Before turning this into a giant debate, I will offer to prove it's possible by a first-hand demonstration. I really want to see an episode on this. It has been as hotly debated on many forums as the "airplane on a treadmill" myth. I can also show it's possible mathematically or through several different analogies.


Clearly there are plenty of people that believe it's impossible to build a vehicle powered solely by the wind, which can go directly downwind, faster than the wind, steady state. They believe this violates all sorts of laws of physics, and constitutes perpetual motion.

The facts are:
- It can be done
- It has been demonstrated
- It's not perpetual motion
- It violates none of the laws of physics.

I can easily describe a number of ways to demonstrate this is possible. Keep in mind, the energy we're exploiting is that of the wind speed relative to the ground, not the windspeed relative to our vehicle. The trick is to develop a mechanical device to exploit that energy (which is not something for nothing).

Jack Goodman of florida did just that, and made a video of it.
http://www.youtube.com/watch?v=aJpdWHFqHm0

Many have challenged this and explain why it's a fake, but Jack has invited anyone to come see it first hand.

I just had a long conversation with Jack, and found him to be an incredibly interesting man. He's half blind, and has little education, but has a pile of patents, and is one of the better engineers I've had the pleasure to talk with.

I would LOVE to see the Mythbusters tackle this topic. I live in the S.F. Bay area, and would be happy to help out in any way possible. Jack lives in Florda, but sounds open to the idea to be involved as well.

What can I do to promote this show idea further?

The video is a fake.
"the energy we're exploiting is that of the wind speed relative to the ground, not the windspeed relative to our vehicle."
Wrong.

If you can explain this, then please go ahead. I think you may start a revolution in transportation such that the world has never seen before. How is this guy is "one of the better engineers" you've talked to - yet has little education? Most engineers have a bit of education - some have a lot.

Something wind driven can only theoretically achieve the speed of the wind - but in reality due to friction, it would never be able to fully match the wind's speed. You're claiming that it not only overcomes friction but also somehow gets extra energy and goes faster than the wind? So the vehicle would now have a head wind and yet more friction in the form of wind resistance. I can't see how this is possible.

Go ahead with the mathematical explanation.

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The video is a fake.

I assure you it's not. He's invited anyone that cares to to have a first hand look. What's the point of faking it? He's not selling these. It's not exactly making him famous.

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"the energy we're exploiting is that of the wind speed relative to the ground, not the windspeed relative to our vehicle."

Wrong.

A compelling argument indeed. But I can assure you this is exactly what's happening.

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If you can explain this, then please go ahead.

As I've said, the cart exploits the difference in speed between the wind and the ground. There's plenty of energy available there even with real-world losses. Try this little experiment. Put a yo-yo on edge such that the string exits below the axle. Now pull the string slow and steady parallel to the surface of the table. The yo-yo will move toward your fingers and roll up the string. So it moves faster than the force that's pulling it. Please don't take my word for this. Try it yourself.

Now this alone doesn't demonstrate the full principle I've described, but it's an important element of it. When you've demonstrated that to yourself it will be easy to describe how to get the rest of the way there.

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I think you may start a revolution in transportation such that the world has never seen before.

Sadly I'm sure that won't happen. There's not much practical use for this thing other than in proving this principle.

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How is this guy is "one of the better engineers" you've talked to - yet has little education? Most engineers have a bit of education - some have a lot.

I've worked with a lot of engineers over the last 20 years. I have a fair bit of education. I have a B.S. from GA Tech and an M.S. from UCLA, both in Aerospace Engineering. I'm currently Chief Scientist for a silicon valley high tech company, and I currently hold 26 patents. I've interviewed MANY engineers over the years, and I feel I can judge an engineer reasonably well.

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Something wind driven can only theoretically achieve the speed of the wind - but in reality due to friction, it would never be able to fully match the wind's speed.

That's true of a traditional sailing vessel. This machine uses mechanical advantage to do something a high performance sailboat can do - only straigh downwind. A high performance sailboat can TACK downwind faster than the wind (and iceboats do it easily). This machine simply does that in a straight line (essentially the prop tips are on a continuous downwind tack).

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You're claiming that it not only overcomes friction but also somehow gets extra energy and goes faster than the wind?

Yes. Not "free" energy, but enough "extra" energy that it can beat the wind on a direct downwind course.

