Request for DMMS speed indication or audible warning.

[BMW_X6M]

DMMS is explained as Defined Minimum Maneuvering Speed. The speed below which you should not be banking to avoid a stall while airspeed is low. It is an additional safety factor to remember to avoid excessive banking when the airspeed is low. In my RV-9A aircraft it is about 70 knots. The calculation is 1.404 x VS1.
(Refer to Dan Gryder and AQP)

I do try to maintain this safety margin. It would be nice to have a setting in the Dynon software to add a marker in the airspeed display. It could also be beneficial to allow for an audible alarm if desired when slowing below this airspeed.

The Angle of Attack system works very well and has been very helpful with avoiding a stall from my experience. My thought is that AOA gives a warning at a very slow airspeed and it might be nice to have a previous warning prior to getting that slow.

 

[Rhino]

Maneuvering speed can be set in AIRSPEED LIMITATIONS if you want to use it for that. The problem with an alarm is you'll be getting the alarm every time you go below 70 knots. Who would want that?

 

[n28et]

BMW, you wrote, “The Angle of Attack system works very well and has been very helpful with avoiding a stall from my experience. My thought is that AOA gives a warning at a very slow airspeed and it might be nice to have a previous warning prior to getting that slow.”

Actually, AOA gives a warning as you approach the “critical AOA” (the point at which the wing will stall) regardless of airspeed. Remember you can stall an airplane at any airspeed. If you refernece AOA during maneuvers there is no need to worry about airspeed as AOA is unaffected by bank angle (load factor), or weight. Airspeed is a proxy for angle of attack and always lags. Better to focus on AOA than airspeed IMHO.

 

[BMW_X6M]

BMW, you wrote, “The Angle of Attack system works very well and has been very helpful with avoiding a stall from my experience. My thought is that AOA gives a warning at a very slow airspeed and it might be nice to have a previous warning prior to getting that slow.”

Actually, AOA gives a warning as you approach the “critical AOA” (the point at which the wing will stall) regardless of airspeed. Remember you can stall an airplane at any airspeed. If you refernece AOA during maneuvers there is no need to worry about airspeed as AOA is unaffected by bank angle (load factor), or weight. Airspeed is a proxy for angle of attack and always lags. Better to focus on AOA than airspeed IMHO.

Point taken. Thank you. I wish it was easy to add an external AOA display that would be on top of the panel in my field of view. I have AOA in my landing checklist as a reminder.

 

[j4cbo]

You can also adjust the point (as as a percentage of the maximum AOA determined during calibration) where the beeps start, in the SYSTEM SETUP -> AUDIO SETUP menu. If the AOA beeps start too close to the stall, you can reduce that percentage a bit and get the warning “sooner”.

 

[tylerpattison]

I find the aural AOA beeps to be superior to just about any visual indication. Suggest your enable and try them if you have not already. Your milage may vary.

 

[BMW_X6M]

I find the aural AOA beeps to be superior to just about any visual indication. Suggest your enable and try them if you have not already. Your milage may vary.

Yes. I double checked my settings today. I have the beeps begin at 50% which is the bottom of the yellow (lowest setting) then going to a solid tone at 75% at the beginning of the red AOA.
The AOA tones have definitely helped prevent a stall in a few situations. I was concerned about bank angle at slow speeds as that also happened during a stressful attempt at landing in poor visibility conditions. During that banking maneuver I never heard the beeps so I still had some margin during that event. Thanks for the refocus on AOA!