View attachment 2021Probably the most critical part has been missed here, and that is the weight of the prop. Model stability is linked to the response time of the thrust demand. It has been proved beyond any doubt that the prop.s that give the best lift efficiency do not produce the best stability. Props. such as the high aspect ratio XOAR's produce a lot of noise which means that they are not suited well to static thrust efficiency. Low aspect ratio blades with fine pitch angles perform the best. For the best profile section some startling facts emerged. In a world of insect aerodynamics where reynolds numbers are useless, surface finish also yields some interesting results.