Heavy aileron feel?

[Greensuiter86]

Hey folks, I'm band new to the group and recently acquired an absolutely beautiful KF II/582 from Roger Circle in northern Indianna. He won top awards at Oshkosh, S & F, and the Dayton Airshow with his plane, I trust his craftsmanship and attention to detail. The plane has 620TT(ish), and 80(ish) on the 582, and I had an A&P do a proper pre-buy on it so everything checked out. My question is this: I've flown RANS taildraggers and a Skyraider II and they felt very light and nimble on the aileron control. The KF is two fingers near the center at cruise, but the stick force gets what I feel is very heavy when you roll in and roll out to the outside of the stick movement. On the ground everything is free and clear, so I'm assuming it's aerodynamic pressure I'm feeling. The plane trims hands-off and is very stable in all axis. Can anyone shed some light? Is this "normal feel" for this model, or should I be checking something? It does have balance weights instanstalled and the rivet AD at the hinge points as well. Thanks in advance for any guidance/advice

[Av8r_Sed]

That's not my experience on my Model III. Initially I had some control linkage issues creating less than smooth operation on the ground, but I worked them out with spacer washers and adjustment of the rod ends. Also, too much flap deployment can limit travel and lead to some binding.

In the air, everything is smooth with a very light touch.

You might try jacking the plane at the strut attach points and see if the flaperon bearing tighten up with some wing flex.

[Greensuiter86]

Thanks AV8r, I may explore that. I just got off the phone with a KF IV owner and he said he experienced the same feel and thinks it is inherent to the design (full span flaperon in clean air). It may be that I'm not at true aerodynamic "zero" on the flap handle either since there is no detent to hit? I think jacking the wings up sounds like a good test for binding and for process of elimination.

[Peteohms]

Check to see that the flaps are not slightly reflexed.

[Av8r3400]

Check the rigging.

If the flapperons are reflexed too far (trim nose up) the aileron feel become very heavy. If a bunch of nose up is required, maybe the horizontal stabilizer can be adjusted to take out some of the pressure.

I've also had the seat pan rubbing on the aileron control rod going from the torque tube to the mixer. This made for very heavy controls...

[Greensuiter86]

Thanks for the advice. I checked the seat pan and we are all good there. I took the plane up this evening and noted the ailerons were actually reflexed down for trimmed flight with no stick pressure. When I adjusted them to what appeared to be level in flight the feel was very light and responsive but had to hold some back pressure. Going to check W&B for a slightly nose heavy condition but I suspect it isn't much. I've heard about an electric elevator trim, will that work for the KF II model?

[Greensuiter86]

BTW, you nailed it AV8r...thanks!

[Spook712]

How do I check for that, I might have the same issue.

Can I measure anything on the ground?

[jiott]

Yes you can check it on the ground. It usually involves jacking up the tail to level flight attitude and then leveling the flaperons using a wood block cut to clamp around the flaperons. Its all in the construction manual.

[t j]

Spook, for a quick check on a model 4 if you don't have the flaperon rigging blocks:
Take a grease pencil and mark the cord line of the flaperon on the metal inboard flaperon rib. Level the plane to flying attitude and the flaperon cord line should be level for neutral flaperon position. Be sure the stick is centered for neutral ailerons.

Note, for the earlier kitfoxes with the flat bottom flaperons, the bottom of the flaperon should be level.

[Greensuiter86]

Just an update to my initial post. I've learned to leave the flap handle alone and leave the flaperons at zero incidence. As the CG checked out fine, I went with lowering the horizontal stab leading edge to the bottom hole which eliminated the need for corrective negative flaperon trim. All is good with 627C. I've also finally learned to side slip almost to touch down and land on the mains and use brake to stop in a pleasingly short distance. Finally able to take off and land on my strip and put her to bed in my hangar. Now if I could just get it to be a bit more yaw stable it would be perfect!-)

Jay P
N627C