Trim for takeoff setting

[BillC]

Hi guys,

  I've noticed that it takes a lot of back pressure to rotate my (new to me) M20J for takeoff. I usually fly solo and set the trim to the top of the green band. It still takes too much backpressure to rotate. Today in the hangar, I looked at the elevator while sitting in the copilots seat. With the trim set, I looked at the elevator and noticed it was in the down trim position by about 10-15 degrees. Moving the trim switch to the 'up' position to zero out the trim to where I believe the trim should be set for takeoff, the trim indicator was about 1/2" above the green band. I have flown other Mooneys in the past but don't remember having to apply so much pressure to rotate. It would appear the indicator is inaccurate. The airplane is rigged correctly and flys perfectly. Tomorrow I'll make notes as to what the trim indicates in cruise.  Has anyone else noticed this condition in their 201? What is your elevator position when set to the top of the green band?  What does the trim indicator show when flying solo in cruise?

Thanks, Bill

[Cruiser]

I would rather have more pressure to rotate than trim up too much. Raising the gear will cause the nose to come up and I believe this can contribute to departure stalls if not corrected immediately after takeoff.

With two people in the front I normally trim to the top of the take-off band on the trim indicator. Rotate at 63 KIAS and establish positive rate of climb. After liftoff and gear retraction I trim down to get 100 KIAS for initial climb out of the pattern.

[Skywarrior]

If the amount of trim you've dialed in is not enough, dial in some more. After safely airborne, trim back down a bit, if you wish, before raising the gear.

Err...umm... you do realize that the trim does not move the elevators, right?

[OR75]

how far down and how far up does your trim position indicator goes ?

the trim indicator position can be adjusted (adjustment is under the trim wheel - and a belly panel needs to be open) 

[BillC]

Yes, the trim does go to full up and down according to the indicator. After tomorrows flight I will make notes of the position necessary for proper trim position and adjust the indicator accordingly. The way it is now is just not normal. In the green band, you have to pull too hard to rotate. It would be much safer to be able to set the trim in the green band as specified in the POH instead of ballparking the takeoff trim.  And yes, I'm aware that the trim does not move the elevators. Thanks, Bill

[Shadrach]

Actually Gents, while the trim is not directly connected to the elevators, when viewed from the outside, the elevators do move relative to the horizontal stabs when different trim positions are selected...  I trim so as to require light back pressure for rotation.  The indicators have a take-off flap range selection and it works great.

[pjsny78]

I find that I have the opposite problem. I have to put pressure on the stick to keep the plane from taking off prematurely. I set it to the lower part of the takeoff trim setting.

[1964-M20E]

I find mine is heavy on takeoff as well and I have it trimmed nose high above the takeoff mark.  One day I’m going to go up and see where the trim indicator is when the plane is trimmed for 75MPH IAS and mark it.  Then I’m going to see how that works on the ground for take off or if it is significantly different from where the needle shows it should be for takeoff.

[Hank]

Quote: BillC

Hi guys,

  I've noticed that it takes a lot of back pressure to rotate my (new to me) M20J for takeoff. I usually fly solo and set the trim to the top of the green band. It still takes too much backpressure to rotate. . . I have flown other Mooneys in the past but don't remember having to apply so much pressure to rotate. It would appear the indicator is inaccurate. The airplane is rigged correctly and flys perfectly.

Thanks, Bill

[Piloto]

When the runway is longer than 2000 feet I use no flaps for take off. The rotation is smoother and there is little triming to do when transitioning to climb. The rotation speed is al ittle bit faster and makes you feel like you are in a jet. Try it.

José

 

[John Pleisse]

Trimmed as you are, with only you up front, hands-off it should try to hop a little when you get around 60KIAS. Give it a brisk yank (10lbs maybe) and it will jump into the air. If you have flown a Cherokee of Skyhawk of late, it would be a different sensation.

[Hank]

Quote: Piloto

When the runway is longer than 2000 feet I use no flaps for take off. The rotation is smoother and there is little triming to do when transitioning to climb. The rotation speed is al ittle bit faster and makes you feel like you are in a jet. Try it.

José

 

[xftrplt]

What José said.  Well...almost let a jet.

[BillC]

Well, I flew today doing three takoffs and landings. I found the trim indicator was off by a 1/2" as I thought. With the trim set to the new UP elevator position the airplane rotates perfectly.  I can now lift the nosewheel to takeoff attitude and climb out without the heavy force required previously. At gear retaction, the speed is climbing steadily with no tendency to over rotate. Minimum trim is needed during the flap retaction schedule. It is now a joy to fly and my arm is getting a much needed rest.

To Hank: My POH does not have the notation your POH has. Thanks for your response. 

Thanks for all the input,

 Bill

[sreid]

Quote: BillC

Well, I flew today doing three takoffs and landings. I found the trim indicator was off by a 1/2" as I thought. With the trim set to the new UP elevator position the airplane rotates perfectly.  I can now lift the nosewheel to takeoff attitude and climb out without the heavy force required previously. At gear retaction, the speed is climbing steadily with no tendency to over rotate. Minimum trim is needed during the flap retaction schedule. It is now a joy to fly and my arm is getting a much needed rest.

How did you determine that it was off by 1/2"?  If the only action taken was to do 3 takeoffs, it sounds like maybe you just found where you like it set for your particular taste at a particular weight and balance.  That's fine, set the trim wherever you want its your airplane, but I don't know that you can say that the indicator is mis-rigged based on a few takeoffs.

[OR75]

The trim indicator rigging is part of the rigging of the stabilizer. So if your stabilizer / trim has been rigged or is rigged correctly, then the indicator should be at the mark for take off.

Refer the Service Manual section 27-40 . I looked quickly at that section and the stabilizer should be between -2 degrees 00 minutes and -2 degress 30 minutes when the indicator is in the take off position.

Not trivial to do. You need to level the plane 

 

  

[hoot777]

Remember it is loading dependent. The cg will determine the exact trim required.  We don’t have a chart like large aircraft so we have use the TLAR method. I’d rather be a little nose down than a lot nose up. Only takes a seconds to adjust on rotation.