So if the device travels faster than the wind while is deplenishes the wind and you measure the wind that's being deplenished. There are a lot of efforts that must be made to measure the device accurately.
At least I finally understand the concept behind the stupid thing.
Wikipedia had this to say: (feel free to answer any one of my questions) the ship is sailing the same speed of the wind so you throw a propeller in the water that runs a propeller in the air and you can gain speed.
The real question is how are all these DDWFTTW things related. On one hand you have a sailboat going around a cyclinder on the other hand you have a propeller blade that pulls a cart when given power by a treadmill, and finally you have a giant wind-powered vehicle on a salt bed. What is their connection?
If you can calculate that, as they have, then that's valuable and thats what physics is for, calculating results. It shouldn't claim to be able to accurately predict unknown things that are going on. It is used to do so and has been accuracte in the past, but it has also been wrong.
That is what I most question about physics. I think the predictions are valuable and all and we need good models to work from.
Now that we've gotten that out of the way, explain how the wind stays in reserve as you constantly have to use the same wind over and over again as you travel around the cylinder.
No force is created by the propeller, it is only a constantly tacking sail.
@planetofthescums - you dear sir need to use google an find one of them threads with thousands of different ways of explaining the phenomenon. You say calculations are drivel - I a not bothering to check what you refer to. It's rather simple phenomenon and at the core angular velocities or laminar floes etc are not relevant
@axelerat3d You are putting words into my mouth, saying that I am saying the calculations are drivel etc. I am no disputing you I am simply trying to understand and you are acting like I am a professor at your college trying to debate with you. This is not a debate, I am not arguing with you. You simply don't explain it properly and attack anyone who doesn't understand. Its nobody's fault but your own if you get upset when people don't understand you!
@axelerat3d I read the original idea which came from sailing around a cylinder of ocean.
A wind blows across a cylinder of water, parallel to the central axis. You are on board a sailboat, sails slanted to the wind, going about with speeds exceeding the wind, naturally.
The direction of the boat is not directly downwind, but on a cylindrical ocean, there is a point on the central axis of the ocean directly below the hull of the boat.
The question is, does this point move faster than the wind?
Check the other linked vid. the wind is not parallel to the cylinder but in the direction of the cylinder. The boat corkscrews around said cylinder so it experiences apparent wind (felt on boat) higher than the wind speed - thus it can create lift beyond reaching the wind speed.
watch?v=UGRFb8yNtBo
Its all about leverage. A small breaking force affecting big speed difference (ground/cart) can be turned into bigger force acting in smaller speed difference (propeller/air)
@axelerat3d More to the point, if you could start one boat going with sails perpendicular to the wind and another slanted, does one travel faster or slower than the other down the cylinder?
The answer is obvious when you are tacking upwind; it seems less so when you are tacking downwind.
I think the question most people have is, is this even worth getting worked up over, since sailors have been using this "tacking" to get around since before the dark ages?
I am sorry if I come off lazy for not reading that stuff which is available, but I find pysics difficult to comprehend, and I am not sure I buy into all of it. Maybe I am wrong for it but I mean... come on, mechanical physics comes with a disclaimer saying that it really doesn't work the way it is presented.
These diagrams and math equations "represent" what is going on. There are many ways to write formulas that work out to the answer.
@axelerat3d The uh, concept behind it, is interesting and not immediately apparent.
I just sort of threw myself into this heated argument because I can see it from both sides and it appears a lot is getting lost from misunderstandings more than any real debate.
Just be careful when describing it to people. Some ways of putting things are going to confuse people, people without any background with angular velocity, for example. Knowing the end of a maze is not the same as going through it.
@axelerat3d Think of the maze as all the ways you can look at the problem without finding an answer, friction, inertia, conservation of energy, these are all trademarks of good thinking.
I can go somewhere else to really understand the explanation. Its hard to try and explain all this to you without really understanding how the thing works, but that's alright.
You ahve reality on your side, but you could use a couple of steps for average people to get up to sharing your understanding.
and I have actually taken the time to make an animation explaining it all...
You have this weird idea that I have some ind of duty to do the work for folks to understand. yet you admit that you don't bother reading but still want easier explanations. Come on.
Its not the physics fault if you don't get it. And I am sure you are capable of getting it if you bothered. If you choose not to it ain't my bad.
@axelerat3d You should enjoy explaining what you know to people. I only say so if you are getting frustrated. How better to spend time than educating?
@axelerat3d This isn't even worth getting worked up over and the only people you are going to get interested in this idea are people like me who don't understand it. It is tacking wind, I learned about this sometime over 20 years ago playing a video game called Pirates!. The entire industry of this subject is in the misunderstanding poor explanations and wild claims of physicists being stumped by a very simple problem, and as suspected this fan thing was already done before, as I remembered.
