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Stall Warning Horns

Cardiff Kook

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Sisters, OR
My cub doesnt have a stall warning (although the av30 has an aoa i need to hook up to audio panel.). 185 has a horn.

I watched the supercub.org presentation w Lori Nichols (thanks SJ!) and she talked alot about MCA and stall horns.

Havent paid that much attention to it in the 185 so i did a flight at altitude to go see when it activated.

In any flap setting except 0 flaps it would activate at about 58 knots. The plane wouldnt actually stall until well below that number (43 knots full at 30/40 flapsand 47 at 10/20, 63 at 0 flaps. Numbers maybe a bit off as i was trying to fly and watch the IAS.)

Lori recommends canyon speed somewhere just above stall warning (assuming stall warning works properly, 5+ knots above actual stall activation.). 58 knots seems very slow to me- i would probably bump it to 65 knots or 70knots, but anyways. Im still jot sure i was understanding why she called mca the same as the stall horn in the video which i rewatched several times)

My question is- does the stall warning activate at different times based on flap settings? Does the weight effect when it activates? Bank angle? Or is it just whatever IAS it was calibrated at?

At gross i think poh says stall speed is 52 knots at flaps 40- so maybe it is coordinated to that?

And yea, i know i should just “wear the airplane” and fly by the seat of my pants, etc, but trying to learn how this stuff works.
 
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The Cessna stall horn isn’t calibrated to anything. It’s a plastic reed that squeals when air is pulled through it. That’s why you suck on it to verify it works (then spit out a few bugs.) It’s adjustable so you can make it come on or go off relative to the stall. Mine does the normal pitch increase and stops a couple of mph above stall. That way I know the wing is lifting as long as I hear the horn and if it goes quiet I need to relax some back pressure.

Canyon turn training for me starts at 70mph and 20° of flaps. Tip it to 50° bank and pull elevator, and pull full flaps. My original instructor didn’t have me add more flaps but my current guy does. Find a good Skywagon instructor and explore what the plane will do. Never stop learning.
 
If you are trying to get somewhere, 80 kts and 20 degrees flaps works great for canyon speed in a 206.

I never go up valley where I need more than half to space to make the turn to an out...100% margin.

Level 45 degree banked turn to get out.

Panic turn is 60 degree bank and pull full flaps and full power in the turn.

Sent from my SM-G965U1 using SuperCub.Org mobile app
 
This kind of thread needs to be tempered with an ample dose of caution.

Cardiff, here’s a good article about steep turns. There’s a curve for utility and risk. For instance, at 50° bank the stall speed increases by 20%. At 60° it increases by 40%. That’s a big change for a little turn radius advantage. Guys in tune with that maneuver may be able to feel the wing about to let go. Most of us can’t. We call that turn a face bender because you’ll experience higher G than any other maneuver you’ll do in your Skywagon. It’ll feel foreign and you’ll never do it enough to change that. In that moment don’t trust your feel. Build in some safety. Your stall horn will be sounding. Get used to how yours is set and let it guide you when you don’t “feel” the airplane. Get some one-on-one instruction. I learn best by following examples so I like my instructor to show me rather than tell me. Bottom line, actual conditions are not the time to attempt your first face bender. Get training.

https://www.aviation.govt.nz/licens...training/flight-instructor-guide/steep-turns/
 
Am I the only glider pilot here wondering why airplane pilots are so intimidated by flying close to stall at high bank angles? It seems like a normal area of the envelope to me and and I go there any chance I can in the PA-28 or FX-3 if there is thermal lift to be worked.
 
Because we may fly into declining visibility under a cloud deck in a narrow mountain canyon? I’ve never once seen a glider in there.
 
But you said "It’ll feel foreign and you’ll never do it enough to change that."

So why not do it more and have some fun at the same time? Then it won't be a corner of the envelope where dragons lurk.

 
My instructor has us do them for coastal conditions, so the turn is done toward the mountain rather than away where we’d likely fly into cloud over water. That view of a mountain filling the windscreen while in a full power steep turn with Gs isn’t easy to train for in wide open spaces. It isn’t about flitting around in forever airspace. It’s about judgement coupled with technique. We have a ceiling, we can’t go down, and the lateral space is limited. I appreciate the training but I’ll never be comfortable with the situation. If you are? Good for you. Personally I don’t want Cardiff or anyone else to kill themselves for reading an internet thread.
 
Personally I don’t want Cardiff or anyone else to kill themselves for reading an internet thread.

If any low time pilot gets anything out of the discussion I hope it would be to become familiar with the corners of the envelope in benign conditions. If you don't go there when it's safe and easy you stand no chance when squeezed by ceiling and terrain.
 
