D12-3's Near Non-Ejection Events Prevented!!! This is the top end where I learned the hard way about D12's sometimes have not-enough Ejection charge and too thick of a ceramic cap. After a "lawn dart" event with a fully intact ceramic cap 2(?) years ago, I started cutting an "X" into the top of the ceramic to where I "just see" some BP, then stick masking tape over the ceramic and onto the inner wall of the casing and trimming off with an X-Acto knife. Since then, D12's have worked like a charm, most of the time the ceramic completely blew out like it should upon ejection, but some of the time like recently, the ceramic was Not fully blown out but at least enough of the Ejection charge went through to push out the parachute and nose cone. Both motors from the same pack (and manufacture date code) had the same behavior recently. If I had not done this, I think another lawn dart and ruined rocket would very likely have happened again. In the past, I have X-Ray'd D12's and what I found was if there is less BP ejection charge, there will certainly be a thicker layer of ceramic on top which is a double whammy leading to non-ejection events. I have a theory that the motor-making-machine (Mable?) has a fill-sensor that stops filling ceramic in at a specific level which means less BP ejection charge leads to more ceramic being filled in until the fill sensor says "stop". Someone here will likely say "that's not safe", but after a LOT of fully successful launches and ejections, that is Way safer than a lawn dart coming down to someone possibly not seeing the rocket coming down nose first and fast.
