Amazon Technologies, Inc.

Allan Ko

Brian C Beckman

Gur Kimchi

Emilia Sorana Buneci

Vedran Coralic

Howard Lee Huddleston, Jr

Jr Huddleston Howard Lee

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the position of one or more propeller blade treatments of a propeller blade of an aerial vehicle during operation of the aerial vehicle. For example, the propeller blade may have one or more propeller blade treatments that may be adjusted between two or more positions. Based on the position of the propeller blade treatments, the airflow over the propeller is altered, thereby altering the sound generated by the propeller when rotating. By altering the propeller blade treatments on multiple propeller blades of the aerial vehicle, the different sounds generated by the different propeller blades may effectively cancel, reduce, and/or otherwise alter the total sound generated by the aerial vehicle.

Propeller blade treatments for sound control

An aerial vehicle may be equipped with propellers having reconfigurable geometries. Such propellers may have blade tips or other features that may be adjusted or reconfigured while the aerial vehicle is operating, on any basis. Propellers having reconfigurable blade tips joined to blade roots may cause the blade tips to be aligned with the blade roots, or substantially perpendicular to the blade roots, e.g., in order to counter adverse effects of tip vortices, or at any intervening angle. The propellers may be reconfigured at predetermined times during operation of an aerial vehicle, or upon sensing one or more operational characteristics or environmental conditions, as may be desired or required.

Geometrically reconfigurable propellers

Propeller blade indentations for improved aerodynamic performance and sound control

Propeller blade trailing edge fringes for improved sound control

Propeller surface area treatments for sound dampening

Aerial vehicles may be operated with discrete sets of propellers, which may be selected for a specific purpose or on a specific basis. The discrete sets of propellers may be operated separately or in tandem with one another, and at varying power levels. For example, a set of propellers may be selected to optimize the thrust, lift, maneuverability or efficiency of an aerial vehicle based on a position or other operational characteristic of the aerial vehicle, or an environmental condition encountered by the aerial vehicle. At least one of the propellers may be statically or dynamically imbalanced, such that the propeller emits a predetermined sound during operation. A balanced propeller may be specifically modified to cause the aerial vehicle to emit the predetermined sound by changing one or more parameters of the balanced propeller and causing the balanced propeller to be statically or dynamically imbalanced.

Selecting propellers for performance and noise shaping

Operating aerial vehicles with intentionally imbalanced propellers

Reconfiguring propellers during aerial vehicle operation

Propeller blade leading edge serrations for improved sound control

Described is an aerial vehicle, such as an unmanned aerial vehicle ('UAV') that includes a delivery shroud. The delivery shroud may be maintained in a retracted position while the aerial vehicle is in transit. The delivery shroud reduces the transmission of sound from the aerial vehicle to the delivery area. Likewise, the delivery shroud may also be used to facilitate delivery of a payload from the aerial vehicle to a delivery location within the delivery area.

Aerial vehicle delivery shroud

Ground effect acting on an aerial vehicle, such as an unmanned aerial vehicle, may be simulated by discharging a gas around propeller blades of the aerial vehicle while the propeller blades are rotating. For example, a gas, such as air, may be discharged at or near the tip of the propeller blades with enough velocity to disrupt the airflow around the blade tips, thereby altering the sound generated by rotation of the propeller blade.

Systems and methods for simulating ground effect

Intentionally imbalancing propellers for performance and noise-shaping

Growing community of inventors

Seattle, WA, United States of America

Allan Ko