Proxima Engine

Isometric View

Section View

Proxima is Eclipse’s ground test hybrid engine; it is a 10:1 scale model of Titan II by impulse, produces 92 lbf of thrust, and exhaust velocities exceeding Mach 2! The engine was first conceived for three main reasons: to gather more accurate data for large engine development, achieve high testing cadence with full and rapid reusability, and iterate on a variety of new components with high modularity!

Proxima resembles Titan II much more than its predecessor, Luna, incorporating many of the same engine components such as the fuel grain, injector plate, and nozzle assembly. Its 10:1 scale of Titan II by impulse was an intentional design choice to mimic this as well. In addition, it has twice the thrust of Luna to better highlight the impact of any design change on its output thrust. All this allows for more accurate data collection for engine development that can be applied directly to Titan II’s development!

Proxima, as well as its test stand, was designed for ease of assembly/disassembly and machinability. All of its components are connected through simple interfaces that can be connected and disconnected within minutes. This expedites fuel grain replacement to allow for multiple hot fires in a single test day. It was also designed to simplify parts and reduce the number of necessary machining operations with its failure point strategically placed to save all of the components with the highest cost and machining time. In the event of an engine failure, this also allows for a quicker turnaround time when fabricating new engine components. These features will yield a higher testing cadence as the engine was made for full and rapid reusability!

Proxima also exhibits high modularity as each engine component exhibits maximum simplicity and can readily be swapped out for a new one within minutes. On top of quick turnaround time, this allows for testing of a variety of new components and ease of redesign which maximizes the space for iteration and optimization. All this knowledge gained from testing will converge on a handful of optimal designs that will then be implemented on Titan II for maximum performance!

The components will also be more robust in the event of an anomaly. The club has conducted a thorough failure case analysis of Proxima to ensure that the failure point of the engine would be the bolts going through the injection bulkhead to the upper flange of the combustion chamber. These bolts have been sized to fail at 1050 psi during an anomalous overpressurization. To validate the results, a thorough FEA stress analysis has been conducted on the engine components to ensure that a factor of safety of 2 is maintained even in worst case failure. The club believes that in the event of a failure, the vast majority of Proxima will remain intact.

The design process of a new rocket engine is an invaluable engineering experience for all involved; with this in mind, Proxima’s objectives align seamlessly with the club’s overall mission of expanding our knowledge base of all things rocketry!