I think he is even faster than Chuan yun  Li. Watch his right wrist, almost no movement at all!! In this video he did it in 44 seconds (from 4:01 to 4:45)! However, I think the faster it goes the less it resemblance bumble bee.  Grew up being stung by tons of mosquitoes, I thought the flight of bumble bee actually sounds more like mosquitoes especially when it's played at the "normal" speed:))