Trim indicators

[Al Downs]

All three of my indicators for the trim controls seem to need some adjusting to get them in the middle when trimmed for straight and level. How do those little chrome pegs get attached and how can I get them adjusted?

[coppercity]

They simply screw down onto the trim cable. Once you adjust the trim for straight and level flight you should be able to unscrew the trim indicator by gripping the chrome portion and turning counter clockwise a little. Once they are a little loose, slide the indicator to the center position and screw the chrome part back down.

[N89WD]

Just remember, what was once straight and level today may not be on the next flight.

[Roger Lee]

They are just there for a guide. I don't care where the indicator is because you are going to turn the wheel to get whatever effect you want and won't matter where the peg is.

[FastEddieB]

All three of my indicators for the trim controls seem to need some adjusting to get them in the middle when trimmed for straight and level.

 

In my experience, they should indicate in the middle for neutral trim, not for any particular flight condition.

 

IOW, you want the trim tabs aligned with the associated control surface when the indicator is neutral.

 

I'm sure someone will chime in if this is not the case for the CT.

[Roger Lee]

Would it really matter if the indicator was gone?

It wouldn't matter because you really don't care where it is and it is different for each of us and different for each flight

You trim the wheel to remove stick or rudder pressure or trim the plane for flight. So you don't trim to put the indicator in the middle, but trim for force reduction on flight surfaces for each flight. I never look at the wheel. i do it by feel of the control surface.

[FastEddieB]

So you don't trim to put the indicator in the middle, but trim for force reduction on flight surfaces for each flight. I never look at the wheel. i do it by feel of the control surface.

 

True, once in the air.

 

But I think all the planes I've flown have had an indication of where they should be for takeoff and setting that was part of the "Before Takeoff" checklist.

 

If set wrong, I'm pretty sure overpowering it would be possible in most Light Sports. I ended up doing that once in my Sky Arrow where my passenger had accidentally run in full nose-down trim unbeknownst to me.

 

But other planes might require an enormous amount of pressure to overcome an improperly set trim on takeoff, so having an indicator and checking it before takeoff are both important.

[coppercity]

The CT with the light control forces is not a huge impact if the trims are not centered on takeoff, but many airplanes are very heavy on the controls so its important that the pilot know what the trim position is prior to takeoff.

[FastEddieB]

Simultaneous posts - cool.

 

And coppercity managed to say it in far fewer words!

[Roger Lee]

He is right. If the trim wheels are where they were when you landed last they are always close. Our pressure on control surfaces even when out of trim is light. I use the trim to make my plane fly hands off in cruise and I use the pitch trim constantly when taking off, landing or cruising. I rarely ever have to touch the aileron or rudder trim. I never look at the indicators, I just move the wheel until I achieve my goal. We (small LSA aircraft) should only be affecting minor trim on most planes not huge influences like the flaps.

[Al Downs]

Thanks everyone. I agree with all that is said. It seems mine may indicator is way out of wack. Even though we don't really need to look at the indicator, which I don't, I think it is good to realign everything and start from scratch. Is it possible that the cables may have stretched a little making the indicator way off. I had a lot of unwanted pressure last flight and had to adjust on take off climb. Multiple people fly this plane so it is always being adjusted differently.

[Roger Lee]

Like Eric stated. You can loosen the chrome indicator post because it screws into the brass cable slide. Move it where you want it and snug it back down. Don't over tighten it.

[Ed Cesnalis]

He is right. If the trim wheels are where they were when you landed last they are always close.

 

It depends on how you fly. In order to maintain 55kts on approach with the throttle closed I need full nose down trim or to hold pressure. I like to trim but it means I will have too much trim for take off. The stab trim is the only one that I look at the indicator prior to take off.

 

Flaperon trim I set for solo or a passenger and generally get that after takeoff. Rudder trim might be a little left from the last approach but I get that after take off as well.

[FlyingMonkey]

The only indicator peg I care about is for the pitch trim peg, so I can set it approximately neutral for takeoff.

[sandpiper]

 

 

It depends on how you fly. In order to maintain 55kts on approach with the throttle closed I need full nose down trim or to hold pressure. I like to trim but it means I will have too much trim for take off. The stab trim is the only one that I look at the indicator prior to take off.

 

Flaperon trim I set for solo or a passenger and generally get that after takeoff. Rudder trim might be a little left from the last approach but I get that after take off as well.

 

CT-"I need full nose down trim". Clarify.

[Ed Cesnalis]

I have to roll the pitch trim in the nose down direction all the way to the stop. If I don't I will be slow on final at 30 degrees with the throttle closed.

[FlyingMonkey]

I have to roll the pitch trim in the nose down direction all the way to the stop. If I don't I will be slow on final at 30 degrees with the throttle closed.

 

Do you roll the wheel forward or back?

