Should I use opposite rudder?

[Bluebird19kf]

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?

[desertdave]

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.

[jiott]

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).

[Dave S]

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.

[SomeDay7]

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.

[109JB]

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.


https://youtu.be/zfwLglHEYvQ

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.

[Bluebird19kf]

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.

[Bluebird19kf]

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.

[Bluebird19kf]

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.

[Dave S]

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.

[HighWing]

Curious: Reading this thread, I can only find one hinted reference to aileron control - "stick". The Kitfox has a heavy history of owner pilots discovering that their wing tanks don't empty evenly. This contributed to the modification of adding fuel valves in the lines from the wing tanks. In my experience, the uneven fuel flow has been most likely due to the tendency for all of us to fly one wing low. Generally while following in our routine flights of 6 I found that the one wing low was very typical in the airplanes ahead of me and when flying in a flight of one, I find that not infrequently, my ball is not centered when in straight and "level" flight and then when checking on right wing to horizon and left wing to horizon i find that my left wing is low. In this case, stepping on the ball, will coordinate the apparent discrepancy, but the airplane will still be left wing low.

This phenomenon is far more common with the early models as the glare shield lacks the flat top used most commonly as a horizon reference, The only cockpit visible reference is the carry through above the windshield - typically above the bill of my cap. In short, I would suggest that if the ball is far to the right in a left turn, bank angle should be considered as well.

[Cobramatt]

I'll chime in with my experience. I have a Model 2 with a 582 and experience exactly the same effect. When turning base to final if I lead with rudder the ball starts sliding out and have to apply right rudder to get it back to center. Its a dance but with practice I have started finding the seat of your pants feel and can tell when i'm not coordinated. So right rudder in a left turn is common with My Model 2.

[109JB]

I still say it is due to adverse yaw.

When rolling into the turn (ailerons deflected), you need lots of rudder in the same direction of the turn to counteract that adverse yaw. Once you get to the bank angle you desire you neutralize the ailerons and the adverse has goes away, but the rudder is still displaced yielding too much rudder in the direction of the turn and the ball swings to the outside. At this point you don't need opposite rudder, you need less rudder in the turn direction.

[Av8r_Sed]

I'll chime in with my experience. I have a Model 2 with a 582 and experience exactly the same effect. When turning base to final if I lead with rudder the ball starts sliding out and have to apply right rudder to get it back to center. Its a dance but with practice I have started finding the seat of your pants feel and can tell when i'm not coordinated. So right rudder in a left turn is common with My Model 2.

Exactly describes my experience in my Model III as well.