Articulated Horizontal Tail Units for Drag Reduction
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Solution Overview
Problem
Conventional aircraft with vertical tail units incur significant drag and weight, with limited usefulness during flight phases, particularly during cruising.
Innovation Solution
The aircraft features a tail unit system with port and starboard horizontal tail units articulated on two different axes of rotation, eliminating the need for a vertical tail unit by using a structural element housed inside the fuselage, actuation systems for rotational displacement, and pivot links with double end fittings, allowing for reduced drag and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vertical tail unit is used for yaw control, then stability during take-off and landing is improved, but drag and weight increase significantly
Solution Approach 1:
The patent extracts the yaw control function from the conventional vertical tail unit and relocates it to horizontal tail units that can articulate about a longitudinal axis. This allows the vertical tail unit to be removed entirely, eliminating its weight and drag penalties while preserving yaw control capability through the modified horizontal tail units.
Solution Approach 2:
The horizontal tail units are designed with dual functionality: they provide pitch control through articulation about the lateral axis and yaw control through articulation about the longitudinal axis. This multi-functionality eliminates the need for separate vertical and horizontal tail units, reducing overall weight and drag while maintaining stability during all flight phases.
2Reliability
If a vertical tail unit is used for stability, then yaw control is improved, but aerodynamic drag increases
Solution Approach 1:
The patent extracts the yaw control function from the vertical tail unit and transfers it to the horizontal tail units. By removing the vertical tail unit, the source of significant aerodynamic drag is eliminated, while yaw control is maintained through the articulated horizontal tail units that can move about the longitudinal axis.
Solution Approach 2:
The horizontal tail units are designed with dynamic articulation capabilities about both the lateral and longitudinal axes. This dynamic configuration allows the tail units to adapt their orientation and control surface deflection to provide effective yaw control while minimizing drag, unlike the fixed vertical tail unit that creates continuous drag regardless of flight phase.
3Adaptability or versatility
If conventional vertical and horizontal tail units are used, then all flight phases are covered, but device complexity increases
Solution Approach 1:
The patent designs the horizontal tail units to perform multiple functions: pitch control through lateral axis articulation and yaw control through longitudinal axis articulation. This multi-functionality consolidates the roles of separate vertical and horizontal tail units into a single integrated system, reducing overall device complexity while maintaining adaptability across all flight phases.
Solution Approach 2:
The patent merges the functions of the vertical tail unit and horizontal tail unit into a single integrated horizontal tail unit system with dual-axis articulation. By combining these previously separate systems, the patent reduces the number of components, simplifies the tail unit structure, and eliminates the need for complex interactions between separate vertical and horizontal tail systems.
Data Source
AI summary
An aircraft comprising a fixed structure, a fuselage mounted on the fixed structure and a tail unit system comprising a structural element housed inside the fuselage and mounted to be rotationally mobile relative to the fixed structure about a transverse axis of rotation parallel to a transverse axis of the aircraft. A first actuation system displaces the structural element in rotation about the transverse axis of rotation, on either side of the structural element. A horizontal tail unit has one end rotationally mobiley mounted on the structural element about a longitudinal axis of rotation parallel to a longitudinal axis of the aircraft and another end which extends out of the fuselage by passing through a window in the fuselage. For each horizontal tail unit, a second actuation system displaces the horizontal tail unit in rotation about the longitudinal axis of rotation.