Martlet 4 Subsystem Testing

Below are tests we carried out (prior to the Coronavirus lockdown) of the subsystems that will be needed for our next rocket rocket project, the Martlet 4. Powered by our Pulsar hybrid rocket motor, Martlet 4 will be our largest rocket yet while its hybrid propsulsion provides some unique challenges.

Fill line disconnect system: ‘The Tower’

The oxidizer for our motor is nitrous oxide, which must be loaded onto the rocket’s tanks entirely by remote control for safety reasons. We thus need a mechanism to separate the high-pressure hose used to fill the tank prior to launch. Our disconnect system, nicknamed ‘The Tower’ involves an electric winch, a tower-mounted pulley and a quick disconnect. Well done to the team that put the tower together!

Drogue deployment test

Below is a test of the deployment of the drogue parachute. The drogue is the first parachute to deploy, which later pulls out the main parachute for landing. It is ejected by pressurizing the parachute bay with carbon dioxide. This test was carried out on the ‘Martlet 3C’ airframe, a prototype airframe of the same diameter of the eventual Martlet 4 rocket.

Other milestones included the test of the rocket’s main feed valve. This lightweight aluminium valve is driven by an electric motor and opens to a wide orifice to admit the oxidizer into the combustion chamber. It has so far been tested with a back-pressure of 70 bar.