EP-4741287-A2 - SYSTEMS AND METHODS FOR MANAGING ICE ACCRETIONS DURING FLIGHT OF AIRCRAFT

EP4741287A2EP 4741287 A2EP4741287 A2EP 4741287A2EP-4741287-A2

Abstract

Embodiments of the present disclosure provide systems and methods for averting, shedding, or otherwise managing ice accretions that may develop during flight of an aircraft. Example systems and methods selectively modulate propeller parameters in a way that does not disrupt a flight trajectory; direct oil from a lubrication and cooling path to targeted sections of ice-prone surfaces to manage ice accretion in a way that does not unduly increase the total volume of oil, require larger pumps, or complicate the system; or generate heat at targeted areas of a propeller assembly by electric heating systems that utilize propeller motion.

Inventors

Leopold, David
SPITERI, Stephen Michael
MARIUS, DIEDERIK
DROANDI, GIOVANNI
TULSYAN, BHARAT
GRAVES, Scott Michael
DESAI, Sujay

Assignees

Archer Aviation Inc.

Dates

Publication Date: 20260513
Application Date: 20240830

Claims (18)

A method of managing ice accretions on an aircraft, the method comprising: determining an icing condition of the aircraft; and performing a propeller modulation based on the icing condition, wherein performing the propeller modulation comprises: modulating a first propeller parameter of a first set of one or more propellers of the aircraft in coordination with a modulation of a second propeller parameter of a second set of one or more propellers of the aircraft, wherein the first propeller parameter and the second propeller parameters are different parameters, each comprising one of: revolutions per minute (RPM), blade pitch angle, electric engine torque, propeller tilt angle, or propeller angular position about a propeller blade rotation axis, of the corresponding first or second set of one or more propellers.
The method of claim 1, wherein one of the first propeller parameter or the second propeller parameter comprises RPM; and, optionally wherein performing the propeller modulation comprises: increasing the RPM of the corresponding first or second set of one or more propellers by at least 50 percent; or increasing the RPM of the corresponding first or second set of one or more propellers to at least 80 percent of a maximum RPM.
The method of claim 1, wherein one of the first propeller parameter or the second propeller parameter comprises blade pitch angle; and, optionally wherein performing the propeller modulation comprises changing the blade pitch angle of the first set of one or more propellers by at least 5 degrees.
The method of claim 1, wherein one of the first propeller parameter or the second propeller parameter comprises electric engine torque; and, optionally wherein performing the propeller modulation comprises repeatedly braking and accelerating the first set of one or more propellers to induce vibrations in propeller blades of the first set of one or more propellers.
The method of claim 1, wherein one of the first propeller parameter or the second propeller parameter comprises propeller tilt angle
The method of claim 1, wherein performing the propeller modulation comprises changing the propeller tilt angle of the corresponding first or second set of one or more propellers by at least 10 degrees during a first time interval.
The method of claim 1, wherein one of the first propeller parameter or the second propeller parameter comprises propeller angular position about the propeller blade rotation axis.
The method of claim 7, wherein: the one of the first propeller parameter or the second propeller parameter comprises propeller angular position about the propeller blade rotation axis, wherein modulating the propeller angular position comprises moving at least one propeller of the corresponding first or second set of one or more propellers from a first angular position to a second angular position, the at least one propeller comprising at least a first blade and a second blade; wherein in the first angular position, a first surface of one of the first blade or the second blade is facing away from a forward airflow, and a second surface one of the first blade or the second blade is facing toward the forward airflow, and in the second angular position, the second surface is facing away from the forward airflow, and the first surface is facing toward the forward airflow.
The method of claim 8, wherein any one of: the first surface comprises a tip of the first blade, and the second surface comprises a tip of the second blade; the first surface comprises a leading edge of the first blade, and the second surface comprises a trailing edge of the first blade; the first surface comprises a leading edge of the first blade, and the second surface comprises a leading edge of the second blade; or the first surface comprises a trailing edge of the first blade, and the second surface comprises a trailing edge of the second blade.
The method of claim 7 or 8, wherein the at least one propeller comprises a tilt propeller, and the other of the first propeller parameter or the second propeller parameter comprises propeller tilt angle.
The method of claim 7 or 8, wherein the at least one propeller comprises one of a lift propeller or a tilt propeller, and the other of the first propeller parameter or the second propeller parameter comprises electric engine torque.
The method of any preceding claim, wherein: modulating the second propeller parameter is configured to compensate an effect on flight characteristics of modulating the first propeller parameter; or modulating the second propeller parameter is configured to perform ice management together with modulating the first propeller parameter.
The method of any preceding claim, wherein performing the propeller modulation further comprises: modulating a third propeller parameter in the second set of one or more propellers of the aircraft, the second set being different from the first set, to compensate an effect on flight characteristics of modulating the first propeller parameter; wherein the third propeller parameter comprises one of RPM, blade pitch angle, electric engine torque, propeller tilt angle, or propeller angular position about a propeller blade rotation axis, of the second set of one or more propellers.