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So the vehicle would now have a head wind and yet more friction in the form of wind resistance.

Yes. That's exactly right. Intuitively one might think if this were possible then the cart could simply accelerate forever. This is not the case. The cart can reach a speed of about 1.5 times the wind speed.

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I can't see how this is possible.

Go ahead with the mathematical explanation.

Try the yo-yo experiment. It will surprise you. From there I can easily show you how that can be made into such a vehicle. I will also post the vector diagram that demonstrates how a traditional sailboat can TACK downwind faster than the wind (if you like).

Don't bother with the tacking downwind explaination because faster down wind means directly downwind, not crosswind or quartering wind.

The video is faked. The propeller is turning the wrong direction. With a tailwind, the propeller would attempt to turn the other dierection. In otherwords, it would immediately act as a brake, stopping the vehicle. It will not accellerate.
That vehicle is being towed.

Another glaring problem is the first attempt. The vehicle stops. He says something like "I left the brake on." He then pushes the vehicle again. He never made any motion to release a brake. (not that there is any sign of brakes or brake controls)

Do a simple experiment. Put a free turning propeller on a skate board or some other set of wheels. Note the direction that the propeller turns with a tail wind. Then tow it. When you hit windspeed the propeller will stop turning. When you tow it faster than wind speed, the propeller will now turn in the opposite direction. That should tell you something.

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Originally posted by oso954:
Don't bother with the tacking downwind explaination because faster down wind means directly downwind, not crosswind or quartering wind.

OK, then let's try this... Let's have two ice boats side by side. They'll both tack downwind, always on opposite tacks. But they're attached by a long horizontal rod that they can each slide along. So the boats are both tacking downwind, but the rod is going directly downwind (broadside) - as is the center of gravity of the whole contraption, despite the "moving parts".

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The video is faked. The propeller is turning the wrong direction. With a tailwind, the propeller would attempt to turn the other dierection. In otherwords, it would immediately act as a brake, stopping the vehicle. It will not accellerate.

Again, the video is legit, and you can get a demonstration in person if you like. The prop is going the right way, because despite what our intuition tells us, the wheels are turning the prop, not the other way around. The wheel and drivetrain simply provide the same kinematic constraint on the prop that the keel provides to the sail of a sailboat. The tips of the prop are in fact on a continuous downwind tack, and the cart is going faster than the wind.

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That vehicle is being towed.

If you're really certain of that position, I'll offer you a much better option. Bet me $100K. I'm making that offer right here and now in front of anyone on this forum that cares to hold me to it. You might as well take my money if you're certain it's impossible.

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Another glaring problem is the first attempt. The vehicle stops. He says something like "I left the brake on." He then pushes the vehicle again. He never made any motion to release a brake. (not that there is any sign of brakes or brake controls)

He has a radio control for brakes and steering. He released the brakes from his transmitter. If you'll watch the video again you'll see that the cart began rolling once he did release the brakes - before his wife gave it a push.

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Do a simple experiment. Put a free turning propeller on a skate board or some other set of wheels. Note the direction that the propeller turns with a tail wind. Then tow it. When you hit windspeed the propeller will stop turning. When you tow it faster than wind speed, the propeller will now turn in the opposite direction. That should tell you something.

Not necessary. I agree that your experiment would turn out exactly as you describe. But that isn't a vehicle designed to go directly downwing faster than the wind. In this case the prop is geared to the wheels with the appropriate prop pitch and gear ratio.

I can offer further models and explanations (including the necessary vector diagrams), or you can take the bet.

Spork,

As much as you "assure" us what you think is happening, I think you're mistaken - badly. Go ahead with an explanation that can logically and scientifically explain this - maybe some math etc. Until then your "assurance" is not really convincing.

If you truly have all this fabulous education and 26 patents, you should know that this doesn't work or at least be able to offer a simplistic explanation beyond "I assure you."

If you have been to university, you should also know that to be a professional "engineer" by definition requires a degree from a recognized and accredited institution and generally admission to a professional society of engineers. Just because you know how to tinker with stuff and invent random things that you don't really understand doesn't qualify some backyard quack as an engineer.

I can't see the yo-yo working but even if it did it has very little relationship to the scenario you're describing. The vehicle itself needs a source of energy to accelerate above wind speed. If the vehicle needs the energy, the relevant question is wind speed relative to vehicle. If a vehicle is merely matching the wind's speed (which is impossible due to friction) it would have no relative wind at all and a propeller attached would not spin.

