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Old 03-11-2004 | 02:01 PM
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From: kampenhout, BELGIUM
Default RE: flaps + elevator

ORIGINAL: dick Hanson

I love flap discussions - -some really good info always pops up.
I have a question tho--
Flaps BIG advantage is in keeping the fuselage and its associated bits , at a LOWER angle, relative to angle of decent.
This means that the horizontal tailplane is ALSO decending at a lower AOA.
So the big question:
Doesn't the use of flaps really increase the relative efficiency of the horizontal tailplanes during decent?
Why is this never mentioned?
I recall an obscure NASA study , which showed the increased stability of a high AOA "mush",
thru actually keeping the entire horizontal tailplane AOA, aligned with the true path of flight.
Therefor--- in a flapped decent- the tailplane is at a lower AOA- than it would be if the plane were NON flapped and simply pitched to a high flare.
Too obscure???
If no one answers -I will hang up.
natural reaction of a pilot will be to trim the horizontal stab, to regain the balance. i don't think that the change of aoa of the stab once the airplane is in trim will have any effect on the elevator behaviours (pilot inputs)

the only effect I know on elevator behaviours when flaps are down is the fact that the airflow is more turbulent on it and that this could result in loss of elevator control is some case and configuration, but it has nothing to see with the aoa