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Leading and trailing edge flaps and winglets
Spinrecovery
Topic Author
Spinrecovery created the topic: Leading and trailing edge flaps and winglets
Hi,
I am just trying to fully understand the concept of different types of flaps both leading and trailing edge. When Kruger flap is extended, it increases the camber of the wing which also increases lift but does it also increase the wing area and coefficient of life as well? As for the slat, not only it increases the camber but also delay the airflow separation at high angle of attack which decreases stalling speed. I understand that extending the trailing edge flaps changes the wing camber but why does the center of pressure move aft? What are some of the winglet types and which one reduces the vertices the most? Last question, do all jetliners have inboard aileron and what is the main purpose?
Cheers
bobtait replied the topic: Leading and trailing edge flaps and winglets
All flaps except split flaps increase the effective camber of the wing and therefore increase the maximum lift coefficient. Kruger flaps increase the radius of the leading edge and therefore the effective camber with a small increase in wing area.
The slat does not increase the camber of the wing, but it modifies the behaviour of the airflow by assisting it to "take the corner" as it passes over the leading edge of the aerofoil. The delay in separation allows the wing to achieve a higher angle of attack before the stall occurs so the stalling angle is increased and the maximum lift coefficient is also increased.
Conventional trailing edge flaps produce extra lift in the vicinity of the trailing edge. If more lift is being generated towards the trailing edge, the centre of pressure moves aft. That's a bit like adding extra weight to the rear of an aircraft with a resulting aft movement of the centre of gravity.
As for winglets, they all inhibit the formation of vortices and reduce induced drag. The resulting reduction in total drag increases the lift/drag ratio and therefore the maximum range possible - that's what makes them popular in long range airliners. Regarding the different types of winglets, all I can say is that if any one was significantly better than the others everybody would be using that design.
