How do Ailerons work??

N

njdem82

New Member
Hi Hope everyone has had a good weekend so far.

I was trying to better understand how ailerons work but have had some trouble wrapping my head around it. My understanding is that when I turn to the left , the left aileron goes up and that creates less lift in the left wing than the right wing. This makes the left wing dip and the resulting "attitude" (probably wrong word to use) vectors the vertical lift horizontally toward the left wing, making the plane "lift" to the left. Is this an accurate (though ofcourse oversimplified) description?? Please let me know any flaws or major ommisions.

My questions is why does the upward deflection in the aileron decrease the amount of lift in that wing?? Also is it just a matter of changing the chord line??? or does it also have to with relative wind disruption such as in elevator and rudder controls?? One thought that I had was that the downward deflection of an aileron acts almost like a flap and increases the lift in that wing , is that an accurate relation???

Any suggestions to help me better understand this would be appreciated. If possible any intuitive explanations would be great in addition to the hard mathematics of the matter. As always , Thank You
 
njdem82 said:
Hi Hope everyone has had a good weekend so far.

I was trying to better understand how ailerons work but have had some trouble wrapping my head around it. My understanding is that when I turn to the left , the left aileron goes up and that creates less lift in the left wing than the right wing. This makes the left wing dip and the resulting "attitude" (probably wrong word to use) vectors the vertical lift horizontally toward the left wing, making the plane "lift" to the left. Is this an accurate (though ofcourse oversimplified) description?? Please let me know any flaws or major ommisions.
Click to expand...

You are correct, Some of the vertical lift changes into horizontal lift resulting into "lift" to the left, the nose will weather-vane into the wind resulting in a turn.


njdem82 said:
My questions is why does the upward deflection in the aileron decrease the amount of lift in that wing?? Also is it just a matter of changing the chord line??? or does it also have to with relative wind disruption such as in elevator and rudder controls?? One thought that I had was that the downward deflection of an aileron acts almost like a flap and increases the lift in that wing , is that an accurate relation???
Click to expand...

Both of your assumptions would be correct. Changing the chord line will change the AOA (Angle of Attack).

Flaps also change the chord line which therefore changes the AOA, the difference between that and the aileron is that both flaps on both sides go down together.

The Elevator and rudder, when moved is also changing the chord-line and results in lift in either direction. The rudder is also a "wing" that can produce lift left or right.
 
njdem82 said:
Hi Hope everyone has had a good weekend so far.

I was trying to better understand how ailerons work but have had some trouble wrapping my head around it. My understanding is that when I turn to the left , the left aileron goes up and that creates less lift in the left wing than the right wing. This makes the left wing dip and the resulting "attitude" (probably wrong word to use) vectors the vertical lift horizontally toward the left wing, making the plane "lift" to the left. Is this an accurate (though ofcourse oversimplified) description?? Please let me know any flaws or major ommisions.

My questions is why does the upward deflection in the aileron decrease the amount of lift in that wing?? Also is it just a matter of changing the chord line??? or does it also have to with relative wind disruption such as in elevator and rudder controls?? One thought that I had was that the downward deflection of an aileron acts almost like a flap and increases the lift in that wing , is that an accurate relation???

Any suggestions to help me better understand this would be appreciated. If possible any intuitive explanations would be great in addition to the hard mathematics of the matter. As always , Thank You
Click to expand...

Your first paragraph is essentially correct. The ailerons basically change the shape of that portion of the wing. As you know, the line for the leading edge to the trailing edge of the wing is called the chord line. The angle between the chord line and relative wind is the angle of attack. And the higher the angle of attack, the more lift (Generally speaking) is created. So the downward deflecting aileron creates a larger angle of attack (More lift), while the upward deflecting aileron creates a smaller angle of attack (Less lift). The difference in the amount of lift between the two wings causes the aircraft to roll.

You can also use Newtons 3rd Law to explain it, which is a lot more simple. Upward deflecting aileron moves into the airstream and is pushed down by the force of the deflecting airflow. Downward moving aileron is pushed upward by the force of the deflecting airflow.

I always find it helps to see a picture. I think the PHAK has a few pictures of this.

EDIT: Got beat to it.
 
Ahhhh I see so it is a matter of changing the AOA and therefore changing the amount of lift (as well as drag which is where adverse yaw comes in). This clears up alot. Its harder to understand AOA when it comes to rudder but if I think about the plane on its side then its easier to see it as a "sideways elevator". Props really kill me but I suppose thats another thing , same principle ofcourse , it had just always been hard for me to visualize. I'm also going to start a thread on P-Factor at some point , once I have more educated questions.

In any case , Thank You for your help my first CFI made this sound so complicated , I now suspect that he had no idea what he was talking about --he emphasized drag.
 
njdem82 said:
I'm also going to start a thread on P-Factor at some point , once I have more educated questions.
Click to expand...

