Purpose

The purpose of this paper is to present a novel retractable main landing gear for a light amphibious airplane, while the design, synthesis and analysis are given in details for constructing the main landing gear.

Design/methodology/approach

The constraint three-position synthesis has given the correct path of all linkages that suitably fit the landing gear into the compartment. The additional lock-link is introduced into the design to ensure the securement of the mechanism while landing. Having the telescopic gas-oil shock strut as a core element to absorb the impact load, it enhances the ability and efficiency to withstand higher impact than others type of light amphibious airplane.

Findings

By kinematics bifurcation analysis, the optimized value of the unlock spring stiffness at 90 N/m can be found to tremendously reduce the extended-retracted linear actuator force from 500 N to 150 N at the beginning of the retraction sequence. This could limit the size and weight of the landing gear actuator of the light amphibious airplane.

Practical implications

The drop test of the landing gear to comply with the ASTM f-2245 (Standard Specification for Design and Performance of a Light Sport Airplane) reveals that the novel landing gear can withstand the impact load at the drop height determined by the standard. The maximum impact loading 4.8 G occurs at the drop height of 300 mm, and there is no sign of any detrimental or failure of the landing gear or the structure of the light amphibious airplane. The impact settling time response reaches the 2% of steady-state value in approximately 1.2 s that ensure the safety and stability of the amphibious airplane if it subjects to an accidentally hard landing.

Originality/value

This paper presents unique applications of a retractable main landing gear of a light amphibious airplane. The proposed landing gear functions properly and complies with the drop test standard, ensuring the safety and reliability of the airplane and exploiting the airworthiness certification process.

中文翻译：

---

轻型两栖飞机新型收放起落架设计、综合、分析与实现

目的

本文的目的是提出一种新型的轻型水陆两栖飞机可收放式主起落架，并对主起落架的构造进行了详细的设计、综合和分析。

设计/方法/方法

约束三位置综合给出了适合将起落架安装到隔间中的所有连杆的正确路径。设计中引入了额外的锁定连杆，以确保着陆时机构的安全。以伸缩式油气减震支柱作为吸收冲击载荷的核心元件，相比其他轻型水陆飞机，其承受更高冲击的能力和效率得到了提高。

发现

通过运动学分岔分析，可以发现解锁弹簧刚度在 90 N/m 时的优化值可在缩回序列开始时将伸展-缩回线性致动器力从 500 N 大幅降低至 150 N。这可能会限制轻型水陆两用飞机起落架致动器的尺寸和重量。

实际影响

符合 ASTM f-2245（轻型运动飞机设计和性能标准规范）的起落架跌落测试表明，新型起落架可以承受标准确定的跌落高度下的冲击载荷。最大冲击载荷4.8 G发生在300毫米的坠落高度，起落架或轻型两栖飞机的结构没有任何损坏或失效的迹象。冲击稳定时间响应在约1.2 s内达到稳态值的2%，保证了水陆两栖飞机意外硬着陆时的安全性和稳定性。

原创性/价值

本文介绍了轻型水陆两用飞机可伸缩主起落架的独特应用。拟议的起落架功能正常并符合跌落测试标准，确保飞机的安全性和可靠性，并利用适航认证程序。