6. On flap extension, initially it will stay tail up until the airspeed is reduced. But addition of any TE high lift device will allow a greater AofA and thus higher nose attitude and more tail upon on the vane. However, LE high lift devices allow the nose to be lower for a given AoA, thus airspeed. Thus tail will be lower on extension.
Ummm. Permission to disagree?
Instantaneously upon extension of any TE high lift device, assuming no speed change at first, aircraft nose must go down to maintain the same flightpath (for example, to maintain level flight). Therefore tail down on alpha vane.
After TE device extended, speed probably reduces, so vane goes more tail up to maintain the same flight path.
LE device - has the same immediate effect on the alpha vane as TE devices.
On a more general P of F note:
- Addition of any TE device - increases wing CL, therefore allows lower speed for any flight path. However, because it changes wing shape, the addition of a typical TE high lift device will allow a
lesser critical AoA and a
lower nose attitude at that AoA. On the alpha vane at the stall, tail will be not so far down with TE devices extended, than if they were retracted.
- Addition of any LE high lift device - permits a
greater critical AoA and a
higher nose attitude at that AoA. Alpha vane tail will be a long way down at the stall!
Hope this is not completely useless,
O8