Originally Posted by Doug Sams

Actually, you're not far off. The old Apogee motors used a piece of wire, maybe 1" long, dipped in pyrogen, as staging aids. I've never used one, but have the motors and staging ignitors at the house waiting for me to finish one of those long, long-neglected projects

I like Carl's idea better, tho. My take was that, while the staging ignitor provided a conduit for getting the sustainer lit, it also blocked the nozzle at the same time. In my mind, I always wondered if that wasn't sorta robbin' Peter to pay Paul.

Painting a thin coat of pyrogen in the nozzle makes way more sense to me. But it needs to have a low flash point. Some of the pyrogen I've worked with is optimized for its burning properties more than its ignition properties, probably because APCP is so hard to light. But in this case, with BP being relatively easy to light if you can just get the heat/flame/hot particles on it, the key is have a pyrogen that flashes quickly. (IMO)

Doug

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