Stall Horn + AOA?

I am planning to have an angle of attack (AOA) indicator in my 10, so I figured I'd poll the VAF family to determine whether I should ALSO install the Vans supplied stall horn microswitch. Seems like it might be a good backup, if it can be used in conjunction with the AOA, but maybe it's extraneous and/or adds confusion, when flying using the AOA... What say you, VAF'rs? AOA only or AOA + Stall Horn?

Interesting question. It really depends on your ability to recognize the stall.

My first airplane didn?t have any type of stall warning (?41 T-Craft) and I never missed it. My RV-9 did not have a provision for a stall warning of any type, other than the pre-stall buffeting, which is most noticeable.

However, if my kit came with the pre-punched holes for the stall warning, I would install it.

The Dynon?s I have installed (First a D100, later replaced with a SkyView) both had AoA alarms. While not needed, I?m very happy to have them and have flown short and soft field approaches with the AoA just starting to alarm.

Given the choice of just one, I would go with the AoA. The thing that will drive you crazy, if you install both, is that they will come on at different times since they are measuring different things.

I put the stock Vans stall warning in, as well as a Dynon D6 driven AOA.
Plus for Vans unit: it works from day one. D6 AOA needs to be run thru a calibration procedure.
Minus for Vans unit: (1) need to be everafter careful with wing not to bend the stall tab. (2) with noise attenuating headsets I can barely hear it. Buzzer is near my left knee.
Plus for Dynon: I like the audio tone in my headset, slowly beeping at the yellow and becoming ever faster as you approach red.

If I were doing it again I think I would leave the Vans stall sensor off. But if I did put it in, I'd wire it to a tone generator and feed it into my audio panel, as well as the Radio Shack buzzer.

I'm using AOA in my -10 but went ahead and installed the horn switch and wired it up. If it causes any confusion I will remove it. FWIW, I did not install the switch and reed permanently until after I painted my wings but the wires were ran and connectors installed. I installed the switch and reed when the paint cured and the wing was still up on the painting rig. It was a real bear getting those things installed and that alone took a couple hours and a lot of frustration and cussing trying to work through that small access cover hole. If I were to do it again, I would install the thing before the wing gets closed up and deal with the reed sticking out. Overall I am glad I decided to put it in though.

You have to remember some basics.

Stall is predicated on AOA - at any speed.

AOA is affected by stick position

Every time you have the stick back in your gut, ask yourself this.......

Why am I doing it, am I happy where I am and do I know I am close to a stall?

In fact, here is a thought - If you 'of stature', perhaps you have a built in stall prevention system

When I demonstrate turning, nose below the horizon stalls to guys, they are enlightened.........

All the RV's I have flown have had benign stall characteristics, however some don't announce their proximity to the stall via buffet.

I fly Dynon, with AOA and when you need to pay attention going into a short strip, the ladder system works really well.

Fly the ship, use AOA.

9GT said:

It was a real bear getting those things installed and that alone took a couple hours and a lot of frustration and cussing trying to work through that small access cover hole.

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This is exactly the reason I want to know about reasons for or against having it installed with AOA. I don't want to go through the headache if it's simply not as good (or detrimental) when you have AOA on an airplane.

No AOA and rarely hear the stall horn with ANR's. It does not take long to get the feel of it and I practice stalls on almost every flight with and without the family. Your reactions become instinctive. Sterile cockpit rule and pay attention. My copilot knows our minimum approach speeds as well. I would install both and install a toggle switch in case EFIS goes out or just disconnect after AOA is calibrated.

I have both, but can bearly hear the stall warning horn with my Lightspeed headset. If I was doing it again I would either leave the stall warning out, or use a louder horn with it.

Jim Berry
RV-10

Both

I'm planning on installing both. I have the stall warning in my wing already, still deciding on which AOA indicator to use. I may roll my own - one that would read out AOA in 1 degree increments.

ppilotmike said:

This is exactly the reason I want to know about reasons for or against having it installed with AOA. I don't want to go through the headache if it's simply not as good (or detrimental) when you have AOA on an airplane.

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This is a non event if installed from the backside of the leading edge, while in the cradle, before the leading edge is fastened to the wing. A one night task so to speak.

Dynon AOA

I have the Dynon AOA & no stall warner. The audio output on the Dynon changes to solid tone a few knots above the stall, so it is a stall warner also. Additionally it sounds through the intercom so you can still hear it clearly with an ANR headset on.

I'll have both

I'm not flying yet, but I have already installed the Vans Stall warning (my leading edge came pre-punched for it), and the dynon pitot with AOA (planning the Skyview) in the wing.
My thinking is that if the skyview fails I'll have the stall warning as a backup.
Remember that when things go wrong (such as a skyview failing) the pilot's attention can shift very quickly on trying to troubleshoot/fix the failure from the rest. And this can happen to anyone. In this case the basic stall warning could be very useful in a critical phase of flight (initial climb or final approach).
I will calibrate the Vans stall warning to come on just a couple of knots below the Skyview AOA warning.

