Loki

Ben pointed me to this PDF in the comments section of an earlier post (Thanks Ben!)  I hadn't actually seen this before.  This is a description of the Super Loki system that uses a larger 4" diameter booster and 1.65" dart.  The earliest Loki system used a 3" booster and the dart seems to have varied from 1.375-1.5" in diameter.  Another interesting difference, from what I can tell, is that the earlier version of the dart didn't utilize a boat tail.  That must have resulted in significantly more drag, and yet the performance of the dart was impressive.  This is a photo of one of those early versions that shows the connector/coupler that presumably fits into a recess at the base of the dart.

 

In later versions of the booster (and as seen in the PDF) you can see that the connector/coupler was hollow to accommodate the boattail of the dart.