On the experimental multi fuel engine. I remember at least 2 such articles. One was from the early 50s and was about an experimental engine made by one of the major oil companies, Shell I think it was. They were working on ways to improve fuels and get more out of the fuel.
The other article came about 10 years later, probably 1962 or 63. It featured a similar experimental engine being tested by the US Army. They wanted an engine that could run on various fuels because in military situations it would greatly simplify problems of supply, if all their engines could run on the same fuel, or if their engines could run on whatever fuel was available.
Don't remember if it was Popular Mechanics or Popular Science but it was written up in one of them.
