Have i got it right?

[Trenman]

Re: 38mm reload cases

Does 1G= 38/120
2G= 38/240
3G= 38/360 etc....?

Is this correct?

 

[hardinlw]

Literally, 1G means "one grain" and 2G means "two grains", etc. For Aerotech 38mm hardware, the case that holds only one grain is in fact the 30/120 which delivers an average 120 N-s impulse. This varies somewhat with propellent formulation. In 54mm diameter, a 1G case would produce higher impulse. For 38mm Aerotech reloads, your translation is correct and I assume that other manufacturers would be similar.

 

[The EGE]

You're pretty much right. Aerotech and Cesaroni cases follow roughly the same grain and case sizes.

For both AT and Cesaroni 29mm cases, each added grain = 60Ns, except for the 29/100 case which is weird, and the Pro29 6GXL case which is also weird.

For 38mm cases, it's roughly 120 Ns per grain for the Aerotech cases, and a tad more for the Cesaroni cases - more like 140Ns per grain.

54mm: AT 426Ns per grain, Cesaroni around the same.
75mm: AT 1280Ns per grain, Cesaroni around the same.
98mm: AT 2560Ns per grain, Cesaroni the same.

Note, though, that those are roughly the maximum impulses per grain, with an Isp of 200+ seconds. Blue propellants and stuff like Warp Nine and Imax are right around the maximum for the propellant grains, whereas Black Jack and Skidmarks get only about 2/3 of that maximum.

 

[Trenman]

Good data. Thank you for the detailed feedback.

 

[Bill P]

You can toss Loki Research in that same pattern.