Fro my money one of Edgar Westbury's prettiest designs, the 15cc overhead valve "Kittiwake" was first published in plans form in the 1930s, although the great man didn't actually get around to a detailed writeup in the "Model Engineer" until 1944 - the result, he explained - of waiting until a comprehensive test program involving the engine had been completed.
This engine is nicely made and turns over freely. Unfortunately, during a long period of static display on a sideboard it was dropped onto the rocker cover, fracturing the casting (which just goes to show that the way to maintain engines in good condition is to keep using them). Fiddly to fix, but worthwhile - as well as being a good-looking engine, Kittiwakes are getting rather thin on the ground these days.
Height 7 inches