Trim during pattern

[Tumbleweed]

Trying to improve my trim technique from downwind through to final approach in my CTSW.  Always looking for ways to stabilize my pattern airspeed and get better landings.  Any thoughts or advice on how to trim in the pattern?

Thanks!

 

[Tom Baker]

Not all SW's are the same, some of the later airplanes had a spring in the elevator system. If you have the spring it will require a lot of nose up trim for the glide. If not, trim for around 60 with 15 flaps, and little other trimming around the pattern.

[Tumbleweed]

My CTSW  is a 2007 - the last year before the CTLS - so I would imagine it has the spring.  thanks for the info!

Robin

[Anticept]

Trim is always used to relieve pressure from your stick use, thereby reducing your workload. Focus on figuring out your airspeed and power settings first, trim to relieve pressure. You might even have to come back to the trim a couple times as the aircraft stabilizes, but the point is, trim to relieve, don't trim to drive.

You shouldn't be using trim any other way, or you'll be chasing and increasing your workload (certain super experienced people are the exception).

Even in instrument conditions, once I have a turn established, I am trimming. No matter the airplane or the conditions, I am nearly always trimming after a change in settings, unless super brief, and always after I have my pitch and power established.

[Tom Baker]

9 hours ago, Tumbleweed said:

My CTSW  is a 2007 - the last year before the CTLS - so I would imagine it has the spring.  thanks for the info!

Robin

If you pull the stick aft and it automatically moves to the full forward position you have the spring. This version of the CTSW requires a lot of trim changes. 

[Warmi]

I trim all the way down when turning base and keep it that way until on the ground - I like to feel some pressure when landing - in all other scenarios my usage is just as you described - to relief pressure. 

[FlyingMonkey]

I don't like to think of where trim "should" be set in the pattern or at any other particular time.  The purpose of trim is to relieve control forces.  If there are forces on the stick that require you to apply pressure to counter, then changing trim is indicated.  If not, then not.  There's no need to even look at the trim wheel, you just add or remove trim until the forces on the stick disappear or are not distracting.  But since control forces disappear only at one indicated airspeed, a set trim setting in the pattern commits you to a particular speed as well, which may not always be appropriate to conditions.

Just IMO. 
 

I have used trim when flying at low level to provide a "bias" by adjusting a slight nose-up trim condition.  That way if something distracts you or something goes wrong, the airplane wants to climb away from terrain instead of flying level or descending into the ground.

[Duane Jefts]

“Or at any other particular time”.  I always make sure it’s set properly for takeoff. Small point of order. I agree ~ Trim should be adjusted in flight as required.

[Jim Meade]

I have used trim to anticipate a control force response requirement, especially when establishing cruise attitude in the Citation 500 and 501 which had a manual trim wheel.  So, you can say I was flying the trim wheel or I was anticipating a control force that was going to require a trim adjustment.  In any event, rather than push the nose over and relieve the forces with the trim wheel, I just very slightly adjusted the trim wheel as altitude was approached so as to set the new attitude.

Slightly different topic, how many of you have practiced and demonstrated recovery from a trim tab stall?  Maybe that is the classic case of using trim to respond to control input forces.  What is the classic situation where a trim-tab stall is most likely to occur?

 

[FlyingMonkey]

4 hours ago, Duane Jefts said:

“Or at any other particular time”.  I always make sure it’s set properly for takeoff. Small point of order. I agree ~ Trim should be adjusted in flight as required.

Thank you, Excellent clarification!  Agree 100%

 

[Tom Baker]

4 hours ago, Duane Jefts said:

“Or at any other particular time”.  I always make sure it’s set properly for takeoff. Small point of order. I agree ~ Trim should be adjusted in flight as required.

Properly set can be subjective. Most everything I fly I trim for takeoff. The CT, and specifically the CTLS is one that I do not. I leave the trim set after landing, and hold forward pressure for takeoff and initial climb. The reasoning is that I always takeoff with 15 flaps, and when the flaps go to zero it is in trim. If I trim specifically for takeoff, then I immediately need to re-trim back to where I was before changing the trim. It gets kind of busy when doing touch and goes.

[MEH]

Stirring the pot...

As a CFI, I occasionally ask my students to release the controls on final to demonstrate they are "well trimmed".  This is important for pilots who have difficulty with airspeed variations during the approach-to-land sequence. A well trimmed airplane will be "right-on" the approach airspeed. "Always be well trimmed" is what I teach my students.

