Basic rocket design

Learn the four component categories in OpenRocket and build a complete model rocket from scratch.

This section walks you through designing a basic rocket in OpenRocket. You will explore the available component categories, examine the A simple model rocket example design, and then build that same rocket from scratch.

This section assumes you have already installed OpenRocket and are familiar with the basic layout of the program.

Component configuration window

To start a new project, go to File > New. Save the design straight away with File > Save. You will be presented with a blank rocket design window.

In the top-right of the design window you will find the Add new component panel. It contains four categories:

Assembly Components

Components with no physical meaning of their own. Used to group components together (stages, boosters, pods).

Body Components and Fin Sets

Components that build the rocket’s external airframe — nose cones, body tubes, transitions, and fins.

Inner Components

Components placed inside the airframe — inner tubes, couplers, centering rings, bulkheads, and engine blocks.

Mass Components

Components that add mass or serve as recovery devices — parachutes, streamers, shock cords, and mass components.

Adding a body tube

Click the Body Tube icon in the Body Components and Fin Sets section. This opens the Body tube configuration window.

At the top of the window is the Component name field. The name you enter here appears in the design tree in the Rocket Design panel.

Below the name, several tabs are available:

General

Adjust the basic dimensions of the component using manual entry, spin boxes (coarse control), or sliders (fine control).

• The Automatic checkbox adjusts the component’s dimensions automatically based on the parent.
• The Filled checkbox sets the inner diameter to zero, creating a solid tube. Note how the component mass changes when this is checked.
• On the right side, Component material and Component finish drop-down menus let you select from a list of materials and finishes, each with its own weight and thickness.
• The Set for all button applies the selected finish to every component in the design.
• The live Component mass display at the bottom left updates automatically as you change parameter values.

Motor

Most parameters are grayed out unless you check the This component is a motor mount checkbox. Enabling this turns the body tube into a motor mount and unlocks motor configuration options.

Override

Manually override the mass and centre of gravity (CG) for this component. This is useful when you have weighed actual parts and want the simulation to reflect real-world measurements. See Overrides and surface finish for details.

Appearance

Customize the component’s look. The Figure style section affects the 2D schematic view. The Appearance section affects the 3D rendered view. You can load custom textures through the Texture drop-down menu.

Comment

Enter any notes about this component — why you chose specific values, construction notes, and so on.

The tabs available in the configuration window depend on the component type. For example, a nose cone has a Shoulder tab instead of a Motor tab.

After you close the Body Tube configuration window, all other component types in the panel become available. However, when building a rocket from scratch, you should always add a Nose cone first.

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Available design elements

Assembly components

Assembly components are not physical parts — they are attachment points on which the rocket’s framework is built. Each type acts as a container for physical parts and should never be left empty.

Component	Description
Stage	The basic framework element. Every rocket has at least one stage. Physical components attach to the stage.
Boosters	Attach only to a body tube. Can separate from the rocket during flight. Useful for modeling gliders or separate booster sections.
Pods	Attach only to a body tube. Cannot separate during flight. Used for side motors or adjacent airframe sections.

Body components and fin sets

These eight components make up the external airframe of the rocket.

Component	Description
Nose cone	The tip of the rocket. Usually the first component you add.
Body tube	The main cylindrical section of a stage.
Transition	Joins one body tube to another, usually of different diameter.
Trapezoidal fin	A fin set in a trapezoidal shape.
Elliptical fin	A fin set in an elliptical shape.
Freeform fin	A fin that can take any custom shape. Adding one opens a shape-editing window.
Tube fins	Fins made from body tube sections attached to the outside of the rocket.
Launch lug	Attaches to the outside of the body tube and guides the rocket along the launch rod.

Inner components

All inner components are placed inside the airframe.

Component	Description
Inner tube	Adds tubes inside the main body tube. Can be designated as a motor mount.
Coupler	Joins two airframe sections together in multi-stage rockets.
Centering ring	Supports internal components (such as a motor mount) at the center of a larger tube.
Bulkhead	A solid disc that forms a stop or barrier between two areas.
Engine block	Prevents the motor from moving forward in the motor mount tube.

Mass components

Component	Description
Parachute	Deploys to slow the rocket’s descent.
Streamer	Creates drag during descent on windier days when drift must be minimized.
Shock cord	Secures the nose cone to the body so it is not lost at ejection charge deployment.
Mass component	A general-purpose mass block used to adjust the rocket’s center of gravity. You can rename it to represent any physical item.

