Propeller Vane Pitch Control with Geometric Failsafe Retention
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Solution Overview
Problem
Current technologies for controlling the pitch of propeller vanes in aircraft turbine engines are complex, expensive, and lack a reliable failsafe mechanism to prevent vane detachment and impact on the aircraft fuselage.
Innovation Solution
A pitch control system for propeller vanes that includes a vane with a blade connected to a root, a hub with an annular wall, a ring with a perforated intermediate wall, abutments engaged in openings, and a nut that secures the assembly, providing radial preload and a failsafe mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If current technologies for controlling pitch are used, then the propeller can change pitch angle to adapt thrust, but the system becomes complex and expensive without reliable failsafe mechanism
Solution Approach 1:
The pitch control system is divided into modular components: a pitch control unit with motor and driver, separate abutment elements, and a hub assembly. This segmentation allows independent optimization of each component and simplifies maintenance while maintaining full pitch adaptation capability across the flight domain.
Solution Approach 2:
Abutment elements are introduced as intermediary components between the pitch control unit and the vane root. These abutments transmit the pitch control forces while providing a failsafe mechanism through their geometric engagement, reducing the complexity of the overall control system while ensuring reliability.
2Strength
If current retention technologies are used, then the vane can be attached to the hub, but the system lacks failsafe mechanism to prevent vane detachment on failure
Solution Approach 1:
The abutment elements are designed with geometric features that provide inherent failsafe protection. If the primary retention mechanism fails, the abutments' shape and positioning ensure the vane remains retained through passive geometric constraint, providing beforehand protection against catastrophic detachment without requiring active monitoring systems.
Solution Approach 2:
The hub assembly incorporates localized reinforcement features and specific geometric configurations at the vane root engagement area. This local quality enhancement provides both strong retention capability and inherent failsafe properties through the tailored geometry of the hub and abutment interfaces.
3Reliability
If larger and denser elements are used in control systems, then the failsafe function is improved, but the mass of the aircraft increases impacting performance
Solution Approach 1:
The abutment elements are designed to be self-retaining through their geometric configuration. The failsafe function is achieved through the inherent shape and engagement features of the abutments themselves, eliminating the need for additional heavy shielding or reinforcement structures, thus maintaining aircraft performance while ensuring reliability.
Solution Approach 2:
The design optimizes the geometric parameters of the abutment elements and hub interface to achieve maximum retention and failsafe capability with minimal mass. By carefully selecting and optimizing dimensional parameters, the system achieves reliable failsafe function without requiring oversized components that would increase aircraft weight.
4Reliability
If the vane is securely retained during operation, then the risk of impact on fuselage is reduced, but the assembly and disassembly process becomes complex
Solution Approach 1:
The vane assembly is segmented into the vane root, abutment elements, and hub components. This segmentation allows for simple modular assembly and disassembly operations while maintaining secure retention during operation. Each component can be independently installed and removed without affecting the entire propeller assembly.
Solution Approach 2:
The abutment elements are designed with dynamic engagement features that automatically lock into place during operation to ensure secure vane retention. During assembly and disassembly, the same geometric features provide guided engagement and disengagement, simplifying the maintenance process while ensuring operational reliability.
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
The system allows for easy assembly and disassembly of the vane without disassembling the hub, provides a robust failsafe mechanism to retain the vane in case of failure, and ensures the vane is immobilized and retained during operation, reducing the risk of damage to the fuselage.
Implementation Method 1
a nut (42) screwed onto the thread (78) of the ring (38) and configured to bear axially on the hub (36) so that tightening the nut forces the lower wall (74) of the ring (38) to bear on the lower bearing surface (32a) of the bulb (32) of the root (14), the upper bearing surface (32b) of this bulb (32) to bear on the abutments (40), and these abutments (40) to bear on complementary support surfaces (60b, 64a, 68a) of the at least one housing (64, 68) of the hub (36)
Implementation Method 2
the lower bearing surface (32a) of the bulb (32) of the root (14) being configured so as to bear, at least in the axial direction, on this lower wall (74), on the side opposite the blade (12) of the vane (10)
Implementation Method 3
the upper bearing surface (32b) of the bulb (32) of the root (14) being configured so as to bear, at least in the axial direction, on these abutments (40), on the blade side of the vane (10)
Implementation Method 4
these abutments (40) to bear on complementary support surfaces (60b, 64a, 68a) of the at least one housing (64, 68) of the hub (36)
Data Source
AI summary
A system for controlling the pitch setting of a propeller blade for an aircraft turbine engine, includes a blade having a vane connected to a root. A hub accommodates the root of the blade, and a ring is mounted around the root and in the hub. Stops are also mounted around the root and in the hub. A nut is threadedly engaged with a thread of the ring and is configured to bear axially against the hub to secure the assembly.