Page 41 - Festo Smartbird

The measure of efficiency of Festo’s SmartBird is its opti-mised overall efficiency factor. As with all flying devices, this comprises an electromechanical and an aerodynamic component.

In 1882, the French physiologist Étienne-Jules Marey was the first to identify twelve phases of bird flight within the space of a second. Reconstruction of this sequence of motion was to provide accurate information for the con-struction of flying machines. Using Marey’s historical ex-perimental setup as a bionic foundation, the scientists from Festo reconstructed this circular flight path configu-ration in modified form for measurements of SmartBird’s performance.

The artificial bird is attached to a rotating boom. If the boom is powered by a motor, the lift and drag of the flight model can be determined. When the bird flies around the circular track under the power of its own wings, the engineers can determine the thrust. With this intricate experimental setup, the thrust and lift can be studied over a broad range of speeds. Measurement of the mechanical power rating of the articulated torsional drive unit is car-ried out during flight on an absorption dynamometer. The ratio of this quantity to the electrical power rating yields the electromechanical efficiency factor. The aerodynamic component is determined by calculation. SmartBird can attain an exceptionally high aerodynamic efficiency factor of 70 to 80 percent.