This issue snuck up on me since, at the time of receipt, their website doesn't indicate it's out. The issue is primarily dedicated to BALLS 21, which was conducted in September 2012 at Black Rock. My favorite article is Ken Good's 10+ year saga about the development of a motor feed staging rocket. The concept is an extension of the rack rocket concept. That is, it is a rocket with multiple engines in a single airframe. In short, the rocket boosts on one motor and, after burn out, pressurized gas ejects the motor and pushes the stage two motor into place. While I have no personal interest in building anything like this, it was interesting to see the determination and engineering that went into his rocket, which flew successfully at BALLS 21.
There are also two articles out of Tripoli Australia and a build article on a motor test stand. Schematics included.