Do you trim over the numbers?

Totally type dependent. If I don't roll the trim to the stop on my approach I will be holding significant back pressure just to keep proper speed and prevent the nose from dropping.

On a balked landing / go around, my trim is easily overpowered, I have done it many times. Then I can re-trim when convenient.

What you say may be true on the heavy jet you fly, but it's not universally applicable.


while some types may be "easily overpowered" that doesnt mean its a good idea......I used to to show students in Cessna 150s and Bonanzas (gets very dangerous there) what a bad situation a go-around with max trim is. It’s just not a best practice or technique that you’re going to see be applauded or taught by a CFI or any other flight training professional. Sound Airmanship that invokes threat error management is universally applicable.

trim for approach speed and flare with the stick/yoke when its time...running it to its limit is needless.
 
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Good airmanship means you deal with different conditions and different airplanes as best you can. This is a cross section of pilots, missions, and airplane types. A variety of answers is expected. None is right and none is wrong.
 
while some types may be "easily overpowered" that doesnt mean its a good idea......I used to to show students in Cessna 150s and Bonanzas (gets very dangerous there) what a bad situation a go-around with max trim is. It’s just not a best practice or technique that you’re going to see be applauded or taught by a CFI or any other flight training professional. Sound Airmanship that invokes threat error management is universally applicable.

trim for approach speed and flare with the stick/yoke when its time...running it to its limit is needless.

Not true in all cases. My approach speed is about 60mph. To trim for that approach, I need almost full up trim when there isn't a lot of weight in the back. From there I manipulate the yoke as necessary for a good flare.
 
I think this is very type specific. In a Mooney for instance trimming throughout the whole pattern is a must. I am definitely rolling that final up trim over the numbers.

This. Move yoke much away from neutral in any trim setting and the force goes up quickly. I have both a trim button on the yoke (electric) and the big trim wheel between the seats. Gear down? Trim. First notch of flaps? Trim, Rest of flaps? Trim. I even ease in more trim just before flare to help with that and take the force required down to hold the flare.
 
Trim is indeed your friend. Make a power or attitude change, trim the forces out. But on short final, I'm generally done trimming. If I had a little thumb switch, I might feel different . . .

I have a thumb switch but I still don't mess with it. I trim for and hold 75 until it's time to round out.

My wife when flying 182's does trim the thing way nose up on final. It's much easier for her to push forward on final than the pull back in the roundout/flare.
 
You guys that have rules for when to trim and when not to trim apparently don't understand what trimming is for.
 
I trim as soon as I make the turn to final then leave it. Small adjustments on final and the flare aren't that strenuous so I don't trim low to the ground(especially on short final) cause I don't like moving my hand from the throttle down to the trim, then back up. For a T&G in a Cessna I don't touch the trim until all three wheels are off the ground and I'm climbing out. Now if I have electric trim on the yoke, trim till your hearts content.
 
I trim anytime i notice that I'm applying consistent pressure to the yoke in the pattern (and a lot of other places). The plane just behaves better when you're not fighting it!
 
In my old Cherokee 140 I trimmed for desired airspeed on each leg of the pattern. In my RV6 I'm done trimming by the time I'm established on the base leg.
 
it really depends on the airplane and the situation. when I'm flying my 182 sometimes I do sometimes I don't, I don't worry if its over the fence or not, if I feel it needs trim I'll trim it! I often like flying my 182 with a little bit of forward pressure required on my part as it makes the flare a little easier since the nose is quite heavy, and it makes a go around easier as well if needed. When I'm flying the jet at work I absolutely would not trim that low to the ground. Once it's configured for landing with full flaps and gear it generally requires no more trim once you get it stabilized at that point.
 
That's me, too. Full up trim in my 182 with STOL is normal.


Another ditto unless I'm seriously aft loaded, or I'm dragging it in from way too far out to make the airport safely if the engine quits, with gobs of power, I'm out of up elevator trim on final anyway.
 
Another ditto unless I'm seriously aft loaded, or I'm dragging it in from way too far out to make the airport safely if the engine quits, with gobs of power, I'm out of up elevator trim on final anyway.

those of you regarding the full up nose trim, I've never heard of this before. If it requires full nose up trim I'm assuming you all still have plenty of up elevator authority if needed?
 
So I just wondering if this is normal.

So as I'm just crossing the numbers I give a little up trim to help relieve the pressure when I flare. Meaning I just have to give a little back pressure to hold the nose off the ground. If I'm doing a T & G if set the trim back to take off setting.

Am I weird by doing this? Oh I'm flying C172N.



Yes, you're weird. ;)

If I had electric trim, I might do the same.

Mine's manual, so I tend to use as much back trim as I can but I like to maintain a little bit of authority in case of go around, so I usually set it up and don't fiddle with it much. I'll use power to go up and down and try to keep a constant attitude with the ground. The roundout is a non event if done right. Just ease off the throttle and apply a little back pressure. When the mains touch, release the back pressure and cross your fingers. :lol:
 
Rolling that trim to the limit or that far into a landing may feel awesome when you land but its sure fire set up for poor airmanship in the event of a balked landing or go around...trimmed properly you shouldnt need to trim that much.

