2018-19 HM-8P

Manufacturing

The Manufacturing team is in charge of building all of our necessary rocket components and providing them on time. Manufacturing largely occurs in the Cal Poly Machine Shops located in the hangar and Mustang 60. Much of the Propulsion system is machined from aluminum, but the team also gets to work with different materials like stainless steel and the aerospace grade ceramic, Macor. We train students in using simple hand tools all the way up to using the CNC machines because we believe in the importance of learning to design for manufacturability. By learning machining processes, CPSS club members can grow to better understand design, while also building rocket parts!

Propulsion

CPSS puts significant resources into the design and development of rocket motors. Our Propulsion Team handles the engineering, manufacturing, and testing of these motors. This year, we attempted to build a self pressurizing hybrid system. In previous years, we have used hydroxyl-terminated polybutadiene (HTPB) for solid fuel, nitrous oxide for a liquid oxidizer, and nitrogen gas as back pressure to push the nitrous oxide through our injector to burn the fuel.

To minimize complexity and reduce weight, we eliminated the nitrogen back pressure. Instead, we let the vaporized nitrous oxide push the liquid nitrous oxide into the fuel. However, even after successful flow tests, we ran into problems, burning through our fuel and melting our combustion chamber. From this, we reevaluated our options for building a hybrid rocket.

We decided to go back to our nitrogen pressurized system, and are working hard to manufacture and test everything before our launch date.

Mechanical Systems

The mechanical systems team is responsible for the recovery system and overall structure of the rocket. They work with computational fluid dynamics (CFD) to analyze the nose cone, boat tail, and tail fin designs, as well as the composite layup process.

Our recovery system is an integral part of a rocket, because in order to launch a rocket, we must also have a plan to safely recover it. Since our club works with high pressures, combustion, and dangerous levels of thrust, we implement safety every step of the way.

For our recovery system, we have a drogue chute deploy at apogee too keep the rocket from accelerating downward too quickly, and closer to the ground, the main chute is deployed for a safe landing.

Avionics

The Avionics team is responsible for flight control, telemetry and tracking our rocket as it flies, as well as the payload unit. They are responsible for ensuring that data is gathered and the system is reliable and safe. In CPSS, we design and assemble our own circuit boards entirely in-house to control our rockets.

We have redesigned our payload case to a stacked circuit board system, where each board has a different set of controls. This design is more space efficient for fitting in the rocket, and it a system is changed, only one circuit board needs to be remade without needing to manufacture an entire circuit board again.

Ground Support

The ground support team is responsible for preparing the rocket before flight or propulsion tests, acquiring data during testing operations and filling before launch, and communication between . They also build our test equipment to gather data during tests, such as pressure and thrust. The team works closely with the propulsion team to ensure that each system supports the other because in order to have a rocket with properly pressurized oxidizer tanks, the ground support team needs to successfully fill the tanks and disconnect the hoses leading to the rocket before launch.

This year, our ground support team has been working hard to upgrade our computer, HAL, to be even more reliable, be more organized, and have a better cooling system for our summer launches in the desert.

Last year, our rocket, Kronheim, didn’t launch because our fill tubes could not disconnect from the rocket after filling our tanks with nitrogen and nitrous oxide. Because approaching the rocket with high pressures would be extremely dangerous, we were unable to remove the tubes and unable to launch. This year, we designed and manufactured new “quick disconnects” that are much more reliable than the old ones.