He said it at 6:32: "If you don't pull back on the yoke, the airplane is not going to stall." I knew this, but I'm glad to hear someone else say it, and say it very clearly. -Old retired Cessna driver and RC intro flight instructor.
When turning from base to final, the airplane is normally not holding altitude, it's descending. If you need to increase your bank, it's ok so as long as you relax the backpressure and let the nose fall a little. This is why I like to come in high from downwind to base with less power, rather than dragging it in with power. If we keep it coordinated and increase the speed slightly while descending, we can bank steeper if necessary. Better to do that than standing on the bottom rudder and keeping the bank shallow instead. IMHO.
This makes so much sense. My first instructor told me don’t exceed 10 degrees while slow turning final. My second instructor said, after I kept over shooting final and being right of the centerline, bank more man. I said but I can’t go past about 10 degrees and he was like no you can, just don’t pull back on the stick. Didn’t quite understand why till now, thank you
So so good!!! It all goes back to exceeding the critical angle of attack. Too many people don't really understand the aerodynamics of flight, even after years of being a pilot. I don't think I did until I started working on my CFI rating. Thanks for taking the time to discuss and debunk the high bank angle= high stall speed myth! I really enjoy all your videos, but I really like the ones with Doug teaching and explaining. Keep the great videos coming. They are not only entertaining but they have a lot of educational value as well! Thanks Martin!
Thanks, Kevin! I’ve learned a lot from Doug over the years, and I’m so happy that I can share some of those things with the aviation community. - Martin
Great video. Couple of points that maybe the speaker will want to address next time: - I don't think teaching stall speed as a function of angle of bank is a disservice to private students. Most private students will forever remain private students, and some of them will go on to become private pilots who fly 20 hours a year for a couple of years until they quit forever. When you fly like that you can't realistically use any of this mathematically correct stuff. The most you can do is get it through your head that you can trust your airspeed indicator for the stall speed when you're level, and you can't trust it when you're banked. That's about it. It really doesn't make sense to try to make it any more complicated than that. You're level - watch for the bottom of the arc. You're banked - maintain whatever airspeed you're supposed to be at for this leg in the pattern and don't go any slower. Don't bank more than 30 degrees. You'll be fine. If one of a hundred students goes on to fly aerobatic jets - there will be enough time to get into more details. - regarding this point about pilots getting in trouble in the base to final turn because they are afraid to bank and they use uncoordinated rudder inputs. This has been repeated thousands of times, but I could never understand why. Has anyone ever seen a student who uses rudder to turn? Is it ever taught to turn with rudder during primary training? For every 99 private students who don't use the rudder at all in a turn, maybe there will be 1 who uses a little to much. I can't imagine why a student who flies around with zero rudder inputs would all of a sudden start pushing bottom rudder in that base to final turn at 500 AGL. Really not seeing it.
That's a good point but incorrect use of the rudder to increase the turn rate can inadvertently happen. For one example, think about the first lesson when the controls are demonstrated. The instructor applies rudder pressures to demonstrate how the airplane yaws left and right. That could result some day in the future with that pilot using the inside rudder to increase the turn rate - not likely if the training has been good and thorough, but still possible. And it did happen on one Prog Check at our flight school long ago. I was happy to see it mentioned that limiting banks to 30° can lead to the incorrect use of the rudder. But I was unhappy to see that that also didn't include the possible incorrect use of the elevator. When you roll into a bank, pulling on the control wheel will increase the turn rate similarly to using the inside rudder. But it costs airspeed, and I think of the two errors that can result from limiting banks, pulling on the control wheel is far more dangerous than pushing on the inside rudder because pulling on the control wheel is what causes the stall (and of course when there's also uncoordinated rudder, it will be a much more difficult, likely impossible, stall from which to recover due to the low altitude).
The concept of a Vector is one that most people do not understand. Acceleration is not the same as velocity(speed). An acceleration occurs in a turn with a constant velocity but the angular component of the vector has changed. A vector has a magnitude (velocity) and a direction(angle). A change in either is thus an acceleration.
When you go to bush air for bush and mountain training the first exercise is to stall and recover in clean and power off configuration. Then you have to recover just to stop buffeting. After flying on the edge in slow flight CC asks you to to perform a 60 degree steep turn - holding the speed NOT the altitude. Great eye opening exercise!
As both a fixed and rotary wing pilot, and aerospace engineer with 30 yrs experience including quite a bit of flight test work I’m finding this video interesting and am a little intrigued. The explanations of a (say) 1 g turn at 60 deg bank would be much better assisted with diagrams, the argument presented is correct. The challenge I have with this presentation is in a couple of different directions: 1) the description of a 90 deg bank 0 (normal) g ballistic trajectory is absolutely correct. In that case you’re accelerating downward by 9.8 m/s^2 (32 ft/s^s) with the wings vertical…essentially literally just falling like a stone. What’s not made clear is that in a 60 deg 1g turn you will be losing height at an ever increasing rate. The extent to which this is a problem depends on the circumstances. 2) The height loss during a 60 deg turn like this due to a late turn for final may cause a significantly greater challenge for an inexperienced pilot to establish a stabilised approach as you now need to add power to intercept a 3 deg final glide slope then stabilise, THEN do your finals checks with the threshold approaching. I’m thinking a 30 deg bank balanced turn where you overshoot final is less work to correct. 3) Finally, again all in the context of initial training and having a student absolutely understand what it takes to make a safe base-final turn, if they believe a 60 deg 1g turn is acceptable it may become a 60 deg balanced 2 g turn because the ground rushes up which then has a high probability, perhaps certainty, of an incipient spin with dire consequences. In summary, although I’m only picking on that one case of a base to final turn which is talked about, that may not be the place to attempt a 60deg turn unless well practiced re expected height loss and subsequent consequences of doing that. It’s also a difficult thing to provide specific guidance for a pilot in the flight manual. How would you describe this with adequate information that is readily understandable by a pilot and can be recalled from memory in those relatively rare occasions where it may be used in normal GA flying (excluding aerobatics that is)? I think this video is great, just rounding out the consequences would be a great idea. Just in case someone decides to try it if they start their final turn a bit late and is then a little startled by the ground filling the windscreen and getting wings level 100ft or (much) more below where they thought they might/should be. Cheers 😊
You make some great points, Mike. I am sure you know the intent of this videos was not to suggest that pilots should plan to use a 1 g 60-degrees-bank turn for the base-to-final turn, but to explain that stall speed is not simply a function of just bank angle. That kind of turn *can* be a good remedy (e.g. I am about to overshoot the extended centerline, and I'm also a bit too high - kill two birds with one stone). In other situations your suggestion to stay in a coordinated 30-degrees turn and correct after overshooting makes sense - but we know the temptation is there to "help" with some more rudder. Best of course to start that turn early enough that an overshoot doesn't happen to begin with. - Martin
Finally someone made a sensible comment and pointed out the absurdity of a couple of the propositions being advanced. Who in their right mind would be doing a 60 degree 1g turn in the circuit. It’s a shame that sometimes so called expert start believing their own rubbish and get other unsuspecting soles believing it too.
Excellent video. This is how military pilots are taught to fly. Every military aircraft has an AOA meter because, in the end, it's the critical AOA that determines when your aircraft is going to stall. Airspeed and angle of bank are only part of the equation.
Thanks, Gordon. I agree having an AoA indicator is great. Short of that, understanding AoA and how we affect it with elevator input is a reasonable substitute.
@@martinpauly "how we affect it with elevator input". That is the most important point and it should be part of basic training. We don't want to routinely be making steep turns (or over 30° bank) base-to -final. But if it happens, it should never result in a loss of control. Does training adequately cover how to do it safely or at least how to avoid loss of control. Apparently not.
@@warren5699 You said "We don't want to routinely be making steep turns (or over 30° bank) base-to -final." Why not? All fighter pilots turning to final in the pattern normally bank the jet to almost knife edge at less than a thousand feet altitude. You are still thinking that over 30 degrees of bank is somehow dangerous. I don't think so if you fly the aircraft correctly. If you aren't flying the aircraft correctly I suggest you get further instruction.
@@warren5699 I am in no way suggesting that a private pilot should imitate the way a military fighter pilot flys. I was merely pointing out that a high angle of bank in the pattern is not inherently dangerous. It is only dangerous when you are in a steep bank and try to hold altitude withought adding power OR flying uncoordinated at a steep bank angle and low airspeed. Most fatalities in the pattern are the result of flying slow and uncoordinated, not because of bank angle. Flying slow and uncoordinated leads to stall/spin accidents. When flying straight and level and simultaneously pushing full rudder and pulling the stick back abruptly is called a snap roll. A snap roll and a stall/spin are the same thing done at different speeds. Turning final while pulling back hard on the stick and using heavy rudder to help turn the airplane results in a stall/spin/snap roll at low altitude. THAT is what is deadly, not high bank angle.
