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Thread: Should I use opposite rudder?

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    Bluebird19kf's Avatar
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    Default Should I use opposite rudder?

    So I have flown 2 different Kitfox 2's one with a 582 and one with a 912. Something I don't understand is at times while turning (let's say left) the ball will be out to the right. I was not putting in a lot of left rudder either. I was hesitant to put in right rudder to center the ball in a left turn. Has anyone ever experienced this? Why does this happen? Is it correct/safe to use opposite rudder sometimes?

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    Super Moderator desertdave's Avatar
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    Default Re: Should I use opposite rudder?

    For starters, if you are cruising feet flat on the floor, where is the ball? If it isn’t centered you need to rerig the rudder or add a trim tab.
    Dave
    KitFox 6 Taildragger
    912 ULS
    Whirlwind 70” Prop
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    All around nice guy

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    Senior Member jiott's Avatar
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    Default Re: Should I use opposite rudder?

    I can't speak about the Kitfox 2, but my SS7 will do exactly what you describe in a gentle left turn. VERY little or no left rudder is needed because the inherent left turn tendencies of the airplane provide nearly all the left yaw you need. As the turn steepens and becomes more aggressive more and more left rudder is needed, but never as much as is needed in a right turn. Like you, occasionally I find I have put in too much left rudder and the ball is on the right; I just correct with some right rudder to get the ball back on center. Don't be afraid of opposite rudder, that's what it is there for-to enable you to fly coordinated. Just to ease your mind, too much opposite rudder (slip) is FAR less dangerous in causing a stall/spin than using too much rudder in the direction of the turn (skid).
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

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    Senior Member Dave S's Avatar
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    Default Re: Should I use opposite rudder?

    Easy Peasy - assuming the airplane is correctly rigged

    Other than when you are doing a slip - if the ball is not in its cage - step on the ball

    How much? whatever it takes to put the ball in the cage

    For sure a different amount of rudder is needed for a right vs a left coordinated turn and a different amount to initiate a turn as opposed to maintaining a constant bank.

    I put a trim tab on the rudder and set it for straight and level cruise power - got tired of constantly holding a little rudder on a trip. Nice thing to have.

    I neglected to mention - if the ball is centered - it's coordinated and that is safe - not centering it is where the gotchas live.
    Last edited by Dave S; 02-12-2020 at 02:07 PM.
    Dave S
    Kitfox 7 Trigear (Flying since 2009)
    912ULS Warp Drive

    St Paul, MN

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    Default Re: Should I use opposite rudder?

    In the Kitfox pilot's guide page 16 it states: Like the Model 1, the model 2 is yaw neutral and needs to have the nose "placed" where it needs to be.
    Starfox

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    Senior Member 109JB's Avatar
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    Default Re: Should I use opposite rudder?

    Quote Originally Posted by Bluebird19kf View Post
    So I have flown 2 different Kitfox 2's one with a 582 and one with a 912. Something I don't understand is at times while turning (let's say left) the ball will be out to the right. I was not putting in a lot of left rudder either. I was hesitant to put in right rudder to center the ball in a left turn. Has anyone ever experienced this? Why does this happen? Is it correct/safe to use opposite rudder sometimes?
    What you are describing with a left turn and the ball swung to the right is describing a skidding turn. A skidding turn is very dangerous and will put you upside down if you stall. A skidding turn is what causes base to final spins. Watch this video because it is a very serious thing.



    If the ball is not centered you step on it! Period! No ifs ands or buts. It doesn't matter what you think, or how much lead in rudder you think you used, the ball is telling you the airplane is not coordinated.

    Why does it happen? Many reason. Adverse Yaw which early kitfoxes are notorious for. Inadequate vertical tail area, which early Kitfoxes are notorious for. Also because of the adverse yaw you will need more rudder when rolling into the turn than will be required once the bank angle is established.
    John Brannen
    Morris, IL
    Sonerai IIL (Single Seat)
    Kitfox 3/4 1050 - Rotax 582 (Back Flying and sold)
    Kitfox IV 1050 - Rotax 582 (sold)
    Kitfox IV 1200 Speedster - Rotax 912 UL (project)
    Piper Twin Comanche (Sold)
    Glasair 1 FT (Waiting to start)

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    Bluebird19kf's Avatar
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    Default Re: Should I use opposite rudder?

    I hear your guys about being coordinated for sure. I’m not a newbie on skids and slips. The airplanes I flew did not fly uncoordinated in level flight and I did not apply to much inside rudder initially and not bring it back because I don’t understand the neutral rudder characteristics of these airplanes vs a Cessna that always comes back to center. I’m saying your flying level and coordinated and push the stick left and the ball is telling me to step on right rudder. That’s why I’m confused. I’ve experienced it in a 2 stroke which is counter rotating and the 4 stroke normal rotating engines. I’ve even been flying with someone else as a passenger who is an airline pilot and asked, hey why is the ball saying opposite rudder. All I get is I don’t know.

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    Bluebird19kf's Avatar
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    Default Re: Should I use opposite rudder?

    Also the adverse yaw thing is opposite of what I’m describing. Adverse yaw with no rudder input the ball would indicate I need to apply rudder in the direction of the turn because of the outside wing which is producing more lift and therefore more drag making the nose want to swing out opposite of turn.

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    Bluebird19kf's Avatar
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    Default Re: Should I use opposite rudder?

    Is there any way this could have to do with a tailwind? I’ve always been told that the airplane doesn’t care about the wind because it’s in the “air mass”. Basically saying the airplane would respond the same way in 200 mph steady winds as it would in no winds if you didn’t care about your relationship to the ground.

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    Senior Member Dave S's Avatar
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    Default Re: Should I use opposite rudder?

    Bluebird,

    Don't know if this will help at all or not - one of the experiences I have had with kitfoxes has to do with some subtle differences between the slab tail and airfoiled tail (IVs and 7s). I haven't flown every example in the fleet so my observations are obviously from a limited sampling perspective.

    I flew an 7 with the slab tail and discovered that the rudder had an apparent dead spot where it would not return to centered precisely but took a little rudder input to bring it back - after any rudder use. This was a demo flight and the salesman said that is a characteristic of slab tail. Not a problem - just part of the design. My wild elbow guess is this has to do with the way the air flows around a non-airfoiled surface.

    So I ordered the airfoiled tail for our build.

    The S7 I fly has the airfoiled tail and does not exhibit this characteristic.There are quite a few variants out there, however, I have observed that the earlier kitfoxes pretty much use the slab tail and the airfoiled tail did not come into general use till the S5 & later.

    May or may not be helpful, but wanted to share in case this is in any way useful.

    Then there is the deal with the springs and cables - with an open cable design and springs to balance - any difference in the spring tension or cable friction from one side to another is bound to have some residual effect.
    Dave S
    Kitfox 7 Trigear (Flying since 2009)
    912ULS Warp Drive

    St Paul, MN

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