Engineering 101

The Insectothopter and the birth of the Micro Aerial Vehicle (MAV)

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It was the 1970s, the Cold War was in full swing, and the U.S. Central Intelligence Agency’s Office of Research and Development had developed a miniaturized listening device. But they didn’t have a good way to maneuver the device into place without raising suspicions.

After scrapping the idea of a mechanical bumblebee, CIA engineers prototyped a dragonfly to carry the bug. Dubbed the Insectothopter, the bug-carrying bug was the agency’s first insect-size Unmanned Aerial Vehicle (UAV), and it seemed to show potential. Under ideal conditions, it had a range of 200m and a flight time of 60 seconds.

Flight Kit: The propulsion system for the Insectothopter was based around a miniature fluidic oscillator, which moved the wings up and down to mimic a real dragonfly’s flight.

In taking a cue from nature, CIA engineers were wise to choose the dragonfly. Dragonflies are nimble aerialists, able to hover, glide, and even fly backward. They can turn 180° in three wingbeats. The Insectothopter’s 6cm-long body and 9cm wingspan were well within the range of an actual dragonfly’s dimensions. Plus, dragonflies are native to every continent except Antarctica, so their presence would be unremarkable, at least in the appropriate season.

cia-museum
Credit: CIA Museum

According to a CIA description, the robobug was supposed to work like this:

A laser beam directed at a bimetallic strip in the insectothopter’s tail guided the device. That same laser beam acted as a data link for the miniature acoustic sensor onboard the craft. A miniature oscillating engine drove the wings; the fuel bladder contained a liquid propellant that when mixed with an oxifier created additional thrust.

Unfortunately, even the gentlest breeze blew the one gram Insectothopter off course. It’s unclear if the laser guidance and data link were ever implemented. In any event, the UAV never flew an actual spy mission.

Decades later, though, dragonflies remain popular research models for UAVs. Beginning in 2005, students at Delft University of Technology in the Netherlands created the DelFly to compete in an international Micro Aerial Vehicle (MAV) competition. The original design, with a wingspan of 50cm and a weight of 21g, wasn’t exactly dragonfly size. Several iterations later, the DelFly Micro debuted with a more realistic 10cm wingspan and a weight of only 3.07g. This robotic dragonfly carried a video camera and transmitter to send live video. In 2008, it set a Guinness World Record as the “smallest camera plane.”

Meanwhile, toy companies began marketing radio-controlled robotic dragonflies. Time magazine named WowWee’s FlyTech Dragonfly one of the best inventions of 2007, although reviews suggested that crosswinds also posed a challenge for this tiny flyer. With 20cm translucent wings imprinted with a faux circuit design, pudgy white-and-green body, and glowing blue LED eyes, the FlyTech wasn’t exactly fit for spycraft, but it proved popular with both kids and adults.

More recently, engineers have taken a different approach to building a better robotic dragonfly. Researchers at Draper, in Cambridge, Mass., and the Howard Hughes Medical Institute at Janelia Farm are genetically modifying real dragonflies so that their nervous systems respond to pulses of light, and then equipping the insects with a backpack of electronics. The cybernetic MAV is called DragonflEye. While technologically intriguing, it does raise ethical concerns about tinkering with nature and about the nature of surveillance.

The Insectothopter is currently on display at the CIA Museum. However, because the museum is housed within the secure CIA headquarters in Langley, Va., it is not open to the general public. Instead, the agency has made photos of the device available online, along with this historic footage of the MAV in flight:

Source IEEE Spectrum

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