Though I've sensed in the past that cooler temps offer better flight performance, I guess I'd never flown the same plane enough in varying weather to make the kind of comparison seen yesterday. Though it was a few degrees warmer, it was significantly dryer and the performance was notably better on my gas engine. I asked one of the glow profile guys who is a very good pilot and a retired airline pilot if he sensed much difference yesterday and he hadn't.

After reading the explanations... I'm now wondering if the barometric pressure played a part along with the dryer air and together they produced better performance. The glow guy wouldn't sense any change in barometric pressure because of no metering circuit in carb that depends upon it.

If the pressure was greater (most likely given our weather) the carb mixture would have gone slightly richer due to the influence on the metering circuit. At any rater, the engine was tuned back at the first of May when temps were cooler and perhaps should have been adjusted richer after temps moved from low seventies to upper 90s. Perhaps I've been running a touch too lean the last month.