Short Field Take Off Techniques

Just curious what techniques are being used for short field take off not to clear an obstacle but just to get in the air. Would like to hear about flap settings, 3 point vs raising the tail, etc, etc.
Brian

Back when I was doing some serious short field flying, we would measure different techniques to see what actually did get us off the ground quickest. All was done on pavement so different surfaces may result in different results. The best we found was to start with brakes locked, no flaps and stick forward. As you accellerated, as soon as the tail came up, pull on as much flaps as you dare while pulling back on the stick. This resulted in the shortest rolling distance. A Supercubs best angle of climb is 45mph with full flaps, so theoretically, you could just keep going up, However that usually depends on the cub. Mine wouldn't , my friends would. We had on 30 " airstreaks, so smaller tires might mean a different setup is better. Weight and balance might effect the technique. I do know that a champ or cheif takes off quicker with everything stuck in you stomach and just let it fly off. So maybe different Supercubs require different techniques. Little things might also make a difference too, like leaving the elevators neutral until you get to 20-30 mph.

S2D, that's basically what I've found to be the best, with the exception of .....I keep the stick neautral, then the instant the tail starts to come up, pull flaps and rotate at the same instant. I've tried other techniques, but that seems to work the best in my plane. Like I said, just curious to what others use. Thanks
Brian

I would assume that technique works only when you're very light. With any weight I need a couple seconds after tail up to pull flaps and rotate.....figuring a standard day/no wind.

I almost never lock the brakes. I throttle up as I am lining up and make turn at full power to take advantage of the momentum. No flaps until I am at flying speed (the stick will feel neutral), then pop one of my three notches of flaps (two if I need it to clear tall trees).

Here's an idea...
You want the shortest take-off, Do this.
Come to Alaska, specifically out in a Tundra area where the wind tends to run a little more freely...wait until a day when the wind is blowing 35-45 kts, untie your plane, turn into the wind--and then you will acheive your shortest take-off technique.
Anyway, regarding technique, Brian is right--consider, if you start with the stick all the way forward then you are adding just that more initial drag with the elevator down. Also, locking the brakes can be dumb if you are taking off from gravel--and it doesn't really help much.
So the technique I know works best when I am Grossed out (which is quite frequently I must say!) --Trim all the way forward, stick neutral (barring no hectic cross-winds...) Brakes holding until about 2200RPM, and then you lift the tail when it is ready to fly, can't really explain it--and then full flaps and rotation, being careful not to over-rotate and stall out. This can be embarrassing indeed--I've seen it happen! Keep it in ground affect as long as possible. Often times I take off from a Ridgetop that isn't even long enuf to get flying at the weight I'm at.....So I just hammer down and when I go over the edge, just push the nose down and fall, feels funny at first but trust! It will gain speed, worst thing you could do is pull back too soon! But you DO have to eventually...
Well folks that should be worth at least ten posts for the length...
Andy

TEST

Knowing that your plane will fly in 150" or whatever feet can be a mixed blessing and this knowledge has crunched a lot of planes. What I'm getting at is if you are on a marginal strip say 250' and you know 150' is all you need, it is best to use every inch to accelerate prior to rotation. I much rather rocket off the strip than stagger around until I have full control.

I think you duster pilots fly, in another dimension, Low, slow, heavy, steep climb outs and dives, tight turns and all requiring the precision of laying down straight lines. What do you use for cable cutters?pak

Short and Shorter.

I was going to stay out of this one untill the ( down deflected elevator creates more drag ) came up again. The only condition that I can think of that this would be true, would be with 8:00 by 4's all the way around. ie; the airplane is sitting (level) to start with, and any elevator deflection would create drag. In reality every airplane, at every weight has a best procedure. Back to the elevator. On the average big wheeled Cub, a deflected elevator is nothing compared to the deflected wing as far as drag goes. If you are majorly over gross, you probably couldn't pick the tail up with a jack. In more normal conditions, the tail comes up quite easily. If you look at my videos shot at Gulkana, you will see that the tail is up ( the wings are level ) and the elevator/ stab. (are also level). At that point the only drag is the brakes. When they are released the major drag is weight. The elevator drag is non-existent. An extreme example on this subject is Denny Martels Cub. On Airstreaks with long gear, he can apply full back stick ( up elevator ) and simply power the tail up to wings level. He then hits the NOX and departs. The runway surface would be the first consideration, then crosswind, then weight. The conclusion that I came to after studying many tapes, is that the average Cub pilot takes a guess as when to rotate. Either the Cub jumps off the ground ( waited too long to rotate ) or it runs another 150 feet. ( rotated too soon ). A good low speed airspeed indicator is a great help. It (see's) what the wing (see's) and can be very accurate. Keep a note pad with you. And keep notes as to weight and speed. (crowd every take-off). If you fly off without flaps you learn nothing. (PRACTICE). You will quickly learn that flaps applied too early will extend your run 100 feet or more. And I have never seen a take-off shortened by slamming the tail into the ground and ( bouncing it off ). Timing is essential between full flaps and rotation. Work it out for your airplane. When you grab the flap handle keep the button depressed untill the flaps are back to normal. It's a smooth interaction between the flap handle and the stick. PRACTICE untill it becomes muscle memory. No, I don't suggest doing this in a strong crosswind. That's another thread. Jerry.

