Comments on: The Alpha Measurement

By: Dick Bicknell

Dick Bicknell — Sat, 26 Feb 2011 02:07:55 +0000

THE AOA PRICE( $4000) INSTALLED IS NOT REALISTIC. COST INSTALLED IS ABOUT 1/2……IT WILL TELL YOU FAR MORE THEN YOUR AIR SPEED .

By: George hoselton

George hoselton — Sun, 13 Feb 2011 08:49:59 +0000

My opinion. Pilots are either by the numbers or they feel the flight characteristcs
of the plane in flight. Someone not intouch with the flight and just flying by the numbers won’t feel the wing approaching stall at a higher speed than they expect due to flap position greater than normal. Going into a short field requires full flaps when bonanza’s need very little for 3000 foot runway or more.

By: George hoselton

George hoselton — Sun, 13 Feb 2011 08:37:36 +0000

Bonanza’s with flaps down have sudden and full stall break. Keep it over 100 and only use necessary flaps on landing until on final. Type specific safety book taught me this.

By: Charles Lloyd

Charles Lloyd — Mon, 10 Jan 2011 18:45:52 +0000

Elbie, the Alpha System AOA does not have flap compensation. However, when calibrated in the flaps up configuration for my Skylane the lower stall speeds for extended flap settings make the indication slightly conservative.

Yes, it would be nice to have flap compensation similar to the Citation but for that you will pay even more bucks. Some of the responders are resistant at the current installed cost.

The Alpha System AOA uses differential pitot pressures and can be just as good as the vane type AOA system for GA light aircraft. My experience is with the Alpha AOA and not the Right Angle System so both may be just fine for light GA aircraft.

By: Elbie

Elbie — Fri, 07 Jan 2011 19:36:55 +0000

Naturally, I am a little biased on this, but to have an precise AOA you need a vane in the airflow, and it must correct for flap position if precision flying is desired. A stall warner is great, but why not get automatic bias of flap position, those of you that flew the Citation (I was an ATP designated examiner (CE-500 & 550 on it for 7 years and chief instructor) know how accurate it was, our AOA is within 1/2 degree, not to many of us can fly light aircrft that smooth. Some airfoils can get by without flap bias, but not that many.
The AOA is the best instrument for safety ~~ even more so if properly trained. All of my competitors instruments will help prevent the Stall / Spin acidents, as I said I’m biased having produced the RiteAngle series of AOA’s for 15 years.

By: Peter

Peter — Tue, 04 Jan 2011 19:53:38 +0000

On a related note, why is the ball only ever found under the turn indicator? Given its importance in keeping a stall form becoming a spin, I’ve always thought that the ball should be at the top of the panel — ESPECIALLY in airplanes used mostly for VFR.

By: Dan Rogers

Dan Rogers — Tue, 04 Jan 2011 01:37:21 +0000

Don, I’ll agree that there is slight variability of critical AOA as a result of power setting and flap position, but trim tab setting, don’t think so. Basically Mr. White is correct, the elevator position is a great indicator of AOA. Granted, an AOA indicator removes virtually all AOA guesswork. However stick position is a great indicator of when things can go south. Have a look at Alan Cassidy’s “Better Aerobatics.” In it, Mr. Cassidy, an aeronautical engineer and well-respected international aerobatic competitor, writes “Because elevator position and angle of attack are very closely interdependent during forward flght, the aircraft also always stalls at the same elevator control position.” He goes on to write, “Of course the feel of the elevator varies in all these positions [referring to various flight attitudes], both because of aerodynamic forces and because of different trim settings, but the stick/yoke position will always be the same.” If I had my druthers, I’d like to see an AOA indicator and an inclinometer in all aircraft. What a great combo.

By: Don Arnold

Don Arnold — Mon, 03 Jan 2011 14:56:43 +0000

To reply to Jack White, the stick postiion vs. AOA curve is not fixed, it changes with the power setting and with the trim tab setting. Sorry, you need an AOA to know AOA.

By: Charles Lloyd

Charles Lloyd — Mon, 03 Jan 2011 14:32:01 +0000

The STOL capability is not the major reason for installing an Alpha AOA system. Here are questions to ask yourself:
• What is the stall speed difference between flaps up and full flap configuration? Some heavy singles have a 20 knot variation is stall speed depending on flap configuration and landing weight.
• Do you ever forget to set flaps for takeoff or landing?
• Do you ever bank more than 20 degrees?
• Do you want more consistent landings?

These are the reasons I installed an Alpha AOA system in my Cessna 182 after flying Citations with AOA installed during my time at Cessna and NetJets. The AOA system is there to prevent a killer steep turn to final accident and provide consistent landing touchdown points and roll outs.

No the FAA and Flight Safety don’t emphasize AOA but that is not reason to not adopt a safer method for flying our airplanes. AOA is a life saver.

By: Jim Lied

Jim Lied — Sat, 01 Jan 2011 23:39:10 +0000

AOA is a no brainer. If I had to choose Airspeed or AOA to make a landing, the AOA would be the winner every time! I have flown Citations in and out of every type of airport including Telluride, CO. The AOA takes all the variables of weight, density altitude, angle of bank, icing etc and blends them into one easy to use indicator that tells the truth without bias. Of all the safety devices out there, the AOA is the most under estimated in it’s value to prevent stall/spin accidents.

Jim Lied ATP CFI MEI