I started working on the assembly of my flaperons, ss7. I measured the distance between the most outboard hinge and the most inboard hinge on the flaperon. then I measured the distance between ribs #1 & #9. I need to bring my inboard hinge on the flaperon inward 1/2". I suppose this discrepancy is due to the discresionary placement of the #1 rib. does anyone see a problem with cutting off 1/2" of the inboard edge of the flaperon (not spar) and moving the flaperon end rib and hinge inward?
thanks, ken
Ken,
If you measured between the hinge tabs, you should measure between the mid points of the respective ribs as the hinge tab will bisect the rib width. Before cutting, I would have someone help you position the flaperons and actually see where the tabs are relative to the center of the ribs.
I don't understand your comment regarding the discretionary placement of rib #1. My understanding is that all wing ribs are positioned by design and the butt rib is the discretionary one and is positioned after wing rigging to close the gap between the #1 rib and the fuselage (skylight).
I agree that you should find someone to help you mount the flaperons on to the wing ribs. We had some very minor left/right centering of the hinges on the ribs 1/16" to <1/8" and absolutely no triming was required. Here is an image of Rib#1 adjacent to the butt rib and inboard flaperon hinge Cleco'd in place.
thanks for the responses. I looked back through the manual and found that the figure for installing the #1 rib shows a distance of 35.5" between rib 1 and 3, and I have 35". oops! john I will be calling you.
ken
Ken,
Your explanation clarifies the problem. In the past, it was not unheard of that factory built wings would arrive with one or more ribs slightly out of true. Those builders removed the hysol or in the old days, the 3M "Structural Adhesive" using a heat gun and a plastic scraper, Then repositioned and reglued the rib(s) in the correct location (or alignment). I think this would be much simpler than cutting the flaperon. I think there are threads related to removing the Hysol.
Ive taken off hysol on one of my tail formers. Heat gun, a little patience, and a screw driver will get it to come off in chunks...it doesn't come perfectly off though so it will look a little bad.
I don't think removing the hysol is easier in this case, because my butt ribs are already installed. removing 1/2" of aluminum sheet shouldn't be very difficult. but i'll wait till I talk to john.
I am curious regarding John's advice, but now understanding the issue, I would suggest using a dremel with a cut off wheel for the cut. You can make the cut slightly over size and then sand or file. Using snips would, in my experience, make waves in the aluminum along the cut lines. You will also need some foam to close out the open end. If you will be using the Hysol to install the faom, craft store foam would work. All doable.
Then the other thought, is the #1 rib the only one affected by the alignment discrepency?
I believe the metal end rib that is riveted to the flaperon skin(that the spar and control horn shaft pass through) would actually close this out, correct?
Sounds like a slight trim of the flaperon would be easiest and unnoticeable to even the typical Kitfox builder as all other measurements would remain the same with the control horns.
flaperon hinges
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