FIGURE 3. New DJI Phantom UAV.
FIGURE 2. Blade 450
collective pitch helicopter.
Multi-rotor flyers do not use a tail rotor
to steer (yaw), but must rely on driving
each of the four, six, or more rotors at
different speeds to tilt and rotate.
These types of flying robots can also
require up to six or seven
R/C channels, depending on add-on
Figure 1 shows a Walkera CB
180Z that I’ve had for a while. I’ve
placed ping-pong balls on the plastic
rods to help prevent it from flipping
over after a hard landing. This copter
has eaten two sets of rotor blades and
a main gear. The brushless drive motor
used in these is quite powerful and
can chew through the main gear like a
Dremel tool when the rotor is stuck on
The Blade 450 shown in Figure 2
has a main rotor with collective pitch
and a tail rotor. It’s quite a bit trickier
to fly but is a lot of fun. Collective
pitch allows you to vary the
pitch of the main rotor’s
blades, which means you
can flip the unit over in the
air and fly it upside down.
quadcopters and multi-rotor flyers use
electrically-driven fixed-pitch props for
all the lift force, and have no
mechanical linkages to tail rotors or
complex collective pitch and swash
So, how do you fly one of these
neat quadcopters? This is where the
flight controller — or flight stabilization
controller — comes in. The result is a
very maneuverable and agile aircraft.
Multi Wii Pro shown in Figure 4 with
the attached MKT GPS module that
has the ‘go home’ capability at a
reasonable cost. The KK2 2.0 multi-rotor controller shown in Figure 5 has
an LCD panel that shows the
configuration (and other properties).
You can also see the typical
interconnections from the receiver’s
servo connectors and the outputs to
up to eight outrunner motors.
There are numerous flight
controllers that I’ve found in my
research, and prices range from less
than $30 to many hundreds of dollars.
Simpson’s articles mentioned several
good ones, including the DJI NAZA.
Another great controller is the
Makes Flying a
Take a look at the new
DJI Phantom UAV shown in
Figure 3. There is no tail
rotor to steer it. Unlike
Parallax Enters the
Market with the
ELEV- 8 Quadcopter
Parallax came out with the ELEV- 8
shown in Figure 6 last year, after fine-tuning the many mechanical aspects
and sub-systems. Control of the
vehicle’s motion is achieved by varying
the relative speed of each rotor to
change the thrust produced. It would
be almost impossible to fly
these multi-rotor aerial
vehicles without an electronic
flight controller to stabilize the
flight. Even my inexpensive
CB180Z has a three-axis gyro
system built into the receiver
to assist in level flight and
The ELEV- 8 uses a
HoverFly Sport flight controller
board shown in Figure 7,
with a Propeller multi-core
electronically control the
stabilization of the aircraft.
Figure 8 shows a
modified ELEV- 8 with a FPV
SERVO 03.2013 75
FIGURE 4. Multi Wii Pro with MTK GPS module.