How do you trim for short field?

[JacobM]

Wondering what everyone uses for a trim setting when they are setting up for a short takeoff and a short landing I'm sure it's been discussed, but I'm having some trouble finding the thread. I've always used a few cranks of nose up for both and I haven't really tried anything else. Is there a generally accepted best practice for how you trim a Super Cub for short field? Or Does it vary so much from plane to plane (due to mods, weight, etc) that you just have to figure out what works best for your craft?

I guess some information on me since I haven't posted here before. Started Flying in 2010 and after watching Loni Habersetzer and Greg Miller too much I bought a Super Cub in 2013. I have about 300hrs and around 1800 landings in my SC so not super experienced but I like to practice. I don't know many other people that fly but met a guy over the weekend and mentioned that my normal touchdown speed for landing short is around 41(gps ground speed, calm wind,Me 270lbs, 30gals of gas) he thought that was absurd, that I should be able to get that into the mid 30's if I were trimmed right. So I figured I'd see what the opinion here is and go do some testing.

 

[sj]

Jacob, you will get lots of answers here, but my belief is that unless you are a Loni or Greg with 100,000 short field landings, trim for stability on approach, just like you would if landing at Denver International.

The difference in ground roll from trim setting will be hard to measure until you can hit your landing spot within a couple feet.

sj

 

[hotrod180]

…..I don't know many other people that fly …..

This to me was the most surprising part of your post, as I don't know many people that don't fly.

 

[JacobM]

This to me was the most surprising part of your post, as I don't know many people that don't fly.

Small somewhat rural town combined with anti-social behavior I guess?

 

[sj]

This to me was the most surprising part of your post, as I don't know many people that don't fly.

Since pilots are literally 1 in 1000 people, if you lived in a town of 800....

sj

 

[JacobM]

Thanks SJ, That's the advice I've gleaned from being a lurker and I do spend a majority of my practice time trying to hit the spot I'm aiming for. I was just surprised that he claimed I could get 5 mph slower if I trimmed full nose down for landing, didn't quite make sense to me. Like I said, haven't really tried it yet but it seems like good way to get a sore arm.

I think we could get to 800 if people are in town for a holiday :smile:

 

[aktango58]

There the Grand Poobah goes using intelligence and reality again


Ignore the man behind the curtain, or the guys you are chatting with that have great advise until you are really good with the plane.

Really good meaning you can tell where that plane will lift off the ground every time with what ever load, and can put it down with the tires either on the line or within a few feet of it, but NOT short- and do that with a stable smooth approach without lots of throttle jamming.

You don't say where you live... maybe some of us are near you and can get together8), many are airplane social, which often makes us out of place in the real world.


All that said, learning your plane is more than landing. It takes lots of time at altitude flying in the buffet, working in and out of stall zones so you can feel what she is doing without the airspeed being a distraction. Learning to turn, use rudders, adjust power by 25 rpm shifts will make it easy to come in steady and smooth for landings. Once you are steady and smooth, and are aware of how your bird talks to you, you can slow it down a touch more, reduce float, and time your descent for touch on the line nice and smooth.

The next step for short landings is to reduce your fuel loads to what you need for the flight... every 60 lbs near the front of the plane is weight lifting the tail and requiring energy to fly and then stop.

Your plane's set up also makes a difference. VG's, square wing, Keller flaps, airspeed slightly off in reading (yes I have seen this also)... so don't get hung up on what other's do, but use it as a guide maybe to see where you can fly it- but learn at altitude.

Direct answer from me though- I am of the stable trim for no pressure camp all the way to landing in all planes. Others like to trim forward and fight the stick to the ground. At some point in working planes the realization came that the 10' difference was not worth the hassle, because I would not be able to fly loaded off anyway.

You are low enough time I suggest you make your life easy, trim neutral and learn to hit the spot with smooth approach and throttle, and you will out fly most of us.

 

[flywhatever]

Before I fly ANY new aircraft, on a calm day, I climb up to 3000' or so and do some air work...stalls, clean, partial and full flap, then some slow flight straight ahead and also light turns up to 30 degrees bank. Get the feel for the plane, watch the airspeed indicator for the slowest speed in clean and full flap configuration. Add 1.5% to these speeds for your approach speed to compensate for margin of error, gusts, etc. No need to be a cowboy yet. You're still learning your machine. Your speeds are obviously going to take into account your weight. The speeds will vary with the weight. Approach longer strips first, then shorter...as your confidence and proficiency grows. I can't tell you what your speed will be, I don't know the weight of your plane, you and gas. No need to anyhow...just do as I stated above and you'll be close to the ballpark. Also, if you're on those big 35" tires, I'd put a little weight in the back and fastened down to compensate for the forward CG of those big tires. Happy flying...

