Rotatable Propeller Blades as Slats for Quiet Flight
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Solution Overview
Problem
Conventional aircraft with Handley-Page slats face weight and complexity issues due to additional components, and tilting propellers do not improve wing airfoil shape during take-off and landing.
Innovation Solution
The integration of rotatable propeller blades with an airfoil shape that lock parallel to the wing leading edge during take-off and landing, and unlock for flight, serving as both propellers and Handley-Page slats, eliminating the need for conventional slats and reducing noise by rotating slower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional Handley-Page slats are added to improve airflow during take-off and landing, then lift is improved, but weight and device complexity increase
Solution Approach 1:
The propeller blades are designed to serve dual functions: acting as Handley-Page slats during take-off and landing to improve lift, and rotating during flight to provide propulsion. This multi-functionality eliminates the need for separate slat mechanisms, reducing weight and structural complexity while maintaining the lift enhancement benefit.
2Force
If Handley-Page slats are added to improve airflow, then lift is improved, but the aircraft requires additional mechanisms for slat retraction and extension
Solution Approach 1:
The propeller blades automatically transition between slat and propulsion functions based on operational phase. During take-off and landing, the blades are positioned to act as fixed slats for lift enhancement. During flight, the blades rotate to provide thrust. This automatic transition eliminates complex mechanical retraction and extension mechanisms required by conventional slat systems.
3Power
If propellers rotate faster to maintain thrust during flight, then propulsion is improved, but noise increases
Solution Approach 1:
The propeller rotation speed parameter is optimized to operate at lower RPM compared to conventional propellers. The dual-function design allows the propeller to maintain effective thrust at reduced speeds because the blades are positioned to act as slats during low-speed operations (take-off and landing), providing aerodynamic lift enhancement that compensates for reduced propulsive efficiency.
4Length of stationary object
If the V-22 Osprey tilts engines and propellers to avoid ground clearance issues, then ground clearance is improved, but no improvement to wing airfoil shape is obtained
Solution Approach 1:
Instead of tilting the entire engine and propeller assembly, the invention keeps the propeller in a fixed position on the wing but enables the blades to rotate between horizontal (slat) and rotational (propulsion) orientations. This maintains the wing's airfoil shape and lift capability during take-off and landing while providing adequate ground clearance through the propeller's compact radial design.
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 design enhances lift and reduces noise and complexity by using dual-purpose blades that act as slats during take-off and landing, simplifying assembly and operation while maintaining thrust during flight, and reduces the need for mechanical slat retraction and extension.
Implementation Method 1
Each blade has an airfoil shape and a locked condition during take-off and landing of the aircraft extending parallel to a leading edge of the wing
Implementation Method 2
at least one blade rotatably connected to each mounting member and has an airfoil shape. The at least one blade is in a locked condition during take-off and landing of the aircraft extending parallel to a leading edge of the wing and in an unlocked, rotating condition during flight for propelling the aircraft
Data Source
AI summary
A propeller for an aircraft having a fuselage and a pair of fixed wings includes a mounting member secured to at least one wing. At least one blade is rotatably connected to each mounting member and has an airfoil shape. The at least one blade is in a locked condition during take-off and landing of the aircraft extending parallel to a leading edge of the wing and in an unlocked, rotating condition during flight for propelling the aircraft.