Stall in a turn

[raytoews]

I have been having a spirited conversation with a couple of friends about stalls during a turn.
I have seen it in other articles that say the upper wing stalls first.
It is not logical to me.
I am assuming a stabilised turn, no aileron input and co-ordinated rudder.
There should be no reason for the upper wing to stall ahead of the lower.
Apparently common wisdom is the upper wing will stall in a climbing turn and the lower wing in a descending turn, although how you would stall in a descending turn I don't understand. Most general aviation aircraft are not capable of a pitch up.
I read an article about the staircase effect and it didn't seem conclusive.
Is this another one of those arguments,,,,like the up wind down wind turn nobody seems able to prove or disprove.
I don't have an aircraft I care to spin so am reluctant to go out and try it.


Is this splitting hairs?

Someone set me straight on this one.

Please.

[FlyingRon]

I agree with you. All that matters is ANGLE OF ATTACK not whether the aircraft is turning or climbing or which wing is "higher."
Now the wing on the outside of the turn is going to produce slightly more LIFT because it's going a little faster, but in coordinated flight (even in a turn) the AOA should be the same. Even that lift change is going to be negligible.

[Bill Berson]

The upper wing should stall first if you are holding the wing up with aileron. Because that barn door aileron changes the stall angle of attack to less than normal. So a wing normally stalls at say 15° neutral and say 12° with the aileron deployed down.
Many modern airplanes have this tamed by design. But old designs are still sold under old rules.

[DRGT]

When is a stabilized coordinated turn, lift is the same on both wings. Assuming the horizontal lift component is exactly equal to CF (virtually impossible assumption, but that is the definition of coordinated flight), both wings will stall at the same time.

[Bill Berson]

Lift is the same, but each wing can have a different aileron configuration to make that equal lift. Different configurations stall at different angles. Then torque, prop effects and everything else, it's a stretch to make broad one size fits all statements.
Thats why the topic is so involved and pilots keep killing themselves.

Post one said assuming no aileron input. But usually there is aileron input because the outer wing is moving faster. Aileron input can trigger the stall or prevent stall, just depends.

[DRGT]

Lift is the same, but each wing can have a different aileron configuration to make that equal lift. Different configurations stall at different angles. Then torque, prop effects and everything else, it's a stretch to make broad one size fits all statements.
Thats why the topic is so involved and pilots keep killing themselves.

Post one said assuming no aileron input. But usually there is aileron input because the outer wing is moving faster. Aileron input can trigger the stall or prevent stall, just depends.

Believe it or not, I agree in general with what you are saying, but the variables you rightly mention are negated by the OP's original assumptions. I also agree in those assumptions can only hold true in an academic discussion. Torque, prop effects, and control configurations, etc all have an effect in the real world.

I also agree that many pilots have insufficient knowledge in this area. Note my thread on LOC - spins. The FAA and AOPA and many other "experts" publish so a lot of false/misleading information. Primary flight instructors rarely teach anything beyond what they have read in a book or have been told. That is, they lack the experience to sense what is happening with the airplane (slip, skid, high angle of attack, etc.) and therefore lack the capability to pass on needed skills to students. I submit the lack of these fundamental knowledge areas and skills is the reason why pilots continue to kill themselves.

[Bill Berson]

Totally agree, there is a lack of knowledge and recent experience flying while slow in turns to train the correct reaction to a stall in a turn. I do a lot of turning in gliders with frequent turning stalls.
And I read Stick and Rudder again each year.
The recent Sport Aviation had a comment from a prominent expert, but I didn't want to reply and confront an expert.

[FlyingRon]

Don't get me started on the FAA. Their definition of coordinated flight defies explanation.

[vaflier]

Years ago I went for some aerobatic training and just plain fun in a Great Lakes Biplane, after loops and rolls and spins the instructor told me there was one more thing he really wanted me to see as he felt ALL pilots should see it. It was the classic base to final turn Stall. He had me climb to 4 thousand feet and set up as though we were landing at 3200 feet. We flew downwind , base and at the turn to final he had me fly it as though we overshot the turn and then try to bring it back to centerline. While in the left turn we turned steeply to bring it around and held the nose up a bit. I was expecting it to roll over to the left into the turn, BOY WAS I WRONG !!!. It snapped over to the right and immediately went into a steep spin. If we had actually been landing at the time we would have left a large smoking hole. I was amazed at how quickly it happend and that it went over on the right wing ( the higher wing ) and immediately spun. There was no time to even react , for a moment I was simply baggage and not a pilot. IT WAS PROBABLY ONE OF THE BEST LESSONS I WAS EVER TAUGHT AND IT LEFT A HUGE IMPRESSION. I now know how pilots crash turning base to final.

