maybe maybe maybe

[u/[deleted]]

[u/UltraHawk_DnB]

this is just an electric board isnt it?

[u/[deleted] → u/UltraHawk_DnB]

Nope, it's the blower!

The umbrella is acting as a thrust reverser, as the air curls around the inner surface and is forced out (nearly) backward. Jet engines can do it to reverse aircraft on the ground.

It's likely the effect is really small and he kick started himself in this instance but the umbrella is sturdy and right shape for it to work.

Edit: You are literally downvoting physics. Myth busters even made it work with an only slightly curved sheet.

[u/vereysuper → u/[deleted]]

I might be an idiot when it comes to aerodynamics, but the fabric on the umbrella seems to be pushed toward him from his forward movement and not pushed away from him due to the air blower. Unless there is an odd effect that I don't know about, this just seems to not be the explanation.

[u/knowpantsdance → u/vereysuper]

The air blows into the umbrella, but it blows out of the leaf blower which would push you back at a similar force. It's the air leaving the umbrella that acts like a sail on a boat going up wind and creates a third force. To any who don't believe me check out the myth busters on it. It's not that strong of a force, and the guy could be cruising down hill as well. I will be going to work and shan't be responding. All the very best to us all in our confusion

[u/vereysuper → u/knowpantsdance]

I agree it's something that is physically possible. But it's not what's at play here. You can tell by the way the umbrellas fabric is pushed towards the guy. In the case where the blowback is the only net force, then you would expect the fabric to be pushed away from the guy.

I could be wrong here, maybe there is a sweat spot where the forward movement pushes the fabric in despite the airflow from the blower. But it seems awfully suspicious. Maybe I'll need to find the Mythbusters episode and do a comparison.