Having some small acquaintance with the brand, I never met a Cox design that wouldn’t fly. There were problems with some, but with two exceptions, power to weight was not a problem. The losers wer the Hyper Viper electric models (NOT the Hyper Viper stunter that Mike Pratt designed, that was a winner)
Stability wise, they all got retuned early on in my watch so they would fly smoothly with your hand locked to your chest. The only one with no room for correction was the P40. But Bart Klapinski could fly 3 of them at once!
A couple had “peculiarities”! The Fokker Triplanes would do an unrecoverable (we had a pile of scrap to prove that) outside tumble if you input down too fast. The TD4 would flex its wings and do a death dive if, again, you input down too sharply.
The Stuka was a great flyer and capable of loops, but very fragile. Sad!
I could do a (large) square loop with the PT19. And every maneuver in the modern pattern with the Me-109. The Hyper Viper stunter was pattern capable too.
Of course I didn’t deal with all 50+ years of Cox planes, but in my experience, flight performance was a consistent requirement. The story goes that early on, Roy Cox insisted on making the first test flight on each new prototype. If you wanted to keep working there, it better fly!
