Insectothopter: The Bug-Carrying Bug
If you were told that a company had just invented a robotic dragonfly and it was flying around today, you might not be impressed. However, CIA developed this "Insectothopter" and flew it in the 1970s!
CIA had developed a miniature listening device that needed a delivery system, so the Agency's scientists considered building a mechanical bumblebee to carry it. However, they found that the bumblebee was erratic in flight and scrapped the idea. Then an amateur entomologist on the project suggested a dragonfly, and this prototype was built.
Crafted by a watchmaker, Insectothopter had a miniature fluidic oscillator to propel the wings up and down at the proper rate to provide both lift and thrust. A small amount of propellant produced gas to drive the oscillator, and extra thrust came from the excess gas vented out the rear.
A laser beam provided guidance and acted as the data link for the audio sensor payload. This is the first flight of the insect-sized unmanned aerial vehicle called Insectothopter. Flight tests were impressive. Performance measures indicated a range of 200 meters and flight time of 60 seconds with a 1-gram launch weight.
But because control in even a slight crosswind proved too difficult to overcome, Insectothopter never became operational.