Aerodynamics Discuss the physics of flight revolving around the aerodynamics and design of aircraft.

do ailerons provide lift?

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Old 01-14-2013, 10:52 AM
  #126
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Default RE: do ailerons provide lift?

BTW, guys, welcome to the Aeronautics forum.

Keep in mind that the question has already been thoroughly answered.

And it should be mentioned that every time this issue has come up in here, since everyone with any understanding of aeronautics already knew the answer, the topic didn't last very long. Only people who stayed around weren't in that group but enjoyed arguing stuff.
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Old 01-14-2013, 11:06 AM
  #127
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Default RE: do ailerons provide lift?

Quote:
ORIGINAL: ovationdave

......The ''the wing does what it needs to'' comment was kind of what I was thinking, but the more I thought about it, it makes sense since any object finds its natural path while air is passing around it.

~Dave
Dave,

Please, note that DaRock's statement reads: "....the wing assumes the AOA needed to provide the lift you demand with your pilot input trim or elevator position."

That means that if we allow the airfoil to "find its natural path", it will provide zero lift.
The pilot must force the airfoil to face the airstream in a non-natural way via the elevator (using trim or manual input).

The higher the AOA, the stronger the lift (up to certain max value), the less natural the path.
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Old 01-14-2013, 11:21 AM
  #128
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Default RE: do ailerons provide lift?

Quote:
ORIGINAL: da Rock


Quote:
ORIGINAL: sensei
IMO ailerons will provide lift only if they are part of the airfoil of the wing, the chord would be then from the leading edge of the wing to the trailing edge of the aileron.
If the ailerons are flat with no airfoil profile (as on some sports planes and fun fly's), the chord would then be from the leading edge of the wing to the hinge line as the aileron being parallel top and bottom would provide no lift.

Can't think of many airplanes where the ailerons aren't part of the wing's airfoil, but a couple come to mind. The Stuka and the JU52 both fit the description.

The ailerons on those birds contribute lift and drag.

And to the point of this discussion, their area is included in the area of the wing by most AEs when talking about the simpler aspects of the airplanes. Can you think of any outside part of any airplane doesn't contribute to drag and can't provide lift?
I couldn't agree more with you and this was not my statement, I just copied it from Drac1 to make my point.

Bob
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Old 01-14-2013, 11:44 AM
  #129
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Default RE: do ailerons provide lift?

To put a fine point on it

ALL the horizontal area of a craft can provide lift
a perfectly round fuselage can provide lift - and many do
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Old 01-14-2013, 11:53 AM
  #130
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Default RE: do ailerons provide lift?

Quote:
ORIGINAL: Lnewqban

Please, note that DaRock's statement reads: ''....the wing assumes the AOA needed to provide the lift you demand with your pilot input trim or elevator position.''

That means that if we allow the airfoil to ''find its natural path'', it will provide zero lift.
The pilot must force the airfoil to face the airstream in a non-natural way via the elevator (using trim or manual input).

The higher the AOA, the stronger the lift (up to certain max value), the less natural the path.
No argument there.......
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Old 01-14-2013, 01:31 PM
  #131
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Default RE: do ailerons provide lift?

As a side note many years ago we found that the nacelles on turbofans also provided a lot of lift. My boss and I tested a 747 with 10% of the lift provided by the engines. We had to strengthen the nacelle struts after we twisted them in early testing.
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Old 01-14-2013, 05:33 PM
  #132
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Default RE: do ailerons provide lift?

Here is my thought. Do ailerons contribute to lift in neutral...............no, not really (very insignificant). Take both ailerons off and the plane would still fly virtually the same (lift wise), with just slightly more drag. Not much fun to control, but with ample lift. The lift of the wing is generated in front of the ailerons. Actually, a stunt pilot by the name of Kent Pietsch, flying an Interstate Cadet called Jelly Belly, sheds an aileron in flight with no issues. Many pilots returned to their bases during WWII with ailerons shot off.

Lift from the aileron is increased only when the aileron is lowered, and reduced only when the aileron is lifted. Increasing lift (the lower aileron) also increases drag, so the high wing has more drag than the low wing, thus the adverse (opposite) yaw. This is why we reduce the down travel as compared to the up travel to balance out this effect, and lesson the need for rudder in those turns, which also adds even more drag.

Hope I didn't make this more confusing.

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Old 01-14-2013, 05:57 PM
  #133
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Default RE: do ailerons provide lift?

And look what happens with one question HUH
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Old 01-14-2013, 06:06 PM
  #134
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Default RE: do ailerons provide lift?