The method of claim 13, wherein the third propeller parameter is the same as the first propeller parameter; or the third propeller parameter is different from the first propeller parameter.
The method of claim 1, wherein determining the icing condition is based on: a primary ice detector; or an input from a flight control system or an input from a pilot, the input indicating an icing condition exists.
The method of any preceding claim, further comprising: determining an aircraft state, and performing the propeller modulation when the aircraft state meets one or more predefined parameters; and, optionally wherein the one or more predefined parameters comprises one of control margin status, current bank angle, load factor, vertical airspeed vs. commanded airspeed, altitude, propulsion system integrity, signal integrity, or flight mode.
A computer readable medium that stores a set of instructions that is executable by at least one processor of an apparatus to cause the apparatus to perform the method of any one of claims 1-16.
A flight control system for an aircraft, the flight control system comprising: a memory storing instructions; and a processor configured to execute the instructions to cause the flight control system to perform the method of any one of claims 1-16.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority of U.S. Provisional Application No. 63/587,117, titled "Systems and Methods for Managing eVTOL Flight in Icing," filed September 30, 2023. TECHNICAL FIELD This disclosure relates generally to the field of powered aerial vehicles. More particularly, and without limitation, the present disclosure relates to innovations in tilt-rotor aircraft that use electrical propulsion systems. Certain aspects of the present disclosure generally relate to systems and methods for preventing or mitigating ice accretion in electric aircraft. Other aspects of the present disclosure generally relate to improvements in ice prevention or mitigation that may be used in other types of vehicles but provide particular advantages in aerial vehicles. BACKGROUND An electric vertical takeoff and landing (eVTOL) aircraft typically includes one or more electric propulsion units ("EPUs"), each including at least one (full or partial) electric or hybrid-electric motor and at least one propeller. The propeller includes a plurality of propeller blades (sometimes molded or integrated as a single piece) that rotate about a propeller hub when driven mechanically by a propeller shaft. Each EPU generates thrust by its motor(s) converting electrical power into mechanical shaft power to rotate the propeller blades. SUMMARY Embodiments of the present disclosure provide systems and methods for preventing or mitigating (collectively "managing") ice accretions during flight of any aircraft. Some embodiments of the present disclosure provide a method of managing ice accretions on an aircraft, the method comprising: determining an icing condition of the aircraft; performing a propeller modulation based on the icing condition, wherein performing the propeller modulation comprises: inducing a first ice management cycle in a first set of one or more propellers of the aircraft, inducing a second ice management cycle in a second set of one or more propellers of the aircraft, the first set of one or more propellers being different from the second set of one or more propellers, and the first ice management cycle occurring at a first time interval that is different from a second time interval of the second ice management cycle. Some embodiments of the present disclosure provide a propeller assembly for an aircraft, comprising: a propeller; a motor assembly coupled to the propeller; a heat exchanger; an oil flow path configured to thermally couple the heat exchanger to the motor assembly, the oil flow path comprising a first segment, a second segment, and a third segment; and a nacelle mechanically coupled to the motor assembly, the nacelle comprising an air inlet configured to direct air into the heat exchanger, the air inlet comprising a lower lip with respect to a forward flight configuration and an upper lip opposite the lower lip, the lower lip being farther from the motor assembly than the upper lip, wherein: the first segment passes through motor assembly; the second segment passes through the heat exchanger; the third segment passes along the lower lip, and the oil flow path bypasses the upper lip. Some embodiments of the present disclosure provide a propeller assembly for an aircraft, comprising: a propeller comprising: a hub; and a plurality of propeller blades, each of the plurality of propeller blades comprising a blade channel inside the propeller blade and configured to circulate fluid; a motor assembly configured to rotate the propeller about a rotation axis; and an oil flow path configured to circulate oil through the motor assembly and through each blade channel of the plurality of propeller blades to thermally couple the motor assembly to the plurality of propeller blades; wherein the propeller assembly is configured to transfer heat from the motor assembly to an external environment outside the propeller assembly by thermal conduction through the propeller blades. Some embodiments of the present disclosure provide a propeller assembly for an aircraft, comprising: a propeller comprising: a hub; and a plurality of propeller blades, each of the plurality of propeller blades comprising a blade channel inside the propeller blade and configured to circulate fluid; a motor assembly configured to rotate the propeller about a rotation axis; and an oil flow path configured to circulate oil through the motor assembly and through each blade channel of the plurality of propeller blades to thermally couple the motor assembly to the plurality of propeller blades; wherein the plurality of propeller blades comprises a sole heat exchanger of the motor assembly. Some embodiments of the present disclosure provide a propeller assembly for an aircraft, comprising: a propeller hub; a propeller blade coupled to the propeller hub; a spinner coupled to the propeller hub; a spinner rod coupled to the propeller hub; an electrically conductive portion; a motor configured to rotate the pro