Short again.

I didn't see PAK's reply, untill I had finished mine. In general I agree with you. My exception would be that if the surface is real soft, I can accelerate faster in ground effect. If the surface is hard I can accelerate better on the ground. It's all in knowing your airplane and which proceedure will be best for the condition. If there is nasty wind, no choice. Jerry.

PAK

Propellor works best.

Newbie question:


I have never yanked full flaps on takeoff. I have only done one notch.

Does the risk of stall increase pulling full flaps when the tail comes up? Anything I should be prepared for?

I would attempt in a non-critical situation of course. Just want just want to make sure if I try it it wont rocket me straight up and out of ground effect then quickly back to earth.

How does one ease into this?

Do some slow (very slow also) flight with full flaps - straight and level, turns, climbs, etc. At a safe altitude, obviously. It should display good manners with full flaps at three-point attitude.

Cardiff Kook said:

Newbie question:


I have never yanked full flaps on takeoff. I have only done one notch.

Does the risk of stall increase pulling full flaps when the tail comes up? Anything I should be prepared for?

I would attempt in a non-critical situation of course. Just want just want to make sure if I try it it wont rocket me straight up and out of ground effect then quickly back to earth.

How does one ease into this?

Click to expand...

Before anyone starts doing STOL operations including takeoffs, they should get dedicated Stall/Spin train!! Be very careful pulling an aircraft into the air with flaps. A cub will get into the air before you have good directional control. Lots of cubs have been bent by pilots pulling full flaps and rotating getting the plane airborne only to be blown into stump/log/brush from a crosswind on a tight strip. Read post #9 until you can recite it by memory and think about all the aspects Jerry is talking about. Just for starters set flap so it is easy to reach let the cub run in a tail low attitude and keep the tail low (2 inches off the ground) when you think it will fly don't yank, just add more flap keeping the stick where it is off until it lifts off. It you get it right it will feel like you are lifting the plane off the ground with the flap. Keep flap button depressed and lower to take off setting as speed increases. This will get you used to the stick/flap relationship Jerry is talking about.
DENNY

There is a way to take the pilot out of the equation and let the plane tell you when it is ready to fly whatever the wind is doing. 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 at the initial lift point 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 wing 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. Expect to do a few hundred take offs to figure out the right trim setting. Work the trim forward until you start hitting the tail then back until it clears. Mine covers about a 600 lb range. Lots of other tricks but that is a start.
DENNY

Cardiff Kook said:

Newbie question:


I have never yanked full flaps on takeoff. I have only done one notch.

Does the risk of stall increase pulling full flaps when the tail comes up? Anything I should be prepared for?

I would attempt in a non-critical situation of course. Just want just want to make sure if I try it it wont rocket me straight up and out of ground effect then quickly back to earth.

How does one ease into this?

Click to expand...

Ease in? Don’t yank anything. On a day with no wind or mild wind on the nose, add intermediate flaps from the beginning and do a few takeoffs. Roll a little more nose down trim than normal and pay attention to the attitude and speed. If you’re pulling on the stick to get Vx? Roll the trim back to relieve stick pressure. Remember that trim setting and do a couple more takeoffs. Once you’re set on that? Repeat the exercise with more flaps. Once you know what your attitude, trim, and speed expectations are? Then you might start at one notch and pull more to pop the plane off. It’s a common technique and in calm air it isn’t dangerous. What’s dangerous is trying it in real-world conditions with no practice.

I’ve watched and listened to a lot of free “STOL” seminars. I’d buy a ticket to Jerry’s.

