Building the Base Plate
The base plate will hold all of our speed controllers,
receiver, power distribution, and the battery. This last
item was a huge internal debate for me. Taking the top
plate off and on constantly to access the battery could
be annoying if it’s not easy. Having the battery inside
means more experiment space on the “deck” of the
drone, though. In the end, I decided to put the battery
inside, with the idea that if I must move it later it’s not a
I chose 1/8” hobby plywood (available at any craft
store) for the base plate with spacers made of pine. To
start off, I cut out a 4” x 19” piece of the plywood and
sanded off the rough edges. I pilot drilled and final
drilled the mounting holes in the base plate as shown in
Figure 4. Then, using some M3 hardware (you could use
4-40 if you want to use imperial sizes), I temporarily
bolted the motor arms to the base plate. Remember, the
open side of the channel faces inward.
After ensuring that the motor arms were at right
angles to the base plate using a speed square (Figure 5),
I tried to fit the cavity spacers in between. As planned,
they were too long and I had to rasp or sand off the little
bit needed to make the spacers fit snugly between the
motor arms. I did one final recheck that everything was
still square and tight for good measure (Figure 6).
To permanently affix the spacers to the base plate, I decided to use screws and
wood glue. I removed the cavity spacers, applied a small bead of wood glue to the
bottom of the spacer, and placed it back into location. Using some clamps, I
clamped the spacer to prevent any movement. I did this again for the spacer on the
other side of the airframe (Figure 7). Finally, I checked one more time that
everything was square.
Figure 9. My first landing leg design didn’t exactly match the pieces I cut. I also
decided that these legs were far too likely to snap on the first bad landing.
Figure 8. The top plate is
just another piece of
1/8” plywood with holes
for the alignment pegs
on the risers. I made my
holes slightly oval to
allow an easy on/off fit.
Figure 7. Clamp the risers down while the glue cures. As
soon as they are secured, remove the motor arms and wipe
away any excess glue that has squeezed out.
46 SERVO 06.2016