It's real easy to challange someone to a 100k bet, when no one knows who you are. Just as it is easy to claim engineering degrees.

I agree that the wheels are obviously driving the prop. Now explain how it accellerates against increasing forces while the relative windspeed drops. Where is this increasing energy supply coming from?

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As much as you "assure" us what you think is happening, I think you're mistaken - badly.

If so there's an easy $100K in it for you.

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Go ahead with an explanation that can logically and scientifically explain this - maybe some math etc. Until then your "assurance" is not really convincing.

My "assurance" shouldn't be convincing. My explanations and my bet should go a little further.

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If you truly have all this fabulous education and 26 patents, you should know that this doesn't work or at least be able to offer a simplistic explanation beyond "I assure you."

If it didn't work I think I would indeed know that. Rather than focusing on the words "I assure you" how about adressing the explanations I'm trying to offer.

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If you have been to university, you should also know that to be a professional "engineer" by definition requires a degree from a recognized and accredited institution and generally admission to a professional society of engineers.

I didn't say Jack was a "professional engineer". If you've been to university you'll know that very few of us that are engineers by profession are "professional engineers". I know it's a bizarre distinction, but outside of civil and some mechanical engineers, the "professional engineer" distinction is quite rare. I've been tricking employers out of a lot of money for a lot of years based only on my knowledge, experience, and advanced degrees in engineering. If you really doubt my credentials please let me know how I can prove them to you. Do you need a picture of me holding up my diplomas and framed patents? Would that convince you, or would you tell me they're faked?

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Just because you know how to tinker with stuff and invent random things that you don't really understand doesn't qualify some backyard quack as an engineer.

I don't know whether Jack would call himself an engineer. I do, and I don't see the need for insults. The man went to the trouble to do something like this to convince the doubters - not to be insulted. But I suppose it's easier to insult him than to ask for a live demonstration - and perhaps safer than taking my bet.

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I can't see the yo-yo working

I asked you not to take my word for it. Can't you find a yo-yo?

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but even if it did it has very little relationship to the scenario you're describing. The vehicle itself needs a source of energy to accelerate above wind speed.

Please try not to get ahead of yourself. I told you that once you were convinced of the principle with the yo-yo I'd show you exactly how that can be applied directly.

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If the vehicle needs the energy, the relevant question is wind speed relative to vehicle.

That's a good question. It's at the heart of this debate. What makes this (and similar) vehicles interesting is that the wind that's of direct interest to them is measured against the ground - and this vehicle can only operate with its wheels in contact with the ground.

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If a vehicle is merely matching the wind's speed (which is impossible due to friction) it would have no relative wind at all and a propeller attached would not spin.

Are you just "saying" or are you putting up $100K?

Ahhh - here we go. I found an old link to another company I'm associated with:

http://www.student-racing.com/staff/board.html

So you can see my ugly mug right there. I'm the one with the 70's porn mustache. Do I need to post a current picture of me holding a sign that says it's possible to make a vehicle that goes downwind faster than the wind?

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My explanations and my bet should go a little further.

Yeah, they should - so where are they? You haven't explained anything yet just made some claims.

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Can't you find a yo-yo?

No, I don't have any children's toys hanging around. Still, I don't see that working. The torque from the yo-yo's axle as it was pulled across the desk would prevent it from winding up the string. It would just drag across the desk.

So without any explanation coming to explain why this works, here's one on why it wont work:

A vehicle gets a push from a 10 kt wind. Let's assume it has excellent bearings in the wheels and it accelerates to 9 kts. The reason it accelerates is wind resistance against the back of the vehicle. A propeller on the vehicle is moving along at 9 kts, and it is experiencing a 1 kt tail wind. The fact that the wind is moving at 10 kts along the ground is irrelevant. The propeller only gets 1 kt of relative airflow. The 1 kt spins the propeller to generate some electrical energy which is used to power the wheels - I am assuming this is what you're talking about because there's no other explanation offered.

The prop is not 100% efficient, neither is the generator, the wires carrying the current, the electric motors driving the wheels etc. The electric motors therefore cannot transfer to the wheels the same energy that the 1 kt of relative wind has. Let's say all this is very efficient and it adds 0.9 kts of speed to the vehicle. Now we're travelling at 9.9 - not 10 kts.

