Liquid fuel engine bell shape?

What is the best shape for a liquid fuel rocket engine bell, as l have a metal lathe & would like to machine my own engine bell.

mikeasaurus28 days ago

At this scale, I'm not sure that anything other than an inverted funnel would produce drastic changes to thrust. A good place to start would be based of a standard bell shape, and make extended walls along the exhaust to direct the thrust downwards.

jwzumwalt25 days ago

This link provides formulas for nozzeles