Yes, they sound very similar to a glow engine. Most are surprised when you tell them it's not glow but gas. Probably what you're hearing on the video is a 13-6 or 7. When I upped the size on mine, the sound level didn't change that much but the performance did fall off noticeably. I have the Big Stik 60 (Great Planes) and installed the bigger brother GX15 and while it flew just fine, the noise was still of a 2 cycle glow and changing props had the same result: started with a 13-6 and it went like gangbusters. Switched to a 14-6 and she really slowed down.