I've just begun studying for flight training in the last two months, but I've been messing around in sims casually since I was 10. Flying and the principles of aerodynamics came second nature to me. I was always just good a physics. In my brief time reading the PHAK, I've notice a lot of vague explanations and a lot of points that weren't explicitly connected, which could have been made clearer. I made the connections on my own, tying new information later in the book to previous information, but I consistently feel those in charge of writing and editing it aren't particularly good teachers. If they really want to increase pilot understanding, and safety as a consequence, they should bring on a top notch teacher who knows how to really make abstract concepts crystal clear to anyone. You do a fantastic job of it.
Excellent video. As I put it to my students, “Whatever you do, don’t pull the stick back too far, dummy!” The designers of the Ercoupe knew what they were doing when they designed an unstallable airplane. They simply limited elevator travel. It is up to us as pilots of stallable airplanes to limit our own elevator travel to avoid unintentional stalls. I’m always amazed when I ask a pilot what stalls an airplane. The answer is always a rote answer, “when the airplane exceeds the critical angle of attack”. Then I ask what makes the airplane exceed the critical angle of attack and I get a blank stare. To which I reply, “The pilot pulling the stick back too far!”
I have experienced this with new instructors. The “pat” answer of exceeding the angle of attack is often stated without really understanding why an airfoil stalls. Emphasizing not loading up the wings or “unloading” the wings to prevent stalls would be much more valuable than “don’t exceed the critical angle of attack.”
A most excellent video. When in the pattern I always insisted that my students fly coordinated flight at all times except when a forward or crosswind slip.
The best advice I ever got was from a Mirage fighter pilot ex RAAF…. “Understanding the theory is a luxury…if the stick is back in your guts you’re stalling. Learn stick position.”
English is a very contextual language which isn't that great for scientific stuff that requires precise language. When you say something like "The slip/skid indicator goes higher", that could mean several different things depending on what you use as a point of reference. The ball can only go to the right or left relative to the position of the instrument. Since you're rotating the instrument, the ball is actually going higher relative to the ground. "The plane is banking left and the ball is moving right" is less ambiguous.
This was one of my pet peeves in training. I loved to turn final in a steep (+60°) turn and they would give me flak on the bank angle vs. stall speed and ignore that I would pull up prior to the turn, unload, roll and only use the stick to pull the airplane around while it slowed mid turn, roll out level and deploy airbrakes. Despite the manoeuvre looking dramatic from the ground I felt safer, because I was very aware of my distance towards the limit and was not encumbered by bank angle limitations and the temptation to "crab" around the turn base to final. Keep the bird fast and the load vector vertical (wrt to the a/c own frame of reference)
As for changes in Stall SPEED, my education made me look at changes in that as a matter of changes in Weight. And 3 of the main things that affect that are: 1) The actual Weight of the Plane. (What you have in it.) 2) The Center of Gravity. (Where you have that weight.) 3) The Bank Angle WHILE MAINTAINING ALTITUDE (Due to the change in the Vertical Lift Component/the G-Force increasing , pulling back on the stick/increasing the angle of attack.) Remember though, in the Pattern, people are trying to keep their altitude constant, until they start their descent, or are actually climbing on a missed approach, so changing Bank Angle would be something to keep in mind in these common circumstances. Of course, all 3 of these (and therefore Weight) are affecting the Angle of Attack, and we all know the Critical Angle of Attack doesn’t change. So I guess my comment on this would be: yeah, all those graphs and things you read/learn about Bank Angle affecting Stall Speed, is assuming your Altitude is not changing! Which is how I learned it.
The glider handbook and general practice in the US is to talk more about 45 degrees as a recommended maximum bank angle in the pattern. We also teach tools and techniques to recognize overshoot of final and fix it early by adjusting the pattern. One difference between airplanes and gliders is that airplanes typically have more elevator authority near stall speed. It may be the 30 degree recommendation for airplanes was a training shortcut vs training good recognition of load factor and AoA.
@@rockyourworld5374 Think a little bit about the subject matter and ask yourself why wingloading is relevant. The stall speeds are relatively low on gliders with low wingloading. The span makes the wing more efficient. It doesn't have much if anything to do with bank angle vs stall speed, except that it makes the aircraft tend to have lazy roll authority and tons of adverse yaw.
Indeed. Tom Knauff (famous name to those in the glider world) contends that glider stall-spin accidents in the pattern are from pilots not banking steep enough! Many (but not all) gliders will run out of elevator before stalling with steep bank angles. 45º is a very common bank angle used in gliders for thermalling and tow rope break return scenarios. It provides the least altitude loss in a turn of a given number of degrees, but the stall speed (without additional g forces beyond the 1.4 induced by the turn) increases by 19% over wings level. So it’s an important concept for a glider pilot to know. (Stall speed increase in a 1.15 G (30º bank) is only about 7%
When glider training (never finished) I had the problem that in turns past 45 degrees the nose would drop and I would accelerate and begin to lose altitude... so not a stall but a problem in the pattern... at least.it was for me as I didn't know how to counter it....
At the glider club where I have been learning to fly we use 45 degree banks on final turns in the pattern. My one instructor elligntly explained the one day exactly what you say here that if you do not try to maintain altitude your airplane will never stall. I prefer a bit less of ban being a low time pilot and sometimes not being perfectly cordinated but It makes sense and as long as you keep the airspeed constant you are fine.
Excellent video. I wish more pilots understood that 30 degrees of bank in the pattern is not the key to avoiding a stall and that AOA is. Great conversation.
The stall speed vs. bank angle charts that appear in POHs seem to be more legal protection for the manufacturer than useful information for pilots. This misunderstanding of aerodynamics and a lack of an intuitive feel of angle of attack related to load factor/stick forces has killed more pilots than probably any other single error in aviation.
Great video Martin and thanks Doug. I've always been one of those no greater than 30 degrees of bank in the pattern folks but I also understand that loading up the wings and not keeping the ball centered are the things that can really bite you quick.
Once again Martin, you & Doug have provided outstanding training materials necessary to flight safety! Doug has imparted those additional crumbs of knowledge that ties it all together. Thank you for sharing his wisdom with the platform that you have created. Thank you!!
He mentioned the stall just under critical AOA and said he could demonstrate it in a B25. He then said it would take an astronomical amount of forward pressure to recover. Is that the proper technique? How did he recover in a B25?
During spin recover training in a glider you exit the spin in a nose down attitude. I was surprised the first time i got stall buffeting during the recovery despite the nose down attitude and quite a high air speed. Entirely my fault for pulling too hard.
Your presentation is accurate and correct, but does have a failing vs the FAA model. Is does not take into account average or weak pilots. For those pilots, bank angle will always involve load therefore higher stall speeds associated with the situation. This scenario will be predominant in the pattern or during any low level work with a sad outcome. In the US stall spins are not part of the basic curriculum as it is in other countries, which have statistically lower stall-spin accidents rates than the US does. What your video discusses is a more advanced theory of flight that is indeed technically correct, but in average application, far too complicated and therefore incorrect from the perspective of said pilots. The FAA and manufactures model, simplifies a complex topic that works very well to that general population. Yours is critical to serious advanced airmen and gives them real and useful information.
Exactly! I have been saying this all my life! But it is worse: The problem with the "stall speed vs angle of bank" diagram is two fold. The bank angle doesn't increase the stall speed if you don't pull back, and for the same reasons explained even talking loosely of stall speed doesn't make any sense. Because even the stall speed for zero bank is not accurate unless you are unaccelerated. It is as true that you can stall at any speed and attitude, as it is true that you can not-stall at any speed and attitude. Typical question: What happens if you are flying 10 kts above the stall speed and you are hit by a 20 kts tailwind gust? Typical answer: You will stall Correct answer: You will not stall unless you pull back on the stick. You will be momentarily flying 10 kts below the stall speed without stalling. You will not be able to prevent the plane to pitch down and lose some altitude because your flight speed is now below your trim speed, but if you try to prevent that by pulling back you will stall. IT IS THE STICK NOT THE SPEED OR THE BANK.
Fastest way out of a stall is 0G finer words have never been spoken in my ears. Came from an AG pilot. Taught me to never force a turn with yaw or pitch changes. Famous accident in a learjet happened at Teterboro due to lack of this material. Air france was also failure of the pilots to follow a checklust after the ADC warnings were present. The supercooled water froze the pitot tubes shut.
Right - if the wings can't produce enough lift, reduce the need for lift - problem solved. As for AF447, frozen pitot tubes is how it started, but that should have been a non-event. Confusion in the cockpit leading to a stalled airliner is how it ended. - Martin
Lieber Martin! Wie immer ein super Video- vielen herzlichen Dank und liebe Grüsse aus Wien (derzeit: LIAV-LIPQ-LILF-LFMT danach noch LESU) 👍😊✈️Johannes (DEFPP)
Hi, Marty, I'm a low-time GA pilot with ~3,000 hours, but my instructor was a retired commercial pilot with over 41,000 hours. I don't find much in this presentation that my instructor didn't teach me when I was learning to fly. After watching your vid. several times to make sure I did not miss the crux of the matter, I gather that Doug agrees with the "Bank Angle and Stall Speed Myth" (including POH charts, etc.) if (1) gross weight and (2) unaccelerated flight are taken into consideration. Would it be worth his effort to write to airplane manufacturers and others who publish these charts advising them to put this qualification in their POH? I expected Doug to talk about DMMS and Vref while flying in the pattern.
