srhammett
Heliman
Location: near Seneca Rocks, West Virginia, USA
My Posts This: Topic Forum | I don't remember having this problem - not so much, anyway - on my original build, or when I've replaced the main gear before(once due to grass getting wound around the tail rotor, once due to a hard nose-down crash). It's a standard tail transmission, if that matters.
I was just taking off one day recently, heard a noise, and the tail spun out. I put it back down without difficulty.
I took it apart and saw that the tail transmission shaft (the short one that connects the delrin coupler and the pinion gear) had broken, up inside the coupler. It broke at a sharp angle, leaving some small, jagged pieces. No other visible damage, other than some teeth stripped off of the main gear. The delrin coupler was ok as far as I could tell. Even so, I've replaced it, along with the coupler pin and brass spacer.
That's the background. I'd welcome any ideas as to the cause of the shaft damage, but I realize it might have been vibration related, and no sermons are required on that subject, thanks!  . The immediate problem I have is too much backlash between the pinion and main gears. I can't seem to get rid of it.
I've flown it some since, but the main gear is already showing abnormal wear. (Time to order gear no. 5 %( !) Now, even if I remove the 3x35m screw through the main bearing block and loosen the other four screws holding the carriage, it just won't slide down far enough. I've oiled it where it contacts the side frames and bearing block so it moves up and down easily, but only for a distance of 1-2mm.
The cradle is so beefy, I can't imagine it being the culprit. The bearing block is in good shape. I haven't tried loosening and re-adjusting the main shaft to see if the gear can move a little higher, but it doesn't seem likely; there's no up or down play between the gear and shaft.
Something's blocking it, but it's really hard to see up in there.
Any ideas? Thanks!
Stu |
