Pachacuti Mk.1.1 FF Rocket Engine

thingiverse

I conceptualized this project as a personal challenge, and it's the initial iteration of a scale model of a full flow methane oxygen rocket engine that I envisioned myself. I referenced existing engines to inform its design, drawing heavily from the SSME and BE-4 engines. The model features a fully detailed interior with modeled turbopumps and injector systems (I can upload the individual components if there's interest in them; note that there are over 500 components, but I could share the main ones and primary sub-assemblies upon request). One reason I embarked on this project was to make it accessible for any student interested in aeronautical engineering. You can view a related thread here: http://forum.nasaspaceflight.com/index.php?topic=39200.msg1468297#msg1468297 The designs are also available as sheets there, providing insight into the engine's inner workings. Print Settings Printer: Notes: I suggest orienting the model so that the nozzle is always downward-facing (larger end on the ground) to minimize scaffolding usage. Post-Printing If printed in two halves, you can glue them together. How I Designed This I spent several months studying engines and compiled a notebook detailing many of the processes and mechanics involved. After gaining a solid understanding of the engine's operation, I meticulously modeled its components using CAD software before assembling the engine. I'm pleased with the result, but I'm currently planning an upgraded version to improve it further. Misc. How it works: The Pachacuti engine is a prototype bipropellant (two-propellant) model that I've been designing. It utilizes cryogenically frozen fuel (i.e., fuel kept at extremely cold temperatures, with oxygen below -218 degrees Celsius and methane below -182 degrees Celsius). The engine operates on a full flow staged combustion cycle: both propellants pass through two preburners and are partially burned using a smaller fraction of the opposite propellant. This results in an oxidizer-rich gas and a fuel-rich gas. The hot gases drive a turbine, which powers a shaft connected to two more turbines (impellers) in the centrifugal turbopumps that increase fuel pressure. These turbopumps drive the fuel into the preburners and engine; the fuel turbopump is driven by the fuel-rich preburner, while the oxidizer-rich preburner drives the oxidizer turbopump. After driving the turbine, the hot gases enter the main combustion chamber, where they are ignited together and fully combusted before being ejected into the nozzle. The nozzle's shape forces the resultant exhaust gases out in a supersonic flow, generating massive thrust. The nozzle heats up rapidly due to its inability to dissipate heat; thus, the inside of the nozzle is lined with capillary tubes. These four helical structures carry cold liquid methane from the turbopumps, cooling the nozzle significantly and allowing the methane to expand quickly before being sent at high pressure to the preburners.