What magazine was it published in?
FB,
They were from the May 1974 issue of American Aircraft Modeler. Seems they held a design competition by publishing an outline drawing and specs of a proposed model and asking readers to submit a plan/construction article of their built and flown version. One of the requirements was that the model be flown at the 1973 Nats in Oshkosh!
There were two winners, Howard Mottin and Bruce Lund, and both were published in May 1974. Personally I preferred Bruce Lund's version shown below.
As usual, if anyone would like the article scan just let me know.
Ray