Helicopter Tail Rotor Speed Control Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Helicopter tail rotors operate at high speeds, posing hazards to crews and bystanders, generating excessive noise that complicates military operations and noise pollution, and current designs lack independent speed adjustment capabilities.
Innovation Solution
A speed control assembly using epicyclic or planetary gear subassemblies with a rotatable ring gear and a fixed sun gear, allowing independent adjustment of the tail rotor speed relative to the primary rotor, and incorporating a counter-rotation device to manage noise by adjusting the drive speed ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tail rotor speed is increased to improve maneuverability and control, then the helicopter's responsiveness is improved, but the safety hazard to crews and bystanders increases
Solution Approach 1:
The patent implements a variable speed control system that allows the tail rotor speed to be dynamically adjusted based on operational conditions. The system transitions from a fixed-speed design to one where the rotational speed can be modified in real-time, enabling high speeds during flight for maneuverability and reduced speeds during ground operations for safety.
Solution Approach 2:
The patent changes the operational parameter of tail rotor speed from a fixed value to a variable parameter. By implementing a controllable speed adjustment mechanism, the system can modify the rotational speed parameter to match different operational requirements, thereby resolving the contradiction between needing high speed for control and low speed for safety.
2Ease of operation
If the tail rotor speed is increased to maintain control authority, then the helicopter's responsiveness is improved, but the noise generation increases
Solution Approach 1:
The patent implements a dynamic speed control system that adjusts tail rotor speed based on operational phase. During flight, higher speeds maintain control authority, while during ground operations, reduced speeds minimize noise pollution. This dynamic adjustment resolves the contradiction between control requirements and noise generation.
3Device complexity
If a fixed gear ratio is used to simplify the transmission system, then the device complexity is reduced, but the ability to independently adjust tail rotor speed is lost
Solution Approach 1:
The patent segments the transmission system into multiple independent controllable elements. Instead of a single fixed gear ratio, the system uses separate control mechanisms for the main rotor and tail rotor, allowing independent speed adjustment. This segmentation enables versatility while keeping each individual component relatively simple.
Solution Approach 2:
The patent creates a transmission system that serves multiple functions: it transmits power from the engine to both rotors while independently controlling their speeds. The universal power transmission design allows the same engine output to drive both rotors at different speeds, providing adaptability without requiring separate engines or overly complex mechanisms.
4Object-generated harmful factors
If the tail rotor speed is reduced to decrease noise pollution, then the environmental impact is reduced, but the helicopter's maneuverability deteriorates
Solution Approach 1:
The patent implements a dynamic speed control system that adjusts tail rotor speed based on operational phase. During flight, higher speeds maintain control authority, while during ground operations, reduced speeds minimize noise pollution. This dynamic adjustment resolves the contradiction between control requirements and noise generation.
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
Enables safe reduction of tail rotor speed and noise levels independently of the primary rotor, improving operational safety and reducing noise pollution across varying altitudes without compromising maneuverability.
Implementation Method 1
A speed control assembly may be used to rotate an auxiliary rotor of a propulsion system. The speed control assembly may include an input drive shaft coupled to a first epicyclic or planetary gear subassembly, a second epicyclic or planetary gear subassembly coupled an output drive shaft, and a linkage coupling the first epicyclic or planetary gear subassembly to the second epicyclic or planetary gear subassembly.
Data Source
AI summary
A speed control assembly includes an input drive shaft coupled to a first gear subassembly having a rotatable gear, a second gear subassembly coupled to an output drive shaft, and a linkage coupling the first and second gear subassemblies, wherein the input drive shaft, the first and second gear subassemblies, and the linkage are configured such that a rotational speed of the rotatable gear adjusts a ratio of a rotational speed of the output drive shaft to a rotational speed of the output drive shaft. In some embodiments, the first gear subassembly includes a sun gear coupled to the input drive shaft, one or more planet gears, and a ring gear as the rotatable gear. In some embodiments, the second gear subassembly includes a sun gear coupled to the output drive shaft, one or more planet gears, and a fixed ring gear.