Wondering what everyone uses for a trim setting when they are setting up for a short takeoff and a short landing I'm sure it's been discussed, but I'm having some trouble finding the thread. I've always used a few cranks of nose up for both and I haven't really tried anything else. Is there a generally accepted best practice for how you trim a Super Cub for short field? Or Does it vary so much from plane to plane (due to mods, weight, etc) that you just have to figure out what works best for your craft?

I guess some information on me since I haven't posted here before. Started Flying in 2010 and after watching Loni Habersetzer and Greg Miller too much I bought a Super Cub in 2013. I have about 300hrs and around 1800 landings in my SC so not super experienced but I like to practice. I don't know many other people that fly but met a guy over the weekend and mentioned that my normal touchdown speed for landing short is around 41(gps ground speed, calm wind,Me 270lbs, 30gals of gas) he thought that was absurd, that I should be able to get that into the mid 30's if I were trimmed right. So I figured I'd see what the opinion here is and go do some testing.

 

[pa12drvr]

Jacob, you will get lots of answers here, but my belief is that unless you are a Loni or Greg with 100,000 short field landings, trim for stability on approach, just like you would if landing at Denver International.

The difference in ground roll from trim setting will be hard to measure until you can hit your landing spot within a couple feet.

sj

^^^ This. Set up for a stable approach and do enough landings so that you can identify every reason why you did or didn't hit the spot. When you can nail the spot consistently, or when you can clearly tell yourself why not ("I felt a bit fast/shallow/steep turning to final and therefore floated/had to add power/etc"), so that you can eliminate all other variables, then fiddle with the trim.

For me, I'm not as good a flyer as the -12 is: on some days, I'm perfectly in sync and can hit the spot 9 times out of 10 with minimal energy and speed, no need for throttle play, and without whipsaw on the stick; other days, I miss the spot 5 times out of 10, although usually I can identify some sloppiness or missed judgement on my part ("maybe that wind was 15 knots, not 10") that is connected to the imprecision. When my driving is no longer the critical path to a short landing, I'll work on how much the trim affects landing....ain't anywhere close to that yet. :sad:

 

[JacobM]

Ignore the man behind the curtain, or the guys you are chatting with that have great advise until you are really good with the plane.

You don't say where you live...

The next step for short landings is to reduce your fuel loads to what you need for the flight... every 60 lbs near the front of the plane is weight lifting the tail and requiring energy to fly and then stop.

Not sure I'll ever call myself good, in my experience that leads to complacency.

South Eastern South Dakota

The next step would be to reduce the front seat load about 60lbs, that seems better for the airplane and for me

 

[stewartb]

My take on it- Trim for a speed higher than you expect to touch down. Use the stick to hit the target touch down speed. That way you can relax stick pressure and recover some speed if you need it. Especially with a steep final.

 

[Skywalker]

Yes, trim a bit forward, fly by pulling back with your fingertips. After roundout, when you decide to let the plane down a few inches, (for whatever reason, wheel or 3pt) you aren't pushing thru slop, you just relax a bit without having to activate the other elevator cable.

 

[DENNY]

STOL landings mean a lot of different things to a lot of different people. As a baseline everyone should be talking about a zero wind speed for landing and take off. All air speed calculations and reports should be done off the GPS. This will provide the level baseline. So what is a short landing with you 10 gal of fuel and no wind is it 100 foot landing or a 500 foot landing? Are you talking about breaking hard enough to make the tire skid? Or just for added control? Hitting your spot is very important! The next is how are you going to stop, what kind of surface you have to stop on, how much breaking capability do you have, and how much of that capability can you fully use. Your trim plays an important role on stopping even after you’re on the ground. To fully use brake potential you need to keep your tail high or you will simply skip in skid. The problem with keeping your tail high is now it is very easy to over break and flip onto your nose. Full nose down trim Can hurt you whenyou start getting the tail too high, where as full nose up trim will help you in this situation. hard breaking on soft ground, tundra, and muddy surfaces can be very hazardous.
I personally land with full or near full nose up trim always! I’ve become used to holding forward stick pressure as I prepare to land if you’re not used to doing that it feels very strange at first. The only time I could think of recommending those down trim would be if you had a very strong or gusty tail wind. At this point you only have 300 hours in a cub and that is really not a lot of time, keep working at it but for now trim for a neutral stick.

