Thoughts on the reed-style stall warning devices?

[guidoism]

I’ve come the portion of the build manual where it mentions the optional Vans stall warning device and I was just about to buy it, but I’ve hesitated since it doesn’t make much sense given that I’m going with an AoA system.

This is my thinking:

- The vast majority of the time when my engine is running and my electrical system is working I’m going to be using the electrical AoA on the G3X or whatever EFIS I choose
- I am leaning towards having a small subset of instruments that work without electrical power in case of full electrical failure. I will have: 1. The compass (which is legally required anyways), 2. A purely mechanical ASI, and 3. A purely mechanical altimeter.

I would like to also have a purely mechanical: 1. AoA (such as the Lift Monitor) and 2. Aural (reed-style) stall warning.

My reasoning behind the aural stall warning is that during an electrical failure I’ll probably be pretty distracted and just want another layer of safety to keep me from stalling. And honestly, I like the sound of the stall horn during flare.

The Vans stall warning device adds practically nothing because the electric AoA’s beeps will be better than the Vans device and under completely electrical failure it’s not going to work either. I guess the only place where the Vans device adds something is EFIS failure and having something that works on the initial flights before I’ve configured the AoA.

Thoughts?

Any reason this is a stupid idea or a waste of time and panel space?

Has anyone else installed a reed-style stall warning system?

 

[Carl Froehlich]

No. The SkyView AOA provides this function and more.

An it will not catch on your leg!

Carl.

 

[skelrad]

I don't know that there's a right or wrong answer; probably more just preference than anything. My wing came with the pre-punched hole and the kit included the stall warning stuff. I'll be filling the hole in the wing and won't be installing the vane. With an AOA in the glass panel (I'm using AFS), I don't see the need for a backup stall warning (plus I think the combo of the aural AOA warning on top of an aural stall horn warning would drive me nuts). In terms of electrical failure, that goes well beyond the stall device decisions. I went the route of a backup battery for my AFS screens, backup battery on my G5 (which in itself is the backup to the AFS ADAHRS) and backup alternator. I originally thought about mechanical instruments as a backup, but the small devices like the G5 or equivalent aren't much more expensive than the instruments they replace, and more capable anyway. Check on the reg for a compass - if you go glass, you'll have a magnetometer. Pretty sure you just need a "magnetic direction indicator", not a wet compass.

 

[planenutz]

The reed style of stall warning system is cheap, light and reliable but I'm not sure there is any weight advantage between that and a vane switch in the end. I'm not sure either is better than the other. The big question I'd be asking is - do you really need either?

If you have a total electrical failure and have no AOA or EFIS then remember that you still have one very good indicator remaining - seat of your pants. Once you have a few hours in the aeroplane you'll find you can feel what is happening quite well without needing any of these other devices.

Keep it light and uncomplicated.

 

[blaplante]

I’ve come the portion of the build manual where it mentions the optional Vans stall warning device and I was just about to buy it, but I’ve hesitated since it doesn’t make much sense given that I’m going with an AoA system.

This is my thinking:

- The vast majority of the time when my engine is running and my electrical system is working I’m going to be using the electrical AoA on the G3X or whatever EFIS I choose
- I am leaning towards having a small subset of instruments that work without electrical power in case of full electrical failure. I will have: 1. The compass (which is legally required anyways), 2. A purely mechanical ASI, and 3. A purely mechanical altimeter.

I would like to also have a purely mechanical: 1. AoA (such as the Lift Monitor) and 2. Aural (reed-style) stall warning.

My reasoning behind the aural stall warning is that during an electrical failure I’ll probably be pretty distracted and just want another layer of safety to keep me from stalling. And honestly, I like the sound of the stall horn during flare.

The Vans stall warning device adds practically nothing because the electric AoA’s beeps will be better than the Vans device and under completely electrical failure it’s not going to work either. I guess the only place where the Vans device adds something is EFIS failure and having something that works on the initial flights before I’ve configured the AoA.

Thoughts?

Any reason this is a stupid idea or a waste of time and panel space?

Has anyone else installed a reed-style stall warning system?

Many of the EFIS options have included or optional batteries for backup.
So, with full electrical failure you might still have some AOA / stall indications.
The uAvionix AV-30, and Garmin G5 spring to mind, I'm sure there are many others.

One contrary bit of opinion... I guess only low time in type pilots stall/spin in the pattern? http://www.kathrynsreport.com/2020/11/vans-rv-4-fatal-accident-occurred.html ... formerly tied down just across from my hangar. Not a low time pilot, not low time in the plane.

 

[GaryK]

Many of the EFIS options have included or optional batteries for backup.
So, with full electrical failure you might still have some AOA / stall indications.
The uAvionix AV-30, and Garmin G5 spring to mind, I'm sure there are many others.

One contrary bit of opinion... I guess only low time in type pilots stall/spin in the pattern? http://www.kathrynsreport.com/2020/11/vans-rv-4-fatal-accident-occurred.html ... formerly tied down just across from my hangar. Not a low time pilot, not low time in the plane.

