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johnodonovan
3rd May 2008, 16:52
hi guys 1 quick question.. just did a ppl theory exam.. theres a question we couldnt figure out. which type of flap creates the biggest pitch change?? any body know the correct answer for sure??

airfoilmod
3rd May 2008, 17:49
The one that's the most effective at its job?

Joe Monsoon
3rd May 2008, 18:22
Me think its a double slotted Fowler flaps :confused:

roljoe
3rd May 2008, 18:52
For me,

this will be the type whitch in addition of increasing the camber line will also increase the wing surface...

PA38-Pilot
3rd May 2008, 18:59
I fail to see how that is an important question for a PPL... at least, I never thought about it when flying...

SNS3Guppy
3rd May 2008, 23:18
It's a bad question, because the answer depends entirely on the aircraft. Some flap systems cause pitch changes up with X amount of flap deflection, then pitch down with the next amount of flap deflection, etc. Others no change, others great change, and others it varies considerably with the CG. It's entirely airplane model-dependent, rather than one type of flap system vs. another.

airfoilmod
3rd May 2008, 23:32
Except in a Piper, when extension of flaps accomplishes nothing at all. Badly attached wing surface, actually.

johnodonovan
4th May 2008, 07:18
thanks for reply to thead guys.. but it is a valid jaa ppl question and i said fowler but even my instructors dont know... horrific..

411A
5th May 2008, 00:18
The proper answer is...split trailing edge, under normal circumstances.
Ala, DC3 and many twin Cessna aircraft.

Cardinal
5th May 2008, 04:12
Given the same surface area and deflection, a fowler would be my guess, though I'm treading upon unstable ground disagreeing with 411. With the rearward translation of the surface it seems that would give your surface more arm, thus a greater net change in center of pressure. Apples to oranges of course, but I found the pitch change with flap extension to be more objectionable in Cessna singles (fowler) than Cessna twins (split).

Standing by to be corrected.

jxk
5th May 2008, 07:51
I thought the reason for a change of pitch when deploying the flaps was because of the change of airflow over the horizontal stabiliser NOT the change of C of P etc..