as far is takeoff goes once again depends on the runway conditions but normally I trim nine turns back from forward in my plane when the tale wants to come up hard it will be ready to fly at pretty much any weight I also use one notch of flaps at takeoff and pick the plane up with the other half when I’m ready to fly. I am on the road trying to do this off my phone so might be a few typos or grammar problems.
DENNY

 

[skywagon8a]

....Me 270lbs, 30gals of gas)

The next step would be to reduce the front seat load about 60lbs, that seems better for the airplane and for me

Jacob, You have given us the clues to answer your question. What is the loaded Center of Gravity when you are flying in relation to the certified allowable range? Operating towards the aft end of that range will improve your short field performance. 270 lbs in the front seat with 180 lbs in the gas tanks with no passenger or baggage places you at or near/forward of the forward limit of the CG envelope. You are a big man, as a result you should at the very least have some baggage ballast tied down in the baggage compartment. If you wish to reduce the weight of this baggage you could place some lead ballast securely at the tail post area.

As far as trim is concerned, I am of the camp which trims to neutral pressure on the stick. Enough so that at most any time I can take my hand off the stick and the plane will not know what I've done. Only your experience will tell you where this position will be during take off. One take off should tell you the answer.

Do us all a favor. Do a loaded weight and balance calculation and post the results here. Then we will know what is what.

 

[dgapilot]

Just to throw this in the mix, the only way I could get descent landings in the Howard was to have full nose up trim and full fuel in the aft fuel tank and about 25 lbs of stuff (survival gear, spare tailwheel, 2 gallons of oil, tiedowns and a 2lb sledge to set them) in the baggage compartment. That airplane handled MUCH better when loaded aft.

As for TriPacers and Pacers, I never really noticed any difference with loading for landings. Always had enough elevator authority. Always trimmed for neutral, or for the climb on a go around to reduce workload. With the one SuperCub I flew a lot, the fuselage was a little out of line. Full nose up trim gave about 60 mph, just right for towing Schweizer gliders. Three turn forward give about 70 for towing glass gliders. I never saw the need to change trim from towing to descending or landing as i wasn’t there for that long. Tow up, split S on release, go into a 60 degree 2G spiral and come down at about 2000’ per min, enter the pattern and land. Rinse and repeat. Banner towing and glider towing it was always loaded forward with just me and gas. Short wings actually make an OK tow plane with the right prop. Not quite as good as a Super Cub, L-19, or Pawnee, but good enough. If you want to learn to land, go tow gliders. There have been days where i’ve done 40-45 tows, that many landings and take offs a day sharpens your skills!


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[Steve Pierce]

I was just surprised that he claimed I could get 5 mph slower if I trimmed full nose down for landing

Make sure your insurance is paid up and get him to show you.

I have tried full nose up landing, full nose down take offs, might have been a tad shorter but I am not real comfortable holding the pressure. I trim the load and between the Thrustline Mod and P-STOL flaps don't touch the trim again. Stabilized approach and hitting my spot is my main goal be it a gravel bar, practising on the grass at the airport or a STOL contest. I was playing last night and was getting in the very low 30s on GPS ground speed but that was with a good wind on the nose. I think some Super Cubs have more angle of incidence in their wings because these things fly at a given speed or sink and I have gotten pretty good and flying it right on that edge. Weight and CG is a big factor as well.

 

[stewartb]

In most cases it’s more about the pilot than the plane. The day I sold my PA-12 to Scooter was the day that plane started landing slower and shorter. I didn’t suck in it. Scooter had 30 years of -12 time and he was just better in it than me. I can see the same in lots of Cub pilots I know. Some guys are just plain better than others. I’m not threatened by that.

Advice to the OP? Go find one of those gifted Cub pilots and sit in back to watch him fly. Spend a few hours observing and you‘ll learn far more than internet discussions can offer.

 

[hotrod180]

…..Get the feel for the plane, watch the airspeed indicator for the slowest speed in clean and full flap configuration. Add 1.5% to these speeds for your approach speed to compensate for margin of error, gusts, etc. ….

