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# Thread: \$10,000 bet for downwind faster than the wind - video

1. ## The Following 3 Users Say Thank You to Jon For This Useful Post:

NortonDommi (Jul 3, 2021), nova_robotics (Jul 3, 2021), Scotty1 (Jul 3, 2021)

2. I have seen a number of videos about this and it is amazing that an academic 'professor' of physics could not understand the logic. Did he not watch the past couple of America Cup series? Boats have been sailing downwind faster than the wind for a while now,(a bit different I know but still a thing).
This is a real world example of a U.E.I. encountering the real world. Good on him for paying up.

3. I watched it until 1:07 when the brought in that wacko Bill Nye guy.

4. Originally Posted by jimfols
I watched it until 1:07 when the brought in that wacko Bill Nye guy.
Wacky but Brilliant!!

5. I dunno. I'm still having a hard time convincing myself that it works. Sailboats going faster than the wind (at an angle to the wind) makes perfect sense. This contraption, particularly when moving in the same direction as the wind? That's a whole other meatball.

6. I got ya. Bill Nye wants everyone to think he is a scientist. He is not. He has a degree in mechanical engineering. That doesn't qualify him to scold us about cataclysmic climate change. It was really painful to see him but I soldiered through it because I was interested in the experiment and the wager. I also thought about a sail as an airfoil which propels the boat faster than the wind speed. The treadmill sort of looks convincing but it seems like something for nothing. In other words if you give it a head start with a push in a calm, on a smooth surface, according to the treadmill experiment it should accelerate on is own. It kind of looks like a perpetual motion machine. I know I'm opening myself up for some criticism. I really am not a math genius and I didn't really understand the problem from that angle. For sure it is solvable with math if the problem is set up right. Was it? I don't know.

7. If you have a starting gear of 30 teeth spinning at 10 rps and another gear downstream of 30 teeth, it doesn't matter what the gears are like in between. The last 30 tooth gear will spin at the same rate as the first. So with a 1 to 2 ratio the last (gray) gear spins at 5 rps.

8. The Tread mill experiment does not constitute perpetual motion since an electric motor powers the tread mill.
There is another example of a small force generating a large lifting force with propeller and it's called the Autogyro. A smaller propeller pushes the aircraft through the air. The air drives the much larger top propeller with enough speed to keep the aircraft airborne. I know this is not the same problem since the autogyro has an engine, but still the main lifting force is not engine driven. I often underestimate the power of properly designed airfoil.

As for a mechanical engineer not being a scientists, that a new one to me. Weather and climate is all about thermodynamics and fluid dynamics period. And among all disciplines, mechanical engineers study both with heavy emphasis on thermodynamics. Heck, that was half of my graduate courses! Thermodynamics is often considered as a weed-out course, as many can't handle it and change majors or dropout of engineering after the first course.

9. ## A propeller driven sail boat straight into the wind, too...

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:

10. I realize the treadmill is a powered device but just think about it. If you place the vehicle on a smooth surface with no wind and push the vehicle as fast as the treadmill belt is traveling, the relative motion between the surface and the vehicle are the same. I bet \$10,000 dollars the vehicle would not continue to travel much less accelerate.
Also, a mechanical engineer does not constitute a climate scientist or scientist of any kind in spite of learning some thermodynamics.

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