Airplane with Pivoting Rear Tail Unit for Flight Configuration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The standard configuration of an airplane with rear tail units results in inefficiencies during cruising flight, as the rear vertical tail contributes little to aerodynamics, adds weight and drag, and the rear horizontal tail degrades lift efficiency, while being underutilized and only beneficial during take-off and landing phases.
Innovation Solution
The airplane features a fuel transfer system and pivoting mechanism that allow the tail ends to pivot and adjust fuel distribution between two sets of fuel tanks, enabling the center of gravity to be shifted relative to the center of lift, and the tail ends to change positions from vertical to horizontal, optimizing the rear tail unit's functionality during different flight phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rear vertical tail and horizontal tail are maintained in a fixed standard configuration, then the airplane has stable aerodynamic characteristics during take-off and landing, but the rear tail unit adds weight and drag during cruising flight without contributing significantly to aerodynamics
Solution Approach 1:
The horizontal tail is made movable rather than fixed, allowing it to change configuration during flight. The tail can be pivoted to different positions (horizontal for cruising, vertical for take-off/landing) to optimize aerodynamic performance for each flight phase, eliminating the need to carry unnecessary tail surface area and weight throughout the entire flight
Solution Approach 2:
The aerodynamic parameters of the rear tail unit are changed by altering its orientation angle. By pivoting the tail between horizontal and vertical positions, the effective tail area and its aerodynamic contribution are dynamically adjusted to match the requirements of different flight phases, reducing drag and weight penalty during cruising
2Reliability
If the rear horizontal tail maintains a large surface area for stability, then the airplane has adequate pitch control during take-off and landing, but the rear horizontal tail degrades lift efficiency by approximately 5% during cruising flight
Solution Approach 1:
The horizontal tail surface area is dynamically adjusted by pivoting the tail structure. During take-off and landing, the tail is positioned horizontally with full surface area for maximum pitch control authority. During cruising flight, the tail is pivoted to a vertical position where it forms a vertical stabilizer, eliminating the parasitic drag and lift degradation associated with a large horizontal tail surface
Solution Approach 2:
The rear tail unit is designed to perform multiple functions by changing its orientation. In horizontal position, it provides pitch control and stability. When pivoted to vertical position, it serves as a vertical stabilizer for directional control. This multi-functionality allows the same structure to optimize aerodynamic efficiency for different flight phases without sacrificing stability
3Reliability
If the center of gravity is positioned forward for stability, then the airplane has inherent longitudinal stability, but the rear horizontal tail must exert a downward force that reduces overall lift and increases drag
Solution Approach 1:
The tail configuration is dynamically changed from horizontal to vertical position. When vertical, the tail ends act as a vertical stabilizer that provides directional stability without requiring the horizontal tail to generate downward force. This eliminates the lift degradation and associated drag that would result from maintaining a forward center of gravity with a fixed horizontal tail
4Reliability
If the rear vertical tail has a significant surface area for directional control, then the airplane has adequate yaw control during take-off and landing, but the rear vertical tail contributes little to aerodynamics during cruising flight and adds drag
Solution Approach 1:
The vertical tail surface is made dynamic by allowing the horizontal tail to pivot. When the horizontal tail is in vertical position, its tail ends form an effective vertical stabilizer for yaw control during take-off and landing. During cruising flight, the configuration is optimized to minimize drag while maintaining adequate directional control through the pivoted position
Data Source
AI summary
An airplane comprises a fuselage, two wings, engines, a rear tail unit comprising a horizontal tail provided with two tail ends, a first and a second set of fuel tanks, and a fuel transfer system configured to be able to transfer, at least in flight, fuel from one to the other of the first and second sets of fuel tanks, the tail ends being, in addition, mounted so as to be able to be pivoted, at least in flight, relative to the horizontal tail, the airplane thus having a configuration changeable in flight.