This explains how I can absolutely point my bush plane's wing straight at the ground in a turn, yet have my passenger feel like they are going to fall out. The fuselage is a pretty good wing, and I am not trying to hold altitude.
Unfortunately, a large proportion of student and experienced pilots lack the necessary scientific aptitude to fully understand and apply the the full version of the story, so we have to dumb it down to an understandable level. The only other alternative is to drastically increase the amount of training and study required to be a private pilot. That will ground more than half of current pilots or aspiring pilots. This is why only a small proportion of pilots will be successful at serious aerobatic/combat flying.
Great discussion on this subject. This is a complicated concept and hopefully those teaching fully understand the dynamics of aoa load factor etc. Good work, keep these type of lessons coming. Thanks for sharing.
a major shortcoming of visualizing stall angles and airspeed is not thinking in three dimensions. A steep bank angle with a descending turn will not increase the stall speed or load factor. Flying helicopters reinforces this visualization.
Let me repeat this from the video: it doesn't matter whether you are in level flight or descending or climbing. If you want to turn with a steep bank without increasing stall speed, you have to accept a downward acceleration - which could mean a transition from level flight to a descent, or an increase in the rate of descent. A steady descent (say, 500 feet per minute) isn't enough. - Martin
Good and clear explanation, as usual. BUT... I think the point in keeping a low bank angle in the pattern is to protect against wrong inputs, or unexpected events. In few words, to have a safety margin. Pilots (all pilots, not only students, or unexperienced pilots) can make mistakes, maybe one is pulling a little during a turn, and suddenly pulls a bit more, better being at 20° bank angle than 40°. Or during a turn a sudden gust increases bank angle by 20°, if the plane was initially 15° then it will be at 35°, but if it was inially at 30° it will be 50°! And if you mix the two scenarios, even worse... So, even if the theory is clear, a pilot can over-react/mis-react on the not expected, or beacuse distracted by something, or too high workload, etc., e.g. seeing the nose going down and then pulling a little too much, in that case better being at a lower bank angle. Demonstration is that (too) many pilots keep stalling the plane when going-around too late (typically after long/high approach), instead of leaving the plane gain airspeed they pull because they see obstacles at the end of the runway, even knowing that's incorrect. What do you think?
Hello Martin and Doug from Sydney Australia. Stall speed variations Thank you for explaining the effect that the bank angle and load factor has on the planes stall speed. I am confused about whether a plane can stall vertically downward to the ground. Isn't stall about the flow of air around the airfoil (wing)? 🤨💨
John, stall is all about angle of attack - the angle between the relative wind (think "which way is the aircraft moving") and the chord line of the wing (think "which way is the aircraft pointed"). It is absolutely possible to have the aircraft pointed straight down to the earth while exceeding the critical angle of attack and stalling. Imagine flying a loop, where in the second half shortly after having reached the top you pull aggressively on the elevator. That elevator pull can point your nose straight down, but the aircraft (due to its inertia) isn't ready to move that way yet. You will stall. The way to end that stall is to relax back pressure on the elevator, which reduced the angle of attack. - Martin
To answer your question specifically, flying straight down you are in 1G flight and you have airflow over the wings and you do not need any thrust from the engine(s) as you are not trying to maintain “level” flight. YOU ARE NOT STALLED and have NOT EXCEEDED ANY CRITICAL ANGLE OF ATTACK. Fly that baby all the way to to the ground in that configuration with no fear of exceeding the “critical angle of attack.” I will add that a pilot will only be able to demonstrate that aerodynamic fact once….😊
Thank you Capt Doug. Interesting what the engineers oft know in designing 121 aircraft. Going back to the early '60s, the DC9-10 elevators were, independently TRIM tab driven. In the event of a deep stall, full forward on control column, would activate hydraulic driven elevatorS down power. Checked taxxing out, would iluminate a blue light on annunciator panel. CFI Bud KSUS
Wow! Avery interesting discussion and flying with your hands. I can see that keeps the thought straight in your thoughts. But a suggestion please. You speak of B24 angle of attack, grab a model of that to demonstrate. Surely you have one or two of those. So that we less articulate mind readers can keep up. Thanks
Technically, if you had enough speed in a 90 degree bank, and power to hang on the prop, the airplane would generate lift sideways as the top of the wing is 90 degrees to the ground. The rudder then becomes your elevator and the elevator becomes your rudder. Talk about changing functions of control surfaces during aerobatic flight.
it should be required reading. there was almost zero mention of the dangers of skidded turns from base to final during my training. and my ground school program made almost no mention either. it needs to be hammered into students' brains that the rudder is used to stay coordinated. it is NOT used to hurry up turns.
Yes, we spent weeks on location scouting, production design, wardrobe, as well as hairstyle and makeup. (I'm kidding, in case it wasn't obvious.) - Martin
Altitude permitting I love that "let the nose fall through"; JMO this must maintain altitude in training induces lots of stalls at the wrong misfortune time down the road in time. Been wrong B4.
From my experience, at least for the base-to-final turn I'm less worried about "must maintain altitude" in training (we are descending in the pattern anyway) and more about "don't bank more than 30 degrees". If we overshoot the runway, the temptation is there to force the airplane around with the rudder, and that's a recipe for a stall/spin accident. Much better to increase bank angle and unload the wings - yes, you'll lose some altitude and you'll have to eventually arrest that descent, but it beats the alternative of a spin at low altitude. - Martin
While it's certainly true, that stalling depends neither on airspeed nor on bank angle but on AOA, I still find it very advisable to limit the bank angle to 30° when flying at low altitude. Yes, it is true, that pulling on the stick is the final element in the error chain that leads to a stall. But it in most cases it is only the final element that is preceded by other errors. To prevent an accident it is worthwile to prevent all elements in the error chain. Like in the swiss cheese model where several holes must align for an accident to happen. In the pattern the aircraft is trimmed for increasingly slower speeds as we near the runway. In this configuration much less pulling is required than when flying with cruise speed because the aircraft is already trimmed for a slower speed, which means a higher AOA. So you have only a very small "pull margin". But if you apply a high bank angle, then the nose of the aircraft pitches down. And this might trigger the temptation to pull on the stick. Given the small "pull margin" this might easily lead to a stall. A high bank angle simply is not necessary in the pattern. If it is, then something is wrong and a go-around is the best solution.
@@daszieher Personally, if I need more than 30° of bank in the pattern, I feel my best option is to go around. Way too deep in the error chain already.
@@daszieher As long the pilot knows what he is doing, everything is fine. Unfortunately, sometimes this is not the case. For me, limiting the bank angle in the pattern absolutely makes sense, because it is one more layer of safety. I know, that I will still stall if I pull too much and go beyond critical AOA. But the probability that this happens is lower that way because limiting the bank angle limits the load factor that is required to maintain the flight path.
@@FlyingRagilein I understand perfectly where the limitation comes from, and - to a degree - it also makes sense. However, I have seen fellow pilots focus on a limiting factor while disregarding others. I would agree to a statement: plan your pattern in such way that you ideally make the changes in direction with only a moderate bank angle. In gliding, I have seen others pull hard will climbing on the winch and thinking that they were safe because the aircraft was above stall speed completely ignoring the fact that the winch adds AoA that you just don't "feel"...
You explained this well. Stall is a function of AOA not speed. Load factor is a huge input to this not bank. They should teach stay coordinated near the ground.
We use to do wing overs in a Beagle B121 Pup, so went over 90 degrees without any issues because we were not turning ( if I am wrong please tell me) . The bank angle in a turn is obviously the issue.
How does trim affect the g load? If I have full nose up trim, no back pressure on stick, does the full nose up trim replicate pulling on the stick? Hence, have I increased my stick back pressure?
Flight training focuses so much time on how the aircraft systems work and not enough on the how the wing works...because most flight instructors don't understand it themselves. If you are banking and not increasing AOA beyond the critical with stick/yoke back pressure the wing won't stall. If all pilots would take a UPRT course there would no longer be a myth 😊
Just curious where is Dougs hangar one reaso is I am a daytrader and get bored out of my mind so like to switch environments up now and then one environment am going to get is a daytrading office in airplane hangar set up with antique aviation relics etc maybe put a p-51 in to look and sit in etc etc etc Thanks just found channel
I never liked the charts, they mislead people to think with a narrow view. AOA needs to be taught far more than "stall speed" That, and fore/aft CG aerodynamics.
