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How do you trim for short field?

It would be a good idea before any offset trim (not neutral) is used to go up and do some slow flight and stalls. Flaps and not, turns and straight ahead, right near stall and in the same attitude used during takeoff and landing. My concern would be sudden loss of elevator control, or what some have called "dropping out". It may have little effect or not in Cubs, I never bothered to find out.

In the C-185s I flew when the tail quit in a slow landing when off neutral trim odd things happened depending on stab position. In planes with a trim tab nose down trim can make the elevator more effective at forward CG when landing.

Gary
 
You should always look at Tiger Woods in the morning because he is on the Wheaties box. If you go full power with full nose up trim you are going to have to control the nose up pitch in Cessna or a cub. Both can be a handful and you should practice it at altitude so you are understand what you are in for. The big question is do you really need to go for power for a go around? A cub and Cessna will both Stop descending around 1800 RPM, add enough power to stop the descent. Adjust trim and flaps then proceeded to climb out. You seldom need full power unless you are on a very tight short strip. A place you should Not go if you have not practiced go arounds at longer strips and understanding The forces involved in RPM required to maneuver. Initial pilot training and most biannual reviews will always stress the need for full power. One of the reasons for this is there only so many hours they had to train a pilot. The reason I recommended a new pilot trim for neutral is because they have not had the chance to explore all the realms of flight. As you advance and flying if done properly you can do several things that was advised against in your initial training, banking greater than 60°, using full flaps to takeoff, and several other techniques. The more you fly the more you’ll realize there are very few hard and fast rules, most everything is predicated on the situation or the phrase it depends. I seldom go full power in go rounds I simply add enough power not to hit cumulus granite and adjust from there.

DENNY
 
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Thanks. I will definitely keep your technique in mind for soft field landings.
My cub may be rigged poorly because it does require 3 to 5 turns of trim between no flaps and full flaps. Also it does not want to stall, but just mushes down. I can make it stall by sharply pulling on the stick just before the mush starts. I’m half deaf so have a hard time hearing any difference in wind noise at that low speed, also noise canceling headset probably doesn’t help.


Sent from my iPhone using SuperCub.Org
 
Eddy Lewis said:
….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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Years ago, some friends of mine had bought themselves a Pacer.
None of them had any Pacer time, one guy didn't even have any tailwheel time.
The instructor he ended up engaging to check him out in it was an old air force jet jockey,
mighta done some primary training in a Stearman or something back in the day but he was not what I'd call a tailwheel pilot.
He had my buddy trimming way nose up for landing, then pushing against the pressure on final.
I guess that was supposed to make it easier and/or automatic to flare?
At the time I didn't think too much about the full-power go-around consequences,
my concern was more about what if he got distracted & let the airplane get too slow.
Anyway, my friend did get to where he could fly the pacer pretty well,
whether it was because of his instructor or in spite of him I couldn't say.

FWIW a couple years later the instructor ending up putting a borrowed C170 on it's back,
while doing a "tailwheel checkout" with someone.
No insurance on it or him-- he shrugged, told the out-of-town owner "your plane got wrecked",
and went on his merry way.
He was a likeable guy but I had very little respect for him after that.
I've never been very big on the whole borrowed airplane thing since then.
 
I'm an older really good pilot. Having said that, I trim with the little crank thing on the left side.
 
DENNY said:
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
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Denny are you trimming like this in a PA18?

By a noticeable degree my longest takeoffs and landings are with nose-up trim. I’ve played around a lot with trim settings and any amount of nose up trim would be my last choice.
 
i set the trim for 45-50 at 1000-1100 rpm to fly hands off and never touch it again, just use power and elevator after that.
 
Personally mine is set for Cruise and there it stays until Takeoff when I reset it. Seems to work pretty well for STOL for me. Controls are so light anyhow...

JacobM said:
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.
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spinner2 said:
Denny are you trimming like this in a PA18?

By a noticeable degree my longest takeoffs and landings are with nose-up trim. I’ve played around a lot with trim settings and any amount of nose up trim would be my last choice.
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Hi Dan, I'm having a hard time tracking with up trim increasing your landing distance. The only thing I can think of is (with down trim) the horizontal surfaces are cambered like an inverted airfoil and creating some degree of additional drag, but from touchdown speed and below it would be pretty small. The tradeoff is less up elevator authority, but with proper CG it's probably not an issue.
 
