Flaperon Rigging Question (Mk2)

[dholly]

This info might be of interest to you guys.

From Dec 1988 Kitfox Owner Newsletter, pg 2.

Some of our builders with the Model 2 have had problems with the FBK-5 aft aileron bell crank. The bushing was not properly located on some of them delivered over the last 4 months. If yours will not fit and pivot freely, send it back and we will send you another. If you have access to TIG or oxyacetylene welding equipment, you can grind away the excess material at the corner of the FBK-5 and re-weld it.

From Jan 1990 Kitfox Owner Newsletter, pg 3.

RIGGING DETAIL: on page CF-18 of your builders manual, step 69, it tells you to have the tops of the FBK-9 Individual Flaperon Bellcranks approximately parallel to the Mixer Bellcrank. Actually, on the Model 2 the inward ends of the FBK-9's when properly rigged will point down, possibly 15* degrees or more, with the flaperons leveled according to instructions.

MIXED UP BELLCRANK: About 25 FBK-7 Mixer Bellcranks were inadvertently built incorrectly, as a mirror image. Most of these incorrect bellcranks were shipped in November 1989. Please check to see if your Mixer Bellcrank looks like the one in diagram F-5 page F-6 of the builders manual. lf your bellcrank is not correct, please let us know and
return it for the correct bellcrank.

[Marshawk]

Thanks for the Post Dholly ,we were wondering why the rigging instructions wouldn't make sense. Our KF2 was manufactured in 1989 so I'm pretty sure we got the wrong bell crank.Does anyone know if the proper bellcrank is still available some were. If not has one made the incorrect one work

[Peteohms]

No as i have to push the stick right to fly with no roll i tried to find a method to check the correct setting of my flaperons.

So no answer and so same interrogation like you.

GDN,

I believe you have to adjust the struts to remove the roll. I used a digital level to adjust mine.

Pete

[akflyer]

Im with /\ . A rolling tendency will not be fixed by re-rigging the flaperons. The only thik that will accomplish is perhaps centering the stick if it is off to one side or the other in level flight. To fix the rolling issue, you must adjust the struts.

[GDN]

sure but i have to apply a strong force on stick to keep it centered in flight like when you have hard crosswind.

[akflyer]

sure but i have to apply a strong force on stick to keep it centered in flight like when you have hard crosswind.

The flaperons are going to seek level in the wind. The rolling issue is because the warp on the wings are not the same. One rod end should be adjustable on your lift strut. If you have to hold in Right stick (just like I had to) then shorten up the left rear heim joint on the lift strut. That is why they have the adjustable end on it. When I turned mine in 2 turns it took away the roll, and as an added bonus, I am now able to run my elevator trim in the neutral position and not at full up. I also gained a little in climb and a few MPH in cruise because the plane was not fighting itself to fly straight and level now. It is the first time in 2 yrs that I have been able to fly hands off without rolling to the left and diving.

One good test is to fold the wings. Are the flaperons and trailing edge lined up with each other? My left flaperon and trailing edge was about 3/4" higher than the right wing. By turning the heim joint in and mathcing up the trailing edges, it made a HUGE difference.

[Geowitz]

One good test is to fold the wings. Are the flaperons and trailing edge lined up with each other? My left flaperon and trailing edge was about 3/4" higher than the right wing. By turning the heim joint in and mathcing up the trailing edges, it made a HUGE difference.

Idealistically, yes, but this is not always true. Especially with older kitfoxes. When I rigged my wings I had them perfectly aligned in flying mode, but when folded they we 6 inches off . This was because of a warp in the fuse due to welding processes at the factory. The geometry of the wing and spar connection points was a bit off and as the wings folded the dihedral would change on each wing. I had to rack the fuse using several large binder straps to bring it back closer to square. It's still not perfect, but the tips are now within 1/2 inch or so when folded. They are perfectly aligned in flying mode.

[akflyer]

Idealistically, yes, but this is not always true. Especially with older kitfoxes. When I rigged my wings I had them perfectly aligned in flying mode, but when folded they we 6 inches off . This was because of a warp in the fuse due to welding processes at the factory. The geometry of the wing and spar connection points was a bit off and as the wings folded the dihedral would change on each wing. I had to rack the fuse using several large binder straps to bring it back closer to square. It's still not perfect, but the tips are now within 1/2 inch or so when folded. They are perfectly aligned in flying mode.

Look at it this way. If you have a left rolling tendency, and you fold the wings and the left trailing edge is higher than the right, then guess what.. Of course each plane may be different but you have to have a starting point. Without a starting point, why even bother rigging them to begin with, just bolt everything together and hope for the best on the first flight.

[Geowitz]

Sorry, didn't mean to come off as correcting you, but I have a lot of experience with the process and the geometry involved. Really, the correct starting point is to level the plane with the wings in flying position and measure the dihedral, sweep, and washout. Who said anything about not rigging them and hoping for the best? He needs to check it the right way. The height of the trailing edge when the wings are folded can be misleading for the reason I stated before as the difference in height doesn't necessarily mean one wing has more washout than the other, thus causing the roll. None of the rigging measurements has anything to do with how they look as they are folded. Idealistically, yes, it would correlate, but the best starting point again for this guy is to rig and measure it in flying mode.

[Jfquebec]

You are right Geowitz,that the best way to fly straight..that's what i do to,,
It have no logic to set dihedral ,sweep and washout and after folding the wing and remove all your measurement for a good look when it's fold.

Jf