Sizes for single bell systems

[whazzatt]

I hope it's acceptable to revive a thread from a few years ago!

I'm soon to build an 8 inch J-tube system that includes an oil-barrel radiator and a brick bell.

I'd just like to check if the internal bell sizes listed in post 1 apply equally to J-tube systems as well as batch box systems. 

Thanks 

[peterberg]

There's a lot of experience regarding batch box rockets and bell systems, less so with J-tubes and bell systems. In general, the maximum ISA for any type of combustion core is firmly tied to the rate of combustion of that particular core. Experience dictates that batchrockets has a tendency to be twice as powerful as a J-tube of the same system diameter in any given amount of time.

In short: take approximately half the ISA of the 8" batchrocket's bell ISA for an 8" J-tube and it should be fine.
In my humble opinion, of course.