However, when I was learning tailwheel, my instructor kept telling me to "leave the trim alone and fly the plane". Then I wondered why, now know why. On my Private Pilot practical examination the DPE put a Post-It note on the Air Speed Indicator for several landings and said "Let's see what you can do."  At the time, I was mortified, but now I know why he did that.  It is about knowing your plane.

Here is my assertion and my challenge: 

There are those who drive the 4 lane of the open highway with only cruise control because if they didn't, they would be driving WAY too fast, or WAY too slow.  I suspect, that most people, however, can drive (with little mental effort) within 5 MPH of the speed limit without continually looking at the speedometer, if they tried. They know what their speed is when they confirm it with the speedometer and then somehow maintain their speed. It is unconscious for them but somehow, they never get a speeding ticket. The truth is that they maintain a constant speed on the open road by subconsciously evaluating their speed based on the way the surroundings pass by them and by the sounds of the air and the road rushing by. With well sealed vehicles, however, this is primarily a visual task, but sound helps.

With aviation, as we are generally away from the ground, the same speed constancy can be attained if we would train ourselves to estimate our airspeed based on auditory, visual, and aircraft handling cues. 

I personally never touch the trim in my CTLS.  It is set for cruise. 

When I was training in antiquated tailwheel aircraft (J3 Cub), my instructor would admonish me to "leave the trim alone and fly the plane". Flying those old planes required a sense of speed based on the sounds and sight picture. At the time, I found the instructor's demand annoying, and counter to what I had been taught.  Always "BE WELL TRIMMED!" was the mandate.

The problem with fiddling with the trim in the CT's is that during the approach and landing phase we typically add 2 or 3 stages of flaps with each flap setting requiring a re-trim. That's a lot of work and a lot of change in the stick pressure close to the ground. From initial deployment of the flaps, where there is a lot of forward stick pressure, to the zero stick pressure, "proper" trim setting.

Flying at the proper approach speed, using sight picture and auditory queues to regulate our airspeed (and not the trim wheel) makes one a more aware pilot.  One must give whatever stick pressure is necessary to yield the desired auditory and sight picture requirements to maintain the required airspeed. That is my assertion (for us experienced pilots.) 

My challenge is to practice the landing sequence enough that with purely auditory and sight-picture cues (and occasionally confirming with the ASI) you can fly the correct airspeed (+/- 5 KIAS) and forget about the trim. This will require you to fly enough that you remember what the sound and sight pictures are which yield the proper airspeed for each flap setting.  Certainly, confirm your airspeed, and then fly the plane with that much stick pressure. Don't fly by staring at the airspeed indicator, but instead, maintain whatever stick pressure it takes to keep that airspeed.  Just like driving the 4 lane highway, which requires a certain foot pedal pressure on the accelerator pedal to maintain that speed, but varying the pressure depending on what your senses (and hills) demand. One can maintain the proper airspeed in the landing sequence with practice, occasionally confirming with the ASI.

FLY THE AIRPLANE and leave the trim alone! Practice enough to know what 60 KIAS with -15 flaps sounds and looks like out the window! You can do it with your car--now do it with your bird.

With this counter cultural assertion,  I erect the lightening rod.

[Anticept]

I'll give you an alternative viewpoint, and several good reasons, why flying an airplane without staying on the trim for most moments is actually a handicap. MEH, I believe even your tailwheel instructor may have had it wrong, but I can't say for sure as I don't know your particular situation. There is a case where I think he would be right, and that's if someone is using the trim as a crutch and end up spending too much time fiddling with it when there are more important things to do.

 

Here are my arguments for keeping your trimming skills up:

1) First and foremost: when you're experienced with the trim, when it's second nature, you give it a little spin and you're good. This lessons your workload, period, even when landing in the pattern. If you make the claim that you are better off not trimming, chances are you just aren't exercising the skill enough. There are occasions when you're probably flying an airplane with unusual characteristics, or the trim is awkward and difficult to use, but that's out of scope here. Trimming is a skill like any other, you have to continue to practice it and it WILL become second nature, and it WILL decrease your workload.

When you get into busy airspace, you need every tool in that toolbox to make it easier. Trust me. You have more important things to worry about than dividing your attention more than necessary, and that includes keeping your hands gripped on that stick the whole time trying to hold it steady.

2) Easier to fly. It really is. Sure, Flight Designs are easy to fly without touching the trim much, but that's an excuse; imagine how much easier it is if you keep it trimmed.