Nobody is claiming that it is anything more special than it is. Its a brain teaser. If you think our explanations are bad why don't you summarize how you understood it. I am all ears for more intuitive ways to explain it. I have tried zillion and different people seem to get the light bulb going off from different clues.
it is counter intuitive - that is why it is a mind teaser. The creators of the cart in the video have credited several predecessors of the idea.
@axelerat3d How it initially moves forward the same as how it finishes moving forward. You have some choices on how you describe that but it must be able to work throughout the entire process.
The way it moves at 0.01 mph is the same as how it moves at 38 mph. Is the prop pushing the wind, is the wind pushing the cart, are the wheels driving the propeller... you have to be very careful how you describe what the cart is doing and I think, if indeed problems persist, this is where they lay.
You should enjoy explaining what you know to people, perhaps your explanation needs improvement. I only say so if you are getting frustrated. You can imagine that all the people in the world share a big brain and it does not develop easily., but how better to spend time than educating yourself?
Like the wind moves together like a wall to create this effect, when we share knowledge greater things can happen than one mind alone could produce.
Here's a nice explanation that requires no physics if you believe in typical sailing. Sail boats get downwind faster than the wind by tacking (zig zaging) but they can't beat the wind if the hull and direction point downwind. If you could tack 10x/sec you might claim to be going directly downwind, but it would be a noisy and bumpy ride. This machine makes it smooth. The top of this propeller is like tacking left and the bottom is like tacking right at the same time, for a comfortable ride.
If you look at the direction the prop starts spinning, if there is a tail wind, it should be spinning the opposite direction. Why did it weigh 450 lb? It's the weight of the batteries and motor!
Search youtube for "DDWFTTW - Prop or Turbine". It shows a bare model self starting in a tailwind with the propeller spinning just like here. Switch on your brain to understand why (Don't forget to recharge the batteries)
Yes, I wrote an article that appeared in Make magazine on-line, and the current print issue includes an article describing how to build your own working small-scale model.
This vehicle is not powered by the wind at all. Think of it at zero wind, and then accelerating faster than the wind. That means that I can go outside with no wind, with this car, and it should accelerate by itself. In fact, let's just put this turbine design in a big box, and let it spin faster and faster and generate electricity for free. If so, congratulations for finding a loophole in the second law of thermodynamics. I still am skeptical until I see it in real life or build it myself.
@sfomail "Think of it at zero wind," nothing would happen " I still am skeptical until I see it in real life or build it myself." That's because you don't understand you can extract energy for the wind even going down wind. The same way ice yachts can sail down wind jibbing much faster than the wind speed.
@sfomail You can build one of these for yourself. spork33 has a series of three videos that show you how to build a small scale version of this. These are the same small carts that were tested on treadmills. You should be able to do this for about $40.00 in parts. And it runs off of the difference between the speed of the air and the speed of the ground. That difference exists regardless of the cart's speed.
Is the lateral movement of the propellor relative to the wind direction essential? I'm thinking perhaps it corresponds to the effect of a fixed sail vehicle traveling at an angle to the direction of the wind, which can greatly exceed wind speed (up to 4-5x !?!).
A fixed-sail vehicle that periodically accelerated at an angle to the wind to faster than wind speed, then coasted in a before-the-wind heading, could travel before the wind faster the wind indefinitely. Similar to propellor?
Yes of course the lateral movement of the propeller blades is essential. The blades are moving at an angle to the wind, while the car moves directly downwind. See the videos by axelerat3d and eyytee for the analogy to sail craft.
@minkymott About 28 mph in a 10 mph wind for the record run. They had to even higher speeds. They have 3.5 times the speed of the wind, but they were not close enough, or have enough data to use it for a valid record claim. If you search for BUFC blow up run you can see it running at 45 mph in a 15 mph wind. The BUFC was the unfinished Blackbird without all of the aerodynamics. Detractors called it a Big Ugly F***ing Cart and the acronym was adopted by spork and JB.
Just saw this. I also see some rancor in the comments.
Anyway, does it work by accumulating energy in the car and then dumping that to the wheels for a temporary burst of speed? Or, is the assertion that the car could travel indefinitely at 50 miles per hour with a 20 mile per hour tail wind coming from directly behind?
I know a sailboat can exceed windspeed at right angle to the wind, and that windmill-powered vehicles can travel straight into the wind. Haven't seen this before though.
No it doesn't use stored energy for propulsion. This would be against the rules of NALSA-records. Note that no part of the vehicle slows down, when the vehicle accelerates, so part releases stored energy. With endless space and constant wind it can go at a constant speed greater than wind speed indefinitely.
There is no violation of the laws of physics, it works just as a hub gear on a bicycle. The force that the wind exerts on the propeller is greater than the force of aerodynamic drag holding the car back. Just like a bike wheel can rotate faster than the pedals, but with less force. It's a gearing up situation, greater velocity but with less force. The ground is an anchor point, a fulcrum for the lever.
Love it. It made my mind pop but it makes sense. The "virtual" wind speed at the propeller is actually the speed of the vehicle plus the speed of the wind, not just the wind speed, so there's extra energy to be used? Fantastic.
