SV Airspeed Tape Issue

[alibi7]

I was flying with a friend on his RV7A. I noticed on his GRT EFIS speed tape that on approach you could see the tape was red below his stall speed. On taxi in the numbers were also in red. I am not getting that feature on my Dynon SV. I only see white on my airspeed tape at low speeds. I see yellow then red when I get close to VNE. In the Menu page I have set all my Airspeed Limitations. Am I missing a setting somewhere?

 

[dynonsupport]

No, you are not missing a setting.

Does the GRT calculate the stall speed dynamically, based on flap setting and wing loading? Or is it just a set value, which seems less than safe.

For awareness nearing stall you really want to depend on your AOA indicator, in particular the audio alert.

-Robert
Dynon Avionics

 

[dynonsupport]

This has been discussed in the past as well:

http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1394589433/0#0

There is an AC for certified airplanes that suggests this is a good idea, but it also requires it not show while on the ground since RED in aviation means something is absolutely wrong right now and you don't want to train pilots to ignore it, so the simple implementation isn't right either. It's on our list for, well, someday, but there hasn't been a lot of interest.

The other tradeoff is that it's never quite right, since you have to set it at a fixed speed and the configuration and weight of the aircraft matters.

 

[vlittle]

No, you are not missing a setting.

Does the GRT calculate the stall speed dynamically, based on flap setting and wing loading? Or is it just a set value, which seems less than safe.

For awareness nearing stall you really want to depend on your AOA indicator, in particular the audio alert.

-Robert
Dynon Avionics

I think underdog is under-equipped.... No AOA.  He said that his 747 didn't have one, so neither does his RV-7 tail dragger.  I would point out, however, that the '47 has a nose wheel.

Vern

 

[alibi7]

We are dealing with a safety issue here. The airline check departments have spent countless time and energy trying to keep pilots safe. It is cute to have all the bells, whisles and toys that Dynon provides from pilot requests. A lot of it does not address the safety aspect. Red is used in heavy metal airplanes...it gets your attention. Bells and suddle tones are also used. I know on base to final/approach and on profile my attention is focusing on the envirment ahead, I want to be insured i will not fall below the critical zone. Red gets my attention. I hope Dynon never varies from the true aspect of aviation....Keeping pilots safe.

 

[dynonsupport]

The AoA that all Dynon EFIS systems support and have since 2003 has a visual and audio alert for the stall, which is much more accurate than a fixed red pointer on a tape with no audio alert. At $200 it's a superior and affordable safety device that we hope all pilots that are concerned for safe operation of their aircraft will purchase and install.

 

[gtae07]

I'm pretty sure the 747 does have AOA, though it may not be displayed to the pilot.

We are dealing with a safety issue here. The airline check departments have spent countless time and energy trying to keep pilots safe. It is cute to  have all the bells, whisles and toys that Dynon provides from pilot requests. A lot of it does not address the safety aspect. Red is used in heavy metal airplanes...it gets your attention. Bells and suddle tones are also used. I know on base to final/approach and on profile my attention is focusing on the envirment ahead, I want to be insured i will not fall below the critical zone. Red gets my attention. I hope Dynon never varies from the true aspect of aviation....Keeping pilots safe.

As others stated, AOA is exactly that safety item.  Your fixed red section of the airspeed tape is only accurate in 1g flight at whatever weight you tested your stall speed; the AOA will be accurate at any weight and any g-loading.  On your base-to-final turn there's no more guessing of the "well, I'm at this angle of bank, so maybe my stall speed's 10 knots higher, so I think I have this much margin..."  With AOA, you know how much margin you have--no guessing.

I'd give this document a read: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140011419.pdf

 

[alibi7]

Ya, thanks for all that input, especially from Dynon. Got lots of attention on this one. Vern X told me to paint a red line on the side of the Efis tape. On all heavy metal airplanes that I flew, they all had Angle of Attack indicators. There was no stall indication on the panel. The attack indicator was referenced to the Stick Shaker..sure got your attention.....which brings up another point......

 

[65xx]

I 100% agree with Dynon reply #1, concerning AOA audio alerts on the base turn to final and (added) in the landing flare. Mongol say "AOA Good". However, I would like to see a slight change in the AOA audio though. I would like optional voice prompts starting a "approaching stall" to a final stern "STALL! STALL!, LOWER NOSE " (ending with some sort of mild profanity). My mother's voice strangely comes to mind. Dan

 

[dynonsupport]

Dan,
If you use the Tone for AoA, not voice, then it is a progressively more aggressive tone as you approach the stall. It's hard to do with voice since saying "Approaching stall" can take so long to say that you may have moved on to a full stall by that time.

 

[krw5927]

The attack indicator was referenced to the Stick Shaker..sure got your attention.....which brings up another point......

Ask and you shall receive. Ironically, also one of Vern's inventions:

http://makerplane.org/?p=1939