Trim on final?

FastEddieB said:
Stipulated:

1) A skilled pilot can certainly anticipate the need for trim.

2) It is actually possible to “fly the trim”. Autopilots do it all the time. Perhaps some good pilots do as well.

But it can be a bad habit. I think most instrument instructors can verify the following...

Student sees he or she is 50’ high, and rather than lower the nose directly gives a little nose down trim. Then, distracted, the plane overshoots the desired altitude, and rather than positively raising the nose gives it a little nose up trim, and so on in a repeated cycle. That’s when it’s time to emphasize first achieve your desired pitch attitude, and only then trim out the pressure.

At least that’s how I was taught, and went on to teach.
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Agreed. Pitch, power, trim has worked for well for me and my students.
 
rene86mx said:
My main question is: do you guys trim while on base or final?

Thanks
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luvflyin said:
Gotta luv the simple answers to a simple question. Add me to the list of the yesses, the yups and the yeps. Think of trim as basic an aircraft control as aileron, elevator and rudder. It's there for a reason.
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Yup.
 
rene86mx said:
Hi,

I´m having issues with my landings: too high and too fast are my most common mistakes.

Last weekend on my of my touch and goes I felt the airplane too heavy while ascending.

I think that I trimmed nose down more than needed, corrected and ascended normally.

My main question is: do you guys trim while on base or final?

Thanks
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luvflyin said:
Gotta luv the simple answers to a simple question. Add me to the list of the yesses, the yups and the yeps. Think of trim as basic an aircraft control as aileron, elevator and rudder. It's there for a reason.
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paflyer said:
Yup.
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The OP mentions several things and goes beyond trim woes. In the case of learning to land it can help a great deal to have a viable plan and then learn to execute the plan. Yes, trimming is part of the plan. Other parts of the plan include the overall concept of target airspeeds, flap settings, descent rates, power setting, etc. Perfect practice makes perfect....well at least in the ballpark of perfect.

Some instructors teach this stuff really well, others not so much. After reading the OP it seemed the overall plan was missing or at least not being kept in mind. As always YMWV.
 
FastEddieB said:
Stipulated:

1) A skilled pilot can certainly anticipate the need for trim.

2) It is actually possible to “fly the trim”. Autopilots do it all the time. Perhaps some good pilots do as well.

But it can be a bad habit. I think most instrument instructors can verify the following...

Student sees he or she is 50’ high, and rather than lower the nose directly gives a little nose down trim. Then, distracted, the plane overshoots the desired altitude, and rather than positively raising the nose gives it a little nose up trim, and so on in a repeated cycle. That’s when it’s time to emphasize first achieve your desired pitch attitude, and only then trim out the pressure.

At least that’s how I was taught, and went on to teach.
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I resemble that "student". But just as often, I raise (or lower) the nose directly and it just slows down (or speeds up) and continues it's descent (or climb) when distracted......
 
FastEddieB said:
Stipulated:

1) A skilled pilot can certainly anticipate the need for trim.

2) It is actually possible to “fly the trim”. Autopilots do it all the time. Perhaps some good pilots do as well.

But it can be a bad habit. I think most instrument instructors can verify the following...

Student sees he or she is 50’ high, and rather than lower the nose directly gives a little nose down trim. Then, distracted, the plane overshoots the desired altitude, and rather than positively raising the nose gives it a little nose up trim, and so on in a repeated cycle. That’s when it’s time to emphasize first achieve your desired pitch attitude, and only then trim out the pressure.

At least that’s how I was taught, and went on to teach.
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I think it's important to keep in mind that IAS is a direct function of trim...if you change trim without changing power, you'll change speed. This is how I've seen several pilots consistently exceed aircraft limitations or regulatory limits.
 
FastEddieB said:
2) It is actually possible to “fly the trim”. Autopilots do it all the time. Perhaps some good pilots do as well.
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Years ago and far away I watched a guy fly an F-105 sim by trim. Then I got my two minutes and the stick forces were rather high. I put two and two together and surmised that he flew trim because pushing the stick around would get tiring real quick. Of course he was a rated pilot and I was a scrawny kid so coulda been wrong about the why. The other guy we saw in the sim did move the stick rather than trim so much. Anyway, flying trim seemed to be accepted practice at least in one unit of the air national guard when they were still flying large single engine land aircraft...
 