[Bill Greenwood]

vafier, Its good you go the spin recognition, but not that way. It was dangerous, first 4000 feet is low to be doing and intentional stall and spin. A full spin can take two turns to recover and get the nose back up to level flight might take 2 or 3000 feet. And you dont say if you had parachutes, and if not your survival was dependent on a full recover. I have flown a Great Lakes some years ago and I recall it handling well, but not all planes would be so benign. A T-6 probably wouldnt and the pilot manual for a P-51 firmly says spins are not to be started below 10,000 AGL.
As for direction, sounds like you had extra aileron into the turn, and not enough rudder to stay cooridinate, thus the outside wing was lagging and stalled first and you rolled over the top. If you had to spin the over the top way may give you a few seconds more to recover whereas tuckng under might happen even quicker.
Spins are not to be taken lightly, I wanted to see how my plane spun and recovered. I read the Pilot Notes, no extra caution noted and I asked the factory test pilot who said he expected it to be normal. I went to 15,500 over Fond du Lac and did a spin and recovery in each direction. It was normal but still I would nt want to have it happen at a few thousand feet.
My friend Jay Cullum made a video of spinning his P-51 and he did it from 17,500 feet near Dallas.

[WLIU]

As with many aspects of aviation, it is important to not assume that how your airplane performs is how all airplanes perform.

The Great Lakes recovers fine from a spin. Does not take two turns. A spin from 4000 AGL is not hazardous in that airplane. And parachutes are specifically NOT required when doing spins with a CFI (see 14 CFR 91.307 and the recent clarification by the FAA Office of Chief Counsel).

Assumptions and one-size-fits-all old wives tales tend to not be constructive.

Thanks,

Wes

[Bill Greenwood]

If for some reason the CFI who has gotten a student into a spin from 4000 feet was not able to fully recover, it would be very comforting just before they hit the ground to know that Wes and 14 CFR 91.307 says "parachutes are specifically NOT required when doing spins with a CFI." It would be especially reassuring that an FAA lawyer also confirmed that the foolish practice of doing spins at low altitudes is full legal. I wonder how much spin recovery experience the lawyer has and how many, if any bailouts he has without a chute.
That silly and overcautious P-51 pilot at Duxford was saved a few years ago by having a chute and using it below 1000 feet after the Skyraider pilot hit him in a formatioin. But then again maybe he didnt have an FAA lawyer to reassure him about flying without using a chute, it would have been perfectly legal.
Just before the Titanic hit the iceberg resulting in the death of about 800 people, they were fully legal and in full compliance with FAA ( British board of trade ?) regulations, is leaving harbor with lifeboats for less than half the passengers. It must have been very comforting for Capt Smith to watch women and children, not to mention men , face certain death in icy water and know they were legal. By the way, I am sure you can recover from a spin in a Great Lakes in less than two turns and 4000 feet , just as I did, So why worry about anything/ Capt Smith, in his previous 25 years of sea duty had never hit an iceberg before so why carry enough lifeboats?
And Wes, I am trying to be polite, but also make a point, It is foolish to advocate doing low altitude spins without chutes, and if I am not constructive in pointing that out so be it.

[WLIU]

I am also being polite. We do spins in Great Lakes and similar aircraft in the contest box below 4000' very regularly. I did 2 just this weekend during competition flights.

Please be very careful projecting your knowledge into areas that you do not have direct experience in. I promise not to spin a P-51 below 10,000'.

Thanks,

Wes

[Bill Greenwood]

Wes, when you do spins in a contest box below 4000 ft do you have a student with you flying the entry to the spin, and that student someone who is new to spins and the plane? And do you wear a parachute in the contest box? And when and where do you do these in the Great Lakes, just curious since I havent seen them much in contest.
P S I dont have direct experience in lots of things, skiing in avalance closed areas , racing motorcycles without a helmet , snake handling as part of church services, etc. But I wouldnt do these things nor would I encourage others to do them, legal or not. There are lots of states where you can ride a motorcycle without a helmet even take your child on the back the same way. And its all legal. Delmar Benjamin was kind enough to take me for a flight in his fabulous Buecker Younmeister ( sp?) but we left the chutes in the car so did not do any acro much less spins down low. Course Delmar was kind of a novice and maybe too cautious. I wouldnt do a low atltude spin with Patty Wagstaff, but thats my uniformed opinon based not just on common sense but also 40 years of losing friends many of them in low altitude acro.

[WLIU]

The IAC Primary competition flight program includes a spin. We have relatively new aerobatic competitors doing them flying with a safety pilot in the other seat. We do not see issues.

We see mostly our Primary competitors mostly flying in Decathlons but there are original Great Lakes with round engines doing contests in Texas I am told. The Decathlon is the modern equivalent to the Great Lakes, although the Great Lakes has more inverted and snap-roll capability.

There are 3 aerobatic contests in Colorado at high altitude airports this season. They just flew the High Plains Hypoxia Fest in Sterling. Earlier they flew the Ben Lowell contest at Ft Morgan. Coming up is the Clyde Cable Rocky Mountain contest at Lamar. You will see Primary level pilots spinning below 4000' AGL (10,000' MSL) at these contests.

