Is there a recommended size for the port (core) in a moonburner? What ration of port diameter to propellant diameter would give the most neutral burn? (I am using the term moonburner to indicate a single offset port grain with the edge of the port touching the edge of the propellant. Not a c-slot).
Also, a more general and related question - if I wanted to design a long-burn 54mm EX motor for a saucer with a 6 - 8 second burn time, in the
1000 NS range, what grain geometry would you recommend? The main requirement is that the case not melt through! I have been trying to think of ideas for an end burner with a very fast propellant, but I just don't think it will work. I'd need so much insulation at the aft end (reducing the diameter of the exposed aft end, even with a slot or small core for a spike) that the initial thrust wouldn't be high enough to lift the saucer+motor. I think I'm going to have to go with a moonburner or D-slot.
Thanks.
-- David