Tail Cone Auxiliary Power Thrust Unit Drive System
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Solution Overview
Problem
Existing auxiliary power units (APUs) in aircraft are heavy and costly, and there is a need for a more efficient, reliable, and versatile power source that can provide power to hydraulic, electrical, and environmental systems on the ground and additional thrust during takeoff and climbing.
Innovation Solution
An auxiliary power and thrust unit (APTU) is integrated into the aircraft's tail cone, featuring a turbofan engine with a transmission assembly and drive shafts configured to optimize power transmission to auxiliary equipment while minimizing air flow obstruction, allowing for efficient operation in both power and thrust modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional auxiliary power unit (APU) is used to provide power to auxiliary systems, then the aircraft can operate hydraulic, electrical, and environmental systems on the ground, but the APU adds significant weight and cost to the aircraft
Solution Approach 1:
The patent applies multi-functionality by integrating a turbofan engine that can operate in multiple modes: providing auxiliary power to hydraulic, electrical, and environmental systems during ground operations, and generating thrust during takeoff and climbing phases. This eliminates the need for a dedicated single-function APU, reducing overall system weight while maintaining all required auxiliary power capabilities
Solution Approach 2:
The patent merges the auxiliary power function and thrust generation function into a single integrated turbofan engine system. By combining these previously separate functions into one unit, the design eliminates redundant systems and reduces total weight, while the engine can seamlessly transition between power-providing mode and thrust-providing mode
2Adaptability or versatility
If a turbofan engine is integrated into the tail cone with a transmission assembly and drive shafts, then the engine can power auxiliary equipment and provide thrust, but the drive shafts may obstruct air flow through the inlet duct
Solution Approach 1:
The patent positions the drive shafts in a transverse orientation perpendicular to the main inlet duct axis, and locates them outside the primary air flow path. This spatial arrangement in another dimension allows the drive shafts to transmit power effectively while minimizing interference with air flow through the inlet duct to the turbofan engine
Solution Approach 2:
The patent introduces a transmission assembly as an intermediary mechanism that efficiently transmits power from the turbofan engine to auxiliary equipment through drive shafts positioned to minimize air flow obstruction. The transmission assembly acts as a mediator that enables power transmission while maintaining optimal air flow paths
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 APTU provides efficient power to auxiliary systems on the ground and additional thrust during takeoff and climbing, improving performance, reliability, and space utilization within the aircraft, while reducing weight and cost compared to traditional APUs.
Implementation Method 1
a turbofan engine with a transmission assembly and drive shafts configured to optimize power transmission
Implementation Method 2
The engine includes a forward-facing main turbine shaft
Data Source
Figure 1
Figure 2
AI summary
An aircraft auxiliary power and thrust unit includes at least one blade mounted to a fan shaft which are mounted to a tail cone of the aircraft and rotatable relative to the tail cone. Also included is an air intake assembly which includes an opening defined by the tail cone and a channel in fluid communication with the opening and the at least one blade. A first drive shaft positioned to extend in a direction transverse to the fan shaft and engagageable to rotate with the fan shaft and first drive shaft engaged and the first drive shaft engagageable to a second drive shaft positioned transverse to the first drive shaft such that the second drive shaft rotates with the first drive shaft with the first and second drive shafts engaged. The second drive shaft is positioned outside of the channel of the air intake.