"Bret Ludwig" wrote in news: snipped-for-privacy@y43g2000cwc.googlegroups.com:
During the Korean war the army, for some reason, had a large quantity of anhydrous ammonia so they got a motorpool sergeant to build an ammonia engine. They gave him a single cylinder air cooled engine to start with and he had it running nicely on ammonia in very short time.
There was quite a write up about it in Popular Science or some similar magazine at the time but as far as I know, nothing more was done with it.
Here's a website of a company working on ammonia fueled engines today, they do give credit to the army's engine.