Blade Fold Bolt Positioning for Compact Rotor Storage
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Solution Overview
Problem
Current rotor blade folding systems for rotorcraft and tiltrotor aircraft are inadequate for accommodating reduced storage space requirements, as they cannot achieve a tighter grouping of rotor blades, limiting the number of aircraft that can be stored in limited spaces.
Innovation Solution
A folding rotor blade assembly design that includes a yoke, inboard and outboard bearing assemblies, a grip, and a blade fold bolt positioned outboard of the outboard bearing housing, allowing for a more compact folding mechanism by relocating the pivot point of the rotor blades, enabling them to be folded more tightly and efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If rotor blades are folded about a single pivot point positioned outboard of the yoke, then the folding mechanism is simple, but the storage space required is too large to accommodate reduced space parameters
Solution Approach 1:
The folding mechanism is divided into multiple pivot points: an inboard pivot point connected to the yoke and an outboard pivot point for the blade fold bolt. This segmentation allows the rotor blade to fold in two stages, first at the inboard pivot and then at the outboard pivot, achieving a more compact stowed configuration that reduces storage space while maintaining mechanical simplicity through modular pivot connections
Solution Approach 2:
The folding mechanism transitions from a single-plane fold to a two-dimensional folding path by introducing both inboard and outboard pivot points. The blade first rotates in one plane about the inboard pivot, then folds in a different plane about the outboard pivot, creating a tighter grouping that reduces the overall storage footprint without significantly increasing mechanism complexity
2Area of stationary object
If the pivot point is relocated outboard of the outboard bearing housing, then the rotor blade assembly becomes more compact, but the structural complexity increases
Solution Approach 1:
The outboard pivot point structure serves multiple functions: it acts as the folding pivot point, provides structural support for the blade fold bolt, and integrates with the outboard bearing housing. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in structural complexity while achieving the compact folded configuration
Solution Approach 2:
The blade fold bolt acts as an intermediary element that connects the rotor blade to the outboard pivot point structure. It provides the necessary pivot function while distributing loads and forces, simplifying the overall structural design at the outboard pivot location and preventing excessive complexity in the folding mechanism
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 design allows for a more compact stowed position of rotorcraft, enabling a higher density of aircraft storage by reducing the overall size of the rotor blade assembly, thus accommodating more aircraft in limited space.
Implementation Method 1
an inboard beam housing an inboard centrifugal force bearing, the inboard beam connected to the yoke
Data Source
AI summary
A folding rotor blade assembly for an aircraft a yoke, an inboard beam coupled to the yoke, an inboard centrifugal force bearing coupled to the inboard beam, a grip coupled to the inboard beam, an outboard bearing housing coupled to the grip, and a rotor blade pivotally coupled to the grip by a blade fold bolt that is positioned outboard of the outboard bearing housing.