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do ailerons provide lift?

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Old 01-11-2013, 07:26 AM
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Default RE: do ailerons provide lift?

Hi!
It's very simple! Of course the ailerons are providing lift as they are part of the wing!
Remove the ailerons and the total wing loading will go up!
That's how it is when the airplane flies horizontal with the ailerons in neutral...and that was he was asking about! Not what happens in a turn.
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Old 01-11-2013, 08:45 AM
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Default RE: do ailerons provide lift?

I'm not sure what people mean when they talk about "tightening a turn". To decrease the radius of a turn, you need to bank more. To maintain altitude when you have more bank, you must increase elevator deflection. At some point, you cannot maintain altitude because the elevator cannot position the wing such that the lift vector keeps the plane at a constant altitude. I guess that you would say that the elevator is "turning" the airplane, but you won't maintain altitude, either.

For each radius of turn, there is a bank angle that will be needed. The elevators control the total lift vector of the wing by controlling the angle of attack. If the angle of attack is not enough, the aircraft will descend in a spiral. If the angle of attack is just right, the aircraft will maintain altitude and give a "level" turn. If the angle of attack is higher, the aircraft will climb in the turn.

At any rate, if you have a level turn and you add elevator, you will climb, but not turn faster.

Good elevator performance is desired in high-performance maneuvering because you need to be able to control the angle of attack of the wing without running out of tail "power". For violent maneuvering, you want the controls to remain fully active, and not lose power due to airflow problems. The good elevator performance doesn't make turns tighter, it allows you more control over the pitch axis of the aircraft without loss of effectiveness of the control surfaces.

Now, if you want to move the nose around faster, you can always add rudder, but the aircraft's path won't actually change much. It will careen around in a nice skid, but not have the actual path through the air change at the same rate. Remember, air is a fluid and has a lot of "give" to it. You can slew an aircraft around all three axes and still have quite a delay before the air will "take hold" and cause the path to change.
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Old 01-11-2013, 09:39 AM
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Default RE: do ailerons provide lift?

You are right to say that adding elevator increases the total lift vector. What I don't understand is your claim that doing this does not make the turn tighter. Since the plane is banked in a turn, the lift vector is not vertical. Therefore, increasing that vector increases "lift" in two directions: upward and in the direction you are turning. The extreme case would be if you are banked 90 degrees, in which case adding lift would only tighten the turn and wouldn't raise the nose at all (possible coupling aside). To be sure, we do not usually bank that much except when we're having lots of fun. But the principle is the same even in a 45 degree bank, where about half of the added lift tends to move the plane's nose in the direction in which it is turning.
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Old 01-11-2013, 11:43 AM
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Default RE: do ailerons provide lift?

You guys can post all the charts and facts you want, I know, from personal experience, that if my r/c airplane is in a bank adding back pressure to the elevator does APPEAR to tighten the turn radius. I relate to the science behind it, but for all intents and purposes, at the user level, adding elevator (just back pressure, really) appears to tighten the turn.
As a bit of reinforcement for my observation, I have played around with a mini ultra stick using only the throttle and rudder. You play with nose up trim untill you reach a setting that allows the plane to settle at lower power settings and climb with the throttle higher. (try on a windless day at your own risk). It's excellent practice for power management on final, and requires patience and carefull planning when executing turns onto runway heading, as I find myself reaching for the elevator to help tighten the turn. Other than the few degrees up already set in the trim, though, no extra elevator pressure is required to complete the turn, but it IS noticeablly wider than one using elevator.

So while the experts and facts may disprove, my observations and experience would seem to indicate... at a fixed bank angle, adding back pressure can tighten the turn radius.
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Old 01-11-2013, 12:29 PM
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Default RE: do ailerons provide lift?

OK, if you're in a LEVEL turn, regardless of bank angle, and you increase elevator pressure, you'll start to climb. Yes, "G" forces will increase due to the increased lift vector. I guess you will get a slight increase in turn rate/decrease in turn radius, but it would not be so much. Also, with full-size aircraft, trying to pull to hard will also load the wings to the point that you'll be approaching the stall. Because it's not at a 1G loading, you'll get what's known as an accelerated stall.

