Ellis Forced air burner questions

[Ken Kelley]

I'm building one of Darren Ellis's forced air burners and have a couple of questions. 1) Is there a pipe or nipple extending into the body of the burner for the gas supply or does the gas just flow through the close nipple which attaches the gas shut off ball valve? If a pipe is needed, what size orifice is required? 2) Is a tapered nozzle required on the 1" burner pipe entering the forge?