Quarantine boredom brought words about flying technique to me, so I decided to write them down. One of the often missed aspects of tailwheel flying that I have observed in folks flying the friendly skies in these dynamically unstable beasts is the importance of aileron in keeping the aircraft straight. Here's some words on that:

See the link for the actual blog post:
https://generalaviator.blog/2020/03/26/tailwheel-its-not-just-the-rudder-dummy/

Or read it here (note the actual blog has links to some example videos; worth a look):

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Ask any tailwheel pilot what the most important control axis (aileron, elevator, or rudder) is during a landing and you will most certainly get an emphatic “Rudder!”. But in that quick response lies a problem, and the source of so many bent, ground looped, or otherwise damaged, taildraggers.

Read the NTSB reports for tailwheel landing accidents and common themes appear in the pilot accounts: “the airplane veered”; “corrected with opposite rudder and brake”; “overcorrected”; “the aircraft departed the runway surface”; “the airplane ground looped”. What strikes fear in us as tailwheel pilots reading these accounts is the suddenness of this “veer” that these pilots all speak of. And the apparent powerlessness that they encountered as they relied on their tried-and-true instincts to correct for what was happening. But alas, with the rudder pedal at the stops, and maybe even some timely brake inputs, they were unable to save the airplane that day. They lost it.

Funny though, in most all of the accounts you read, never is an aileron input mentioned. Sure, what is happening, as the pilot can plainly see, is a sudden change in the yaw rate of the aircraft. Yaw equals rudder, and the instincts we’ve been taught tell us rudder is the input that controls yaw. A full boot of opposite rudder is immediately commanded, and through the magic of reversible flight controls, results in an immediate output at the tail. Just as we’ve been trained to expect.

But, let’s back up a few potatoes. To the moments before the pilot detected the yaw rate, in fact, let’s back up to precisely the moment before the the yaw rate initiated. At this moment, the condition of the aircraft is such: it is traveling forwards in space, and, by our bounding conditions, is not rotating about its vertical axis. So what is going to cause the aircraft to develop yaw rate? Well in the case of our demon the ground loop, it’s usually one of two scenarios (or the mix of the two if you really want to bend a plane that day):

The first is the most familiar to the tailwheel pilot: not touching down straight. It’s the fundamental credo of the tailwheel pilot that under his or her command, the aircraft WILL touchdown straight. In technical terms, straight means keeping the longitudinal axis of the aircraft parallel with its track across the ground – in other words, keeping the wheels aligned with the direction of motion. If not straight, the wheels being forward of the CG, when in contact with the ground, will create a yaw moment. If at anytime during the landing roll things aren’t “straight”, corrections must be made by the pilot. Pretty straight-forward (ha).

The second scenario though isn’t as often discussed. And it’s the one that really gets people, because like all good gotchas in aviation, it’s insidious. For the astute tailwheel driver, it’s the piece of information that tells so much about what is soon to happen to the aircraft: The bank angle.

Now, the bank angle scenario of course goes hand-in-hand with a crosswind landing, so the discussion will start there. When a plane lands straight (as previously defined) in a crosswind, there will inherently be sideslip (Beta as we call it in Aerodyamics) on the aircraft. Explicitly, the relative wind is coming from a direction not parallel to the aircraft’s longitudinal axis. What this does is expose the upwind wing to a very clean expanse of air while the fuselage partially blanks the flow over the downwind wing. Additionally, a side force develops on the fuselage. The net result of these two phenomna is a rolling moment away from the wind. Of course, all the while the weathervane effect of that big rudder surface is also doing its part to yaw the aircraft into the wind, but you’re a good tailwheel pilot and the lizard brain is already taking care of that with the rudder (or so it thinks).

Now, say the astute pilot notices this bank (caused by crosswind or otherwise), what do they do? Apply aileron to counter it of course! And a happy easy landing is made. But the less astute pilot doesn’t notice it. The aileron remains neutral. And perhaps the landing works out, perhaps it’s a little exciting, or perhaps it’s too exciting and around the plane goes. Sounds like the aileron did something, but the bank angle was so small, how did that really make all the difference trying to correct for it?

It’s only partially about the bank. The bank is a sort of red herring. A few things happen when that bank develops, and it affects pilots differently. For one, there’s an illusion. As the aircraft develops that slight bank, for many tailwheel flyers, especially novice ones, it messes with perspective. The ability to discern what straight is becomes out-of-whack, and without knowing it, they are no longer tracking straight. Not straight, yaw moment develops, and the classic scenario begins to unfold. But physics also comes into play, and those familiar with weight transfer in car racing will catch on quick here. You see as that bank develops, more of the weight and aerodynamic forces that are being reacted by the landing gear are shifted to the downwind wheel. And tires being what they are, always slipping, will slip less as the weight on them increases. As the tire becomes loaded up, it more efficiently reacts those side forces back into the gear leg; thus for a given amount of tire slip angle, the amount of lateral force (yaw moment) generated is greater…perhaps too great for the rudder to overcome! (Damp grass runways sound so nice right about now).

