Staggerwing Aircraft Rotor Configuration for Hover Power Optimization
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Solution Overview
Problem
Current aircraft designs face challenges in transitioning efficiently between thrust-borne lift for VTOL and wing-borne lift for biplane orientation, particularly in achieving optimal rotor disk area and power efficiency, which affects hover power and payload capacity.
Innovation Solution
The aircraft features a staggerwing configuration with laterally and longitudinally offset rotors, a distributed thrust array, and a flight control system that independently controls each propulsion assembly, allowing for increased rotor radius and reduced interference, thereby optimizing VTOL power and enabling efficient transitions between flight modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional aircraft designs are used for VTOL operations, then the aircraft can achieve vertical takeoff and landing, but the hover power requirement is high and payload capacity is limited
Solution Approach 1:
The patent applies dimensionality change by transitioning from a single-plane rotor configuration to a three-dimensional distributed rotor array. The rotors are arranged in multiple planes along the spanwise direction, creating a volumetric thrust distribution rather than a planar one. This 3D arrangement increases the total rotor disk area without proportionally increasing power consumption, thereby reducing disk loading and hover power requirements while freeing up payload capacity.
Solution Approach 2:
The propulsion system is segmented into multiple independent rotor assemblies distributed across the wing span. Instead of using a single large rotor or a few concentrated rotors, the system divides the thrust generation into numerous smaller rotor units. Each rotor can be independently controlled, and their collective arrangement in multiple planes creates a distributed thrust array that optimizes hover efficiency and reduces the power-to-payload ratio.
2Power
If rotor radius is increased to reduce hover power, then rotor efficiency improves, but rotor interference increases
Solution Approach 1:
The patent resolves rotor interference by moving from a two-dimensional rotor plane to a three-dimensional rotor array. Rotors are distributed across multiple spanwise planes, spacing them vertically and horizontally to minimize aerodynamic interference between adjacent rotors. This 3D distribution allows each rotor to operate in a relatively undisturbed airflow environment while maintaining a compact overall configuration.
Solution Approach 2:
The rotor array employs asymmetric positioning in the spanwise direction, with rotors arranged at different lateral positions across multiple planes. This asymmetric distribution optimizes the spacing between rotors to reduce wake interaction and interference effects, while still achieving the desired total rotor disk area for efficient hover operation.
3Power
If distributed thrust array with multiple propulsion assemblies is used, then VTOL power is optimized, but device complexity increases
Solution Approach 1:
Each propulsion assembly in the distributed array is designed as a universal, multi-functional unit that can operate independently for VTOL hover, contribute to forward flight thrust, and provide redundancy. The standardized design of each assembly reduces overall system complexity despite the large number of units, as they can be manufactured, maintained, and controlled using common procedures and components.
Solution Approach 2:
The distributed propulsion system incorporates independent control of each rotor assembly, allowing localized adjustments and self-regulation. Each propulsion unit can autonomously manage its own thrust output based on flight conditions, reducing the complexity of centralized control systems and enabling modular fault isolation and self-diagnosis capabilities.
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 configuration enhances rotor efficiency, reduces hover power demand, increases payload capacity, and extends range by optimizing VTOL operations and transitioning between thrust-borne and wing-borne lift modes.
Implementation Method 1
vertically distributed rotors configured to generate thrust in a thrust-borne lift orientation
Implementation Method 2
capable of transitioning to a biplane orientation and generating wing-borne lift
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1F
AI summary
An aircraft (10) operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft (10) includes an airframe (12) having first (14) and second (16) wings in a staggerwing configuration with first and second swept pylons (18, 20) extending therebetween. A distributed thrust array is attached to the airframe (12). The thrust array includes a first plurality of propulsion assemblies (34a, 34b) coupled to the first wing (14) and a second plurality of propulsion assemblies (34c, 34d) coupled to the second wing (16). A flight control system (30) is coupled to the airframe (12) and is configured to independently control each of the propulsion assemblies (34a, 34b, 34c, 34d). The first plurality of propulsion assemblies (34a, 34b) is longitudinally offset relative to the second plurality of propulsion assemblies (34c, 34d) such that rotors of the first plurality of propulsion assemblies (34a, 34b) rotate in a different plane than rotors of the second plurality of propulsion assemblies (34c, 34d).