A Study of the Effect of Yoke Size on Propeller Performance

The following study explores the effect of yoke size on propeller performance. The yoke is the part which attaches the propeller to the rotor, this acts as a sort of a moment arm, which when extended the local speed of the blade will be higher due to the increase in radius. The method used to test the performance of the yoke will be based on blade element momentum theory. This is done by comparing the performance of the geometric model created to actual wind tunnel data. Although there won’t be a perfect match, their results should be close and have a small difference for more accurate results. The propeller used and tested is the Aeronaut 20x8. The 20x8 is being tested for the means of improving the overall power train efficiency of CREATeV, a lightweight solar powered aircraft built for endurance. The flight speeds considered for the analysis are between 8-12, with an rpm range of 2000 to 5500. The results find that increasing the yoke size increases the propeller efficiency by up to 4%. With a decreased power requirement during cruise for CREATeV. The yoke size for maximum propeller efficiency does not change much with speed, indicating that the yoke size mainly depends on the geometry of the propeller more than it does flight conditions.