Subsystem Acoustic Testing of a Vertical Takeoff and Landing Ducted Propeller Unmanned Aerial Vehicle

摘要

By definition a Vertical Takeoff and Landing (VTOL) Ducted Propeller Unmanned Aerial Vehicle (UAV) is an aircraft that can take off in a vertical mode, hover in place, transition into horizontal flight, transition back to vertical flight, and land in a vertical mode. This type of flight capability makes a VTOL UAV ideal for operating in areas where runways are not accessible, and in confined areas such as within an urban environment. Despite this advantage, VTOL UAVs have exhibited high acoustic levels while in VTOL flight and in forward flight that may prohibit their use in confined areas. The primary objective of this VTOL UAV test was to measure the acoustic levels of each of the components that make up a VTOL UAV, and determine which components are the primary source of the VTOL UAV acoustic signature. The secondary objective was the measurement of an electric motor with a propeller to determine if the electric motor could be used in place of a nitro-fueled engine to reduce noise. The third objective was to measure the acoustics of a similarly powered helicopter to determine if a helicopter could be used as an alternative aircraft. And the fourth objective was to measure the acoustics of several muffler alternatives. Testing included measurement of the VTOL UAV's acoustic levels at different heights above the ground. The 48 acoustic tests were conducted on a variety of test devices. The test devices consisted of a VTOL ducted Propeller UAV, an O.S. .32 2-stroke engine, a Master Airscrew 2-bladed propeller, a Jeti electric motor, a Raptor 30 size radio-controlled helicopter with a Thunder Tiger .36 engine, and 4 different mufflers. The mufflers included a Mousse Can Muffler, a MACS Products Pretuned Muffled Tuned Pipe, an O.S. Universal Muffler Assembly, and an O.S. Stock Muffler. The testing consisted of a vertical test setup to simulate hover flight and a horizontal test setup to simulate horizontal flight. (49 tables, 38 figures, 3 refs.).