Tiltable Wing in Propulsion Wake for VTOL Lift
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Solution Overview
Problem
Existing aircraft face challenges in generating sufficient lift without increasing size, weight, or drag, particularly in VTOL and STOL operations, as traditional methods like increasing wingspan or angle of attack lead to performance compromises.
Innovation Solution
The design incorporates a tiltable wing mounted in the wake of a propulsion unit, which can tilt to vary its angle of attack, utilizing active flow control and multiple propulsion units to enhance lift generation while minimizing size and weight, and reducing drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the wingspan of the aircraft is increased to generate more lift, then the lift force is improved, but the size and weight of the aircraft are increased
Solution Approach 1:
The wing is made tiltable to dynamically adjust the angle of attack. During vertical takeoff and landing, the wing tilts to a high angle of attack (e.g., 20-40 degrees) to maximize lift generation from the propeller wake. During horizontal flight, the wing returns to a low angle of attack to minimize drag and maintain efficient forward flight performance.
Solution Approach 2:
The angle of attack parameter is dynamically changed by tilting the wing. This allows the same wing structure to operate at different lift coefficients depending on the flight regime, eliminating the need for a larger wingspan to achieve vertical lift capability.
2Force
If the thickness of the wings is increased to generate more lift, then the lift force is improved, but the drag effect on the aircraft during forward flight is increased
Solution Approach 1:
Instead of increasing wing thickness statically, the invention dynamically adjusts the angle of attack by tilting the entire wing assembly. This allows high lift coefficients to be achieved during VTOL operations without permanently increasing the wing's cross-sectional area, thereby avoiding increased parasitic drag during forward flight.
3Force
If the fixed angle of attack of the wings is increased to generate more lift, then the lift force is improved, but the drag effect on the aircraft during forward flight is increased
Solution Approach 1:
The wing angle of attack is made variable through the tilting mechanism. During vertical operations, the wing is tilted to a high angle of attack to maximize lift from the propeller downwash. During horizontal flight, the wing returns to a low angle of attack (near zero), minimizing both induced drag and parasitic drag, thus resolving the contradiction between lift generation and drag reduction.
4Weight of stationary object
If the wingspan of tilt-rotor aircraft is shortened to reduce size and weight, then the aircraft size and weight are reduced, but the lift provided by the wings is reduced
Solution Approach 1:
The invention uses a tiltable wing configuration where the wing can be rotated to a high angle of attack position. This dynamic adjustment allows a shorter wingspan to generate sufficient lift during vertical operations by maximizing the angle of attack, eliminating the need for long wingspan tilt-rotor configurations.
Solution Approach 2:
The propeller wake serves as an intermediary that provides concentrated airflow to the tiltable wing during vertical operations. By positioning the wing in the propeller wake and tilting it to a high angle of attack, the concentrated airflow generates sufficient lift from a shorter wingspan, acting as a mediator between the propulsion system and the lift-generating surface.
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 allows for increased lift and reduced drag, enabling vertical take-off and landing with shorter runways, improved horizontal flight performance, and reduced overall aircraft size and weight, while avoiding the complexity of tilting propulsion units.
Implementation Method 1
The tiltable wing is disposed in the wake from the propulsion unit and arranged to tilt to vary the angle of attack of the tiltable wing
Implementation Method 2
A fixed wing aircraft typically comprises one or more propulsion systems configured to provide horizontal thrust to cause forward movement of the aircraft
Data Source
AI summary
The present invention relates to an aircraft. The aircraft comprises a fuselage, a propulsion mounting spar, a propulsion unit, and a tillable wing. The propulsion unit is mounted to the fuselage by the propulsion mounting spar. The ti liable wing is spaced apart from the propulsion mounting spar. The tillable wing is disposed in the wake from the propulsion unit. The tillable wing is arranged to tilt to vary the angle of attack of the tillable wing. In use, the propulsion unit forces air over the tillable wing such that lift is generated by the wing. The angle of attack of the wing can be increased by tilting the wing to increase the amount of lift generated by the wing. The aircraft may be configured for vertical take-off and/or landing (VTOL), or short take-off and/or landing (STOL).