Among all the great lessons of the last few weeks, one should be abundantly clear; we humans eagerly embrace and hold passionately to half-truths and misinformation, and we love to be “right.” And as a species, we tend 
toward self-surety and obstinate, over-confidence – the dreaded “know it all!” This is a genetic, evolutionary adaptation that makes us fast to react and adapt – but humans are consequently weak on self-doubt, nuance, and verification. This tendency to act assertively on partial information and heuristics has allowed us as a species to conquer the globe, adapting and living from the arctic to the equator. But we have seen this tendency in politics, fueled by social media, can also make us all passionate enemies and cause great harm.
Unfortunately, in flying if we do not curb half-truths and haste and carefully verify our information, it can make us dead (Darwin award?) Hope and intuition do not work well with the aerodynamic of control, this game requires science. Gravity works all day, all night, all year long.
Misinformation (and associated mishandling of the controls) is a leading cause of Loss of Control-Inflight. It is essential for pilots and educators to foster and retain a flexible, self-questioning attitude. We must always be ready to check and refine our closely held theories and techniques, continually improving and learning. Misinformation can come from the “internet buffet of YouTube misinformation” but many errors and misconceptions are even deeper than that – built into our human operating system – 200K years of walking not flying.
It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so. – Mark Twain
As educators, it is our critical professional responsibility to study, verify and transmit only true facts regarding aerodynamics and control. We must dig deep into our learner’s understanding (questions/discussion/performance) and root out deeply embedded misinformation; we all drive cars and have embedded two-dimensional habits. Our human “naive rendition” of what makes planes fly and turn IS WRONG! Daily driving habits need to be identified and isolated from our flying skills. Safe flying requires different skills and continuous education – not intuition.
Many SAFE presenters have repeatedly reported from public presentations seeing the pervasive misunderstanding of turning flight among pilots and even CFIs. Usually, of attendees polled, >70% believe the rudder or ailerons create and sustain a turn. And like all humans, they are passionately committed to their misinformation. I was tracking a FaceBook post on this subject, where the poster was very gently trying to convince misguided pilots and CFIs that the elevator really controls the turn. Many pilots have never transitioned fully from the 2-dimensional world of driving and misunderstand the basic turn; the aileron application supplies the desired bank angle and rudder cancels the yaw the elevator is supplying the force that creates the turn.
A great tool to illustrate the forces in a turn is the Bold Method CFI java tool you can load and run on your tablet. This simple demonstration should precede the first introduction to turning flight (or we are reinforcing an error!) Rich Stowell’s excellent presentation on “Learn To Turn” is FREE in the SAFE public resource center and covers this topic thoroughly.
Educators have to irradicate misinformation and help a new learner grasp the true forces at work in flight if we are to make safer pilots. Regarding long-time pilots laboring under misconceptions, good luck with changing those entrenched minds, we all know that is harder than building skyscrapers in our current climate of “I’m right/your wrong (and stupid)” Fly safe out there (and I recommend some self-doubt and humility in everything!) Have fun.
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Spot on David. I see you have been following me around and taking down my lectures on aerodynamics, lift, control, and loss-of-control. 😉
The best way I know to learn more is to watch professionals like you! Keep up the great work.
Please.to all reading this section, be advised that I am NOT the poster who thought it was lift that makes an airplane turn.
Dudley Henriques
I don’t believe the elevator is supplying the force that creates the turn. Sure you can roll into a steep bank and pull back and increase the rate of turn. But what are the consequences. I think it could be exactly what happens with a base-to-final Loss of Control – a stall or stall/spin.
In a coordinated upright turn, maintaining altitude…rudders and ailerons are neutral and lift is equal on the wings. The only force is the elevator supplying the lift force to turn which you can vector analyze to obviously overcome weight but also provide a horizontal component to turn the plane. I often say to students “we lift through the turn” which is not technically accurate I guess if you were inverted or knife-edge (aerobatic pilots get on my case on this) but in our regular daily flying, the elevators are the active control in a turn. As bank increases, the G force increases exponentially and the stall also at the square root of the G force: 60 degree turn = 2 Gs = 41% increase in stall speed (1.414).
