of 3" ABS and used a BBQ grill igniter for the ignition spark. That was installed in one end of the ABS pipe segment which was about 3' long.

I sharpened the other end of the pipe so that I could shove a nice size russet down the pipe a couple of feet. The tightness of the potato sealed that end of the pipe.

The other end, where the igniter was located, had a screw-fit cap.

I would push the potato in and then unscrew the cap, spray a bunch of hair spray into the "chamber" and then screw the cap back on.

Once I punched the igniter button, it would launch a large potato about 100 yards.

The scouts loved it.......