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  1. #1

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    do ailerons provide lift?

    I was looking at my partialy completed plane and noticed how much larger the wing looks when I hold the ailerons up to it. (they are not installed yet). I understand the function of the ailerons is to control or direct the air flow ( i guess), but does it provide lift when in the nuetral state?

  2. #2
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    RE: do ailerons provide lift?

    Aileron contribute to the overall wing area so yes they do contribute to lift as well.
    Of course it's true, I read it on the Internet.

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    RE: do ailerons provide lift?

    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

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    RE: do ailerons provide lift?

    I will add this. I was looking at the instruction manual for a GP Dazzler 40 yesterday. In the final trim section, they discussed the affect that ailerons have on lift. The manual discusses trim settings for aileron throw.

    Aileron Rigging: With wings level, pull to a vertical climb and neutralize the controls. If the climb continues along the same path, the trim is correct. If the nose tends to go to an inside loop, raise both ailerons very slightly. If the nose tends to go to an outside loop, lower both ailerons very slightly.
    So, to answer the original question, do the ailerons provide lift in the neutral state, well, yes the ailerons do indeed provide overall lift because they are part of the wing. When the plane is flying straight and level, the wing provides the necessary lift at a particular airspeed to fly straight and level. So, being part of the wing, yes, they do provide lift.

    CGr.
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    RE: do ailerons provide lift?

    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
    Yes. Another reason you need elevator in a turn is to turn the plane. Visualize a plane that's banked, which is how it will be flying after you use the ailerons. To turn the nose toward the direction you want to turn you need some up elevator.

    This isn't just a trivial point about how airplanes fly; it has a practical application. If you are making a tight turn and you need to make it tighter (to stay in front of the flight line, for instance), you tighten the turn by using more up elevator. Beginners sometimes try to do it by adding aileron or rudder, and the usual result is to add to the roll, sometimes leading to an unintentional split S. Planes get broken that way.
    Al Gunn
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    RE: do ailerons provide lift?

    If we want to be technical about it we need the up elevator to maintain altitude because when we bank the plane we are using some of our lift for turning. Since a portion of the lift we were using to fly straight and level is now being used to push the plane to one side, there isn't enough anymore to maintain altitude. So turning requires the wing to make more overall lift, thus the change in how much elevator is required to maintain a constant altitude.
    No kid, I said break ground and fly into the wind!

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    RE: do ailerons provide lift?


    ORIGINAL: jester_s1

    If we want to be technical about it we need the up elevator to maintain altitude because when we bank the plane we are using some of our lift for turning. Since a portion of the lift we were using to fly straight and level is now being used to push the plane to one side, there isn't enough anymore to maintain altitude. So turning requires the wing to make more overall lift, thus the change in how much elevator is required to maintain a constant altitude.
    That's true. But it's also true that up elevator is needed to turn when banked. It does two useful things in turns, not just one. As you said, the banked wing "pushes" the plane sideways. Some up elevator helps convert that push to a turn. Trying to tighten a turn by using just more aileron doesn't work, and not just because it loses altitude. This is why Langewiesche disliked the term "elevator." He called them "flippers," which didn't catch on.
    Al Gunn
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    RE: do ailerons provide lift?

    In a turn, elevator is used to maintain the altitude. The bank is what turns the airplane. If you use no elevator, the airplane will turn, but also descend. The more bank, the tighter the turn, and the steeper the descent. That's it.

    For a thorough discussion on how airplanes fly from a practical, pilot's perspective, please see the book, "Stick and Rudder" by Wolfgang Langeweische. An aviation classic that makes things eminently clear. The principles hold for models in addition to full-size aircraft.
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    RE: do ailerons provide lift?


    ORIGINAL: chadxp1

    I was looking at my partialy completed plane and noticed how much larger the wing looks when I hold the ailerons up to it. (they are not installed yet). I understand the function of the ailerons is to control or direct the air flow ( i guess), but does it provide lift when in the nuetral state?
    1. Draw yourself an airfoil. Now draw a straight line between the absolute farterest poins, the Leading Edge and the Trailing Edge. That is your Chord Line.

