Assembling The Tail Rotor Gearbox - GRAUPNER heim UNI-Mechanik 2000 Mode D'emploi

UNI-Mechanics 2000

4. Assembling the tail rotor gearbox

(bag U2-11, UM-11A)
Fit the bevel gear 4618.38 on the tail rotor shaft 1221 as shown in the illustration. Apply thread-
lock fluid to the threaded holes in the bevel gear, then tighten the M3 x 3 grubscrews fully; note
that one of the two grubscrews must engage squarely on the flat section of the tail rotor shaft.
Do not tighten the grubscrews to the point where the bevel gear is under strain, as it will then
run out of true. Fit the spacer sleeve 4450.28A and the bearings 4618.69 and 4450.22 on the
shaft, pushing the parts hard up against each other. Slide this assembly into the tail rotor hou-
sing 4618.73 as far as it will go, and secure it with the M2 x 4 retaining screw. Check that there
is absolutely zero axial play, and fit 5/10 x 0.1 shim washers if necessary.
Fit the ballraces 4618.69 and the spacer 4618.66 on the tail rotor input shaft 4448.40 as shown
in the illustration. Apply bearing retainer fluid, Order No. 951, before fitting the bearings.
The bearings must not be under stress; if necessary tap on them using a screwdriver handle or
similar, so that they automatically seat correctly on the shaft. Allow the bearing retainer fluid to
dry.
Fit a 5/10x0.1shim washer and a bevel gear 4618.38 on the tail rotor input shaft 4448.40 as
shown in the illustration without using bearing retainer fluid at this stage.
Fit and tighten the M3 x 3 grubscrews in the bevel gear. Note that one of the two grubscrews
must engage squarely on the machined flat in the tail rotor input shaft.
Now fit the prepared drive shaft assembly into the tail rotor housing, and line up the hole in the
spacer 4618.66 with the hole in the tail rotor housing, then secure it with an M2 x 5 countersunk
screw.
Fit a steel rod (screwdriver blade or similar) through the threaded holes in the coupling 4448.40.
Using the rod as a handle, pull hard on the coupling (against the countersunk screw joint), so
that the tail rotor drive assembly seats itself in the housing with maximum possible gear
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