@martinpauly Very interesting discussion. One element I think is missing is power. Loading the wings in the turn definitely will impact AOA and hence airspeed and the so called stall speed, so the discussion makes sense. But if controlling vertical speed is a consideration, such as in the base to final turn, power would seem to be the more appropriate choice when turning tight. But close to the ground is not the best place for experimenting. I am interested in your further thoughts on power in this situation. Thanks!
It would be interesting to gather some footage of arriving airplanes at KOSH to illustrate the discussion in the video. Many are on the edge of something happening as they are heavily loaded, low airspeed and pilot stress/fatigue coupled with a difficult crosswind landing.
It’s all about the for e of the relative wind (speed) and it’s angle deviation or matching the longitudinal axis of the airfoil. I don’t know how he would “stall a plane pointing vertically down to the ground” though?
The question on the FAA written would be taken directly from the PHAK which includes a discussion on the factors of bank angle, increased angle of attack, load factor, and stall speed with the airplane in level flight. But the stall diagram in the POH's usually includes only the bank angle, making it appear incorrectly that bank angle is the only factor.
So when I'm turning base to final it's best to lower the nose to gain a bit of airspeed? CFI is always telling me to maintain the airspeed... great vid.. thanks
Todd, we are not saying you should always lower the nose in the base-to-final turn. But you *could* lower the nose if your airspeed is so low that turning without increasing your rate of descent would put you at the critical angle of attack (read: stall). It’s better to stay in control of a descending airplane than to lose control altogether. What your instructor is saying is carry a little extra speed in the pattern so that you can turn without also accelerating your descent.
Nudge in a little power to maintain airspeed as or if needed. Lowering pitch will control airspeed but it will also increase the rate of descent and cause the airplane to start undershooting the aiming point - not good.
Sir, Bank angle will bleed speed, when you loose speed the AOA will change you stall. 40 years ago I watched a guy fly circles at a steep bank over his fathers shop c 150, at like 900 feet, half way through he stalled and when into the building. If you do a coordinated turn at a given speed when you enter the turn your speed will bleed, I would always advise add power and shallow turning (30 deg and under).
Yes, but I'm referering to three dimentional airspace. Your answer might be relevant to cars on a circular racetrack. But I'm asking about airplanes.@@martinpauly
@@daffidavit Yes, given you were talking about 40-45 degrees bank I figured you were talking about airplanes, not cars. My answer still stands: the faster the airplane's airspeed is, the greater the turn radius. A Cessna 172 at 70 knots and 45 degrees bank will have a smaller turn radius than an F-16 doing 400 knots at the same 45 degrees bank angle.
Martin, I want to thank you for responding. The reason why I began this colloquy is because I saw knowlegable people on this channel. For years I've been arguing with some of the best aviation minds about what the FAA refers to as the "overbanking tendency." This supposedly relates to the theory that the outer wingtip has a faster airspeed than the inner wingtip in a turn. This theory mandates the use of cross controlling the airplane in EVERY turn. Just read the AIM or the Pilot's Handbood for a fable that likely began before WWII. The point I was trying to make is to dispute this theory and to see if you agree with me. Most aerobatic pilots know that the airplane's forces are balanced in a turn. The total lift vector in a turn always points to the "center" of the turn. People don't see it that way because they are used to relativistic views. That is, they are standing on the ground and see the center of the turn in the horizontal plane only. Instead, the center of the turn is somewhere else, where the total lift vector is pointing. It's kind of like the tip of an ice cream cone where the turn is at the wide end and the turn's center is at the tip of the cone. The airplane is not connected to the ground like a model airplane controlled with strings and a hand held piece of plastic. What's your position? Do you believe the outer wingtip flys faster than the inner wingtip in a turn just like propellers turn, or do you believe both wings always fly at the same air speed when the airplane is in a balanced turn? The answer to this question will determine where the center of the turn really is.@@martinpauly
The myth is that stall speed is a function of bank angle. Our answer is that is a dangerous oversimplification, correct only under certain other circumstances. - Martin
Yes, the chart might describe "narrow" conditions, but you have to start somewhere, just like your first math lesson doesn't begin with calculus. Seriously, if I were not understanding that exceeding the critical angle of attack in any flight attitude and airspeed can result in stalling the wing, then I'd invest in an approved emergency maneuver training course to help clarify the concepts. I really believe that most pilots are more knowledgeable than your video implies.
Just my 2 cents. I totally agree on its load factor. But i dont buy its mostly maintaining altitide that does it on base to final. I feel while turning base to final they use more rudder to fly a skidded turn. Once they increase bank if they were already low as soon as you start banking to hard if one over shoots the runway, the nose wants or does drop in bank & the pilot doesn't slowly pull back to "maintain altitide". Its my guess the pilot banks feels the nose headig south & instinctiveky abruptly yanks back & bam, stall spin. In this video makes it to sound that the pilot simply wished to maintain altitide instead of, "oh shit, yank the yoke back hard I'm seeing ground rushing at me & stall spins.
Of course the technical content in this video is correct, but one little nitpick: It's mentioned that "the issue is that someone might be redescent to bank the airplane when they need to" paired with the advice of "don't pull back, and as long as you just increase bank without the pull, the airplane won't stall". I have an issue with this, which is that you obviously can't get something for nothing there. In the pattern examples in the video, pilots WILL be pulling regardless because they need to make up for the lift which is lost as the lift vector comes out from directly under the plane. Of course it's correct that these charts leave out that bank angle alone isn't responsible for the increase in stall speed, but if you assume they mean a *constant altitude* bank, then they make much more sense, which is probably the intended application. Nothing against education students about that nuance, but I don't think I would want to advise my students to simply not pull to fix this issue. More over, a pattern bank angle limit of 30 degrees (soft) is set just as much to avoid loss of SA or spatial D (even in VMC!) as much as it is to avoid the issue of a low altitude stall.
The same way any stall can be ended: by reducing the angle of attack. They needed to push the nose down and restore smooth airflow over the wing - that ends the stall. Then they could have pulled the nose back up and climbed back to altitude. In stead, the AF447 pilots kept the nose on the horizon, and with the high sink rate their aircraft had, the angle of attack was too high. - Martin
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Accidental Camouflage with his shirt and the table.
I was disappointed to see the comment I was going to make was already the top comment. 😂
He said it at 6:32: "If you don't pull back on the yoke, the airplane is not going to stall." I knew this, but I'm glad to hear someone else say it, and say it very clearly. -Old retired Cessna driver and RC intro flight instructor.
When turning from base to final, the airplane is normally not holding altitude, it's descending. If you need to increase your bank, it's ok so as long as you relax the backpressure and let the nose fall a little. This is why I like to come in high from downwind to base with less power, rather than dragging it in with power. If we keep it coordinated and increase the speed slightly while descending, we can bank steeper if necessary. Better to do that than standing on the bottom rudder and keeping the bank shallow instead. IMHO.
These are some of my favorite videos on RUclips. I could listen to Doug explain flight all day.
You and I both!
- Martin
This makes so much sense. My first instructor told me don’t exceed 10 degrees while slow turning final. My second instructor said, after I kept over shooting final and being right of the centerline, bank more man. I said but I can’t go past about 10 degrees and he was like no you can, just don’t pull back on the stick. Didn’t quite understand why till now, thank you
Glad we could help clear that up. A 10-degree bank limit in turns? That sounds crazy!
- Martin
Tablecloth matches shirt… love it. Oh and yes great content.
So so good!!! It all goes back to exceeding the critical angle of attack. Too many people don't really understand the aerodynamics of flight, even after years of being a pilot. I don't think I did until I started working on my CFI rating. Thanks for taking the time to discuss and debunk the high bank angle= high stall speed myth! I really enjoy all your videos, but I really like the ones with Doug teaching and explaining. Keep the great videos coming. They are not only entertaining but they have a lot of educational value as well! Thanks Martin!
Thanks, Kevin! I’ve learned a lot from Doug over the years, and I’m so happy that I can share some of those things with the aviation community.
- Martin
Great video. Couple of points that maybe the speaker will want to address next time:
- I don't think teaching stall speed as a function of angle of bank is a disservice to private students. Most private students will forever remain private students, and some of them will go on to become private pilots who fly 20 hours a year for a couple of years until they quit forever. When you fly like that you can't realistically use any of this mathematically correct stuff. The most you can do is get it through your head that you can trust your airspeed indicator for the stall speed when you're level, and you can't trust it when you're banked. That's about it. It really doesn't make sense to try to make it any more complicated than that. You're level - watch for the bottom of the arc. You're banked - maintain whatever airspeed you're supposed to be at for this leg in the pattern and don't go any slower. Don't bank more than 30 degrees. You'll be fine. If one of a hundred students goes on to fly aerobatic jets - there will be enough time to get into more details.
- regarding this point about pilots getting in trouble in the base to final turn because they are afraid to bank and they use uncoordinated rudder inputs. This has been repeated thousands of times, but I could never understand why. Has anyone ever seen a student who uses rudder to turn? Is it ever taught to turn with rudder during primary training? For every 99 private students who don't use the rudder at all in a turn, maybe there will be 1 who uses a little to much. I can't imagine why a student who flies around with zero rudder inputs would all of a sudden start pushing bottom rudder in that base to final turn at 500 AGL. Really not seeing it.