Not at all what I see. Except for the one spot the wings are neutral, anything more shallow or more steep will require active aileron control to maintain the bank position, which should be coordinated with rudder. Any aileron deflection also automatically means the lift is unequal. A small turn radius does also. When I demonstrate steep turns, I put the pitch at level, high, and low positions to demonstrate how that affects altitude. It doesn’t affect bank or rate of turn – if it does, it’s from incorrect technique on the control wheel inadvertently changing bank. Of course there’s active control on the elevator – most of the time it isn’t trimmed out. But 99% of the time, there’s activity (usually very subtle) on all of the controls. When pilots want to change the rate of turn, it should be done with a change in the bank with coordinated rudder. Trying to increase the rate of turn with elevator, possibly when overshooting final or doing a 180 turnback, can easily lead to LOC.
I would like to add a couple of points here. I think that both David St. George and Warren Webb’s posts show some misconceptions about how how airplanes fly and maneuver. In general they are both on the right track but somewhat in error as well. My post may be a bit nit-picky and pedantic but I feel it is important to be VERY clear when teaching. We should identify when we are saying something that glosses over some intermediate steps with the intent to get a point across quickly without overloading the student’s (learner? client?) ability to accept information and drown the key ideas in detail.
First, Warren is correct — the elevator does NOT provide the force needed to make a turn. Elevator deflection just changes the mean aerodynamic chord and AoA of the horizontal stabilizer. The small amount of force provided causes the elevator and hence the longitudinal axis of the airplane to seek a new equilibrium with the relative wind, at which point the horizontal stabilizer/elevator is no longer producing an unbalanced force that causes a change in pitch. In essence, pitch rotation due to change in elevator AoA stops.
However, and this is a BIG however, this new angle to the relative wind IS a change in AoA for the wing since it is also attached to the fuselage at a fixed angle of incidence. This new AoA causes a change in lift and hence a change in the lift vector. The aircraft begins to turn due to the increased (or decreased) lifting force generated by the wing, not the elevator or horizontal stab.
But one thing Warren did get wrong is that turning has nothing to do with the use of rudder or aileron. These just serve to allow us to change the direction of the lift vector of the wing and do not make the airplane turn at all.
One other slightly-pedantic point: a turn is ANY change in the flight path of the aircraft. A turn need not be a heading change. Pulling straight back on the stick will result in a loop (assuming sufficient pull and airspeed to complete the maneuver), which is just another turn. (And I have left off some detail here which I can add in for those who really want to get crazed with summing force vectors, the formula for coefficient of lift, and conversion of kinetic energy into potential energy, etc.) At this point, several things can happen depending on the angle the lift vector to the gravity force vector. (People! This is what makes airplanes so TOTALLY COOL TO FLY!)
Some of Warren’s comments show a human bias that comes from the fact that we are oriented primarily in two dimensions rather than three dimensions. As humans we are used to walking around on a more-or-less horizontal surface. We tend to think in terms that are “flat”, with maneuvering being in the horizontal plane because that is how we walk around on the surface of the Earth and have for millions of years. We are programmed that way from birth.
Now we get in an airplane which is really a three-dimensional machine but we carry our 2D bias with us. That is why I have to emphasize that a turn is ANY change in direction in ANY plane. Two things brought this concept home to me: flying formation and flying aerobatics. Both of these force the pilot to change her frame of reference. No longer is the surface of the earth the primary frame of reference. In the case of formation, the lead aircraft becomes the frame of reference and the wing pilots fly relative to that. In aerobatics your own aircraft becomes the frame of reference and everything then has to do with controlling forces and energy to keep the wing flying the way we need it to fly without any real regard for the surface of the Earth … other than taking care to ensure that our velocity vector never passes through the plane that is the surface of the Earth. (wink)
Now with all that preliminary and pedantic stuff out of the way, here are a couple of truisms that I teach my students about how airplanes fly.
1. Airplanes stall because the pilot is asking the wing (pulling on the stick/yoke to increase AoA) to produce more lift than it is capable of producing at the current airspeed. Stop pulling on the stick and the airplane will stop stalling. If you understand this one simple thing you will never lose control of your aircraft.
2. The fore/aft position of the stick/yoke is a really good indication of your AoA!
3. Stall speed has absolutely nothing to do with bank angle. Stall speed has everything to do with the lift and hence G loading we are asking the wing to produce. The whole stall-speed/bank-angle thing stems from a very specific case — constant altitude, constant airspeed, and constant turn rate — that comes from our 2-dimensional human bias. Don’t believe me? Watch a pilot do a roll. The aircraft achieves all 360 degrees of roll without ever stalling.
