Thank you very much. I knew to go parallel and will dip pyrogen to ensure ignition. As for launch system, it should be here Monday and I will do a dry run with igniters. I am curious to see if it has the current to fire all igniters at once.
Hello and welcome!
I have that exact same ignition system (different manufacturer's label though) and have used it many times for both family fireworks shows and rocket motor static tests. Each receiver box has four connections for ematches. Each conex will fire three ematches in series** and will likely handle four; I haven't tried.
I don't want to be a doomsayer but these systems are designed to fire low-current (
ca 0.5-1 amp), low-voltage (1.5 v) ematches. CTI motors use ematches for ignition, but other commercial rocket motor starters require significantly greater current and voltage to ensure ignition***. Even with fresh batteries my system ignites higher-current motor starters slowly, or not at all. Which for clustering is obviously a serious issue.
If I was trying to ignite seven motors simultaneously with this system, using higher-current motor starters instead of ematches, I would use a separate receiver for each starter and hit the "All Fire" button. Reason: each receiver has four AA batteries in series for 6 volts. That's barely enough voltage for most commercial starters. Wiring two starters in series would drop the voltage to 3v through each starter; too low. Wiring starters in parallel means that the batteries would have to supply twice the current needed for a single starter. I think that would slow down ignition even more. And using two separate conex on a receiver would be the same as wiring those two starters in parallel.
Frankly, I don't know of a good solution. Possibly the receivers could be powered by 12v instead of 6v; that would require a bit of wiring and might toast the receiver. Wiring in a 6v gel-cell or a big lantern battery or a second set of AA batteries in parallel to increase the current available might help. Regardless, careful testing would be necessary.
**Addressing the series-vs-parallel argument: commercial motor starters that require relatively high voltage and current should
absolutely be wired in parallel, with a hefty battery to supply the necessary current. However, PROFESSIONALS wire commercial ematches in
series for simultaneous ignition. It's proven technology and has been done that way for decades.
When the choice is between "here's what's been used successfully for simultaneous ignition, by professionals, for many years" and "we wire high-current starters in parallel, so we
should do the same for lower-current ematches", I would recommend going with the professionals.
***Dipping an ematch into a pyro composition to make a low-current starter is an alternative...IF the dipped ematch will fit through the nozzle. Most F, G, and even H motors have pretty small nozzle throats...
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