Sky Ripper Systems Ground Support Equipment

Ground Support Equipment

What is GSE?
The acronym GSE stands for 'Ground Support Equipment' and for hybrids it means "The extra stuff I need to launch hybrid motors". This document will cover the GSE requirements for monotube hybrids with pyrotechnic ignition, like Sky Ripper Systems motors.

What extra stuff will I need then?
GSE like anything else, can be very complicated to very simple depending on what you want. If you fly with a club, you can use the club's 12 volt launch system to fire your motor after it is filled. This leaves you needing only very simple hybrid GSE.

At its simplest, to fill your motor with oxidizer you need the following.

A Nitrous bottle.
A solenoid
A remote switch
A 12 volt battery

Photo by Jamie Black

Nitrous Bottle

Because hybrids use the liquid oxidizer Nitrous Oxide (N20), the first thing you will need is a bottle to store your oxidizer in. Nitrous approved bottles can be had in many sizes, from a variety of vendors. A 10 to 20 pound bottle is perfect for a good supply of N20, in a container that is still light enough to easily lug out into the field.

Sources:
Ebay often has several NOS systems nitrous bottles up for auction.
Pratt Hobbies has great deals on NEW 10 and 20 pound nitrous bottles.

Photo by Doug Pratt

Solenoid

The solenoid is the valve that allows the Nitrous Oxide to flow from your bottle into your rocket motor through the fill line. The device uses magnetic force to pull open the valve, and operates on 12v DC.

Sources:
Ebay often has a wide variety of automotive solenoids up for auction.

Contact Doug Pratt for one of his brilliant solenoids. Doug has had these manufactured specifically for the filling of hybrid rocket motors!

Remote Switch
This is the switch that you will use to activate the solenoid, causing the N20 to flow into your rocket motor. This must be done remotely, from a safe distance.

The remote switch consists of:

100ft of 2 element wire (this 100 foot spool of 22ga speaker wire works great)
A momentary button
Clips to connect the ends of the wire to the solenoid
Battery clips to connect the assembly to the 12v battery

Sources:
This remote switch is easy to build yourself! The parts from Radio Shack might cost you 15 dollars.
Any existing 12 volt launch control that you have with long leads could also do this job.

12 volt battery
Connect your remote switch to your solenoid and the battery, Press the momentary button, and you will begin filling your motor!.

That is all there is to it! Now you know the simple, bare bones setup for hybrid GSE. It's really not that complicated, or expensive!

What can I do to make my GSE more feature complete?

You can:

Add a second solenoid to 'dump' the N20 from the motor in case of a failed ignition.
Add a second circuit to fire the motor.

The dump solenoid

Adding a dump solenoid is a good idea, but is not necessary. In the event of a misfire, it will take the larger hybrid motors a very long time to evacuate the nitrous from the motor through it's tiny vent hole. The dump solenoid allows you to 'dump' the contents of your motor quickly and easily if you should have a motor that does not ignite.

Photo by Doug Pratt

Firing circuit
The addition of a firing circuit would complete the package, giving you very complete fill and fire system for all monotube hybrid rocket motors.

Sources:
If you want this level of support, it makes sense to buy the RTLS-M1/M2 package from Pratt Hobbies. His system is top-notched, and has been used to fill and fire countless hybrid and solid rocket motors. Nothing compares to the Pratt RTLS system. Its all-in-one nature takes the complication out of all phases of hybrid ground supporrt, and it can be upgraded to fire pyro-free rocket motors with the addition of the GOX module. This unit can also be used to fire solid rocket motors, making in a true all-in-one GSE solution.

Sky Ripper Systems recommends the Pratt RTLS system for reliable filling and firing of their complete line of hybrid rocket motors. www.pratthobbies.com. You can also order the RTLS system directly from Sky Ripper Systems.

Photos by Doug Pratt

If you have any questions regarding Ground Support Equipment, please feel free to contact Sky Ripper Systems, or visit Doug Pratt's excellent online resource Fly Hybrids.