Spinning a 1500 or 2000 lb airplane is nothing like spinning an 8,000 or 10,000lb airplane.

Best of luck,

Wes

[DRGT]

... in a Great Lakes Biplane, ... While in the left turn we turned steeply to bring it around and held the nose up a bit.

I have never flown this airplane and I don't know its stall/spin characteristics. Further, I don't know any specifics about your flight - e.g. cg location, total weight, etc. My first question - what do you mean you held the nose up a bit? With the elevator or rudder? I assume you were slipping (intentionally?), just before the right wing stalled. At this point, I would really like to know how you positioned the controls. It is obvious the airplane began to skid and spin. My opinion is a good instructor would provide a thorough debrief which would include a step by step of what happened and why.
I have no opinion on the correct altitude to do spins in a Great Lakes - I don't know the airplane or instructor. I would prefer a little more altitude myself.

DRGT

[vaflier]

Bill, I apreciate your concern for my safety but we all have different levels of acceptable risk. For me this experience was well within my personal tolerance. As for spinning a P-51, well it sounds like a lot of fun but I strongly doubt I will ever have that chance. I will plainly state that this experience has stuck with me all these years and has made me a better pilot as a result. I am safer because of the lesson learned. Thats a win in my book.

[Frank Giger]

I dunno about the Great Plains biplane, but I did my spin training in a 7AC Champ at 3,500 feet AGL and it just wasn't a problem. No, we didn't have chutes, but a Champ is such a docile aircraft that the hard part was getting a spin to stick, and immediately came out of it.

Now, then, I was pilot undergoing supplemental training that already knew the aircraft well, not a primary student. And my instructor knew me and the aircraft as well. That makes a huge difference.

When I learned aileron rolls in a Decathalon, it was a different story. First time in type with a new instructor, and we were at 5,000 AGL and chutes.

And yes, I suck at aerobatics - don't like them. They're valuable, as it teaches precision flying, but it's not fun for me.

[rwanttaja]

I've told this story multiple times...on my very first flight after getting my Private, carrying my very first passenger, I got into an accidental spin. I pulled into a tight left turn, then WHAMO the old Citabria was on its back, whirling into a right-hand spin. My instructor, a month or two earlier, had given me an hour's worth of acro dual, including spin entries and recoveries (no chutes...we'd found that one had opened in the storage locker). However, I attribute my survival not to the training, but to the Citabria's normally spin-adverse nature and the fact that I had about 2,000 feet of air beneath me. How I kept from a secondary stall during the pull-up, I just don't know. I really hauled back, watching the North Dakota prairie rotate below.

What I *wish* could be taught/experienced is how such events take one unaware. I'd been flying that airplane for nearly my entire Private course. It was as familiar as an old chipped bicuspid. But 70 hours in the CAP 7ECA hadn't prepared me for the way it turned in a whirling hell-demon at the drop of a hat. I had no idea it would do that to me. Gradual deceleration then rudder at the break just doesn't show it.....

Ron Wanttaja

[Bill Greenwood]

"We do not see issues". I have never met a pilot who first thing in the morning said, "I think I wiil go out and kill myself today, " and by the way take someone else with me. Nor an expert skier who said "lets go find an avalanche to die in today." But it happens, over and over and over, and no one sees any issues.
And I dont need to go to a contest to see someone taking a risk in an airplane. I can see dozens of motorcycle riders here every day without helmets and sometimes they get away with it.
Ive been to crash sites where airplanes spun in from low alt aerobatics. Ive seen the wreckage, and even more so had to report to the families and watch hurt that never goes away. And while heavy planes may hit hard, no plane is immune to crashing and fatally, even a Cub or Champ.
There are risk that people take knowigly. If you downhill ski race at 80 mph you are going to have falls and get hurt almost surely. But that is different than doing something in a way that is more dangerous than necessary to learn.
Believe it or not, I have flown a Citabria and Decathlon and done so at high alt airports in Colorado. Our club owned one.

[Bill Berson]

Yeah, my first accidental spin is burned in my memory. I was demonstrating slow flight and stalls in my Chief to a female coworker (who was also a new pilot) and suddenly it was in a spin. Fortunately I had started the stall practice at 3500 agl.
I looked at her and she had no clue. Then I looked at the control yoke and my hand was pulling the yoke hard into my chest.
After 5 seconds I decided to release the back pressure. Previously, I had purposely hired a spin qualified instructor and did two spin recoveries. My regular instructor in the Cessna 150 never did any spins. But I knew the Chief was spin prone so I got spin instruction even though not required by FAA.

[WLIU]

The good news is that Ron and Bill are both examples that demonstrate that spins below 10,000' AGL are not instant death. An accidental spin at 2000' is recoverable even with a severely surprised pilot. Our GA airplanes are designed and tested to quickly recover from spins.

