Improving Propeller Efficiency with Software
Pipistrel, a Slovenian company, now a subsidiary of Textron, has invented an algorithm to get the most out of propellers of electric flying vehicles. As the patent states, “The algorithm incorporates information such as the propeller diameter (D), the maximum power, torque, and RPM of the propeller. Thrust, power and torque are used as functions of advance ratio (J) and blade angle can be calculated based on altitude, RPM demand, and true air speed.”
The software takes into account all data relating to the system’s behavior and adjusts parameters for optimal and energy-efficient operation. The software’s data sources are: true airspeed, propeller characteristics (diameter and blade angle), engine and propeller RPM, and the engine’s power or torque limit. If the angle of attack of the propeller’s blades can be adjusted, the system automatically chooses the most optimal angle.
It is obvious that “A propeller not operating at its peak efficiency is suboptimal and can increase costs of aircraft operation.” The software is programmed with optimal ratios for most efficient performance, and continually adjusts the RPM and blade configuration during flight. “Generally, propeller efficiency may be described as the ratio of propulsive power output to shaft power input.”
Claim 1: “A method for providing peak efficiency propeller control, the method comprising: determining an advance ratio based on a true airspeed, a diameter, and a propeller efficiency; determining an optimal blade angle of a propeller for the propeller to operate at a maximum efficiency based on a required thrust and the advance ratio; determining whether the optimal blade angle violates limits of blade angle, an engine or a propeller RPM, an engine power limit, or an engine or propeller torque limit; when the optimal blade angle violates any one of the limits, determining a non-optimal blade angle to achieve a maximum available thrust such that the non-optimal blade angle does not violate any one of the limits, and transmitting the non-optimal blade angle to an actuator configured to physically adjust the blade angle of a propeller; and when the optimal blade angle does not violate any one of the limits, transmitting the optimal blade angle to the actuator configured to physically adjust the blade angle of the propeller.”
Title: “Peak Efficiency Propeller Control”
US Patent Application No: 20240375767
Filed (US Prov.): 2023-05-09
Published: 2024-11-14
Applicant: Pipistrel d.o.o.
