Launch Lug Dialog

The Edit Launch Lug Dialog in SpaceCAD 7 allows users to configure launch lugs, which are small, external elements attached to the body of the rocket. Launch lugs help guide the rocket along the launch rod during the early stages of flight, ensuring a stable and controlled ascent until the rocket gains enough speed to fly on its own. This dialog allows users to set the material, dimensions, and positioning of the launch lug.

Key Fields and Features:

1. Launch Lug Name

• Editable field to specify the name of the launch lug.
• Example: “Launch Lug” or “Guide Lug.”

2. 2D Color

• Allows users to assign a custom color to the launch lug for easy identification in the design view.
• Example: The launch lug is assigned a Custom Purple color.

3. Load from Database

• Users can load pre-configured launch lugs from the SpaceCAD database, simplifying setup by using standard industry parts.

Material and Structural Properties:

4. Material

• Defines the material used for the launch lug, such as paper, plastic, or metal.
• Change Button: Opens the material selection dialog, allowing users to select a material based on the design’s structural needs.
• Example: Paper is lightweight, while plastic or metal is more durable for high-powered rockets.

5. Fix Weight and Fixed CG

• Fix Weight at: Users can manually set a fixed weight for the launch lug, overriding the calculated weight.
• Fixed CG Position at: Allows users to manually set the center of gravity (CG) for the launch lug, which can influence the rocket’s overall balance.

6. Length

• Defines the length of the launch lug, which affects how much of the rocket is guided during the initial launch phase.
• Example: A 50.8 mm long launch lug provides a good balance between guidance and weight for most rocket designs.

7. Diameter

• Specifies the internal diameter of the launch lug, which must match the diameter of the launch rod for a secure fit.
• Example: A 4.4 mm diameter fits standard launch rods used in model rocketry.

8. Wall Thickness

• Defines the thickness of the launch lug’s walls, which impacts the overall strength and weight of the element.
• Example: The wall thickness can vary based on the material used, but 0.0 mm indicates a default value or a simplified model.

Positioning and Alignment:

9. Start Angle (°)

• Specifies the angle at which the launch lug is attached to the rocket, typically along the longitudinal axis.
• Example: A 0-degree angle indicates that the lug is aligned along the rocket’s vertical centerline, but users can adjust this angle for specialized designs.

Internal Element Positioning

The launch lug, like other external elements, can be positioned relative to the rocket’s structure in four ways:

• Absolute Position: Sets the exact distance from a reference point and keeps the position fixed.
• Relative to Top of Owner: Adjusts the position relative to the top of the rocket element (e.g., body tube) that houses the launch lug.
• Relative to Middle of Owner: Positions the launch lug relative to the middle of the owning element.
• Relative to Back of Owner: Keeps the launch lug positioned relative to the back of the owning element, ensuring that it stays correctly aligned during design adjustments.

10. Distance from Owner’s Top

• Specifies the distance between the top of the owning element and the launch lug, ensuring precise placement.
• Example: The launch lug is positioned 111.1 mm from the top of the body tube.

Additional Controls:

11. Preview Button

• Provides a real-time preview of the launch lug and its placement on the rocket design. This feature allows users to visually inspect the lug’s position before saving the changes.

12. OK and Cancel Buttons

• OK: Saves the configuration and applies the launch lug to the rocket.
• Cancel: Closes the dialog without saving changes.

Example Workflow:

1. Configuring a Launch Lug for a Standard Rocket:

   • Open the Edit Launch Lug Dialog and set the name to “Launch Lug.”
   • Choose Paper as the material for a lightweight design.
   • Set the length to 50.8 mm for standard guidance and the diameter to 4.4 mm to fit a common launch rod.
   • Position the launch lug 111.1 mm from the top of the body tube and ensure it is aligned at a 0-degree angle.
   • Click Preview to check the placement and OK to apply the launch lug.

2. Designing a Launch Lug for a High-Power Rocket:

   • Open the Edit Launch Lug Dialog and choose Plastic or Metal as the material for durability.
   • Increase the length and diameter to accommodate a larger rocket and ensure it fits a thicker launch rod.
   • Adjust the start angle if necessary for specialized launch pad designs.
   • Preview the design to ensure proper placement before saving with OK.