It is important to replace fear with training and knowledge. Fear and ignorance is not an effective safety program. Training and knowledge is. Having an hour of spins and acro greatly reduces the length of confusion time before the pilot recognizes the situation and starts recovery control inputs. You may not realize this at the time, and credit luck, but an individual with no familiarity with a situation will generally take much longer to react appropriately and may never figure out what they are seeing and experiencing.

I will note that every GA aircraft has been spun by factory test pilots. If your factory airplane does not have an "Intentional Spins Prohibited" placard, it will recover from a typical spin with a little help from the pilot. But that pilot will do better if not handicapped with fear and ignorance.

Which is to say that demonstration of spins should be in the Private Pilot training.

Best of luck,

Wes

[martymayes]

I got spin instruction even though not required by FAA.

exactly! Anyone is free to seek out training beyond FAA minimum requirements. That applies to any class, category or segment of training. Doesn't mean everyone should have to do it.

As far as putting on a parachute in something like a Chief and expecting to be able to exit a spinning airplane and deploying the chute, well, good luck with that.

[Bob Dingley]

Great discussion. So far, no knows WHY the outside wing of an airplane in a coordinated turn will drop at the stall. (I am told in another thread that there is NO SUCH THING AS A STALL) My post, #28 in the LOC thread describes the conditions for the maneuver. Again: Enter a shallow turn in coordinated flight ailerons neutral. Power off. Maintain altitude with elevator. As airspeed decreases to stall plus about 10 KTS, full aft stick. Accelerated stall. My CFI showed this to me in a J-3. His background was as a contract instructor in WW2. (Embry Riddle in Stearmans)

At the stall, the J-3 rolled out of the turn and would have gone into a bank in the opposite direction if not stopped with bottom rudder. He briefed me to what would happen and I was ready with the rudder and stopped her wings wings level. Normal stall recovery.

Since then, I practiced this maneuver in my Champ, Luscombe, Beech, some Cessnas and a few sailplanes. All the same, and not a scary maneuver at all.

Why does the outside wing drop first?

Years ago, I landed at a small field north of Columbus, Ga. Met an old gent who told me that he ran a CPT program during WW2 up in NC. Had 75 Luscombe 8D's. Accident rate was high, almost all were when turning base to final. I had an 8A then and looked at the POH at the diagram of the instrument panel. No T&B. Not even an inclinometer.

Bob

[Bob Dingley]

After thought: I have observed that those that are the sloppiest making coordinated turns are Helo pilots. Makes you want to scream when they let the ball (or the yarn on the WS) go way off in a skidding turn.

[raytoews]

I agree, excellent discussion on a subject covered many times, but like recurrent training is good to re hash. What I notice is how often the lawyers insurance companies and govt are invoked in discussion. None of these entities have anything to do with the creation of lift thrust or drag.
Jim Rest taught me to fly and Orville Wright taught him and as long as lift works I will fly.

[Bill Berson]

After thought: I have observed that those that are the sloppiest making coordinated turns are Helo pilots. Makes you want to scream when they let the ball (or the yarn on the WS) go way off in a skidding turn.
Helicopter pilots don't use the pedals for turns in cruise.

[martymayes]

After thought: I have observed that those that are the sloppiest making coordinated turns are Helo pilots. Makes you want to scream when they let the ball (or the yarn on the WS) go way off in a skidding turn.

While flying helo? Or fixed wing?

[Bob Dingley]

Sorry bill, They do power changes in the traffic pattern. Marty, helo drivers mostly fly helos. They pick up more discipline when in airplanes because they are harder to fly.

Bob

[vaflier]

I have never flown this airplane and I don't know its stall/spin characteristics. Further, I don't know any specifics about your flight - e.g. cg location, total weight, etc. My first question - what do you mean you held the nose up a bit? With the elevator or rudder? I assume you were slipping (intentionally?), just before the right wing stalled. At this point, I would really like to know how you positioned the controls. It is obvious the airplane began to skid and spin. My opinion is a good instructor would provide a thorough debrief which would include a step by step of what happened and why.
I have no opinion on the correct altitude to do spins in a Great Lakes - I don't know the airplane or instructor. I would prefer a little more altitude myself.

DRGT
We held the nose up to allow speed to decay instead of dropping into the turn and increasing airspeed. The intent was to show me the classic base to final stall when you overshoot and try to horse it around. As it has been a long time ago I cannot say I remember every detail at this point but I absolutely fly that turn more precisely and with greater care. It really left an impression. Low and slow and push it will cause you to wind up dead. As far as control position is converned I recall being set up with lots of left aileron , not enough left rudder and a fair amount of up elevator. I knew we would stall but expected it to roll left into the turn and spin, instead it snapped over to the right pretty violently and instantly spun. Caught me by surprise.

