Hi Lou,

You did nice work, let me throw a few added facts about for you. The very large ports were designed for 50 nitro were a very large fuel flow was needed. That's why fox 15's did so well in combat. We worked many years a go with a model by the name of John Sullivan and his dieselized Cox Conquest's which employed a Cox .010 spraybar assembly and I belive a 16" prop. It won a freeflight event which was a tribute to the Good brothers radio development. Flight time was very high. As for the port thing the original schnurle porting was just the two angled ports the boost was added later to a racing .29 TWA engine for geater fuel flow thus more power. Some modeler plug the boost on the fox .61 and .74 on glow by turning the gasket 180 for more constant fuel flow during violent maneuvers.