Wednesday, December 06, 2006

Fuselage Fit-up: Main Gear (cont.) and Tailwheel

I decided to final install the main wheels and brakes to the gear legs. This will make it more convenient to move around in the garage. When time to cover I can remove the gear simply by pulling the bolts holding the leg assemblies in the sockets. I used sacrificial bolts for now so I would not screw up the threads on the permanent bolts. I checked wheel alignment by clamping straight sections of angle to the brake rotors and they were dead-nuts parallel. So apparently the jig fabricated in the previous post was successful and tire wear should be minimal in the taxi position. According to Rans, a slight toe-in of wheels should occur on "wheel landings" which will enhance stability by pulling gear together as opposed to spreading. All that remains to do to the gear is hookup brake hydraulics later.



I then attempted to fit-up the tailwheel assembly. The tailspring is attached to the fuselage at three bolt locations: one forward and two aft. The latter two connections through three pillow straps, sandwiching the tailspring, to welded bushings on the fuselage. Upon inspection, I observed that the distance between the center of the welded bushings is much less (1/8") than the distance between the center of the holes on each pillow strap. Therefore, the holes were misaligned between welded bushings and pillow straps and bolts would not go through. I contacted Rans and they confirmed this is a common problem. Apparently, during welding operations the bead will cool and draw the bushing inward, resulting in the above discrepancy.

I decided to oversize drill the holes in the pillow straps from 3/16" to 1/4" in order to get the bolts to fit.