    2. When there is air-flow about the wing, there is a change of total (static + dynamic) pressure around the airfoil. Airflow increases dynamic pressure. Static pressure remains the same and thus LIFT is increased. Lift is a function of air-mass density x angle of attack(AOA) x 1/2 of velocity squared, X surface area. Notice the item AOA which is the difference between the free air flow and the CHORD LINE of the wing.

    3. Ailerons are part of the surface area. Therefore they contribute to Total Lift function.

    4. Draw yourself an airplane fuse, going away, wing, tail, just a circle with lines extended to emulate wings and stab and vertical stab. Draw an arrow straight up over the fuse.. That is "Lift" in straight flight. Draw another line straight down of equal length. That is weight (gravity, whatever) Now draw another line of same length in a bank angle, let's use 60 degrees. Notice the straight down line will be the same. Now make a right triangle of the UP line. It now has a short length of UP. That is the applied lift against gravity. The long line is the force of the lift vector pulling the airplane in the turn. The pilot now has to increase up elevator to lengthen the "up" line so the lift equals the gravity line down.
    To maintain level flight at a given speed, lift will equal weight (gravity called 1 G). In a 60 degree bank the applied elevator force has to provide 2 Gs (twice the gravity).
    Since the increase of elevator loads the wing to provide additional lift, it also increases drag using the same formula. Therefore to maintain the same altitude and airspeed to keep the lift formula satisfied, will create a need for more AOA and thrust.

    5. A pilot has no control over air mass density nor the weight at that time. He has control over AOA and thrust. As an RC sport-pilot, you only need to consider those two functions.
    a. More wing area, less weight effect, flies better. More speed, more lift, pilot can slow down or trim nose-down to reduce AOA.
    b. In bank, if you slow, you need considerably more AOA. If you get too much AOA, the static pressure air can separate from wing surface, and model stalls. Level wings, Increase SPEED, then gently apply elevator up to recover. BTW, stalls can happen at ANY airspeed, NOT just slow. Pilots practice such.
    c. Airspeed - velocity is the main character in the lift equation. You can increase it by decreasing AOA , nosing down or adding power. You can decrease it by any opposite to increase.

    AILERONS: Can be set to perform many functions. On other than symetrical wing airfoils, 2-5 degrees up on each makes for a much better flying machine. 1-3 doesn;t hurt for sym. airfoils depending on the use of the model. Your choice. That is a whole 'nother lesson plan!!

    Please pardon typos. Need to go!
    I FLY airplanes not computers!!

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  10. #10
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    RE: do ailerons provide lift?

    Ill have to go against the grain here. Ailerons add to the total wing chord yes, but I don't see how they add lift. It's my understanding that the airfoil creates a Delta P (pressure differential) and that causes lift. Any effect that a down aileron would create for lift for that side would be negated by the opposing aileron creating down force.

    I think.

    Edit: Hossfly explains it.

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  11. #11
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    RE: do ailerons provide lift?

    After thinking about it for a minute, I'm going back to my original answer and say no. The ailerons themselves do not create lift and in some cases, may create down force depending the plane due to turbulent flow over the gaps between the ailerons between the trailing edge of the wing and the ailerons. Now if you build two wings, one with ailerons, and another without ailerons , but of equal wing chord, I don't see how having ailerons would create any more lift than the wing built with ailerons. So I'm still saying no.
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    RE: do ailerons provide lift?

    do ailerons provide lift?
    About half the time.
    - Supplementary insipid innocuous inane vacuous proclamation

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    RE: do ailerons provide lift?

    ORIGINAL: Bax

    In a turn, elevator is used to maintain the altitude. The bank is what turns the airplane. If you use no elevator, the airplane will turn, but also descend. The more bank, the tighter the turn, and the steeper the descent. That's it.