Oh, but there’s more to these silly ailerons when landing. And when in doubt, always try more. Remember back to the early days of your flight training as you learned about coordinating the aircraft’s 3 axis in the air. As with all thing in life and flying, it was a give and take. The 3 control axis, while independent in the surfaces they move (usually), each affected the response of the aircraft in all 3 axis in one way or another. Deflecting those ailerons almost always caused a little bit of yaw opposite the bank. Adversely as we call it. The simple answer to this holds true, the downward deflecting aileron, way out on the end of the wing, creates more drag than the upward deflecting one, resulting in a yaw moment opposite of the bank. Hey, wait a minute, yaw moment opposite of the bank? That sure sounds like exactly what is needed in a crosswind landing. Bingo!

Of course, the amount of yaw from the ailerons varies from plane to plane. In the modern era, adverse yaw has been beaten out of the aerodynamics of those craft to the best of aero engineer’s capabilities. But thankfully our old trusty taildraggers are usual not in that category and many of our ilk have gobs of adverse yaw for us to use. So use it! Every time you land, note the wind and pour on that aileron. And don’t relax it till you roll to a stop…why would you give up free directional control?

My method: put in all the aileron, if the downwind wheel begins to lift, back off. Increase your input as the airspeed decays and hold to the stop until the plane is slowed.

I have ranted enough. Time for some demonstration. YouTube, through the efforts of some planespotter and some very honest pilots, affords us some fabulous footage of such ground loop events. Let’s take a look: https://generalaviator.blog/2020/03/26/tailwheel-its-not-just-the-rudder-dummy/

I read this I guess when you first published it. I liked it then, I like it now. I am in total agreement.

Thanks !

Wolfgang himself couldn't have said it better...Nice work Fiddler!

Good point Fiddler, about using aileron against crosswind on final and even more aileron against crosswind when slowing down after touchdown and when slow during the early stages of takeoff. Also a good group of ground loop videos.

As you pointed out, touching down crooked, as the crabbing Stearman and the wing wagging Maule, is worst because of speed. The 1.3 Vso to round out technique contributes to the too fast touchdown unless there is plenty of remaining runway and the student holds off until very low in ground effect stall airspeed, far below Vso.

I very much agree that slight crosswind causes more ground loops than does strong crosswind. Pilots are far less likely to attempt coordinated turns to stay on the centerline extended, as did the Maule. Some like to crab and just side slip on short final, but that is directing our butt to the numbers with rudder. Either crab or side slip in a definite crosswind creates less problem.

Full aileron into the wind on the ground needs to be proactive, just like walking the rudder. Late with rudder, aileron into the wind, brakes, and/or power is reactive, an emergency attempt to correct the error of not being proactive.

Again, good lesson.

Great explanation of a commonly underestimated technique. I too was taught to add aileron into until the downwind tire is coming up or at least very light. While I admit I am not using this skill as much as I should. I am getting better. Thanks for the refresh.

Fiddler, great post. I bookmarked your blog entry FWIW.

I have about 8000 TT, 2000 hours in Super Cubs and 180s, and it pains me to say that, at about the 1801 TW time mark, I looped my 180. Luckily no damage was done, except to my pride. It was "substantial damage."

I'm pretty careful and try to stay within the recommended crosswind limit that the manual states. I landed at my home field one day when the wind was gusty out of the northwest, about 70 degrees off the paved runway. I wasn't feeling particularly sharp that day but I was aware of the threat. And, there's no AWOS/ASOS on the airfield, so I didn't know exactly what the wind was. Somewhere in the 12-15 kt crosswind range. Best I can recall, and I wrote it down when it happened, is this: I made a conscious decision to land where I knew the wind was close to or out of the max recommendation. I touched down fine, and I buried the aileron. But then the downwind wing started to rise. I backed off the aileron, and then I started to ground loop. Full rudder and brake were to no avail at this point and around we went.

What's important in all this is to say what would I do next time. Next time I will (NTIW): look for a place more in line with the wind, angle across the runway, and keep the aileron buried even if the wing comes up.

slowmover wrote:Fiddler, great post. I bookmarked your blog entry FWIW.

