Fixed Engine Tiltrotor Pylon with Rotating Drive Shaft
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Solution Overview
Problem
Tilt rotor aircrafts face challenges with engine operation in vertical 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 with a fixed engine nacelle and a rotatable prop-rotor pylon, where the engine is coupled to the rotor hub through gears, and an independent interconnect drive shaft provides power to the rotor hub, allowing the aircraft to switch between helicopter and airplane modes while maintaining engine stability and accessibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the engine is mounted to rotate with the rotor hub, then the tilt rotor aircraft can switch between helicopter and airplane modes, but the engine must be capable of operating in vertical orientation which limits engine options and increases certification, testing, and maintenance requirements
Solution Approach 1:
The system is divided into three main segments: the fixed engine nacelle, the rotatable prop-rotor pylon, and the rotor hub. This segmentation allows the engine to remain stationary while the pylon and rotor assembly rotate independently, resolving the contradiction by separating the engine from the rotating components.
Solution Approach 2:
The prop-rotor pylon acts as an intermediary between the fixed engine and the rotor hub. It transmits power from the stationary engine to the rotating rotor while accommodating the rotation, thus enabling mode switching without requiring the engine itself to rotate or operate in vertical orientation.
2Adaptability or versatility
If the engine rotates along with the rotor hub, then the aircraft can transition between modes, but maintenance and inspection access around the engine is limited
Solution Approach 1:
By separating the engine into a fixed nacelle from the rotating pylon-rotor assembly, the engine remains stationary and accessible for maintenance and inspection, while the other components handle the rotation required for mode transitions.
Solution Approach 2:
The engine is extracted from the rotating assembly and placed in a fixed position, removing it from the rotational motion. This extraction allows maintenance personnel to access the engine without dealing with rotating parts or complex safety procedures associated with rotating engines.
3Ease of repair
If the engine is fixed while the pylon rotates, then maintenance access is improved, but a mechanism is needed to transmit power from the stationary engine to the rotating rotor hub
Solution Approach 1:
The prop-rotor pylon serves as a mechanical intermediary that receives power from the stationary engine through a drive shaft and transmits it to the rotating rotor hub. This intermediary mechanism allows power transmission across the interface between stationary and rotating components without requiring the engine to rotate.
Solution Approach 2:
The power transmission system incorporates dynamic elements that accommodate the rotation of the pylon while maintaining continuous power flow from the stationary engine to the rotating rotor. The system adapts to the changing orientation during mode transitions while maintaining functional connectivity.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A rotor system (108) for tilt rotor aircraft (100) comprises an engine (145) disposed at a first fixed location on a wing member (105); a prop-rotor pylon (119) mechanically coupled to the engine (145) along a drive path, and a gearbox (161) disposed in the drive path. The prop-rotor pylon (119) is rotatably mounted on a spindle (155), and the prop-rotor pylon (119) is configured to selectively rotate about a rotational axis of the spindle (155) between a vertical position (8 Fig 3A, 3B, 4B) and a horizontal position (Fig 2A, 2B, 4A). The gearbox (161) comprises a rotational axis aligned with the rotational axis of the spindle (155).