But, even in a frictionless world where propellers and electrical equipment are 100% efficient, you're only going to hit 10 kts. 10 kts is the maximum energy in this system. If somehow you exceeded 10 kts there would be a headwind on the vehicle. The prop would start turning in the opposite direction but more importantly, there is now more wind resistance which requires more energy. There is no explanation where this extra energy comes from. If it's from the propeller or wheel driven generators then there's going to be resistance produced which will slow the vehicle down.

This is truly a something for nothing situation.

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You haven't explained anything yet just made some claims.

I've explained that ice boats tacking downwind can be attached by a rod so that the whole "vehicle" goes directly downwind faster than the wind. Do you doubt they can be attached in such a manner? Do you doubt ice boats can tack downwind faster than the wind? Let me know where I need to add detail.

I've also offered a simple analogy with a yo-yo. But we can't go any further with that until you try it.

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I don't have any children's toys hanging around. Still, I don't see that working.

I know you don't. I said you wouldn't. You have to try it. Won't that be surprising if it works? You don't even have to bet $100K on it. For about $1.49 you can try it yourself.

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The torque from the yo-yo's axle as it was pulled across the desk would prevent it from winding up the string. It would just drag across the desk.

Though it's not necessarily intuitive, a rolling wheel doesn't roll about it's axle. It rolls about the contact point on the ground. This means the torque is actually in the right direction, but has some mechanical advantage to make the yo-yo go faster than my fingers which are pulling it.

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A vehicle gets a push from a 10 kt wind. Let's assume it has excellent bearings in the wheels and it accelerates to 9 kts. The reason it accelerates is wind resistance against the back of the vehicle. A propeller on the vehicle is moving along at 9 kts, and it is experiencing a 1 kt tail wind. The fact that the wind is moving at 10 kts along the ground is irrelevant.

Yes, it would be irrelevant if the prop were not geared to the wheels.

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The propeller only gets 1 kt of relative airflow.

Not true. Just as a sail on a sailboat experiences "apparent" wind, so does the prop on this cart. This only words due to the kinematic constraint provided by the wheels and transmission, just as the sail relies on the keel.

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The prop is not 100% efficient, neither is the generator, the wires carrying the current, the electric motors driving the wheels etc.

There is no motor, wires, or generator. The transmission is strictly mechanical. It's a simple timing belt from the prop shaft to the axle. And yes, it experiences real-world losses.

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But, even in a frictionless world where propellers and electrical equipment are 100% efficient, you're only going to hit 10 kts. 10 kts is the maximum energy in this system.

It's not a closed system. I'm taking energy out of the wind/ground interface. I don't think you'd doubt I could make such a cart that's powered by a stationary windmill with a long extension cord. All I have to do now is pick up that windmill, shuttle it to the front of the cart, and plant it back in the ground. I'll do this with two windmills, so one is always planted in the ground giving me all the power I need, while the other is being shuttled back to the front of the cart.

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If somehow you exceeded 10 kts there would be a headwind on the vehicle.

Yes there would.

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The prop would start turning in the opposite direction

Nope, it's kinematically constrained by the wheels and transmission.

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but more importantly, there is now more wind resistance which requires more energy.

Correct again, and I can get all the energy I need from the wind moving over the ground.

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There is no explanation where this extra energy comes from.

See above (and most of my posts above this one).

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This is truly a something for nothing situation.

It's truly not. It's not impossible. It's not perpetual motion. And it can and has been demonstrated.

I'm a little confused. Are you telling me you're certain it's impossible, or are you asking for better explanations and proof. If you're sure it's not possible you should ask to witness it in person, or take my $100K.

Ok, so a rod attached to an ice boat makes it go faster? Not much of an explanation there. Yes I doubt it because it makes no sense. I could put a rod on anything, not sure how it changes how fast it goes.

So a prop is geared to the wheels, the actual power being sent along the prop's shaft and down to the wheels is only being generated by 1 kt of wind. Yep, that prop is turning in relation to the speed of the wheels (since they're geared together) but there's only 1 kt of wind blowing against the prop- I bet the wheels actually turn the prop in this scenario rather than the prop turning the wheels. When the vehicle starts moving the airflow is blowing backwards over the prop, if it accelerates above the wind's speed as you claim they the airflow over the prop actually blows forwards. So the torque on the prop's shaft will actually reverse as it gets above wind speed.

