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Old 07-22-2010, 07:01 AM
jdbectec jdbectec is offline
the middle-aged rocketeer
Join Date: Sep 2006
Location: Urbana, Illinois.....the birthplace of HAL
Posts: 449

Originally Posted by blackshire
I believe the old Teleflite book on "roll your own" black powder model rocket motors also touched upon this issue regarding core-burning motors.

From LeeR's recollection (I wish *I* could honestly wear a "I Toured the Estes Plant and Didn't Get Blown Up!" T-shirt!), it sounds like the B14 motors were manually drilled out. An automated system using a "magazine" feeder and a relatively slow drill (with a non-ferrous metal bit) could drill out B14 motors, and the leftover black powder drill "dregs" might even be reusable (if they could be safely "re-powdered" to the required mesh size) for propellant grains in other motors.

While I can't comment directly on the B14, Lee Piester told me the old Mini'Max core burners were drilled, IIRC, using some kind of fixture and a horizontal boring machine. He also mentioned one would occasionally ignite! This prompted the move to Enerjet composite motors, much safer.

Using a pintel requires more than one ramming head, no big deal using the Teleflight methods, but not suitable for "Mable" type machines.

Terry Dean or Fred Schecter should chime in, as they are more knowledgable about this than I.

For the record, I BELIEVE, some type of binder is used in BP motors to ensure they form a good grain, something I remember from a MSDS(?) I read.

Of course I'm no expert either, and I could be wrong about all of this, I've been wrong before.
Jeffrey Deem
CIA section 527
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