DEVELOPMENT OF ROBUST TWO-CYCLE ENGINES FOR PERFORMANCE FLEXIBILITY USING MODULAR DESIGN

摘要

As the utility of unmanned aerial vehicles (UAV) becomes more defined and potential applications increase, the performance requirements for the power plant are being greatly increased. Larger payloads, short take-off, long service life, fuel economy, and acoustic levels all directly impact power plant design. A survey of existing UAV power plant/aircraft configurations is presented in a comparative format to provide background and historical perspective. A review of recent literature is discussed to show the relevant trends in the development of modern two-cycle, spark ignition engines. In this paper the development and testing of a robust power plant specifically designed for current UAV applications is described. Among many factors, a robust power plant must; produce a favorable horsepower-to-weight ratio (greater than 1:1); be reliable with a long service life (a time before overhaul greater than 500 hours); and the ability to meet performance criteria over a broad range of operating conditions. The entire design/development/testing process is detailed. Beginning with a design statement which defines the objectives and implications of a modular design methodology, the process passes through the utilization of CAD/CAM for the rapid development of near production level prototypes, and completes with engineering test and evaluation. By employing modular design concepts the basic power plant configuration is shown to be robust and flexible for a wide range of potential applications. Engineering test data including; speed-torque, power recovery, fuel efficiency, and acoustic signature are presented and compared with design objectives.