Adjustable Nose Landing Gear for Low-Speed Takeoff
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircrafts face challenges in taking off at lower speeds due to the sum of nose down thrust couple and aircraft inertial moment exceeding available aerodynamic control moments, and existing fixed length extensions for nose landing gear increase landing forces and stowage space requirements.
Innovation Solution
An adjustable nose landing gear system with a linkage member that operates to hike or de-hike the shock strut, automatically shortening it upon retraction, allowing for a variable pre-flight angle of attack and efficient stowage configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fixed length extension is incorporated into the nose landing gear system to increase pre-flight angle of attack, then takeoff speed is reduced, but landing forces increase and stowage space requirements increase
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed length extension with a telescopic landing gear system that can dynamically adjust its length. The landing gear extends to increase pre-flight angle of attack during takeoff, then retracts before landing to reduce landing forces, and can be stowed to minimize stowage space requirements. This dynamic adjustment resolves the contradiction by allowing the system to optimize for different operational phases.
2Speed
If a fixed length extension is incorporated into the nose landing gear system to increase pre-flight angle of attack, then takeoff speed is reduced, but stowage space requirements increase
Solution Approach 1:
The telescopic landing gear system dynamically adjusts its length based on operational requirements. During takeoff, it extends to increase angle of attack; during stowage, it retracts to minimize space requirements. This resolves the contradiction between needing extended length for low-speed takeoff and minimal length for compact stowage.
3Speed
If the shock strut is lengthened by pressurizing the piston-cylinder assembly to increase pre-flight angle of attack, then takeoff speed is reduced, but the shock strut requires additional actuation before retraction
Solution Approach 1:
The patent merges the hiking function with the retraction function by orienting the linkage member at an angle to the shock strut. As the landing gear retracts, the linkage member's geometry automatically causes the shock strut to shorten (de-hike). This combines two operations into one, reducing actuation complexity while maintaining the ability to achieve low-speed takeoff capability.
4Force
If a hikeable and de-hikeable nose landing gear system is used to address fixed extension drawbacks, then landing forces and stowage space are improved, but the system requires complex piston-cylinder assembly actuation
Solution Approach 1:
The patent combines the hiking and de-hiking functions with the retraction operation. The linkage member is oriented at an angle to the shock strut, creating a mechanical relationship where retraction automatically causes de-hiking. This merges multiple functions into a single operational sequence, reducing the need for separate actuation systems and simplifying the overall system while maintaining reduced landing forces.
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
Enables aircraft takeoff at lower speeds by adjusting the pre-flight angle of attack and optimizing stowage space, reducing landing forces and improving lift generation.
Implementation Method 1
A shock strut of the aforementioned hikeable and de-hikeable nose landing gear system may be lengthened or shortened by pressurizing the coaxially mounted piston-cylinder assembly
Implementation Method 2
a linkage member oriented with respect to a shock strut that operates to hike or de-hike the landing gear system while automatically shortening the shock strut, if necessary, upon retraction of the landing gear system into a stowage compartment of an aircraft
Data Source
AI summary
A landing gear system includes a shock strut assembly and a linkage member coupled to an aircraft. Preferably, the shock strut assembly and linkage member are oriented or angled relative to one another in a non-parallel relationship. Actuation of the linkage member moves the shock strut from a de-hiked to a hiked configuration or vice-versa. In addition, the orientation of the linkage member relative to the shock strut assembly permits it to automatically move the shock strut assembly to the de-hiked position during retraction of the landing gear system and prevents the shock strut assembly from exceeding a desired length during retraction. The linkage member may take the form of a hydraulic actuator having a lower end portion coupled to an inner cylinder of the shock strut assembly and an upper end portion coupled to the aircraft aft of where the shock strut assembly is coupled to the aircraft.