Hi All,
Larry, AKA Wirejock, suggested I post the following as some guidance around how to remove the main longeron should you need to tweak it a little so that you can accurately match the "sharp downward bend". It is written for the RV-7 but may be applicable to any of the tail wheel versions, and of course may be an old-hat procedure to many. I checked in with Van's regarding how closely the longeron should follow the F-770 forward side skin forward of the sharp downward bend, and Scott Risan said that 1/32" was quite adequate. Anyway, I went ahead and began drilling mine from the tail forward per the instructions, and when I got to the "sharp downward bend", it was now off by 1/16"!!! I was drilling then 100% clecoing, and I suspect that holding it tighter to the skin resulted in the downward bend now being observed as inadequate. Thus, I had to remove and rework. Working alone and with no one to help me pull it all apart and flip the canoe over so that I could extract the longerons, I was at a loss as how to get these things out, and the VAF forums and builders websites I checked were turning up no hints. I figured I couldn't pull them out in situ, as there was so much load on the sides and nothing else supporting them. After blankly gazing at the structure for what seemed like an eternity, I came to the conclusion that if I supported the structure on one side at the F-704 bulkhead and picked up the tail using the tailwheel spring, then I should be able to pull them out one at a time by myself. I cut a piece of 4x2 and wedged it between the seat floor at F-704 and the top of my sawhorse (aka a table with adjustable threaded rods drilled into the legs for leveling purposes) making sure that it fit flush against the seat floor so that there was no risk of bending the flanges on the F-704 or the seat floor itself. This lifted the forward left side about 2", then I picked up the tail and placed it on my tall sanding table. It is only necessary to lift enough to get the longeron out, as any more than is necessary places undue stress on the opposite side of the main bulkhead. I then unclecoed the fuselage at the F-706/7/8/11/12 bulkheads up to the upper fuselage J stiffener, and with everything else intact on the other side, the fuselage remained perfectly stiff. The longeron was then removed from the forward end working aft, and in all, it was as easy as pie to get out. Re installation is of course the opposite of the installation, starting at the "notch" at the aft of the fuselage, and working your way forward. I hope this helps you reach the level of perfection you desire on your longerons!
Tom.
Larry, AKA Wirejock, suggested I post the following as some guidance around how to remove the main longeron should you need to tweak it a little so that you can accurately match the "sharp downward bend". It is written for the RV-7 but may be applicable to any of the tail wheel versions, and of course may be an old-hat procedure to many. I checked in with Van's regarding how closely the longeron should follow the F-770 forward side skin forward of the sharp downward bend, and Scott Risan said that 1/32" was quite adequate. Anyway, I went ahead and began drilling mine from the tail forward per the instructions, and when I got to the "sharp downward bend", it was now off by 1/16"!!! I was drilling then 100% clecoing, and I suspect that holding it tighter to the skin resulted in the downward bend now being observed as inadequate. Thus, I had to remove and rework. Working alone and with no one to help me pull it all apart and flip the canoe over so that I could extract the longerons, I was at a loss as how to get these things out, and the VAF forums and builders websites I checked were turning up no hints. I figured I couldn't pull them out in situ, as there was so much load on the sides and nothing else supporting them. After blankly gazing at the structure for what seemed like an eternity, I came to the conclusion that if I supported the structure on one side at the F-704 bulkhead and picked up the tail using the tailwheel spring, then I should be able to pull them out one at a time by myself. I cut a piece of 4x2 and wedged it between the seat floor at F-704 and the top of my sawhorse (aka a table with adjustable threaded rods drilled into the legs for leveling purposes) making sure that it fit flush against the seat floor so that there was no risk of bending the flanges on the F-704 or the seat floor itself. This lifted the forward left side about 2", then I picked up the tail and placed it on my tall sanding table. It is only necessary to lift enough to get the longeron out, as any more than is necessary places undue stress on the opposite side of the main bulkhead. I then unclecoed the fuselage at the F-706/7/8/11/12 bulkheads up to the upper fuselage J stiffener, and with everything else intact on the other side, the fuselage remained perfectly stiff. The longeron was then removed from the forward end working aft, and in all, it was as easy as pie to get out. Re installation is of course the opposite of the installation, starting at the "notch" at the aft of the fuselage, and working your way forward. I hope this helps you reach the level of perfection you desire on your longerons!
Tom.