4. When something goes wrong, PUSH! Keep the AoA below critical so that you retain control of your aircraft. Sometimes this can be a real mental problem, especially when something has caused the forward view through the windscreen to become entirely brown. ALL pilots need to develop this reflex. The only way you will develop this reflex is to practice it. This means you will have to stall your airplane over and over while maneuvering until this reflex becomes burned into your brain as “muscle memory”. By the way, developing this reflex is much easier in an aerobatic airplane than it is in the average trainer. (You should be flying at least a C150 Aerobat when teaching stalls and upsets to your students/learners/clients. You don’t have one? How about a Citabria? You don’t fly tailwheel airplanes? Uh …)
5. We don’t need spin training. If you need to know spin recovery your screw-up has already progressed WAY too far. You really need to have that upset-recovery reflex. So while we do need more training over and above just stall avoidance, we don’t need to go all the way to spinning the aircraft. (There you go! Both sides of the spin-training/no-spin-training argument are wrong! Yeah, I tend to be a lightning rod and an equal-opportunity offender.)
6. Does anyone else think that changing the name from “student” to “learner” or “client” is as stupid as I do? Changing the word does not change what the thing is doing. Anyway …
One thing has changed substantially over the 50+ years I have been flying: the training and experience of CFIs. When I started flying in the 1960s the bulk of CFIs had military training. Today that is not true. So I point to military pilot training as a point of reference. All military pilots are trained in formation flying, aerobatics, upset recovery, and instruments as part of their primary training. The military works hard to break its student pilots of their 2D mindset early on in training. Maybe those of us teaching flying in the civil world should do the same.
Enough. Sorry for the over-long missive. This is a hot-button for me and I can get a bit long-winded. Hopefully you can take something useful away from this rather long, rambling reply.
Back to you David.
This * needs* to be a “hot-button issue! It is the heart of most LOC-I accidents. My concern is if it takes too many words to explain perfectly the concept, all benefit is lost for average pilot. (And they are never going to get “deep learning” of military training, but need to “Learn to Turn”)
The >50% who think the rudder turns the plane need *broad brush* help not excessive nuance. Basic “big picture” elevator creates the increased wing lift (AOA), that lift is equal on wings in a constant rate, constant altitude turn (or it would be still rolling!) Rudder and aileron are basically neutral and elevator (AOA) is supplying the force. G is greater, stall (exponentially) higher; pull too hard (greater AOA) and it stalls straight away from elevator force applied (right side up or upside down). Uncoordinated (too common – pilots holding inappropriate aileron or rudder pressure and it spins!) Agree with 1-6 but KISS, train it often!
I don’t think I said that turning is done with the rudder or aileron. I was pointing out that 99% of the time, turns are not done with rudder and aileron neutral as David indicated. The airplane will roll out of a shallow banked turn or continue to bank further in a steep banked turn unless the ailerons are deflected as needed to hold the wing in a steady bank. Rudder should be used for coordination so it will be deflected also. The biggest problem for me with this article is suggesting the elevator is the only force in a coordinated turn – will only lead to more LOC. And thank you for your ‘missive’ – very interesting.
Roll into 30 degree bank, add two rolls nose up trim and fold your arms (cross your legs). Your plane will happily turn till it runs out of fuel. (I demo this to every apprehensive student)
Hi Warren. I am afraid I have to agree with David that elevator *input* (not force – the elevator is not providing the force, the wing’s lift is) on this. The elevator/stabilizer changes the AoA of the wing, changing its lift. It is the vector sum of lift, thrust, drag, and gravity that provides the resultant force to cause the aircraft to accelerate, i.e. change direction.
OTOH, I do agree with you that there are small aileron and rudder inputs needed to keep the wing in equilibrium and not producing asymmetrical lift. Regardless, these inputs are very minor compared with the major one which is the lift vector of the wing making the airplane “turn”. Most of the time they can be ignored as David has commented.
If the airplane is trimmed for unaccelerated flight (direction and speed are constant) the only way to upset that equilibrium and cause the airplane to accelerate into a new and changing path is to change the AoA of the wing (move the elevator) or to increase power to increase thrust and change the airspeed. Again, the dominant effect comes from the elevator input.
No matter what we do there will always be interactions between the controls. Yaw (rudder) input excites yaw-roll coupling as well as creating lift from the fuselage due to changing the AoA of the fuselage. Both of these minor effects make some people think they can make the airplane turn using rudder. It sort-of works but it isn’t a big effect compared to using the lift vector from the wing. (If it didn’t work to some extent, aerobatic airplanes couldn’t fly knife-edge.) This just shows that there is one more airfoil on the aircraft.
