A Study on Propeller Efficiency and Dynamics in Open air, Duct, and Hovercraft Environments

PAC Gym

Propeller dynamics are complex due to the varying factors that contribute to the seemingly one action. Though the theory behind lift from a propeller is simply the conservation of momentum, when looking into the efficiency many factors come into play. Turbulence around the blade and vibrations caused by the motor itself yield a sinusoidal production of lift from the source. To study the efficiency the power was altered, yet known, when running each trial and the lift force was measured yielding a power vs. lift relationship. However this does not directly yield the power output of the motor. Do test this, a high-speed camera was used while dry ice was held to bubble over the propeller making the air visible. Then using a tracking program, the speed of the air could be determined and an estimate of the power in the air could be made. In addition to the efficiency tests, we looked into how having a duct propeller would alter the efficiency.Hovercraft’s take advantage of a slight pressure increase due to the inflowing air in a duct environment that is held on the ground. From this knowledge we were able to build a low power hovercraft that could life many times what the propeller could in open air. From this research many future opportunities arose; how different propellers may be fit for different motors and how resonance from the lift could be matched with a hovercraft to increase efficiency.