Quote:
ORIGINAL: ram3500-RCU

Here is my thought. Do ailerons contribute to lift in neutral...............no, not really (very insignificant). Take both ailerons off and the plane would still fly virtually the same (lift wise), with just slightly more drag. Not much fun to control, but with ample lift. The lift of the wing is generated in front of the ailerons. Actually, a stunt pilot by the name of Kent Pietsch, flying an Interstate Cadet called Jelly Belly, sheds an aileron in flight with no issues. Many pilots returned to their bases during WWII with ailerons shot off.

Lift from the aileron is increased only when the aileron is lowered, and reduced only when the aileron is lifted. Increasing lift (the lower aileron) also increases drag, so the high wing has more drag than the low wing, thus the adverse (opposite) yaw. This is why we reduce the down travel as compared to the up travel to balance out this effect, and lesson the need for rudder in those turns, which also adds even more drag.

Hope I didn't make this more confusing.

I have also seen him fly his cadet shedding his aileron at many air shows with no issues, but as you stated he is a stunt pilot that has logged many hours doing this as part of his air show and has trained himself to fly the airplane under these conditions.

Bob

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Old 01-16-2013, 12:59 PM
  #135
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Default RE: do ailerons provide lift?

Quote:
ORIGINAL: CGRetired

This thread has gone way beyond the level that would keep it in a ''Beginners'' forum. .....so I moved it here, to the Aerodynamics Forum, instead.

CGr
Beginners Forum Moderator
This explains why a 6 page thread miraculously appeared here....


Quote:
ORIGINAL: GaryHarris

I still stand by my take that in a neutral position, flat ailerons do not add any more lift compared to a wing of equal chord.....
Gary, and you others that are saying much the same thing, you are both right and wrong at the same time.

Right or wrong the aileron is part of the airfoil shape. You can't consider the one without the other or consider them in isolation from each other. Trying to do so is rather meaningless. So the question becomes how does the aileron affect the airfoil as the shape changes from a tapered one to a flat one?

What happens with a flat stock aileron stuck onto the back of a flat bottom/curved top airfoil is that it adds a degree of trailing edge reflex to the camber line. This is the case if the aileron is in line with the bottom flat surface. Adding some reflex to the camber line will slightly reduce the maximum achievable lift coefficient of the airfoil. That means that for a given angle of attack the lift will be slightly less than if the aileron was of the proper airfoil shape and tapered in a way that the camber line was a constant arc like shape without the "S" reflex caused by the added on flat aileron style.

That make sense?

Now does having the flat aileron affect the overall airfoil such that it only lifts as much as the airfoil would if the aileron was removed? That could only be determined by comparing the wing with and without the aileron in place. But generally wing area trumps relatively minor camber line variations. So even with the flat aileron in line with the lower surface the airfoil will PROBABLY produce more lift with the aileron in place than it would if the aileron was not there.



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Old 01-17-2013, 07:15 AM
  #136
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Default RE: do ailerons provide lift?

As long as the old stories about curved surfaces and difference in speed over the top surface etc., continue
Some will continue to think that it is th e shape which provides lift
Not simply the area and how it is projected.
Lift is NOTHING but difference in pressure on a solid body
doesn't matter what the shape may be - If you have enough pressure difference (no matter how you got it- size/shape) movement ) you can provide lift.
Don't believe it ?
Too bad
Efficient lift - is a totally different question -and some students of this will keep you busy or bored with picking all this
into examples and math examples and charts and quotes from long gone discoveres and scientists - on n on
It's all just pressure differential at work.
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Old 01-17-2013, 08:42 AM
  #137
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Default RE: do ailerons provide lift?

And bottom line, stated numerous times, is YES they do.
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Old 01-17-2013, 04:27 PM
  #138
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Default RE: do ailerons provide lift?

Guess the physics at the heart of the answer to this question, I will leave to those who understand it. I am not an aeronautical engineer, but I have flow both full scale and RC.

This I do know. I have had at least two occasions in the last 45 years in this hobby when my plane developed flutter bad enough to shed parts. Once it was only one aileron, and once two out of four left the aircraft(there have been a couple other times, but nothing separated). Both times I flew the aircraft to a successful landing (because I can fly the rudder) and had no issues with wing loading or lift in the process. It seems that the lifting effect of any aileron in neutral is small. I would be willing to take just about any prop driven RC aircraft airborne without it's ailerons, and I'm confident it would fly just fine. I do prefer them though, in all honesty.
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Old 01-17-2013, 05:24 PM
  #139
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Default RE: do ailerons provide lift?


Quote:
ORIGINAL: ram3500-RCU

Guess the physics at the heart of the answer to this question, I will leave to those who understand it. I am not an aeronautical engineer, but I have flow both full scale and RC.

