RELIABLE CLUSTER IGNITION USING FLASHBULBS by Mark B. Bundick, 70156,625 Flashbulb ignition has long been recognized as the most reliable way to fire clustered models. Developed by John Langford in 1971, this method virtually guarentees successful firing of clusters up to 30 motors. You will need the following materials to prepare flashbulb igniters: (1) AG-1 flashbulbs, one per engine, (2) 1" lengths of Thermalite or FSI igniter wick, one per engine, (3) 6" length of stranded hook up wire, two per engine, each of a different color (4) masking tape It is simpler to prep the igniters and tape them on the engines before installing the engines in the rocket. If you put the engines in the rocket first, it's very difficult to put in a flashbulb igniter when all engines are closely crammed together. Installing the igniters last also puts undue strain on them. Cut your igniter wick to length. Also cut your hookup wire to length before starting. Cut sufficent wicks and wires for the number of engines you intend to cluster. CAREFULLY bend the contacts of the flashbulb down. Attach the wires to the contact by twisting the wires and contacts together. You can solder the wires onto the contacts if you are careful. Using a small strip of masking tape, attach a thermalite wick to the flashbulb. The wick must be attached to the pointed end of the bulb. This allows the wick to touch the propellent grain when the flashbulb is inserted into the engine. You now have a flashbulb with a wick stuck onto the small end, and two wires sticking out the back end. Cut a strip of 3/4" wide masking tape that will fit all the way around the engine. Stick it on the nozzle end of the engine so that 1/4" is stuck to the motor, and the rest forms a " collar" around the base of the engine. Drop the flashbulb/wick/wire combo into the nozzle. After making sure the wick has contacted the propellent grain, pinch the masking tape collar onto the flashbulb to hold the bulb in place. When you've prepped all of your engines, install them in your model and finishing preping them normally. To fire the igniters, take all the hookup wires of one color and attach them to one micro-clip. Attach all the wires of the other color to the other clip. You have created a parallel circuit, such that all igniters will keep receiveing current, even if one ignites slightly ahead of the others. DO NOT CHECK CONTINUITY!!! Most model rocket launchers will set off the flashbulbs when you do. Turn your continuity key or pin at the same time you press the launch button. The flashbulbs should fire with a bright burst of light. Their heat sets off the wick and the wicks ignite the engines. ROAR!!! A successful cluster rocket lifts off. I've never had a flashbulb igniter cluster model fail to work properly. Try it on your cluster models. Persons with further questions can contact me here in MODELNET (prefered) or via E-Mail.