This paper focuses on strong propeller effects in a full six degree-of-freedom (6DOF) aerodynamic modeling of small UAVs at high angles of attack and high sideslip in maneuvers performed using large control surfaces at large deflections for aircraft with high thrust-to-weight ratios. For such configurations, the flight dynamics can be dominated by relatively large propeller forces and strong pr...

The dominant feature in the acoustic spectrum of a propeller-driven aircraft is the spectral line corresponding to the propeller blade rate that is equal to the product of the propeller shaft rotation rate and the number of blades on the propeller. The frequency of this line, when measured by a stationary observer on the ground, changes with time due to the acoustical Doppler effect. In this pa...

A fixed-wing aircraft that is capable of low airspeed, high angle of attack flight can serve an expanded range of mission goals. A typical propeller-driven small unmanned aircraft can be equipped with an engine that provides greater thrust than airplane weight; in post-stall states, the aircraft then depends on propeller backwash over the tail for control moment generation. Due to this dependen...

The Low Speed Aeroacoustic Wind Tunnel (LSAWT) at NASA Langley Research Center has recently undergone a configuration change. This change incorporates an inlet nozzle extension meant to serve the dual purposes of achieving lower freestream velocities as well as a larger core flow region. The LSAWT, part of the NASA Langley Jet Noise Laboratory, had historically been utilized to simulate realist...

A practical online optimization scheme is developed for performance optimization of an electrical aircraft propulsion system. The goal is to minimize the power extraction of the propulsion system for any given thrust value. The online optimizer computes the optimum pitch angle of a variable pitch propeller by minimizing the power of the system for a command thrust value. This algorithm is teste...

In this paper, parametric and numerical model of the DC motor, connected to aircraft propellers are extracted. This model is required for controlling trust and velocity of the propellers, and consequently, an aircraft. As a result, both of torque and speed of the propeller can be controlled simultaneously which increases the kinematic and kinetic performance of the aircraft. Parametric model of...

A noisy environment dominated by low frequency noise can often be improved through the use of active noise control. This situation arises naturally in propeller aircraft where the propellers induce periodic low frequency noise inside the cabin. The cabin noise is typically rather high, and the passenger flight comfort could be improved considerably if this level were significantly reduced. This...

An experimental study was performed to design and analyze a "pusher" propeller for use by a small, expendable, autonomous unmanned aerial vehicle (UAV) whose mission was to descend from 30,000 feet to sea level at an approximately constant descent rate over a 3-hour mission duration. The entire propeller design process, from airfoil selection to final part generation in the computer-aided draft...