GRAUPNER Heim Eurocopter Bo 105 CBS Mode D'emploi page 58

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Bo 105 CBS
Open the angle gearbox again, remove the bevel gear from the long shaft, and grind a flat in the
shaft where one of the bevel gear grubscrews will engage. Re-fit the bevel gear exactly in the
previously established position on the shaft, and tighten the two grubscrews with thread-lock
fluid to produce a permanent joint.
Pack the angle gearbox housing about half-full with grease, then join the housing shells and
screw them together carefully.
1.6.2.3 Installing the drive shaft support rail
Cut the channeled rail to a length of 510 mm (keep the waste piece!). Place the shaft sleeve in
the channeled rail and slide the fuel tubing rings up against the ends of the rail so that they
clamp it in position.
Wind a strip of adhesive tape round the ends of the channeled rail so that the sleeve cannot fall
out.
1.6.2.4 Final installation of the tail rotor drive system
In the two preceding sections you have already assembled and trial-fitted the tail rotor drive
system, so you can now be confident that the parts fit, and that you know their correct location.
Apply UHU plus endfest 300 along the full length of the channel in the channeled rail. Rotate the
teflon sleeve in the channel in order to distribute the epoxy thoroughly.
Fit this assembly in the fuselage again from the tail end, as described in 1.6.2.2, and engage the
shaft in the quick-release coupling at the front end. Countersink the holes for the angle gearbox
retaining screws, then fix the angle gearbox in place using M2 countersunk screws. The tail
rotor is secured using three 2.9 x 13 mm self-tapping screws, and the shaft is secured with the
two grubscrews. Check the length of the long drive shaft once more, i.e. the clearance in the
quick release coupling yoke.
Rotate the channeled rail so that the channel is on the underside, and position it so that its rear
end is located about 80 mm short of the front edge of the angle gearbox.
Before the epoxy cures, rotate the tail rotor several times so that the tail rotor shaft and the
guide sleeve settle into their most natural position; now allow the epoxy to cure for about 10
hours. During this period a little epoxy will run out of the rail and onto the bottom of the tail
boom, fixing it to the fuselage shell; when the glue has set hard you should apply a little more
epoxy to this area to reinforce the joint.
Fix the collet 56.0 to the shaft at a point about 1 - 2 mm behind the quick-release coupling
sleeve.
1.6.3 Tail rotor control linkage
The tail rotor control linkage is based on a cantilever carbon fibre pushrod, a ballraced 60º
bellcrank and a second pushrod. The output arm of the tail rotor servo must point up, and not as
described in the mechanics instructions; the servo should be installed with the cable exit at the
bottom.
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