That's a good point but incorrect use of the rudder to increase the turn rate can inadvertently happen. For one example, think about the first lesson when the controls are demonstrated. The instructor applies rudder pressures to demonstrate how the airplane yaws left and right. That could result some day in the future with that pilot using the inside rudder to increase the turn rate - not likely if the training has been good and thorough, but still possible. And it did happen on one Prog Check at our flight school long ago.
I was happy to see it mentioned that limiting banks to 30° can lead to the incorrect use of the rudder. But I was unhappy to see that that also didn't include the possible incorrect use of the elevator. When you roll into a bank, pulling on the control wheel will increase the turn rate similarly to using the inside rudder. But it costs airspeed, and I think of the two errors that can result from limiting banks, pulling on the control wheel is far more dangerous than pushing on the inside rudder because pulling on the control wheel is what causes the stall (and of course when there's also uncoordinated rudder, it will be a much more difficult, likely impossible, stall from which to recover due to the low altitude).
The concept of a Vector is one that most people do not understand. Acceleration is not the same as velocity(speed). An acceleration occurs in a turn with a constant velocity but the angular component of the vector has changed. A vector has a magnitude (velocity) and a direction(angle). A change in either is thus an acceleration.
When you go to bush air for bush and mountain training the first exercise is to stall and recover in clean and power off configuration. Then you have to recover just to stop buffeting. After flying on the edge in slow flight CC asks you to to perform a 60 degree steep turn - holding the speed NOT the altitude. Great eye opening exercise!
I hope to be attending his school this winter
As both a fixed and rotary wing pilot, and aerospace engineer with 30 yrs experience including quite a bit of flight test work I’m finding this video interesting and am a little intrigued. The explanations of a (say) 1 g turn at 60 deg bank would be much better assisted with diagrams, the argument presented is correct. The challenge I have with this presentation is in a couple of different directions:
1) the description of a 90 deg bank 0 (normal) g ballistic trajectory is absolutely correct. In that case you’re accelerating downward by 9.8 m/s^2 (32 ft/s^s) with the wings vertical…essentially literally just falling like a stone. What’s not made clear is that in a 60 deg 1g turn you will be losing height at an ever increasing rate. The extent to which this is a problem depends on the circumstances.
2) The height loss during a 60 deg turn like this due to a late turn for final may cause a significantly greater challenge for an inexperienced pilot to establish a stabilised approach as you now need to add power to intercept a 3 deg final glide slope then stabilise, THEN do your finals checks with the threshold approaching. I’m thinking a 30 deg bank balanced turn where you overshoot final is less work to correct.
3) Finally, again all in the context of initial training and having a student absolutely understand what it takes to make a safe base-final turn, if they believe a 60 deg 1g turn is acceptable it may become a 60 deg balanced 2 g turn because the ground rushes up which then has a high probability, perhaps certainty, of an incipient spin with dire consequences.
In summary, although I’m only picking on that one case of a base to final turn which is talked about, that may not be the place to attempt a 60deg turn unless well practiced re expected height loss and subsequent consequences of doing that. It’s also a difficult thing to provide specific guidance for a pilot in the flight manual. How would you describe this with adequate information that is readily understandable by a pilot and can be recalled from memory in those relatively rare occasions where it may be used in normal GA flying (excluding aerobatics that is)?
I think this video is great, just rounding out the consequences would be a great idea. Just in case someone decides to try it if they start their final turn a bit late and is then a little startled by the ground filling the windscreen and getting wings level 100ft or (much) more below where they thought they might/should be.
Cheers 😊
You make some great points, Mike. I am sure you know the intent of this videos was not to suggest that pilots should plan to use a 1 g 60-degrees-bank turn for the base-to-final turn, but to explain that stall speed is not simply a function of just bank angle. That kind of turn *can* be a good remedy (e.g. I am about to overshoot the extended centerline, and I'm also a bit too high - kill two birds with one stone). In other situations your suggestion to stay in a coordinated 30-degrees turn and correct after overshooting makes sense - but we know the temptation is there to "help" with some more rudder. Best of course to start that turn early enough that an overshoot doesn't happen to begin with.
- Martin
Finally someone made a sensible comment and pointed out the absurdity of a couple of the propositions being advanced.
Who in their right mind would be doing a 60 degree 1g turn in the circuit. It’s a shame that sometimes so called expert start believing their own rubbish and get other unsuspecting soles believing it too.
Excellent video. This is how military pilots are taught to fly. Every military aircraft has an AOA meter because, in the end, it's the critical AOA that determines when your aircraft is going to stall. Airspeed and angle of bank are only part of the equation.
Thanks, Gordon. I agree having an AoA indicator is great. Short of that, understanding AoA and how we affect it with elevator input is a reasonable substitute.
@@martinpauly "how we affect it with elevator input". That is the most important point and it should be part of basic training. We don't want to routinely be making steep turns (or over 30° bank) base-to -final. But if it happens, it should never result in a loss of control. Does training adequately cover how to do it safely or at least how to avoid loss of control. Apparently not.
@@warren5699 You said "We don't want to routinely be making steep turns (or over 30° bank) base-to -final." Why not? All fighter pilots turning to final in the pattern normally bank the jet to almost knife edge at less than a thousand feet altitude. You are still thinking that over 30 degrees of bank is somehow dangerous. I don't think so if you fly the aircraft correctly. If you aren't flying the aircraft correctly I suggest you get further instruction.
@@michaelrunnels7660 You think a 100hr Private Pilot should fly airplanes like highly trained military pilots? I don't think so.
@@warren5699 I am in no way suggesting that a private pilot should imitate the way a military fighter pilot flys. I was merely pointing out that a high angle of bank in the pattern is not inherently dangerous. It is only dangerous when you are in a steep bank and try to hold altitude withought adding power OR flying uncoordinated at a steep bank angle and low airspeed. Most fatalities in the pattern are the result of flying slow and uncoordinated, not because of bank angle. Flying slow and uncoordinated leads to stall/spin accidents. When flying straight and level and simultaneously pushing full rudder and pulling the stick back abruptly is called a snap roll. A snap roll and a stall/spin are the same thing done at different speeds. Turning final while pulling back hard on the stick and using heavy rudder to help turn the airplane results in a stall/spin/snap roll at low altitude. THAT is what is deadly, not high bank angle.
I've just begun studying for flight training in the last two months, but I've been messing around in sims casually since I was 10. Flying and the principles of aerodynamics came second nature to me. I was always just good a physics. In my brief time reading the PHAK, I've notice a lot of vague explanations and a lot of points that weren't explicitly connected, which could have been made clearer. I made the connections on my own, tying new information later in the book to previous information, but I consistently feel those in charge of writing and editing it aren't particularly good teachers. If they really want to increase pilot understanding, and safety as a consequence, they should bring on a top notch teacher who knows how to really make abstract concepts crystal clear to anyone. You do a fantastic job of it.
Thank you for the kind words!
And start saving lives!
Excellent video. As I put it to my students, “Whatever you do, don’t pull the stick back too far, dummy!” The designers of the Ercoupe knew what they were doing when they designed an unstallable airplane. They simply limited elevator travel. It is up to us as pilots of stallable airplanes to limit our own elevator travel to avoid unintentional stalls. I’m always amazed when I ask a pilot what stalls an airplane. The answer is always a rote answer, “when the airplane exceeds the critical angle of attack”. Then I ask what makes the airplane exceed the critical angle of attack and I get a blank stare. To which I reply, “The pilot pulling the stick back too far!”
I have experienced this with new instructors. The “pat” answer of exceeding the angle of attack is often stated without really understanding why an airfoil stalls. Emphasizing not loading up the wings or “unloading” the wings to prevent stalls would be much more valuable than “don’t exceed the critical angle of attack.”
A most excellent video. When in the pattern I always insisted that my students fly coordinated flight at all times except when a forward or crosswind slip.
Thank you, James.
- Martin
The best advice I ever got was from a Mirage fighter pilot ex RAAF…. “Understanding the theory is a luxury…if the stick is back in your guts you’re stalling. Learn stick position.”
If trying to understand the theory is a luxury, then I love my luxurious life. 👍
- Martin
😀
English is a very contextual language which isn't that great for scientific stuff that requires precise language. When you say something like "The slip/skid indicator goes higher", that could mean several different things depending on what you use as a point of reference. The ball can only go to the right or left relative to the position of the instrument. Since you're rotating the instrument, the ball is actually going higher relative to the ground. "The plane is banking left and the ball is moving right" is less ambiguous.
This was one of my pet peeves in training.
I loved to turn final in a steep (+60°) turn and they would give me flak on the bank angle vs. stall speed and ignore that I would pull up prior to the turn, unload, roll and only use the stick to pull the airplane around while it slowed mid turn, roll out level and deploy airbrakes.
