I built those before I was a teenager. It was greatly frowned upon, normal kids stared at the TVSame here. I grew up in a time and place where normal teenage boys would be building match head rockets and pipe bombs, with no intent more nefarious than setting them off in an old sandpit just to see how big a bang it would make. And yeah, I built a flamethrower once, too. I bet many of the Apollo engineers had a similar background to mine.