Saturday, September 22, 2012

Assembly Of Hinge Bearings & Trial Fit To Stabilator

Having machine countersunk the hinge brackets and primed the bare metal left by the countersinking process, plus priming the hinge bearing housings ... it was time to rivet the parts onto the aft bulkhead.
                                    Hinge brackets and hinge bearings ready to be riveted onto the aft bulkhead.

Thought it may be a good idea to set the hinge bearing rivets in two squeezing rounds in the hopes the bearing would be set with an evener pressure all around.  The rivets were first partially set using a crisscross pattern then final set using a crisscross pattern.
                                  Riveting the hinge bracket and hinge bearings onto the aft bulkhead assembly.
                                           Finished aft bulkhead assembly with hinge bearings riveted in place.

Once the hinge bearings and hinge brackets were successfully riveted onto the aft bulkhead, my friend Bernie happened to stop by. Perfect timing, Bernie was enlisted to help me lower the stabilator down from the ceiling so the aft bulkhead/bearing assembly could be trial fit to the stabilator.

Before riveting the bearings onto the aft bulkhead, a check was made to insure the brackets were 90 degrees to the aft bulkhead. (Of course, the brackets on the stabilator were also checked prior to riveting). The washers are really hard to get in place, so prior to test fitting I broke out the digital micrometer and measured the spacing of both brackets on the stabilator and they were exactly the same size. The reading was noted then the bearing width was measured and subtracted from the stabilator bracket width. Now I knew the total gap which would need to be taken up by the washers. Next the washers were measured and as it worked out, there was room for one thick washer and a half thick washer for each hinge bearing assembly.

Next the aft bulkhead assembly was held in place and the gap was eyeballed … it was determined the bearing gap was symmetrical on both the left and right hinges. Looking closely at the spacing, decided the thicker washers should go on the inboard sides of the bearings and the thin washers go on the outboard side of the bearings. With that configuration there was very little side to side play and no binding when moving the bulkhead/bearing assembly through its full range of motion. So final hinge washer positioning is:
Thin washer – left bearing – thick washer & thick washer – right bearing – thin washer.

Once the trial fit was completed, the stabilator was hoisted back up to the ceiling to resume its current role as DOG Aviation ceiling artwork until the RV-12 is ready for final assembly. The aft bulkhead was then Clecoed into position on the tail cone skins and the F-1280 left side skin was then Clecoed to the fuselage frames.
                                                     Aft bulkhead Clecoed in position on tail cone assembly.
                                                      F-1280 left skin set into position on tail cone assembly.