Hack a hobby copter and see what the birds and bugs see. BY I-WEI HUANG EYE IN THE SKY d
Mounting a camera on a device that can take you where you can’t
physically go isn’t a new concept. What’s new is the size and cost
of electronics, and advances in micro radio-controlled flight.
Sam Murphy
Today you can buy a cheap, no-brand
keychain spy camera for about $20. These
are less than half the size (a pack of gum)
and weight ( 19 grams) of the FlyCamOne2,
so you can fit one in a very small aircraft to
record onboard video. Luckily, R/C aircraft
technology has also advanced in size, weight,
and performance since my last aerial video
attempt. Today there are many micro- and
sub-micro helicopters on the market, and I’ve
found a perfect-sized R/C helicopter for this
tiny camera: the Blade 120 SR from E-flite.
It’s small enough you can throw it in a backpack, yet big enough to carry the camera
without much performance loss.
Years ago I bought an Acme FlyCamOne2
video camera, able to capture 640×480 video
at 30 frames per second and yet light enough
to be carried by a standard R/C helicopter,
for around $150. I mounted it on a 400-size
helicopter with 30" rotor blades made of carbon fiber and CNC aluminum. Operating at
incredible speeds, these are more like flying
circular saws than R/C models. The sound
alone is terrifying. I was able to record some
flights around the park, and even do some
stunts like flips, loops, rolls, and inverted
hovering, while recording onboard video.
CHOOSING A MICRO COPTER
One of the biggest reasons I picked the Blade
120 SR is that it’s a fixed-pitch helicopter.
There are two types of single-rotor R/C helicopters: fixed pitch (FP) and collective pitch
(CP). Fixed pitch is exactly how it sounds:
the main rotor blades are of a fixed pitch
angle, so the amount of lift you can achieve
is based solely on how fast the motor is spinning. Much like an electric fan at your house,
the faster you make it spin, the more air is
pushed out.
In comparison, collective-pitch helicopters
have main rotor blades whose pitch is variable,
so lift is controlled by changing the pitch angle
of the blades, in addition to the RPM of the
motor. CP rotor blades can even be negative-pitched — thus the helicopter is capable of
flips, rolls, and even upside-down flight. But
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