I have about 8000 TT, 2000 hours in Super Cubs and 180s, and it pains me to say that, at about the 1801 TW time mark, I looped my 180. Luckily no damage was done, except to my pride. It was "substantial damage."

I'm pretty careful and try to stay within the recommended crosswind limit that the manual states. I landed at my home field one day when the wind was gusty out of the northwest, about 70 degrees off the paved runway. I wasn't feeling particularly sharp that day but I was aware of the threat. And, there's no AWOS/ASOS on the airfield, so I didn't know exactly what the wind was. Somewhere in the 12-15 kt crosswind range. Best I can recall, and I wrote it down when it happened, is this: I made a conscious decision to land where I knew the wind was close to or out of the max recommendation. I touched down fine, and I buried the aileron. But then the downwind wing started to rise. I backed off the aileron, and then I started to ground loop. Full rudder and brake were to no avail at this point and around we went.

What's important in all this is to say what would I do next time. Next time I will (NTIW): look for a place more in line with the wind, angle across the runway, and keep the aileron buried even if the wing comes up.

I think this is really interesting, I have just passed 1000 hrs, all in my 170 and I try to think about every landing like I am just beginning. I know I have been way to relaxed at times, and felt overconfident. I sometimes try too hard to save what was a shitty setup, when I should just go around. A groundloop really can happen to anyone.

This Aileron to the stops is a good reminder.

I'm fortunate enough to get to fly a T-6. With that narrow main gear ailerons are a primary control during the takeoff run and up until you stop on the other side of the hold short line.
There is no relaxing but there is also no robotic holding it against the stops.

There is a downside to robotically going to the stop on the ailerons.

Doing so can excessively lighten the downwind wheel, and if you need that brake to stop a yaw, which is not uncommon in large x-winds, you might have sealed your fate. I’m certainly not immune, and have had one or two saves that required me to ease up on the ailerons to give the downwind tire some more bite.

A lot of years ago, I flew with a guy who had a lot of hours in a C-46. He taught me to "Drive it into the ditch",

It works, but like anything else, use it as applicable.

And, to pick a nit, I still frequently hear folks refer to maximum demonstrated crosswind as a limitation. It is NOT a limitation. It is precisely what the name suggests: It's the maximum crosswind component the test pilots encountered during the flight test for certification.....and in talking to a few folks who've held those jobs, they told me they didn't go looking for crosswinds.

MTV

I have a couple of questions.

1. How fast are you guys landing that you can still lift a wing after you are on the ground? And why are you landing that fast?

2. And why are you landing in a crosswind without having the aileron deflected already- and then you are deflecting it?

On my question number 1. Anytime I'm landing in a crosswind that is strong enough to either require a crab on approach to stay in line with the runway, or that is strong enough to push my airplane off the centerline on approach, I'm deflecting the aileron enough into the wind and with enough opposite rudder to keep the airplane going straight without any drift. And that means I'm touching down on one main wheel and a second later the other main wheel touches down because neither of the wings have enough lift to fly. And I've already got the aileron deflected as needed for the wind. As the airplane slows, and I'm not already full aileron I'll go there- but no way there is enough wind over the wings to cause one to lift.

If it's a gusty crosswind I'll carry just a little extra speed on final approach but again it's one wheel first and maybe two seconds later and the other wheel touches. Under neither condition is the outboard wheel "lifting" off the runway after its on the runway. That just seems incredibly dangerous to me- the plane is still flying and you are wheels on the ground with the power pulled. That is definitely a recipe for a ground loop or any other number of bad things.

On my question number 2. As an example shortly after I purchased my RSTOL 185 I was landing at King Salmon. The runway that lined up to the wind was closed for repaving with equipment on the runway. The other runway, the one I was landing on, had a 25knot 90 degree crosswind from the left and half of the runway (in width) was closed as it was torn up to be paved- so I had no opportunity to cheat the wind at all.

My first step was to identify an alternate field to land in case I couldn't maintain lineup on the runway, and that airport would be Naknek.

There were three of us on final. One aircraft in front of me landing and one aircraft behind me on approach. Had this not been the case I would have landed from the opposite direction so the wind was from my right. Reason is taildraggers with American made engines want to go left because of the direction of rotation of the propellor (Russian powered planes want to go right for the same reason) so in the case of a 90 degree crosswind I want the wind from the right so any application of power will help fight the weathervane the aircraft wants to do- rather than quicken it.

Anyway on very short final when I ceased crabbing and leaned into the wind to straighten the plane it took full aileron to hold my drift and I don't recall how much rudder to stay straight. One notch of flaps and I held the left wheel off till the airplane couldn't fly anymore, that wheel touched and the other immediately after. Aileron was already fully deflected as part of my approach so nothing to do there.