Despite the manoeuvre looking dramatic from the ground I felt safer, because I was very aware of my distance towards the limit and was not encumbered by bank angle limitations and the temptation to "crab" around the turn base to final.
Keep the bird fast and the load vector vertical (wrt to the a/c own frame of reference)
As for changes in Stall SPEED, my education made me look at changes in that as a matter of changes in Weight. And 3 of the main things that affect that are:
1) The actual Weight of the Plane. (What you have in it.)
2) The Center of Gravity. (Where you have that weight.)
3) The Bank Angle WHILE MAINTAINING ALTITUDE (Due to the change in the Vertical Lift Component/the G-Force increasing , pulling back on the stick/increasing the angle of attack.) Remember though, in the Pattern, people are trying to keep their altitude constant, until they start their descent, or are actually climbing on a missed approach, so changing Bank Angle would be something to keep in mind in these common circumstances.
Of course, all 3 of these (and therefore Weight) are affecting the Angle of Attack, and we all know the Critical Angle of Attack doesn’t change.
So I guess my comment on this would be: yeah, all those graphs and things you read/learn about Bank Angle affecting Stall Speed, is assuming your Altitude is not changing! Which is how I learned it.
The glider handbook and general practice in the US is to talk more about 45 degrees as a recommended maximum bank angle in the pattern. We also teach tools and techniques to recognize overshoot of final and fix it early by adjusting the pattern. One difference between airplanes and gliders is that airplanes typically have more elevator authority near stall speed. It may be the 30 degree recommendation for airplanes was a training shortcut vs training good recognition of load factor and AoA.
Yes, that is because the wing span of glider is 3 times that of a warrior and the wing loading is 1/3 . On decent size glider that is.
@@rockyourworld5374 Think a little bit about the subject matter and ask yourself why wingloading is relevant. The stall speeds are relatively low on gliders with low wingloading. The span makes the wing more efficient. It doesn't have much if anything to do with bank angle vs stall speed, except that it makes the aircraft tend to have lazy roll authority and tons of adverse yaw.
Indeed. Tom Knauff (famous name to those in the glider world) contends that glider stall-spin accidents in the pattern are from pilots not banking steep enough! Many (but not all) gliders will run out of elevator before stalling with steep bank angles.
45º is a very common bank angle used in gliders for thermalling and tow rope break return scenarios. It provides the least altitude loss in a turn of a given number of degrees, but the stall speed (without additional g forces beyond the 1.4 induced by the turn) increases by 19% over wings level. So it’s an important concept for a glider pilot to know. (Stall speed increase in a 1.15 G (30º bank) is only about 7%
When glider training (never finished) I had the problem that in turns past 45 degrees the nose would drop and I would accelerate and begin to lose altitude... so not a stall but a problem in the pattern... at least.it was for me as I didn't know how to counter it....
At the glider club where I have been learning to fly we use 45 degree banks on final turns in the pattern. My one instructor elligntly explained the one day exactly what you say here that if you do not try to maintain altitude your airplane will never stall. I prefer a bit less of ban being a low time pilot and sometimes not being perfectly cordinated but It makes sense and as long as you keep the airspeed constant you are fine.
Excellent video. I wish more pilots understood that 30 degrees of bank in the pattern is not the key to avoiding a stall and that AOA is. Great conversation.
Thanks alot for addressing this subject, it's one of the most important for any pilot .
Glad you enjoyed this one!
- Martin
The stall speed vs. bank angle charts that appear in POHs seem to be more legal protection for the manufacturer than useful information for pilots. This misunderstanding of aerodynamics and a lack of an intuitive feel of angle of attack related to load factor/stick forces has killed more pilots than probably any other single error in aviation.
Great video Martin and thanks Doug. I've always been one of those no greater than 30 degrees of bank in the pattern folks but I also understand that loading up the wings and not keeping the ball centered are the things that can really bite you quick.
Specially if inside wing is blocked due to skid
Once again Martin, you & Doug have provided outstanding training materials necessary to flight safety! Doug has imparted those additional crumbs of knowledge that ties it all together. Thank you for sharing his wisdom with the platform that you have created. Thank you!!
You are very welcome, Benjamin!
- Martin
He mentioned the stall just under critical AOA and said he could demonstrate it in a B25. He then said it would take an astronomical amount of forward pressure to recover. Is that the proper technique? How did he recover in a B25?
Awesome video! Nice job matching Doug’s shirt to the table cloth 🤙
Thanks for noticing our intense planning of production details, stage settings and wardrobe! 🤣
- Martin
@@martinpauly haha. Love it.
During spin recover training in a glider you exit the spin in a nose down attitude. I was surprised the first time i got stall buffeting during the recovery despite the nose down attitude and quite a high air speed. Entirely my fault for pulling too hard.
That's a great example of how one can stall an aircraft in ANY attitude. I've experienced the same thing in a glider.
- Martin
You might want to sign up for a sleep study... You might have Sleep Apnea. ;-)
Your presentation is accurate and correct, but does have a failing vs the FAA model. Is does not take into account average or weak pilots. For those pilots, bank angle will always involve load therefore higher stall speeds associated with the situation. This scenario will be predominant in the pattern or during any low level work with a sad outcome. In the US stall spins are not part of the basic curriculum as it is in other countries, which have statistically lower stall-spin accidents rates than the US does. What your video discusses is a more advanced theory of flight that is indeed technically correct, but in average application, far too complicated and therefore incorrect from the perspective of said pilots. The FAA and manufactures model, simplifies a complex topic that works very well to that general population. Yours is critical to serious advanced airmen and gives them real and useful information.
Exactly! I have been saying this all my life!
But it is worse: The problem with the "stall speed vs angle of bank" diagram is two fold. The bank angle doesn't increase the stall speed if you don't pull back, and for the same reasons explained even talking loosely of stall speed doesn't make any sense. Because even the stall speed for zero bank is not accurate unless you are unaccelerated.
It is as true that you can stall at any speed and attitude, as it is true that you can not-stall at any speed and attitude.
Typical question: What happens if you are flying 10 kts above the stall speed and you are hit by a 20 kts tailwind gust?
Typical answer: You will stall
Correct answer: You will not stall unless you pull back on the stick. You will be momentarily flying 10 kts below the stall speed without stalling. You will not be able to prevent the plane to pitch down and lose some altitude because your flight speed is now below your trim speed, but if you try to prevent that by pulling back you will stall.
IT IS THE STICK NOT THE SPEED OR THE BANK.
Great video content. Also great video-setup. His shirt perfectly matching the tablecloth is art!
Thanks for noticing - we spend weeks on set decoration and wardrobe for these productions! 🤣
- Martin
Fastest way out of a stall is 0G finer words have never been spoken in my ears. Came from an AG pilot. Taught me to never force a turn with yaw or pitch changes. Famous accident in a learjet happened at Teterboro due to lack of this material. Air france was also failure of the pilots to follow a checklust after the ADC warnings were present. The supercooled water froze the pitot tubes shut.
Right - if the wings can't produce enough lift, reduce the need for lift - problem solved.
As for AF447, frozen pitot tubes is how it started, but that should have been a non-event. Confusion in the cockpit leading to a stalled airliner is how it ended.
- Martin
I was made aware of this in my training 33 years ago what’s happened to the instructing game.
Lieber Martin!
Wie immer ein super Video- vielen herzlichen Dank und liebe Grüsse aus Wien (derzeit: LIAV-LIPQ-LILF-LFMT danach noch LESU)
👍😊✈️Johannes (DEFPP)
Vielen Dank, Johannes - und viel Erfolg für Deinen Flug! (Vielleicht bist Du auch inzwischen ja wieder zu Hause.)
- Martin
Thanks Martin and Doug for yet another very informative discussion.
You do such a great job putting these videos together.
Thank you, Kevin. Glad you like how it turned out.
- Martin
Flying slow with big angle of attack, here in France they call it “seconde regime”, it requires lots of power. Can be used to land in a shorter field.
Hi, Marty, I'm a low-time GA pilot with ~3,000 hours, but my instructor was a retired commercial pilot with over 41,000 hours. I don't find much in this presentation that my instructor didn't teach me when I was learning to fly. After watching your vid. several times to make sure I did not miss the crux of the matter, I gather that Doug agrees with the "Bank Angle and Stall Speed Myth" (including POH charts, etc.) if (1) gross weight and (2) unaccelerated flight are taken into consideration. Would it be worth his effort to write to airplane manufacturers and others who publish these charts advising them to put this qualification in their POH? I expected Doug to talk about DMMS and Vref while flying in the pattern.
Love the table cloth shirt.;)
This explains how I can absolutely point my bush plane's wing straight at the ground in a turn, yet have my passenger feel like they are going to fall out. The fuselage is a pretty good wing, and I am not trying to hold altitude.