[asport22]

I would suggest you all watch the video "Turn Smart" by ag and airshow pilot Wayne Handley. www.youtube.com/watch?v=2pGuoc11lxY Turns out the reason one wing or the other stalls first in a turn is KNOWN, and Wayne demonstrates in his video. I usually stay out of these opinion/myth discussions because most people have their minds made up and don't want to be confused by the facts. However, in this case, it involves the lack of understanding of the need to KEEP THE BALL IN THE CENTER. Every flight instructor I've flown with (and the Airplane Flying Handbook) say it is because the airplane is more efficient when coordinated (which is true), but the real reason is because when ball is not centered, the airplane will roll when it is stalled - and often roll briskly (guess how you do a snap roll). If the ball is to the left, the airplane will roll right. If the ball is to the right, the airplane will roll left. Ball centered, the nose will drop essentially straight ahead (unless the airplane has rigging issues - but usually those cause minor wing drops compared to the ball being out of the middle).

Lack of understanding of the need to keep the ball centered is a major component of loss of control accidents. Obviously pilots aren't being taught correctly - and even more amazing to me, the ball isn't even a required instrument for VFR flight (which I guess indicates the FAA doesn't understand it's importance either). KEEP THE BALL IN THE CENTER!!!!

Warren

[DRGT]

Obviously pilots aren't being taught correctly - and even more amazing to me, the ball isn't even a required instrument for VFR flight (which I guess indicates the FAA doesn't understand it's importance either). KEEP THE BALL IN THE CENTER!!!!

Warren
I agree with the first part about pilots lacking adequate training. However, I agree with the FAA's position on slip/skid indicator. A slip/skid indicator is a required instrument for IFR flight. Further, I think Chapter 3 of the Airplane Flying Handbook is pretty good. (Chapter 4 is another story) It specifies how pilots should be trained - i.e. how to "feel" and see what the airplane is doing. The FAA handbook rightly emphasize that pilots need to finely tune these skills. As stated in this thread and the LOC thread, the instrument panel is not needed during VFR flight. Remember there is lag in what the instruments indicate. Pilots should know what is happening before looking at the instruments. Adequate thraining can correct this and prevent most LOC accidents.

[WLIU]

You don't need a ball for VFR flight. If you pay attention, your butt will tell you everything you need to know.

Best of luck,

Wes

[rwanttaja]

You don't need a ball for VFR flight.

Well, for taildraggers.....

[Comment deleted]

[second comment deleted]

[Third, even nastier comment deleted]

Ron "Biting my tongue" Wanttaja

[asport22]

I've been hearing that "calibrated butt" line as long as I've been flying, and while I do believe that skilled pilots in VFR can fly coordinated without looking at the ball, I freely admit that I cannot. I also highly suspect, but have not yet proven, that it's not really the "butt" that the skilled pilots are using as a sensor. If it was the butt, no ball would be needed for IFR, either. (And before you argue with that, think carefully about what both the butt and ball are sensing. Hint - it's exactly the same thing.) I believe skilled pilots actually sense skids and slips visually, by noticing subtle differences in how the nose moves as the airplane rolls into a turn, and maybe they can even visually detect the angular misalignment of the longitudinal axis of the aircraft with the horizon after the bank is established. I wanted to test that with my instrument instructor by having her close her eyes and see if she could reliably detect whether the aircraft was skidding or slipping, but we never got around to it.

So, I still believe many base-to-final and departure spins would be prevented if pilots would be more careful about keeping the ball centered. Watch the video.

Warren

[Ron Blum]

I hear that there is a great Oshkosh forum presentation on Thursday, 2:30PM, Forum stage 6. It is an open forum; come voice your opinion (respectfully).

Yes, the aircraft will "typically" roll (after) a stall to the side opposite the ball. There is more wing drag on that side of the airplane at that moment.

In the case of the turning stall (and if coordinated), the airplane will roll toward the "up" wing side (opposite the original direction of turn). Why? … because there is some down aileron to keep the airplane in the turn (it's fighting the lateral stability of the airplane … which wants to level the wings).
..
If you come to the forum, you'll learn that the vast majority of fatal stall/spin/spiral accidents are on departure (takeoff/go-around … not base to final), in day VMC conditions, and with light winds.

Ron "30+ years in Flight Test, Chief Engineer and Aerodynamicist … and still learning" Blum

[lnuss]

I believe skilled pilots actually sense skids and slips visually, by noticing subtle differences in how the nose moves as the airplane rolls into a turn, and maybe they can even visually detect the angular misalignment of the longitudinal axis of the aircraft with the horizon after the bank is established.
Then how come I can be in the back seat of a Cub (so I can't even see the panel), looking (literally) in ANY direction, including over my shoulder to spot traffic, and still sense it -- can even do it with my eyes closed? It really IS the butt -- I really DO know what part of my body is talking to me.

