Pitch Angle Blocking Device for Rotary-Wing Aircraft
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Solution Overview
Problem
Existing pitch angle blocking devices for rotary-wing aircraft are costly, heavy, and decrease in-flight fuel efficiency, as they require additional equipment that remains operational even when the aircraft is not in use, leading to potential damage from torque moments during blade folding.
Innovation Solution
A pitch angle blocking device comprising attachment means on adjacent rotor blades connected by a connecting device that non-rotatably links them, allowing for external installation without adding weight to the aircraft, and can be applied while the hydraulic system is active, using brackets, struts, and fasteners to constrain pitch angles and prevent undesired movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active pitch adjustment devices with hydraulic actuators are used to control rotor blades, then pitch angle control precision is improved, but device weight and complexity increase
Solution Approach 1:
The patent extracts the pitch angle blocking function from the complex active pitch adjustment system. Instead of using hydraulic actuators and control rods, the invention uses a separate, simple blocking device with pins that engage with holes in the rotor blade to fix pitch angles, eliminating the need for heavy active control components while maintaining pitch angle control capability
Solution Approach 2:
The blocking device uses simple, inexpensive components such as pins, clips, or latches that can be easily installed and removed. These blocking elements are much simpler and lighter than hydraulic actuators, providing the necessary pitch angle fixation without the weight and complexity of active control systems
2Reliability
If pitch angle blocking devices remain installed on the aircraft, then rotor blade protection is improved, but in-flight fuel efficiency decreases
Solution Approach 1:
The blocking device is designed to be dynamically configurable - it can be installed when the aircraft is on the ground for storage or maintenance, and removed when the aircraft needs to fly. This dynamic deployment ensures rotor blade protection is provided only when needed, eliminating any negative impact on flight performance
Solution Approach 2:
The blocking device is installed and removed periodically based on operational requirements - installed during ground operations for blade protection, removed before flight. This periodic deployment pattern ensures protection is provided during non-flight periods without affecting flight fuel efficiency
3Volume of moving object
If rotor blades are folded during non-operational mode, then storage space is improved, but torque moments cause damage to pitch adjustment devices
Solution Approach 1:
The blocking device is installed on the rotor blades before folding operations begin. This preliminary action prevents unwanted pitch angle changes during the folding process, protecting the pitch adjustment devices from damaging torque moments that would occur if the blades were allowed to move freely
Solution Approach 2:
The blocking device applies a counter-action to the gravitational and inertial forces that cause unwanted pitch angle changes during folding. By mechanically constraining the pitch angle with pins or clips, the device prevents the development of damaging torque moments on the pitch adjustment system
Data Source
AI summary
A pitch angle blocking device for blocking the pitch angle of a multi-blade rotor that has neighboring first and second rotor blades in circumferential direction that extend from a rotor hub of a rotary-wing aircraft In non-operational mode of the rotary-wing aircraft. The present embodiments further relate to a multi-blade rotor of a rotary-wing aircraft that is adapted to receiving such a pitch angle blocking device, and to a rotary-wing aircraft with such a multi-blade rotor. The pitch angle blocking device comprises first and second attachment means that are configured to be non-rotatably and releasably attached to the first and second rotor blades spaced apart from the rotor hub, and a connecting device that non-rotatably connects the first attachment means with the second attachment means.