    For a thorough discussion on how airplanes fly from a practical, pilot's perspective, please see the book, ''Stick and Rudder'' by Wolfgang Langeweische. An aviation classic that makes things eminently clear. The principles hold for models in addition to full-size aircraft.
    NASA disagrees: "During a banked turn, elevator inputs can increase the lift and cause a tighter turn. That is why elevator performance is so important for fighter aircraft." http://www.grc.nasa.gov/WWW/k-12/airplane/elv.html

    And Langewiesche, p. 198: "An airplane is turned by laying it over on its side and lifting it around through back pressure on the stick." (In "Stick and Rudder," this whole sentence is in italics.)

    You are of course right to say that you need elevator in a turn to keep the nose from dropping. But you also use elevator to tighten a turn.
    Al Gunn
    Ultra Sport Brotherhood No. 9

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    RE: do ailerons provide lift?

    thank you everyone for the information. good stuff. i really like that link to the nasa website. pretty cool.

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    RE: do ailerons provide lift?

    In reply to the original question, yes ailerons do provide lift just because they are a part of the wing area, and especiallywhen they are deflected down. But not when deflected up, then they reduce lift, but....this has already been discussed enough.

    Draw yourself an airplane fuse, going away, wing, tail, just a circle with lines extended to emulate wings and stab and vertical stab. Draw an arrow straight up over the fuse.. That is "Lift" in straight flight. Draw another line straight down of equal length. That is weight (gravity, whatever) Now draw another line of same length in a bank angle, let's use 60 degrees. Notice the straight down line will be the same
    Below is a drawing such as the one Hossfly is talking about....have a good look at it.

    Now I am going to pick on poor Top_Gunn for a bit (sorry Top) (NOTE: For the following, it is important to remember, the WEIGHT of the airplane does not change....fuel burn during a simple turn is negligible).

    That's true. But it's also true that up elevator is needed to turn when banked. It does two useful things in turns, not just one. As you said, the banked wing "pushes" the plane sideways. Some up elevator helps convert that push to a turn
    .

    This is not totally correct. While there is a sideways "push" do to the banked wing, which you can see in the drawing below, the tail surfaces, in particular the vertical fin, causes the airplane to turn when it trys to fly "sideays". You do not need elevator to convert that "push" into a turn, the design of the airplane tail will do it by itself. On many aircraft a touch or rudder is needed to help it turn, but that is usually do to adverse yaw...a whole seperate turning issue. In actual practice, the elevator is used to keep the nose up and prevent altitude loss, not to "turn" the airplane.

    This isn't just a trivial point about how airplanes fly; it has a practical application. If you are making a tight turn and you need to make it tighter (to stay in front of the flight line, for instance), you tighten the turn by using more up elevator. Beginners sometimes try to do it by adding aileron or rudder, and the usual result is to add to the roll, sometimes leading to an unintentional split S. Planes get broken that way.
    In your example of tightening the turn to stay on front of the flightline, simply adding elevator as you say is also going to cause a broken airplane. In a steady turn at a set bank angle, adding elevator will cause the aircraft to pitch up...NOT turn tighter, and may lead to a stall. In reality, if you want to turn tighter, you need to increase bank angle. Of course, the increase in bank angle will require more elevator as well, but again, it is to keep the aircraft from losing altitude, and not to turn. We will see why in my next point.

    NASA disagrees: "During a banked turn, elevator inputs can increase the lift and cause a tighter turn. That is why elevator performance is so important for fighter aircraft." http://www.grc.nasa.gov/WWW/k-12/airplane/elv.html

    And Langewiesche, p. 198: "An airplane is turned by laying it over on its side and lifting it around through back pressure on the stick." (In "Stick and Rudder," this whole sentence is in italics.)

    You are of course right to say that you need elevator in a turn to keep the nose from dropping. But you also use elevator to tighten a turn.
    While these are both correct statements, you are missing an important statement there, the "increase the lift" part. Lets look at why that is important.

