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777 aileron..?

tathepilot

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On a flight from cdg to ewr I noticed what I believe is an 'inboard aileron' on the 777.

This 'inboard aileron' works a lot at lower speeds, to keep it clear, it is located inboard between the inner and out flaps on the wing.

can anyone shed some light on this, as to the workings of this 'inboard aileron'
 

Tarzan

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The inboard functions at high speeds while the outboards are locked to prevent the wing fom twisting.
 

Flying Illini

Hit me Peter!
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PM typhoonpilot...he flies a 777 and would be able to shed some light on the IB aileron.
 

typhoonpilot

Daddy
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Flaperon

This 'inboard aileron' works a lot at lower speeds, to keep it clear, it is located inboard between the inner and out flaps on the wing.

What you are referring to is probably the flaperon. The flaperons are located between the inboard and outboard flaps on both wings. They are called flaperons because they move like ailerons in response to control wheel movement but they also move down and aft in proportion to trailing edge flap extension. During high speed flight the ailerons and spoilers 5 and 10 are locked out, leaving the flaperons and remaining spoilers to provide roll control. The flaperons do seem to move a lot when viewed from the cabin.

TP
 

mattpilot

Finally! Graphical TFRs!!
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@typhoon


does it have anything to do with the momentum the ailerons/flaperons make?

For example, the outboard ailerons have a greater distance from the CG, thus provide greater rolling force with a smaller deflection. On the otherhand, you have the inboard flaperon that is a smaller distance from the CG, thus needing a greater amount of deflection to produce the same rolling moment as the outboard ailerons... And they do that to equalize the rolling moment produced along the wing.


This is just a guess ..... am i way off or somewhat close?
 

typhoonpilot

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Hi Matt:


You are pretty close. Obviously the outboard aileron would have a much higher turning moment for a given deflection. At the high speeds of a commercial airliner this has some pretty serious negative consequences one of which is known as aileron reversal.

This is taken from Pprune:

"Aileron reversal is a very serious potential problem for most aircraft with swept wings which operate at high subsonic mach number and beyond. Due to the flexible nature of the wings, the elastic deformation at high speeds due to aileron deflection can be sufficient to cause reversal. The obvious way to solve it is increase bending stiffness but this has weight penalties, so as always there is a trade off. This has to be a significant reason to use inboard/outboard aileron configurations."


TP
 
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