With models, when the flyer adds elevator to "tighten" the turn, they're actually stopping the descent and the model looks like the turn is tightening. It really isn't. What the RC modeler perceives is usually quite different from what's actually happened. That's why we get such myths as "the model climbs better into the wind", "a crosswind got under the wing and made it crash", "turning downwind is dangerous and the model will tend to drop", and on and on.
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Old 01-11-2013, 01:16 PM
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Default RE: do ailerons provide lift?

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I guess you will get a slight increase in turn rate/decrease in turn radius, but it would not be so much.
Why "slight"? In a 45 degree bank, you'd get about the same contribution to tightening the turn as you would to raising the nose, wouldn't you? In an 80 degree bank, you'd get more contribution to the turn than to up. And while you would certainly get additional lift, additional lift is what you want if you are turning more tightly, isn't it?

I've spent a fair amount of time on these forums trying to fight the downwind-turn myth, the "airspeed increases when you turn into the wind" myth, and so on. None of these things has anything to do with what we're talking about here.
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Old 01-11-2013, 01:43 PM
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Default RE: do ailerons provide lift?


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ORIGINAL: Top_Gunn

You are right to say that adding elevator increases the total lift vector. What I don't understand is your claim that doing this does not make the turn tighter. Since the plane is banked in a turn, the lift vector is not vertical. Therefore, increasing that vector increases "lift" in two directions: upward and in the direction you are turning. The extreme case would be if you are banked 90 degrees, in which case adding lift would only tighten the turn and wouldn't raise the nose at all (possible coupling aside). To be sure, we do not usually bank that much except when we're having lots of fun. But the principle is the same even in a 45 degree bank, where about half of the added lift tends to move the plane's nose in the direction in which it is turning.
The lift vector is always opposing gravity. Gravity vector is always pointing to earth center.

"Adding elevator" means what exactly? That you added elevators to the stab? If it means moving the elevator, you have two options, "up or down". Either one "adds"

Giving a plane"up" elevator changes, increasesthe wing AOA when the plane is flying S&L or is in general upright flight mode.Increased wing AOA creates the added lift. And for many planes you can give too much "UP" elevator to the point the wing AOA is too high, then the wing stalls and dumps lift quickly

If the plane is inverted and you give it "UP" elevator, wing AOA decreases and dumps lift

Ailerons are part of the wing area. They create lift, roll and drag forces
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Old 01-11-2013, 01:57 PM
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Default RE: do ailerons provide lift?

Since the original question as to whether ailerons add to the lift in nuetral has been answered quite well (Yes they do as they are a part of the wing area, regardless of gaps, etc).........

Iam going to look at this "elevator during turn" again.

Quote:
Why "slight"? In a 45 degree bank, you'd get about the same contribution to tightening the turn as you would to raising the nose, wouldn't you? In an 80 degree bank, you'd get more contribution to the turn than to up. And while you would certainly get additional lift, additional lift is what you want if you are turning more tightly, isn't it?
Yes, you are right. Iguess I didn't make it clear enough in my first posts ( I was posting from work yesterday). I agree, the elevator will tighten the turn a bit due to the horizontalvector. Beyond 45°, it will do more turn tightening than nose up, that is true. (I believe somewhere in my first post I said something about that, just maybe not clear enough) BUT, that being said, the primary reason for using the elevator in the turn is to hold the nose up. Again, you take a couple flight lessons in full size and you will quickly learn that. Even in turns with banks angles of more than 45°. One of the excersizes early on in flight training is steep turns, ie: 60° bank. Even then, the lesson is to hold constant bank angle, and maintain altitude with elevator. Let the turn radius sort itself out. The primary use of elevator in a turn SHOULDBE, to keep the nose up, NOT to turn tighter. While it does work, if you are just yanking to try and tighten up the turn, you are doing it wrong. People have been killed by trying to do this in full scale aircraft when slowed down and turning from baseto final approach.....theturn is overshooting the runway so they pull backto force it around and boom, stal, spin, crash.Now, with R/C airplanes, we can get away with it because our wing loadings are low enough and power/weight ratios high enough, so most guys fly this way. And it works fine......untilyou get into a high wingloading, lower power/weightratiowarbird or some such scale airplane.

