I was in Clark Rubber on the weekend and spotted this huge-ass 28cm (11") funnel. It took me about 3 seconds to figure I could launch that! The build was straight-forward, two ply centering rings, a lenght of tube for a 29mm motor and a 1/4" launch lug.

To work out where I needed to cut the funnel for the launch lug, I inserted the engine mount and used a torch to illuminate the right spot on the plastic through the launch lug.

Not yet flown, just waiting for a nice day now :)