Something to consider:
Density altitude plays a roll as to when it’s appropriate popping full flaps for departure.
Theres a point of diminishing return where full flaps can create more drag than can be overcome by anemic engine.
I did some experimenting and found that, popping full flap beyond 7500’ DA quits being effective. Best technique was set one notch (flaps equal full aileron deflection) prior to rolling, moderate forward stick to get the tail flying (don’t horse the tail up) then light aft pressure to pop it off the ground to get rid of rolling drag, low ground effect till flying speed.
As mentioned, timing and “feel” is everything when rotating, and each plane will behave differently.

Cardiff Kook said:

Newbie question:


I have never yanked full flaps on takeoff. I have only done one notch.

Does the risk of stall increase pulling full flaps when the tail comes up? Anything I should be prepared for?

I would attempt in a non-critical situation of course. Just want just want to make sure if I try it it wont rocket me straight up and out of ground effect then quickly back to earth.

How does one ease into this?

Click to expand...

DENNY said:

There is a way to take the pilot out of the equation and let the plane tell you when it is ready to fly whatever the wind is doing. 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 at the initial lift point 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 wing 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. Expect to do a few hundred take offs to figure out the right trim setting. Work the trim forward until you start hitting the tail then back until it clears. Mine covers about a 600 lb range. Lots of other tricks but that is a start.
DENNY

Click to expand...

What DENNY says. .....Also do not become fixated on a specific number on the airspeed indicator. The instrument is just a secondary crutch,,, your airplane's wing will tell you when it wants to fly. Train your eyes to be looking out the windshield. Learn the attitude of the airplane for whatever maneuver you are attempting. When you learn this, you can then look at the airspeed instrument to see what number the needle is pointed at .... if you really think it is necessary.

I keep the button pushed and feel the flaps and what the airplane is doing. I don't think I ever pull full flaps on takeoff.

Airplane specific to some extent as I would never do this in my 180, but in a super cub I have always taught that the quickest way for the average pilot to get the plane off the ground in little or no crosswind is to start of with full flaps and normal trim (normal flaps, not these newfangled things ) and let the plane fly itself off, then push the nose over right after liftoff to pick up some airspeed. This is especially useful in really rough muddy / snowy conditions where you just need to get off the ground ASAP. Can do similar with 1/2 flaps or no flaps. Not impressive looking in a stol contest, but it works.

Not for strong crosswinds and yes, getting the airspeed up quickly (lowering the nose) after getting off the ground is important to maintaining control.

The above advice about practice and seeing how your plane handles in slow flight is all very good.

sj

He said Newbie Question. I doubt most guys would climb into an unfamiliar airplane and follow some of the procedures detailed here. Most will favor the conservative side until they get a feel for that plane. It's always better for a new guy (or old guy in a new plane) to be able to pull on the stick because he can as opposed to push on the stick because he has to. First flights are usually done with trim rolled forward.

Flaps in a Skywagon are a great takeoff tool. Hopefully when his time comes, Kardiff gets some good Skywagon instruction that includes full power with full flaps. It's impressive providing you're prepared for it.

stewartb said:

It's always better for a new guy (or old guy in a new plane) to be able to pull on the stick because he can as opposed to push on the stick because he has to.

Click to expand...

Exactly - you really need to be on your game to do some of the weird trim stuff folks do for takeoff / landing. Not worth the lack of stabilization in my book for the few extra feet. Get distracted with full nose up on takeoff and now you are in a departure stall.

sj

Semantics is always important the discussing technique. STOL means a lot of different things to different people. To competitors it usually means pushing the ragged edge as hard as you can to win. To others it just means not using up an entire mile long runway. Things done in STOL competition events do cross over to normal runway and off runway flying to some extent but in general several techniques and how close to the edge you should get is very different. For example at STOL events I lock the brakes, lean, run engine up to max RPM (usually 2-3 seconds) final wind check before I release brakes. For normal off runway operations I never lock the brakes just push the power in quick. Now a trick for getting the engine up to speed with that big Borer prop without locking the brakes and picking up rocks on firm dirt/short grass strips. Go out on the runway and do 5 takeoffs without locking the brakes, Just push the throttle full forward and do whatever magic mojo you like. Note your distance. Now do exact same thing but drag your brakes for the first few seconds, how much is a feel thing you will know when it is right. On tar you should see/feel the difference pretty easy also on hard off runway surface. Really soft stuff will already be slowing you down enough that it will most likely not help.
The other thing for off runway flying is I try to keep the plane on the ground until I know I will have good control once I am in the air. Usually 5 MPH or more faster than at STOL competition.
DENNY