[Ed Cesnalis]

Do you roll the wheel forward or back?

 

If I want to trim the nose down then, top of the wheel forward bottom of the wheel back. Counter clockwise as viewed from left seat.

[Ed Cesnalis]

Whats wrong with pushing the stick forward and keeping it there? If your pitched down so hard on trim, what do you do to flare? Pull back hard on the stick?

 

There is nothing wrong with maintaining speed with forward pressure but it does increase the workload.

 

CTs never require pulling back hard on the stick due to the light forces. If I am trimmed for 55kts when I begin to pull back the effect is the same as releasing forward pressure (when trimmed slower than approach speed).

 

I like to rely on the stab to round out, arrest sink, flare and arrest sink and if I'm trimmed for 55 and I am moving the stick to the aft stop I have more stick to work with.

 

Think about Andy's instructor asking for full nose up trim on approach. The resulting feel is more need for forward pressure and less back stick available, maybe that is why his landings are flat?

 

To say it simply if I am going to use aft stick for energy control I would like to have a lot of aft stick to work with and I like to have the centered stick result in a safe nose down attitude.

 

If your flying an approach why wouldn't you trim for approach speed?

[FlyingMonkey]

There is nothing wrong with maintaining speed with forward pressure but it does increase the workload.

 

CTs never require pulling back hard on the stick due to the light forces. If I am trimmed for 55kts when I begin to pull back the effect is the same as releasing forward pressure (when trimmed slower than approach speed).

 

I like to rely on the stab to round out, arrest sink, flare and arrest sink and if I'm trimmed for 55 and I am moving the stick to the aft stop I have more stick to work with.

 

Think about Andy's instructor asking for full nose up trim on approach. The resulting feel is more need for forward pressure and less back stick available, maybe that is why his landings are flat?

 

To say it simply if I am going to use aft stick for energy control I would like to have a lot of aft stick to work with and I like to have the centered stick result in a safe nose down attitude.

 

If your flying an approach why wouldn't you trim for approach speed?

 

I agree you should be trimmed for approach speed. In fact, if you're not trimming for approach I'd say you are missing one of two primary uses for trim (the other being to neutralize controls for cruise flight).

 

IIRC, you reset your trim neutral point to give you more authority in one direction, correct? My trim is as set at the factory. Abeam the numbers I set the flaps and adjust to the approach speed of 55 knots. As the aircraft is slowing to that speed I roll in full nose up trim. This gives a "not quite" hands-off approach, requiring a little back pressure to maintain 55kt. The airplane will fly about hands off in that condition (with 15° flaps) at about 63 knots, which is best glide per the POH, so I need a little back pressure to keep 55kt.

 

If my landings are a little flat, I would not attribute that to anything other than my failure to get full aft stick, or to let the airplane touch down a few knots before it's really done flying. This is something I continue work to perfect.

[coppercity]

Trimming on approach depends a lot on what type of plane your flying. In the nose heavy airplanes like C182s and 206s I tend to trim full aft on approach to make the forces a little lighter in the flare vs trimming for approach speed, it's a bit more work on the approach but easier during the flare. The downside is during a go around you have to push forward pretty hard. The point is, trim is used to reduce workload on the pilot but its the pilots discretion as to where and when to relieve that workload.

[Tom Baker]

Some CTLS's that I have flown didn't have enough nose down trim to maintain 52-54kt glide speed with full flaps and power off, they would get to slow. I have also not seen some without enough nose up trim for hands off slowflight.

[Ed Cesnalis]

I agree you should be trimmed for approach speed. In fact, if you're not trimming for approach I'd say you are missing one of two primary uses for trim (the other being to neutralize controls for cruise flight).

 

IIRC, you reset your trim neutral point to give you more authority in one direction, correct? My trim is as set at the factory. Abeam the numbers I set the flaps and adjust to the approach speed of 55 knots. As the aircraft is slowing to that speed I roll in full nose up trim. This gives a "not quite" hands-off approach, requiring a little back pressure to maintain 55kt. The airplane will fly about hands off in that condition (with 15° flaps) at about 63 knots, which is best glide per the POH, so I need a little back pressure to keep 55kt.

 

If my landings are a little flat, I would not attribute that to anything other than my failure to get full aft stick, or to let the airplane touch down a few knots before it's really done flying. This is something I continue work to perfect.

 

15° landings are much flatter. You get 55 with full nose up trim at 15° and I get 55 with full nose down trim at 30°.

[FlyingMonkey]

15° landings are much flatter. You get 55 with full nose up trim at 15° and I get 55 with full nose down trim at 30°.

 

Yeah, and that could be the difference. I am about to go back to 30° landings now that my 15s have gotten much more consistent, I'll report my findings.

[N751JM]

I've had the trim indicators loosen up a bit so they would slide freely along the cable. I've gotten in the habit to make sure they are snug when I do the preflight.