My instructor has us do them for coastal conditions, so the turn is done toward the mountain rather than away where we’d likely fly into cloud over water.

Straying a bit from the main thread topic but that seems not only non intuitive but very dangerous. If there is space to turn toward the terrain I'd be flying closer to terrain and planning to turn away from it.

I'll take inadvertent IMC over CFIT any time.
 
This kind of thread needs to be tempered with an ample dose of caution.

Cardiff, here’s a good article about steep turns. There’s a curve for utility and risk. For instance, at 50° bank the stall speed increases by 20%. At 60° it increases by 40%. That’s a big change for a little turn radius advantage. Guys in tune with that maneuver may be able to feel the wing about to let go. Most of us can’t. We call that turn a face bender because you’ll experience higher G than any other maneuver you’ll do in your Skywagon. It’ll feel foreign and you’ll never do it enough to change that. In that moment don’t trust your feel. Build in some safety. Your stall horn will be sounding. Get used to how yours is set and let it guide you when you don’t “feel” the airplane. Get some one-on-one instruction. I learn best by following examples so I like my instructor to show me rather than tell me. Bottom line, actual conditions are not the time to attempt your first face bender. Get training.

https://www.aviation.govt.nz/licens...training/flight-instructor-guide/steep-turns/
Stewart, you are absolutely right, beware of internet advice.

50 degrees of bank sounds good to me at your 60 kt terrain speed. I would be gentler with bank at that speed too.

This is my recollection of MAF procedures that are aimed at keeping a proficient 500 hr pilot safe in terrain with a generous margin.

I could be wrong but I don't remember being able to stall the airplane in a 60 degree banked, level turn, pushing full power and pulling full flaps in the turn. I can't say if the stall horn even comes on?

This is a 180 degree turn to my "out". Entry speed is "80" kts although illusions in rising terrain will probably have already stolen some airspeed from the pilot who gets in this much of a bind.

Cardiff, decision making is everything as I'm sure you know. If there is any doubt that my turn radius will be less than half of the available space I do a level 180 degree turn at 45 degrees bank, in my 80/20 configuration. If I use more than half, I don't need to be there.. Time to fly down valley and make a new plan.

I don't think this is as close to the edge as it sounds. Should be safe for most pilots to experiment with at altitude as it is basically a steep turn with added stall protection.

Sorry for the thread hijack.

DJ

Sent from my SM-G965U1 using SuperCub.Org mobile app
 
Straying a bit from the main thread topic but that seems not only non intuitive but very dangerous. If there is space to turn toward the terrain I'd be flying closer to terrain and planning to turn away from it.

I'll take inadvertent IMC over CFIT any time.



And that's a good illustration of the importance of training. Do it where the potential for those conditions exists. The same is true for canyon turns. Instructors that live it know what to teach and how to teach it. Students learning it get to see what it looks like. That's an important component.

One of my first flights in my 180 was with Tom Wardleigh, who at that time had already slowed quite a bit with age. We were flying around the Colony Glacier and out of nowhere he pointed at the mountain next to us and asked if I could turn 180* toward that mountain. I tried but quickly aborted the turn because there was no way I would have made it. He calmly took the controls, bled off some speed, pulled some flaps, and made that turn like he had all of west Texas to do it. The lesson was to demonstrate technique AND judgement. My plane was bigger and faster than what I had come from and it required revisions to both. Much later in my life I was flying back seat with the best Cub driver I know. We were in the Denali Preserve looking for sheep and while approaching a notch to get into the next valley, we got absolutely hammered by the wind. Seamlessly he turn the Cub toward the mountain next to us to get us out of there. Turning toward the mountain got us mostly out of the full force of the wind and he made it look easy. Turning to the mountain wasn't intuitive to me but it was smart. It shielded us from the worst of the wind. The lesson I learned was that familiarity was a big factor. That move was intuitive for my friend.

Cardiff reminds me of that younger me. He's been flying a 135hp Supercub that's gross is lighter than his 185's empty weight. The 185 has 2-1/2 times more power, too, yet it has very similar wing area. Power loading and wing loading are dramatically different. My instructor friends say it's easier to train a Skywagon guy to fly a Cub than a Cub guy to fly a Skywagon. There's no question it's done all the time but the Skywagon requires some respect as it'll get a guy into situations he hasn't managed before. Training, training, training. My last two flights in my 180 were for training because I'm rusty and I need it. I never get too old or too proud to seek training.
 
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Seamlessly he turn the Cub toward the mountain next to us to get us out of there. Turning toward the mountain got us mostly out of the full force of the wind and he made it look easy.

