In a message dated 12/13/03 11:57:10 PM Pacific Standard Time,
europa-list-digest@matronics.com writes:
Stall warners do not degrade the aerodynamics
and can easily be set to give a warning at any desired speed/AOA.
Stall warning devices such as the leading edge vane can only give warning
at one fixed flap setting correctly. This is why they are so much of a
nuisance. They must be set to go off when the stagnation point of the airflow
changes and moves the vane upward, closing a micro switch which make the light
or
horn go off. This must be at the lowest AOA which a stall can occur, otherwise
it would not give stall protection with the wing in that configuration.
For a stall warning to be accurate and reliable it must have some sort of
method of correcting for flap position.
To certify an aircraft in the US, the stall warning must go off a minimum of
5 kts above the stall. This is in the flaps up configuration, which is why
the stall warners are so inaccurate on all light production aircraft with the
flaps down, especially aircraft with very effective flaps.
You can set your stall warning for flaps extended on your experimental
aircraft, but then you wouldn't have adequate stall warning protection with the
flaps up.
Elbie
Old CFI
EM aviation
www.riteangle.com
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