Unfortunately, a large proportion of student and experienced pilots lack the necessary scientific aptitude to fully understand and apply the the full version of the story, so we have to dumb it down to an understandable level. The only other alternative is to drastically increase the amount of training and study required to be a private pilot. That will ground more than half of current pilots or aspiring pilots. This is why only a small proportion of pilots will be successful at serious aerobatic/combat flying.
Such an informative video as always- I can't wait for the next.
I also can't help but notice how nicely Doug is matching the tablecloth :)
Great discussion on this subject. This is a complicated concept and hopefully those teaching fully understand the dynamics of aoa load factor etc. Good work, keep these type of lessons coming. Thanks for sharing.
Thanks, Ken!
- Martin
Great video! A very misunderstood topic that you clearly explained..
First time I've seen one of your videos, and I'm highly impressed! What a great explanation!
Most illuminating discussion Martin - helps so much for folks to understand airfoils and air flow characteristics etc.
Thanks, Chris.
- Martin
Your explanations are just fantastic!
It makes all the sense! Thanks for sharing this wisdom with us!
Hey Martin great video like always. Video quality also great, thanks
Great training video. Thanks!
a major shortcoming of visualizing stall angles and airspeed is not thinking in three dimensions. A steep bank angle with a descending turn will not increase the stall speed or load factor. Flying helicopters reinforces this visualization.
Let me repeat this from the video: it doesn't matter whether you are in level flight or descending or climbing. If you want to turn with a steep bank without increasing stall speed, you have to accept a downward acceleration - which could mean a transition from level flight to a descent, or an increase in the rate of descent. A steady descent (say, 500 feet per minute) isn't enough.
- Martin
Good and clear explanation, as usual. BUT...
I think the point in keeping a low bank angle in the pattern is to protect against wrong inputs, or unexpected events. In few words, to have a safety margin. Pilots (all pilots, not only students, or unexperienced pilots) can make mistakes, maybe one is pulling a little during a turn, and suddenly pulls a bit more, better being at 20° bank angle than 40°. Or during a turn a sudden gust increases bank angle by 20°, if the plane was initially 15° then it will be at 35°, but if it was inially at 30° it will be 50°! And if you mix the two scenarios, even worse...
So, even if the theory is clear, a pilot can over-react/mis-react on the not expected, or beacuse distracted by something, or too high workload, etc., e.g. seeing the nose going down and then pulling a little too much, in that case better being at a lower bank angle. Demonstration is that (too) many pilots keep stalling the plane when going-around too late (typically after long/high approach), instead of leaving the plane gain airspeed they pull because they see obstacles at the end of the runway, even knowing that's incorrect.
What do you think?
Hello Martin and Doug from Sydney Australia.
Stall speed variations
Thank you for explaining the effect that the bank angle and load factor has on the planes stall speed.
I am confused about whether a plane can stall vertically downward to the ground. Isn't stall about the flow of air around the airfoil (wing)?
🤨💨
John, stall is all about angle of attack - the angle between the relative wind (think "which way is the aircraft moving") and the chord line of the wing (think "which way is the aircraft pointed"). It is absolutely possible to have the aircraft pointed straight down to the earth while exceeding the critical angle of attack and stalling. Imagine flying a loop, where in the second half shortly after having reached the top you pull aggressively on the elevator. That elevator pull can point your nose straight down, but the aircraft (due to its inertia) isn't ready to move that way yet. You will stall. The way to end that stall is to relax back pressure on the elevator, which reduced the angle of attack.
- Martin
To answer your question specifically, flying straight down you are in 1G flight and you have airflow over the wings and you do not need any thrust from the engine(s) as you are not trying to maintain “level” flight. YOU ARE NOT STALLED and have NOT EXCEEDED ANY CRITICAL ANGLE OF ATTACK. Fly that baby all the way to to the ground in that configuration with no fear of exceeding the “critical angle of attack.” I will add that a pilot will only be able to demonstrate that aerodynamic fact once….😊
Thank you Capt Doug.
Interesting what the engineers oft know in designing 121 aircraft.
Going back to the early '60s, the DC9-10 elevators were, independently TRIM tab driven.
In the event of a deep stall, full forward on control column, would activate hydraulic driven elevatorS down power. Checked taxxing out, would iluminate a blue light on annunciator panel.
CFI Bud KSUS
That is all well and good. The point is: If the aircraft cannot follow the desired trajectory, the aircraft is "stalled".
A lot of knowledge from both of you, thanks for sharing.
Wow! Avery interesting discussion and flying with your hands. I can see that keeps the thought straight in your thoughts. But a suggestion please. You speak of B24 angle of attack, grab a model of that to demonstrate. Surely you have one or two of those. So that we less articulate mind readers can keep up. Thanks
Technically, if you had enough speed in a 90 degree bank, and power to hang on the prop, the airplane would generate lift sideways as the top of the wing is 90 degrees to the ground. The rudder then becomes your elevator and the elevator becomes your rudder. Talk about changing functions of control surfaces during aerobatic flight.
It's how they perform at airshow demonstrations.
I would love to see him do a “STICK & RUDDER “ deep dive. I love that book and shock that I hear so few have read it.
it should be required reading. there was almost zero mention of the dangers of skidded turns from base to final during my training. and my ground school program made almost no mention either. it needs to be hammered into students' brains that the rudder is used to stay coordinated. it is NOT used to hurry up turns.
Thank You for the Informative Video.
Is the matching shirt and table cloth deliberate?
Yes, we spent weeks on location scouting, production design, wardrobe, as well as hairstyle and makeup. (I'm kidding, in case it wasn't obvious.)
- Martin
Altitude permitting I love that "let the nose fall through"; JMO this must maintain altitude in training induces lots of stalls at the wrong misfortune time down the road in time. Been wrong B4.
From my experience, at least for the base-to-final turn I'm less worried about "must maintain altitude" in training (we are descending in the pattern anyway) and more about "don't bank more than 30 degrees". If we overshoot the runway, the temptation is there to force the airplane around with the rudder, and that's a recipe for a stall/spin accident. Much better to increase bank angle and unload the wings - yes, you'll lose some altitude and you'll have to eventually arrest that descent, but it beats the alternative of a spin at low altitude.
- Martin
While it's certainly true, that stalling depends neither on airspeed nor on bank angle but on AOA, I still find it very advisable to limit the bank angle to 30° when flying at low altitude. Yes, it is true, that pulling on the stick is the final element in the error chain that leads to a stall. But it in most cases it is only the final element that is preceded by other errors. To prevent an accident it is worthwile to prevent all elements in the error chain. Like in the swiss cheese model where several holes must align for an accident to happen. In the pattern the aircraft is trimmed for increasingly slower speeds as we near the runway. In this configuration much less pulling is required than when flying with cruise speed because the aircraft is already trimmed for a slower speed, which means a higher AOA. So you have only a very small "pull margin". But if you apply a high bank angle, then the nose of the aircraft pitches down. And this might trigger the temptation to pull on the stick. Given the small "pull margin" this might easily lead to a stall. A high bank angle simply is not necessary in the pattern. If it is, then something is wrong and a go-around is the best solution.
I think otherwise. The limitation to 30° is what causes pilots to "crab" around turns base to final and what gets them killed in a stall/spin.
@@daszieher Personally, if I need more than 30° of bank in the pattern, I feel my best option is to go around. Way too deep in the error chain already.
@@FlyingRagilein I used to bank harder deliberately (obviously one should check speed and loading).
@@daszieher As long the pilot knows what he is doing, everything is fine. Unfortunately, sometimes this is not the case. For me, limiting the bank angle in the pattern absolutely makes sense, because it is one more layer of safety. I know, that I will still stall if I pull too much and go beyond critical AOA. But the probability that this happens is lower that way
because limiting the bank angle limits the load factor that is required to maintain the flight path.
@@FlyingRagilein I understand perfectly where the limitation comes from, and - to a degree - it also makes sense. However, I have seen fellow pilots focus on a limiting factor while disregarding others.
I would agree to a statement: plan your pattern in such way that you ideally make the changes in direction with only a moderate bank angle.
In gliding, I have seen others pull hard will climbing on the winch and thinking that they were safe because the aircraft was above stall speed completely ignoring the fact that the winch adds AoA that you just don't "feel"...
Great stuff, Martin! Thank you very much. Always love your videos!
You explained this well. Stall is a function of AOA not speed. Load factor is a huge input to this not bank.
They should teach stay coordinated near the ground.
That’s why every pilot should have some basic aerobatic training!! Oh! It’s also fun!
We use to do wing overs in a Beagle B121 Pup, so went over 90 degrees without any issues because we were not turning ( if I am wrong please tell me) . The bank angle in a turn is obviously the issue.
Just wanted to say the same with my Bulldog. 🙂
How does trim affect the g load? If I have full nose up trim, no back pressure on stick, does the full nose up trim replicate pulling on the stick? Hence, have I increased my stick back pressure?
Trim would essentially no impact on the stall speed. It would have a huge impact on the stick force required.
Excellent discussion.