    Now, go and have another look at the diagram. You will see that when the airplane is straight and level, the lift equals the weight. Alsonote that the lift is always perpendicular to the wings. But, when the airplane is put into a bank, the lift vector tilts to the same angle as the bank angle. Now, the lift vector can be split into two vectors, one vertical and one horizontal. The vertical one is what is opposing the weight of the aircraft, and the horizontal one is what is giving that "sideways push" discussed earlier. Here is the issue though:

    Because the total lift is "split" between the two vectors, the vertical lift vector is reduced. That means that the weight now exceeds the amount of lift holding the airplane up, remember, the weight doesn't change. In order to get that lift back, we need to increase either airspeed or angle of attack. Increasing angle of attack is the most practical, especially in full size aircraft that do not have gobs of extra power. So, we increase angle ofattack, and the way to do that is to pull back on the stick (up elevator). This increases the total lift vector, which allows the vertical component to again equal the weight. Now, looking at that diagram again, you can see how in a set angle of bank, simply applying up elevator will cause the airplane to climb. There will be a small increase in the horizontal component too, but in a "normal" turn, not enough to even notice the increase in turn radius.

    BUT, look what happens if we steepen the bank further. Now, the total lift vector is still being split, but the steeper the bank, the more of the lift is given to the horizontal vector. This will cause a tighter turn. (Remember, the tail area will cause the airplane to "yaw" when that horizontal lift "pushes" us sideway, thus turning the airplane.) So, now we havea large portion of our lift going to the horizontal vector and less to the vertical vector, now the airplane really wants to drop, so we need to increase the total lift a lot more. So, to do this we need to pull back some more to increase the angle of attack enough to increase the total lift to increase the vertical component to keep us up in the sky. Whew, lots going on here isn't there.

    So, as we can see, the more we increase the bank, the quicker we will turn. But at the same time, the faster we will drop unless we pull back more to mainain enough lift to hold the airplane up. We can also visualise that for a set bank angle, and a set airspeed, there will be a set angle of attack that the wings need in order to produce enough lift to hold the airplane up while some of the lift is being "stolen" to turn the airplane. There will come a point where the elevator will become the primary "turning" control, but not until a nearly vertical bank. Until then, we still need to hold the airpalne in the air, and that is the job of the wings. They need to continue to produce enough "vertical" lift to overcome the weight.

    Sorry if I "stepped on your toes" Top_Gunn. Just hoping to help with a bit of understanding.
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    RE: do ailerons provide lift?

    Now, can Ipick on GarryHarris? (Sorry Gary)

    Now if you build two wings, one with ailerons, and another without ailerons , but of equal wing chord, I don't see how having ailerons would create any more lift than the wing built with ailerons. So I'm still saying no.
    Your test will not really tell you to much. Both wings being equal chord, they will fly so close to the same that you will not be able to discern the difference. If anything, there will be a small increase in drag on the aileron equipped wing due to the gap, but that is about it.

    If you would really like to see the difference in the lift made by the ailerons, just build one wing. Build it with the ailerons and go fly it. Fly it a few times to get used to the way it flies, and then cut the ailerons off, and go fly it again. That will tell you what difference the ailoerons make.

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    RE: do ailerons provide lift?

    ORIGINAL: rhall999

    In reply to the original question, yes ailerons do provide lift just because they are a part of the wing area, and especiallyΒ*when they are deflected down.Β* But not when deflected up, then they reduce lift, but....this has already been discussed enough.

    Draw yourself an airplane fuse, going away, wing, tail, just a circle with lines extended to emulate wings and stab and vertical stab. Draw an arrow straight up over the fuse.. That is ''Lift'' in straight flight. Draw another line straight down of equal length. That is weight (gravity, whatever) Now draw another line of same length in a bank angle, let's use 60 degrees. Notice the straight down line will be the same
    Below is a drawing such as the one Hossfly is talking about....have a good look at it.

    Now I am going to pick on poor Top_Gunn for a bitΒ*Β* (sorry Top)Β* (NOTE:Β* For the following, it is important to remember, the WEIGHT of the airplane does not change....fuel burn during a simple turn is negligible).

    That's true. But it's also true that up elevator is needed to turn when banked. It does two useful things in turns, not just one. As you said, the banked wing ''pushes'' the plane sideways. Some up elevator helps convert that push to a turn
    .