Don't get me wrong, visual is important to many things in VFR flight, especially checking slight deviations from what you want in pitch and roll. and learning to see those differences when looking in directions other than straight ahead, but you DO have to be relaxed in the seat, not tense, to feel that slip/skid. So have your CFI fly, gently adding rudder one way (with wings level), then the other, while you sit very relaxed in your seat, with hands and feet off the controls. This is just to see if you can detect something.

[WLIU]

Once upon a time I flew with an elderly CFI to learn how to fly tailwheel airplanes. Sabby's big message was to relax into the seat and feel the airplane. He told jokes over the intercom and would whack you on the back of the head with a sectional in a tandem airplane. His point was that VFR flying is much more like surfing than a video game. Feel the wind and the airplane. Too many pilots fly around crooked and wonder why their IAS is below book speeds (excess drag) and why the airplane jerks around when they land (sidewards drift). Your airplane will talk to you if you listen. But you have to relax and listen.

And in the Pitts, in level flight in the traffic pattern, you absolutely can not see anything in front of you. Your eyes are not keeping you straight and coordinated, your butt is. And it does not take very long to become "expert" if you try. Cover up everything but the airspeed indicator and the altimeter, relax into the seat and listen to the airplane.

Best of luck,

Wes

[jstro]

I also highly suspect, but have not yet proven, that it's not really the "butt" that the skilled pilots are using as a sensor. If it was the butt, no ball would be needed for IFR, either. (And before you argue with that, think carefully about what both the butt and ball are sensing. Hint - it's exactly the same thing.) I believe skilled pilots actually sense skids and slips visually, by noticing subtle differences in how the nose moves as the airplane rolls into a turn

I do think the highly skilled pilots feel the lack of coordination, and certainly the flight instructors I've worked with the most sensed it this way exclusively. I'm not going to say I'm highly skilled, but it's what I try to do. If I'm doing a turn or roll, maybe while flying an acro sequence, I'm looking out the window at my wing tip, at a cloud or at a ground reference, so I need to feel the coordination instead of looking at the ball. But the ground referencing isn't what's tipping me off. In fact, it's a bad thing to use the ground as a reference for coordinated turns when you've got strong winds, it's going to mess you up. I remember an instructor catching me doing that on a windy day.

[enginesrus]

In my beginning flying days I think I remember climbing to 5000 or about 4500 agl to do spins. I spent a whole hour plus session one time with one of my old instructors just spinning till he got too queasy from it. I haven't been pilot in command for over 20 years now, just some good times back then. All my spins in a good old cessna 150, its a battle to keep everything in the correct condition spinning in them and coming out of the spin not over speeding and or pulling too many G's. I think there are too many pilots that shouldn't be flying if unusual attitudes are scary for them.

[raytoews]

We have had fatal accidents in Canada in the last few weeks. They all look like stall spin accidents. WTF.

[Frank Giger]

You don't need a ball for VFR flight. If you pay attention, your butt will tell you everything you need to know.

Best of luck,

Wes

This is dependent on the aircraft as much as it is the pilot.

In the Champ, any slip at all was easy to feel...and if someone was behind me, doubly so.

In my Nieuport, it can be subtle. With the flying tail (no vertical stab), the infamous "sneaky slip" is easy to get into. She just naturally tends to yaw if one isn't really on top of it. Worse, it's not much.

So here's the setup for danger if one doesn't check the ball from time to time in an aircraft with a flying rudder:

Rudder comes off center a little (in the case of VW driven aircraft, to the left). The plane will slowly, bit by bit, begin to roll to the left. It's not sudden, it's very gradual. The pilot arrests this roll with aileron input (if he's not aware of the quirk) to the right.

Again, it's subtle, but it can build from there, and pretty soon the pilot is cross-controlled, thinking he's in something other than a slip.

Dick Starks of the KC Dawn Patrol (who is guilty of many a 7/8ths scale Nieuport 11 being built) sums it up this way:


A bunch of us were sitting around the table in the hangar a few days ago solving the problems of the world and, I might add, doing a heck of a job when the subjects of aircraft instruments and the latest Victoria's Secret Catalog came up . The question was asked as to what we think is the most important instrument in our Nieuport panels and the unanimous choice was..

The skid and slip ball.

Why? We hear you ask... It doesn't even have any gears of actual moving parts.. It's simple... The Nieuport (except for the 24 and it's a tiny little thing.) DOES NOT HAVE A BUILT-IN VERTICAL FIN FOR INHERENT DIRECTIONAL STABILITY. All its got is a full flying rudder which,since it's not fixed and just kinda floats in place, gives you no built-in directional stability at all. What do that mean? It means that if you relax pressure on the rudder bar while flying, the plane can go into a skid or slip without you knowing it. In fact, torque will automagically do it for you if you're not on the bar and ON THE BALL (so to speak.) We all swear that we've been able to hear that "click" when we really get outta whack in a turn and bury the ball on one side or the other of the tube. If you don't pay CONSTANT ATTENTION to that little booger... It'll quickly and without warning, sneak up and bite you right in the ass.

