HYBRID ROCKET MOTORS

IGNITION METHODS FOR HYBRID ROCKET MOTORS


There are several methods available to ignite hybrid rocket motors, both for commercial and amateur / highpower / model rocketry. The following list is not exhaustive, but provides an overview of many of the most common hybrid ignition methods.



Pyrograin Ignition

The most common method of hybrid motor ignition is the pyrograin ignition method. In this ignition method, a pyrograin is fitted to the injector end of the combustion chamber, and an electrical igniter is fitted into the pyrograin. At ignition, the electrical igniter fires, igniting the pyrograin and in turn igniting the oxidiser and the fuel.

In the case of hybrid rocket motors using a plastic fill tube, the plastic fill tube is run through the pyrograin, so when the pyrograin ignites, it acts like a pyrovalve, thermally cutting the plastic fill line as well as igniting the oxidiser and fuel.

Example Hybrid Motors: R.A.T.T.Works, Skyripper, West Coast Hybrids, Contrail, Aerotech



High Current Ignition

High Current Ignition of hybrid rocket motors involves passing a high current through a resistance wrapped around a plastic fill tube, in an oxygen rich environment to ignite the fuel and oxidiser. This ignition method makes use of an external gaseous oxygen supply to fill the combustion chamber with gaseous oxygen. A high current is then passed through a resistance coil placed at the injector end of the combustion chamber, causing thermal breakdown of the resistance coil. The coil heats up white hot in the gaseous oxygen rich environment in the combustion chamber, cutting the plastic fill line and igniting the fuel and the oxidiser.

Example Hybrid Motors: R.A.T.T.Works, Skyripper, West Coast Hybrids



PIC Ignition

In the PIC ignition method, a specific number of wraps of PIC are made around a plastic fill tube at the injector end of a hybrid combustion chamber, in hybrid rocket motors where the oxidiser tank is filled by the plastic fill tube. An electrical igniter is attached to the PIC, and the assembly is sealed with tape. When ignitionis initiated, the PIC ignites, cuts the plastic tube and ignites the oxidiser and the fuel.

Example Hybrid Motors: R.A.T.T.Works, Skyripper, West Coast Hybrids



High Voltage Ignition

The High Voltage Ignition method is used for hybrid rocket motors where the oxidiser tank is filled via a metal fill tube (e.g. the Hypertek hybrid rocket motor system). The High Voltage ignition method involves injecting Gaseous Oxygen from a small external Gaseous Oxygen tank into the combustion chamber, and then initiating a high voltage electrical spark for ignition. In the oxygen rich environment, this results in rapid ignition.

Example Hybrid Motors: Hypertek



Additional Hybrid Web Pages

For more hybrid information on this website, the following web pages may be of interest:



See Also

Hybrid Rocket Science, Hybrid Rocket Help Clinic, Amateur Hybrid Motors, Amateur Liquid Rockets, Guidance, Gimballed Motors, Launch Controller, UK Rocketry Vendors, UK Rocket Groups, UK Space Organisations