Most of the time, I just trim whenever there is excess pressure on the controls.
 
Depends on what plane you fly, with mine if I trim and set up for 90knts on downwind for level flight I don't have to touch the trim any more. Throw in 1/3 flaps at abeam the numbers, then another 1/3 on base and I am at 80knts, last 1/3 on final and I am at 70knts.
The force/pressure needed on the Yoke for the flare is next to nothing.
 
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I'll often trim just as I start to enter ground effect. Power doesn't change but there is a change in induced drag. Especially in Cessnas (particularly a 182) a couple swipes at the wheel really help with the round-out. Plus, the slight nose up trim will help in the event of a go-around. For me it's a 'feel' thing, it makes the control forces a little less dramatic in the flare right before touchdown.

In Pipers I don't feel the same need to trim at that point but I am definitely trimming from key position to final as the configuration of the plane is changing.
 
The only airplane I don’t trim on final is the Waco....but that is largely because the trim crank is on the right side of the cockpit. So I make my last trim adjustment on base.
 
Trim,trim,trim,trim is your friend. Trim in all phases of flight.
 
labbadabba said:
I'll often trim just as I start to enter ground effect. Power doesn't change but there is a change in induced drag. Especially in Cessnas (particularly a 182) a couple swipes at the wheel really help with the round-out. Plus, the slight nose up trim will help in the event of a go-around. For me it's a 'feel' thing, it makes the control forces a little less dramatic in the flare right before touchdown.

In Pipers I don't feel the same need to trim at that point but I am definitely trimming from key position to final as the configuration of the plane is changing.
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Yep. My CFI got on to me for not using trim, until I got a 182 lol. I take advantage of it every opportunity I get.
 
Add me to the yes too. Every plane I ever flew that had a trim control I’ve used it on approach
 
Clark1961 said:
Years ago and far away I watched a guy fly an F-105 sim by trim. Then I got my two minutes and the stick forces were rather high. I put two and two together and surmised that he flew trim because pushing the stick around would get tiring real quick. Of course he was a rated pilot and I was a scrawny kid so coulda been wrong about the why. The other guy we saw in the sim did move the stick rather than trim so much. Anyway, flying trim seemed to be accepted practice at least in one unit of the air national guard when they were still flying large single engine land aircraft...
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In a jet like that, the difference between +500vsi and -500vsi is a very small movement of the stick. If you move the stick around and then try to trim out forces you'll likely over correct and start chasing it. So it's easier to bump the stick in the direction you want it to go then give it one or two clicks of trim to see where that puts the VSI. Each airspeed requires a different trim setting so your trim thumb stays busy. I guess I "fly the trim" because when dirty the trim sets my airspeed. If I'm a couple of knots fast, I fix it with clicking the trim and just wait for it to correct. Similar when clean, if I'm climbing or descending when trying to hold level, I bump the stick to stop it and give it two clicks of trim.
 
The more often u trim, the less u will fight the yoke = more brain cells available to figure out what else is going on around u, especially when u are learning how to land. My landings got much better when I started using trim and stopped fighting the yoke

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labbadabba said:
Especially in Cessnas (particularly a 182) a couple swipes at the wheel really help with the round-out. Plus, the slight nose up trim will help in the event of a go-around.
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That’s interesting. I land mine so slow (granted, with the STOL kit) that I’m usually darn near out of up trim at landing or close. I also have 40 flaps so that’s another difference with newer 182s. And I don’t mind a close in approach that’s stabilized and steep with a healthy descent rate.

Obviously I also practice 90 knot finals and burning off energy as the flaps come from 10 to 40 for breaking out at Instrument minimums and that’s fairly “busy” with the trim and usually results in aiming slightly prior to the 1000’ marker and then a “pre-flare” to let the flaps keep eating airspeed before the final flare. Different sort of “stable” and more of a “decelerated” approach needed to slow my STOL airplane up before touchdown after bombing along at 90 headed for the runway.