This I do know. I have had at least two occasions in the last 45 years in this hobby when my plane developed flutter bad enough to shed parts. Once it was only one aileron, and once two out of four left the aircraft(there have been a couple other times, but nothing separated). Both times I flew the aircraft to a successful landing (because I can fly the rudder) and had no issues with wing loading or lift in the process. It seems that the lifting effect of any aileron in neutral is small. I would be willing to take just about any prop driven RC aircraft airborne without it's ailerons, and I'm confident it would fly just fine. I do prefer them though, in all honesty.

Know what causes flutter?

You've just provided an observation that proves that ailerons provide lift.
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Old 01-17-2013, 06:13 PM
  #140
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Default RE: do ailerons provide lift?

The lack of mass dynamic balancing, the lack of torsional rigidity within the structure or control surface. How is that for starters?

Bob
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Old 01-17-2013, 06:46 PM
  #141
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Default RE: do ailerons provide lift?

Quote:
ORIGINAL: ram3500-RCU

Guess the physics at the heart of the answer to this question, I will leave to those who understand it. I am not an aeronautical engineer, but I have flow both full scale and RC.

This I do know. I have had at least two occasions in the last 45 years in this hobby when my plane developed flutter bad enough to shed parts. Once it was only one aileron, and once two out of four left the aircraft(there have been a couple other times, but nothing separated). Both times I flew the aircraft to a successful landing (because I can fly the rudder) and had no issues with wing loading or lift in the process. It seems that the lifting effect of any aileron in neutral is small. I would be willing to take just about any prop driven RC aircraft airborne without it's ailerons, and I'm confident it would fly just fine. I do prefer them though, in all honesty.
It's good to know that you were flying something with dihedral when you shed your ailerons, the outcome would most likely have been different, at least when you lost all your ailerons. Yaw impute doesn't help to pick up a dumped wing with the absence of dihedral.

Bob
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Old 01-17-2013, 07:36 PM
  #142
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Default RE: do ailerons provide lift?

Quote:
ORIGINAL: sensei

Quote:
ORIGINAL: ram3500-RCU

Guess the physics at the heart of the answer to this question, I will leave to those who understand it. I am not an aeronautical engineer, but I have flow both full scale and RC.

This I do know. I have had at least two occasions in the last 45 years in this hobby when my plane developed flutter bad enough to shed parts. Once it was only one aileron, and once two out of four left the aircraft(there have been a couple other times, but nothing separated). Both times I flew the aircraft to a successful landing (because I can fly the rudder) and had no issues with wing loading or lift in the process. It seems that the lifting effect of any aileron in neutral is small. I would be willing to take just about any prop driven RC aircraft airborne without it's ailerons, and I'm confident it would fly just fine. I do prefer them though, in all honesty.
It's good to know that you were flying something with dihedral when you shed your ailerons, the outcome would most likely have been different, at least when you lost all your ailerons. Yaw impute doesn't help to pick up a dumped wing with the absence of dihedral.

Bob
Well, sorry to disappoint. Both were with biplanes, and high performance ones at that. They were years apart. The first was with an old Cermark Pitts. Lost one of the top wing ailerons. The second was with a 33% Weeks Solution. This one was much worse. The wings looked like hummingbird wings. I'm sure it was a second or two from disintegrating by the time she had settled down and stopped shuttering. By then, both ailerons on the right side were gone. As I said, I was able to fly both planes and land normally. In both cases, all the aileron servos had been stripped. All I had was rudder and elevator.
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Old 01-18-2013, 04:30 AM
  #143
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Default RE: do ailerons provide lift?

Quote:
ORIGINAL: ram3500-RCU

Quote:
ORIGINAL: sensei

Quote:
ORIGINAL: ram3500-RCU

Guess the physics at the heart of the answer to this question, I will leave to those who understand it. I am not an aeronautical engineer, but I have flow both full scale and RC.

This I do know. I have had at least two occasions in the last 45 years in this hobby when my plane developed flutter bad enough to shed parts. Once it was only one aileron, and once two out of four left the aircraft(there have been a couple other times, but nothing separated). Both times I flew the aircraft to a successful landing (because I can fly the rudder) and had no issues with wing loading or lift in the process. It seems that the lifting effect of any aileron in neutral is small. I would be willing to take just about any prop driven RC aircraft airborne without it's ailerons, and I'm confident it would fly just fine. I do prefer them though, in all honesty.
It's good to know that you were flying something with dihedral when you shed your ailerons, the outcome would most likely have been different, at least when you lost all your ailerons. Yaw impute doesn't help to pick up a dumped wing with the absence of dihedral.

