UMBRA Successfully Terminates Liquid Engine Hot Fire After Only One Year

By Luis Azuara, May 17, 2022

Cal Poly Pomona’s Undergraduate Missiles, Ballistics, and Rocketry Association successfully launched its first liquid engine on April 30.

Aerospace engineering students James McPherson, Kaitlyn Pitugnarongphor and Jacob Liebgott were able to complete something that had never been done at Cal Poly Pomona in just one year independently.

The original idea for the project began two years ago, but after a long preparatory work, this small group of engineers from UMBRA Propulsion felt it was time to start working on a liquid rocket engine. .

UMBRA is an on-campus engineering club with over 200 official members. The club holds several project teams such as NASA Student Launch, Friends of Amateur Rocketry competition, experimental and UMBRA Propulsion – which is the team that designed the liquid engine.

UMBRA Propulsion primarily runs on solid propulsion, but after lots of practice and experience with solid motors, the team felt it was the right time to switch to liquid propulsion.

“We had just won our second competition in a row among friends of the amateur, and it (solid propulsion) was starting to feel easy. Our UMBRA-powered team members felt like we were just rinsing and repeating the same thing,” said McPherson, chief engineer. “So our natural next step was to move to liquid propulsion.”

In a solid rocket, powdered fuel and oxidizer are mixed into a solid propellant that is “easy”, according to McPherson. With liquid rockets, there are valves, regulators, wastegates, reservoirs, and many parts to consider that go into liquid engines.

Currently, most universities do not have liquid rocket capabilities. Schools that have liquid rocket capabilities typically have hundreds of thousands to millions of dollars in funding and dedicated lab space. The small team was able to develop the engine for the most part in McPherson’s living room.

The purpose of this first fire was to start a liquid engine. McPherson, Pitugnarongphor, and Liebgott wanted to see if they could accomplish something few colleges do.

“This whole project serves as a scout to test the feasibility and see if we can get funding and lab space to move to liquid propulsion,” said test bed engineer Liebgott.

With help and funding from Exquadrum, Inc., McPherson, Pitugnarongphor, and Liebgott were able to build the engine from start to finish in just one year.

Exquadrum, Inc is an aerospace and defense company based in Victorville, California. McPherson had already been a trainee for them and Exquadrum was ready to help with the engine design. The company’s contribution was the construction of the thrust chamber. This was a huge contribution, because thrust is what moves the rocket through the air.

Within an hour, the engineering team set the engine on fire. What made this possible was a cart built by Pitugnarongphor. Pitugnarongphor was the construction engineer for the project. The cart allowed the team to deploy the engine, bolt it to the test bed and fire it up within an hour.

During the hot fire, the liquid engine was able to generate up to 423 pounds of thrust with a chamber pressure of 312 psi. The team had a goal of 400 pounds of thrust.

With this achievement, CPP students can see that liquid propulsion is possible.

“The reason we fly as students is so different from the reason SpaceX flies. SpaceX flies because it has customers. We are students, nobody is going to pay us to launch stuff, but we we’re always throwing stuff out because of inspiration,” McPherson said. “With this engine, we compete with Purdue, USC, UCI, Georgia Tech, etc.”

What this project does is help future engineering students. According to McPherson, CPP now has a product that rivals the work of these prestigious undergraduate collegiate propulsion teams.

For this project, the team received no assistance or funding from Cal Poly Pomona staff or resources. The project was independently funded, created and manufactured by the team.

“I hope this accomplishment helps us get more funding because liquid rocketry is the future of rocketry as a whole,” said Rochelle Casement, UMBRA president and aerospace engineering student.

For more information on UMBRA, please visit their website and on Instagram.

Feature image courtesy of UMBRA.

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