The Fox 15 BB is "grandfathered" in the rules. They were the engine to run "back in the day". Then the quality became very hit-or miss, and the event really declined. The Magnum and ASP blue head engines were introduced as an available alternative 10 years ago. The .250 venturi size was selected to give similar performance to a good, but not necessarily great, Fox. The stock engine requirement and external controls requirement were added to make the event a bit simpler to get into. Then the blue head engines went away, and the SH 15 came along. We ultimately decided the SH needed a little boost in the power department, and increased its venturi size to .266. The SH has never enjoyed the success or popularity of the Magnum/ ASP, so the return of this engine is a good thing for the event. The Fora Junior is another engine we are considering, but supply issues are obviously a problem at the moment.

All that being said, a good Fox would still win. Interestingly, even the local guy with two very fast Fox airplanes prefers to fly one of his ASP airplanes.