The stall warning vane is part of the RV14 wing kit with a hole pre-punched for it. I've filled that hole and will sell the stall warning vane assembly to anyone interested at a good price (not sure what its worth). I have an analog AOA that I will mount into my glareshield, ala tach gage on a '69 GTO, making my otherwise modern Garmin cockpit look a little retro.... I had this setup on my RV6 and really liked it being in my field of view on landing. My current RV8 has the Dynon AOA/pitot, with AOA displayed in the EFIS and I seldom look at it because its not where I can easily watch it. A good AOA system will probably enable you to fly an approach more precisely, but you really don't need anything but airspeed to fly safely.

I skipped the horn

I'll just be using AOA. I skipped installing Van's stall warning system.

In fact I'm just now in the midst of installing Dynon's heated pitot/AOA. If you go this route DO NOT install the pitot mount in the same position as Van's has the pitot in the plans which is one bay inboard of the bell-crank. Go at least one bay outboard. The aileron push tube is causing me great amounts of grief routing the pitot lines so that everything is secure, well clear of the push tube and the pitot is still "easily" removable.

Stall Horn sound in headset? Auto toggle using VP?

I had not even thought about "not hearing" the Vans stall horn. Is there a way to tie it into the headset too? I also wonder if there's a way to use a Vertical Power unit to automatically switch the stall horn if there's an EFIS failure, but keep it off all other times, so I don't have two "alarms" at once.

ppilotmike said:

I had not even thought about "not hearing" the Vans stall horn. Is there a way to tie it into the headset too?.....

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I bought one of the stall warning kits from Van's for my RV-3B and it has a circuit board as part of the kit which has a connection labeled "audio mixer/audio input." The only other connections are power, ground and ground from the microswitch. I think the part number for the PWB is ES AUDIO WARN, named: audio warn assembly.

It needs a 2 a circuit breaker.

The PWB is small, about 1.5 inches square and about 5/8" thick.

Dave

The normal complaint with The stall Warner is it is to loud. You may want to check how you have it tied into your audio system

I was concerned about seeing the Dynon AOA display on my Skyview. But then I flew with it. The higher the AOA, the faster-pitched the beeping is in the headset. Do it a few times at altitude all the way to stall to calibrate the sound and display to your brain. I never even look down at that indicator on final approach anymore, because the beeping sound is so useful. You can get it beeping fast (and at an airspeed you are comfortable with based on winds) while still high, then ride that beeping rate all the way down with pitch, keeping your eyes on the runway all the time and adjusting power as needed (usually all the way off on the -12). I am practicing to be using a 1260 foot strip so slow approaches and precision touchdown placement is a must!

I have an RV-12. Per the ASTM Cert Standards, it comes with a stall warning vane and system. The warning horn sounds through the headest, and is LOUD (and annoying.) There is also a Red Lite on the Skyview display. The horn comes on about 7 kts above the stall.

I trained on the RV-12 with Mike Seager down in Oregon. We made 8 flights. He put masking tape over the stall warning vane and it never sounded. I don't know if he did that to increase my sensory perception of the stall warning characteristics, or because he felt listening to that raucous horn was a PITA. If the airplane (the Vans Demonstrator) had an AOA installed - I don't know. If so, it was not enabled.

I'm a believer in AOA, so when I built my airplane, I incorporated all the plumbing for the AOA system. After I got my FAA certification, I simply activated the system on my 2nd flight. I calibrated it a few times per the instructions on flights 2 and 3. As noted by others, in addition to the indicator chevron, it beeps at you.

I had no previous experience flying a light airplane AOA. I immediately fell in love. Now the problem became the TWO systems working in parallel. The Dynon AOA with its gentle beeping vs the raucous vane activated buzzer. The buzzer generally wants to come on first, and the sound wants to overwhelm and cover up the AOA tones. (Like the old joke of the pilot who lands with the gear up and tells the Tower he didn't hear their warnings because of the loud buzzer.) It's also a little bit jarring if it comes on suddenly and unexpectedly during the final approach and landing phases.

I was gonna post on this subject on the RV-12 Forum, but a search led me to this thread. Right now, I'm seriously considering deactivating the vane buzzer and just going with the AOA. It seems more precise, guiding, gentle.

Actually, I think Vans should include the AOA in the Plans, so it doesn't have to be installed as a post-Cert mod. After all, the Skyview and its ADAHRS are all set-up for the AOA system.

As to the comments about having them both for redundancy, in addition to deactivating the stall warning vane, Mike also completely shutdown the Skyview (he said I was looking at it too much), and made me fly a series of take-offs, circuits, and landings with nothing but my eyeballs and throttle for maintaining airplane attitude and speed control. He later said they were some of my best flights. I don't know about that, but I felt remarkably comfortable flying the airplane with absolutely no instruments. I recommend it as a valuable exercise for all pilots.

Bob Bogash
RV-12
N737G

Just came up

This topic just came up on a conversation with Jason at Aerotronics (panel is currently under construction with them). I installed the Vans stall warning vane as well as the AFS AOA. We are going to have the AOA give me an aural warning through the headset and the Vans stall vane give me a visual "STALL" indication on the AFS EFIS. I figure this will:
1) avoid the nuisance of two aural warnings overlapping and raising my blood pressure
2) have a redundant stall warning system with each driven by a different source (vane vs AOA)

It seemed to make sense to me.

David

Cannot answer Poll since "neither" is not an option