Here are the first 20th century references to foam in my Radio Control Modeler (RCM) collection.
- A two-part article on Foam Wings published in June and July 1967.
- RCM Published a Book "Foam Wings" in late 1971 (attached in four zipped parts).
- An article (packaged with the editorial) from the August 1974 issue introducing the use of foam board.
- The first two-part article on foam aircraft construction, published in April and May of 1975.