Tiltrotor Fixed Engine Rotor System with Rotating Pylon

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Solution Overview

Problem

Tilt rotor aircraft engines face challenges in operating in both vertical and horizontal orientations, limiting engine options and increasing certification, testing, and maintenance requirements due to the need for rotating engines, which complicates maintenance and inspection access.

Innovation Solution

A rotor system for tilt rotor aircraft with a fixed engine position on the wing, where the prop-rotor pylon is rotatable relative to the wing, allowing the aircraft to switch between helicopter and airplane modes, and a drive path mechanism aligns the axis of rotation with a gearbox for efficient torque transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the engine is mounted on the rotating nacelle to enable tilt rotor operation, then the aircraft can switch between helicopter and airplane modes, but the engine must operate in both vertical and horizontal orientations which limits engine options and increases certification and maintenance requirements

Engineering Contradiction:

Improvemode switching capabilityVSAvoidengine orientation requirements

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system is divided into three separate functional components: the fixed engine mounted on the wing, the rotatable nacelle containing the rotor hub, and the drive shaft connecting them. This segmentation allows the engine to remain stationary while the nacelle rotates, eliminating the need for the engine to operate in multiple orientations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of rotating the engine with the nacelle, the invention inverts the arrangement by keeping the engine fixed and rotating the nacelle independently. The drive shaft transmits power from the stationary engine to the rotating rotor hub, reversing the conventional approach where the engine would be mounted on the rotating component.

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If the engine rotates with the nacelle, then the thrust direction can be changed, but maintenance and inspection access around the engine is limited

Engineering Contradiction:

Improvethrust direction controlVSAvoidengine access

Core Design Contradiction:

Adaptability or versatilityVSEase of repair

Solution Approach 1:

By separating the engine from the rotating nacelle, the engine remains fixed on the wing structure, providing constant access for maintenance and inspection. The rotatable nacelle contains only the rotor hub and blades, which can rotate independently without affecting engine accessibility.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If a rotating engine arrangement is used, then tilt rotor functionality is achieved, but certification and testing requirements increase

Engineering Contradiction:

Improvetilt rotor operationVSAvoidcertification burden

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The invention inverts the conventional tilt rotor design by keeping the engine fixed and rotating the nacelle instead. This approach allows the engine to remain in a stationary, horizontally-oriented configuration that is easier to certify, while still achieving tilt rotor functionality through the rotation of the rotor hub and blades within the nacelle.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP2778063B1Tiltrotor aircraft with inboard wing mounted fixed engine arrangement

Publication Date: 2016.04.06 BELL HELICOPTER TEXTRON INC

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Figure 2B

AI summary

A rotor system (108, 109) for tilt rotor aircraft (100) comprises an engine (145) disposed at a first fixed position on a wing member (105), and a prop-rotor pylon (119) mechanically coupled to the engine (145) along a drive path extending through the wing member (105). The engine (145) is disposed adjacent a fuselage (103) of the tilt rotor aircraft (100), and the prop-rotor pylon (119) is configured to selectively rotate between a vertical position and a horizontal position. The prop-rotor pylon (119) is coupled to a plurality of rotor blades (110).