I hated using the trim at first, it was just one more thing to worry about. Even tried to avoid using it for a lot of flying because I didn't want to disturb that perfect cruise trim. It's just excuses, once I finally got in the habit of using it as much as I can... I got very good at it, only taking a second or two to get the trim set reasonably when I changed configurations, airspeed, or altitude. I don't even realize I'm trimming half the time now, it's just a reflex. A Flight Design will let you cheat a bit on it, but I'm going to speak from experience with larger aircraft (but still in the light aircraft category). You will wear yourself out trying to fly a Mooney or a Cirrus if you aren't keeping on the trim. It's harder to fly good approaches without trimming. You'll be chasing that glide more and increasing your workload.

Even when you change flap configurations... once you get it stabilized in the new configuration, all it takes is a quick spin and you take most the pressure off again.

3) You get a better sense of when something has changed with the airplane when you just have to fingertip fly. A pilot who can trim quickly and efficiently will fly the pants off the airplane much more easily than someone who doesn't use the trim much. A trimmed airplane means you don't have to put as much pressure on the stick. That stick is one of the few true "connections" you have to the airplane; you can feel the subtleties a lot easier in your fingertips than just full fisting the stick. It's a lot easier to fingertip fly if it's reasonably trimmed.

4) If you have a weak trim skill, you're not going to get the glide distance. A trimmed airplane is going to hold that airspeed better than you ever will. That's just the reality of it. All you need to be doing in bumpy air is keeping it from oscillating.

The better your trim skill, the better your chances when you lose your engine to get somewhere safe. Engine loss is all about immediately getting that best glide speed, and you have enough other things to worry about than also trying to hold the airplane's speed. So keep that trim skill practiced. Glider pilots and multi engine pilots will especially tell you of its importance to keep that skill on point, in the former case, they need all the glide they can get when they need it, in the latter case, when you do have an engine failure, you're already going to be getting a leg workout on that rudder, you don't need your arm workout too, and this is especially important when trying to do a one engine approach in a non-centerline twin.

 

That said, when you (meaning anyone fitting the bill here) don't have a well developed trim skill, yes, it's going to be annoying, it's going to increase your workload, and you're going to hate it. That's not the fault of the trim, that's the fault of your bad habits. You need to retrain them if you want to be an even better pilot.

Here's my tips for getting good with the trim WITHOUT making it frustrating!

First: Don't try to trim perfectly. That takes too long and you have more important things to do! You'll learn how to do it perfectly and quickly with time, for now, just get it in the ballpark, but STAY FOCUSED ON FLYING THE PLANE.

I am going to repeat that in another way: don't fall into the habit of trying to get it perfect every time.

If you have time to trim it, trim it. If you don't have time to trim, just give that trimwheel a hard spin in the right direction and STOP MESSING WITH IT. Fly the damn airplane first! Just get the trim reasonable and FLY. That may have been what your tailwheel instructor was trying to get you to understand MEH, it's really annoying watching people take too long fiddling with the trim when they have more important things to do. That's turning a tool into a crutch. Just give it good few rolls to get it close enough and LEAVE IT THE FRAK ALONE. You can adjust it again later when you DO have time.

Now, onto a different rule. Get your airplane stabilized FIRST, then trim it. You can even trim as you go to keep pressure low, that's fine. But don't reach for the trim trying to use it to get your airspeed or your level cruise if you haven't stabilized first. You're going to sit there chasing the perfect settings and spending too much time on adjusting trim the whole time. You should be stabilizing with the STICK first. Trim to relieve pressure, not fly the plane.

If you pull back into a climb, give the wheel a spin so you don't have to hold it back as hard. When you level out, give it little rolls from time to time to relieve the pressure. Do you see the pattern? I reiterate, you trim to relieve pressure. Use the stick to hold the altitude, attitude, or airspeed, while you're stabilizing, follow with the trim to ease the pressure off. The goal of a well developed trim skill, is to get to the point that you can fingertip fly. I said earlier, it just plain makes everything EASIER. Learn it. Practice it. Do it.

I'm going to repeat again though because it's the most important thing: YOU DON'T NEED TO BE PERFECT WITH THE TRIM! Just get in the ballpark. It's all about getting close enough. If you can fly the airplane with a couple fingers only instead of a grip, you're close enough!

Yep here it is again. JUST GET IN THE BALLPARK WITH THAT TRIM. Is it in your head yet?

Just to really make sure you get it, JUST SPIN THE WHEEL ENOUGH TO GET CLOSE, YOU'RE NOT PLAYING WHEEL OF FORTUNE HERE, YOU'RE NOT GOING TO WIN A MILLION DOLLARS GETTING IT PERFECT. That level of skill will come eventually. Just get it close.