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Um...... "hey guys, heres a though! Lets build a machine that can go downwind faster than the wind and spend a shit load of money on something useless!!!!"
@Pyr0Maniac01 "Yeah I don't get the purpose of it." And thus you join that peculiar group of people at the first balloon flight, first public demonstration of the Wright flyer, the first demonstration of a steam propelled ship, Columbus's return, etc etc etc, who say "It's all useless" Never so happy as when you are bagging someone who has made an effort to push a boundaries. Get a life for gods sake
@fizzguts You contradict yourself. Do you just cruise you tube all day long and troll the comment sections. lets look at your comment history ,Oh shit you do! 1 hr ago negative comment 7hrs ago negative comment 8 hrs ago negative comment 9hrs 10 hrs Wow all the way back to 2 days and not a single positive or constructive comment. At 59 years old I think you are the one that needs to get a life, or even better, GET A FUCKING JOB!
You don't have to have a degree in maths or use any maths at all to see how this works. It's really just common sense. The craft doesn't care if the ground is moving or the air is moving. (How could it know?) It's the relative movement that counts. So it can make progress over the ground, driven by the wind, or it can make progress through the air driven by the ground. However, this kind of "upsidedown" thinking seems beyond most people.
This must be a hoax. Consider what happens if the vehicle reaches the exact speed of the wind. At that point the propeller will be in exactly the same situation as if there was no wind at all. What these people are presenting is that this device could start in zero wind and accelerate to a considerable speed. Come on! Perpetual motion machines do not work .
If there is no hidden energy source in the device, such as a battery/motor then it works by storing up energy first like a friction toy car
It is not a hoax. The record has been verified. Google "nalsa downwind"
At "windspeeed" is NOT the same situation as with "no wind": The ground speed is different.
Of course it stores energy, when it accelerates. But it cannot use that energy to accelerate or even keep a constant speed, because it cannot slow down any parts, without slowing down the entire vehicle.
this make me thinks an eternal-motor is near. Some years ago I formulated an idea mixing wind;sun;thermal;magnetic and; vibration. to formulate just for fun the possibility of an eternal-motor. I'm brazil(sorry for my english), but if your brilhant mind interested on my ideias, I live for science.
Lets get this thing on the ice this winter. Come to Madison WI this winter and we can help you with the runner arrangement and see it go on a frictionless surface. Check out our web site at iceboat.org
bad idea. this one needs friction to work. your iceboats also need friction in the lateral direction to go really fast. with no friction at all, you would just drift along with the airmass.
yall are all retards. I am not even going to bother explaining this to you bc you will rule it as incorrect and then go about making up some more bullshit on how it works.
:O, antes de ver este vídeo creía que sería posible (con otros modelos)... pero ahora este vídeo muestra algo que me hace cambiar de opinión. miren en 1:15 el viento viene desde atrás del vehículo, pero las aspas giran en sentido contrario al viento (deberían girar al otro sentido o por ultimo frenarse, pero va en una aceleración constante)... según yo (un ignorante cualquiera) debería recién adquirir su propulsión en 1:41 ¿no será que tiene un motor auxiliar?
How could a kite or sail ever drive a ddwfttw cart? That makes no sense. They obviously will max out at (actually somewhat under) wind speed when going directly downwind.
@EebstertheGreat You can go faster than the wind by cutting across the wind; then turn downwind. At that moment you would be travelling downwind faster than the wind, before slowing down.
*sigh*. Look the wind pushes on the blades which pushes the cart forward and starts to turn the tires which starts turning the propeller against the wind. It's obvious in the video. It's possible because the cart is extremely light and the wind is strong. This continues until the cart is going as fast as the wind at which point the propeller is going fast enough to push the cart to the next stage. Just google dwfttw and read the blogspot.
So this vehicle is going faster because it is using a transmission to "convert" the radial speed of the windmill into faster radial spin of the wheels?
no as explained earlier, the wheels spin the propeller that pushes the air backwards - against the wind. at low speed the prop is acting as simple wind catcher not much unlike a parachute or anything with drag. As the vehicle accelerates the prop starts acting.
@pebre79 The speed of rotation is called "angular velocity".
(Radial spin and radial speed are each different and separate terms.)
Looking at a bicycle, the speed of both sprockets, the one driving the chain and the other driving the wheel, are both equal; along with the chain's speed.
Without understanding the correct terminology it gets confusing.
The angular velocity however changes with each radius.
@pebre79 Notice, however, the sprocket driving the wheel and the wheel itself have the same angular velocity and two different speeds.
The same is true for the pedals and the sprocket driving the chain.
There is some sort of conversion although at this point I do not know what it is, it is completely related by radii. There are many possible combinations; the wheels may actually be driving the fan blades.
@DanFrederiksen Until the point at which the tailwind becomes a headwind, around 1:40, at that point it becomes like a windmill with the prop driving the wheels rather than the wheels driving the prop. It creates it's own feedback loop. Very clever indeed.
