In the very early days of pattern the Veco 61 was the hot engine (no muffler of course), then late 60s the Webra 61 Blackhead (a very distinct Webra sound coming back to idle on the down wind landing leg), then the Kraft K.61 now updated by RJL (RJL is doing an awesome job on this engine) and the big power house the OS 61SF ABC-P (big prop and pitch, pipe and rocket like speed).