| Description |
Quadrotors have come to serve myriad purposes and have seen use as platforms for diverse activities including videography and remote sensing. These versatile aircraft, however, cannot remain in flight for extended periods of time. This is due to several factors including the aerodynamic regime in which they operate and the specific energy limitations of modern battery technology. Flight time can be extended by reducing the weight of the craft through advanced composite construction, and by optimizing the choice of motor, propeller, and overall vehicle weight. Additionally, as this paper investigates, aerodynamic devices such as shrouded rotors can be used. These devices consist of an annular duct that surrounds a propeller. They promote the expansion of the wake, thereby reducing the induced power requirements to accelerate the flow. These devices have been studied since the 1930s and are commonly seen on helicopters as well as ships. Using this previous work two different shroud geometries were selected and printed using PLA. The open rotor and shrouded rotors were subjected to static thrust tests, with the data being analyzed in MATLAB. Overall the shrouds demonstrated maximum thrust increases of 17.2% and 9.0% for the different configurations. Using the results of this effort, flight time projections were made for shrouds of varying weight, and compared against flight time data of an open rotor quadcopter. Despite a demonstrable increase in thrust, the weight of the shroud was found to expend most if not all of the improvements in thrust generation. |
