Rotorcraft Non-Retractable Wheel-Type Landing Gear With Load Distribution

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Solution Overview

Problem

Conventional retractable wheel-type landing gears for rotorcraft increase design complexity, weight, and require significant storage volume, while non-retractable gears lack efficient load distribution and maintenance accessibility.

Innovation Solution

A non-retractable wheel-type landing gear design with a shock absorber attached to the fuselage through multiple fixations and a drag link, allowing for compact integration and improved load distribution, with simplified attachment points for easy maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a retractable wheel-type landing gear is used, then aerodynamic drag is reduced and flight speed is improved, but design complexity and weight increase

Engineering Contradiction:
Improveflight speedVSAvoidlanding gear complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The landing gear is divided into modular components: shock absorber assembly, wheel assembly, brake assembly, and attachment fittings. Each component can be independently designed, manufactured, and maintained. The shock absorber is separated into tube and rod components with distinct functions, allowing optimized design of each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of retracting the landing gear to reduce drag, the patent accepts the drag penalty and uses the saved complexity for other improvements. The inverted approach fixes the landing gear in place, eliminating retraction mechanisms while maintaining adequate aerodynamic performance through proper positioning and sizing.

Inventive Principle:
Principle #13The other way round (Inversion)

2Object-generated harmful factors

If a retractable landing gear is used, then aerodynamic drag is reduced, but storage volume requirements increase

Engineering Contradiction:
Improveaerodynamic dragVSAvoidstorage volume
Core Design Contradiction:
Object-generated harmful factorsVSVolume of stationary object

Solution Approach 1:

The landing gear is extracted from the fuselage interior and positioned in external or semi-external mounting locations. This eliminates the need for internal storage compartments and allows the gear to be permanently positioned in optimized locations without compromising fuselage volume for payload or cargo.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If a non-retractable landing gear is used, then design simplicity and weight are improved, but maintenance accessibility is poor

Engineering Contradiction:
Improvelanding gear simplicityVSAvoidmaintenance accessibility
Core Design Contradiction:
Device complexityVSEase of repair

Solution Approach 1:

The landing gear is divided into modular components: shock absorber assembly, wheel assembly, brake assembly, and attachment fittings. Each component can be independently designed, manufactured, and maintained. The shock absorber is separated into tube and rod components with distinct functions, allowing optimized design of each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Serviceable fittings and attachment points are provided as intermediary interfaces between the landing gear components and the rotorcraft fuselage. These fittings allow for easy connection and disconnection of the landing gear from the fuselage, facilitating maintenance and replacement without requiring complex disassembly procedures.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Weight of stationary object

If a non-retractable landing gear is used, then weight is reduced, but interface loads increase

Engineering Contradiction:
Improvelanding gear weightVSAvoidinterface loads
Core Design Contradiction:
Weight of stationary objectVSForce

Solution Approach 1:

The landing gear is divided into modular components: shock absorber assembly, wheel assembly, brake assembly, and attachment fittings. Each component can be independently designed, manufactured, and maintained. The shock absorber is separated into tube and rod components with distinct functions, allowing optimized design of each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The attachment fittings are designed with localized reinforcement and optimized geometry to distribute interface loads effectively. The shock absorber mountings are positioned and dimensioned to optimize the distribution of reaction forces to the fuselage structure, with local strengthening at critical attachment points.

Inventive Principle:
Principle #3Local quality

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

The design minimizes housing volume, reduces interface loads, and enhances maintenance accessibility, providing improved weight efficiency and stability without elastic behavior, suitable for rotorcraft with tricycle-type layouts.

Implementation Method 1

a shock absorber with a length axis and a circumferential direction, the shock absorber being connected to the at least one wheel and including a shock absorber tube with a length direction, which comprises in the length direction an open end and an axially opposed closed end; and a shock absorber rod telescopically mounted to the shock absorber tube via the open end

Methodology Applied
Scientific EffectShock absorption: Damping

Data Source

PatentEP4389598B1A rotorcraft with a non-retractable wheel-type landing gear
Publication Date: 2025.10.22 AIRBUS HELICOPTERS DEUT GMBH
  • EP4389598B1 patent drawingFigure 1
  • EP4389598B1 patent drawingFigure 2
  • EP4389598B1 patent drawingFigure 3

AI summary

A rotorcraft comprising a fuselage (2) forming at least one lower lateral fuselage compartment (2c) with at least a first fitting (10a), a second fitting (11c), and a third fitting (11d); and at least one non-retractable wheel-type landing gear (8) that comprises: at least one wheel (8a); a shock absorber (8b) with a shock absorber tube (8c) having an open end (8g) and an axially opposed closed end (8f), and a shock absorber rod (8d) telescopically mounted to the shock absorber tube via the open end; a first fixation (8p) provided close to the open end on the shock absorber tube and connected to the first fitting; a second fixation (8e) provided close to the closed end on the shock absorber tube and connected to the second fitting; and a third fixation (8i) provided close to the closed end on the shock absorber tube and connected to the third fitting.