Counter-rotating Propeller Stopped Rotor Guide Vane
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Solution Overview
Problem
Counter-rotating propeller systems face inefficiencies during lower power operations, as existing technologies require separate guide vanes which add complexity and weight, and do not effectively utilize stopped blades for energy conversion.
Innovation Solution
A propeller system with a pair of rotors and blade sets, where one rotor and blade set can be selectively stopped, allowing the other to function as guide vanes by changing the pitch angle of the stopped blades to redirect airflow and convert swirling flow into thrust, eliminating the need for separate guide vanes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If separate guide vanes are added to redirect swirling flow, then energy conversion efficiency is improved, but device complexity and weight increase
Solution Approach 1:
The patent merges the guide vane function with the second blade set of the counter-rotating propeller system. When the first rotor stops rotating, its blades are repositioned to serve as guide vanes for the second rotor's swirling flow, eliminating the need for separate guide vane components and reducing system complexity while maintaining energy conversion efficiency
Solution Approach 2:
The first blade set is designed to perform multiple functions: it acts as rotating blades during high-power operation and transforms into guide vanes during low-power operation when the first rotor stops. This multi-functionality allows the same component to serve different purposes based on operational conditions, reducing the need for additional specialized components
2Loss of energy
If separate guide vanes are added to redirect swirling flow, then energy conversion efficiency is improved, but system weight increases
Solution Approach 1:
The guide vane function is combined with the existing first blade set structure, eliminating the need for separate guide vane components. This merging approach reduces the total weight of the propeller system while maintaining the ability to convert swirling flow energy into useful thrust
Solution Approach 2:
The first blade set serves dual purposes: generating thrust during rotation and guiding swirling flow when stopped. This multi-functionality eliminates the need for additional weight-bearing guide vane structures, reducing overall system weight while maintaining energy conversion capabilities
3Adaptability or versatility
If pitch change mechanism is added to stopped blades, then guide vane functionality is improved, but device complexity increases
Solution Approach 1:
The pitch change mechanism, already present in the counter-rotating propeller system for blade angle adjustment during rotation, is utilized additionally to position the stopped blades as guide vanes. This existing mechanism serves multiple functions without requiring separate control systems, maintaining adaptability while minimizing added complexity
Solution Approach 2:
The pitch change mechanism automatically adjusts the angle of incidence of the stopped blades to optimal guide vane positions based on flight conditions, allowing the system to self-optimize its configuration without requiring complex external control mechanisms
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 solution enhances thrust generation during lower power operations by converting wasted energy from swirling flows into propulsion, reducing system complexity and weight, and optimizing energy use across varying flight conditions.
Implementation Method 1
turn a swirling flow of air from said first blade set generally in an axial direction, to convert energy from the swirling flow into thrust
Implementation Method 2
convert energy from the swirling flow into thrust
Implementation Method 3
change an angle of incidence of the blade in at least one of the first and second blade sets
Data Source
Figure 1~2
Figure 3~4
AI summary
A propeller system has a pair of rotors and a pair of blade sets (24, 28) and at least one drive input to drive a first of the rotors and blade sets (24) and a second of the rotors and blade sets (28). The blade sets (24, 28) are positioned such that when both are driven, air will be driven across the first blade set (24) and then across the second blade set (28). There is a pitch change mechanism (40, 41) to change an angle of incidence of the blade in at least one blade sets (24, 28). There is a device for selectively stopping rotation of at least one of the first or second rotor and blade set (24) while still allowing rotation of the other rotor and blade set (24). The pitch change mechanism (40, 41) of the stopped blade set can still change the angle of incidence when the device has stopped rotation. A method is also disclosed.