When Ifly R/C, I tend to fly smooth and gentle, same as I would in a full scale. Only when Iam horsing around do I use banks of more than 45°. Ialso teach my students to fly this way, rather than a "bank and yank" style of flying. The reason being, not only does it prevent the "split S" issue brought up earlier, but it also prevents stalling due to the increased load factor (Bax mentioned this). Ihave seen more guys stall due to pulling too hard in a turn than Ihave seen "over-bank" and split S into the ground, especially with the larger, heavier airplanes. Get guys into the habit of turning gently and properly right from the start.

So, while it is entirely true that more elevator DOES help tighten the turn, especially in steeper than 45° banks....that is NOTthe way it should be used. Elevator is to maintain altitude, bank angle controls turn rate. (In reality, the turn radius also depends on wind direction and strength, and airspeed. ie: an airplane in a 45° bank will have a smaller turn radius at 100mph than at 200mph.)
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Old 01-11-2013, 02:29 PM
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Default RE: do ailerons provide lift?


Quote:
ORIGINAL: rhall999

Since the original question as to whether ailerons add to the lift in nuetral has been answered quite well (Yes they do as they are a part of the wing area, regardless of gaps, etc).........

I am going to look at this ''elevator during turn'' again.

Quote:
Why ''slight''? In a 45 degree bank, you'd get about the same contribution to tightening the turn as you would to raising the nose, wouldn't you? In an 80 degree bank, you'd get more contribution to the turn than to up. And while you would certainly get additional lift, additional lift is what you want if you are turning more tightly, isn't it?
Yes, you are right. I guess I didn't make it clear enough in my first posts ( I was posting from work yesterday[img][/img]). I agree, the elevator will tighten the turn a bit due to the horizontal vector. Beyond 45°, it will do more turn tightening than nose up, that is true. (I believe somewhere in my first post I said something about that, just maybe not clear enough) BUT, that being said, the primary reason for using the elevator in the turn is to hold the nose up. Again, you take a couple flight lessons in full size and you will quickly learn that. Even in turns with banks angles of more than 45°. One of the excersizes early on in flight training is steep turns, ie: 60° bank. Even then, the lesson is to hold constant bank angle, and maintain altitude with elevator. Let the turn radius sort itself out. The primary use of elevator in a turn SHOULD BE, to keep the nose up, NOT to turn tighter. While it does work, if you are just yanking to try and tighten up the turn, you are doing it wrong. People have been killed by trying to do this in full scale aircraft when slowed down and turning from base to final approach.....the turn is overshooting the runway so they pull back to force it around and boom, stal, spin, crash. Now, with R/C airplanes, we can get away with it because our wing loadings are low enough and power/weight ratios high enough, so most guys fly this way. And it works fine......until you get into a high wingloading, lower power/weight ratio warbird or some such scale airplane.

When I fly R/C, I tend to fly smooth and gentle, same as I would in a full scale. Only when I am horsing around do I use banks of more than 45°. I also teach my students to fly this way, rather than a ''bank and yank'' style of flying. The reason being, not only does it prevent the ''split S'' issue brought up earlier, but it also prevents stalling due to the increased load factor (Bax mentioned this). I have seen more guys stall due to pulling too hard in a turn than I have seen ''over-bank'' and split S into the ground, especially with the larger, heavier airplanes. Get guys into the habit of turning gently and properly right from the start.

So, while it is entirely true that more elevator DOES help tighten the turn, especially in steeper than 45° banks....that is NOT the way it should be used. Elevator is to maintain altitude, bank angle controls turn rate. (In reality, the turn radius also depends on wind direction and strength, and airspeed. ie: an airplane in a 45° bank will have a smaller turn radius at 100mph than at 200mph.)
Guess it depends on how you like to fly.
I like to fly around at 90 degree bank angle (knife-edge).
Elevator doesn't do me much good for keeping the nose up in that situation.
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Old 01-11-2013, 02:53 PM
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Default RE: do ailerons provide lift?