You are making my point for me. If being closer to the terrain was beneficial then why not be here in the first place.

Glider pilots read terrain and visualize airmass movement. Many, perhaps most, airplane pilots fight the airmass.
 
To have an escape route. The point DJ was making all along. Enter the area like you'll need to get out. That's every mountain pilot's mantra. Never be surprised by what's around the next corner. Be ready.
 
Straying a bit from the main thread topic but that seems not only non intuitive but very dangerous. If there is space to turn toward the terrain I'd be flying closer to terrain and planning to turn away from it.

I'll take inadvertent IMC over CFIT any time.

Go fly coastal Alaska a while. Inadvertent IMC on Kodiak almost guarantees icing, assuming you’re going to climb to legal altitudes.

And, inadvertent IMC won’t be an option if you lose it in that turn before you CAN transition to IMC. Lots of folks have died trying to make that transition.

MTV
 
Frequent, I don't think anyone disagrees with you that turning away from terrain is the general rule. There are exceptions when the pilot must maintain visual reference at all costs. In those cases I'm hearing Stewart and MTV say it is more critical than ever to know turn radius intimately.
 
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Stall warning horns... fly several that just plane don't have them... out of those that do, most I can't hear. The one ship that has a visual enunciator (MVP 50 T) is more nuisance than I can tolerate, hence I fly it the least.

Get in, burn gas, and then burn more. Don't pick one instructor or mentor to hang your hat on, each has something to offer, and most have a different way of communicating. There are no short cuts to getting good at knowing your wing, and if you want to bank your life on the notion that the vane didn't get smashed one way or the other by a bird or a wash rag, a hole didn't get clogged by a mud dauber, or an electrical circuit or reed didn't fail, you'll never fly tight enough to have it do you any good anyway... Burn gas and pay attention when you do.

Confined turns... get in, burn gas, and then burn more. There are a lot of ways to skin this cat. How to cut the internet chaff from the internet wheat? Every time you practice a high performance turn, note the wind. Then when home (on the ground) look at a zoom of your ground track, measure it, and remember what that looked like in the air. 99.9999 % of forum users I have had conversation with about these things don't know how many feet it takes to turn an airplane, nor what that looks like from the cockpit. I'll just put this out there, until you get really, really good, it's going to take you 600' +/- at typical boondocks speeds. If you don't know how close that is from the air all the turn training in the world is a moot point. It just plain doesn't matter what you did with the instructor on board, because when feces hits the ventilator, you're probably not even going to know which shoulder the wind is on, and that in and of itself will cut in half or double your turn in the typical mountain flying weather.

Incidentally, I prefer not to make high G turns. Unless I screwed the pooch, most are done with three finger tips (although I do use flaps). To my mind a canyon denotes space up and space down, I'm not going to debate whether your turns should hold altitude or not, I'm just putting that out there to ponder, I do ALL of my flying 3 dimensional, I paid to fly in the sky, by God I'm going to use all the sky I need up, down, or laterally.
Adding power in a turn does everything we learned that makes turn bigger... When I really need to get it bent around I'm usually pulling power while giving it it's head, you can always come back in with power and recover lost altitude after you're spun around. None of that is meant to contest other posters here who have an established way of turning, it's just meant to illustrate the there's more ways to get this done than one, and the guy who thinks his answer it the only one, has only limited himself.

FF, You are not the only one. A local competitors jr. pilot was having a conniption fit over another local competitors senior pilot being too close to him while he sprayed :roll:, yes even we can't get away from the drama queens... kid scoots across the ground at 8' agl, That's within 8' of a solid mass, but shats his britches when another airplane is under a quarter mile from him.... :lol: You only have to miss the terrain (or an airplane) to be safely flying 8).

Flaps... there are several ways to use flaps, and each produces a different outcome. Even with respect to turning.
Most 'canyon turners' lay the airplane over, maintaining as much altitude as they can, and come in with power while pulling in on the flaps. They are loading the wing for all it's worth, and they have a very good reason to be concerned with both coordination, and stall speed. Because if it comes unhooked like that. it's gonna be exciting. When I train my pilots, they not only must slow the airplane down below flap speed, they must slow it down such that without flaps they would be falling. At this point flaps are nothing more than trim. They keep the airplane hooked in the turn and the back pressure down to finger tip level. Lose one like this and it will be like losing one in a benign falling leaf maneuver in your cub... And as a bonus, the plane won't care a bit how coordinated you are or aren't, although outrageous skids are just plain poor form and lead to bad habits... If you do lose one in a benign turn like this, you probably just need to burn more gas. Lot's more...

