"Ed Rasimus" wrote in message
news
On Sun, 11 Jan 2004 06:05:28 -0600, "John Carrier"
wrote:

If they extend when airpressure is reduced as airspeed slows, then it
would be redundant to add "also when a certain AOA is achieved"
because that is the inevitable, inexorable, undeniable result of
slowing.

Just musing here Ed; :-))))))

I might be missing something in what you're saying about slat extension Ed,
but FWIW, although it's true that dynamic pressure will bring out an
aerodynamic LE slat as airspeed is reduced and angle of attack is increased
as the result of that slowing, the only common denominator that SHOULD be
used for an aerodynamic slat extension parameter is aoa, not airspeed! You
can pull 12 units in an A4 and get a slat extension at ANY airspeed!! Using
airspeed as the single parameter seems to me to be like using airspeed as a
stall parameter instead of aoa. (Airspeed works for stall at a specific GW
for a 1g stall, but goes to hell when you start pulling g!! The alpha units
or degrees aoa for CLmax producing that stall however, remain the same. The
same thing goes for an aerodynamic slat extension. You can extend slats in
an A4 by reducing the airspeed all right, but ONLY when you reach 12 units
aoa which works for an airspeed explanation at 1g level flight decel.
BUT!!!! You can ALSO extend the same slats at much higher airspeeds by
accelerating the airplane to 12 units. The airspeed for each extension
scenario will be quite different, but the same 12 units still apply! AOA is
the right parameter for aerodynamic slat extension, and what's used in the
test community. I have to admit though, I can't for the life of me remember
however how the Natops for the A4 presented this information :-)))

Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
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