Lol! Elvis (the OP) left the building back at post #14.
Still, a good discussion.
Some here(Hossfly and myself, maybe others?)have been flying full-scale for many years, in my case 36, 30 as a CFI. Langewiesche's book is a bible, as is 'Aerodynamics for Naval Aviators' for advanced discussions.
First: ailerons add to the total wing area and are used by engineers to compute lift so, yes, they do contribute to lift. Sorry, Gary Harris.
Second: adding elevator with any bank beyond 45-degrees will increase turn rate more than increase altitude. By the same token, increasing elevator with a bank angle below 45-degrees wil increase altitude more than turn rate.
Third: in a full-scale during steep turns (we'll say 60-degrees), if altitude loss occurs the correct procedure is to reduce bank angle slightly while maintaining back-pressure (elevator) or increase elevator slightly then, when altitude is regained, increase bank angle slightly. Thus, just 'hauling back' on the elevator alone is a crude way to maintain altitude.
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Old 01-11-2013, 02:59 PM
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Default RE: do ailerons provide lift?

Quote:
"Adding elevator" means what exactly? That you added elevators to the stab?
Sure. Excessive literalism can be a symptom of serious underlying conditions. You might want to check.
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Old 01-11-2013, 03:08 PM
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Default RE: do ailerons provide lift?

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Third: in a full-scale during steep turns (we'll say 60-degrees, if altitude loss occurs the correct procedure is to reduce bank angle slightly while maintaining back-pressure (elevator) or increase elevator slightly then, when altitude is regained, increase bank angle slightly. Thus, just 'hauling back' on the elevator alone is a crude way to maintain altitude.
Thanks for mentioning this Eddie. Ihad thought about mentioning varying bank angle when tying my last post, but then left it out in favour of trying tokeep the discussion a bit simpler....so I left it at just the elevator portion. Perhaps in retrospect Ishould have described it appropriately the first time. My instructor did teach me the correct technique of adjusting bank a little bit as needed though.

Ijust wish I could get out and fly more, both full scale and r/c. Right now we have roughly 5 ft of snow on the ground, temperature of -20°C, and today we even had less than 2 miles visibility in ice fog. Not much flying happens in this crappy weather.
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Old 01-11-2013, 04:43 PM
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Default RE: do ailerons provide lift?



If the ailerons are tapered they add lift. If the aileron is a flat plank I'd say no lift, just wing area. If the aileron is not in the neutral position, it adds drag to the airfoil... Is drag considered lift?

Do I know for sure? Nope.

I love this hobby...[8D]

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Old 01-11-2013, 05:16 PM
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Default RE: do ailerons provide lift?

Quote:
ORIGINAL: brockettman



If the ailerons are tapered they add lift. If the aileron is a flat plank I'd say no lift, just wing area. If the aileron is not in the neutral position, it adds drag to the airfoil... Is drag considered lift?

Do I know for sure? Nope.

I love this hobby...[8D]

Finally!

I just looked at two the of planes I am building, and neither of them have tapered ailerons meaning that they are thinner at the trailing edge furthering the airfoil to the total wing chord.
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Old 01-11-2013, 05:54 PM
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Default RE: do ailerons provide lift?


Quote:
ORIGINAL: eddieC

Lol! Elvis (the OP) left the building back at post #14.
Still, a good discussion.
Some here (Hossfly and myself, maybe others?) have been flying full-scale for many years, in my case 36, 30 as a CFI. Langewiesche's book is a bible, as is 'Aerodynamics for Naval Aviators' for advanced discussions.
First: ailerons add to the total wing area and are used by engineers to compute lift so, yes, they do contribute to lift. Sorry, Gary Harris. [img][/img]
Second: adding elevator with any bank beyond 45-degrees will increase turn rate more than increase altitude. By the same token, increasing elevator with a bank angle below 45-degrees wil increase altitude more than turn rate.
Third: in a full-scale during steep turns (we'll say 60-degrees), if altitude loss occurs the correct procedure is to reduce bank angle slightly while maintaining back-pressure (elevator) or increase elevator slightly then, when altitude is regained, increase bank angle slightly. Thus, just 'hauling back' on the elevator alone is a crude way to maintain altitude.
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Old 01-11-2013, 05:57 PM
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Default RE: do ailerons provide lift?