SJ said:

Airplane specific to some extent as I would never do this in my 180, but in a super cub I have always taught that the quickest way for the average pilot to get the plane off the ground in little or no crosswind is to start of with full flaps and normal trim (normal flaps, not these newfangled things ) and let the plane fly itself off, then push the nose over right after liftoff to pick up some airspeed. This is especially useful in really rough muddy / snowy conditions where you just need to get off the ground ASAP. Can do similar with 1/2 flaps or no flaps. Not impressive looking in a stol contest, but it works.

Not for strong crosswinds and yes, getting the airspeed up quickly (lowering the nose) after getting off the ground is important to maintaining control.

The above advice about practice and seeing how your plane handles in slow flight is all very good.

sj

Click to expand...

I like to experiment with different techniques from time to time and decided this morning I'd try this method again. This time of year the river level drops and a mile from our airport there are quite a few places to land on the gravel bars. I took off from 3-point attitude from the sod in front of my hangar - about the same distance as my normal technique. A couple minutes later I was on the gravel. On this bar the rocks are fist sized and taking off I left the tail down (Baby Bushwheel) until it flew itself off. Rough. I want to raise the tail but resisted.

Next I went back to normal for me; two notches of flaps combined with full forward trim and lift the tail almost immediately and a few seconds later tug the stick back. If I'm departing the area I let the flaps off and trim.

I played back and forth like this and I much prefer to get the tail up quick for visibility and a smoother ride on rough surfaces.

Nothing changes for me on skis - true soft conditions.

Denny and I had a similar discussion a while ago. :smile: He likes nose up trim. I like nose down. So, the answer I guess is do a lot of experimenting and decide what works the best for you and your plane. Weight and CG will make a difference to some degree, but be willing to try other methods as you gain experience.

edit to add link to previous discussion https://www.supercub.org/forum/showthread.php?56954-How-do-you-trim-for-short-field

spinner2 said:

I played back and forth like this and I much prefer to get the tail up quick for visibility and a smoother ride on rough surfaces.

Weight and CG will make a difference to some degree, but be willing to try other methods as you gain experience.

Click to expand...

Those are the magic words, at least if you're on anything other than a paved or really smooth surface. The bigger the tires, the longer the gear, the shorter the pilot, visibility becomes a really compelling issue. I know, I've flown Pitts S-2s from the back....bat blind, but that's always been on pavement.

I want the tail up just far enough to clear any surface irregularities, which also improves my forward visibility. That's not a "STOL contest" thing, but I'm discussing operations where your takeoff distance can actually cause serious issues.

Get out of a Cub and into a Husky or Scout, or even a heavy Cub on long gear, and that tail won't come up that easy. Nose down trim really helps, by using that trimmable stabilizer. Same goes for Skywagons. Not full nose down trim in those, but.....

What I really care about is not how short I can take off on dry pavement, but what technique is going to get me underway with minimal beating and damage to the plane on rough strips. Granted, some of the techniques definitely cross over, but not all.

MTV

MTV

On rough stuff I usually set the trim the same (I will use lots of nose down if heavy) but do pick up the tail up with the stick pretty high for vis and to protect the tail you can tell when the plane is ready to fly because the rebound from the bumps gets longer and longer. Even though I am sure my way is the best way it is not always the correct way for the situation.:lol:
DENNY

One thing to consider on rocks is rocks either blown or thrown by tires into the tail. Try not to expose the metal or fabric too much unless the ops can eventually pay for the repairs. My experience even on frozen terrain or in icy covered snow.

Edit: That's where nose down trim exposes less than a down elevator.

Gary

Horsepower (thrust), wing area, AOA, flaps, weight…. So many variables. Roll your own. This thread was 20 years silent until Cardiff asked about flaps yesterday. Much has changed in those 20 years.

Depending on the rigging in your Cub, something I’ve done on occasion, just after pulling the flaps on, reach up and pull down on the aileron balance cable to droop ailerons a little. You can’t pull hard, but if the cables are on the loose side you can get a fair amount of aileron deflection. Used to do that on a PA-18A I used to fly. As others have said, know your airplane well before you start playing with advanced techniques that might divert your attention. That moment of distraction could lead to an accident or worse. Always FLY THE AIRPLANE!


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