How do you use your flaps?

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majourlittle
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How do you use your flaps?

Post by majourlittle »

Apologies if this has been discussed to death, but the search feature *ignores* flaps.

How do you use your flaps on your 140. I have a stock C85 and have heard a number of interesting comments from my local flying group on the use of flaps during landing. Do you go full 40, partial, never use them? what is your thought process on deployment?

Does anyone use these on takeoff?

I know that they are hinged and they become more air-brakes than lift devices, but the do change the wing shape to some degree.

Just looking for some general input before I start experimenting on my own.
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6898
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Re: How do you use your flaps?

Post by 6898 »

Hi good question and a lot of thoughts out there. I never use them on take off as normal flight, but I have tried them ( first notch) and mine seems to climb out more tail high than normal. I do not notice longer or shorter distance with them but I haven't tested that either. As far as landing I use 1 notch on down wind after power reduction and at flap speed than 2nd and 3rd notch turn to base. My CFI requested I always do that to keep in routine when I fly other aircraft with real flaps. Like when I was flying his 180! I'm told our 140's are pretty insufficient when your talking flaps the 180 and the Sport Cub I have flown act way different with flaps
Jeff T 1948 C-140 NC3600V
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a64pilot
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Re: How do you use your flaps?

Post by a64pilot »

My opinion is that the 140 was primarily a trainer and the flaps are there mostly for positive habit transfer when you moved onto larger / heavier aircraft.
However they do work, work as in increase lift and drag. They just aren’t as effective or necessarily as they are on other aircraft

Personally unless the crosswind is excessive,I use all of them on landing, but do not use any for takeoff. They allow lower landing speed and do drop the nose somewhat which allows lower wheel landing speeds and all my landings are wheelies, or almost all anyway.

My 140 with its C-85 and cruise prop just doesn’t have the power to really make them useful in a takeoff, soft field to break ground excepted.
ALL flaps on any aircraft decrease the L/D ratio. or we would leave them down all of the time. so they use excess horsepower to generate lift at lower speeds, and I just don’t have much excess horsepower.

Almost all GA aircraft will climb better with flaps at zero,140 included.

They are a tool, if you have them then learn to use them and become comfortable with them, but it’s likely that the 120 with it not having flaps doesn’t really give up a whole lot to the 140, in my opinion.
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Re: How do you use your flaps?

Post by 6643 »

The flaps can do two things. First, they can make the plane lift off at a slower speed. One technique is to accelerate down the runway with zero flaps and when you hit about 45 mph, pop them on full. The plane will lift off. This is not to say it will climb faster, but it does get you off the ground sooner. This was useful for me when I flew off a sloped runway with trees at the end. I could get off the runway before I got to the point where the runway was lower than the top of the trees.

The second thing they do is lower the nose on descent. This gives you a better view of the touchdown point down in the hole of that sloped runway. I used to come in steeply over the trees with full flaps and a pretty aggressive slip, then wheel it on and get on the brakes.

So, I used the top half of the 1350' runway to take off and the bottom half to land...
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Re: How do you use your flaps?

Post by meloosifah »

I’ve got less than 100 hours in my 140, so take this with a grain of salt. I use 1 or 2 notches on soft fields for takeoff and have tried the full flap pull at 45 mph. It works but I’m not really comfortable with it yet. For landing I use full flaps - it does slow the plane down and gets the nose pointed in the right direction - down. They don’t seem to create a whole lot of lift or drag. In the first 20 hours I forgot the flaps a couple times and it wheeled on perfectly. I don’t think you need them at all but since I have them I use them.
a64pilot
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Re: How do you use your flaps?

Post by a64pilot »

I’ve done quite a lot of takeoff testing on very heavy Crop Dusters, “Popping” the flaps doesn’t do anything, at least not anything measurable.
The theory is leave them up to reduce drag so you accelerate faster, then once you hit a speed they can work, to drop them.
What actually occurs is that at low speed the drag is negligible, so put them down before the takeoff roll, it won’t hurt.

I tried all the tricks, like pushing the nose full down until the tail came up to level the aircraft under the theory that the engine being level gave more thrust, more thrust faster acceleration.

Well in truth from many runs using a very precise measuring system, nothing made much difference, trim the airplane so when she’s ready, she will fly off on her own and you won’t use much if any more distance than if you do all the tricks.
Disappointed me, I really wanted to believe that there were some superior piloting skills that would really pay off.
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Re: How do you use your flaps?

Post by 6930 »

I have used one or two notches of flaps on takeoff a couple of times but didn't find they did much of anything.

On the rare occasion I want to get off the ground "quick", I'll do a three point takeoff with full up elevator...then as soon as the airplane lifts off, pitch forward to arrest the climb and keep the airplane in ground effect until the airspeed builds up and I can safely climb. Word of caution...gotta be quick with the forward pitch as the airplane "leaps" off the ground. I haven't really measured to see if the takeoff roll is any faster with this technique than a tail low 2-point takeoff roll...but I think so.

For landing, I engage full flaps on final once I am sure I have the runway made. Everything else I fly and teach in, I use incremental flaps in the pattern as Jeff mentioned earlier.
Mike Pastore, N2635N
Naper Aero, LL10
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