New MT-7 owner with a STEC 50 autopilot and a really ignorant question. I have never flown a plane before with the right rudder trim control like the one in my instrument panel. To be honest, I can't tell a great deal of difference when I push it in or pull it out. What is the appropriate usage for it?

If it’s adjusted correctly, it should work as follows, in straight and level flight:

Half-way out or so, the ball should be centered.

Pushing in will give some left rudder.

Pulling out will give some right rudder.

The effect is subtle enough that if you have your feet on the pedals, you might have a hard time noticing what the trim is doing; it’s not nearly as aggressive as the rudder trim on a Cessna, for example. Try flying along level with your feet off the rudder pedals, and play with the knob to really get a sense of what it does.

A lot of Maule owners just ignore the rudder trim and leave it in one position. I do a lot of long climbs and descents (like straight from takeoff at 5000’ right up to 14,000 ft.) and similar descents, so I use mine a lot. I also like to play with it in level cruise to get the ball perfectly centered, so I can relax my feet on long cross-countries. So I pull it out to climb, push it in to descend, and center it appropriately in cruise.

If yours doesn’t work as described, let us know, and we can walk you through adjusting it properly. If you are getting no effect at all, it’s very possible that it has come disconnected at the right rudder pedal; that’s not uncommon.

Jeremy explained it to me this way for cruise flight.
Use the rudder peddles to center the ball and then adjust the trim to relieve the pressure on your foot.I do this instead of just pulling on the cable, seems to be easier.

wtxdragger wrote: ↑

Thu Mar 25, 2021 9:29 am

Jeremy explained it to me this way for cruise flight.
Use the rudder peddles to center the ball and then adjust the trim to relieve the pressure on your foot.I do this instead of just pulling on the cable, seems to be easier.

I agree with that. It seems like you have a pull it a bit farther if you’re not helping it with your foot.

The way I was describing was mostly to illustrate what it does. Your method is better for actual use, once you understand it.

The spring between the rudder trim control cable and right rudder cable doesn't quite work in a linear way. That's why it's better to center the ball with your feet first and then adjust the rudder trim. If you try to pull the trim control without using your feet, it just stretches the spring some before it has any noticeable effect on the rudder. Then once the initial resistance is overcome, you have to re-adjust the trim control.

As Andy Young noted, the rudder rigging should allow you to fly coordinated without left or right rudder pedal input if the trim control is about halfway out, although the trim control spring doesn't apply equal tension across it's entire range of stretch. There's also a little slack in the rudder cables on most Maules due to stretching over time, so pulling on the trim control removes the slack before it applies much force to the right rudder cable.

Flying uncoordinated will cause one fuel tank to feed more than the other as well as adding drag.

The right rudder trim does not apply any left rudder at all. It is connected only to the right rudder pedal through a spring; so it can only pull the right rudder pedal forward or relax that pull. It cannot move the right rudder pedal toward the rear and is not connected directly to the left rudder pedal.

When a Maule is set up properly it will require some right rudder trim when at straight and level cruise. It would be very annoying if you had to constantly hold hold left rudder on a long leg and have no way to trim left.

During other regimes of flight you are constantly using the both rudder pedals and would not notice the trim at all. You just do what is required to keep the ball centered.

To test you rigging and the effect of the right rudder trim.
1) Set up cruise speed, straight and leverl, with the right rudder trim pushed all they way in, and with the negative flap setting. The ball should be somewhat off to the right, indicating the need for some right rudder.
2) Now once set up and stable, loosen the right rudder control (by turing it about 1/4 turn counter-clockwise), and pull it out till the ball is centered (Maule docs state that should happen at about the first mark on the contol, 1/2" from full in). You may need to help the control a little with a some pressure with your right foot. Once the ball is centered (with the rudder trim pulled out) remove your feet from the rudder pedals, and note if right rudder trim has the authority needed to keep the ball centered with your feed off the pedals. Adjust if necessary.
3) Lock the control by turing the t-handle clockwise.

If at step 1 above you do not need right rudder or, even worse, if you need left rudder (you don't want to have to hold left rudder continuously on a long leg), then your rigging needs adjusted (by someone who understand Maule rigging). The right rudder trim will not help you if you need to hold left rudder, since it can only manipulate the right rudder forward.

If as step 2 above the right rudder trim is not holding the ball centered, you will need to have it checked.

Hope this helps.

It also should be mentioned, there is sometimes quite a bit of drag in the centering of the tailwheel and more so the nose wheel as both will act as rudders.
Therefore, when setting up for straight cruise it is necessary to give a little jog to the rudder pedals to centre the nose or tail wheel, especially after takeoff and climb out as the right pedal will have been depressed to counteract climb out yaw.

I also have a STEC 50 and it is tied rudder for directional control instead of controlling ailerons. So if I am using the auto pilot I don’t the rudder trim.

These answers are great. Thanks.