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Aileron to Rudder Mix

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  • Aileron to Rudder Mix

    Just wondering ... does everyone use aileron-rudder mix for coordinated flying? I had it set to "ON" rather than assigning it to a switch. I found that my takeoff & landing rolls were way to squirrely due to rudder input added to the tail-wheel or nosewheel. I have now moved it to a switch and I keep the switch in the off position for takeoff intending to turn it on when airborne but I always forget to turn it on. Therefore my whole flight is un-coordinated. But at least I solved my squirreliness problem.

  • #2
    Hey there Pilotguy, which plane are you talking about? I was confused when you said you "set it to ON". It sounds like you have a gyro or flight controller onboard?

    In general, for most planes I fly (without gyro or flight controllers), I almost always coordinate rudder, especially tail dragger warbirds. But flying rudder is definitely not universal for all pilots. I've noticed many EDF pilots don't fly rudder, preferring instead to "crank and bank" with the right stick controlling the flying surfaces exclusively (Aileron and Elevator on a Mode 2 radio). EDFs can often be flown that way without huge detriment. But on the other hand, tail dragger warbirds and often large multi engine prop planes (B-24, C-130) will benefit from coordinated rudder input during certain maneuvers. It's just aerodynamics.
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    • #3
      Originally posted by Pilotguy View Post
      Just wondering ... does everyone use aileron-rudder mix for coordinated flying? I had it set to "ON" rather than assigning it to a switch. I found that my takeoff & landing rolls were way to squirrely due to rudder input added to the tail-wheel or nosewheel. I have now moved it to a switch and I keep the switch in the off position for takeoff intending to turn it on when airborne but I always forget to turn it on. Therefore my whole flight is un-coordinated. But at least I solved my squirreliness problem.
      Hi Pilotguy. If you have the rudder/aileron mix on all the time you should find that (on most radios) input from the rudder stick will still effect the rudder only, so left stick input to correct torque on take off (you are doing that aren't you? :Cool:) won't have too much effect on the roll axis.
      If however, you try to steer the model on the ground by using the mix to allow you to do it using the aileron stick then you certainly will find that the model is "squirrely".
      As Alpha said, coordinating the rudder will help a great deal on many models and the degree of aileron/rudder coordination will vary depending on many factors including model type, airspeed, flight attitude etc etc. and the best way to do this is to simply try it by flying a couple of mistakes higher than usual. Add a small amount of rudder with the ailerons when you start a turn and watch the result. If the tail seems to hang low, increase the rudder and vice-versa. You can still do this with the mix switched in of course.
      Where a dedicated rudder/aileron mix is very useful is on models with high aspect ratio (long, thin) wings and scale biplanes. Here you will find that it often eases the workload and makes flying a lot more pleasant that always adding rudder. It's also great for gliders where coordinated turns make a huge difference to efficient flying and therefore duration.
      My advice would be to keep using the mix for general flying, but try getting your rudder thumb into training too... you'll find after a while that you actually miss not having a rudder if you fly a model without!

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      • #4
        I have a mix set for a couple of my larger prop planes on a two position switch (on/off) but not on any of my EDF's or smaller planes. On planes like the Carbon Z C-150 lot's of rudder input is needed for a nice coordinated turn so I have a bit of mix just to lessen the workload a bit. Too much mix in a plane that doesn't need it (some EDF's) could potentially get you in trouble so I prefer to just use the stick to input what I feel is or isn't needed. Fly the plane for a while without to learn what that particular plane requires in regards to aileron-rudder mixing would be my advice. As long as you are able to turn the mix on and off, experiment with different percentages to find the sweet spot.

        Hope this helps!

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        • #5
          Its the 850mm Pitts that is most squirrely on takeoff/landing rollouts and its most noticeable with x-winds when I aileron input into the wind and wiith the aileron-rudder mix.

          When I said "set it to ON", I meant that the mix is active whenever the battery is connected & the airplane is bound to the X-mttr. As opposed to putting it on a 2-position switch. No onboard controller.

          Good point about getting "my rudder thumb into training".

          I think I just need to add "aileron-rudder mix switch off position" to my mental landing checklist. Maybe something like:

          -call out "landing" so others know I'm setting up for landing
          -approach flaps
          -gear down
          -landing flaps
          - flip aileron-rudder mix switch to off

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          • #6
            I'd recommend only mixing aileron to rudder to defeat any adverse yaw tendencies an airplane might have. Rudder is an underutilized control surface ;)

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            • #7
              Originally posted by andrew_flyguy View Post
              I'd recommend only mixing aileron to rudder to defeat any adverse yaw tendencies an airplane might have. Rudder is an underutilized control surface ;)
              Absolutely it is, i feel the difference drastically between use of rudder in a turn vs no rudder.

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              • #8
                Good rudder skills makes a good pilot

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                • #9
                  I would be very cautious with using a mix during critical flight phases such as take-off and landing. Just my opinion but I prefer to be in full control of all surfaces at these times. Mother Nature sometimes likes to throw us weird winds and such to keep us on our toes and sometimes even a small amount of rudder can get you into trouble on a small plane like that (or any plane in the right conditions).

