Quote:
Originally Posted by NZtyphoon
First is an abridged lecture given by Frederick Handley Page describing the operation of what are, in fact, called automatic slots - the slats are simply the moving airfoil sections.
and, from 1939:
Operative words "the slot could be made to open at a pre-determined angle of incidence....make the wing stable at a large angles of incidence and so ensuring that, although the aircraft would stall, it would not "drop a wing" and go into a spin."
Therefore, automatic slots are not fully effective at all AOAs at low speeds, let alone combat speeds - which, BTW, have not been mentioned - until the wing has reached a certain, pre-set angle of incidence. What was the pre-determined angle of incidence for the 109? And at what speeds did the slots open?
Effectiveness v basic airfoil:
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Most of the questions you are asking have been answered by the chart in the post above yours.
The chart you have provided showing effectiveness vs basic aerofoil is quite dated, and I am not sure it can be taken as effective.
NACA did a later, more comprehensive study of wing lift devices, including leading edge slats, I have a copy somewhere in my files, and there should be a link at the NACA site.