Take care, Rob
 
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The original Super Cub was not equipped with a “mechanical stall warning system”. Apparently, the manufacturer believed, and the airplane clearly demonstrated that the Super Cub wing offered ample aerodynamic warning of an impending stall, such that an additional mechanical Warner was not needed.

Now, imagine that: An airplane that offers such excellent aerodynamic warning of an impending stall that a “stall horn” wasn’t required.

At a couple points during its late production of the Super Cub, Piper ceased production of the airplane for a time. When the plane resumed production, some modifications were made….witness the metal flaps and ailerons, for example. And, in very late production airplanes, a stall warning system was also installed.

Now, the US Border Patrol had operated Cubs for decades, mostly at low level, slow and with flaps deployed…..man tracking was a big part of their mission. An old friend of mine was one of those pilots, with quite a few thousand hours in those Cubs. He told me that when the new Cubs started appearing on their flight line, Management concluded that those stall warning systems were a great idea…..so they retro fitted ALL their Cubs with those systems.

My friend told me, when I asked him what he thought about those systems, “Well, honestly, I don’t have an opinion on those mandated systems. All the pilots I know now carry a few wooden stick matches in their pockets when they’re going to fly a Cub. You stick one of those matches into the stall vane and break it off during pre-flight, then after you land, you use your pocket knife to remove the small chunk of wood.” This was delivered with a smile, and no apologies. This was a man who knew clearly how to function in a bureaucracy.

MTV
 
Some of our banner tow Bird Dogs had stall warning devices, I think the Ector versions and certainly our AgWagon did. Since we were always flying on the edge of a stall some of the guys would amuse themselves by rocking the nose up and down to play tunes with the stall warning horns. - Never me, of course. Seems like the breaker for the stall horn was always popped. I always felt that when flying on the edge, you didn't need to be distracted by a tooting horn. That aside, If you need it, use it!

We did rent a late model Cub with metal flaps and ailerons. Never felt quite right.
 
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Same with me towing gliders in the Pawnee, first thing after getting in is pull that stupid stall warning CB.


Sent from my iPad using Tapatalk
 
I've tried various flap notches over the years and settled on two.......25 and 50. Whether shooting coyotes ( in days past ) or shooting photos it was interesting to note that with flaps 25 at slower speeds the first visual stall indication was the lower door starting to rise.
 
The original Super Cub was not equipped with a “mechanical stall warning system”. Apparently, the manufacturer believed, and the airplane clearly demonstrated that the Super Cub wing offered ample aerodynamic warning of an impending stall, such that an additional mechanical Warner was not needed.

Now, imagine that: An airplane that offers such excellent aerodynamic warning of an impending stall that a “stall horn” wasn’t required.

At a couple points during its late production of the Super Cub, Piper ceased production of the airplane for a time. When the plane resumed production, some modifications were made….witness the metal flaps and ailerons, for example. And, in very late production airplanes, a stall warning system was also installed.

MTV
At some point in time during those Cub production down years, the FAA came out with a new regulation requiring a stall advisory system. I thought it was for newly certified airplanes and I recall at the time wondering why Piper installed the horn on an airplane which had been certified for years. Perhaps there were enough changes made (metal surfaces) that they determined one was needed?
 
At some point in time during those Cub production down years, the FAA came out with a new regulation requiring a stall advisory system. I thought it was for newly certified airplanes and I recall at the time wondering why Piper installed the horn on an airplane which had been certified for years. Perhaps there were enough changes made (metal surfaces) that they determined one was needed?

I could never understand it either, and I owned one. I would bet that some Dude with the word “Safety” in his title at Piper thought it’d be a good addition. But, who knows, Piper still had to deal with their “FAA Guy” as well.

MTV
 
FWIW my old 1948 Cessna ragwing 170 was not certified with a stall warning system.
But I'm pretty sure that it was required equipment for the 1949 C170A.
 
Cardiff asked about the stall horn in his new to him 185. If he goes out today to practice slow flight in this unfamiliar plane with more mass and more power than he’s accustomed to, having a properly adjusted stall horn is a great tool. If he flies around in a Skywagon with a clean wing at 60 mph doing turns and maneuvers I doubt he’ll have the feel to know where he is relative to stall, but the tone of the horn will allow him to fly with the knowledge of the wing’s lift margin. That’s a great tool. If I plugged most of the Cub drivers I know into my Wagon’s seat and asked them to do the same by feel they wouldn’t have the feel, and that’s a great reason to have stall indicators in airplanes.
 
...... having a properly adjusted stall horn is a great tool. .....

"Properly adjusted" are the key words here.
He describes his stall horn going off at well above stall speed, imho that isn't much help & in fact is detrimental.