I have both the reed style stall warning and the Garmin AOA on the G3X in my Cub. They both do the job but the AOA on the G3X is much more customizable.

 

[rolivi]

The compass (which is legally required anyways

Where is this coming from? The magnetomer for your EFIS satisfies this.

leave the vane out and you'll find that AoA and Seat of Pants will be fine. Although I will say when I flew a cherokee I always flipped the vane after each flight to confirm I hadn't left the master switch on.

 

[Ironflight]

…..The compass (which is legally required anyways)…..

Yeah….point of order….for Day VFR there are NO instrumentation requirements for an aircraft with a Special Airworthiness Certificate 9of which, E-AB is one). For Night or IFR, the requirements of 91.205 will be made applicable by your Ops Lims…and then, yes - an EFIS magnetometer will satisfy the requirement for a “magnetic heading Indicator”….

Back to the OP’s question - I have multiple AoA’s in all our aircraft, not because I feel that I need redundancy, but becasue I seem to have ended up in the role of “AoA System Tester” for the industry. It is annoying to have multiple audible inputs from different systems, so I would not want a stall warning going at the same time as the AoA because they probably won’t be properly synchronized. Anyone who has ver read my stuff knows that I am a huge cheerleader for AoA….but I really think that pilot’s should be competent enough to fly without it in the case of failures that take it away. If not, then we need to talk about your THIRD redundant system, and how you are going to turn of the one that is out to lunch…after you determine which that is…. AoA is very useful for pilots who are getting a little distracted in the pattern - If you have failures that take away your AoA, I think you’re going to be very attentive to your flying.

I’d place redundant AoA/Stall warning systems on my list AFTER redundant engines ….

 

[guidoism]

Yeah….point of order….for Day VFR there are NO instrumentation requirements for an aircraft with a Special Airworthiness Certificate 9of which, E-AB is one). For Night or IFR, the requirements of 91.205 will be made applicable by your Ops Lims…and then, yes - an EFIS magnetometer will satisfy the requirement for a “magnetic heading Indicator”….

Back to the OP’s question - I have multiple AoA’s in all our aircraft, not because I feel that I need redundancy, but becasue I seem to have ended up in the role of “AoA System Tester” for the industry. It is annoying to have multiple audible inputs from different systems, so I would not want a stall warning going at the same time as the AoA because they probably won’t be properly synchronized. Anyone who has ver read my stuff knows that I am a huge cheerleader for AoA….but I really think that pilot’s should be competent enough to fly without it in the case of failures that take it away. If not, then we need to talk about your THIRD redundant system, and how you are going to turn of the one that is out to lunch…after you determine which that is…. AoA is very useful for pilots who are getting a little distracted in the pattern - If you have failures that take away your AoA, I think you’re going to be very attentive to your flying.

I’d place redundant AoA/Stall warning systems on my list AFTER redundant engines ….

I don't have enough money for redundant engines... But points taken from everyone: Focus on flying skills and the normal case, not absurd scenarios that won't likely happen.

 

[wirejock]

Just a different opinion.
I have Dynon with AOA and the Vans stall vane. The Vans stall switch is wired to a 12V Piero buzzer with a volume pot. Power is from a small fuse block fed from the Master Contactor. It also has two circuits for the P-mags.
It took a few flights to get them synchronized. It's probably unecessary, but I like the idea. It does have a single point of failure if the contactor fails.

I also fly with a tablet running AvareX connected to Stratux and a Garmin D2 watch so maybe I'm belt and suspenders.

 

[justa6ereh]

To me, they are no different than having an automatic transmission, or any of a thousand other little gizmos, all designed to make life easier…soon the easier disables the previous ability to contend with a given issue…

I’m glad for everyone who uses these devices, as none of you need to learn to shift an 18 speed Eaton Fuller transmission, use a clutch, select a gear or really pay attention to much of anything…follow the magenta line, no need to look outside, let the box tell you when danger is closing in on you.

I’m also glad that to me they are useless, as I developed a skill that doesn’t need them, let alone trust them or rely on them.

Yes, my third wheel is on the back of every airplane I own….don’t own a fadec system…don’t talk to AI devices and have no interest in a box beeping, or squealing, flashing or doing anything to interrupt my well rehearsed landing game plan.

And when they fail…I truly hope, those of you with triple redundant systems remember that the Wright Brothers learned to feel it….if my airspeed fails…? who cares…I’m looking outside, experiencing my flight and honing skills, learned long ago, that are as valuable today as when they were learned.

Crutches…un-necessary unless you have a broken bone, but that’s me. If you like the cost, weight, another piece to keep an eye on, concern over whether it’s telling you the correct information, investing time into more settings and parameters and all the delightful stuff that many seemingly enjoy…enjoy the process!

I’m gonna go fly and look out the window and do some rolls and loops and fly just for the pure fun of flying.