Hybrid Rocket Engine (Lite Saber Engine i1)

thingiverse

This is a project to build a hybrid rocket engine for a rocket I will someday build and launch in the desert. The idea is to design a good powerful engine, then stack an repeat into a 9 engine configuration for a replica SpaceX Falcon 9 Rocket. The reason for the name is due to the appearance of the first model that was painted silver and looked like a light saber from star wars. I will upload video as I go https://www.youtube.com/watch?v=tsifklldMpU&feature=youtu.be Test 1 Setup Engine-iteration one chamber and injector Nozzle-version one nozzle Fuel-propane starter and roofing tar grain Oxidizer-Nitrous Oxide "whip it's" Hypothesis: propane burn will start the burning of the tar fuel grain, then we will introduce NOS and cut off the propane and react the fuel grain and oxidizer. Results: the fuel grain never ignited. The propane and the oxidizer reacted outside the nozzle, a flashback occurred due to oxidizer and fuel mixing prior to entering the combustion chamber. The concrete nozzle held up great, and the ABS outer body was cool to the touch. Lessons learned: I had a misunderstanding about how the oxidizer and the fuel should begin reacting, and that the injector can't have fuel and oxidizer coming out of one hole, (stupid oversight) and if you want two gasses going into the combustion chamber they need to be injected separately. I also thought NOS was safer than GOX which is not true. I decided to only use GOX or gaseous oxygen with the tar fuel grain and begin the ignition/reaction with a stick soaked in denatured alcohol. Test 2 Setup: Engine-iteration one chamber and injector Nozzle-version one nozzle Fuel-roofing tar grain then "Shoe Goo" grain Oxidizer-GOX Gaseous Oxygen (2,300psi welding tank) running at 200 psi max. Hypothesis: after watching several videos on YouTube and research into oxidizes I felt I understood what I was doing for the first time. I though I would get combustion to actually happen inside the combustion chamber and that I would not get any flash back. I was hoping to achieve the matchstick pattern coming out of the nozzle. Results: The engine ignited perfectly, the fuel burned away very quickly. When going to refuel I realized that the compacted bentonite clay combustion chamber came un-compacted and the ABS outer wall was soft. I reloaded it anyway and loaded wet shoe goo for the final phase of the second test. The burn was so bright I saw white spots, and it was over pretty fast. The concrete nozzle failed the hole was 3/16 or so and ended up at 5/16 or more. The test was pretty exciting though. I achieved combustion in the combustion chamber, there were no flashback issues and I did not get the focused exhaust matchstick pattern. Lessons learned: -The combustion chamber should be made of concrete like the nozzle that was rock hard after all the firing and dropping it on the ground with no cracks or breaking. -the combustion chamber needs to be bigger to accommodate more fuel and pressure. -I need a powerful proven fuel grain that is consistent throughout all the tests, so I can focus on one variable at a time like nozzle shape. Test 3 Has not occurred yet Engine-Iteration 2 (3x larger in physical size, and 6x larger in power capacity) Combustion chamber-Gen. TWO Injector-Gen. TWO Nozzle-Gen. TWO nozzle Fuel-PMMA Acrylic rod 1" diameter with 1/4" hole 6" lengths in a chamber that can handle 12" lengths. Oxidizer-GOX Gaseous Oxygen (2,300psi welding tank) running at 200 psi max.