    This is not totally correct.Β* While there is a sideways ''push'' do to the banked wing, which you can see in the drawing below, the tail surfaces, in particular the vertical fin, causes the airplane to turn when it trys to fly ''sideays''.Β* You do not need elevator to convert that ''push'' into a turn, the design of the airplane tail will do it by itself.Β* On many aircraft a touch or rudder is needed to help it turn, but that is usually do to adverse yaw...a whole seperate turning issue.Β* In actual practice, the elevator is used to keep the nose up and prevent altitude loss, not to ''turn'' the airplane.

    This isn't just a trivial point about how airplanes fly; it has a practical application. If you are making a tight turn and you need to make it tighter (to stay in front of the flight line, for instance), you tighten the turn by using more up elevator. Beginners sometimes try to do it by adding aileron or rudder, and the usual result is to add to the roll, sometimes leading to an unintentional split S. Planes get broken that way.
    In your example of tightening the turn to stay on front of the flightline, simply adding elevator as you say is also going to cause a broken airplane.Β* In a steady turn at a set bank angle, adding elevator will cause the aircraft to pitch up...NOT turn tighter, and may lead to a stall.Β* In reality, if you want to turn tighter, you need to increase bank angle.Β* Of course, the increase in bank angle will require more elevator as well, but again, it is to keep the aircraft from losing altitude, and not to turn.Β* We will see why in my next point.

    NASA disagrees: ''During a banked turn, elevator inputs can increase the lift and cause a tighter turn. That is why elevator performance is so important for fighter aircraft.'' http://www.grc.nasa.gov/WWW/k-12/airplane/elv.html

    And Langewiesche, p. 198: ''An airplane is turned by laying it over on its side and lifting it around through back pressure on the stick.'' (In ''Stick and Rudder,'' this whole sentence is in italics.)

    You are of course right to say that you need elevator in a turn to keep the nose from dropping. But you also use elevator to tighten a turn.
    While these are both correct statements, you are missing an important statement there, the ''increase the lift'' part.Β* Lets look at why that is important.

    Now, go and have another look at the diagram.Β* You will see that when the airplane is straight and level, the lift equals the weight.Β* AlsoΒ*note that the lift is always perpendicular to the wings.Β* But, when the airplane is put into a bank, the lift vector tilts to the same angle as the bank angle.Β* Now, the lift vector can be split into two vectors, one vertical and one horizontal.Β* The vertical one is what is opposing the weight of the aircraft, and the horizontal one is what is giving that ''sideways push'' discussed earlier.Β* Here is the issue though:

    Because the total lift is ''split'' between the two vectors, the vertical lift vector is reduced.Β* That means that the weight now exceeds the amount of lift holding the airplane up, remember, the weight doesn't change.Β* In order to get that lift back, we need to increase either airspeed or angle of attack.Β* Increasing angle of attack is the most practical, especially in full size aircraft that do not have gobs of extra power.Β* So, we increase angle ofΒ*attack, Β*and the way to do that is to pull back on the stick (up elevator).Β* This increases the total lift vector, which allows the vertical component to again equal the weight.Β* Now, looking at that diagram again, you can see how in a set angle of bank, simply applying up elevator will cause the airplane to climb.Β* There will be a small increase in the horizontal component too, but in a ''normal'' turn, not enough to even notice the increase in turn radius.

    BUT, look what happens if we steepen the bank further.Β* Now, the total lift vector is still being split, but the steeper the bank, the more of the lift is given to the horizontal vector.Β* This will cause a tighter turn.Β* (Remember, the tail area will cause the airplane to ''yaw'' when that horizontal lift ''pushes'' us sideway, thus turning the airplane.)Β* So, now we havea large portion of our lift going to the horizontal vector and less to the vertical vector, now the airplane really wants to drop, so we need to increase the total lift a lot more.Β* So, to do this we need to pull back some more to increase the angle of attack enough to increase the total lift to increase the vertical component to keep us up in the sky.Β* Whew, lots going on here isn't there.Β*

    So, as we can see, the more we increase the bank, the quicker we will turn.Β* But at the same time, the faster we will drop unless we pull back more to mainain enough lift to hold the airplane up.Β* We can also visualise that for a set bank angle, and a set airspeed, there will be a set angle of attack that the wings need in order to produce enough lift to hold the airplane up while some of the lift is being ''stolen'' to turn the airplane.Β* There will come a point where the elevator will become the primary ''turning'' control, but not until a nearly vertical bank.Β* Until then, we still need to hold the airpalne in the air, and that is the job of the wings.Β* They need to continue to produce enough ''vertical'' lift to overcome the weight.

