graphite rocket exhaust nozzles created by the RPL

Supporting Student Success with the RPL Lab

Alex Willman  |  February 4, 2026  | Back to Powerhouse Post

On December 12, 2025, a group of mechanical engineering students gathered at the Powerhouse Energy Campus for their MECH-517 final, eagerly waiting to test fire rockets they had spent time building. Mech 517- Chemical Rocket Propulsion is a course that can be taken by both graduate and senior students pursuing their Aerospace Engineering concentration within the Department of Mechanical Engineering. The class allows students to learn the fundamental principles behind how rockets work.  

Students stand around as Manav gives a demonstration
Ciprian shows students the rocket test stand

Assistant Professor Ciprian Dumitrache teaches the classes that include a hands-on application final for students. Instead of taking an exam in a classroom, students are asked to take the information learned over the semester and apply it to their own rockets for a final grade.   

With this, the students are tasked with designing, building, and testing a hybrid rocket motor that combines solid fuel grain with gaseous oxygen as the oxidizer. Students are taught to cast their own solid fuel grain mixture using Hydroxyl Terminated Polybutadiene (HTPB) and are used for their final test. 

During testing, students’ rockets are placed onto a static rocket test stand allowing the measurement of thrust, chamber pressure, oxidizer mass flow rate, and burn time which are then used to calculate a variety of different performance parameters. Once testing is complete, students implement one-dimensional hybrid rocket performance models and directly compare them with experimental results. 

A student pouring a fuel mixture into a mold
A student holds a graphite nozzle

To make this happen, Dumitrache asked the Rapid Prototyping and Applied Engineering Lab (RPL) to machine custom graphite rocket exhaust nozzles that the student would use for their rockets. With this class being held every year, this is not the first time the RPL has machined these nozzles.  

Over many years of manufacturing these nozzles, the RPL has mastered the art of high efficiency machining and decreased time in clean up. By setting up a custom-made vacuum chamber within the Computer Numerical Control (CNC) Mill, the lab can collect graphite dust as it is machined, protecting crucial components of the mill while also reducing clean time.  

By having these capabilities at CSU and in Fort Collins, it opens endless opportunities for students to work and learn in a hands-on environment without the pressure of working for a big-time company or firm. It’s the small things that help set CSU Rams apart from the rest and why many are proud to call CSU home.