Spinner2
yes it is a PA 18 160 hp. How hard do you break once you get on the ground? That is the reason for the nose up trim. As far as takeoff trim I don’t do full nose up. Depending on load and surface high may use a lot of nose down trim. However, If I am on smooth ground and have a clear runway ahead of me then it is nine turns back from full forward. I do not attempt to pick up the tail. I simply let the tail come up on its own, it will lift a few inches above the ground initially and then at around 35 mph it will start to lift again at that point if I hold the stick and pull flaps it flies off the ground smoothly. By using this technique it takes the pilot out of the equation and adjust for any headwind it will most always be the shortest takeoff. This works empty or with an average load. Some may ask why not lift the tail for a better view? This is a really good idea if you have rough terrain or need to maneuver around obstacles. However when you lift the tail you now squat the front tires this slows you a bit when you first start to roll and gives you more tire drag versus wind drag, It is noticeable if you are down to three psi. The second point is now it is up to the pilot to determine when to rotate, if you rotate too early and hit your tail wheel you are going to lose distance on takeoff. If you rotate too late you won’t strike your tail wheel but you will have given away ground. I’m an old guy so taking my decision out of the rotation and leaving it to the Aircraft to tell me when the wing it’s ready makes it more dependable. Hope that all makes sense to everyone. Every cub is going to vary some from the trim settings I mentioned. And once again for the lower time pilots neutral trim is fine on landing and throw some nose down for takeoff.
DENNY
 
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Speaking of tire pressures Denny.....Do you change your psi between everyday use and STOL comps? More pressure gives less rolling resistance but more bounce if you land firmly and less contact patch while braking. Too little pressure lengthens t/o roll but helps on the backside. Am I over thinking?
 
You’re thinking is spot on. The gear also becomes a factor with tire pressure. I change tire pressure a LOT! And takeoff the difference between 3 pounds and 5 pounds can be 20 to 30 foot. I used to run around 3 1/2 - 4 with bungees now that I have a AOSS I can run a little harder on takeoff because I don’t have the bungee bounce factor on landing. I normally run around 4 1/2 for competition now. I always carry a 1 pound electric compressor with me. If I am going to a new spot or soft spot I will air down to 3 - 3 1/2 pounds for landing once I can inspect the runway if it’s firm enough I will bring it back up to six for takeoff with the pump. For a normal flying known firm spots I run 6 to 8 psi.
DENNY

edit: If you’re not going to be flying for a while pump your bush wheels up to the max pressure listed on the side wall it is a lot easier on the tires and easier to push around.
 
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DENNY said:
Spinner2
yes it is a PA 18 160 hp. How hard do you break once you get on the ground? That is the reason for the nose up trim. As far as takeoff trim I don’t do full nose up. Depending on load and surface high may use a lot of nose down trim. However, If I am on smooth ground and have a clear runway ahead of me then it is nine turns back from full forward. I do not attempt to pick up the tail. I simply let the tail come up on its own, it will lift a few inches above the ground initially and then at around 35 mph it will start to lift again at that point if I hold the stick and pull flaps it flies off the ground smoothly. By using this technique it takes the pilot out of the equation and adjust for any headwind it will most always be the shortest takeoff. This works empty or with an average load. Some may ask why not lift the tail for a better view?

DENNY
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I like these type of discussions.

I brake with the tail up on almost every landing. I hold the tail down with elevator and sometimes power. The brakes are Grove 1.75” double puck, so plenty of braking power. Even when there is plenty of room to roll out I still pick a spot and stop with brakes. It keeps me sharp.

On skis, when I three-point land, I have plenty of nose down trim dialed in. Yesterday I pulled the 31s and put on straight skis since we finally got some valley snow.

D950882D-C03B-4A7E-AF39-4C2F1BFDAD4B.jpeg

You can see where my trim was after sliding up to the hangar.

On takeoff the tail pops up almost immediately trimmed like this and as the airspeed flashes though 25, with 2 notches of flaps pulled, I tug on the stick and up we go. I’m then taking the flaps out followed by trimming for neutral.

If I have full up trim dialed in it just seems to take forever to get airborne.

With up trim dialed in for landing, for me, it is harder to hit the spot and the AOA seems high with reduced visibility.

It is easy to fall into routines and established patterns. So a couple of years ago I re-tried it all, after wondering if my nose down trim was really helping me. Neutral trim, some up trim, full up trim, changes in flaps and flap timing. I’d pace off my distances after landings. Same with takeoffs. I did the same on skis on a big reservoir where I could make dozens of landings and takeoffs in virgin snow and see without a doubt where there were ski tracks and where they ended.

With me in my Cub there was no doubt what worked the best.

When I had my 160 hp PA18 I made similar tests and got started on using some nose-down trim. With this Cub I worked on refining my technique.