    Sorry if I ''stepped on your toes'' Top_Gunn.Β* Just hoping to help with a bit of understanding.
    I don't really disagree with any of your argument, but you're leaving things out. When you increase the angle of attack of a plane that's banked, some of the increase keeps you from dropping and some of it makes you turn tighter because, as you say, the lift vector is not vertical. If you are banked 45 degrees, which isn't unusual for a model, about half the angle of attack increase contributes to the the turn. If you're banked 85 degrees, most of it does. Langewiesche points out somewhere that an elevator laid on its side wouldn't take you any higher. Same, in part, when it's partly on its side. To put it another way, when you "increase the lift" with elevator when the plane is banked, part of that lift is turning the plane, not keeping it away from the ground, because the lift vector is no longer vertical.

    A recurring problem with beginners is that they start a turn, decide they need to turn more sharply, add aileron, and before they realize what's up they're banked more than 90 degrees and their up elevator is now pointing the nose toward the ground. The split S is one manouver all beginners can do, usually accidentally. When I tell them to tighten their turns with elevator, the problem goes away. (I also try to get them not to bank so much, but sometimes you have to.)
    Al Gunn
    Ultra Sport Brotherhood No. 9

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    RE: do ailerons provide lift?

    I don't really disagree with any of your argument, but you're leaving things out. When you increase the angle of attack of a plane that's banked, some of the increase keeps you from dropping and some of it makes you turn tighter because, as you say, the lift vector is not vertical. If you are banked 45 degrees, which isn't unusual for a model, about half the angle of attack increase contributes to the the turn. If you're banked 85 degrees, most of it does.
    Hi Top, well, I did mention it in there actually:

    This increases the total lift vector, which allows the vertical component to again equal the weight. Now, looking at that diagram again, you can see how in a set angle of bank, simply applying up elevator will cause the airplane to climb. There will be a small increase in the horizontal component too, but in a ''normal'' turn, not enough to even notice the increase in turn radius.

    BUT, look what happens if we steepen the bank further. Now, the total lift vector is still being split, but the steeper the bank, the more of the lift is given to the horizontal vector. This will cause a tighter turn. (Remember, the tail area will cause the airplane to ''yaw'' when that horizontal lift ''pushes'' us sideway, thus turning the airplane.) So, now we have a large portion of our lift going to the horizontal vector and less to the vertical vector, now the airplane really wants to drop, so we need to increase the total lift a lot more. So, to do this we need to pull back some more to increase the angle of attack enough to increase the total lift to increase the vertical component to keep us up in the sky. Whew, lots going on here isn't there.
    I fly full scale as well as models, and the result of using elevator in a turn is VERYeasy to see in a full size when you can physically feel and see out the windscreen what is happening. Less visible when you are standing on the ground.

    Anyhow, I totally aggree with what you are saying in regards to beginners, especially the bit about not such steep banks!! Personally, Idon't teach to pull up to turn tighter, simply because at the early stage when this is even a problem, most students can not run the throttle and turn and everything at the same time, so the risk of stalling if they pull to hard is greater. For the same reasons they turn too steep, they also pull too hard. I gotta admit, Ihave never had the "split S" problem happen to me with a beginner though, but I can see it happening.



  19. #19
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    RE: do ailerons provide lift?

    Lets go back to the original question and here it is.

    I was looking at my partialy completed plane and noticed how much larger the wing looks when I hold the ailerons up to it. (they are not installed yet). I understand the function of the ailerons is to control or direct the air flow ( i guess), but does it provide lift when in the nuetral state?