True the propeller never changes direction, but once the tailwind has become a headwind it is no longer pushing the air but is being pushed BY the air.
@ZazuYen "True the propeller never changes direction, but once the tailwind has become a headwind it is no longer pushing the air but is being pushed BY the air."
.
The propeller is ALWAYS pushing the air backwards, against the direction of the TRUE wind. Wind energy ALWAYS comes from reducing the TRUE wind.
@axelerat3d That doesn't make any sense. If the wheels are geared to drive the prop, where's the initial starting force coming from? Magic? Even if true, it seems rather pointless - the reason it can go faster than the wind is because of the gear reduction ratio between the prop and the wheels; it has nothing to do with any weird wheel-prop-feedback nonsense.
maybe my explanation wasn't the greatest BUT the prop is blowing backwards. Not acting as a "windmill". What gives the initial start? the wind of course. If the propeller could spin freely the wind would make it spin the other way.
@axelerat3d No, that's stupid, and completely wrong. If the prop were acting as a pusher, you'd need an engine to spin it. You don't get to use the wind to spin a prop, and then magically have the same prop push air backwards. You obviously have no clue what you're talking about.
Really - why don't you go and read the creators blog where it is very clearly explained. Also you see it very clearly on several of the slow start of the cart that it is indeed a pusher. What spins it? the wheels. Not vice versa.
I see you pulled your comments on me making shit up and having a losing strategy. and having no pride... Maybe you should concentrate less on insults and try to follow what others try to explain - even if you don't agree you shouldn't shut down before you give it some thought. No need for insults. AND now the exact quote from one of the co-creators:
""The downwind car is designed with a propeller that pushes it along like an aircraft's propeller does, it is not a windmill or a turbine. Instead of an engine to turn the propeller, the propeller is geared to the wheels of the car, so that as the car moves forward, the propeller spins in such a way that the car will speed up if there is energy available from a tailwind."
@axelerat3d Yeah, that explanation is garbage. They're describing a perpetual motion machine. The wind pushes the car, which spins the wheels, which spin the prop, which pushes the car, which spins the wheels, ad-infinitum. Sheer nonsense. They either REALLY suck at explaining what they've done, or they have no idea how their own vehicle actually works.
well it does work. And it ain't perpetual motion. P=FV so when traveling downwind your wheels relative speed to the ground is higher than the props speed in relation to the wind.
So test that idea with different numbers FV[wheel-ground]>F[air-prop]
You will see that with 10N braking force you can create 20N pushing force. Its just like a transmission in purely mechanical system - you trade speed to torque - or in this case thrust.
@axelerat3d I'm not questioning whether it works. We know that you can go faster than the wind. The question is HOW does it work, and your repetition of their formulas (or your incorrect usage of the term "pusher prop") does nothing to explain that.
At first, the prop probably works as little more than a sail. With variable-pitch blades it could also work directly on the wheels. Once it gets up to zero relative velocity, that's where it gets interesting, and their explanation makes no sense.
if the cart is going 9m/s in the direction of the wind of 10m/s and the wheels are "braking" with force 20N how much thurst in Newtons can the prop create from that force if we exclude all losses?
Answer 9m/s*20N= 180w and 180w can create thrust of 180N as the apparent speed for the prop is only 1m/s. F=P/V =180w/1m/s=180N
Of course in reality prop is very inefficient in certain conditions etc. so the situation is not as good but principle is correct.
@axelerat3d If the wheels are braking with a force of 20N, you'll be losing power, not creating more. Multiplying numbers together randomly makes you sound all scientific to the layman, but it's still meaningless drivel. Look I can do it too:
If the flux capacitor generates 33 million newtons, and the car is moving at 80 miles per hour, how much power can the wheels create? P=V*F=1.2 gigawatts! Therefore time travel IS possible!
@axelerat3d Ah, yes, the final retort of every incompetent: "It's not my fault that I can't explain it, you just don't want to understand!"
Actually, for the record, I've found some forums that do a much better job of explaining the process. I need to crunch some numbers, but the concept seems valid. I suppose I should thank you for trying, at least. I admire your tenacity, if not your communication skills :)
axelerat3d's explanations and calculations are fine. It is a propeller, powered by the shaft, creating thrust, even in still air or apparent headwind. You don't need an engine for that, just the right gearing and a velocity difference between the two media. There are different ways to explain it. Just because you don't get one of them, doesn't mean the explanation is wrong.
Do the math, instead of making claims based solely on your gut feeling and everyday experience.
@eyytee It's got nothing to do with "gut feeling and everyday experience". The entire problem is the inability of these people to explain what it is they're doing. Talking about a propeller pushing wheels and wheels spinning the propeller is guaranteed to get them dismissed as a bunch of cranks. If they had any clue how to communicate their ideas to others, they'd have been taken more seriously from the beginning instead of being ridiculed by damn near everyone.