There is only 1 kt of relative airflow. If a vehicle moves forward at 9 kts in a 10 kt wind - then do the math: 10 - 9 = 1. If the vehicle was going 10 kts forward in a 10 kt headwind, it would experience 20 kts of relative airflow.... pretty simple.

The keel on a sailboat keeps it going straight - it can't accelerate the wind or change the relative airflow going over a sail.

There's still no explanation being offered on how this works. For clarity, I am saying it is NOT possible. You still have to explain where the extra energy comes from to accelerate something above wind speed. Explaining that a rod is attached to an ice boat isn't quite the technical detail required.

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Originally posted by mithbust:
Ok, so a rod attached to an ice boat makes it go faster? Not much of an explanation there. Yes I doubt it because it makes no sense. I could put a rod on anything, not sure how it changes how fast it goes.

No, the rod doesn't affect how fast the ice-boat goes. It simply makes one vehicle out of two ice-boats since you aren't satisfied with a vehicle tacking downwind (nor should you be). With the rod we now have a vehicle that directly downwind - it just has two moving parts (the reciprocating ice-boats).

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So a prop is geared to the wheels, the actual power being sent along the prop's shaft and down to the wheels is only being generated by 1 kt of wind.

Again, not at all intuitive, but the prop is not turning the wheels, the wheels are turning the prop.

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I bet the wheels actually turn the prop in this scenario rather than the prop turning the wheels.

Yup!

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There is only 1 kt of relative airflow. If a vehicle moves forward at 9 kts in a 10 kt wind - then do the math: 10 - 9 = 1.

Again, this is true for a traditional boat going straight downwind. This vehicle takes advantage of apparent wind just as an ice-boat tacking downwind does.

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The keel on a sailboat keeps it going straight - it can't accelerate the wind or change the relative airflow going over a sail.

Ahhh - but it does. The wind felt by the sail (the "apparent wind" is the vector sum of the true wind and the boats speed. This can be significantly faster than the true wind. Everyone knows that a boat can go faster than teh wind on a beam reach, but not everyone is aware that a high performance boat can beat the wind downwind by tacking.

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For clarity, I am saying it is NOT possible.

Then to summarize - you're certain it can't be done, but you don't want to see it with your own eyes, and you don't want my $100K.

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You still have to explain where the extra energy comes from to accelerate something above wind speed.

As I've said in most of my posts, there is plenty of energy available from the ground/wind interface. Do you doubt a windmill could propel a cart faster than the wind with a long extension cord?

I am well aware that this sounds insane. That's what makes it interesting. If this were obvious or intuitive I wouldn't be debating it on this forum or trying to get the Mythbusters to do a segment on it.

End this now!...any scientific mind...aware of basic princilples...understands the "conservation of ENERGY." There is no FREE energy...aint gonna happen....End this before it turns into an airplane/treadmill thread...

Alrighty, I've had another thought. This one doesn't require a child's toy. It does require a bike without a rear deralleure. Here's what you do...

Grab the bottom of the chain midway between the front and rear sprockets. Pull the chain steadily foward (toward the front of the bike). Note that you are trying to pull the chain in the opposite direction that would normally propel the bike. But....

Note that the bike moves forward, and it does so faster than your hand on the chain is moving forward.

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Originally posted by macdaddy:
End this now!...any scientific mind...aware of basic princilples...understands the "conservation of ENERGY." There is no FREE energy...aint gonna happen....End this before it turns into an airplane/treadmill thread...

This is what we call "proof by absolute assertion".

You are aware the Mythbusters did a segment on the "airplane on a treadmill" which answered the naysayers quite effectively. Are you affraid of seeing the same thing here?

Why do you want to silence me? I would think you'd rather take my money.

good idea..see earlier conservation of energy thing....

It seems I'm the only one dumb enough to believe this is possible. I'm also the only one dumb enough to put my money where my mouth is.

Not dumb...there was an airline pilot (no-fly..very rere) who believed the airplane/tredmill thing...she hasn't been heard from ...since a naval aviator busted her b@lls. I'm sure she was smart...she just didn't take the time to think it through...

I'm sure that you are smart...but haven't thought this through....there are a lot of converts out there....

I have been converted...by others...often younger than me...when I listened...