1.5% ain't much-- less than 1 mph. :-?

 

[tptailwheel]

I’m from vermillion, where is sd77? Pm me if you want to fly sometime, sj would say I’m more than one in 1000.��

tom

 

[PerryB]

In regard to landing, on a trim-tab airplane (182 for example) nose down trim will slightly increase your elevator authority by kicking up the tab and effectively increasing your up elevator. Of course the price is a very heavy yoke when you flare. On a movable stabilizer like the Cubs or a 185, down trim is just shooting yourself in the foot. You lose authority. My plane requires no trim adjustment. 2450 cruise and short final at full flap are the same. If I really want to drag it in, I'll give it a few cranks up for max elevator authority. As Steve said a few posts above, CG is a huge factor. If you have a forward CG, you'll have to make considerable trim adjustments with changes in speed and power setting. As the CG moves aft, the need for trim diminishes to zero. When a Cub is just right, the only trim adjustments necessary are for changes in loading.
With regard to takeoff, I've heard from some who use down trim, I assume to get the tail up out of the rocks quicker. I've never tried it as I can get mine up almost immediately when solo, and that's the only time I'm doing that kind of flying anyway.

 

[mvivion]

The only instance where I suggest landing an airplane "off trim", meaning that some back or forward pressure is required, is when someone first starts wheel landings.

The key to good wheel landings (and yes, I strongly advocate tail low wheel landings) is to stick the plane on the mains ASAP after the touch. That can be a little tricky at first, as it requires a quick forward motion of the control column, and most folks aren't used to pushing on controls.

So, for those who are having a little trouble sticking the plane right after the touch, I suggest a little bit of nose down trim prior to landing.

At the touch, all they have to do is relax a bit, because they've been holding some back pressure....not a lot, but some. As they relax that back pressure, the stick/yoke comes forward naturally, and it's easy to follow through with more forward pressure to keep it stuck.

It makes a very small difference, but it's often just enough to get over the timing, and make wheel landings work.

As to how much it might change the landing distance, who cares? It's just a technique to learn a technique.

Me, I like to fly airplanes ON trim. Whatever the occasion.

MTV

 

[Eddie Foy]

How do you do this "before you fly any new aircraft?"

Before I fly ANY new aircraft, on a calm day, I climb up to 3000' or so and do some air work...stalls, clean, partial and full flap, then some slow flight straight ahead and also light turns up to 30 degrees bank. Get the feel for the plane, watch the airspeed indicator for the slowest speed in clean and full flap configuration. Add 1.5% to these speeds for your approach speed to compensate for margin of error, gusts, etc. No need to be a cowboy yet. You're still learning your machine. Your speeds are obviously going to take into account your weight. The speeds will vary with the weight. Approach longer strips first, then shorter...as your confidence and proficiency grows. I can't tell you what your speed will be, I don't know the weight of your plane, you and gas. No need to anyhow...just do as I stated above and you'll be close to the ballpark. Also, if you're on those big 35" tires, I'd put a little weight in the back and fastened down to compensate for the forward CG of those big tires. Happy flying...

 

[spinner2]

Yes, trim a bit forward, fly by pulling back with your fingertips. After roundout, when you decide to let the plane down a few inches, (for whatever reason, wheel or 3pt) you aren't pushing thru slop, you just relax a bit without having to activate the other elevator cable.

This is how I setup too. To me it just feels right on final and touchdown to be pulling back a bit on the stick and then release that pressure to let it roll up nicely for a wheel landing. Much like MTV describes too.

I leave the trim right there for takeoff and the tail pops right up and I’m soon taking the trim to neutral.

My testing has proven to me that my takeoffs and landings in my Cub are shortest with this trim.

 

[aktango58]

For takeoff I used to use three turns back from full forward. Was it the shortest? I don't know, but it made for good stick feel in the air.

 

[JacobM]

Make sure your insurance is paid up and get him to show you.

I have tried full nose up landing, full nose down take offs, might have been a tad shorter but I am not real comfortable holding the pressure. I trim the load and between the Thrustline Mod and P-STOL flaps don't touch the trim again. Stabilized approach and hitting my spot is my main goal be it a gravel bar, practising on the grass at the airport or a STOL contest. I was playing last night and was getting in the very low 30s on GPS ground speed but that was with a good wind on the nose. I think some Super Cubs have more angle of incidence in their wings because these things fly at a given speed or sink and I have gotten pretty good and flying it right on that edge. Weight and CG is a big factor as well.