Flight training focuses so much time on how the aircraft systems work and not enough on the how the wing works...because most flight instructors don't understand it themselves. If you are banking and not increasing AOA beyond the critical with stick/yoke back pressure the wing won't stall. If all pilots would take a UPRT course there would no longer be a myth 😊
Yes, upset recovery training would be a good thing for all pilots!
- Martin
Just curious where is Dougs hangar one reaso is I am a daytrader and get bored out of my mind so like to switch environments up now and then one environment am going to get is a daytrading office in airplane hangar set up with antique aviation relics etc maybe put a p-51 in to look and sit in etc etc etc Thanks just found channel
I never liked the charts, they mislead people to think with a narrow view. AOA needs to be taught far more than "stall speed"
That, and fore/aft CG aerodynamics.
@martinpauly Very interesting discussion. One element I think is missing is power. Loading the wings in the turn definitely will impact AOA and hence airspeed and the so called stall speed, so the discussion makes sense. But if controlling vertical speed is a consideration, such as in the base to final turn, power would seem to be the more appropriate choice when turning tight. But close to the ground is not the best place for experimenting. I am interested in your further thoughts on power in this situation. Thanks!
It would be interesting to gather some footage of arriving airplanes at KOSH to illustrate the discussion in the video. Many are on the edge of something happening as they are heavily loaded, low airspeed and pilot stress/fatigue coupled with a difficult crosswind landing.
Martin needs a grey striped shirt !
It’s all about the for e of the relative wind (speed) and it’s angle deviation or matching the longitudinal axis of the airfoil. I don’t know how he would “stall a plane pointing vertically down to the ground” though?
Some good hanger flying Thxs Martin!
I really enjoy these videos.. every one gives me a bit more knowledge that I wouldn't have had before..
It is a question that the faa knowledge test requires you to say “it increases with bank angle.”
The question on the FAA written would be taken directly from the PHAK which includes a discussion on the factors of bank angle, increased angle of attack, load factor, and stall speed with the airplane in level flight. But the stall diagram in the POH's usually includes only the bank angle, making it appear incorrectly that bank angle is the only factor.
Hang on Ronnie !!
Most excellent!
Most any free flight modeler learns that one adjustment for a stall glide pattern is to tighten the turn.
So when I'm turning base to final it's best to lower the nose to gain a bit of airspeed? CFI is always telling me to maintain the airspeed... great vid.. thanks
Todd, we are not saying you should always lower the nose in the base-to-final turn. But you *could* lower the nose if your airspeed is so low that turning without increasing your rate of descent would put you at the critical angle of attack (read: stall). It’s better to stay in control of a descending airplane than to lose control altogether.
What your instructor is saying is carry a little extra speed in the pattern so that you can turn without also accelerating your descent.
Nudge in a little power to maintain airspeed as or if needed. Lowering pitch will control airspeed but it will also increase the rate of descent and cause the airplane to start undershooting the aiming point - not good.
Martin, this is very non-intuitive stuff. Which instrument(s) can keep one out of trouble then?
Angle of attack indicator is a good start.
Sir, Bank angle will bleed speed, when you loose speed the AOA will change you stall. 40 years ago I watched a guy fly circles at a steep bank over his fathers shop c 150, at like 900 feet, half way through he stalled and when into the building. If you do a coordinated turn at a given speed when you enter the turn your speed will bleed, I would always advise add power and shallow turning (30 deg and under).
Only if you try to maintain altitude.
So many nuggets in this video. Ty
In a medium to steeply banked turn, lets say approx. 40-45 degrees, where is the point in space where the center of the turn is?
That depends on the airspeed. The faster your speed, the greater the turn radius will be.
- Martin
You didn't answer my question. we are in three-dimensional space. @@martinpauly
Yes, but I'm referering to three dimentional airspace. Your answer might be relevant to cars on a circular racetrack. But I'm asking about airplanes.@@martinpauly
@@daffidavit Yes, given you were talking about 40-45 degrees bank I figured you were talking about airplanes, not cars. My answer still stands: the faster the airplane's airspeed is, the greater the turn radius. A Cessna 172 at 70 knots and 45 degrees bank will have a smaller turn radius than an F-16 doing 400 knots at the same 45 degrees bank angle.
Martin, I want to thank you for responding. The reason why I began this colloquy is because I saw knowlegable people on this channel. For years I've been arguing with some of the best aviation minds about what the FAA refers to as the "overbanking tendency." This supposedly relates to the theory that the outer wingtip has a faster airspeed than the inner wingtip in a turn. This theory mandates the use of cross controlling the airplane in EVERY turn. Just read the AIM or the Pilot's Handbood for a fable that likely began before WWII.
The point I was trying to make is to dispute this theory and to see if you agree with me. Most aerobatic pilots know that the airplane's forces are balanced in a turn. The total lift vector in a turn always points to the "center" of the turn. People don't see it that way because they are used to relativistic views. That is, they are standing on the ground and see the center of the turn in the horizontal plane only. Instead, the center of the turn is somewhere else, where the total lift vector is pointing. It's kind of like the tip of an ice cream cone where the turn is at the wide end and the turn's center is at the tip of the cone. The airplane is not connected to the ground like a model airplane controlled with strings and a hand held piece of plastic.
What's your position? Do you believe the outer wingtip flys faster than the inner wingtip in a turn just like propellers turn, or do you believe both wings always fly at the same air speed when the airplane is in a balanced turn? The answer to this question will determine where the center of the turn really is.@@martinpauly
That myth wasn’t as clear cut as the ‘downwind speed drop’ myth. The important point was made that stalling is all about the AoA.
The myth is that stall speed is a function of bank angle. Our answer is that is a dangerous oversimplification, correct only under certain other circumstances.
- Martin
Yes, the chart might describe "narrow" conditions, but you have to start somewhere, just like your first math lesson doesn't begin with calculus. Seriously, if I were not understanding that exceeding the critical angle of attack in any flight attitude and airspeed can result in stalling the wing, then I'd invest in an approved emergency maneuver training course to help clarify the concepts. I really believe that most pilots are more knowledgeable than your video implies.
Just my 2 cents.
I totally agree on its load factor.
But i dont buy its mostly maintaining altitide that does it on base to final.
I feel while turning base to final they use more rudder to fly a skidded turn. Once they increase bank if they were already low as soon as you start banking to hard if one over shoots the runway, the nose wants or does drop in bank & the pilot doesn't slowly pull back to "maintain altitide".
Its my guess the pilot banks feels the nose headig south & instinctiveky abruptly yanks back & bam, stall spin.
In this video makes it to sound that the pilot simply wished to maintain altitide instead of, "oh shit, yank the yoke back hard I'm seeing ground rushing at me & stall spins.
My personal viewpoint has been that critical angle of attack defines the performance envelope of the aircraft.
Of course the technical content in this video is correct, but one little nitpick: It's mentioned that "the issue is that someone might be redescent to bank the airplane when they need to" paired with the advice of "don't pull back, and as long as you just increase bank without the pull, the airplane won't stall". I have an issue with this, which is that you obviously can't get something for nothing there. In the pattern examples in the video, pilots WILL be pulling regardless because they need to make up for the lift which is lost as the lift vector comes out from directly under the plane.
Of course it's correct that these charts leave out that bank angle alone isn't responsible for the increase in stall speed, but if you assume they mean a *constant altitude* bank, then they make much more sense, which is probably the intended application. Nothing against education students about that nuance, but I don't think I would want to advise my students to simply not pull to fix this issue. More over, a pattern bank angle limit of 30 degrees (soft) is set just as much to avoid loss of SA or spatial D (even in VMC!) as much as it is to avoid the issue of a low altitude stall.
i fell asleep 5 times listening to these 2
Glad we could help with your insomnia 👍
- Martin
Anytime you have back pressure on the stick. Think stall
The problem is banking right above Vs and not losing altitude without power. Look at him lost 1,200 feet with banking and rudder!
Good points.
Martin, I have not heard you speak in some time. Your Deutsch ausprache ist ganz verschwunden😢😅
What should really be said is that bank does not increase stall speed provided the wing remains at or below one G of lift.
I think that IS what we say in the video.
- Martin
@@martinpauly The idea is similar. But I did not hear it said that way.
So how would have Air France recovered ?
The same way any stall can be ended: by reducing the angle of attack. They needed to push the nose down and restore smooth airflow over the wing - that ends the stall. Then they could have pulled the nose back up and climbed back to altitude. In stead, the AF447 pilots kept the nose on the horizon, and with the high sink rate their aircraft had, the angle of attack was too high.
- Martin
It's not a myth. it simply ONLY applies to turns while holding altitude.
It also applies to turns in a steady descent or climb ("steady" as in with a constant vertical speed).
- Martin
@@martinpauly I suppose you're right, as you'd be at 1G then as well (vertical).
So it’s not an actual angle to watch out for. Rather it’s a question of how loaded are the wings?
Load factor it’s all load factor. Unload the wings and it won’t stall