Junction Fairing Curvature for Aircraft Wave Drag Reduction
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Solution Overview
Problem
Subsonic airplanes experience increased drag due to shock waves forming on the convex and concave sides of their wings during transonic flight, leading to inefficient airflow and wave drag.
Innovation Solution
The airfoil-fuselage junction fairing is designed with a horizontal profile featuring a convex front segment, a concave intermediate segment, and a convex rear segment, along with specific geometric deviations and distances, to reduce shock wave formation and drag. This design minimizes aerodynamic interactions and optimizes airflow around the wing root.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the junction fairing outer surface is designed to minimize aerodynamic interactions with the airfoil (nearly straight convex profile), then the aerodynamic disruptions to the wing root are avoided, but shock waves form during transonic flight increasing wave drag
Solution Approach 1:
The invention applies curvature to the junction fairing horizontal profile by introducing a convex-concave-convex shape with specific radii of curvature. The first convex portion has a radius R1, the concave portion has a radius R2, and the second convex portion has a radius R3, where specific relationships between these radii create optimal flow conditions that reduce shock wave formation during transonic flight while maintaining smooth airflow at subsonic speeds.
2Ease of manufacture
If the junction fairing has a nearly straight convex horizontal profile, then the manufacturing is simplified, but the wave drag increases during transonic flight
Solution Approach 1:
The invention changes the geometric parameters of the junction fairing from a nearly straight profile to a profile with specific curvature radii (R1, R2, R3) and angular relationships. The concave portion angle α and the specific ratios between curvature radii create optimal aerodynamic characteristics that reduce wave drag during transonic flight, while the overall design remains manufacturable using conventional aircraft fabrication techniques.
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 optimized junction fairing reduces wave drag by up to 3% when combined with specific vertical profile modifications, enhancing aircraft performance by improving fuel efficiency and range.
Implementation Method 1
the airflow around the wings of these airplanes to enter a transonic state, creating shock waves on the convex side
Implementation Method 2
shock waves on the convex side, or even in some cases on the concave side, which increase the drag of the airplane by generating what is commonly called a wave drag
Data Source
AI summary
An aircraft portion includes a fuselage oriented in a longitudinal direction, an airfoil made up of at least one pair of wings arranged on either side of the fuselage in a transverse direction orthogonal to the longitudinal direction, and an airfoil-fuselage junction fairing at the interface between the airfoil and the fuselage. The junction fairing has, in a vertical plane, a lower profile and, in a horizontal plane, a horizontal profile at the junction of the outer surface of the junction fairing with the convex side of each wing. The horizontal profile and/or the lower profile successively has, in the longitudinal direction, a convex front segment, a concave intermediate segment, and a convex rear segment.