Here's a little insight on the 1/2A Speed questions.... Most of the engines used are the CS or GZ, from China. Mr Dodge's record-holder is a homebuilt. All of the speed classes use standard provided fuel, it is 10% nitro. Back when we could use unlimited fuel the 1/2 A record was over 150, but I don't remember the exact time. Comparing records from many decades ago and today is an apples and oranges thing. The line sizes have changed considerably, and in speed flying the drag from the line(s) is way more than what the plane creates. Back in the fifties, the monoline size was .010 wire and just 35 feet long. Today the 1/2 A size is .014 and 47+ feet long, probably twice the drag. Over the decades the engine power has tripled.