Learning to Trim, and I don't mean fat.

[Bones]

I'm curious. I know of a student that is having a hec of a time maintaining Straight and Level; in my opinion one of he most basic and important building blocks of aviating. From watching him from the back seat on one of his lessons I began to wonder if he understood the triming for level cruise process.

The question I'd like to pose is this:

Can anyone think back to when they were learning to fly and remember any mysteries, confusion, or uncertainties they had about triming an aircraft for straight and level flight?

What made it difficult for you; if you had a tough time with it?

What was the breaking point when it clicked; what helped you set straight and level?

 

[SCCutler]

..dunno, i am still trying!

My main foible is, after leveling off at top of climb, I stopp tweaking it before the plane is done accelerating. Pretty dumb, but I ma getting better about it too

Really want to clean it up, for IMC work.

 

[Michael]

i remember my CFI saying level out then trim. i think i used to try and fly the trim wheel.

 

[SCCutler]

kant tipe, eethur

 

[gibbons]

Trimming for me is a three step process. See below.

 

[Richard]

Trimming for me is a three step process. See below.

You know, Chip, one day that high horse is gonna' rear back and bite you. Maybe last wknd you didn't so much as fly all those planes as sit in them.

As for learning to trim, as in learning any new thing it helps to start with the known and go to the unknown. Perhaps this student understands the need for trim on a speed boat.

 

[poadeleted20]

Trimming for me is a three step process. See below.

I didn't see that box in the Extra.

But to address the problem, as an instructor, the biggest barrier I see to students learning to trim for cruise is that they don't understand the concept of attitude flying in the first place. They can't even put the plane in a true level flight attitude in the first place, and spend their time chasing the altimeter up and down with pitch. Too often, the method they try is to level the plane manually with force, then let go and start playing with the trim wheel to achieve level flight. This usually results in a PIO.

The best means I've found for teaching proper trimming for level flight is first to teach them how to hold altitude properly -- by setting a pitch attitude, holding it (the hard part), seeing how the altimeter reacts, and then adjusting to and holding a new pitch attitude and seeing how that works, refining the process until the plane is holding altitude because they are holding the right pitch attitude. Now they are ready to hold the level flight pitch attitude they achieved and start trimming to zero the stick pitch force.

 

[SkyHog]

This usually results in a PIO.

Small sidetrack - what does PIO stand for? From the context, I'm thinking "Pitch Induced Occilation."

Am I right?

 

[SkyHog]

This usually results in a PIO.

Small sidetrack - what does PIO stand for? From the context, I'm thinking "Pitch Induced Occilation."

Am I right?

 

[spiderweb]

Trimming for me is a three step process. See below.

LOL! I was just thinking that!

 

[spiderweb]

Small sidetrack - what does PIO stand for? From the context, I'm thinking "Pitch Induced Occilation."

Am I right?

LOL--my CFI used to refer to it as PIV--"Pilot-Induced Vomiting"

 

[spiderweb]

The question I'd like to pose is this:

Can anyone think back to when they were learning to fly and remember any mysteries, confusion, or uncertainties they had about triming an aircraft for straight and level flight?

What made it difficult for you; if you had a tough time with it?

What was the breaking point when it clicked; what helped you set straight and level?

Really, this was one of the very few things with which I had no problems. The problem isn't trim, as Ron points out, it is understanding the concept of level. Is the student fixating on something? Instrument training helps, becuase you learn to move the scan around, but with a view outside, it should be that much easier.

I always ask myself, what do I want this plane to do? I'd like to level out here at this altitude I am approaching, and I don't really want a change in airspeed. Fine--I'm already trimimed for that airspeed, so I really only need to reduce power to stop the climb. Do I want to level out and accelerate? Patience is a virtue, in this situation. I won't reduce the power too far, then, but I will hold the altitude with the yoke and wait. Trim once, and it usually won't take much anyway. Now the cruise checklist will call for an adjustment of the throttle, prop, mixture, cowl flaps, and then a reassessment of the engine instruments. By the time that's done, one more tiny adjustment of trim ought to keep things steady.

