Slewing Tail Rotor Transmission for Variable Thrust Direction
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Solution Overview
Problem
Current drive systems for tail rotors in helicopters are fixed in design, lacking the ability to implement variable geometry, which restricts enhanced flight capabilities.
Innovation Solution
A mechanical power transmission system that pivots about an axis to vary the angle between an input shaft and an output shaft, allowing the tail rotor to change its orientation, comprising an input gear, an output gear, and intermediate gears with a shaft that couples them, enabling the tail rotor to pivot and adjust its thrust direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed design drive system is used for the tail rotor, then the structure is simple and reliable, but the flight capabilities cannot be enhanced through variable geometry
Solution Approach 1:
The patent applies the dynamics principle by transforming the fixed, static drive system into a dynamic, adjustable system. The tail rotor assembly is made movable relative to the drive shaft through a pivot mechanism, allowing the orientation angle to change during flight operations. This enables the system to adapt to different flight conditions (hover, forward flight, backward flight) while maintaining structural integrity through controlled mechanical movement rather than fixed rigid connections.
Solution Approach 2:
The drive system is segmented into distinct functional components: the drive shaft, the pivot mechanism, and the tail rotor assembly. This segmentation allows independent optimization of each component and enables the pivot mechanism to serve as an adjustable interface between the fixed drive shaft and the movable tail rotor, facilitating variable geometry configurations without compromising overall system reliability.
2Adaptability or versatility
If the tail rotor orientation is fixed relative to the drive shaft, then the mechanical structure is simpler, but the ability to perform various flight operations is limited
Solution Approach 1:
The patent implements dynamics by enabling the tail rotor assembly to pivot and change its orientation angle relative to the drive shaft. This dynamic adjustment capability allows the system to optimize performance for different flight operations such as hover, forward flight, and backward flight, transforming a static mechanical structure into an adaptive system that responds to varying flight conditions.
Solution Approach 2:
The adjustable orientation mechanism provides multi-functionality by enabling the same drive system to support multiple flight operations. The tail rotor can be positioned at different angles to compensate for torque in various flight regimes, making the system universally applicable to hover, forward flight, backward flight, and other maneuvers without requiring separate dedicated systems for each operation.
Data Source
AI summary
A mechanical power transmission that pivots about an axis to vary an angle between an input shaft and an output shaft. The mechanical power transmission includes an input gear having an input shaft that couples to a drive shaft, an output gear having an output shaft that couples to a tail rotor, a first intermediate gear rotationally coupled to the input gear, and a second intermediate gear rotationally coupled to the output gear. The mechanical power transmission further comprises a shaft that mechanically couples the first intermediate gear with the second intermediate gear, where a centerline of the shaft is coincident with the axis.