My exact thoughts when I opened this thread.
 
those of you regarding the full up nose trim, I've never heard of this before. If it requires full nose up trim I'm assuming you all still have plenty of up elevator authority if needed?


Sure. Full up trim doesn't result in full up elevator. The elevator usually "flies" about an inch or two aft of center with a steep flaps 40 approach and trimmed for 65. And it'll be steep. I'll have to go out and try it again soon and let it stabilize and I'll get you an exact speed for my airplane.

My ailerons are also drooped just a bit at flap 40. (They come down with the flaps and then start back up somewhere around 22 degrees of flap if I remember correctly. They about half drooped at 30 and almost all the way back up at 40, but not quite.)

Keep in mind we're both talking about STOL equipped 182s. It'll happily fly along for as long as I have altitude with the elevator trim full aft and power all the way off with tons of airspeed margin.

Mine will even fly a lovely "falling leaf" with the elevator itself held full aft, power off, forever, if you stay on top of any bank that develops with the rudder. Makes the stall fences on top of the wing do a little song of vibrating aluminum, too. No tendency to try to quickly drop a wing, but it'll eventually drop one a little and it will take full rudder to bring it back up. Slowly. But it'll do it all day or until you're out of altitude.

I've demonstrated this for fellow pilots by just starting in level flight and pulling power off smoothly and increasing the elevator until it's at the stop, and then wrapping my arms around the yoke and holding it there in my lap. Gets real quiet, then the nose drops a bit and you hear a little speed, and the nose comes back up, ad infintum.

(The resulting decent rate and porpoising makes a full aft elevator a bad idea for an actual approach to a landing, but frankly if I had to put it into the trees somewhere, I'd be *really* close to full aft, because it'll hit whatever it's going to hit REALLY slow while still under control and with plenty of aileron and rudder authority. YMMV in a non-STOL aircraft.)

As others have pointed out, it's a busy moment if you need to pour the coal in and go around. And you're going to have to puuuuuuush.

The electric trim on the later (even heavier) 182s is generally too slow to wait on, if you need to get the trim out "right now". Plus they simply won't keep flying as slow as mine will.

Have to be ready to get busy with the wheel at any time if you're doing the 40 flap power off thing. Roll that thing like you mean it, and especially if you do it at sea level where the engine has gobs more power...

Up here the nose won't quite come up as much, or the elevator push back quite as hard, with the reduced power from the engine and higher DA.

But it'll still pitch up into a climb that's way too steep if you let it. You can't let it.

Puuuuuuush and start rolling that wheel. :)

If it had any more trim authority, it'd be dangerous to ever roll it all the way up. As it is, it's a handful but manageable if you're paying attention. Which is probably exactly what the trim designers were going for, pre-STOL kit.

It'll fly way behind the power curve with the engine roaring at 55 or even quite a bit slower, too. You won't be needing much up trim for that.

The POH addendum calls for a 39 knot rotation speed for a STOL departure, 44 knot obstacle climb speed while retracting flaps from 30 to 20, and 65 knot climb speed after clearing obstacles.

It's really really slow. I usually wimp out and rotate around 45.

The takeoff data in the POH addendum also has adjustments for weight.

The book claims at 2000 lbs (light), with an IAS of 38 knots at 50' and zero headwind, you'll have a ground roll of 160' at sea level on a cool 59F day. With a 10 knot headwind, 115' ground roll. And if you're lucky enough to have a 20 knot steady headwind, the book claims a 65' ground roll.

At max gross of 2800 lbs, the zero wind takeoff distance goes up to 390' and at 10 knots of headwind, 275', and 20 knots, 175'. But at zero wind it will also take 735' laterally to climb to clear a 50' obstacle. Obviously Vx is a better option than shooting for shortest ground roll.

I haven't pushed it that hard. I usually see a "leisurely" 200'-300' or so for takeoff, and frankly even flying it slower, somewhat puckers my ass. You have zero margin for the engine to even cough, doing that.

The book claims under those same atmospheric conditions with 40 flap and an IAS of 43 at 50' AGL, a 245' landing ground roll. Best I've done is just under 300'. Again, not a big fan of slowing to 43 knots above ground effect. I'll slow to 55 and then to 50 "over the fence".

Why mention all of that? Because it won't trim that slow. At all. After rolling in all the trim available, you will still be pulling on the yoke a little to hold it that slow at Flaps 40.

Fun stuff. Not all that practical in a 182. But fun.
 
I believe the position of the trim tab does in some small way affect elevator effectiveness.

Think about it - with full nose down trim, the trim tab is deflected upwards, as shown here:

image028.jpg


That tab can then ultimately deflect air flowing over the tail upwards with more authority, making the elevator just a tad more effective. The extra pull it takes to flare "fighting" the trim is due to the fact you're deflecting a larger amount of air upwards at the tail.