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CG and CP display

As you add and configure components, OpenRocket continuously updates and displays the Center of Gravity (CG) and Center of Pressure (CP) in real time in the rocket design window. The stability margin — the distance between CG and CP expressed in calibers (body tube diameters) — is shown as well.

Watch these indicators as you adjust component dimensions, materials, and positions. A rocket is stable when the CG is forward of the CP by at least 1.0 caliber for subsonic flights.

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Building A simple model rocket from scratch

The following steps recreate the A simple model rocket example design (File > Open example > A simple model rocket). Start with a new blank project.

1. Add the nose cone

   Click the Nose cone component in Body Components and Fin Sets.

   • Type: Ogive
   • Shape parameter: 1.0 (produces a tangent ogive)
   • Nose cone length: 10 cm
   • Base diameter: 2.5 cm
   • Wall thickness: 0.2 cm
   • Component material: Polystyrene
2. Configure the nose cone shoulder

   In the nose cone configuration window, switch to the Shoulder tab.

   • Diameter: 2.3 cm
   • Length: 2.0 cm
   • Thickness: 0.2 cm
   • Check the End capped box.
3. Set the nose cone appearance

   Switch to the Appearance tab. Leave the Figure style section unchanged.

   Under Appearance, change the colour to something lighter than black and adjust the Shine to 50%.

4. Add the body tube

   With the nose cone selected in the design tree, click the Body Tube component.

   • Length: 30.0 cm
   • Outer diameter: 2.5 cm
   • Inner diameter: 2.3 cm
   • Wall thickness: 0.1 cm
   • Leave Automatic and Filled unchecked.
   • Material: Cardboard
   • Finish: Regular paint
5. Add the fin set

   Select the body tube in the design tree, then click Trapezoidal in Body Components and Fin Sets.

   Leave the geometry settings as their defaults. On the right side:

   • Fin cross section: Rounded
   • Thickness: 0.2 cm

   Optionally customize the appearance.

6. Add the inner tube (motor mount)

   Select the body tube and click Inner tube.

   • Length: 7.5 cm
   • Plus (offset): 0.5 cm

   Switch to the Motor tab and check This component is a motor mount. Set Motor overhang to 0.3 cm. Click Close.

   Now click the Motors & Configuration tab in the main window. Click New Configuration, then left-click in the Inner Tube column and click Select motor.

   In the motor selection window:

   • Select Estes as the manufacturer.
   • Set the Total Impulse slider to A.
   • Check Limit motor diameter to mount diameter and Limit motor length to mount length.
   • Select the A8 motor and set the Ejection charge delay to 3. Click OK.

   Add the following motors as additional configurations (one New Configuration each):

   • Estes B6-4
   • Estes C6-3
   • Estes C6-5
   • Estes C6-7
7. Add the engine block

   Select the inner tube in the design tree, then click Engine block.

   • Inner diameter: 1.2 cm
   • Wall thickness: 0.3 cm
   • Position relative to: Top of the parent component
   • Plus: 0.2 cm
8. Add two centering rings

   Select the body tube. Click Centering ring to add the first one — leave all settings as defaults.

   Add a comment on the Comment tab: The centering ring automatically takes the outer diameter of the body tube and the inner diameter of the inner tube.

   Select the body tube again and add a second Centering ring.

   • Plus: -4.5 cm

   Add the same comment.

9. Add the shock cord

   Select the body tube and click Shock cord.

   • Plus: 2 cm
   • Packed length: 5.2 cm
   • Packed diameter: 1.2 cm

   Add a comment: The shock cord does not need to be attached to anything in particular, as it functions only as a mass component.

10. Add the parachute

    Select the body tube and click Parachute.

    • Plus: 3.2 cm
    • Packed length: 4.2 cm
    • Packed diameter: 1.8 cm
11. Add wadding (mass component)

    Select the body tube and click Mass component.

    • Mass: 2 g
    • Approximate density: 0.16 g/cm³
    • Length: 3.0 cm
    • Diameter: 2.3 cm
    • Plus: 8.0 cm
    • Name: Wadding
12. Add the launch lug

    Select the body tube and click Launch lug.

    • Length: 3.5 cm
    • Outer diameter: 0.7 cm
    • Inner diameter: 0.5 cm
    • Radial position: 19 degrees

You have now built a complete model rocket in OpenRocket. From here you can proceed to basic flight simulation or experiment with more advanced design techniques.