Bob
Well, sorry to disappoint. Both were with biplanes, and high performance ones at that. They were years apart. The first was with an old Cermark Pitts. Lost one of the top wing ailerons. The second was with a 33% Weeks Solution. This one was much worse. The wings looked like hummingbird wings. I'm sure it was a second or two from disintegrating by the time she had settled down and stopped shuttering. By then, both ailerons on the right side were gone. As I said, I was able to fly both planes and land normally. In both cases, all the aileron servos had been stripped. All I had was rudder and elevator.
Don't get me wrong, I am happy that your encounters were both victories, but even in the case of both your Pitts and your Weeks one or both wings are swept back so in essence acting like dihedral from a rudder impute standpoint. Back in the mid 90s I sponsored 5 Rice University mechanical engineering students in a heavy weight R/C aircraft lift competition held in DeLand Florida. My part of the sponsorship was to supply the students with composite materials, the technology of use and assembly of those materials only, and I was also the pilot, what I could not do was assist in the overall design of the aircraft. Their first aircraft wing design did not have ailerons, sweep, or dihedral, it was an engine, rudder and elevator design only and I knew what was going to happen, but their professor was adamant of my silence. So the test flight went like this, the aircraft rotated, climbed out gaining altitude until the wing slowly began to drop to one side, as I fed in counter rudder it had no effect at all on lifting that wing, we could see the airplane yaw, but it was not lifting the low wing, so I pulled back on throttle and elevator just a little to bring it back around, the bank angle was still very shallow and it came back around. This went on for about two full circles around the field, but the bank angle was slowly increasing the longer it flew and finally when that angle reached a certain point she started downwards, so I killed the engine and we all watched it go in because there was nothing I could do to lift that wing once it started over. This all happened in really slow motion, I mean it was like 5 minutes from takeoff to impact while I was throwing everything I had rudder wise at it. I am happy to say that the second design was very successful and we had a great time in Florida.

Bob

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Old 01-18-2013, 04:31 AM
  #144
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Default RE: do ailerons provide lift?

*
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Old 01-18-2013, 06:42 AM
  #145
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Default RE: do ailerons provide lift?


Quote:
ORIGINAL: sensei

The lack of mass dynamic balancing, the lack of torsional rigidity within the structure or control surface. How is that for starters?

Bob
Without a force on them, leave off whatever you want and it ain't gonna happen.

Sorry, but those aren't the starters. The pressure differential is the starter. The existance of those simply proves they are needed to counter a force.
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Old 01-18-2013, 06:52 AM
  #146
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Default RE: do ailerons provide lift?

BTW, the consequences of the loss of a small percentage of wing area might prove something but only if the percentage lost could be proven to be significant. When the consequences are negligible, the conclusion is just as valid that the area was insignificant.
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Old 01-18-2013, 07:15 AM
  #147
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Default RE: do ailerons provide lift?


Quote:
ORIGINAL: da Rock


Quote:
ORIGINAL: sensei

The lack of mass dynamic balancing, the lack of torsional rigidity within the structure or control surface. How is that for starters?

Bob
Without a force on them, leave off whatever you want and it ain't gonna happen.

Sorry, but those aren't the starters. The pressure differential is the starter. The existance of those simply proves they are needed to counter a force.
I sure can't disagree with that, your are right, without force, no need for mass balancing or anything for that matter...

Bob
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Old 01-18-2013, 04:32 PM
  #148
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Default RE: do ailerons provide lift?

Interesting discussion, and many good points made. I learn a lot from post by guys who understand aerodynamics, aircraft design, and physics better than I do.

But I have a ton of work to do for customers, so back to building for me. At ease, and carry on.
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Old 01-25-2013, 11:03 AM
  #149
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Default RE: do ailerons provide lift?

If you took a wing without ailerons, and cut a portion of the trailing edge to make an aileron, the wing would generate the same amount of lift.
If you have a symmetrical airfoil, and deflect the aileron, the effective airfoil will be challenged. This change will also change the lift.
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Old 01-25-2013, 11:25 AM
  #150
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Quote:
ORIGINAL: ram3500-RCU

This I do know. I have had at least two occasions in the last 45 years in this hobby when my plane developed flutter bad enough to shed parts. Once it was only one aileron, and once two out of four left the aircraft(there have been a couple other times, but nothing separated). Both times I flew the aircraft to a successful landing (because I can fly the rudder) and had no issues with wing loading or lift in the process. It seems that the lifting effect of any aileron in neutral is small. I would be willing to take just about any prop driven RC aircraft airborne without it's ailerons, and I'm confident it would fly just fine. I do prefer them though, in all honesty.
Well, yeah, a model that had its ailerons off the wing for whatever reason would still fly well enough. The ailerons add maybe 5-10% to the average wing area. So without them it's the same as increasing wing loading 5-10%, which means the remianing wing has to generate 5-10% more lift for S&L.

Many models don't have a problem in such a situation since they are very lightly loaded to begin with.

But in something that has a much higher wing loading than the typical weekend model, say, something built specifically to lift as high a load for a given power possible (for some college competition for example), I'll tell you with certainty that wing normally occupied by ailerons better be there or else the load carrying capacity will suffer.
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