flaperons

[Flybyjim]

Hi Guys,

I am ready to either install the weights on the flaperons but the next step is the linkage setup using the wood blocks for correct angles. It seems to me I should not put the weights on until after setting up the linkage as the weights could just get in the way. Am I missing something here or is there a reason to put the counter weights on first.

[Esser]

Going off memory I think I did the weights last but that was already a couple years ago (time flies) so I cant remember exactly.

[jiott]

No reason to put the weights on first-they will get in the way.

[efwd]

I just did it last month. Do them after. I had to re do the control arm after installing the weight and it is just in the way. Bad measuring on my part. So, Maybe Im the only one who has done it both ways.:(
Eddie

[Flybyjim]

What part of this build did you measure wrong, it does seem a bit critical in the set up. I hope to cut the wood blocks today and do the build tomorrow. Any insight from anyone would be helpful.

[jiott]

From my experience, the hardest part of holding that control arm measurement is when you drill the first hole. Your measurement can be very precise, but when you put pressure on the drill it seems to want to move. So my advice would be to have some way of securely holding the assembly during the drilling. Once that first hole is drilled and clecoed then the rest is no problem.

[jiott]

My control arm measurement ended up a little off for reasons stated below, but it seems to have no effect on the way it actually flies. So don't overstress yourselves on this.

[efwd]

Jim is exactly correct. That happened to me on the first one as well but I also had mine inserted too far. Had to weld four holes closed and new ones drilled. Honestly, after seeing where everything hooks up, my mistake would probably not have been a big deal.

[TahoeTim]

I recall that I predrilled the arms. If you follow the manual and block under the arm, it's not a big deal. I also felt that the whole process was intimidating but ended up being uneventful.

[efwd]

Tim is correct. You can, and should block beneath the arm but be sure to secure the arm down to the bench also. What happened was it lifted out of the shallow groove made to allow the arm to have the correct measurement.. It takes very little lift from the drilling to negate that minor groove you made.

[Flybyjim]

Thank you all for the encouragement on this step. I made the jigs today and that went well so this weekend I hope to get the linkage together. I restored an 1947 L16A over the past several years and there had been repairs done on this old bird over it's life. She is not square on the rigging, the wing attachment above the door is a bit lower than the other side but the plane flys well with a little trimming on the struts. As with most all of us we want our projects as perfect as we can make them, thanks for the responses. Every time I have asked a question on this site I have received valuable advice. I hope I can pay it forward as I learn the Kitfox build.

[Floog]

During the rigging process toward the end of the build, isn't any small misalignment or mismeasurement taken up with the angular adjustments of the push rod heim joints? At that point, I guess you're just ensuring both sides are equal and centered. In straight and level flight, I wondered what kind of 'load' was on the flaperons. I reached back over the seat to see if I could move the pushrods by 'twisting' them back and forth. I could do this quite easily, almost felt the same as on the ground not moving. It was a warm and fuzzy moment:)
The angles on those flaperon arms affect how the airplane rolls with respect to P factor, I believe. So if they were off a little, the roll wouldn't be balanced in the way it was designed.

[TahoeTim]

True, but the arms also seem to be crucial regarding the differential relationship between the left and right aileron and equal flaperon deployment. I watched the linkages with curiosity after I assembled it. I determined that I could not dial out the error in arm position to correct the change in differential or the flaperon angle. What does that mean? IMHO, if you are off on the arm placement then your plane will possibly bank quicker one way over the other which is no big deal at all. However, if your plane banks when you pull the flaps, that would be annoying to say the least. You can't adjust the rod ends to solve both "errors". When the time comes, I will probably go for no drift when pulling flaps.

Maybe the factory could confirm my theory?

[efwd]

Well Tim, I am glad I fixed mine then. Thanks for the post.
Eddie