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- Sep 7, 2009
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so, not being a fan of plain bushings with bolts just not tightend to pivot on i modified my idler bellcranks on my elevator system to use all bearings. the first one was easy, just increase the mounting tube size on the fuselage to allow 2 KP4 bearings to sit side by side in. no modificaion was needed to the bellcrank itself. the second idler required a complete redesign. length was kept the same as 4 inches between pivot points, but i installed a rod end at the top and built a bearing cage at the bottom. the tabs to mount to the fuselage remained the same as per plans so it could be a drop in modification.
The next thing i did, was redesign the first pushrod making threaded inserts for male aurora rod ends. these are the only 2 non ball bearing rod ends on the plane. the reason for this, is these 2 rod ends allow 18 degrees of rotation instead of the normal 10. this will allow the ailerons to deflect to the full 25 degrees. not 21 degrees that the plans reduced it to so the rod ends dont bottom out and back the nuts off. getting those 4 extra degrees of travel back should help out with the roll rate. i had to use male rod ends because they only had female ones with 1/4 28 threads, which is smaller than called out for in the plans. wasnt comfortable with going smaller, even though it may have been fine i didnt know. so, the male ones have a 3/8 24 thread and i just made threaded inserts for the pushrod similar to the end of the no.3 pushrod. i also bent the bottom of the stick and no.1 bellcrank out to allow the rod end to fully rotate before hitting the sides. 2 small spacers are installed on each side of the rod end. elevator control system is done and works great. dont have the wings fit to it just yet so cant tell on the stick travel for the ailerons but its going to be more than enough as it will it the sides of the fuselage before the rod ends bottom out......
The next thing i did, was redesign the first pushrod making threaded inserts for male aurora rod ends. these are the only 2 non ball bearing rod ends on the plane. the reason for this, is these 2 rod ends allow 18 degrees of rotation instead of the normal 10. this will allow the ailerons to deflect to the full 25 degrees. not 21 degrees that the plans reduced it to so the rod ends dont bottom out and back the nuts off. getting those 4 extra degrees of travel back should help out with the roll rate. i had to use male rod ends because they only had female ones with 1/4 28 threads, which is smaller than called out for in the plans. wasnt comfortable with going smaller, even though it may have been fine i didnt know. so, the male ones have a 3/8 24 thread and i just made threaded inserts for the pushrod similar to the end of the no.3 pushrod. i also bent the bottom of the stick and no.1 bellcrank out to allow the rod end to fully rotate before hitting the sides. 2 small spacers are installed on each side of the rod end. elevator control system is done and works great. dont have the wings fit to it just yet so cant tell on the stick travel for the ailerons but its going to be more than enough as it will it the sides of the fuselage before the rod ends bottom out......