But "propeller pushing wheels and wheels spinning the propeller" is a correct explanation. The only missing bit is, that the propeller is not doing the pushing alone, but is supported by the movement of the air mass.
It is a brainteaser. You are supposed to find out yourself how it works. Or at least learn enough physics to understand the explanation, not complain about the explanations. They were dismissed as cranks only by people who "know some physics", but cannot do the math.
This comment has received too many negative votesshow
@eyytee lol. No, they were dismissed as cranks by EVERYONE. The only people who took them seriously were the woo-purveyers (some of whom have commented here) who believe all sorts of stupid shit.
It's cute how you're trying to make excuses now, but the reality is that science depends on clear explanations and reproducible experiments. If you can't explain what you've done, you shouldn't expect to be taken seriously.
what a fool. Check eyytee's videos and mine. We have spent some time explaining this - not because we are in anyway involved with the cart but because we find it an interesting dilemma. You act like we have some kind of responsibility to to make YOU understand. It ain't so.
Science is not based on the idea that everyone should get it. Not at all. The creators of the cart understand very well how it works and now they have proved that it does. You would get it too if you tried.
You confuse "majority" with "everyone". And I have no need to give excuses, for your failure to understand something. This cart works fine without you understanding it.
@eyytee You apparently do feel a need to give excuses for your inability to communicate. Which is as it should be. It would be much more efficient to accept that you are an idiot when it comes to explaining / teaching, instead of repeatedly whining about it not being your fault.
You are trying to excuse it, by the silly claim that everyone is just as ignorant as you are.
It would be much more efficient to accept that you are an idiot when it comes to understanding physics, instead of repeatedly whining about it not being your fault.
LOL, Yeah, you totally "get it" now. Better than the guys who build it, because their explanations are wrong according to you. But a guy like you, who doesn't even understand P = F * v and thinks it just "multiplying random numbers", surely has a much better explanation.
So let's hear it! Please explain to us how it works.
@eyytee The minority may not include the cranks and illigetimate critics. It would have to be credible scientists who think the explanation is worth a second look.
I have an inkling that machines travelling downwind faster than the wind are nothing new.
@eyytee You must show the direction of the force and the magnitude of the force for your explanation to be of any use to us. Simply saying the air pushes the propeller which pushes the wheel which turns and pushes the air may be "correct", but it makes no difference because it is not detailed enough of an explanation.
Saying it can move in STILL AIR makes your explanation of how the propeller works completely false, the only way you can do this is by having an ENGINE (treadmill).
- For force vectors check my video: "Directly Down & Up Wind Faster than the Wind".
- By "still air" I meant zero relative wind, not zero true wind. This cart doesn't work without true wind. But its propeller still works in zero relative wind and slows down the true wind.
@eyytee From the perspective of standing on front of the cart looking rearward, the air was initially moving toward your face. At a certain point the the air stops and then is blowing against your back.
My explanation is that the prop did not cause turbulence while it slowly built up speed, the air was slowing down, and blowing behind it (passing eachother). This allowed the prop to build up inertia.
At a key point the propeller causes turbulence and then pulls air forward. (Watch your fingers.)
@eyytee This is why your explanation is hard to digest, because you said the propeller pushes the wind and the wind pushes the cart. This not true from the same perspective or the same time frame.
I haven't done any mechanics, but I imagine this is what is important. I also imagine this is what is going on.
"If the wheels are braking with a force of 20N, you'll be losing power,"
Yes you will be braking with 20 N but as in the example you can push with 180N you have excess of force -> acceleration.
If you took over 30 seconds to consider the fact that the wheels and the prop have interaction with different speed mediums you would get that 20N can easily be geared to be much more in the other medium. Equal power can be geared to different forces.
Richard, are you insprired to start a project for a DDW specific and speed record yet? Forget the multiple of wind speed, just design for higher winds and rip up that lake bed!
All it takes is someone telling spork & JB, that it is impossible to break Richard's record with a DDW-vechicle, and these guys will build one and do it.
You sure have a point there. With their way of covering their progress, it should be quite a ride, even for those following the project on the internet.
Cart goes in the wind, you go in the cart, propeller is in the wind...
Does he put the brakes on the end, does the wind die, what happens?
planetofthescums 2 months ago
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planetofthescums 2 months ago
So if the device travels faster than the wind while is deplenishes the wind and you measure the wind that's being deplenished. There are a lot of efforts that must be made to measure the device accurately.
At least I finally understand the concept behind the stupid thing.
Wikipedia had this to say: (feel free to answer any one of my questions) the ship is sailing the same speed of the wind so you throw a propeller in the water that runs a propeller in the air and you can gain speed.
planetofthescums 2 months ago
This has been flagged as spam show
The real question is how are all these DDWFTTW things related. On one hand you have a sailboat going around a cyclinder on the other hand you have a propeller blade that pulls a cart when given power by a treadmill, and finally you have a giant wind-powered vehicle on a salt bed. What is their connection?
planetofthescums 2 months ago
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planetofthescums 2 months ago
It uses the wind, moves faster than the wind, wind loses energy, then it stops moving faster than the wind.
planetofthescums 2 months ago
If you can calculate that, as they have, then that's valuable and thats what physics is for, calculating results. It shouldn't claim to be able to accurately predict unknown things that are going on. It is used to do so and has been accuracte in the past, but it has also been wrong.
