Concentric Aircraft Drive Shaft Gap for Ballistic Hit Survival
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Solution Overview
Problem
Conventional drive shafts for aircraft lack sufficient structural integrity to withstand and recover from ballistic damage, compromising their ability to complete missions safely after such incidents.
Innovation Solution
A drive shaft design featuring an outer and inner shaft with a gap larger than the expected projectile cross-section, connected via sleeves and circumferential connectors, made from fiber-reinforced polymer-matrix composite or metal materials, to enhance ballistic tolerance and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-shaft drive shaft design is used, then the structure is simple and easy to manufacture, but the ballistic tolerance and structural integrity after ballistic damage are insufficient
Solution Approach 1:
The drive shaft is divided into an inner shaft and an outer shaft that are concentrically arranged with a gap between them. This segmentation allows the projectile to pass through the gap without penetrating the entire shaft structure, thereby maintaining structural integrity and rotational functionality after ballistic impact.
Solution Approach 2:
The inner shaft is nested within the outer shaft in a concentric configuration, creating a nested structure where both shafts work together to provide enhanced ballistic protection while maintaining the overall drive shaft functionality.
2Reliability
If the gap between inner and outer shafts is increased to accommodate larger projectiles, then ballistic tolerance improves, but the structural strength and rigidity may be compromised
Solution Approach 1:
By segmenting the shaft into inner and outer components with a controlled gap, the design achieves ballistic tolerance without requiring the entire shaft to bear the full impact load, thereby maintaining structural strength despite the presence of a gap.
Solution Approach 2:
The drive shaft utilizes composite material construction where the inner and outer shafts can be made from high-strength materials that maintain structural integrity while allowing for the gap design that provides ballistic protection.
3Reliability
If multiple connection methods (sleeves, connectors) are used between inner and outer shafts, then structural integrity post-ballistic damage is improved, but manufacturing complexity increases
Solution Approach 1:
The connection system is segmented into modular components including sleeves and circumferential connectors that can be independently manufactured and assembled, simplifying the overall manufacturing process while maintaining structural integrity.
Solution Approach 2:
The sleeves and connectors are pre-positioned and pre-assembled in specific configurations during manufacturing, allowing for simplified final assembly and ensuring proper structural alignment before the drive shaft is put into service.
Data Source
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AI summary
An aircraft drive shaft (100) including an outer shaft (104) having a first diameter configured to couple a first gearbox and a second gearbox to provide power transfer between the two gearboxes, an inner shaft (102) concentric with the outer shaft (104) and having a second diameter configured to provide structural support to the outer shaft, a gap (106) defined between an outer peripheral surface of the inner shaft and an inner peripheral surface of the outer shaft, wherein the gap is sized according to a ballistic projectile cross-section size that the aircraft is considered to encounter on an upcoming mission, and a sleeve (110)located at least at first end of the outer shaft (104) connecting the outer shaft (104) to the inner shaft (102).