I had the same thought about letting him show me haha but they were only in town a couple days hunting and it sounded like most of his recent time is in one of those Wyoming cubs with the big slats I figured that'd be a lot different than mine.

I can understand weight and CG affecting how you trim and how long it takes to get flying/stopped. What I was having trouble with was how trimming nose down on a landing was supposed to be good for landing slow, couldn't make sense of that in my head.

 

[skywagon8a]

I can understand weight and CG affecting how you trim and how long it takes to get flying/stopped. What I was having trouble with was how trimming nose down on a landing was supposed to be good for landing slow, couldn't make sense of that in my head.

Doesn't make sense to me either, except in airplanes with a fixed stabilizer and a trim tab on the elevator as PerryB mentions above in post #20.

 

[JacobM]

STOL landings mean a lot of different things to a lot of different people. As a baseline everyone should be talking about a zero wind speed for landing and take off. All air speed calculations and reports should be done off the GPS. This will provide the level baseline. So what is a short landing with you 10 gal of fuel and no wind is it 100 foot landing or a 500 foot landing? Are you talking about breaking hard enough to make the tire skid? Or just for added control? Hitting your spot is very important! The next is how are you going to stop, what kind of surface you have to stop on, how much breaking capability do you have, and how much of that capability can you fully use. Your trim plays an important role on stopping even after you’re on the ground. To fully use brake potential you need to keep your tail high or you will simply skip in skid. The problem with keeping your tail high is now it is very easy to over break and flip onto your nose. Full nose down trim Can hurt you whenyou start getting the tail too high, where as full nose up trim will help you in this situation. hard breaking on soft ground, tundra, and muddy surfaces can be very hazardous.
I personally land with full or near full nose up trim always! I’ve become used to holding forward stick pressure as I prepare to land if you’re not used to doing that it feels very strange at first. The only time I could think of recommending those down trim would be if you had a very strong or gusty tail wind. At this point you only have 300 hours in a cub and that is really not a lot of time, keep working at it but for now trim for a neutral stick.

as far is takeoff goes once again depends on the runway conditions but normally I trim nine turns back from forward in my plane when the tale wants to come up hard it will be ready to fly at pretty much any weight I also use one notch of flaps at takeoff and pick the plane up with the other half when I’m ready to fly. I am on the road trying to do this off my phone so might be a few typos or grammar problems.
DENNY

Me with 10 gal of fuel and no wind right now is probably around 250 on grass breaking as much as I'm comfortable with (I don't practice hard breaking all that much mostly because I want my tires and brakes to last). I've never actually measured, I spend most of the time trying to hit the spot and doing slalom's. I'll have to set some cones out and see what I'm actually at because I really don't know a number, I am sure it's more than 100.

Yeah I don't plan to change what I'm doing at this point. It didn't make sense I think the phrase was something like "You know these guys that are landing cubs so short they're trimmed full nose down for landing, that's how they're doing it" just couldn't figure out the aerodynamics of that.

 

[hotrod180]

...With regard to takeoff, I've heard from some who use down trim, I assume to get the tail up out of the rocks quicker. I've never tried it as I can get mine up almost immediately when solo, and that's the only time I'm doing that kind of flying anyway.

I sometimes trim my C180 a bit forward (nose down) of neutral position for takeoff,
that helps the tail come up by itself a bit earlier.
The trim is moving most anytime I change speed or attitude or mode (climb/cruise/descent),
but then again the 180 is very much a trim airplane, not a set-it-and-forget it airplane.

 

[PerryB]

I've got some time in a 185, 188 and 206. They are indeed trim, trim, trim. A nicely balanced Cub spoils you quickly.

 

[Eddy Lewis]

I’m a low time pilot so by no means do I have any suggestions. I do however have a couple questions or maybe clarification from some of the answers. Denny mentioned trimming full nose up and holding stick forward pressure. What happens when you have to make a go around and apply full power. The nose on my cub pitches up abruptly. I can hold it level with lots of stick forward pressure. If I had it trimmed all the way up and applied full power for a go around would I have enough stick forward travel to keep the plane level ? I haven’t tried it and don’t plan to.


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