That is what I most question about physics. I think the predictions are valuable and all and we need good models to work from.
planetofthescums 2 months ago
...and the gearing and blade angle would have to be set to work optimally for certain wind speeds.
planetofthescums 2 months ago
Now that we've gotten that out of the way, explain how the wind stays in reserve as you constantly have to use the same wind over and over again as you travel around the cylinder.
No force is created by the propeller, it is only a constantly tacking sail.
Tell me where I am wrong.
planetofthescums 2 months ago
@planetofthescums - you dear sir need to use google an find one of them threads with thousands of different ways of explaining the phenomenon. You say calculations are drivel - I a not bothering to check what you refer to. It's rather simple phenomenon and at the core angular velocities or laminar floes etc are not relevant
axelerat3d 2 months ago
@axelerat3d You are putting words into my mouth, saying that I am saying the calculations are drivel etc. I am no disputing you I am simply trying to understand and you are acting like I am a professor at your college trying to debate with you. This is not a debate, I am not arguing with you. You simply don't explain it properly and attack anyone who doesn't understand. Its nobody's fault but your own if you get upset when people don't understand you!
Math is drivel <- philosophical viewpoint
planetofthescums 2 months ago
@planetofthescums
Sorry my bad. Understand that related to this topic many skeptics approach with blatant attacks. Thus my reaction erred on the side of defensive.
In trying to explain the phenomenon a few questions:
Do you know/agree that sail cart can travel downwind faster than the wind (directly down wind made travel) ?
Do you understand why that is?
If you do then check this:
watch?v=UGRFb8yNtBo
basically propeller blade is an airfoil continuously at an angle to the wind
axelerat3d 2 months ago
@axelerat3d
And very 1st thing you have to understand - the wheels spin the prop. It is NOT a turbine spinning the wheels.
Now the ground and air could be any medium. The energy comes from the difference of the 2 mediums.
Rather than thinking downhill you could think 'upground' for example.
If you think of the vehicle at at exact speed of the wind. The ground is passing by at the speed of wind but the experienced apparent wind is zero.
axelerat3d 2 months ago
@axelerat3d I read the original idea which came from sailing around a cylinder of ocean.
A wind blows across a cylinder of water, parallel to the central axis. You are on board a sailboat, sails slanted to the wind, going about with speeds exceeding the wind, naturally.
The direction of the boat is not directly downwind, but on a cylindrical ocean, there is a point on the central axis of the ocean directly below the hull of the boat.
The question is, does this point move faster than the wind?
planetofthescums 2 months ago
@planetofthescums
Check the other linked vid. the wind is not parallel to the cylinder but in the direction of the cylinder. The boat corkscrews around said cylinder so it experiences apparent wind (felt on boat) higher than the wind speed - thus it can create lift beyond reaching the wind speed.
watch?v=UGRFb8yNtBo
Its all about leverage. A small breaking force affecting big speed difference (ground/cart) can be turned into bigger force acting in smaller speed difference (propeller/air)
axelerat3d 2 months ago
@axelerat3d I got the idea across to you without needing to say anything about lift. Suffice to say the "boat speed" is faster than the wind!
"Thus it can create lift beyond reaching the wind speed?" What does that even mean, is it even English?
You didn't think I knew the direction the wind was blowing, you surely didn't expect me to understand this sentence?!?!
Then you bring up leverage, breaking force, and so scientific terms like big speed, small b.f., bigger force, and smaller speed? WTF
planetofthescums 2 months ago
@axelerat3d More to the point, if you could start one boat going with sails perpendicular to the wind and another slanted, does one travel faster or slower than the other down the cylinder?
The answer is obvious when you are tacking upwind; it seems less so when you are tacking downwind.
I think the question most people have is, is this even worth getting worked up over, since sailors have been using this "tacking" to get around since before the dark ages?
planetofthescums 2 months ago
@axelerat3d Another question is how does such a simpe idea get convoluted into relativity and speeds of different mediums?
The wind pushes the blades which push the cart, turns wheels, and gets the blades to tacking in this cylindrical fashion.
"Sails" do not push wind backwards. The forward motion in the cart comes from forward motion of the wind, not rearward motion of the wind.
Or is it a "pusher prop" that forces the air to change direction?
planetofthescums 2 months ago
@axelerat3d I don't think its simple at all.
I am sorry if I come off lazy for not reading that stuff which is available, but I find pysics difficult to comprehend, and I am not sure I buy into all of it. Maybe I am wrong for it but I mean... come on, mechanical physics comes with a disclaimer saying that it really doesn't work the way it is presented.