Mark Pierce does a heck of a demo in his air show act showing how the Nieuport can almost be flown sideways with very little rudder input... Or, another way of putting it would be to say.. With very little pilot attention to the ball. We call it the "Pierce Horizontal Knife Edge." While he's doing it on purpose, a little inattention on your part can have it happen to you NOT ON PURPOSE and at a low altitude at low air speed... You ain't gonna like the outcome!! What happens is that as the plane gets more and more screwed up, you start to feed in aileron to try and keep things "feeling right." Then you suddenly end up with a cross-control stall/spin and THAT'S A REAL BAD THING. (I've done this I might add, in my C-120, on purpose, with my instructor on board, at altitude, and when it finally happens, it's a real shorts-staining shocker.)

There's a whole flock of Nieuports getting built out there and a lot of them are going to be flying soon. We can't emphasize enough the importance of that skid/slip ball.

SO....PAY CLOSE ATTENTION TO THAT MOMMA...
IT'S IMPORTANT.
(Or, as Dick Lemons likes to say,)
"You fly with one eye on the ball,
and the other eye on the ball. "
(Or, In other words)
Watch The Damn Ball!!!
(or, as my sainted flight instructor used to yell in my ear.."
"STEP ON THE BALL!!!. STEP ON THE BALL!!!"
(Thus endeth the lesson.)
Now... There is something you can do to help

All of us now have a small length of bungee going from a small sailboat jam cleat attached at the bottom of station 117 on the starboard side going to the extreme starboard end of the rudder bar. After getting in the air, we reach down and adjust the tension of the bungee to attempt to hold the rudder in an approximation of "feet off" so we can fly without the constant attention needed to the ball. It works great BUT any change in rpm will make you have to change the tension on the bungee.

Still... all in all... it's a great help.

(emphasis mine)

http://www.dawnpatrol.org/questions.htm

Now, then, I don't have a rudder bar, but independent pedals, so the bungee trim fix won't work for me. I just have to scan the ball....and yes, I've experienced exactly what Mr. Starks is writing about - but I was forewarned thanks to him and didn't proceed to the spin/stall.

[Bill Greenwood]

I took some acro lessons for legendary pilot Duane Cole many years ago. If you have seen his engine out gliding descent while inverted and doing acro its impressive and he didnt rely on a screaming annoucer nor a whining cavitating prop nor a jet engine blast to make his act. I remember one moment vividly, I was sitting in the rear seat of a Decathlon and flying the landing approach and I asked Duane to lean over to the right so I could see past his shoulder to see the ball on the instrument panel. Duane was a man of strong opinions and sometime strong expressions of those opinions and he left no doubt that I should be able to feel what the plane was doing without having to see the ball. "You dont need that thing, its just something someone invented so they could sell you something." I didnt dispute this but I did lift myself up from the seat enough so I could take a glance at the ball and was reassured to find it was in the middle, and I didnt worry about it anymore. He probably wasnt too good with a smart phone or an ipad, but he could fly.

[Frank Giger]

Well, Bill, I won't disagree, especially when landing.

While I put little flying videos out, the real reason for filming is because I never look at the instruments when taking off or landing, and it's a great troubleshooting tool.

Oddly enough, even though I tend to cruise around a bit uncoordinated, on final that ball just seems to find it's way to the center and stick there the whole way down.

[Ron Blum]

Frank, are you part of the KC Dawn Patrol? If so, when do y’all normally get together to fly? I’ll find time to come up and see the antics. Thanks, (just an average) Ron

[Frank Giger]

Nope, they're just outside of Kansas City, MO, and I'm down here in Alabama.

However, I had a chance to hang out at their aerodrome for a full day, and then for a couple more at the Gardner, KS, airshow (which is now defunct).

I used the very clever method of looking up Dick Starks in the phone book and calling him, asking if they were going to be out at their airfield that weekend. They had planned on it anyway, and I got the royal treatment....hot dogs, coffee, education, flying chase plane to Nieuports in a Champ, etc.

The one of their group you really want to talk to (now that Tom has passed), is Sharon Starks. Not only is she an expert builder, but an Ace pilot, and able to speak in small sentences to explain stuff.

[Ron Blum]

The one of their group you really want to talk to ... and able to speak in small sentences to explain stuff.
Awesome. Thanks!

I’ve heard about it the lack of directional stability in WWI airplanes. Dick Curtis has a Fokker DR-1 here in Wichita, and he says that it’s happy flying sideways. This might be what took many of our early fighter pilots. It would be tempting to get “guns on” by yawing the nose on target.