It really boils down to what thing on the airplane can provide the greatest amount of force to change the aircraft’s flight path. #1 is the wing. What control changes the AoA and hence the lift from the wing? The elevator. Only gravity has an equivalent effect and its force is limited to the weight of the aircraft.
Warren, I invite you to come fly with me. I teach AoA awareness and LOC prevention. I show how the dreaded base-to-final-stall-spin scenario develops. It is interesting to see how a sequence of events leads an unsuspecting pilot into commanding her airplane into a snap-roll and is then surprised when the aircraft obliges. That is why reducing AoA in any LOC event is so critical, and needs to be a reflexive action.
And there is the key: train it often. Talking about it only begins the process of awareness, i.e. “Now I know what I don’t know.” This training needs to begin early, when the concepts of stall and stall recovery are being introduced, not 20-30 years down the road.
I bring up military training only as a point of awareness, hoping to trigger the thought, “Hmm, I wonder what they know that I don’t know?”
You know, we should be including this stuff in our flight reviews. (wink)
Yes, that is the “Extended Envelope Training” (I sent you?) Just basic turning stalls (in private ACS) properly demonstrated (and fully comprehended) are *big* eye opener (“I never knew that…”) Unfortunately, many new CFIs need this too (SAFE CFI-PRO)
My primary students work up to accelerated stalls out of bank angles exceeding 45 degrees. It is not aerobatic but boy does it get their attention.
As it should be! I love to demo turning stalls in a full slip (after coordinated turning stalls and w/ no power) Nothing happens – less reaction that straight ahead – stable! Shocks every student! “I thought ‘cross-control’ would spin?” Well, yes…in a ‘skid’ (or put in full power like a botched go-around) Eye-opener.
Yes. I left it out of my overly-long missive above but I also teach that, when near or at stalling, coordination is unimportant. What is important is to neutralize the aileron and maintain directional control with the rudder. No rotation, no chance to depart into an incipient spin. Reduce AoA, get back aileron control, then roll back upright.
👍 I’m with you on that. Just before COVID, flew w/Patty’s school. (Chief CFI Allan Moore is great – my usual ride burns Jet A – no rolls!). Great course. Patty also has a new aerobatics course w/ Sporty’s – maybe spark some growth?
What happens in a standard rate turn or a 60 degree bank turn?
Generally speaking (depending on how well rigged your plane might be) If you are less than 30 degrees bank in a standard trainer, it recovers to level flight due to dihedral (longitudinal stability) If it is over 30 degrees, it will roll slowly into a spiral (spiral instability). Both of these are good demonstrations for pilots…
Gruman (A/G) Tigers and aerobatic planes with less built-in stability (to enable maneuverability) roll into a spiral pretty quickly.
Thanks. That’s all I was saying.
I think we are all on the same page; terminology can easily obscure understanding (and I confess to being less than “precise”). All our (ancient) planes are a bit bent and Brian’s point is excellent; there is no “pure input” since every change requires some compensation on another axis!
Yes, I think we are all on the same page. Thank you Warren and David for a great discussion.
Brian – but from what you have said, you would disagree completely with David’s main point, right – “the elevator is supplying the force that creates the turn.” I’m into the issues with base to final also. And have done 180 turnbacks for around 30 years which is where it would be the most natural place to try to use the elevator in the wrong way to increase the rate of turn. The only input I make with the elevator then is to maintain best glide, never to increase the rate of turn which is what David’s statement seems to be saying is the proper use of the elevator.
Warren, I think that David was just a bit loose with the words he chose. If we pick enough nits then he was wrong to say that the elevator provides the force. But from the way we actually fly, we feel the elevator changing the AoA of the wing and we feel the acceleration change directly in response to the elevator input. So, if I squint just a bit, I can go with what he said. Certainly it is how it works from inside the cockpit, i.e. the elevator changes the AoA of the wing and therefore the G-loading on the aircraft. So, in short, yes, the elevator makes the airplane turn.
I too have successfully practiced and demonstrated the “impossible turn” back to the airport in several different aircraft. (It is actually about a 225 degree turn one way followed by a 45 degree turn the other.) There are many factors involved including starting altitude, starting airspeed, and wind velocity, all which can combine to produce a different result.
