Wing Mill Energy Harvesting
The purpose of this research is to demonstrate the feasibility of wind energy generation from flapping wings. Current Horizontal Axis Wind Turbines require large towers to lift them into high quality laminar flow fields. Limited research has suggested that a wing–mill may have comparable efficiencies to a traditional HAWT. In addition it has been speculated that this device may favorable efficiencies in turbulent environments that challenge HAWTs.
Several wing–mill form factors were examined and a four–wing configuration connected to a central crankshaft via four–bar mechanisms was selected. The four–bar mechanisms transform the reciprocating motion of the wings to the rotary motion of the crankshaft. Wing pitch is controlled via bumpers at the top and bottom of wing travel. When a wing hits a bumper, the angle of attack is reversed and the pitching moment on the wing acts to hold the wing against the a pitch limiting stop as the wing travels through the next half of its cycle. A wind tunnel prototype was developed and is shown in Figure 1. This model was used to gather efficiency data and validate a computer simulation of the wing mill dynamics.
A full–scale prototype is completed and has four 7–foot wings. Current work is focused on improving the existing design and measuring efficiencies in outdoor trials.