Quote:
ORIGINAL: eddieC

Lol! Elvis (the OP) left the building back at post #14.
Still, a good discussion.
Some here (Hossfly and myself, maybe others?) have been flying full-scale for many years, in my case 36, 30 as a CFI. Langewiesche's book is a bible, as is 'Aerodynamics for Naval Aviators' for advanced discussions.
First: ailerons add to the total wing area and are used by engineers to compute lift so, yes, they do contribute to lift. Sorry, Gary Harris. [img][/img]
Second: adding elevator with any bank beyond 45-degrees will increase turn rate more than increase altitude. By the same token, increasing elevator with a bank angle below 45-degrees wil increase altitude more than turn rate.
Third: in a full-scale during steep turns (we'll say 60-degrees), if altitude loss occurs the correct procedure is to reduce bank angle slightly while maintaining back-pressure (elevator) or increase elevator slightly then, when altitude is regained, increase bank angle slightly. Thus, just 'hauling back' on the elevator alone is a crude way to maintain altitude.

Eddie, I'd still like to see proof where ailerons provide lift that don't follow the wings airfoil and of equal wing chord.
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Old 01-11-2013, 06:17 PM
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Default RE: do ailerons provide lift?


Quote:
ORIGINAL: Top_Gunn

Quote:
"Adding elevator" means what exactly? That you added elevators to the stab?
Sure. Excessive literalism can be a symptom of serious underlying conditions. You might want to check.
Ignorance is bliss, huh!
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Old 01-11-2013, 06:24 PM
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Default RE: do ailerons provide lift?


Quote:
ORIGINAL: brockettman



If the ailerons are tapered they add lift. If the aileron is a flat plank I'd say no lift, just wing area. If the aileron is not in the neutral position, it adds drag to the airfoil... Is drag considered lift?

Do I know for sure? Nope.

I love this hobby...[8D]

Quote:
Edited by Moderator

LOL,

Wing area tapered or constant = lift, if you don't think so, just remove that wing from that airplane of yours either type wing and go fly that bad boy, then let us know how that worked out for you...

Bob
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Old 01-11-2013, 06:42 PM
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Default RE: do ailerons provide lift?

Probably won't work without a wing... It's about the aileron not the wing. Doesn't there have to be some kind of taper or airfoil to create a difference in air pressure? The variation in the tapered aileron might be miniscule, but it still matters, doesn't it?

OOPS! now I'm part of the fire drill!

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Old 01-11-2013, 06:52 PM
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Default RE: do ailerons provide lift?

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Eddie, I'd still like to see proof where ailerons provide lift that don't follow the wings airfoil and of equal wing chord. 

I'm no aerodynamicist, Gary, but I do know ailerons are figured into total wing area, both full-size and models. Do you think all lift ends at the wing trailing edge? That won't fly, will it?

We've presented the 'Stick and Rudder' book. I'll turn the question around: prove that ailerons aren't producing lift. Use Google, Wiki, library, etc. Does it seem counter-intuitive to you? If so, I understand. Sometimes some principles seem like that. The theory of lift, Bernoulli's principle, things like that can seem odd. I teach my students it's a combination of Bernoulli (air going over the top of the wing goes faster, reducing pressure, so the wings lifts), and angle-of-attack (wing is pitched up, air is deflected down, equal & opposite reaction like 'flying' your hand out of a car window). Thats also how foamies with flat wings fly with no airfoil, angle of attack, very little Bernoulli. 

Do the ailerons provide the same lift in a turn? I'd be guessing to say 'yes', because they're opposing each other; one creates lift (the downward aileron), and the other kills lift (though not as much as you might think). Some gliders can 'reflex' their ailerons, both go up a little. This can make them more efficient, help them go faster depending on weight & CG, etc. I have an Ultra Stick 40 with flaperons that can go up or down, the ailerons and flaps move in the same direction using a dial on my tx. Aileron stick still works normal. 

