Testing Campaign
Motor Characterization
Motor Characterization tests are a small scale test of our engine's operation. We assemble 1/6th scale fuel grains in an overbuilt wall mounted test stand. We then conduct a fill operation with Nitrous-Oxide the pressurize with nitrogen to act as an Ullage Gas. We then inject pure oxygen into the combustion chamber, then quickly ignite a steel wool burn wire to pyrolyse the fuel grain. Then, the main valve is opened, dumping liquid Nitrous-Oxide on the combustion chamber creating thrust. This simulates engine operation and collects data on thrust and pressure in the oxidizer tank as it fills and fires. This test is essential for characterizing the fuel combustion inside the engine. We need to collect data to determine the fuel regression coefficients, which are essential values for the performance model that can only be determined experimentally.
Hydrostatic Testing
Hydrostatic tests involve filling the combustion chamber with water, then pressurizing to 1.5X the expected operating pressure of 1000 psi. This test examines the sealing ability of the engine under high pressures. This test is essential to verify the the manufacturing and assembly was done correct, ensuring that all components are rated to above the expected operating conditions. This test utilizes water to hold pressure because of water's incompressible quality. This ensures that if a structural failure of the chamber walls were to occur, no one conducting the test would get hurt by the aftermath.
Cold Flow
A cold flow test is a simulation of engine operation, without the use of any heat or combustion processes. Practically, this involves the oxidizer tank being filled and pressurized, then injected into an empty combustion chamber. Data is collected on the oxidizer tank weight and pressure, this data is essential to determine the injector's coefficient of discharge (Cd). The Cd is a measure of the injector's fluid flow efficiency between the tank and the combustion chamber. Additionally, through multiple tests, the proper oxidizer fill weight can be determined in order to achieve optimal engine performance.
Static Fire
Static fire is a test that is completely analogous to flight operations, except the engine does not leave the ground. The engine is fastened to a static test stand, where load cells collect precise measurement of engine weight and produced thrust. Engine weight is essential as the oxidizer fill is based off of the weight of oxidizer in the tank. Produced thrust tells us how much force the engine produced, and comparing this with the engine performance model allows us to verify our model and further dial-in the fuel regression coefficients.
Launch
Launch is the culmination of all of the work over the course of the project. This test was conducted in rural Colorado, in the pawnee national grasslands. The rocket will be fully assembled at the launch site, placed on the launch rail and filled with propellant, then ignited sending the rocket soaring through the sky. The parachute system then deploys and cases the rocket to coast back to the ground.
