When you do your stall AOA calibration, you are teaching the AOA what the full-blown stall looks like on the sensor. If you want it to start talking a few knots faster, you can do what I did - do about 3 or 4 stalls and note very carefully the exact airspeed you stall at under current conditions, and then you calibrate the AOA unit using that stall speed plus about 4 knots - you never fully enter an actual stall during that calibration. The result is that the AOA will start chirping in your ear at stall + about 10 knots, and is in full-blown panic screaming mode at the actual stall point.
Greg,
I don't know that I want to "fool" the AOA system by programming it differently and with a false "stall point" when what I'm looking for is a way of getting the data it already has presented so that it's more useful. While your way is "safe", it would run counter to the way every angle of attack system I've flown behind operates; which is, stall at 1.0.
So, trying to puzzle this out, here's a screenshot of the flight data to an approach I made yesterday into Eastland, Tx:
At the top of the graph is AOA vs IAS in knots, at the bottom is GPS altitude.
I fly the final turn at 75 KIAS and slow to 70 KIAS (plus wind) on final...it was pretty windy and bumpy yesterday, so there's some variance AND this is just a snapshot of the interval from ~150' on down.
It looks like to me, flying final at ~70-75 KIAS, that's about 20-30 degrees of AOA. On the visual AOA display, the green ring (green donut) would give you your "On Speed" cue...but what would be an On Speed cue aurally? How many beeps per second?
With the AOA settings I've already got, I'm understanding now why I never hear it till I'm deep in the flare-it won't start chirping at me until 50%, and by what the graph is telling me, that's not happening until 6 inches above the runway. Obviously, I need to lower that number if I want to know what the wing is doing farther back in the pattern, but to what, and what "chirp rate" gives me an On Speed cue? Programming for a HUD for "on speed" would be easier...just set it that the green donut lights up when flying at the correct ref.
Said another way...what percent AOA (per the graph) is the best "On Speed" AOA for my wing on approach? 25%? 30%?
Is there a formula for this? Does Van's have this data on their airfoils?
Also, maybe some of our fighter community guys can help here that have/had both tone and visual AOA indications...What did you guys use?
Sid, what kind of beep rate did the Rhino have on approach or in the final turn? In the T-38, we didn't have tone...just the indexer and a panel gauge.
There is some thread drift going on here, off of Dynon's announcement, so my apologies for that.
We can move this discussion to another thread, if appropriate, because I would love to hear some thoughts on how to make my AOA system more useful than what I have now...and FYI Dynon, I still would like a HUD-type of AOA display, not something buried in the PFD! Just askin'!!!
Rob