The stall horn in my old C150/150TD did the same, I adjusted the switch & tweaked the vane as much as I could,
but it still went off way too soon-- distracting & not at all useful.
So the stall horn wiring accidently became disconnected between annuals.

The stall horn in my C180 goes off just a bit above the actual stall,
it actually is helpful and so it is still connected.
 
The point I've tried to make throughout this discussion and the one related to the current crop of so called "Angle of Attack Indicators" for single engine general aviation aircraft is simply that every pilot needs to fly his or her airplane at and close to the stalling angle of attack, in all configurations and attitudes, such that the pilot has a good feel for what that aircraft is like close to critical angle.

If your stall horn is not "properly" adjusted, it's a great idea to get it properly calibrated. As Hotrod points out, that's not always possible, but.... If you like gadgets, and want one of those "Angle of Attack" thingies, make yourself happy and install one.

BUT whatever you do, burn enough avgas at high alpha such that you KNOW what that airplane is telling you there....the FEEL of the airplane and the controls.....THAT can and will save your life at some point. And, it'll make you a better pilot.

I have flown with a lot of folks during flight reviews who are VERY reluctant to participate in slow flight and stalls. There's nothing to fear in stalls and slow flight, IF you've received proper training at high AOA to start with.

But, any time you may be looking for a "mission" (otherwise known as an excuse to go fly), saddle up and go fly that airplane at and beyond its limits, explore the flight envelope, safely, and after proper instruction there if you're not comfortable doing so.

Sermon over.....thanks

MTV
 
Cardiff, here’s the service manual page for my Skywagon’s stall horn. This from the 1969-76 manual. I’m pretty sure your stall horn is the same.
 

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My cub doesnt have a stall warning (although the av30 has an aoa i need to hook up to audio panel.). 185 has a horn.

I watched the supercub.org presentation w Lori Nichols (thanks SJ!) and she talked alot about MCA and stall horns.

Havent paid that much attention to it in the 185 so i did a flight at altitude to go see when it activated.

In any flap setting except 0 flaps it would activate at about 58 knots. The plane wouldnt actually stall until well below that number (43 knots full at 30/40 flapsand 47 at 10/20, 63 at 0 flaps. Numbers maybe a bit off as i was trying to fly and watch the IAS.)

Lori recommends canyon speed somewhere just above stall warning (assuming stall warning works properly, 5+ knots above actual stall activation.). 58 knots seems very slow to me- i would probably bump it to 65 knots or 70knots, but anyways. Im still jot sure i was understanding why she called mca the same as the stall horn in the video which i rewatched several times)

My question is- does the stall warning activate at different times based on flap settings? Does the weight effect when it activates? Bank angle? Or is it just whatever IAS it was calibrated at?

Angle of attack is what drives your stall horn. Critical angle of attack is altered by flap setting, which is why various AOA devices require adjustment at various flap settings. How much? that is subject with too many variables to be of any worth to this thread, but IMHO the difference is probably insignificant if you require the use of any of these devices. Because if that shoe fits, you are typically padding the airspeed with more than the flaps change it. Weight and bank angle do not change your Critical angle of attack, but do change your stall speed, which is probably where confusion starts to set in with a pilot who doesn't eat live and breath all things flying (and there is certainly nothing wrong with that).

At gross i think poh says stall speed is 52 knots at flaps 40- so maybe it is coordinated to that?

See weight portion above

And yea, i know i should just “wear the airplane” and fly by the seat of my pants, etc, but trying to learn how this stuff works.

The reason old impatient curmudgeons push this is because through experience they have learned that not only are these devices subject to many errors in adjustment and function, they require proper interpretation which is sometimes confusing and akin to black magic. For what? a margin of 10 mph? That is a tremendous margin if your trying to cut things fine, which is exactly what most people are expecting to do with any of these. Having said that, most of those old crotchety farts spent more time requiring performance out of a wing than the real life majority of end users.... So ya, great tools when used and adjusted correctly, for users that use them correctly. For the guy that has the time and desire to burn gas and sit up & Pay attention while he's doing that, they are a moot point at best, and a distraction at worst.

Take care, Rob
 
I've tried various flap notches over the years and settled on two.......25 and 50. Whether shooting coyotes ( in days past ) or shooting photos it was interesting to note that with flaps 25 at slower speeds the first visual stall indication was the lower door starting to rise.

That was the great thing about flying Stearmans. Eery single one we had, regardless of engine size would shake the stick gently but noticeably just before the stall, and the fabric on top of the lower panels would ripple. Maybe that's how they got the idea to install stick shakers as stall warning on airliners.
 
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