[Bob Dingley]

This is a great topic. So far, no one has answered my question in #24. "In a shallow COORDINATED TURN, slowing to an accelerated stall, why does the outside wing drop?"
This was shown to me about hour four or five by my instructor, Clyde Davis. Clyde spent WW2 teaching primary to Fleet Air Arm pilots in Stearmans somewhere in Georgia. The maneuver likely was brought over from the UK. Clyde could be a nag if an aileron was sloppily displaced during the maneuver. It works the same in a PA-22 with interconnected controls BTW.

In post #31, we were offered a very good video by Wayne Hadley on the evils of miss using aileron in turns. This was apples and oranges. Not the same thing. It is my hope that someone smarter than me would answer the question: why does the aircraft roll out of the turning stall, banked in the opposite direction?

Bob
EAA 29005
ATP
FAA Master Pilot

[rwanttaja]

This is a great topic. So far, no one has answered my question in #24. "In a shallow COORDINATED TURN, slowing to an accelerated stall, why does the outside wing drop?"
My guess: Due to the dihedral of the wing, the lift vector of the outside wing is at a less advantageous angle to the gravity vector. Thus a very slight amount of additional aileron is needed, and thus it stalls first.

Ron "Space Engineer, not Aero Engineer" Wanttaja

[Ron Blum]

This is a great topic. So far, no one has answered my question in #24. "In a shallow COORDINATED TURN, slowing to an accelerated stall, why does the outside wing drop?" ... It is my hope that someone smarter than me would answer the question: why does the aircraft roll out of the turning stall, banked in the opposite direction?

Bob: I tried to answer your question in paragraph 3 of my reply #36. In a turn there has to be some (although slight) down aileron on the up wing side (and/or up aileron on the down wing side), otherwise (if the controls were let go) the airplane would have a tendency to return to wings level flight ... due to the inherent lateral stability of the airplane. As a result, the up wing stalls first. In addition to this wing now having less lift than the down wing (which is still flying), it also has more drag because it is stalled. Asymmetrical lift (now greater on the down wing) and asymmetric drag (higher on the up wing) will turn the airplane to the direction opposite the original turning direction.

Many people think that a whole (right or left) wing is either lifting or not lifting instantly. This is not true. The stalled or separated portion of the wing will progressively flow/move with changes in angle of attack (both aircraft and local). Even a completely stalled wing is producing (roughly) 50% CL-max.

BTW, yes, I am a degreed Aero/Astro Engineer with 30+ years in the business, but that doesn’t make me smarter than you or anyone else. I am still learning. Please keep asking great questions. I love the challenge.

Ron “solutions@blueontop.com” Blum

[Bob Dingley]

Ron and Ron, thank you for taking the time to set me straight. Dihedral. Of course. As for the separation moving span wise on the wing, years ago, in a SG 1-26 I was wrapped up in a tight turn, coreing a thermal at stall plus 2 or 3. I glanced back at the wing trailing edge at the fuselage juncture. There was a triangular area that was obviously, visually turbulant. The skin was vibrating. I eased off back pressure and the turbulant area grew smaller. increased back pressure and it got bigger. Looks like it was time to re- skin the wing.

Bob

[Ron Blum]

Ron and Ron, thank you. Dihedral. Of course.

There is a really good book by Hubert C. ("Skip") Smith entitled, "Illustrated Guide to Aerodynamics". I highly recommend it … lots of little yarn tufts so one can easily see what is going on. Obviously the yarn destroys any prayer of laminar flow :)

I believe legally (but don't quote me … and I'll deny it) one can tuft an airplane without going into "Experimental" category. As an FAA Flight Analyst DER, you would think that I would know that answer. Guess I'm used to being in the "X" category all the time.

You're welcome,
Ron "we all learned something today" Blum

[raytoews]

Aileron should not be a factor in a stabilized turn. When banking the airplane I teach ,look, kick and turn, then neutralize, the airplane should continue at this bank angle (turbulence not withstanding) until you reverse the bank angle.

[Bob Dingley]

Somewhat off topic. A late friend instructed in B-24 and B-29's in the early 40's (until he was shipped to Tinian). He told me that part of the B-29 check out included stalls in a 60 degree bank. Of course, the complete crew was aboard.

[Floatsflyer]

Somewhat off topic. A late friend instructed in B-24 and B-29's in the early 40's (until he was shipped to Tinian). He told me that part of the B-29 check out included stalls in a 60 degree bank. Of course, the complete crew was aboard.

Practicing for steep turn to the left after simulating atomic bomb drop???

[Ron Blum]

Aileron should not be a factor in a stabilized turn. When banking the airplane I teach ,look, kick and turn, then neutralize, the airplane should continue at this bank angle (turbulence not withstanding) until you reverse the bank angle.

Unless one is flying an airplane with neutral or negative lateral stability, there will be a little down aileron on the up wing (and up aileron on the down wing). This may be masked by aileron system friction. We're not talking large amounts like 2-3 degrees, but there will be some. All certificated airplanes must have positive lateral stability.