GRAUPNER heim Bell 230 Instructions D'utilisation page 49

Bell 230
1.5.4 Main retract unit actuating linkage
The first step is to check that there is at least 4 mm free space all round the aluminium tubes
F31 which project through the holes in the formers A7; if not, open up the holes in the formers;
they don't need to be exactly circular.
Mount two linkage balls in the innermost holes of the two remaining levers F24 using M2 x 8
screws. Fit a collet F26 on the shaft of the each lever, resting flat against the lever itself. Glue
the bushes F25 in the wooden discs A8; when the glue has set, fit the bushes onto the shafts of
part F24, with the flanged side facing the lever. Slip these assemblies onto the aluminium tubes
F31 and set the discs A8 resting against the formers A7; they should not be under strain. It
should still be possible to extend and retract the undercarriage legs at this point. Once you are
sure of this, glue the discs A8 to the formers A7 in the correct position; take care to keep them
exactly flat on the formers. Allow the epoxy to set hard, then pull back the levers F24 on the
aluminium tubes F31 to leave a slight space between the bush F25 and the collet F26. Now
rotate the levers F24 on the shafts F31, and check that the undercarriage legs can be retracted
reliably and locked fully without the levers F24 striking the bulkhead A20; there should be about
3 mm clearance at the end-point. The grubscrews in the collets can now be tightened fully with
the parts in this position.
Make up the connecting pushrods between the servos and the undercarriage levers from the
M2 x 60 threaded rods and the ball-links 4618.55; the distance between the ball centres should
be about 40 mm.
Connect the servos to the receiver using the Y-lead arrangement already described, so that you
can adjust the entire retract system; if you are using a Graupner radio control system, set the
servo travel for the retract channel to 100% on both sides of neutral. The retract system should
be operated by a toggle switch on the transmitter. Adjust the pushrods and servo output arm
positions with the wheels extended until you are confident that the mechanical lock on the wheel
legs operates with complete reliability, without stalling any of the servos. Now retract the legs
and check that they also lock mechanically in the retracted position, without the servos showing
signs of overloading or stalling. You may find that you have to adjust the pushrods and servo
outputs carefully before you achieve a satisfactory result.
Don't attempt to set the correct travel by adjusting the servo travel on the transmitter, as this
would wreck the adjustment of the noseleg unit which you have already set.
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