Temporarily Mount the HoverFly
Open Board ( 10 minutes)
Photo 14. Close-up of 12 gauge wire
power harness solder joint.
Photo 15. Power harness in place.
The HoverFly Open Board is not much
larger than an ESC (see Photo 16). At this
point, the instructions suggest mounting
the board using silicone grommets and
self-tapping screws as in Photo 17.
However, I managed to strip two of the
bolts during wiring and testing. In place of
the original metal screws, I installed nylon 4-
40 hardware which works fine. I suggest
you use tie-wraps to secure the board until
you're ready to fly.
Prop Balancing and Test
Mounting (1-2 hours)
The final step in the physical build is to
balance the propellers, install a shaft
adapter, and test the mount. It's the
balancing act that takes time, and that's
going to make the difference between a
flying machine and a self-destructing egg
To balance each prop, you can use a
jig and razor or sandpaper or
whatever method works for you —
just make certain each propeller is
balanced or the craft will vibrate
wildly. I use a Turnigy R/C Balancer
($13, HobbyKing) and a set of
coarse to fine Emory boards.
Next, insert a 5 mm plastic
shaft adapter into each of the
props. Each prop ships with a set
of six adapters — pick the adapters
that best fit the aluminum collets;
5 mm worked for me.
Recall that two propellers
turn clockwise and two turn
counterclockwise. You should be
able to tell from Photo 18 that the
pitch is such that downward thrust results from
Mount the balanced props with collet
adapters onto the motors. Slide the prop onto the
adapter, screw on the bullet shaped cone, and
tighten using a small hex wrench inserted
through the holes in the cone. The cones need to
be good and tight.
If there is slippage, now is the time to repair
or replace the collets. Remove the props and
collets in preparation for electronic setup and
HoverFly Open Board size
comparison with motor, ESC, and
4,400 mAh LiPo battery.
Photo 17. HoverFly Open Board
50 SERVO 09.2012