GRAUPNER Skalar, Manual

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elektro
Skalar
11
1.4 Assembling the main gearbox
(bag SKA-1)
Fix the tail rotor drive unit, the layshaft and the main rotor shaft bearing holders between the
mechanics side frames 44750.9 and 44750.10 using M3 x 16 socket-head cap screws, but don’t
tighten the screws fully at this stage. Fit a shim washer 4450.40 and the dome bearing holder
onto the main rotor shaft from the underside. Working from above, pass the main rotor shaft
through the bottom rotor shaft bearing and the ring gear 4450.20A to the point where the dowel
pin 4450.37 can be fitted through the cross-hole at the bottom end of the main rotor shaft. Now
pull the main rotor shaft up fully, so that the dowel pin engages in the recess in the ring gear. Fix
the dome bearing holder between the mechanics side frames using M3 x 16 socket-head cap
screws, and check for axial play between the main rotor shaft and the bearings; there should be
none at all. If necessary fit additional shim washers
under the circlip to remove any lost motion.
However, take care not to place the ballraces under strain by fitting too many and/or too thick
washers.
To add or remove the shim washers always undo the dome bearing and remove the main
rotor shaft in the opposite sequence to that described for installation. On no account re-
move the circlip from the main rotor shaft!
The next step is to set the correct meshing clearance in the gearbox. Initially the meshing clea-
rance of this gearbox stage should be set too tight, so that the gears roll „hard“ against each
other. If this is not possible, i.e. if there is already detectable gear clearance at the tightest set-
ting when the mechanics are screwed together, the bottom main rotor shaft bearing 4448.12
must be removed, turned through 180°, and re-installed. If this is still not sufficient, turn the