Actually learned to fly on an Enterprise P-51. Used an O.K. Cub .099, which isn't technically a 1/2 A, but I still have the engine, which I bough back about 1949 or 50. Last time I used it, felt it had less power than any of my Black Widow .049s. Got a lot of flying on it. I still have the very deteriorated magazine in my files, and I think I also have a copy. All sheet, buildable in a couple hours.
Actualy, a 1/2A I had a lot of fun flying was the Li'l PT, from a full size plan in the 1962 MAN Annual..
BTW, I believe I have a NIB Walker Firebird or Firebat buried somewhere in my attic. 2 piece molded foam wing, profile fuse.
Sometimes I wish I had purchased the Walker .065 engine when I had a chance. Thought it was a littl hoakey at the tme, with its latex tube and squeeze bulb for operating a clapper on the engine to give a variable speed.