Distributed Propulsion Assemblies for VTOL Forward Flight Transition
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Solution Overview
Problem
Current aircraft designs, such as fixed-wing, tiltrotor, and tiltwing, face challenges in transitioning efficiently between vertical takeoff and landing (VTOL) and forward flight modes, particularly in terms of control complexity and downwash inefficiencies, which limit their versatility and operational range.
Innovation Solution
The aircraft features a distributed propulsion system with independently controlled propulsion assemblies and a flight control system that allows for seamless transitions between VTOL and forward flight modes by maintaining a pod assembly in a generally horizontal attitude, enabling vertical takeoff, hovering, and efficient forward flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If tiltrotor aircraft use fixed wing during vertical takeoff and landing, then forward thrust is provided, but downwash inefficiencies occur due to interference from the fixed wing
Solution Approach 1:
The aircraft separates the functions of vertical lift and forward thrust into distinct propulsion assemblies. During vertical takeoff and landing, only the vertical lift assemblies are active, eliminating the fixed wing from the downwash path and resolving the energy loss issue while maintaining forward thrust capability through the horizontal flight phase.
Solution Approach 2:
The aircraft uses dynamically reconfigurable propulsion assemblies that can change orientation and function. The proprotors can rotate between vertical and horizontal positions, allowing the system to optimize performance for each flight phase: vertical lift during VTOL, and forward thrust during horizontal flight, eliminating the fixed wing interference problem.
2Power
If tiltwing aircraft rotate wing to vertical orientation for VTOL, then vertical thrust efficiency improves, but control complexity increases during hover due to large surface area for crosswinds
Solution Approach 1:
The aircraft divides the propulsion system into multiple independent assemblies: vertical lift assemblies for VTOL operations and horizontal flight assemblies for forward flight. This segmentation eliminates the need for a large rotating wing surface during hover, thereby reducing control complexity while maintaining vertical thrust efficiency through the dedicated vertical lift assemblies.
Solution Approach 2:
The propulsion assemblies dynamically reconfigure their orientation based on flight phase. During hover and VTOL, the vertical lift assemblies operate in a fixed vertical position optimized for lift generation, avoiding the control issues of rotating large wing surfaces. The system transitions to horizontal orientation only when needed for forward flight, simplifying control during each specific phase.
3Adaptability or versatility
If aircraft transition between VTOL and forward flight modes, then versatility is improved, but control complexity increases during transitions
Solution Approach 1:
The aircraft segments the propulsion system into independent vertical lift and horizontal flight assemblies, each optimized for specific flight phases. During transitions, the system can selectively activate or deactivate specific assemblies rather than managing complex rotations of entire wing structures, thereby maintaining versatility while reducing control complexity during mode changes.
Solution Approach 2:
The propulsion assemblies perform dynamic reconfiguration during transitions, rotating from vertical to horizontal orientation (or vice versa) as needed. This dynamic capability allows the aircraft to adapt between VTOL and forward flight modes while the flight control system manages the transitions systematically, reducing overall control complexity compared to managing large rotating wing surfaces.
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
This solution enhances the aircraft's versatility and operational efficiency by simplifying control during transitions and reducing downwash inefficiencies, allowing for safe and efficient transportation of passengers or cargo in various environments.
Implementation Method 1
a propulsion system attached to the airframe... enabling the flying frame to have a vertical takeoff and landing mode and a forward flight mode
Implementation Method 2
a flight control system operably associated with the propulsion system wherein... independently controlled by the flight control system, thereby enabling the flying frame to have a vertical takeoff and landing mode and a forward flight mode
Data Source
AI summary
In some embodiments, an aircraft includes a flying frame having an airframe with first and second wing members having a plurality of pylons extending therebetween, a distributed propulsion system including a plurality of propulsion assemblies securably attached to the airframe and a flight control system operably associated with the distributed propulsion system. The flying frame has a vertical takeoff and landing mode with the wing members disposed in generally the same horizontal plane and a forward flight mode with the wing members disposed in generally the same vertical plane. The flight control system is operable to command the propulsion assemblies responsive to at least one of remote flight control, autonomous flight control and combinations thereof.