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Angle of Attack (AOA) System


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Afternoon All: I am taking abreak from helping Nancy look after ort 20 month old grandson Henry. I was reading an AOPA Magazine article to Henry, who while not enthralled, sit down with Luci, the Attack Basset, and listen to some information about AOA.


It seems that FAA Small Plane Directorate has ruled that (Alpha Systems) AOA indicators may be added with normal log book entries as a minor alteration. Sorry. but when FAA says minor I am suspect, particularly if it is a system, whih the AOA certainly is. Back in the last century when one of my life preoccupations was the RF-4C, we had an AOA system that we used all the time. Out AOA was a visual and aural system that had an oval lin the center and thes was on speed aand you could maneuver the aircraft or land at the optimum speed/ AOA. For example, in the F4, any weight of airspeed had a correct on speed, so from the back seat one could fly a very good final approach without seeing the r/wy. I loved the AOA.


In the CT, I think we have had this discussion before, but I am again curious. The Dynon AOA will tell you when you stall as the green and yellow lites meld into the red, then disappear. However, I have found thatthe display is inconsistent, but that it does indicate a stall at the same airspeed. What I am saying is the the yellow lines and red lined do not look the same each time the plane stalls. However, I have found that on a climb out lreaving two yellow lines seems to be pretty close to 76 kts. On landing I have tried to correlate display with the IAS; I found that on successive approaches the display is not the same for the same airspeed (I know pilot inconsistency); I would hesitate to try to use it down to the runway because of the discrepency. Nonetheless, in times past it AOA was was an intregal flight instrumentation that was used extensively. I should also mention that the Dynon display, while easy to read, is also in an awkward location, requiring eyes inside the cockpit too much for my taste.


Anyway I am curious if anyone has some thoughts about AOA. Oh yes, my article Old Folks Fly was publiched in Litght Plane World in this month's edition.


See ya, Ken and Nancy Nolde N840KN, haven't turned a wheel in two weeks due to weather and windsm sux!

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  • 4 weeks later...

Hi Ken. You should be an expert on AOA indicators - I seem to recall reading that the AOA is (was?) one of your main instruments during your Military flying?

Dick: Yes the AOA was a primary in the F-4. However, I was looking at it in the context of LSA (CTLS) flying. I was simply wondering if anyone had experience with it in the LSA application? As I noted im original item, the DYNON AOA is illy located for easy use and while I can see the green, yellow, and red lines disappear as the AOA increases, the question I posed to readers (and also to Dynon) was what should the display look like when you are "on speed?" The F-4 had a nice donut to fly along with a steady tone. So, while I do know about AOAs, I was hoping for a bit more info, if available.


Ken Nolde, 840KN

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I agree the AOA is in an awkward spot. It would be better as a HUD or something closer to the out-the-window view.


I used an AOA in a Citation, mostly for approaches and climb outs. It became a favorite instrument.


For some reason, in flying the CT I didn't use the AOA much. Recently, I flew some stalls reference it and it seemed to be consistent. It stalled at the top of the red. I've been meaning to integrate it into my approaches for the same reason you cite - it is so reliable (assuming it works right). I'll be checking it out more. And wishing it were in a better location.



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