I read Tridge's post at https://groups.google.com/forum/#!topic/drones-discuss/zdaEfa_EfBY and basically I would also love a mode where I can plug in my stall speed, APM Plane would calculate a predicted stall speed depending on the bank angle (that's known math) and then add a generous fudge factor to allow for airspeed errors which are more of an issue at lower speeds (percentage wise).
Note that in my dreams, I'd actually like a mode that's like manual (I fly manual all the time), but with stall protection like some full size planes have with a stick shaker or a stick pusher that forces the nose down if you run low on airspeed, but I understand from your post it's not trivial.
This is because while I can fly my planes just fine, my glider has become stall/spin happy now that it's very loaded, and when I fly without the goggles, it's just very hard for me to have any idea how close I am to my stall speed.
This video shows how I almost destroyed it after a very bad double stall spin on my base to final turn:
I got super lucky to recover this.
Clearly, I banked too much for my airspeed (I'm used to banking this glider and it does fine, but not as much with the extra weight and wing loading now). On the video it's obvious I was way too slow, but from the ground, I just couldn't tell (I had the goggles off for landing).
Obviously, I could do a much wider pattern and bank less for safety, but if there were a way APM Plane could help me by refusing to bank more if the speed is too low and/or pitching the nose down for me, leaving power application and the rest of the controls to me (i.e. almost the manual mode), that would rule.
FBWA isn't my favourite since it restricts my controls a lot and I know how to fly without it.
FBWB is not desirable since I want to control when the motor comes on to avoid having the propeller on video more than necessary. Although I'm not sure how easy or possible it is to land in FBWB anyway.
I also don't like the fact that they are not truly how planes fly, if I put aileron, the plane should continue to bank until I stop that input.
So this brings us to TRAINING mode. It could restrict the roll to less than LIM_ROLL_CD if my airspeed is too low and my altitude is too low to safely lower the nose automatically, or it would lower the nose to keep airspeed to a safe value as the bank increases (maybe up to a LIM_ROLL_CD of 45 to 60 degrees, After that preventing stall gets harder on some airframes).
Another option would be to create a STALLWARNING mode that would work like manual, but would send "bank warning" and "airspeed/stall warning" audio alerts to the ground station and even sound out the airspeed every few seconds if it drops below a certain value. That would allow for warnings to the pilot for light of sight flying without making guesses that could cause the plane to nose down on landing and as controlled by the APM and crash or prevent a flare because it thought airspeed was too low, but wasn't.
Would that be possible?
Logged this here
I should add that FBWA and FBWB now include stall protection in APM Plane 3.2 but I still wish for a manual like mode with just stall protection.
Tridge has now added stall avoidance to training mode, which is manual-like if you tune is appropriately (for AC 3.4).