This project was the natural evolution of the Mark I hybrid rocket engine designed and first tested in February 2015. Mark I was designed to be a proof-of-concept test bed for different hybrid engine components. Titan, from its inception, was designed to be a flight-weight engine meant to be integrated into a rocket body and launched. In order to begin work on the airframe, though, the engine must be adequately certified and tested, and flight is still in the distant future.
Fundamentally, the engine is designed to produce 3,500 Newtons (800 lbs) over the course of ten seconds for a total impulse of 35,000 Newton-seconds (8000 lb-s). The engine will weigh less than 70 kilograms (154 lbs), and will be no more than 0.2032 meters (8 inches) in diameter.
The initial test is only intended to be 2 seconds. However, in the interest of learning about the initial burn characteristics, everything other than the amount of oxidizer loaded will be held constant. The engine is a hybrid utilizing solid HTPB and liquid nitrous oxide.
The Test Stand
To properly test Titan, we needed to build a strong, rigid testing platform, that would be portable enough to transport on the highway. We chose unistrut as our primary building material, and sought to build a vertical structure that could measure the upward thrust of the engine. Below the exit of the nozzle is a steel flame diverter, to prevent the structure itself from melting in the exhaust. We split the structure into three components; a base, an outer tower, and an inner tower. The base is 5' by 5' and is bolted to the ground using anchors drilled into the cement below. The inner tower contains the entirety of the engine with each component bolted in place with 1/4" bolts. To measure an accurate force reading, the inner tower is suspended in the outer tower by a 1/2" bolt through the load cell at the top, and held from shaking by lightly tightened bolts on the sides. The entire structure can be assembled in a few hours, and raised by hand, if we have enough team members on hand!
The team conducted two "cold-flow" tests in the Spring of 2017 to assure the avionics, structure, and propulsion components could all work in conjunction with each other. With those two successes, and approval from our mentors and Tripoli Houston, we conducted the first live test of the engine on 4/9/17. The test fire was a fantastic learning experience for the team, despite not being as successful as we hoped. The engine ignited and the structure held together, however, the nozzle and combustion chamber disconnected from the engine due to combustion instabilities toward the end of the burn. The nozzle became lodged in the flame diverter and suffered considerable damage.
We are planning to test again in December of 2018. After we conducted the preliminary analysis of the test, we gathered feedback from our mentors to determine our next steps to achieve a more successful burn with Titan.
Titan System - "Major tom"
While still in the early stages of development and testing, the Titan configuration has its sights set on one day flying. As such, the Titan avionics system required a radical redesign. It includes a remote datalogger, a sensory acquisition board, and over 20 different sensors. It also will control all ignition safety protocols and procedures for engine testing and launch. Earlier versions will be remotely controlled via WiFi, but Titan will eventually be controlled by radio.