From what I've seen with many pilots is that they fiddle with the trim mindlessly. Especially when there is electric trim, it seems their thumb is always shoving that thing up and down. Make your power adjustment, put the plane in the right attitude and be patient. Trim once, and maybe a tiny bit more later. I think the trim-fiddling pilots are afraid that if they have to use the elevator at all, there is something wrong.

 

[Bill]

What made it difficult for you; if you had a tough time with it?

My biggest problem was feeling control forces. I could hold the plane level, but when trimming, couldn't properly trim that last bit of control force away. Let go of the yoke, and she'd slowly start drifting from the desired altitude.

 

[Ed Guthrie]

Small sidetrack - what does PIO stand for? From the context, I'm thinking "Pitch Induced Occilation."

Am I right?

Almost. P = Pilot

 

[MSmith]

I
The question I'd like to pose is this:

Can anyone think back to when they were learning to fly and remember any mysteries, confusion, or uncertainties they had about triming an aircraft for straight and level flight?

What made it difficult for you; if you had a tough time with it?

What was the breaking point when it clicked; what helped you set straight and level?

I think I understood the CONCEPT of trimming right away. Actually doing it was a problem.

One day my instructor had me fly straight and level using the trim wheel and rudder pedals with no hands on the yoke to reduce "death grip". I think that day taught me how to trim properly as well.

Other than that, I got better once I had the mental capacity to REMEMBER to trim.

 

[jesse]

I think a lot of times as a student you are so overwhelmed with all the things that are happening and everything you are trying to keep track of you just don't really think of the trim. Which can then in turn cause issues with holding altitude.

It seems that as time passes and you catch up to the plane the issue generally goes away.

 

[poadeleted20]

My biggest problem was feeling control forces. I could hold the plane level, but when trimming, couldn't properly trim that last bit of control force away. Let go of the yoke, and she'd slowly start drifting from the desired altitude.

Right -- that's a problem for a lot of people. What I tell them is to watch the nose versus the horizon (visual or AI). Once you've done your best to trim out the stick force, let the yoke go. If the nose stays where it is, great -- you're properly trimmed. If not, i.e., if the nose rises up or drops, put it back where you want it with the yoke, adjust the trim according to what the nose did when you let go, and try letting go again.

What people do wrong in this case is let go, see the nose move, and then try to move it back with the trim wheel rather than the yoke. That, again, is a way to end up chasing the nose up and down.

 

[Bill]

One day my instructor had me fly straight and level using the trim wheel and rudder pedals with no hands on the yoke to reduce "death grip". I think that day taught me how to trim properly as well.

Nice exercise. One day, towards the end of the PP training, we were in the practice area and my instructor said, "OK, take us home. You may use the rudders, trim wheel, and throttle. Get us as close to landing as you feel comfortable."

So, got vectored for a while, and got to maybe 200agl before I grabbed the yoke.

Good exercise.

 

[Henning]

I'm curious. I know of a student that is having a hec of a time maintaining Straight and Level; in my opinion one of he most basic and important building blocks of aviating. From watching him from the back seat on one of his lessons I began to wonder if he understood the triming for level cruise process.

The question I'd like to pose is this:

Can anyone think back to when they were learning to fly and remember any mysteries, confusion, or uncertainties they had about triming an aircraft for straight and level flight?

What made it difficult for you; if you had a tough time with it?

What was the breaking point when it clicked; what helped you set straight and level?

Trimming in my experience is not taught well until the IR training and not often taught well there. It annoys me how many students I would get with high time but couldn't land consistently. They pretty much always were trying to manhandle the plane rather than using the trim on approach. What broke it for me was long boring flights in planes with no autopilots. Not much to do besides play with "flying with a broken yoke and other fun tricks to master and relieve bordom with".

The trick is in figuring out how much to throw in to get it close, letting the speed stabilize, and then cracking at it againt and waiting til you get there, or if you are already holding pressure to maintain the desired speed and attitude, the just crank the pressure away. If you're changing because of power changes, try rather than changing the power all at once, change the power a bit, catch up the trim...change the power, catch up the trim... so on incrementaly so the aircraft never gets majorly out of trim.