And of course, lastly, don't bother with the trim if you don't have time for it. Trimming out the airplane in the flare is not the time to play with it for example. If you're doing a quick altitude adjustment, you don't need to trim it there either. I agree that there are times where you don't roll the trim, but that's relatively few. Otherwise, use that friggin trim.

[FlyingMonkey]

I don't think leaving the trim in cruise setting would work well, at least for me.  My airplane cruises 112kt or more most of the time, and I land at 48-52kt.  With trim at a cruise setting during landing there would be a LOT of forward force on the stick.  If your hand were to slip on the stick, you could nose right into the ground.  Likewise on takeoff you need much more force on the stick to leave the runway and you have to hold that force in throughout the climb. 

Others might disagree, but I think setting the trim once to a setting that requires you to fight it whenever not in cruise is a bad idea.  It just makes more work for the pilot and reduces margin of error on takeoff and landing.

I do agree with Corey that the trim is an aid, not a primary control.  I don't usually feel a need to trim often, only if there are fairly gross speed changes.

[CT_MATT]

I will toss out my thoughts since my pitch trim wheel is EXTREMELY stiff and has been since I inherited it 700+ hours ago.  The aileron and rudder trim move extremely easily.  I dont futz with the trim because of this and it goes against what I was taught as well.  The difference in trimmed vs not trimmed pressure for me is minimal and as MEH has mentioned, I just fly the plane...

[Anticept]

If your pitch trim is stiff, the three things you need to check is the tightness on the trim wheel itself, the freeness of movement of the multiplier wheel in the tunnel, then check the stabiliator trim wheel. The first two things aren't a big deal, the last item though is something that you do NOT want to toy with as it's part of the control system and you need to make sure there isn't a problem.

[Jim Meade]

It is instructive to review Airplane Flying Handbook and Instrument Flying Handbook for consistent information on trim.  Much of their information is covered in general in the discussion above.

A couple of comments on context.  Most of us are flying very light airplanes and there is no doubt they can often be overpowered by muscles.  Also, it's probably fair to assume that most of the flying by members of this forum are usually VFR, often severe clear.  It is likely that very little flying is IFR or IMC or even night.  Also, few us devote much time to extreme maneuvers.

In my experience, larger and faster airplanes reward constant attention to trimming, either manually or via autopilot.  CTs can be manhandled.  That does not mean it's a good reason to manhandle them.  Anyone planning to transition into bigger aircraft should make trimming a recurring part of flying, just like using checklists (which many light plane pilots ignore once airborne).

If one's attention is diverted, such as looking at scenery, adjusting an instrument, or dealing with a distracti0n, it is human nature that the muscle control used to offset bad trim is not held constantly and the airplane tends to it's stable airspeed (trim sets airspeed).  Humans can not multitask.  Looking at pretty trees or scary clouds while holding an airplane attitude by muscle.  If a plane is well trimmed, one is not so likely to find it entering an undesired attitude if one's attention to the flight controls is diverted.  

Anyone who expects to fly in IMC learns early in IFR instruction that good aircraft trim is essential to hand flying under the hood or in clouds.

The bottom line is one should trim almost constantly as a regular practice.  Read the referenced Handbooks for all the reasons and for good tips.

 

[Towner]

Since most of the posts are referring to trimming in the pattern, I’m guessing we are focused on pitch trim?
 

While I do use trim, I don’t think I use it near as often as others that are commenting here. I usually use it a little as I slow in the pattern, but I often don’t. I find I use the trim more often for a long climb, decent or to set up cruise. Aileron and rudder trim are really only used in these situations.

We are lucky to have trim available for all three controls. Comments were made earlier about needing to learn how to use trim properly for larger aircraft, with a Mooney mentioned. My Mooney, nor my Cherokee, had trim for all three surfaces. This is just something you had to deal with in most older airplanes. Even when referring to pitch trim only, most of the older, light airplanes were not a problem to fly around the pattern without using trim. I’m sure heavier, higher performance planes may require trim.

I do agree that having a properly trimmed plane is the safest way to go. Getting distracted during climb or approach at low altitudes doesn’t give much room for error. I still think getting to involved with the trim can become a distraction in itself though. 

[Anticept]

Aileron and rudder trim are for cruise. They don't have a significant enough authority, and if you have to go around, now you're fighting against them. The rudder trim works by putting pressure on the sheathe of the cable, so you actually end up reducing the amount of movement in the other direction by a not so insignificant amount when you push it to the extreme.

It's just pitch that's the important one.