Taxiing down the runway to the turnoff did require some serious brake stabbing as without airflow over the rudder that big sail at the back of the 185 wanted to weathervane the plane. This 185 doesn't have a locking tailwheel but even with one in really strong crosswinds only the brakes will keep the plane taxiing straight, and even then I've been in winds strong enough that a 270 degree turn was required to make a 90 degree turn.

Don't do stuff because you've heard you should. Do whatever is necessary to fly the plane. And do it all the way to the hangar. (Like still deflecting ailerons and elevator in the appropriate direction while taxiing into/away from different winds. Easy way to remember while taxiing- climb into the wind, dive away from the wind. (Without actually causing the plane to start flying of course- I would hope that would be common sense)

Fun discussion. Thanks Fiddler.

Barnstormer said what I was thinking.

Last summer I went for a flight. Upon arriving home the winds were 24G37. Landed without issue but it did require full aileron and rudder. The fun part came when taxing to the hangar. Lots of brake was needed to keep straight then all at once the downwind brake failed at the rudder pedal sending me into a slow motion ground loop. I ended up taxing with my right foot on the passenger side left rudder pedal and my left foot on the pilot side right pedal. Had the brake failed earlier it wouldn’t have mattered much other than the ground loop would have occurred on the runway when the plane slowed down enough that the control surfaces were no longer effective enough to keep the plane straight.

I'll answer MTV and Barnstormer's comments because some of them are directed at least partially at me.

MTV, I totally agree with you that 12 knots in the 180 is a recommendation, not a limit. I treat it as a limit, but it isn't one. I know that the 180 will handle more than 12 knots. I also know that it gets challenging, and certainly on the day I described above I was not up to the challenge. You know that crosswinds in the teens are challenging too, because you once said that "fifteen knots is a no shit crosswind in a 180 or 185. And if there’s gusts, it can have hair all over it." That's a great quote, by the way!

On the day I described above, the wind at one nearby airfield was 60 degrees off at 10 gusting to 22. I did the math with runway headings and all that and the crosswind component was in the mid-teens and as much as 19 knots. Certainly outside my capability on that day, on pavement no less.

Which leads me to Barnstormer's comments. You're right in that I was carrying a few extra knots that day. 30 flap with a tail low wheel landing is typical for me. I usually touch down with the stall horn blaring, so maybe I could be a bit slower but not much. In a crosswind, I typically land with the aileron that I need to maintain the ground track and then add in the rest as I decelerate. This day had a gusty crosswind, mechanical turbulence over some hangars, and what might have been the perfect amount of aileron at one point was too much a few seconds later when the gust hit. Hope that answers your questions.

I'm not trying to pass the buck here. I own this one, have and will continue to learn from it, and hope others do the same.

Good point Barnstormer on speed. Speed is the greatest contributor to ground loop damage. Headwind component by definition should decrease our ground speed on touchdown. I have never understood the the need to use less than full flaps and certainly not the need to increase airspeed such that ground speed is greater. Throttle movement can manage gust spread and our normal approach will result in much safer touchdown ground speed.

In reference to the small single engine airplanes most of us fly, we need not look for strong crosswinds, they will find us. Flying a 3500 mile pipeline patrol loop weekly, I developed a technique that worked well and safely. Already using the apparent brisk walk rate of closure short final to touchdown on the numbers slowly and softly, I simply default angled across a bit in slight crosswind and a lot in strong crosswind.

If uncomfortable with default angle across, use rudder only to level the wing on final to immediately discover any slight crosswind. If we are directing our course with rudder only, the wing is automatically level. Centerline should be exactly between our legs. This will get the feet moving and tell us which wing should be lowered to cancel drift. Gusts may require dynamic reactive aileron movement to lock the angle of bank. While rudder is dynamic proactive, it is not coordinated with aileron in this side slip. While aileron is dynamic in gusts, we drive the yoke to the upwind ditch, as MTV says, on touchdown. Not to be confused with coordinated turns. The rudder has to be dynamic and proactive down the centerline.

Back to Fiddler's thesis, international or unintentional crab to touchdown and/or coordinated turns to realign with the centerline extended set the video ground loops up while quite feet and failure to increase aileron into the crosswind as they slowed down finished them.

The max demonstrated crosswind is a certification requirement, and is 1/3 of the stall speed in the landing configuration.

Check any POH and do the math. As MTV stated, it is not to be confused with actual capability.