 

[grattonja]

I learned to trim well when CFIs started teaching me to trim to where I thought it needed to be, then let go of the yoke. Sometimes I had it right, sometimes not, and I quickly learned to get it right. I still have to do this sometimes, even as an IR pilot. If I feel like something is off a bit, or I am fighting the plane a bit too much, I let go, and retrim as needed.

Jim G

 

[EdFred]

Nice exercise. One day, towards the end of the PP training, we were in the practice area and my instructor said, "OK, take us home. You may use the rudders, trim wheel, and throttle. Get us as close to landing as you feel comfortable."

So, got vectored for a while, and got to maybe 200agl before I grabbed the yoke.

Good exercise.

Before I was signed off for my IR by my instructor they (the 141 school - even though I was 61) required me to fly an approach using only rudder and throttle to DH on an ILS. The CFII held the yoke in neutral position, and I adjusted as necessary. Got to DH, and took off the foggles, and then hed had me fly it as low as comfortable. Took it down to 50' and then called go-round. Very good exercise.

As far as trimming goes. I just push or pull the yoke as necessary to maintain altitude, then trim until the pressure goes away. From there it's VERY small trim wheel adjustments. Like maybe 1/4-1/2" movements of the wheel (Piper between the seats wheel)

 

[Bill]

I learned to trim well when CFIs started teaching me to trim to where I thought it needed to be, then let go of the yoke. Sometimes I had it right, sometimes not, and I quickly learned to get it right. I still have to do this sometimes, even as an IR pilot.

Jim, this is the only thing that finally broke me from constantly "chasing" altitude with the trim wheel. One day, my II said, "Bill, you're NEVER going to be a good IR pilot until you learn to put your right hand in your pocket."

Trim and let go......trim and let go......

 

[Bill]

I just push or pull the yoke as necessary to maintain altitude, then trim until the pressure goes away.

That is what is hardest for me, I don't have really great feel for when all of the pressure goes away. So I just do my best, then let go of the yoke. You find out right quick how you did...

 

[grattonja]

Jim, this is the only thing that finally broke me from constantly "chasing" altitude with the trim wheel. One day, my II said, "Bill, you're NEVER going to be a good IR pilot until you learn to put your right hand in your pocket."

Trim and let go......trim and let go......

I probably got halfway through my IR training before I really got this concept solidly.

Jim G

 

[spiderweb]

That is what is hardest for me, I don't have really great feel for when all of the pressure goes away. So I just do my best, then let go of the yoke. You find out right quick how you did...

Oooooh. Two suggestions, then:

1) Remove hand pressure slowly. If you go slowly, you will feel any out of trim conditon before the pressure is completely off the yoke.

2) Try to use three fingers on the yoke, at most. You shouldn't ever need more than that unless you are fighting turbulence or big up/downdrafts. In that case, you can tell ATC , and ride the waves a bit, if they allow it.

 

[spiderweb]

Jim, this is the only thing that finally broke me from constantly "chasing" altitude with the trim wheel. One day, my II said, "Bill, you're NEVER going to be a good IR pilot until you learn to put your right hand in your pocket."

Trim and let go......trim and let go......

See post below on the "let go" part.

How do you setup before the FAF, JOOC?

 

[poadeleted20]

One consistent comment here is "I never learned to trim properly until I started instrument training." This goes along with my belief that instructors aren't properly teaching attitude flying from day one in primary training. Because the FAA always talks about "attitude instrument flying," not just "attitude flying," inexperienced instructors (i.e., the majority of instructors giving primary training) don't teach trainees to use those techniques with the big blue/green attitude indicator outside the front window on the first primary training flights. Thus, they lose the chance to make attitude flying a primal instinct at the beginning stages, making it much harder for instrument instructors to get their trainees to make these techniques a habit. But more importantly to this discussion, not teaching attitude flying in primary training means not teaching Student Pilots the best way to use the trim wheel, and that's why we're having this discussion in the first place.