The “impossible turn” is very much an energy-based maneuver. The success is determined entirely by the starting energy state of the aircraft. The necessary energy can come from either potential energy (altitude), kinetic energy (speed), or the combination of the two. One of the interesting things here is that “best glide” is not necessarily the best speed for this maneuver. A higher speed (trading potential for kinetic) will allow an increase in turn rate and a reduction in turn radius. I need to look at the math but I think that Va may actually be better than Vg. We certainly don’t ever want to drop below Vg in this maneuver. I know that when I have done it I have flown the maneuver by “seat of the pants” and that I was very nose-low to allow maximum use of my lift vector (elevator input) to accomplish the course reversal rapidly.
One thing I take exception to is your characterization that there is a “wrong way” to use the elevator. The elevator serves only one purpose: to change the AoA of the wing. Obviously once I pull to the point where I have reached the critical AoA, I can pull no more or I will lose control of the aircraft. But in this maneuver I want to pull right to that point in order to generate maximum lift in order to change my flight path as quickly as I can. If you are doing the “impossible turn” and you don’t hear the stall warning for the entire maneuver, you are leaving some of your performance on the table. In fact, modulating your elevator input to keep right on the edge of the stall warning is going to get you pretty close to maximum performance and is the right thing to do.
If you need to tighten up the turn you must get the nose down so that you can use gravity to increase your airspeed in order to generate more lift to change your flight path. Lift varies by the square of airspeed. This is why we need to speed up to tighten up our turn safely.
(By the way, this is fighter-pilot stuff. They live and breathe energy management and cornering speeds. This is not something we GA pilots think about … until we need maximum turn performance in the “impossible turn”.)
Warren, thank you for bringing this up. You have focused my thinking on this maneuver and now I need to think about how to optimize it and then test my hypothesis in the airplane … at altitude of course, with the GPS recording the altitude loss and flight path.
That being said, I do agree with David. Elevator (input) makes the airplane turn. It is all about that critically-important lift vector, which is controlled directly by elevator input.
More speed increases lift, but more speed increases the radius of a turn too which could increase gliding distance. So many variables. Your tests should be interesting. I just did some turnbacks the other day. For me it’s more of a 210 degree turn. I generally roll out as soon as I can make a straight ground track toward the end of the runway to minimize gliding distance, i.e. a dogleg final. Maybe another time then we can all discuss how to handle that glide with a tailwind.
Are we trying to solve *every* aerodynamic problem here? Ever heard of the “frisbee turn?”
No to solve every problem and no to frisbee turn. If you want to explain ok. But I’ll regress to my original thought. Planting the idea to pull on the elevator to increase the rate of turn, which ‘elevator is supplying the force that creates the turn’ may be doing, is not a good thing.
Heh. Sorry. People say I think too much.
When someone in aviation says to me, “Well, everybody knows that,” I am immediately on my guard because I think it really means, “Nobody has a clue that…” It is at that point where I try to come up with a valid hypothesis and then go try it out in the airplane.
I have seen a lot of things fall into this category, things like, “You can’t safely turn back to the airport,” “Marvel Mystery Oil is good for your engine,” “A Nomex flight suit will protect you from fire,” “Flying over water is more dangerous than flying over land,” “Don’t run your engine over-square,” “The smallest radius turn is at minimum controllable airspeed,” “Running lean-of-peak will burn your valves,” etc. In aviation we need to stop accepting everything on authority and start thinking about the information itself. How many things are taught by CFIs purely because they were taught that by their CFIs, who were taught that by their CFIs … It is time to start asking the question, “Is it true,” and then taking steps to find the answer.
BTW, along these lines, AOPA Safety Foundation’s recent study of take-off performance chart accuracy was stellar work that EVERY CFI should be aware of and teach.
Agreed! Do you have a link for the SAI study on take-off performance (Barry Schiff did a VHS presentation on that subject years ago…)
It was the AOPA Air Safety Institute. The key point was, after take-off practice by several proficient pilots, aircraft in an excellent state of repair, and two common aircraft types, i.e. C182, and A36 Bonanza. They used take-off and landing performance data using Foreflight. The end result was nearly universal: actual take-off and landing performance was 30% greater than book numbers. I now teach that and then tell my clients to add another 10% for their own margin-of-error.
Here is the link to the video: https://www.youtube.com/watch?v=IMRafSuzkQ8
Thanks Brian!