I'd recommend using the search feature on the forums before doing that. I'm fairly confident every question anyone has on p-factor has been addressed here in the last 3-4 months.
 
njdem82 said:
Ahhhh I see so it is a matter of changing the AOA and therefore changing the amount of lift (as well as drag which is where adverse yaw comes in). This clears up alot. Its harder to understand AOA when it comes to rudder but if I think about the plane on its side then its easier to see it as a "sideways elevator". Props really kill me but I suppose thats another thing , same principle ofcourse , it had just always been hard for me to visualize. I'm also going to start a thread on P-Factor at some point , once I have more educated questions.

In any case , Thank You for your help my first CFI made this sound so complicated , I now suspect that he had no idea what he was talking about --he emphasized drag.
Click to expand...

He probably emphasized the drag portion to point out how adverse yaw is created. Just keep in mind, the higher the AoA, the more lift AND drag.
 
SY737 said:
Just keep in mind, the higher the AoA, the more lift AND drag.
Click to expand...

Be careful with this claim. For ailerons it is accurate, for the wing as a whole it's vague and might lead to inaccurate conclusions.

Whenever we consider the airplane as a whole, you're often better off assuming lift as a constant. It makes it simpler and the inaccuracies can be covered when discussing stability.
 
How do ailerons work?

Pretty well IMHO. And they're easier to build than a warping wing.
 
njdem82 said:
I'm also going to start a thread on P-Factor at some point , once I have more educated questions.
Click to expand...

I only make myself out to be an ass for the personal gain of myself and others one time and one time only! :D

Yes, please do a search!
 
splash said:
I only make myself out to be an ass for the personal gain of myself and others one time and one time only! :D

Yes, please do a search!
Click to expand...

I'm not sure I understand , am I missing something? Did I say something wrong? Very confused and maybe proving your point if I interpretted it correctly
 
njdem82 said:
I'm not sure I understand , am I missing something? Did I say something wrong? Very confused and maybe proving your point if I interpretted it correctly
Click to expand...

No... you didn't say anything wrong. I think splash was engaging in self-depricating humor.
 
Unless you want the technical jargon, don't over think it. You already know that the ailerons work opposite to each other - when one goes up, the other goes down.

Next time you are driving or riding as a passenger down the highway, put your hand out the window and keep it flat relative to the airstream. Now tilt your hand down and you will experience the wind pressure from below pushing your hand back to the neutral. Now tilt it up and you will feel the opposite.

The exact thing is happening with your ailerons. You turn the control column left and the left aileron goes up which produces downward pressure from lifting the aileron into the airstream flowing over the upper part of the wing. Simultaneously, the right aileron is pushed down into the airstream which applies upward pressure on the right wing.

With downward pressure on the left wing and upward pressure on the right wing, the airplane will enter a left bank just as you asked it to.

The technical stuff can come from the smart guys here.
 
calcapt said:
Unless you want the technical jargon, don't over think it. You already know that the ailerons work opposite to each other - when one goes up, the other goes down.

Next time you are driving or riding as a passenger down the highway, put your hand out the window and keep it flat relative to the airstream. Now tilt your hand down and you will experience the wind pressure from below pushing your hand back to the neutral. Now tilt it up and you will feel the opposite.

The exact thing is happening with your ailerons. You turn the control column left and the left aileron goes up which produces downward pressure from lifting the aileron into the airstream flowing over the upper part of the wing. Simultaneously, the right aileron is pushed down into the airstream which applies upward pressure on the right wing.

With downward pressure on the left wing and upward pressure on the right wing, the airplane will enter a left bank just as you asked it to.

The technical stuff can come from the smart guys here.
Click to expand...

Hey Thanks. Also you are right about the overthinking aspect. One of the downfalls of going to a 141 school where we dress up like airline captains is that we tend to beat everything into the ground to justify the high cost and academic nature of the course.

More and more I feel that flyinhg is a trade and mostly intuitive. Ofcourse we should always be learning , if one flies into known adverse conditions out of ignorance it goes to show a lack in ground training , but I'm not sure that being asked how many degrees the nose wheel of a particular plane is helpful as far as safety of flight is concerned. Shows that you are putting in effort I suppose.

One thing is that the premise which states "that anyone can do this" means that failure to land properly is either the CFI's fault or yours for not putting in the effort but the truth is that some are more naturally inclined (I also noticed that some of the younger guys caught on more quickly at first) and I think that some people simply will not make good pilots just as some would not make good bakers or electricians. Otherwise dedicated practice makes one proficient not to mention getting over mental blocks. For instance People telling me that instrument flying is the toughest thing in the world did me a huge dis-service , its no tougher than anything else and now I find it much easier than VFR since it is so regulated and organized almost feels like the plane lands itself.

Anyway Im going to force myself to stop babbling , once again thanks for the help with a fairly useless question. I am sure that I will have another within the week :)
 
mshunter said:
Ailerons wrok by................................MAGIC!
Click to expand...

No... one goes up while the other one goes down. Sometimes using cables, sometimes push/pull tubes, sometimes hydraulics, sometimes by a squirrel who is fed a nut every time you move the yoke.
 
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