 

[Richard]

One consistent comment here is "I never learned to trim properly until I started instrument training." This goes along with my belief that instructors aren't properly teaching attitude flying from day one in primary training. Because the FAA always talks about "attitude instrument flying," not just "attitude flying," inexperienced instructors (i.e., the majority of instructors giving primary training) don't teach trainees to use those techniques with the big blue/green attitude indicator outside the front window on the first primary training flights. Thus, they lose the chance to make attitude flying a primal instinct at the beginning stages, making it much harder for instrument instructors to get their trainees to make these techniques a habit. But more importantly to this discussion, not teaching attitude flying in primary training means not teaching Student Pilots the best way to use the trim wheel, and that's why we're having this discussion in the first place.

I could not agree with you more! This really is a pet peeve of mine. Basically, it all be summed up as "...inexperienced instructors (i.e., the majority of instructors giving primary training)...". I'm gonna' stop right here before I really lose my cool.

 

[Dave Krall CFII]

Power, pitch, then trim to hold.

Did a few landings once (with one thumb) with a Mooney TLS using only the electric trim ...it was that crisp and fast.

Can be done with Cessna trim wheels too.

 

[spiderweb]

I also think that primary students aren't taught how to find sweet spots for given power settings and altitudes. Instead, I've even seen some instructors just "force" the plane where they want it and then crank the trim in to hold it there. Of course this is allowed, but it doesn't always make sense.

 

[Richard]

I also think that primary students aren't taught how to find sweet spots for given power settings and altitudes. Instead, I've even seen some instructors just "force" the plane where they want it and then crank the trim in to hold it there. Of course this is allowed, but it doesn't always make sense.

Hah! I wasn't introduced to specific power settings until the comm and that only by an Sheriff Aerosquadron CFI who I flew with once or twice. It was during my IR training that I happened to be talking to a USMC pilot who advised me to look for specific RPM/MP settings. I mentioned it to my CFII and he dismissed it by saying it wasn't necessary for what we were doing. Boy, was he wrong!

I guess CFIs teach only the basics for the ratings and it is up to each pilot to take it from there.

 

[spiderweb]

I am starting to see that this is typical. It really sucks. Why not learn the airplane?

Hah! I wasn't introduced to specific power settings until the comm and that only by an Sheriff Aerosquadron CFI who I flew with once or twice. It was during my IR training that I happened to be talking to a USMC pilot who advised me to look for specific RPM/MP settings. I mentioned it to my CFII and he dismissed it by saying it wasn't necessary for what we were doing. Boy, was he wrong!

I guess CFIs teach only the basics for the ratings and it is up to each pilot to take it from there.

 

[Richard]

I am starting to see that this is typical. It really sucks. Why not learn the airplane?

See my new thread, it's gonna' be a party and y'all invited!

 

[judypilot]

I don't recall having much trouble with this, but I also had an instructor who was very good, even though he was inexperienced. I'm not sure experience has everything to do with it. There are conscientious people who know how to teach and fly who don't necessarily have a lot of hours under their belts. I've also had an instructor with lots of experience who was truly awful. I haven't decided whether bad instructors don't know how to fly, don't know how to teach, or both.

I do remember one great lesson, though, which was to fly several patterns (including landings and TOs) in very rough air using only power, rudder, and trim. In my case, it was a lesson in the inherent stability of the aircraft, not so much how to use trim. It broke me of the habit of having a death grip on the control wheel when it's turbulent.

Judy

 

[gibbons]

Trim is something I had problems with as a student and a new pilot even though my instructor taught it from the very beginning. It was a long time ago, but I remember trying to trim the airplane into level flight rather than trying to trim the stick forces away while holding level flight, even though my instructor tried to teach me the correct way.
It's an interesting topic, Eric. Maybe it's something most of us take for granted but something we should spend a good deal more time teaching.

 

[jnmeade]

What works for some people is to form the thumb and index finger into a V and hold them rigidly. Put this V over one horn of the yoke. Push only with the thumb and pull only with the index finger. Trim the pressure out. This prevents the "death grip" and gives a pretty sensitive feel. The last little bit of trim seems to be the hardest to do just right.
Also, some aircraft need frequent trim.
Attitude, power and RPM changes all call for trim changes.

