Dragonfly Science by thinkpool

Last crawled date: 3 years ago

We have completed the prototype of a mechanical radio control dragonfly and we are collecting funds to bring it to market. The KickStarter will allow you to purchase the Dragonfly RC or you can invest in our company GadgetANNI. Details on how you can own a part of GadgetANNI will be posted shortly. If you have questions please message me through your Thingiverse account.
Thank you
One of the most fascinating creatures on Earth, the dragonfly has a very ancient stroke. It's an up-and-down stroke instead of a back-and-forth stroke. An airfoil uses aerodynamic lift to carry its weight. But the dragonfly uses a lot of aerodynamic drag to carry its weight. What’s odd is that with airplanes you always think about minimizing drag, you never think about using drag for lift.
The physics of dragonfly flight inspired me to build a mechanical dragonfly based on scientific research by Z. Jane Wang, professor of theoretical and applied mechanics at Cornell University, and Akira Azuma research papers. This design utilizes drag to create flight by using theoretical models including momentum theory and the blade element theory.
The inspiration for this mechanical insect originated from many of the fantasized gadgets of Leonardo da Vinci and other mechanical creations once thought futuristic in times long before our own.
The wings
The design of the wings were crucial to figure out how to use drag to create flight.
Dragonflies are insects belonging to the order Odonata, which wings move independently during flight. As the forewing lifts, the hindwing lowers.
They have two pairs of similarly sized long thin membranous wings.
Its fore and hind wings are controlled by separate muscles, and a distinctive feature of the dragonfly’s wing movement is the phase relation between those wings during various maneuvers. Creating oscillating wings at a specific distance apart develops whirls on top of opposing wings which creates lift.
Wings had to be close enough for them to interact hydrodynamically.
The engine
The engine that flaps the wings is driven by a twisted rubber band that turns a crank shaft. Mimicking natures design while maintaining a simple design was testing so we defaulted to a proven design. The reason for this decision was influenced by the nature of how a dragonfly uses its muscle.
A dragonfly's muscles flap its wings by flowing blood in its veins which manifest Coriolis forces.
When muscles attached to the dorsal surface of the thorax contract, they pull down on the tergum. As the tergum moves, it draws the wing bases down, and the wings, in turn, lift up. Another set of muscles, which runs horizontally from the front to the back of the thorax, then contract. The thorax again changes shape, the tergum rises, and the wings are drawn down.
Dragonflies perform at low speed flight with ordinary airfoil characteristics, instead of adopting an abnormally large lift coefficient.
Wing movement
The flapping rate of the wings maintain the forces that keep the dragonfly air born. We compromised the wing speed from 30 beats per second to 2 beats per second and added a gliding feature to the design. Dragonflies are also good gliders. Some larger species can glide for 20 m at angle of 10 degrees.
Dragonflies flap and pitch their wings at a rate of about 40 Hz. The blood flowing in veins induces Coriolis forces in the flapping wings.
The body design
When art and science do merge, the result often becomes an elaboration on scientific data through a more artistic medium. The most sturdy and elegant design for the body was to use a "X" shape along the tail and underbelly. The sturdiness of the design allows for greater pressure from the twisting of the rubber band.
https://youtu.be/r8CszYNxGHg