Rocket Propulsion

Subgroup 2 – Rocket Propulsion Group

In our group, we have been focusing on developing hybrid rocket propulsion for the past decade, mainly because of its highly safety and simplicity, in addition to its throttling capability similar to, but lower Isp than, liquid propulsion. Recently, we began to be interested in developing liquid rocket propulsion to explore even higher Ispand more controllable O/F ratio. Major research momentum and resource comes from ARRC (Advance Rocket Research Center), which was established by Prof. Jong-Shinn Wu at NCTU in 2012 with the generous donation from private sectors. The major projects of this group are summarized as follows:

  • Design, build and test of L ~ M class of sugar (Sorbitol-Potassium nitrate) rocket engines: Until today (2018), the team had launched more than 20 APPL-series rockets which was used as training and test platforms for new students and conceptual verification of component/subsystem of other missions, respectively. For example, relatively matured parachute deploying system and stage separation mechanism have been developed by using this APPL-series rockets. The max altitude reached by these rocket is about 1,000 m which was limited by the launch environment.
  • Design, build and test up to an R class (4,000 kgf) hybrid rocket (HR) engine system. Regular research activities include numerical analysis, full-scale hot-fire tests and flight tests for verification of the design. Either HTPB or plastics (HDPE, Nylon, PP) can be used as the fuel and either N2O or H2O2 can be used as the oxidizer. A ground Ispof 240 s (vacuum Ispof 295 s) of some type of HR engine has been reached in our group. The team had accomplished 4 HTTP-series flight tests of hybrid sounding rockets (HTTP-1, HTTP-2a, HTTP-2b, HTTP-3S). Currently, a two-stage HTTP-3 hybrid sounding rocket project from MOST was recently granted which aims at launching the rocket up to 100 km by 2021. Many on-going research subjects include developments of:
    • N2O igniter
    • blowdown type N2O/PP HR engine
    • throttling H2O2/PP HR engine
    • ethanol/H2O2 liquid rocket engine
    • turbo pump system using H2O2 gas converter

For details, please visit the following two websites:




  • Design and Modeling of advanced parachute recovering systems for human, payload and burned rockets using fluid-structured interaction numerical technique.



Hybrid Rocket Engine Development (Single port engine w/ mixing enhancers)




1000 kgf Hot Fire Test (Snapshot)


Hybrid Rocket Engine Development (Dual-vortical flow engine)


Rocket Engine Application Development (Quad-Monopropellant Engine Levitating Platform (4-MELP))


Rocket Engine Application Development (Quad-Hybrid Engine Levitating Platform (4-HELP))

4-HELP is designed to produce a maximum thrust of 240 kgf with 60 kgf of thrust for each of the four rocket engines. It is equipped with four combustion chambers, four running tanks and two common pressurant tanks. Due to the insufficient of torque supplied by engines, which is necessity for yawing, cant angle installation is applied to all four engines of 4-HELP. Nitrogen is used to pressurize oxidizer stored in running tanks. 90% purity of hydrogen peroxide is used as oxidizer, and the fuel was chosen to be plastics.