Originally Posted by GallopingGhostler

The quality in Cox engines started to slip when Estes Industries, the model rocket kit and engine manufacturer acquired Cox in 1994. They did not know how to match pistons to cylinders. Cox had a special set of employees trained to match piston and cylinders for perfect fit. Anyway, I am told some engines were a little tight, others had hardly any compression. Also they were mixing and matching performance engines with sport engine parts making them compromised performance engines. By 2004 they were selling product engines, the Sure Starts in their surplus sales outlet at $7 per pop, After, the engine division folded. Folks like Cox International, Ex Model Engines and a few others purchased the remain engines and parts stock.

There were some less successful engines toward the end of the Cox pre-Estes era. I bought their .049 R/C Bee in the early 1980's, really liked the engine. It made my Sterling Minnie Mambo on Ace R/C Pulse really fun with Ace KRD quick blip sequential throttle and was more powerful than the Babe Bee even with muffler on. I wore out a piston and liner with so many flights, I replaced the set with new. Die cast crankcase was still good, not excessively worn. But that engine was short lived. It was later replaced with the Dragonfly with greater fuel capacity.

I also bought their .074 Queen Bee back in the late 1980's. It was short lived, although as powerful as the .049 Tee Dee but with a decent throttle, was heavy and awkward to mount. I wondered why they didn't simply come up with a lighter weight .074 Sure Start styled crankcase and back with muffled exhaust throttle. Heavy is never good for a plane engine.