Ohad Gur

Propeller design for a mini-UAV will be presented. The design is mainly based on performance considerations. Two design conditions are considered, which make the design procedure a multi-objective design problem. In the classic propeller design method, the cost function is either the thrust at given shaft power or minimum shaft power at given required thrust. Here, the two cost functions are loiter fuel-flow at the required flight condition and the thrust at ceiling at given throttle. In this way, the cost function no longer refers to the isolated propeller, but takes into consideration the engine characteristics as part of the optimization procedure. This gives immediate performance estimation as part of the design process, and avoids the requirement to calculate the performance of the vehicle as a retroactive process after the propeller design. Three additional flight conditions are considered, which cover other required performance constraints. These include slow loiter at low altitude, catapult thrust, and climb performance. Implementation of the problem in modeFRONTIER will be presented, and the benefit of using modeFRONTIER not just as the optimization platform, but as the performance calculation tool will be discussed. Results for three different propeller concepts will be presented: an existing wood propeller family, an existing composite propeller family and an optimized (no structural consideration) propeller family.