$10,000 bet for downwind faster than the wind - video

[DIYSwede]

It works, period. "-Because science!"
The wind speed difference from the surface speed powers it - no magic "free energy" involved.

Over 45 years ago, when I was still "young and promising" I read a Scientific American article* on this concept,
but instead it being a wind powered boat going straight into the wind.
It could actually only go into the wind by its very design:

It was supposed to have a pulling propeller in the water, powered by a slanting axle up to an air driven propeller:



I initially thought it just wouldn't work - neither did my buddies, calling it a Perpetual Motion device...

But, I did a proof-of-concept A-framed trimaran, from a few styro blocks, balsa wood and propellers from a hobby shop
(remember those? I. e. the Hobby Shops - not the propellers!)
and ran it half-successfully powered by a decent room fan in the 25 ft long foot washing basin at a gym.
At the start it just drifted downwind, but as its propeller picked up speed it started chugging itself into and upwards into the headwind.

Looked kinda silly, but it sorta worked to the amazement and laughter of my critical friends.

-"It verks!":



Still remember the "The Push-me-pull-you boat" title of the article,
which apparently came from Scientific American [Martin, Sci. Am. 233 (No. 12), 125( 1975)..]
(which I back then occasionally read at the city library),
and I could even found an online analysis of of it this morning (the article, stupid - NOT the library!):
AJP_pushmepullyouboat.pdf



Ah- yes: Some ice boating friends have no problems going 55 mph tacking in a 10 mph wind either.

And Rick even drove into the wind too:

* SciAm article on pg 6 & 7 of this: https://www.jstor.org/stable/2494996...o_tab_contents

PS: Anybody thinking a wind-driven craft could reach over Mach 1 (in ANY direction) is only "not even wrong".

BONUS: Any other intrepid, "free-thinking" HMT:er who also wants to try and prove these simple water tricks: