I am thinking of adding an AOA to my plane.  The two models that I am looking at are the Bendix King KLR 10 (http://www.bendixking.com/Products/Flight-Controls-Indicators/Indicators/KLR-10) and one of the Alpha Systems units (http://www.alphasystemsaoa.com/)

My question has to do with the calibration.  Both systems require a calibration at 3 points:

1.      On Ground

2.      Optimum Alpha Angle

3.      Cruise

 

The “on ground” and “cruise” are self explanatory, however the definition of “Optimum Alpha Angle” seems a little “loosey-goosey” to me.  Here are the definitions:

 

Alpha Systems “Optimum Alpha Angle”

·         Able to hold altitude – as close to 0 VSI as possible, zero sink

·         Full aileron, elevator and rudder control – no buffet or loss of control surface stability

 

Bendix King “Optimum Alpha Angle”

·         Able to hold altitude, 0 Vertical Speed, zero sink (5 to 10 fpm climb OK)

·         Full aileron, elevator and rudder control, not in a buffet, pilot to identify the set point by

pitching back slowly to a pitch no longer able to climb but able to hold altitude with full

control of the airplane.

 

First of all, since this is a system meant to be used in landing (or at least that is how I will mostly use it), I intend to calibrate the “Optimum Alpha Angle” in landing configuration (gear down, full flaps).  However, determining when I have “full aileron, elevator and rudder control” isn’t all that clear to me.  I am sure that I can tell when I have aileron, elevator and rudder control – but the “full” part is less clear.  Does that mean a full control deflection?  Not something I am anxious to try that close to stall.

 

Alternatively, I could just do a stall in landing configuration and set the “Optimum Alpha Angle” to 1.3 x stall.

 

Advice?

 

D. Brunner

N241DB 750 hours