Similarly, with nose up trim the elevator becomes slightly less effective.

Right?

Note: none of this applies if the trim is via bungees (Piper Apache). Still pondering the effect if the whole tail pivots (Mooney).
 
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while some types may be "easily overpowered" that doesnt mean its a good idea......I used to to show students in Cessna 150s and Bonanzas (gets very dangerous there) what a bad situation a go-around with max trim is. It’s just not a best practice or technique that you’re going to see be applauded or taught by a CFI or any other flight training professional. Sound Airmanship that invokes threat error management is universally applicable.

trim for approach speed and flare with the stick/yoke when its time...running it to its limit is needless.

So how do I handle my particular aircraft, where the limit of trim IS approach speed? Either I have to overpower trim on the occasional go-around, or EVERY time I land...which makes more sense? :idea:

Again...type dependent.
 
Trim whenever you need it to reduce or eliminate back/forward pressure. No such thing as trimming too often in my book. Trim it.
 
Every airplane I've checked out in has had trim set full nose up at best glide in clean, power off configuration, at least on the heavy/forward CG side of the envelope. It will change somewhat dirty with approach power, but it makes sense that there will be a lot of nose up trim.
 
I've never heard of this... Don't see the need in a Skyhawk, and similar aircraft, since there is almost 0 load on the controls at landing speed (less than 55K). That said...I vaguely remember when I took a couple of lessons in a Piper 140 (that's the 2 seater, right?) back in the 70's that I could never seem to get the yoke back far enough to really grease it... Always ended with a "CLUNK" Yoke seemed to come back to a certain point and then you'd almost have to pull up on it to get it all the way back. Noticed the same thing on an Arrow more recently... ( the only 2 pipers I've ever flown)
 
I vaguely remember when I took a couple of lessons in a Piper 140 (that's the 2 seater, right?) back in the 70's that I could never seem to get the yoke back far enough to really grease it... Always ended with a "CLUNK" Yoke seemed to come back to a certain point and then you'd almost have to pull up on it to get it all the way back. Noticed the same thing on an Arrow more recently... ( the only 2 pipers I've ever flown)
In Cherokees (and their derivatives) the control column moves up to signal that you're getting to the last inch or two of aft travel. The pilot doesn't need to push it upward in order to get to full aft; it just naturally tracks that way as you pull back.
 
This is getting too technical for me. Lol
Me too. Trimming has become such a unconscious, natural act for me I couldn't tell you for sure if I do or don't.

If I had to guess, I don't. My last trimming is probably the one I use to stabilize at final approach speed and then the job is to feel the airplane and land when I get to the flare.
 
I've never heard of this... Don't see the need in a Skyhawk, and similar aircraft, since there is almost 0 load on the controls at landing speed (less than 55K). That said...I vaguely remember when I took a couple of lessons in a Piper 140 (that's the 2 seater, right?) back in the 70's that I could never seem to get the yoke back far enough to really grease it... Always ended with a "CLUNK"
If it's a nosegear and had 4 seats, it's a Cherokee. That "CLUNK" is the sound of a greaser in a Hershey Bar Piper :D

I recently started teaching with a small group. On my checkout flights I said I wanted to fly the Cherokee first because I could never land them well. I somehow greased it and started laughing, saying it was the best landing I ever had in one and wanted to quit while I was ahead.
 
Wow Andy, full nose up? If I did that in my Cherokee I'd be doing a loop :).

In a 71 Cherokee 140, I found full up trim, throttle closed, no flaps, no back seat passenger to yield best glide speed. Seemed like a good design feature. Engine out, just crank trim up until it stops.
 
Probably the greatest disservice any of us could do on this subject is to tell someone else how they should do it! So I will say do what works in your airplane but realize the dangers in any particular settings. In my airplane a turbo arrow 4 I am using a fair amount of trim on short final but not full up. Of course a stabilator has a different amount of authority than a standard elevator/horizontal stabilizer has. That said if I go to high throttle as for a go around I know I have to push hard to keep the plane from flying right into a stall unless I immediately take the trim out. (Thank goodness for electric trim). I think that the faster and heavier an airplane is, this becomes more critical. So I am saying do what you need but be cognizant of the dangers.
 
Probably the greatest disservice any of us could do on this subject is to tell someone else how they should do it!

Not really. There are some experts that teach others for a living here. I think they probably have to "tell others how to do it", every time they go up. :)
 
Probably the biggest problem with telling others how do it is that many subjects such as this one are type or situation specific and there is no blanket correct answer.
 
Probably the greatest disservice any of us could do on this subject is to tell someone else how they should do it!
I agree with you, with a modification.

The greatest disservice any instructor can do on almost any hands-on flying subject is to tell a pilot to change a procedure that works.

"Procedure that works" means a technique the pilot uses consistently and doesn't compromise safety. A matter of technique rather than requirement.

I limit it to CFIs in a training environment because of the inherent authority pilots see them having. I hope anyone reading the "how to do it" musings of SGOTI has the judgment to decide if it makes sense for them.
 
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