[FlyingMonkey]

6 hours ago, Towner said:

While I do use trim, I don’t think I use it near as often as others that are commenting here.

Whenever I notice a pitch control force, I trim it out.  If it's enough for me to notice, it's enough to trim out.  An exception might be if I'm doing something that I know will be very transitory.  For example if I'm trimmed for 80kt and decide to do a power-off stall, I might just set power to idle, let the airplane stall, and then re-trim once I have a new cruise speed.  The deceleration and stall sequence might only be 30 seconds or so, so it's not worth chasing the trim when the airplane trim requirements are going to change constantly until the stall is recovered and airplane speed is stabilized.

As for aileron and rudder trim, I get them set to what is a neutral setting for how I normally fly (solo, around 20g fuel, and about 1100lb gross weight), and I almost never touch them.  If I'm in cruise on a long flight and notice a droopy wing I'll trim it out to avoid fatigue.  I'll also use rudder trim on long trips to balance the fuel in the tanks.  Remember to keep checking the fuel balance if you do that, it is pretty easy to forget the trim is out and you can move too much fuel and and have to do it again the other way (ask me how I know).

 

[Tom Baker]

7 hours ago, FlyingMonkey said:

  An exception might be if I'm doing something that I know will be very transitory.  For example if I'm trimmed for 80kt and decide to do a power-off stall, I might just set power to idle, let the airplane stall, and then re-trim once I have a new cruise speed.  The deceleration and stall sequence might only be 30 seconds or so, so it's not worth chasing the trim when the airplane trim requirements are going to change constantly until the stall is recovered and airplane speed is stabilized.

That is precisely why I don't trim specifically for take off. I trim for when I go to 0° flaps. If I trimmed for take off I would be rolling in nose down trim, and taking right back out when I go to 0° flaps. From lift off to 400 feet where I go to 0° flaps doesn't take very long.

[GrassStripFlyBoy]

On 12/14/2021 at 9:33 PM, Tumbleweed said:

Trying to improve my trim technique from downwind through to final approach in my CTSW.  Always looking for ways to stabilize my pattern airspeed and get better landings.  Any thoughts or advice on how to trim in the pattern?

Hey Tumbleweed!  Appears the topic of trimming has lots of viewpoints, regardless of one's use of trim I think the key aspect to good landings is knowing the right offset from runway on downwind, and when to turn base.  I'm talking non-towered fields.  Towered fields often have us flying in under power and not as consistent based on ATC directions.  The variables in pattern are wind speed, solo or passenger, fuel load, etc.  There is a big difference between solo / light loading / no wind, and gross + high winds.  Trim influences stick loads, but that's about it, the decision making one makes in pattern altitude, offset, and points of turning are far greater influence in establishing a stabilized approach.  I shoot for power off landings, typically cutting power on base or so, I try to always have approaches power off to ensure runway is made, never been a fan of being too low or dragging airplanes in under power.  This means I also do a bit of slip about the 50' high mark to adjust for any excess speed or altitude, being on a short strip sort of drives this.  

So that's my 2 cents, don't fly the same point of turning base, vary this on the factors at play.  Heavy and windy, turn earlier.  Light and calm, extend downwind a bit more.  Learn to slip the CT well, it's easy and provides lots of control over airspeed and decent rate, which I think might be more along what you're seeking for help here.

[Anticept]

One point we definitely agree on: you want to try to position yourself so you will arrive at the airfield safely if you lose power. Not as big of a deal with multi-engine, but that's what I try to do with singles.

If it's a big field around it with plenty of open spots, then I don't care if someone drags it in under power. But if it's an area where it's surrounded by trees, and there's no safe place to touch down if you lose power, absolutely come in a little high.

[FlyingMonkey]

20 hours ago, Anticept said:

One point we definitely agree on: you want to try to position yourself so you will arrive at the airfield safely if you lose power. Not as big of a deal or multi-engine, but that's what I try to do with singles.

Absolutely.  And in a CT that means tight patterns, probably tighter than you'd think it needs to be.  The low inertia of these airplanes means they tend to come down right now.  I like to turn final about 500 feet from the end of the runway.  I'm close enough that when I turn final I usually call "turning short final" on the radio.  You can always add flaps or slip to scrub off excess altitude, but of the engine quits and you are too far out, you are going to be picking tree bark out of your teeth.

[Anticept]

CT's glide ratios are actually a little above the average. You'll get more distance than you think in one.

My commercial examiner couldn't believe the large square pattern I was able to do and still hit my spot on my power off 180.