                  Is the problem on the initial roll when the tail wheel is still on the ground or after the tail comes up? A lot of pilots (including myself) have a difficult time controlling or over-controlling tail draggers on the ground due to not anticipating the pull that's inherent to most (all?) tail draggers on the ground. There's a very fine line or a dance between the rudder and throttle input. The only way to learn what that plane requires is to dedicate some time on the runway experimenting with it. Each plane has it's own quirks on the ground. My FW P-51 is a completely different plane on the ground when I switch between a scale 4 blade prop to a large 2 blade. My old FMS Yak 54 was easier than some of my tricycle gear planes on the ground. But it took a battery or two dedicated to learning what they wanted (still learning on the P-51 with the 2 blade!)

                  Again, just my thoughts. Hope it helps!

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                  • #10
                    Practice makes perfect? It is improving now that I have about 8 takeoffs & landings under my belt. For the landings I think the advice that I’ve read many times on Hobbysquawk is appropriate and will help but comes with practice also. That advice is to fly her to the ground with some speed (like we do with warbirds). I do keep some throttle till main wheel touchdown(I don’t know but will guess 15-20% throttle until say 5 feet over the runway but then I bring it back to just a tad more but then she bounces off the mains (or 1 main in some cases) and starts banking and that’s when the squirrelyness really kicks in. But even my landings are improving with practice. But I think if I can fine tune the airspeed/throttle management on landings, I will really solve my squirrelly problem.

                    The aileron-rudder mix was definitely contributing to my steering control on takeoff and landing rolls and I agree about being cautious about having that mix ON for critical flight phases. . I have placed this mix on a 2 position switch now and I make sure the switch is off for takeoff. Trouble is I always forget to flip it on after takeoff so I can get that coordinated flight without manually inputting rudder whenever I bank the airplane. It’s not really “trouble” because I do not have a fine enough eye to notice any adverse flight behavior when it banks with aileron only. I am only saying that aileron input aerodynamically needs to be accompanied by rudder input. You can achieve that rudder input either manually by moving the rudder stick or by coupling it to the ailerons by mixing (full scale flying calls it “rudder damper”.

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                    • #11
                      The dreaded "PMP". As much as we hate to admit it, it does hold true. Glad you got some of it figured out though! It's easy to assume that once the mains are set that it's safe to dump the throttle and the flights over. The rudder has so much more influence on a tail dragger on those critical phases and if you fly a lot of tricycle gear planes it's easy to forget sometimes.

                      What stands true for the full size aircraft doesn't always work in RC as i'm sure you know. I'm willing to bet that what I perceive as a nice turn from the ground would be proven quite wrong with a turn coordinator. In the real thing we have the luxury of instruments, horizon line of site, and "seat of the pants" to tell us how good/bad we are doing. I will never forget the first time I sat in the left seat of an LC-130 and was given the chance to dodge some clouds. Up until then I had maybe 10 hours in 172's. I started to bank left, pull a touch and coordinate a little left rudder and watched as the VSI dropped like a rock! That was my first lesson in how different aircraft in varying phases of flight need specific inputs. (tried flying it like the 172)

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                      • #12
                        The old band director at the school use to work for would tell his students practice doesnt make perfect, perfect practice makes perfect. Basically what he meant was don't keep practicing bad habits, but when you make mistakes correct them then keep practicing the corrections until you completely clear them up. Then practice the perfected routines.

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                        • #13
                          Most airplanes will experience "adverse yaw" when banking due to the downward moving aileron creating drag along with lift in order to raise that wing and lower the opposite wing. All full scale pilots have received this very basic fundamental training.

                          Since I am not getting a first person view nor does my transmitter have a "turn coordinator" I just know from aerodynamics that there will be adverse yaw every time I input aileron and therefore need rudder input with every aileron input. I prefer to do this with mix rather than manually and the proper amount of mix will be a guess. I've been using 15-20% rudder for the mix.

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                          • #14
                            Pilots live by checklists and excellent flying judgement. I just need to get that landing checklist into memory. As I have said,
                            -mix off when on base leg or after I extend landing flaps.

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                            • #15
                              I use aileron/rudder mix most of the time on my scale electric models. I use a fair amount of rudder on my Sig 1/6 Cub to counter adverse yaw and bring the tail around in turns. Ailerons are not very effective at landing and takeoff speeds but rudder is effective for steering/countering torque during takeoff and for leveling wings during landings. High wing tail draggers seem to need more rudder input than warbirds to counter adverse yaw. Use of aileron/rudder mix is habit forming. If you accidentally switch it off, you may be alarmed at sloppiness or possible loss of control due to adverse yaw making turns or sudden need to use rudder stick while model yaws to the left during takeoff. Aileron/rudder mix may interfere with some aerobatic maneuvers. It is probably best to abstain from aileron/rudder mix and rely on continuous manual rudder and aileron inputs but I'm somewhat lazy.
                              Last edited by E-Challenged; Feb 10, 2019, 09:26 AM. Reason: I am not a "student pilot" but I am still E-Chhallenged, I just started posting on HQ

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                              • #16
                                High wing tail-draggers tend to have flat bottom to semi-symmetric airfoils and the airfoils have more effect on adverse yaw than if its high wing or low wing. An under-chambered airfoil is asking for adverse yaw.

                                I typically use mild (5% to 10% less down than up) differential aileron with symmetric airfoils, going to extreme (0 downward movement) with a deeply under-chambered airfoil.

                                You may not completely eliminate the need for rudder to do a coordinated turn using differential ailerons, but you can make it be so little that only people who practice Pattern competition aerobatics notice when you don't bother to touch the rudder stick.
                                FF gliders and rubber power since 1966, CL 1970-1990, RC since 1975.

                                current planes from 1/2 oz to 22 lbs

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