View Full Version : Short Field Take Off Techniques
11-17-2002, 06:47 PM
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.
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.
11-17-2002, 08:49 PM
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
11-18-2002, 07:43 AM
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.
11-18-2002, 07:50 AM
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).
11-22-2002, 01:48 AM
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. :o :D
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... :o
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
11-22-2002, 03:42 PM
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.
11-22-2002, 03:57 PM
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.
Propellor works best.
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