A long time ago, it was rubber or gas. Then the gas name stuck when glow/nitro took over. Now gas has a more accurate meaning separating it from glow/nitro. I rarely call it glow but seldom use more than 10% nitro. I will stick to it mostly because I hate batteries, and I have so many motors(engines) I still need batteries to fly rc, and don't like that, and electrics idle better so maybe when batteries don't swell up or burn I could change. I really like the simplicity and power of the glow. Leckies have not really impressed me yet, until you get to 5S but then they sell and burn.