Dual‑Deployment Rocket: Structural Tutorial

Motor Selection: Cesaroni 2372K1440

Due to accessibility of motors, the entire design of this rocket was based around the Cesaroni 2372K1440 solid rocket motor. Balancing the payload, motor and aerostructures together to achieve a desirable stability margin was the goal.

Motor Specs

• Total Impulse: 2372 N·s
• Average Thrust: 1440 N
• Max Thrust: ~1600 N
• Burn Time: ~1.65 s
• Diameter: 54 mm
• Length: 477 mm
• Propellant Mass: 1224 g
• Case Type: Cesaroni Pro54 6GXL

OpenRocket Simulation

Every rocket design begins with simulation software such as OpenRocket, RocketPy or MATLAB. Here, the team utilised OpenRocket to input each component’s weight, geometry and configuration. The important part here is maintaining a stability margin between 1.5–2.5, as per the Mach 2025 guidelines. Check the link for the full suite of requirements and competition standards: Mach 2025 Requirements PDF .

If you’re just getting started, OpenRocket is completely free, open-source, and well worth downloading — especially for hobbyist simulations, flight predictions, and early stability checks.

A complete openrocket design, ready for aerodynamic simulations.

OpenRocket Flight Data

These plots, generated by OpenRocket, offer insight into the rocket’s simulated flight performance — including altitude, velocity, acceleration, and aerodynamic drag throughout the ascent.

Full Rocket Assembly

Euan and Lewis holding Rocket the Bruce.

This page walks through the structural parts of a dual‑deployment rocket: from nose cone to fin can, plus payload bay and recovery system. Each section includes materials, dimensions, and assembly steps with image placeholders.

1 · Nose Cone

2 · Avionics Bay

• Material: Phenolic craft 2 mm wall
• Length: 200 mm
• Attachment: One bulkhead (wall division) is epoxied to the coupler and the other is epoxied to the eyebolts. The coupler is then epoxied to upper airframe (also phenolic craft)

The threaded screws act as a base to attach the electronics sled and are also acting as columns that will secure the avionics bay via nuts on the epoxied bulkhead.

Later, (airtight) holes are required in the bulkheads so that the flight computers can send the signal through the ignitors that activate the black powder charge, pressurising the airframe and pushing out the parachutes. This will be touched on later.

3 · Upper Airframe Tube

• Material Phenolic kraft, 141 mm OD, 3 mm wall
• Length: 500 mm
• Attachment: epoxy to avionics bay coupler

Arming switch holes are drilled on the upper airframe (this will be reflected upon in the conclusion, let's say it caused some issues). One for each flight computer, each computer can activate both main and drogue parachutes for redundancy.

4 · Payload: CanSat

5 · Lower Airframe Tube

The motor mount houses the motor according to its diameter. The centering rings allow the motor to be installed into an airframe thats larger, and safely transmit the thrust forces. The red motor retainer is then added to the bottom to keep the engine secured in every direction.

Once the vertical slots were machined (quite difficult with this brittle and large component), the assembly was inserted into the lower airframe where it was epoxied heavily to form one robust assembly.

7 · Recovery System & Test Videos

• Drogue: 14″ chute, BP release at apogee
• Main: 42″ chute, deployed at 300 m
• CanSat chute: 18″ chute, deployed at 300 m (had to be abandoned)
• Shock Cord: 1 m nylon, quick‑link anchors

Assembly: Connect cords to eyebolts on both separating assemblies, join the parachutes and pack with wadding to protect from ejection charge. We ended up moving the ejection charge from the underside of the avionics bay to the top of the motor. This was raised as an issue as there was a possibility that the ejection charge wouldnt push out the parachute but push it in.

Below are the final successful ejection tests from our recent visit at Mach 2025.