These diagrams and math equations "represent" what is going on. There are many ways to write formulas that work out to the answer.
planetofthescums 2 months ago
@axelerat3d The uh, concept behind it, is interesting and not immediately apparent.
I just sort of threw myself into this heated argument because I can see it from both sides and it appears a lot is getting lost from misunderstandings more than any real debate.
Just be careful when describing it to people. Some ways of putting things are going to confuse people, people without any background with angular velocity, for example. Knowing the end of a maze is not the same as going through it.
planetofthescums 2 months ago
@axelerat3d Think of the maze as all the ways you can look at the problem without finding an answer, friction, inertia, conservation of energy, these are all trademarks of good thinking.
I can go somewhere else to really understand the explanation. Its hard to try and explain all this to you without really understanding how the thing works, but that's alright.
You ahve reality on your side, but you could use a couple of steps for average people to get up to sharing your understanding.
planetofthescums 2 months ago
@planetofthescums
and I have actually taken the time to make an animation explaining it all...
You have this weird idea that I have some ind of duty to do the work for folks to understand. yet you admit that you don't bother reading but still want easier explanations. Come on.
Its not the physics fault if you don't get it. And I am sure you are capable of getting it if you bothered. If you choose not to it ain't my bad.
axelerat3d 2 months ago
@axelerat3d You should enjoy explaining what you know to people. I only say so if you are getting frustrated. How better to spend time than educating?
planetofthescums 2 months ago
@axelerat3d This isn't even worth getting worked up over and the only people you are going to get interested in this idea are people like me who don't understand it. It is tacking wind, I learned about this sometime over 20 years ago playing a video game called Pirates!. The entire industry of this subject is in the misunderstanding poor explanations and wild claims of physicists being stumped by a very simple problem, and as suspected this fan thing was already done before, as I remembered.
planetofthescums 2 months ago
@planetofthescums
Nobody is claiming that it is anything more special than it is. Its a brain teaser. If you think our explanations are bad why don't you summarize how you understood it. I am all ears for more intuitive ways to explain it. I have tried zillion and different people seem to get the light bulb going off from different clues.
it is counter intuitive - that is why it is a mind teaser. The creators of the cart in the video have credited several predecessors of the idea.
axelerat3d 2 months ago
@axelerat3d I get you understand the basic concept of the cart. People, like myself, who don't understand the cart make confusing statements.
The other thing is, I don't understand the wind, I don't understand gears, and so on.
The best way to explain it is physically how the parts are constructed. That should be the basic starting point that would negate a lot of confusion.
I am just curious about the balancing act of the cart higher ends and that requires a larger background of information.
planetofthescums 2 months ago
@axelerat3d I still don't see the point of it "tacking" that seems unecessary.
Just ignore friction and other things if people don't bring it up themselves; most people tend to ignore that stuff without mention.
Then, what exactly it claims to do, it claims to take energy from a volume of wind and use it to accelerate a cart to a high rate of speed.
So you have to explain next why this won't work with light particles reflecting on a solar propeller because nothing exceeds light speed. (jk)
planetofthescums 2 months ago
@axelerat3d How it initially moves forward the same as how it finishes moving forward. You have some choices on how you describe that but it must be able to work throughout the entire process.
The way it moves at 0.01 mph is the same as how it moves at 38 mph. Is the prop pushing the wind, is the wind pushing the cart, are the wheels driving the propeller... you have to be very careful how you describe what the cart is doing and I think, if indeed problems persist, this is where they lay.
planetofthescums 2 months ago
You should enjoy explaining what you know to people, perhaps your explanation needs improvement. I only say so if you are getting frustrated. You can imagine that all the people in the world share a big brain and it does not develop easily., but how better to spend time than educating yourself?
Like the wind moves together like a wall to create this effect, when we share knowledge greater things can happen than one mind alone could produce.
Think of it like squeezing a water bottle.
planetofthescums 3 months ago
At 1:55 , hiball. She is really going w the relative speed of the wind
kae4466 4 months ago
Here's a nice explanation that requires no physics if you believe in typical sailing. Sail boats get downwind faster than the wind by tacking (zig zaging) but they can't beat the wind if the hull and direction point downwind. If you could tack 10x/sec you might claim to be going directly downwind, but it would be a noisy and bumpy ride. This machine makes it smooth. The top of this propeller is like tacking left and the bottom is like tacking right at the same time, for a comfortable ride.
grumpystiltskin 9 months ago
If you look at the direction the prop starts spinning, if there is a tail wind, it should be spinning the opposite direction. Why did it weigh 450 lb? It's the weight of the batteries and motor!
paulshem1 9 months ago
@paulshem1
Search youtube for "DDWFTTW - Prop or Turbine". It shows a bare model self starting in a tailwind with the propeller spinning just like here. Switch on your brain to understand why (Don't forget to recharge the batteries)
piratewoodleg 9 months ago
Great job . Way to go
scoobydog411 9 months ago
@ericgiffly
Yes, I wrote an article that appeared in Make magazine on-line, and the current print issue includes an article describing how to build your own working small-scale model.
