The German MW 50[1] used a mixture of methanol and water. It could be fitted to the BMW801 (Focke-Wulf Fw 190) and the DB 605 (Messerschmitt Bf109) engines.
There was also the GM-1[2] which was a nitrous oxide injector and mostly used for high altitude work.
Water methanol injection was invented by Sir Harry Ricardo, a British engineer.
It is my understanding that his book "The High Speed Internal Combustion Engine" was the definitive text on the topic of internal combustion engines in the 1930s and 40s.