Angling across I never ran out of rudder, even on 40 kts direct crosswind and never needed much runway. I occasionally landed with no ground roll. As Whee said, taxi was the problem with tailwheel, especially older models with cable activated mechanical brakes. Solutions were stop oriented into wind and wait, get assistance ground handling, or get the gas truck to parallel upwind.

There are some places where tailwheel and high wing are necessary. For an every day working beast in the weather given but workable, nose wheel was the best thing since beer in cans.

Having clocked up more than a few thousand hours over 40 odd years in our C180 (no I’m not ancient having just turned 60) I came as close as I‘d ever come to ground looping it recently. On the tarmac with a relatively benign crosswind on a hot day. I don’t realy know what happened but it all started to go pear shaped rather quickly and everything I did to get out of it was pure reactionary with out having time to think about any of it. I thought afterward “what the hell happened there”. I think I may have got caught in one of those summer whirly’s. I didn’t see it coming. It was a close call and made me realise “It can happen alright” and probably when you least expect it.

Barnstormer wrote:I have a couple of questions.

1. How fast are you guys landing that you can still lift a wing after you are on the ground? And why are you landing that fast?

2. And why are you landing in a crosswind without having the aileron deflected already- and then you are deflecting it?

Excellent thread! I really enjoyed the OP, and the comments have been very interesting and educational!

Barnstormer, two excellent questions. I think I might be able to offer some insight on both questions.

1) In my opinion, way too many pilots were trained to approach and land way too fast. Go to any busy airport, and watch the approach end of the runway for an hour or so. You'll see folks on angle to touch down at one point along the runway, then they start their flare and the airplane just sails along, just off the ground, until they are 300-500 feet down the runway before they make initial contact. During that 300-500 ft, the airplane is bobbing up and down (PIOs) as they work the elevator, trying to deal with the excess airspeed they are carrying. (But if you ask them about it, they will tell you they must have hit some gusty air just before touchdown.)

If you use the FAA's recommended pattern and approach speeds, a C172 with a Vso of 40 kts should be flown at 56 kts on base (1.4 x Vso), and 52 kts on final (1.3 x Vso). But even the Cessna manual recommends MUCH higher speed on final approach (61 kts for short-field landings). So that pilot who flies downwind at 90, base at 80, and final at 70 (very commonly heard numbers amongst C172 pilots) has a whole lot of energy to dissipate in the final 10 feet above the runway...

Flying that same airplane in the pattern, using a much tighter pattern than most current flight schools teach (so you're not having to drag it in on a long final approach leg, well behind the power curve), AND using the FAA-recommended speeds for base and final approaches would result in a LOT less energy to be dissipated. But logic dictates that you also have less margin for error... So I suspect that the flight schools – out of self-preservation, and making allowances for rookie pilots – teach faster and faster speeds. If you were taught the 90/80/70 speeds, and then encounter gusty winds, and add 1/2 the gust spread to those speeds, you could easily arrive in ground effect at nearly twice the stall speed... That's a lot of energy to dissipate in that last 10 feet!

As for Question 2: In some cases, the "crab and kick" final approach technique (versus side-slip for runway alignment) is responsible for the pilot not only having ZERO aileron deflection at the "kick" point, but also leaves the pilot ignorant of how much aileron will be required to maintain centerline alignment. I haven't seen the crab-and-kick technique used as much by experienced tailwheel pilots, but low-time tailwheel guys (like me) tend to revert to however they were first trained to perform crosswind landings (rule of primacy). If you got used to doing that in a C172 and then try to do the same in Stearman... Well, you might just go viral on YouTube.

In a tricycle-geared airplane like a C172, the crab-and-kick method may work well enough, assuming you time it right. But I cannot imagine it would work nearly as well in any tailwheel plane, much less something more challenging than the Citabria I learned in... Thankfully, my first CFI (way back in 1978) taught me the side-slip technique. We flew off a runway where howling crosswinds were the norm... By using the wing-low technique to maintain runway alignment on final, I think I developed a much better feel for the amount of aileron input that would be required in that plane on that day on short final. Of course, gusty winds or ground-feature turbulence will still need to be dealt with, but your "baseline" is already established.

Good discussion!

I agree this is a great thread.

JP256 makes me think a bit. I have flow conventional gear airplanes, the last one was in the '80's and I finished my training an a C140 and a citabria 7ECA.

My question is at what point do you transition into a side slip to land?

I go to cross control very shortly after establishing base, I fly close circuits all the time and my normal approach and landing I go to idle at the end of downwind and if needed correct with power along the path.

I find the most established final that way as there is no re-configuring the airplane from crab to side slip at short final, it is small corrections from the time the plane turns from final.

What do others do?