Nitro Gas helicopters are becoming more common among all the variuos types of remote controlled helicopters out there. Nitro helicopters use a mix of nitromethane and oil to make them go. You can find these helicopters in many different sizes: 15, 30, 50, 60, and 90. All these numbers are the sizes of the different engines. So, the bigger the engine size, the more powerful the engine lift is.
