Hybrid Rocket Engine

The tinkering with solid fuel and TVC-guided rockets led me to the initial concept of what would eventually become the Asteris 1A rocket engine. I wanted to build an orbital-class rocket. At the time, this seemed realistic since I knew very little about orbital mechanics, liquid rocketry, the complexity of rocket systems at that scale, etc. But it gave me a goal to work towards. As research began, I looked into a hybrid motor to get a sense of design and learn basic rocket engine principles. For reference, a hybrid motor is typically a solid fuel grain with a gaseous or liquid oxidizer flowing through it to accelerate its burn. I learned basic nozzle theory using rocket propulsion elements, and through online forums, I knew enough to piece together a design for a gaseous oxygen-rubber hybrid rocket engine. At the time, I had little knowledge about how much thrust this small engine would produce. The estimates were 50 pounds. It was designed to have a steel casing and nozzle with an aluminum injector. The injector geometry was a simple spray nozzle to inject high-pressure gaseous oxygen into the fuel grain for combustion. The only part I had manufactured for this particular engine was the standard De Laval nozzle portion which I turned out of some round steel stock. I halted development of this engine because I realized I would never get the thrust results I was looking for using this hybrid setup. The solid fuel that was commercially available didn’t have nearly enough energy density. In addition, I would only be able to fire the engine once before needing to replace the fuel grain.

Image: Hybrid engine CAD render May 29, 2019 Image: Hybrid Engine Nozzle, July 11, 2019