Tail Cone Auxiliary Jet Engine Mounting Structure
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Solution Overview
Problem
Commercial aircraft typically have multiple engines of the same model for maintenance simplicity but lack optimal thrust balance, mass distribution, and aerodynamic efficiency, and they carry a heavy auxiliary power generator (APU) for energy and propulsion, which is inefficient and noisy.
Innovation Solution
An auxiliary propulsive system with a jet engine integrated into the aircraft's fuselage tail cone, featuring a carrying structure with overhanging beams and frames for secure mounting and air supply, allowing for optimal operation without aerodynamic penalties and reducing the need for a separate APU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If multiple engines of the same model are used, then maintenance simplicity is improved, but thrust balance and aerodynamic efficiency deteriorate
Solution Approach 1:
The propulsion system is segmented into different engine types: primary engines for main propulsion and a secondary engine for auxiliary functions. This allows each engine type to be optimized for its specific function while maintaining operational flexibility through the secondary engine that can be activated only when needed.
Solution Approach 2:
The secondary engine is designed with multi-functionality, serving both as an auxiliary power unit for energy generation and as a supplemental propulsion engine. This universal design eliminates the need for separate dedicated systems, improving overall system efficiency while maintaining maintenance simplicity through standardized engine types.
2Adaptability or versatility
If an auxiliary power generator (APU) is installed, then autonomous energy generation is improved, but mass and noise increase
Solution Approach 1:
The auxiliary power generation function is merged with the propulsion system by using the same secondary jet engine for both purposes. This consolidation eliminates the need for a separate APU, reducing mass while maintaining autonomous energy generation capability when needed.
Solution Approach 2:
The secondary engine serves dual functions as both an auxiliary power generator and a propulsion engine, replacing the need for dedicated separate systems. This multi-functionality reduces overall system mass while maintaining adaptability for energy generation requirements.
3Adaptability or versatility
If an auxiliary power generator (APU) is installed, then autonomous energy generation is improved, but noise levels increase
Solution Approach 1:
The auxiliary power generation function is merged with the propulsion system, using the same secondary jet engine for both purposes. This eliminates the need for a separate APU that would generate additional noise, thereby reducing overall noise levels while maintaining energy generation capability.
Solution Approach 2:
The secondary engine serves dual functions as both an auxiliary power generator and a propulsion engine, replacing the need for dedicated separate systems. This multi-functionality reduces overall system noise while maintaining adaptability for energy generation requirements.
4Adaptability or versatility
If a secondary engine is added for APU functions, then energy generation capability is improved, but device complexity increases
Solution Approach 1:
The auxiliary power generation function is merged with the propulsion system by using the same secondary jet engine for both purposes. This consolidation reduces device complexity by eliminating the need for separate APU systems, their dedicated air intakes, and associated infrastructure.
Solution Approach 2:
The secondary engine serves dual functions as both an auxiliary power generator and a propulsion engine, reducing the number of separate components needed. This multi-functionality simplifies the overall system architecture while maintaining energy generation capability.
5Productivity
If the secondary engine is positioned in the fuselage tail section, then aerodynamic integration is improved, but mechanical installation complexity increases
Solution Approach 1:
The installation structure is segmented into modular components including beams, frames, and half-frames that can be assembled independently. This modular approach simplifies mechanical installation while maintaining the desired aerodynamic integration of the secondary engine in the fuselage tail section.
Solution Approach 2:
The secondary engine is positioned in the fuselage tail section, utilizing the longitudinal dimension of the aircraft structure. This positioning optimizes aerodynamic integration by aligning the engine with the aircraft's centerline, while the modular structural components facilitate ease of installation through standardized attachment points.
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 optimizes the size and efficiency of main engines, reduces noise, and minimizes the mass of main engines by providing additional thrust only when needed, enhancing fuel efficiency and reducing noise levels during flight.
Implementation Method 1
an auxiliary engine, a carrying structure to which is fixed the auxiliary jet engine
Implementation Method 2
auxiliary jet engine... generates a thrust directed backwards of the aircraft
Data Source
AI summary
A propulsive system for an aircraft including an auxiliary jet engine is integrated into a tail cone of a fuselage. A carrying structure of the jet engine is primarily formed with beams and frames or half-frames to which the auxiliary jet engine is fixed by lateral beams. The beams are interdependent of the frames and half-frames, and the beams are overhanging behind a frame behind which is fixed the engine. Each beam includes a lower half-beam and a higher half-beam, separated on at least a part of its length ahead from attachments of the jet engine to determine a space free of structure impediment for lateral air intakes.