There has been an increasing interest in the development of MAV's (Micro-Air Vehicles). The term MAV refers to a new type of remotely controlled aircraft (UAV) that is significantly smaller than similar aircraft's, obtainable by using state of the art technology. The target dimension for MAVs today is approximately 15 centimeters (six inches) and development of insect-sized aircrafts is reportedly expected in the near future.
Potential military use is one of the driving factors, although MAVs are also being used commercially and in scientific, police, and mapping applications. There are many different types of MAV's that have been developed over the years. The ornithopter is one among them.
An ornithopter is a machine designed to achieve flight by flapping wings like a real bird. The idea was to create an ornithopter from scratch, to control it remotely, and of course to make it fly!
The wingspan is the first parameter to choose, and in this ornithopter shall be 1.2 m. The approximate weight and frequency of flapping can also be figured out, which will automatically decide the rating of motor and gear ratio to be used.
As for the flapping mechanism, the transverse shaft mechanism is used. In this mechanism, the rotating gears and the flapping wings are not on the same plane, so the connector has to be able to rotate. This mechanism makes the ornithopter heavy but it also allows for the most symmetrical flap. Control of the ornithopter is achieved by a flight controller and receiver.
The power module consists of li-po batteries, esc's and servos. Carbon fiber is used in making the fuselage of the ornithopter, and as for the wings, nylon fabric is used.
Initailly the team decided to make models of the ornithopter on CAD and test out the optimal characteristics we needed from the ornithopter. After some testing and understanding, we decided to keep an optimal amount of gear reduction that gives the best flight for the wing size. We decided on using spur gears for the low frictional loss they provide. Further implements were also made on the design for allowing the wings to move and allow flight.
Coming to the testing side, since ornithopter have no vertical fin stability, making sure the ornithopter in a stable manner will be challenging. The team has decided on using different sizes of rear fins and flapping implements to allow for smoother manuevering without the loss of control.