Hybrid rockets have recently become a more and more desirable method for small satellitepropulsion, due to their lack of safety issues compared to their liquid and solid rocket
counterparts. A major reason for this is because the fuel and oxidizer are both separated
by distance and state when stored in a hybrid rocket. This also makes it relatively more
difficult to ignite and start up the rocket. While many igniter systems have been invented,
currently no reliable, self-igniting system has been flown. Recently, a Hydrogen-Oxygen
torch was designed, built, and tested in UC Davis’ Energy Research Lab. Methane is
typically used in torch igniters for lab-scale testing of hybrid rocket motors. A side-by-side
comparison on the same igniter system between Hydrogen and Methane as the igniter fuel
was done to investigate which, if any, fuel can exhibit better transient and/or steady state
performance. Due to the higher heat of combustion, adiabatic flame temperatures and
theoretical characteristic exhaust velocities when reacting with Oxygen, Hydrogen was
found to have more reliable and repeatable ignition transients. The solid fuel regression
rates were also found to be higher when using Hydrogen despite competition to burn
with Oxygen between Hydrogen and the solid Nylon-6 fuel. These performance benefits
come at the cost of being less volumetrically efficient than Methane as Hydrogen has a
significantly smaller density at a given temperature and pressure.