    Please note the question was about when the ailerons were in the "Neutral State".

    I stand by my answers. And not to be nit picking, but I have been working for engineers as a lab tech for close to 30 years in the flow business and have learned long ago to pay attention to the question.
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    RE: do ailerons provide lift?


    ORIGINAL: rhall999

    Now, can IΒ*pick on GarryHarris?Β* (Sorry Gary[img][/img])

    Now if you build two wings, one with ailerons, and another without ailerons , but of equal wing chord, I don't see how having ailerons would create any more lift than the wing built with ailerons. So I'm still saying no.
    Your test will not really tell you to much.Β* Both wings being equal chord, they will fly so close to the same that you will not be able to discern the difference.Β* If anything, there will be a small increase in drag on the aileron equipped wing due to the gap, but that is about it.

    If you would really like to see the difference in the lift made by the ailerons, just build one wing.Β* Build it with the ailerons and go fly it.Β* Fly it a few times to get used to the way it flies, and then cut the ailerons off, and go fly it again.Β* That will tell you what difference the ailoerons make.
    Go for it!
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    RE: do ailerons provide lift?


    ORIGINAL: rhall999

    I don't really disagree with any of your argument, but you're leaving things out. When you increase the angle of attack of a plane that's banked, some of the increase keeps you from dropping and some of it makes you turn tighter because, as you say, the lift vector is not vertical. If you are banked 45 degrees, which isn't unusual for a model, about half the angle of attack increase contributes to the the turn. If you're banked 85 degrees, most of it does.
    Hi Top, well, I did mention it in there actually:

    This increases the total lift vector, which allows the vertical component to again equal the weight. Now, looking at that diagram again, you can see how in a set angle of bank, simply applying up elevator will cause the airplane to climb. There will be a small increase in the horizontal component too, but in a ''normal'' turn, not enough to even notice the increase in turn radius.

    BUT, look what happens if we steepen the bank further. Now, the total lift vector is still being split, but the steeper the bank, the more of the lift is given to the horizontal vector. This will cause a tighter turn. (Remember, the tail area will cause the airplane to ''yaw'' when that horizontal lift ''pushes'' us sideway, thus turning the airplane.) So, now we have a large portion of our lift going to the horizontal vector and less to the vertical vector, now the airplane really wants to drop, so we need to increase the total lift a lot more. So, to do this we need to pull back some more to increase the angle of attack enough to increase the total lift to increase the vertical component to keep us up in the sky. Whew, lots going on here isn't there.
    I fly full scale as well as models, and the result of using elevator in a turn is VERYΒ*easy to see in a full size when you can physically feel and see out the windscreen what is happening.Β* Less visible when you are standing on the ground.

    Anyhow, I totally aggree with what you are saying in regards to beginners, especially the bit about not such steep banks!!Β* Personally, IΒ*don't teach to pull up to turn tighter, simply because at the early stage when this is even a problem, most students can not run the throttle and turn and everything at the same time, so the risk of stalling if they pull to hard is greater.Β* For the same reasons they turn too steep, they also pull too hard.Β* I gotta admit, IΒ*have never had the ''split S'' problem happen to me with a beginner though, but I can see it happening.


    I don't think we really disagree about anything except maybe what counts as "small." Our models are so overpowered that a 45 degree bank to turn is pretty normal, even with fairly tame models, and there you've got elevator contributing equally to tightening the turn and keeping the plane up. I have flown full scale, too, though not recently.
    Al Gunn
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    RE: do ailerons provide lift?

    "Neutral State"!
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    RE: do ailerons provide lift?

    You'll notice that the down aileron will add lift like a flap

  24. #24
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    RE: do ailerons provide lift?

    Still learning, I'd like to hear more comments.
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    RE: do ailerons provide lift?

    Ailerons or no ailerons if you reduce the wing area by removing part of the wing panel then you have reduced the amount of available lifting area and increased the wing loading at the same time.

    Bob
    Fly It Like You Stole It!!!


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