electric trim. I thought it was hard to get a perfect trim so I installed manual trim in my own -6a. IMHO much simpler to get the trim "just right", and when I build the next one it too will have manual el trim.

The only downside is that heavy cable going all the way back. Oh, and less likely to fail..

Don't worry, you'll get used to it very quickly.

[terrye]

Make sure the vernier knob has had the "quick release" feature removed. This involves removing the rubber boot from the middle of the knob, removing the 1/4" x about 3" rod and installing a chrome plug over the end of the vernier knob. This is recommended in the instruction manual to prevent overcontrolling the trim tab. If this is already done then it is possible to replace the trim tab horn with one with a longer arm. The arm supplied with the kit originally has two holes, one for manual trim (shorter arm) and one for electric trim (longer arm).

Other than that, as others have said, just get used to it.

[N916K]

Isn't there two different lever arms to choose from, one for electric and one for manual? My trim range is a turn or two. I find it's not too sensitive at all.

I have a riveted trailing edge trim tab that doesn't have a twist built into it, that may have something to do with it.

[drycreek]

Isn't there two different lever arms to choose from, one for electric and one for manual?

There aren't two different arms, you just trim the arm accordingly. The electric trim uses a shorter arm and the manual trim uses a longer arm.

[nucleus]

Originally Posted by terrye

Make sure the vernier knob has had the "quick release" feature removed. This involves removing the rubber boot from the middle of the knob, removing the 1/4" x about 3" rod and installing a chrome plug over the end of the vernier knob. This is recommended in the instruction manual to prevent overcontrolling the trim tab. If this is already done then it is possible to replace the trim tab horn with one with a longer arm. The arm supplied with the kit originally has two holes, one for manual trim (shorter arm) and one for electric trim (longer arm).

Other than that, as others have said, just get used to it.

Shorter arm will make it less sensitive, not the longer arm, or am I backwards?

Hans

[Dave_Boxall]

Originally Posted by nucleus

Shorter arm will make it less sensitive, not the longer arm, or am I backwards?
Hans

Sorry but you're backwards. With a long arm a set linear displacement (from the vernier cable) will result in a smaller angular motion of the trim tab than with a short arm.

Dave