Jigs
I built a "drill your own" RV6 which required an "H" jig which was used to build the tail and then used for the wing jig. After the tail was complete I built a second wood "H" jig, making one for each wing. ON the first I spent big $$$ on clear redwood 4X4's but the second I just screwed two pine or fir 2x4's together. Steel angle iron brackets bolted to the posts supported the main and aft spars which were "C" clamped in place.
Then very small diameter holes were drilled at the root and tip through the middle of the main spar as well as the aft spar. The locations of these holes were specified in the plans if I recall but they were very carefully located and mine were much smaller than a #40. Two plumb bobs on fish line were then suspended through these holes aligning both spars. I even had crosshairs drawn at each hole as well as one the shop floor for each plumb bob. Every day as I started work I checked the plumb bobs and the crosshairs. I don't believe I ever had to adjust the clamps but I may have. The 6 wings turned out in perfect alignment with 1 degree difference when hung on the fuse.
Now I have just complete a prepunched set of RV8 wings (not only am I a repeat offender, I stutter as well, since between the two I rebuilt wrecked RV4!) and I used the same wooden jigs. No plumb bobs on the PP RV8. Just placed the main spars to the top and clecoed it all together with the ribs just like Van's manual, riveted with the aft spar, clamped the whole works to the "H" jig in the normalized position. Added the leading edge and Tanks making the whole assembly pretty stiff and after riveting one skin on the wing was really stiff. After the second top skin was riveted I slowly released the clamps after marking the spar locations and the spars did not move even .010"! I will have to drive my car over them to make them twist at this point and the bottom skins are not even on yet!
Steel jigs? Not needed but stable wood would be nice if you are going to use an "H" jig. Maybe a piece of plywood glued between two 2x4's with sheet rock screws very foot or so. You really don't need the jig for that long before the wing becomes stiff so don't go through the trouble. But, if you clamped the wing parts in under stress or crooked I believe you would end up with very stiff, rigid but crooked wings. Who knows maybe my RV8 will do a slow roll on first flight because I did not use the plumb bobs!!
BTW I thought Van's now only requires a flat table to build wings. My wings were from an orphan kit from 2001 and the manual still showed a rough "H" jig which actually makes a very nice work station. The wings are now on a table to do the last sheet and now that I have done some work I wish I would have left them in the jig as I feel it is easier to work on them there.
Dick DeCramer
RV6 N500DD Flying
RV8 Fuse kit on hand.
Northfield, MN
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