Helicopter Vertical Tail Concavity for Tail Rotor Anti-Torque
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Solution Overview
Problem
Existing helicopters require significant energy to generate anti-torque using the tail rotor due to interference between the main rotor's torque and the tail rotor's side wash, leading to inefficiencies and increased energy consumption.
Innovation Solution
A helicopter design featuring a vertical tail with a concave trailing edge and spoilers to minimize interference, combined with a tail rotor positioned to reduce side wash obstruction and enhance airflow management, along with structural modifications like strakes on the tail boom to improve anti-torque efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the vertical tail has a conventional straight trailing edge, then the structural simplicity is maintained, but the tail rotor energy consumption increases due to side wash obstruction
Solution Approach 1:
The trailing edge of the vertical tail is divided into multiple sections with different geometries. The concave portion creates distinct airflow zones that separate the tail rotor downwash from the vertical tail surface, reducing interference while maintaining structural integrity through modular construction
Solution Approach 2:
The trailing edge geometry is modified by introducing a concave dimension that creates depth variation. This dimensional change allows the tail rotor downwash to flow through the concave region without obstructing the vertical tail, effectively utilizing three-dimensional space to resolve the two-dimensional conflict between tail surface area and rotor clearance
2Productivity
If the trailing edge is made concave to reduce interference, then the anti-torque efficiency is improved, but the structural strength may be compromised
Solution Approach 1:
The concave geometry is applied locally to specific portions of the trailing edge rather than the entire structure. This localized modification optimizes airflow separation in critical regions while preserving the structural strength of the overall vertical tail assembly through selective geometric adjustment
3Stability of the object's composition
If spoilers are added to suppress vortices, then the airflow stability is improved, but the device complexity increases
Solution Approach 1:
Spoilers are introduced as intermediary elements that actively manage vortex formation and airflow separation. These components mediate between the concave trailing edge geometry and the incoming airflow, stabilizing the flow pattern and reducing turbulent interactions without requiring fundamental redesign of the primary vertical tail structure
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 design reduces the energy required to rotate the tail rotor, enhances stability, and improves hovering and lateral movement performance by optimizing anti-torque generation, thereby reducing operational energy consumption and maintaining structural integrity.
Implementation Method 1
the rotation of the main rotor generates torque in the direction opposite to the rotational direction of the main rotor
Implementation Method 2
a tail rotor, which generates anti-torque to cancel torque generated by rotation of the main rotor
Implementation Method 3
The spoilers suppress generation of vortices around the concave trailing edge by separating airflow on left and right surfaces of the vertical tail respectively
Implementation Method 4
The spoilers suppress generation of vortices around the concave trailing edge
Implementation Method 5
occluding an opening, formed on the trailing edge side of the vertical tail after cutting out the part, by attaching a cover made of a flat plate to the opening
Data Source
AI summary
A vertical tail of a helicopter has a leading edge and a trailing edge concave toward the leading edge. The helicopter includes a main rotor and a tail rotor for generating anti-torque to cancel torque generated by rotation of the main rotor. The trailing edge is concave within a range within which the vertical tail overlaps a circular region, formed as a rotation range of the tail rotor, in a rotation axis direction of the tail rotor.