Nose Landing Gear Yoke and Breaker Bar for Precise Tire Alignment
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Solution Overview
Problem
The existing methods for aligning the nose landing gear of the F-35 aircraft are cumbersome due to the large size and weight of the tow bar, requiring multiple personnel and prone to errors, which can lead to misalignment and safety issues.
Innovation Solution
A tire alignment tool comprising an elongate breaker bar, a yoke with trunnions fitting into the landing gear gudgeons, and an index to align the collar notch, allowing for precise azimuth adjustment with a single person.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two leg tow bar is used to align the nose landing gear, then the alignment function is achieved, but the device becomes heavy and difficult to operate
Solution Approach 1:
The alignment tool is divided into separate components: a yoke assembly with trunnions that interfaces with the landing gear gudgeons, and a breaker bar that applies force. This segmentation allows each component to be optimized independently, reducing overall weight while maintaining alignment functionality.
Solution Approach 2:
The yoke assembly acts as an intermediary between the breaker bar and the landing gear. Instead of directly applying force to the landing gear, the breaker bar applies force to the yoke, which then translates this force through the trunnions to rotate the landing gear azimuthally. This intermediary mechanism provides mechanical advantage and reduces the weight required in the breaker bar.
2Ease of operation
If a two person crew is used for alignment, then the heavy tow bar can be manipulated, but the process becomes complex and prone to errors
Solution Approach 1:
The alignment tool incorporates a visual index that automatically indicates when the landing gear is properly aligned. The index aligns with a reference mark on the aircraft fuselage when the landing gear azimuth is correct, providing self-verifying alignment without requiring multiple personnel to coordinate and communicate.
Solution Approach 2:
The visual indexing system replaces the mechanical coordination required between multiple personnel. Instead of one person verbally directing another person's manual manipulation of a heavy tow bar, the system uses visual alignment indicators that provide immediate feedback on alignment status, reducing human error and simplifying the operational process.
3Measurement precision
If visual determination of azimuthal angle is used, then alignment can be performed, but parallax error and other errors occur
Solution Approach 1:
The visual index provides a clear, high-contrast visual indication of proper alignment. When the index aligns with the reference mark on the aircraft fuselage, it creates an unambiguous visual signal that eliminates parallax errors and subjective judgment calls associated with traditional visual alignment methods.
Data Source
AI summary
A yoke and breaker bar for aligning the nose landing gear tire of an F-35 aircraft. The F-35 landing gear has a fixed forward notch which is used to align the landing gear and tire with the centerline of the airframe. The yoke is removably attached to the landing gear through a pair of matched trunnion and gudgeons. Torque may then be applied to the yoke through the breaker bar to adjust the azimuthal angle of the landing gear. An index is joined to the yoke or breaker bar for aligning the landing gear with the fixed notch. The index may be a laser beam, an elongate pointer or combination thereof.