Take Time to Get Them Right
The alignment of thes items are pretty critical to performance. One has to consider that these surfaces are much larger than trim tabs and unless the are perfectly straight and parallel they are injecting control inputs on the flight of the airplane. The amount that the individual misalignment control inputs do not cancel out has to be corrected for by control inputs by the pilot (DRAG!). The amount that the misalignment control inputs do cancel out as far as the flight path of the airplane is concerned still have an effect on the performance of the airplane - DRAG!. I guess I'm the odd ball here from all of the "first flight" photos I see with naked legs, I didn't even consider flying my airplane until EVERY fairing was installed. I followed a precise procedure for the alignment of all the fairings provided by a fellow named Tracy Saylor (spelling?) with the main landing gear strut fairings bought from him - plane positioned level with respect to the canopy deck reference plane, plumb bob to points on the floor from front and rear of each item and the centerling of the fuselage. It isn't straight until all of the lines on the floor are parallel with the one for the fuselage centerline. I made my own intersection/interference fairings with modeling clay molding on the airplane and fiberglass layed up over it. I fiberglassed right on to the wheel fairings and cut them at the wheel fairing split after the first ply was layed up. I built up successive layers with the wheel fairing halfs separated. There is only one crack, no screws and it is incredibly smooth. A similar process was used for the upper main gear fairings but I cut them right down the trailing edge and down the inner surface inlign with the strut. I riveted an aluminum "tab" to the front and extended it back under the rear part enough to support two plate nuts. The larger piece is attached to the fuselage with flathead screws, dimple washers and plate nuts - three points - two at the front (inboard and outboard, one at the read outboard. The small piece is also attached at three points with the same hardware two points interface with the plate nuts on the tab from the big part on the inboard side and the third point is fastened to the fuselage on the inboard side of the fairing. the trailing edge is left open. The resulting cuff fairing comes off cleanly with no other disassembly. The upper nose strut to cowl fairing fiberglasss is built up in a similar maner but it is built up on two .032 aluminum plates. The split line on this fairing is down each side inlign with the nosegear strut. The front half attaches to the cowl with platenuts on a back up doubler plate, flat head screws and but no dimple washers (the aluminum plate itself is dimpled). The rear half is attached with three inline round head screws that attach it to a special aluminum support structure. The front screw is permanently screwed into the support structure and the fairing plate is "Keyholed" to fit on it. When it is slid to the forward position the two rear screws and washers are installed to lock it in place. This is definitly a creative part of the airplane and how you do it has a direct affect on performance - speed!
Oh yes, time - I don't even want to think about it - excellence should be the goal.
See you at Sun 'n Fun next week.
Bob Axsom
RV-6A, N710BJ