Here's something else: the ailerons are used only at the beginning and end of a turn, not during except for minor adjustments. Once the turn is initiated and bank angle is reached, they should go back to neutral. No plane is perfect tho; some like a little aileron held in the turn, but many like a bit of opposite aileron during the turn. A thing called 'over-banking tendency'. 

If you want to believe ailerons don't provide lift, you're flying in the face of a lot of teachings of a lot of guys with a lot of letters after their names. [8D]
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Old 01-11-2013, 07:17 PM
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Default RE: do ailerons provide lift?

The airfoil does not need any taper (the correct term is chamber) to create lift. Proof......look at all the foamies with a simple flat plate wing. They still fly don't they, those wings are still producing lift. Whether the aileron is tapered or just a flat plate attached to the back of the wing does not matter. As long as they add to the total wing area, they will contribute to the lift produced. Flat plate type ailerons might be a little less efficient than a tapered one tha continues the airfoil shape, but they will still work the same.

It is really simple guys.....increasing the total wing area increases the lift produced. A simple study of basic aerodynamics will prove this. It doesn't matter if the additional wing area is airfoil shaped or flat.
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Old 01-11-2013, 07:20 PM
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Default RE: do ailerons provide lift?

Quote:
ORIGINAL: brockettman

Probably won't work without a wing... It's about the aileron not the wing. Doesn't there have to be some kind of taper or airfoil to create a difference in air pressure? The variation in the tapered aileron might be miniscule, but it still matters, doesn't it?

OOPS! now I'm part of the fire drill!

Ben
Lets see here, it's about the aileron not the wing ha, try to get your head wrapped this, the aileron in fact becomes part of the wing, adding the aileron adds wing area and adding wing area adds lift.

Bob
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Old 01-11-2013, 07:28 PM
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Default RE: do ailerons provide lift?

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Doesn't there have to be some kind of taper or airfoil to create a difference in air pressure? The variation in the tapered aileron might be miniscule, but it still matters, doesn't it?

If that were true, our flat-plate foamies and aircraft with symmetrical airfoils wouldn't fly. Fortunately they never got that memo.  Bernoulli isn't everything. Angle of attack also has to be figured in. It's a combination of both. 
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Old 01-11-2013, 07:37 PM
  #49
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Default RE: do ailerons provide lift?

Not exactly answering the org question but two cases.

I know from experience when you loose an aileron due to flutter on 3rd flight, as I did on my top flight P-39 (years ago) you loose lift!
I immediately lost wing area and thus lift on that side. She rolled quickly but I saved with full opposite rudder and aileron to make about half a circuit wings level. Well it was a short lived save as I made the mistake if throttle back just to 1/2 and suddenly she snapped rolled in from 50 ft.

When I had a servo arm come off one wings aileron, the plane appeared to have the same lift, it just felt really sluggish. Flew for about 5 more minutes but just didn have the normal,performance. Aileron was free wheeling with the wind and not "neutral" as if fixed to the wing, so it just kinda made the approach in with that particular wing a little low like maybe 5 degrees and a normal landing. Thus that wing did actually loose some lift.

So two lessons learned. 1: speed is life. 2: preflight you airplane after every flight.
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Old 01-11-2013, 07:40 PM
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Default RE: do ailerons provide lift?

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ORIGINAL: jetmech05

You'll notice that the down aileron will add lift like a flap, while the up aileron will kill lift like a spoiler. So yes at neutral they add to the wing area. And add and kill lift while in use. This is why you need a touch of elevator to compensate for the loss of lift
This is incorrect.

Ailerons do NOT "kill" lift. Ailerons CHANGE the AOA. You are somewhat describing a roll spoiler. The REASON that you need to add up elevator to maintain altitude is because you have transitioned your vertical lift component towards the horizontal plain which is why the plane turns. Now you need to ADD vertical component to make up for the lost lift from the bank.



But hey I only have a little over 15,000 hours of flight time. What would I know.
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