 

[gismo]

One thing it took me quite a while to appreciate is how long an airplane (especially a slippery one) takes to reach a steady speed when levelling off from a climb and the resulting effect on trim. You can "cheat" by overshooting the altitude slightly and using the the short descent back to get up to speed more quickly but if you don't, it can take several minutes to get to a stable condition. If you stop trimming while the plane is still accelerating, you will end up out of trim. If that results in an inadvertent climb you can overshoot the level speed descending back down and end up chasing the pitch, airspeed, and trim for quite a while. This is somewhat less of an issue in a 172 than a Mooney, but it's still there to some extent.

 

[Richard]

One thing it took me quite a while to appreciate is how long an airplane (especially a slippery one) takes to reach a steady speed when levelling off from a climb and the resulting effect on trim. You can "cheat" by overshooting the altitude slightly and using the the short descent back to get up to speed more quickly but if you don't, it can take several minutes to get to a stable condition. If you stop trimming while the plane is still accelerating, you will end up out of trim. If that results in an inadvertent climb you can overshoot the level speed descending back down and end up chasing the pitch, airspeed, and trim for quite a while. This is somewhat less of an issue in a 172 than a Mooney, but it's still there to some extent.

I'm shocked, shocked I tell you. Lance, a person of your caliber would be the last I would consider as succumbing to that OWT. Shooting through your alt to get on step does nothing more than mask poor energy mgmt skills. Do the math, leveling off and leaving power alone until acceleration to desired TAS is easier, faster, more stable than the other technique. A quick poll of pilots yields the result that those who take a long time to accelerate are those who pull the power too soon after leveling off.

 

[gismo]

I'm shocked, shocked I tell you. Lance, a person of your caliber would be the last I would consider as succumbing to that OWT. Shooting through your alt to get on step does nothing more than mask poor energy mgmt skills. Do the math, leveling off and leaving power alone until acceleration to desired TAS is easier, faster, more stable than the other technique. A quick poll of pilots yields the result that those who take a long time to accelerate are those who pull the power too soon after leveling off.

My comment has nothing to do with "getting on the step" which is easily proved to be the OWT it is. And although I wasn't clear about it, I don't normally overclimb to speed up the transition to cruising speed. I only mentioned that this technique is something that some pilots use often or occasionally. I will admit that I'm in the latter category as I will do this if I have a reason to rush the level off.

And you are right that waiting unitl you reach your cruising airspeed before pulling back the power can cut the time down noticeably as well as allow you to reach cruise speed in less time when measured from the point where you first reach the target altitude, but it "feels" like it takes less time overshooting because you would normally consider the overshoot and short descent to be part of the climb because there's no "need" to maintain an exact altitude. That's why I called it "cheating". In my Baron (no turbos here) it still takes at least a few minutes for the speed to stabilize after climbing to my typical cruise altitude of 9-11 thousand MSL if you leave the climb power in (2500 RPM full throttle vs 2300-2450 RPM full throttle).

The real point I was trying to make is that sometimes the problem pilots have attaining proper trim after levelling off from a climb is due to a lack of patience and/or a false expectation that trimming can be accomplished quickly.

 

[Richard]

My comment has nothing to do with "getting on the step" which is easily proved to be the OWT it is. And although I wasn't clear about it, I don't normally overclimb to speed up the transition to cruising speed. I only mentioned that this technique is something that some pilots use often or occasionally. I will admit that I'm in the latter category as I will do this if I have a reason to rush the level off.

And you are right that waiting unitl you reach your cruising airspeed before pulling back the power can cut the time down noticeably as well as allow you to reach cruise speed in less time when measured from the point where you first reach the target altitude, but it "feels" like it takes less time overshooting because you would normally consider the overshoot and short descent to be part of the climb because there's no "need" to maintain an exact altitude. That's why I called it "cheating". In my Baron (no turbos here) it still takes at least a few minutes for the speed to stabilize after climbing to my typical cruise altitude of 9-11 thousand MSL if you leave the climb power in (2500 RPM full throttle vs 2300-2450 RPM full throttle).

The real point I was trying to make is that sometimes the problem pilots have attaining proper trim after levelling off from a climb is due to a lack of patience and/or a false expectation that trimming can be accomplished quickly.

Got it. Thanks for the comeback. I just roll in a little after leveling and then roll in a bit more as she accels. A little bit less and less and less until it's about as perfect as I can get it. Never need a large amount of trim at any given point.