But for normal slowish approaches, I usually have to push forward pretty hard and trim that up trim away for a Vx or Vy go-around. Otherwise the nose will come up way too fast. I know where the cowl needs to hit slightly above the horizon for Vy and also that works out pretty well as one bar up on the AI if simulating or doing an instrument go-around at full power, so I park the nose there and trim away whatever I get. Usually down trim though.
 
denverpilot said:
That’s interesting. I land mine so slow (granted, with the STOL kit) that I’m usually darn near out of up trim at landing or close. I also have 40 flaps so that’s another difference with newer 182s. And I don’t mind a close in approach that’s stabilized and steep with a healthy descent rate.

Obviously I also practice 90 knot finals and burning off energy as the flaps come from 10 to 40 for breaking out at Instrument minimums and that’s fairly “busy” with the trim and usually results in aiming slightly prior to the 1000’ marker and then a “pre-flare” to let the flaps keep eating airspeed before the final flare. Different sort of “stable” and more of a “decelerated” approach needed to slow my STOL airplane up before touchdown after bombing along at 90 headed for the runway.

But for normal slowish approaches, I usually have to push forward pretty hard and trim that up trim away for a Vx or Vy go-around. Otherwise the nose will come up way too fast. I know where the cowl needs to hit slightly above the horizon for Vy and also that works out pretty well as one bar up on the AI if simulating or doing an instrument go-around at full power, so I park the nose there and trim away whatever I get. Usually down trim though.
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Yeah, I have a lot of down trim on final in a 182 as well. I typically shoot for 65KIAS across the fence with 30 degrees flap. This is in a 2005 T182. Once it get close to ground effect, I'll add a couple swipes of up trim to remove control forces in the flare. Overall my trim is still 'down' in the flare, just a little less down than it was on final. My sight picture in the 182 is pretty flat compared to a 172.

In a 172 it works out to I have a touch of 'up' trim in the flare. Again for me, it's a feel thing. If I'm working against the yoke on roundout I'll trim out the forces. Every plane is a little different. Our club has a 172M and a 172RG. The M model doesn't get much trim at all and flies true, the RG gets a couple healthy swipes.
 
Clark1961 said:
The OP mentions several things and goes beyond trim woes. In the case of learning to land it can help a great deal to have a viable plan and then learn to execute the plan. Yes, trimming is part of the plan. Other parts of the plan include the overall concept of target airspeeds, flap settings, descent rates, power setting, etc. Perfect practice makes perfect....well at least in the ballpark of perfect.

Some instructors teach this stuff really well, others not so much. After reading the OP it seemed the overall plan was missing or at least not being kept in mind. As always YMWV.
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Exactly right. High/fast landings are a result of a lack of planning or a fear of proper approach speeds. A good landing starts way back on downwind.
 
Different airplanes have different trim systems. Some have an aerodynamic trim tab (ala Cessna 172 etc), some have the move the horizontal stabilizer (Pipers), some have a system that moves the elevators (Pawnee), and there are others. All sorts of different trim systems that react differently at different airspeeds etc.

Of course, if you need to get rid of elevator pressure, use the trim all you want. Thats why its there.
 
I guess Im in the minority here. which probably means I need to take a deeper evaluation of what Im doing in the pattern. I pull power abeam the numbers and give it (172) 3 turns of nose up trim. then I hand fly the rest of the way. Ive never felt like I had excessive force that I needed to trim out. I also like trimming just a little nose low so that if I lose track of my airspeed while Im looking outside, I err on the side of too much speed, rather than not enough.
 
Wrench978 said:
I guess Im in the minority here. which probably means I need to take a deeper evaluation of what Im doing in the pattern. I pull power abeam the numbers and give it (172) 3 turns of nose up trim. then I hand fly the rest of the way. Ive never felt like I had excessive force that I needed to trim out. I also like trimming just a little nose low so that if I lose track of my airspeed while Im looking outside, I err on the side of too much speed, rather than not enough.
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If you are keeping the same speed around the turn you may not need to re-trim. I only trim on final for airspeed adjustments.
 
