to allow full rotation. Also cut/bend three small electrical
wipers to allow full rotation. This is not an elegant process,
so be careful. The outer circular case is thin and brittle.
You’re finished when the pot shaft rotates absolutely freely
with no binding or rough spots (Figure 4).
5) Replace the pot in the servo; press firmly, and add a
drop of super glue if necessary. Replace the gears and top
cover. Trace three pot wires to the PCB and remove
(unsolder). To those particular PCB contacts, carefully solder
two small identical resistors in an M configuration (per
Figures 5 and 6) so they can be folded down flat. Put a
small piece of electrical tape under the resistors before
folding them down to avoid short circuits.
Reassemble the servo and verify proper functioning
using a servo tester. Any binding will result in erratic
performance, so strive for perfection here. If you mess up a
servo, it’s a cheap learning experience. Save the parts to
repair other servos later.
After you’re done, clean the grease off of the servo
cases with alcohol so we can glue to it. To attach the
wheels to the servos, you’ll use one of the long mounting
screws that came with your servos instead of the short
servo horn screw. Refer back to the opening photo to see
the proper servo mounting position on the battery box.
Cruiser is a tail-dragger and CG is important (Figure 7).
Use the breadboard for reference. It is mounted flush with
the bottom of the battery box; the servos are flush with the
top of the breadboard, axle forward. Test-fit your servos;
make sure everything’s square and wheels are parallel, and
use thick super glue and Zip Kicker to firmly attach servos
to the battery box. Add nice fillets around to strengthen the
bond. Wrap excess cable length around the servos and
connect the servos to the breadboard. Cruiser is almost
ready to roll!
SERVO 01.2016 39
Figure 4.
Figure 5.
Figure 6.
Figure 7.
