# US 11,440,649 B2 · Assisted landing systems for rotorcraft > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,649 B2 - Document ID: US11440649B2 - Status: Granted - Kind: B2 - Application number: 17/134,378 - Filed: 2020-12-26 - Published: 2021-04-22 - Granted: 2022-09-13 - Earliest claimed: 2018-05-17 - Assignees: Textron Innovations Inc. - Applicants: Textron Innovations Inc. - Inventors: Frank Bradley Stamps; Michael K. McNair; John Richard McCullough - Web page: https://patentgrep.com/patent/US11440649B2 ## CPC - B64C 27/006: {Safety devices} - B64D 27/10: of gas-turbine type (jet aircraft B64D27/16) - B64U 30/26: Ducted or shrouded rotors - B64U 50/12: using turbine engines, e.g. turbojets or turbofans - B64U 50/19: using electrically powered motors - B64C 27/08: with two or more rotors - B64C 29/0033: {the propellers being tiltable relative to the fuselage} - B64D 27/026: {comprising different types of power plants, e.g. combination of a piston engine and a gas-turbine (Hybrid electric aircraft B64D27/33)} - B64U 10/14: with four distinct rotor axes, e.g. quadcopters - B64U 10/16: with five or more distinct rotor axes, e.g. octocopters - B64C: AEROPLANES; HELICOPTERS - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT - B64U: UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR ## Abstract A propulsion assembly for a rotorcraft includes a blade assembly, a drive shaft coupled to the blade assembly and an electric motor coupled to the drive shaft and operable to provide rotational energy to the drive shaft to rotate the blade assembly. The propulsion assembly includes a landing assistance turbine coupled to the drive shaft and operable to selectively provide rotational energy to the drive shaft during an underpowered descent to rotate the blade assembly and provide upward thrust, thereby reducing a descent rate of the rotorcraft prior to landing. ## Claims ### Claim 1 A propulsion assembly for a rotorcraft, the propulsion assembly comprising: a blade assembly; a drive shaft coupled to the blade assembly; an electric motor coupled to the drive shaft and operable to provide rotational energy to the drive shaft to rotate the blade assembly; and a landing assistance turbine including a solid fuel chamber adapted to contain a solid fuel, an oxidant chamber adapted to contain an oxidant and a throttle operable to selectively release the oxidant for combustion with the solid fuel, the landing assistance turbine coupled to the drive shaft and operable to selectively provide rotational energy to the drive shaft during an underpowered descent to rotate the blade assembly and provide upward thrust, thereby reducing a descent rate of the rotorcraft prior to landing. ### Claim 2 (depends on 1) The propulsion assembly as recited in claim 1 wherein the blade assembly further comprises a fan blade assembly including a plurality of fixed pitch fan blades. ### Claim 3 (depends on 1) The propulsion assembly as recited in claim 1 wherein the blade assembly further comprises a rotor blade assembly including a plurality of variable pitch rotor blades. ### Claim 4 (depends on 1) The propulsion assembly as recited in claim 1 wherein the electric motor is interposed between the blade assembly and the landing assistance turbine, the electric motor and the landing assistance turbine forming a stacked arrangement. ### Claim 5 (depends on 1) The propulsion assembly as recited in claim 1 wherein the landing assistance turbine further comprises a single use landing assistance turbine. ### Claim 6 (depends on 1) The propulsion assembly as recited in claim 1 wherein the landing assistance turbine is adapted to provide the upward thrust for a duration between 1 and 10 seconds. ### Claim 7 (depends on 1) The propulsion assembly as recited in claim 1 wherein the drive shaft further comprises a clutch interposed between the electric motor and the landing assistance turbine. ### Claim 8 (depends on 1) The propulsion assembly as recited in claim 1 wherein the solid fuel and the oxidant are replaceable after use. ### Claim 9 (depends on 1) The propulsion assembly as recited in claim 1 wherein the throttle is operable to vary the release of oxidant in response to input from a flight control computer. ### Claim 10 (depends on 1) The propulsion assembly as recited in claim 1 wherein the throttle is operable to vary the release of oxidant in response to input from a pilot of the rotorcraft. ### Claim 11 (depends on 1) The propulsion assembly as recited in claim 1 wherein the underpowered descent of the rotorcraft is caused by at least partial failure of the electric motor. ### Claim 12 (depends on 1) The propulsion assembly as recited in claim 1 wherein the landing assistance turbine further comprises a combustion chamber to contain a combustion reaction, the combustion reaction producing exhaust and wherein the landing assistance turbine further comprises an exhaust subsystem to release the exhaust. ### Claim 13 (depends on 1) The propulsion assembly as recited in claim 1 further comprising a nacelle at least partially containing the drive shaft, the electric motor and the landing assistance turbine. ### Claim 14 A rotorcraft comprising: a fuselage; and a plurality of propulsion assemblies coupled to the fuselage, each propulsion assembly including: a blade assembly; a drive shaft coupled to the blade assembly; an electric motor coupled to the drive shaft and operable to provide rotational energy to the drive shaft to rotate the blade assembly; and a landing assistance turbine including a solid fuel chamber adapted to contain a solid fuel, an oxidant chamber adapted to contain an oxidant and a throttle operable to selectively release the oxidant for combustion with the solid fuel, the landing assistance turbine coupled to the drive shaft and operable to selectively provide rotational energy to the drive shaft during an underpowered descent to rotate the blade assembly and provide upward thrust, thereby reducing a descent rate of the rotorcraft prior to landing. ### Claim 15 (depends on 14) The rotorcraft as recited in claim 14 wherein at least one of the plurality of propulsion assemblies is subject to a malfunction caused by a failure of the electric motor; wherein the non-malfunctioning propulsion assemblies in the plurality of propulsion assemblies provide upward thrust during the underpowered descent; and wherein the landing assistance turbine of the malfunctioning propulsion assembly is adapted to provide upward thrust during a descent rate reduction maneuver prior to landing to safely land the rotorcraft. ### Claim 16 (depends on 14) The rotorcraft as recited in claim 14 wherein the rotorcraft is a quadcopter. ### Claim 17 (depends on 14) The rotorcraft as recited in claim 14 further comprising one or more wings supported by the fuselage. ### Claim 18 (depends on 14) The rotorcraft as recited in claim 14 further comprising a closed wing supported by the fuselage. ### Claim 19 (depends on 14) The rotorcraft as recited in claim 14 wherein each of the propulsion assemblies is a ducted fan assembly. ### Claim 20 (depends on 14) The rotorcraft as recited in claim 14 wherein the rotorcraft is a tiltrotor aircraft.