Tiltrotor Outboard Engine Drive System With Offset Spindle
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Solution Overview
Problem
Existing tiltrotor aircraft drive systems face challenges in optimizing engine placement and pylon rotation for efficient flight modes, leading to complexity and weight issues, as well as limited structural support and clearance.
Innovation Solution
A drive system design where a fixed engine is located outboard of the rotating rotor pylon, with a spiral bevel gear transitioning power from the engine to the proprotor gearbox, allowing for reduced complexity and weight, and enabling the spindle to be positioned within the wing torque box for increased structural efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the engine is positioned at a fixed location on the wing member and the proprotor pylon is rotatably mounted on a spindle, then the tiltrotor aircraft can transition between helicopter and airplane modes, but the drive system complexity and weight increase
Solution Approach 1:
The drive system is segmented into distinct functional components: a fixed engine positioned at a first location, a rotatable proprotor pylon with its own rotational axis, and a gearbox with a separate rotational axis. This segmentation allows each component to be optimized independently while reducing overall system complexity through modular architecture.
Solution Approach 2:
The invention introduces a second rotational dimension by allowing the proprotor pylon to rotate about a rotational axis that is distinct from the spindle's rotational axis. This dimensional change enables flexible power transmission paths and accommodates both helicopter and airplane flight modes without requiring a single complex universal mechanism.
2Adaptability or versatility
If the engine is positioned at a fixed location on the wing member and the proprotor pylon is rotatably mounted on a spindle, then the tiltrotor aircraft can transition between helicopter and airplane modes, but the system weight increases
Solution Approach 1:
By segmenting the drive system into a fixed engine, a rotatable pylon, and a separate gearbox, each component can be minimized in weight for its specific function. The engine remains fixed and lightweight, the pylon is optimized for rotation, and the gearbox is positioned independently, collectively reducing total drive system weight compared to a fully integrated design.
Solution Approach 2:
The second rotational axis of the pylon creates additional spatial dimensions for power transmission, allowing more efficient routing of drive shafts and reducing the need for heavy structural support elements. This dimensional flexibility enables weight reduction in the overall drive system architecture.
3Device complexity
If the proprotor pylon is rotatably mounted on a spindle with aligned rotational axes, then the power transmission is simplified, but the structural support and clearance are limited
Solution Approach 1:
The proprotor pylon is given a second rotational axis that is distinct from the spindle's axis, creating additional spatial dimensions. This allows the power transmission path to be routed through three-dimensional space rather than being constrained to a single plane, providing better structural support distribution and improved clearance between components.
Solution Approach 2:
The gearbox is positioned at a location with its own rotational axis that is optimized for local structural support conditions and clearance requirements. This localized optimization allows the power transmission system to adapt to varying structural constraints at different positions in the aircraft, improving both strength and clearance locally while maintaining overall system simplicity.
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
This configuration simplifies the drive system, reduces weight, and enhances structural support, allowing for flexible rotor alignment and improved flight mode transitions between helicopter and airplane modes.
Implementation Method 1
a spiral bevel gear transitioning power from the engine to the proprotor gearbox
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
The present invention includes a rotorcraft drive system (200), method, and aircraft (100) comprising a fixed engine; a rotating spindle (210) that rotates a proprotor gearbox (214) and rotor pylon between a hover and forward flight position, wherein the rotating spindle (210) rotates about a rotation bearings on two inboard ribs of a wing member (105); and an interconnect drive shaft (216) connected to the fixed engine, wherein the interconnect drive shaft (216) passes through an aft cove of the wing member (105) and connects to the engine via a forward-aft drive shaft (236), wherein the forward-aft drive shaft (236) is connected to the proprotor gearbox (214) to provide power to a proprotor.