[vacri]

I don't know if we're talking about the same guy and the same forum, but I remember a very similar story on a forum I used to frequent. The guy also had a plan for interplanetary spacecraft propulsion, that involved a weight moving to the back of the craft, being thrown towards the front of the craft where it's caught, and repeating the cycle.

The theory in his mind depended on there being a difference between the weight being 'thrown' and merely being 'moved and released' towards the front of the craft. It took a few patient techies, one of whom was a professional physicist, quite a while to explain that there was no physical difference between 'throw' and 'release'.

Nice bloke, but a classic example of 'not being able to talk the talk', as discussed in the article.