Starlet 50
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sufficient to eliminate the gear clearance, you will also have to turn the bottom layshaft bearing
bracket through 180° horizontally. Turning these parts round in this way compensates for any
slight offset of the brass inserts in the bearing supports; such offsets are an inevitable feature of
the production process and can never be completely eliminated. The meshing clearance
between the spur gear and the layshaft pinion can now be adjusted by slightly loosening the M3
x 16 socket-head cap screws in the bearing brackets, fitting a strip of stout writing paper
between the gears, and then tightening the screws again, holding the gears hard against each
other. Wind the strip of paper out, and the gearbox should now run smoothly, with no tendency
to jam or stiffen at any point; if you are not satisfied, repeat the adjustment process with a little
greater care.
1.5 Installing the motor
(bag UM-2)
The mechanical assembly of this helicopter is designed for a motor with a long ground 8 mm Ø
crankshaft, as specified for all Graupner / Heim model helicopters. However, other types of
motor can also be installed at the modeller’s discretion; all you need is the optional plain bearing
clutch, which is available separately.
Remove the washers and nut from the crankshaft, then fit the following parts on the shaft in this
order: stepped washer 4450.38, two ballraces 4618.78, split taper collet 4618.77, clutch bell
4618.23, clutch 4618.79, cooling fan 4450.2, followed by the washer supplied with the motor. Fit
the crankshaft nut and tighten it securely.
If you find that tightening the crankshaft nut pushes the taper collet completely inside the clutch,
without the collet exerting adequate clamping pressure on the crankshaft, then you must fit an
8/13 x 0.5 mm washer (from 4450.58) under the taper collet, otherwise the clutch may slip on
the crankshaft when the motor is running. Fix a linkage ball to the outermost hole in the
carburettor arm using an M2 x 10 screw and nut.
