Two-axis Gimbal Propulsion for Aircraft Thrust Vectoring
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Solution Overview
Problem
Current VTOL aircraft face challenges in efficient vertical takeoff and landing due to downwash inefficiencies and control difficulties, particularly in tiltrotor and tiltwing designs, which affect their versatility and operational capabilities.
Innovation Solution
A propulsion assembly with a gimbal system that tilts about two axes, allowing for independent control of thrust vectors, enabling efficient thrust vectoring and improved control during hover and forward flight, and a distributed thrust array with multiple propulsion assemblies for enhanced maneuverability and redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If tiltrotor aircraft use fixed wing for forward flight with proprotors providing thrust, then forward speed and range are improved, but downwash inefficiencies occur during vertical takeoff and landing due to interference from the fixed wing
Solution Approach 1:
The aircraft is divided into separate functional components: a movable wing assembly that can be positioned independently from the proprotors. During vertical flight, the wing is segmented away from the propeller downwash path, eliminating interference. During forward flight, the wing is repositioned to generate lift while proprotors provide thrust, maintaining speed performance without downwash losses.
Solution Approach 2:
The wing assembly is made dynamically reconfigurable through movable mounting mechanisms that allow it to change position relative to the proprotors. The wing can transition between a forward position for efficient forward flight and a retracted position that clears the propeller downwash during vertical operations, optimizing performance across different flight regimes.
2Loss of energy
If tiltwing aircraft rotate the wing to vertical orientation for VTOL, then vertical thrust efficiency is improved, but control during hover becomes difficult requiring additional control mechanisms
Solution Approach 1:
The control system is segmented into multiple independent mechanisms: the movable wing assembly provides primary pitch and roll control through its repositioning capability, while separate cyclic rotor control mechanisms provide additional hover control authority. This segmentation allows efficient vertical thrust from the tilted wing while maintaining ease of hover control through redundant control inputs.
Solution Approach 2:
The movable wing assembly serves multiple functions: it generates lift during forward flight, provides vertical thrust support during hover when tilted, and acts as a primary control surface for pitch and roll. This multi-functionality reduces the need for additional dedicated control mechanisms while maintaining hover control capability.
3Adaptability or versatility
If helicopters use rotors for vertical lift and forward flight, then VTOL capability and maneuverability are improved, but forward airspeed is limited compared to fixed-wing aircraft
Solution Approach 1:
The proprotors are designed to perform multiple functions: they provide vertical lift during hover and takeoff, transition to providing forward thrust during forward flight, and can be tilted to optimize performance in each regime. This multi-functionality allows the aircraft to achieve both VTOL capability and high forward airspeed without requiring separate systems for each function.
Solution Approach 2:
The proprotors are mounted on movable nacelles that can dynamically change orientation from horizontal (for vertical flight) to vertical (for forward flight). This dynamic reconfiguration allows the same propulsion system to optimize for both VTOL operations and high-speed forward flight, achieving versatility and speed performance that neither configuration alone could provide.
4Speed
If fixed-wing aircraft use wings for lift generation, then forward airspeed and range are improved, but runway length requirement increases to hundreds or thousands of feet
Solution Approach 1:
The lift and propulsion functions are segmented into separate systems: the movable wing assembly provides lift during forward flight, while the proprotors provide both vertical thrust for takeoff/landing and forward thrust for cruise. This segmentation allows the aircraft to use vertical lift from proprotors for takeoff and landing, eliminating the need for long runways, while maintaining efficient wing-borne forward flight capability.
Solution Approach 2:
The aircraft employs dynamic reconfiguration of the wing and proprotor positions to transition between vertical and forward flight modes. During takeoff and landing, the proprotors are positioned to provide vertical lift, enabling short-field operations. During forward flight, the wing is positioned to generate lift efficiently, maintaining high speed and range performance without requiring long runways.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient vertical takeoff and landing, improved control during hover, and enhanced forward flight capabilities, increasing the aircraft's versatility and operational flexibility while providing redundant directional control for safety and fault tolerance.
Implementation Method 1
The rotor assembly is rotatable with the output drive of the electric motor in a rotational plane to generate thrust having a thrust vector with a direction
Implementation Method 2
A propulsion assembly with a gimbal system that tilts about two axes, allowing for independent control of thrust vectors
Data Source
AI summary
A propulsion assembly for an aircraft includes a housing having a gimbal coupled thereto that is operable to tilt about first and second axes. A propulsion system is coupled to and operable to tilt with the gimbal. The propulsion system includes an electric motor having an output drive and a rotor assembly having a plurality of rotor blades. The rotor assembly is rotatable with the output drive of the electric motor in a rotational plane to generate thrust having a thrust vector with a direction. The first axis of the gimbal is orthogonal to the second axis of the gimbal. Actuation of the gimbal tilts the propulsion system relative to the housing to change the rotational plane of the rotor assembly relative to the housing, thereby controlling the direction of the thrust vector within a thrust vector cone.