Interesting question. I believe small engines have outlived their usefulness. You can now buy electrics with the same performance as the .049 and .020 engines. They're alot more user friendly, alot quieter, and with the new NiMh batteries, fly longer too. Plus, small engine technology isn't really going anywhere from what I can tell. How much different is a Cox .049/.020 that you can buy today from one made in 1959? Is there any difference?? Come to think of it, why is Cox still in business? If say, OS offered a ball bearing ABN .049, I might be interested. I have their .15 CV-A, and it runs like a top. Any smaller than that, and I seem to be doing more tinkering then flying. Most people don't want to deal with the hassle of small engines. It makes more sense to just step up to something bigger, or stick with electrics. Oddly enough, go to the other end of the spectrum (30% scale, IMAC, etc), and you'll find droves of people getting into that aspect of the hobby. Yet flying fields have long since diminished from the days when the .049 was king. Makes you wonder....