Aircraft Ground Spoiler Drive System Wheel Lock Detection
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Solution Overview
Problem
Existing systems for automatically deploying aircraft ground spoilers fail to deploy them reliably when the aircraft's wheels are locked, particularly on slippery surfaces, which can prevent effective reduction of lift during landing.
Innovation Solution
A drive system that includes a wheel speed detecting part, an air speed detecting part, and a control unit that automatically deploys the ground spoiler based on predetermined wheel and air reference speeds, ensuring deployment even if the wheels are locked, and allows for delayed deployment of multiple spoilers to manage pitching moments and load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ground spoiler is deployed based on wheel speed detection, then the deployment is simple and reliable under normal conditions, but the system fails to deploy when the wheel is locked on slippery surfaces
Solution Approach 1:
The system changes the detection parameter from wheel speed to air speed when wheel lock is detected. By monitoring air speed instead of wheel speed, the system can reliably detect landing conditions even when the wheel is locked, ensuring the ground spoiler deploys correctly without requiring complex additional sensors or mechanisms.
Solution Approach 2:
The system uses feedback from both wheel speed sensors and air speed sensors to determine deployment conditions. When wheel speed falls below the threshold (indicating potential lock), the system cross-checks with air speed data to confirm landing conditions and triggers deployment accordingly, improving reliability through multi-parameter verification.
2Reliability
If all ground spoilers are deployed simultaneously, then the lift reduction is maximized, but an excessive pitching moment loads the nose gear excessively
Solution Approach 1:
The system segments the ground spoiler deployment into sequential stages rather than simultaneous activation. Multiple ground spoilers are deployed at different time intervals, with later spoilers activated after a predetermined delay following the first spoiler deployment. This segmentation distributes the pitching moment over time, preventing excessive instantaneous load on the nose gear while maintaining effective lift reduction.
Data Source
AI summary
The present invention provides a drive system which can automatically deploy a ground spoiler even when a wheel is locked. A drive system for a ground spoiler deploys closed ground spoilers 4A to 4D when a wheel speed VW exceeds a wheel reference speed VW1 or when an air speed VB exceeds an air reference speed VB1 after a main gear 6 touches down. The system may also close the deployed ground spoilers 4A to 4D when the wheel speed VW is smaller than a wheel reference speed VW2 or when the air speed VB is smaller than an air reference speed VB2.