This is my experience with thousands of landings FWIW.
 

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I have significantly less experience, but I use nose down trim for my landings and take offs too.
 
KevinJ said:
Speaking of tire pressures Denny.....Do you change your psi between everyday use and STOL comps? More pressure gives less rolling resistance but more bounce if you land firmly and less contact patch while braking. Too little pressure lengthens t/o roll but helps on the backside. Am I over thinking?
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Making fun of my first landing at the last Hondo even I see. ;) I tried a little extra air and it bounced big time. :lol:
 
Steve Pierce said:
Making fun of my first landing at the last Hondo even I see. ;) I tried a little extra air and it bounced big time. :lol:
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I figured your auto inflation/deflation malfunctioned when you were in the pattern. Between your nitrous shot on takeoff and your flap dump switch, you’ve got a lot of buttons to push.
 
Spinner2
I have experimented with trying to blow the tail down as I was braking hard right at the end of the rollout, it worked but lengthen my landing a bit. Something good to have in the back pocket if you felt it going over! bit of thread drift, what cowling do you have? It looks great! Is the engine/ motor lowered?
DENNY
 
Depends on a lot of factors. Are you talking 3 point or in level flight/What type of gear (stock, 3x3, ect)/ Tire size/how much weight on the nose (180HP, club prop or cato, ect). All the factors combine to affect the weight of the tail at a given position. Basic cub with 31 inch tires, 160hp, Borer, stock gear in level flight should be around 80 lbs give or take 10 lbs when the cub is static. Once you add airflow, you add another long list of factors.
DENNY
 
Finally got to get some practice in this weekend, thanks for all of the input everyone.

I had always trimmed a two or three cranks up both for takeoff and landing and when I was trying to land short I was holding a lot of back pressure. So after much experimentation the best I could do is to trim for hands off at the slowest speed that I still had some safety margin. That ended up being almost all the way nose up, I'm sure in part because I'm so heavy, but after trying the full nose down trim that my new friend was telling me about I'm certain that's not the way to go for my particular airplane/situation. I had cones set out and I'm happy with the distances I'm getting for now but I need practice on hitting the spot with this new (to me) approach having the nose so much higher.
 
JacobM said:
Finally got to get some practice in this weekend, thanks for all of the input everyone.

I had always trimmed a two or three cranks up both for takeoff and landing and when I was trying to land short I was holding a lot of back pressure. So after much experimentation the best I could do is to trim for hands off at the slowest speed that I still had some safety margin. That ended up being almost all the way nose up, I'm sure in part because I'm so heavy, but after trying the full nose down trim that my new friend was telling me about I'm certain that's not the way to go for my particular airplane/situation. I had cones set out and I'm happy with the distances I'm getting for now but I need practice on hitting the spot with this new (to me) approach having the nose so much higher.
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Some planes, (O-550 Maule for instance) beg for weight in the tail. As you practice, put some weight in the back (5-10 lbs, more?) and try it. Might change the dynamic for landing.
 
Someone on this forum told me to trim full nose up for landing, and nose down for takeoff.
Advice I try to follow on every flight, for STOL operations.


 
Olibuilt said:
Someone on this forum told me to trim full nose up for landing, and nose down for takeoff.
Advice I try to follow on every flight, for STOL operations.
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Thanks Oli, I enjoy watching your videos, that's a pretty great ride you've got.

I haven't tried that for take off, what is your technique there? Let the tail raise on it's own and full flap/back still when it's ready? I assume the theory is that getting the wing to a low angle of attack quickly reduces wind drag? I'll have to do some more experimenting next time I get out.
 
aktango58 said:
Some planes, (O-550 Maule for instance) beg for weight in the tail. As you practice, put some weight in the back (5-10 lbs, more?) and try it. Might change the dynamic for landing.
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I think for now I'm going to work on getting more consistent and pilot weight reduction. I'll give this a shot when I feel like I've got the technique dialed in.
 
Technique varies with conditions. A steep approach over obstacles on a gusty crosswind day is different than a calm day to a flatlander strip. Power off, power on, obstructions, bumps, traffic, aircraft weight and balance, etc all factor in. I always trim for airspeed but my flap settings, airspeed, and glide slope aren't always the same. Don't get stuck in one setup.
 
Maybe I’m missing something here. 300hrs and 1800 landings? That’s like a landing every 10 seconds? I’m a low time
Cub pilot but I have been told by those with 10s of thousands of cub hours that a shorter strip needs a longer set up. Make it right. Maybe take some more time on your approach if your doing a landing every 10 seconds. (Or tell me
to go back to math class...which is possible too lol)
 
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