Lachlan said:
No, but I heard he was a towel boy in a bath house. Does that count?
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I thought that was a Turkish Prison. That’s what some old pilot told me when I visited an airliner cockpit as a kid long ago. Think his name was Captain Oveur. :)
 
Wrench978 said:
I guess Im in the minority here. which probably means I need to take a deeper evaluation of what Im doing in the pattern. I pull power abeam the numbers and give it (172) 3 turns of nose up trim. then I hand fly the rest of the way. Ive never felt like I had excessive force that I needed to trim out. I also like trimming just a little nose low so that if I lose track of my airspeed while Im looking outside, I err on the side of too much speed, rather than not enough.
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I was never taught a nose up trim while landing, in case of a sudden go around that could potentially be interesting. I have seen a few people do that though

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Salty said:
Trim for speed, power for descent rate, at least in a lot of planes. If I want to descend faster or slower but I'm on speed, I don't require a trim change.
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Yes, this, in all ‘normal’ planes. In some like my RV10 it’s crystal clear, in others like my Maule it’s not so obvious but it works the same way.

At the earlier stages it seems that everything is changing throughout the approach but as things slow down for you, think about it this way:

Say you’re high but at the speed you want and the yoke is trimmed for the speed, that is, no pressure required. Just pull off some power, slowly. The nose will drop, your descent rate will increase but you’ll find the airspeed will either stay the same (RV10), or return to the same value after some wandering (Maule).

Conversely, you’re low but at the right speed - just add power. The nose will come up, the descent rate will change accordingly and the speed will stay or return to the trimmed value. If you stay off the yoke and the trim during this operation you’ll be surprised how well it works.

Changing airspeed should require a trim change, but it will require a power change as well if your glide path is to remain constant. Trickier here.

A flap change generally requires a trim change, and often you are changing everything else unless you stick to a standard procedure or learn to anticipate what you need.

Enjoy the challenge!


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Wrench978 said:
I guess Im in the minority here. which probably means I need to take a deeper evaluation of what Im doing in the pattern. I pull power abeam the numbers and give it (172) 3 turns of nose up trim. then I hand fly the rest of the way. Ive never felt like I had excessive force that I needed to trim out. I also like trimming just a little nose low so that if I lose track of my airspeed while Im looking outside, I err on the side of too much speed, rather than not enough.
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Could depend on the aircraft. I learned to fly in 81917, a Piper Warrior II and it just didn't need to be retrimmed on base or final. I never understood why, but when I pulled flaps, it would settle on the correct airspeed. But all the 172s have been different and even different Warrior IIs have been different.

What I suspect is that you're flying downwind to base at a slightly lower airspeed than you think and when you turn final, you're where you want to be (which you say is slightly fast). That's ok unless you need a real short field or just want to show off by making the first turn off.
 
Thank you all for your recommendations.

In summary lack of planning.

I reread the chapter on landings in ASA´s the Pilot´s Manual and will create a checklist for pattern flying
 
bflynn said:
Could depend on the aircraft. I learned to fly in 81917, a Piper Warrior II and it just didn't need to be retrimmed on base or final. I never understood why, but when I pulled flaps, it would settle on the correct airspeed. But all the 172s have been different and even different Warrior IIs have been different.
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172 Ms and Ns can be flown so that little our no retrimming is necessary. The ‘kota can certainly be flown so little retrimming is needed. The first trim is after setting power and flaps abeam the touch down point on about a 3/4 mile pattern. Maybe a little power adjustment and trim on final otherwise all yer doing is making turns and setting flaps along with watching position and traffic. Don’t fiddle with stuff just because you can...
 
Not me. I like to throw on some "In this country" by Robin Zander, trim nose down as far as I can and pretend I'm a trucker named Lincoln Hawk trying to win the world arm wrestling championship, a bitchin' new rig and the respect of my deceased wife's father.
 
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