Wing Attachment

This section defines how wings are attached to the fuselage, including their position, orientation, and optional aerodynamic fairing.

Overview

A Wing Attachment combines the wing geometry with its placement in the airframe. It specifies where the wing root connects to the fuselage and how it is oriented.

Coordinate System

All attachment coordinates are relative to the SETUAV_BODY frame (origin at fuselage nose tip):

• X+: Aft (toward tail)
• Y+: Right (starboard)
• Z+: Up

Attachment Parameters

Position

Parameter	Unit	Description
position	object	Wing attachment position (required).
position.x	mm	Longitudinal position along fuselage (distance from nose tip).
position.y	mm	Lateral offset from centerline. Typically non-zero for V-tail or asymmetric configurations.
position.z	mm	Vertical offset from fuselage reference line. Positive values raise the wing.

Orientation

Parameter	Unit	Description
rotation	object	Wing attachment rotation (optional).
rotation.x	deg	Rotation around X-axis (longitudinal axis, roll). Used for dihedral angle or V-tail configurations. Positive rotation tilts the right wing upward (optional, default: 0).
rotation.y	deg	Rotation around Y-axis (lateral axis, pitch). Adjusts wing incidence angle (optional, default: 0).
rotation.z	deg	Rotation around Z-axis (vertical axis, yaw). Creates a global sweep effect for the entire wing (optional, default: 0).

Symmetry

Parameter	Type	Description
mirror	bool	If true, the wing is mirrored across the XZ-plane (Y=0) to create a symmetric pair. If false, only a single wing is placed.

Wing-Fuselage Fairing

A fairing is an aerodynamic transition surface that smoothly blends the wing root into the fuselage, reducing interference drag.

Fairing Parameters

Parameter	Type	Default	Description
scale	float	1.2	Uniform scaling factor for the fairing profile. Range: 1.1-1.4.
leading_curve	float	0.3	Leading edge curvature: positive = convex (curves outward), negative = concave (curves inward), 0 = linear. Range: -1.0 to 1.0.
trailing_curve	float	-0.2	Trailing edge curvature: positive = convex (curves outward), negative = concave (curves inward), 0 = linear. Range: -1.0 to 1.0.
continuity	str	G2	Surface continuity: G0 (positional), G1 (tangent), or G2 (curvature).

Fairing Geometry

The fairing is automatically generated by:

1. Extracting the wing root profile
2. Scaling it uniformly by the scale factor and positioning it to intersect the fuselage
3. Applying curvature control to create convex (outward) or concave (inward) transitions at leading and trailing edges
4. Lofting between profiles with specified continuity
5. Trimming the result against the fuselage surface

Curvature Control:

• Positive curve (0 to 1.0): Convex transition, curves outward - reduces interference drag
• Negative curve (-1.0 to 0): Concave transition, curves inward - creates smoother integration
• Zero curve: Linear transition

Typically, leading edges use slight positive curve (convex) while trailing edges use slight negative curve (concave) for optimal aerodynamics.

Example Configuration

wings:
  - tag: "main_wing"
    attachment:
      position:
        x: 450    # 450mm from nose
        y: 0      # Centerline
        z: 50     # 50mm above reference
      rotation:
        x: 2.0    # 2° dihedral
        y: 0      # No incidence offset
        z: 0      # No global sweep
      mirror: true       # Symmetric pair
      fairing:
        scale: 1.2
        leading_curve: 0.3
        trailing_curve: -0.2
        continuity: "G2"

    geometry:
      blending:
        ruled: false
        max_degree: 3
        continuity: "G2"
      profiles:
        - position:
            x: 0
            y: 0
            z: 0
          chord: 240
          rotation:
            y: 2.0
          airfoil: "naca2412"
        # Additional profiles...

  - tag: "horizontal_stabilizer"
    attachment:
      position:
        x: 1200   # Near tail
        y: 0
        z: 120
      rotation:
        x: 0
        y: 0
        z: 0
      mirror: true       # Symmetric pair
      fairing:
        scale: 1.15
        leading_curve: 0.2
        trailing_curve: -0.15
        continuity: "G1"

    geometry:
      blending:
        ruled: false
        max_degree: 3
        continuity: "G2"
      profiles:
        - position:
            x: 0
            y: 0
            z: 0
          chord: 150
          rotation:
            y: 0
          airfoil: "naca0012"
        # Additional profiles...