spork33 9 months ago
This vehicle is not powered by the wind at all. Think of it at zero wind, and then accelerating faster than the wind. That means that I can go outside with no wind, with this car, and it should accelerate by itself. In fact, let's just put this turbine design in a big box, and let it spin faster and faster and generate electricity for free. If so, congratulations for finding a loophole in the second law of thermodynamics. I still am skeptical until I see it in real life or build it myself.
sfomail 10 months ago
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@sfomail "Think of it at zero wind," nothing would happen " I still am skeptical until I see it in real life or build it myself." That's because you don't understand you can extract energy for the wind even going down wind. The same way ice yachts can sail down wind jibbing much faster than the wind speed.
fizzguts 10 months ago
@sfomail You can build one of these for yourself. spork33 has a series of three videos that show you how to build a small scale version of this. These are the same small carts that were tested on treadmills. You should be able to do this for about $40.00 in parts. And it runs off of the difference between the speed of the air and the speed of the ground. That difference exists regardless of the cart's speed.
subductionzone 9 months ago
Was this video taken at the Black Rock Desert in Nevada ?
Sure looks familiar.
cliffsplace 11 months ago
@cliffsplace ...El Mirage, my bad.
cliffsplace 11 months ago
If I remember correctly, the raw data posted for this vehicle's speed vs. wind speed did not support their claims.
snorman1911 11 months ago
@snorman1911
The North American Land Sailing Association has ratified their record of 2.8x windspeed directly downwind. Google "nalsa downwind"
piratewoodleg 11 months ago
@snorman1911
"If I remember correctly,"
You didn't
fizzguts 10 months ago
Way to go!!! Great job in solving the "faster than wind" sailing debate Cavallaro!!!
ithillien99 11 months ago
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read this on WIRED. really amazing.
rivengle 11 months ago
rather use a vertical axis windmill, much better to harvest wind from all directions
Guds777 11 months ago
Kinda makes me think of a supercharger, not like it IS one, just the self propelling thingy. Feel free to attempt to educate me :P
lolffels 1 year ago
wait wait wait, from the direction of the little windmill at the beginning, is the wind flowing from the back?
seanwfd 1 year ago
@seanwfd
Video description: "This is a vehicle built to travel dead DOWNWIND, faster than the wind itself!"
piratewoodleg 1 year ago
Is the lateral movement of the propellor relative to the wind direction essential? I'm thinking perhaps it corresponds to the effect of a fixed sail vehicle traveling at an angle to the direction of the wind, which can greatly exceed wind speed (up to 4-5x !?!).
A fixed-sail vehicle that periodically accelerated at an angle to the wind to faster than wind speed, then coasted in a before-the-wind heading, could travel before the wind faster the wind indefinitely. Similar to propellor?
voltamp 1 year ago
@voltamp
Yes of course the lateral movement of the propeller blades is essential. The blades are moving at an angle to the wind, while the car moves directly downwind. See the videos by axelerat3d and eyytee for the analogy to sail craft.
piratewoodleg 1 year ago
It Is Impressive no matter what.
zebradun6 1 year ago
Maybe I missed it, but how fast was it going?
minkymott 1 year ago
@minkymott About 28 mph in a 10 mph wind for the record run. They had to even higher speeds. They have 3.5 times the speed of the wind, but they were not close enough, or have enough data to use it for a valid record claim. If you search for BUFC blow up run you can see it running at 45 mph in a 15 mph wind. The BUFC was the unfinished Blackbird without all of the aerodynamics. Detractors called it a Big Ugly F***ing Cart and the acronym was adopted by spork and JB.
subductionzone 1 year ago
...or by converting the windmill to a propellor and dumping energy into the propellor for a temporary burst of speed?
voltamp 1 year ago
Just saw this. I also see some rancor in the comments.
Anyway, does it work by accumulating energy in the car and then dumping that to the wheels for a temporary burst of speed? Or, is the assertion that the car could travel indefinitely at 50 miles per hour with a 20 mile per hour tail wind coming from directly behind?
I know a sailboat can exceed windspeed at right angle to the wind, and that windmill-powered vehicles can travel straight into the wind. Haven't seen this before though.
voltamp 1 year ago
@voltamp
No it doesn't use stored energy for propulsion. This would be against the rules of NALSA-records. Note that no part of the vehicle slows down, when the vehicle accelerates, so part releases stored energy. With endless space and constant wind it can go at a constant speed greater than wind speed indefinitely.
piratewoodleg 1 year ago
Sorry, I meant: "NO part releases stored energy"
piratewoodleg 1 year ago
There is no violation of the laws of physics, it works just as a hub gear on a bicycle. The force that the wind exerts on the propeller is greater than the force of aerodynamic drag holding the car back. Just like a bike wheel can rotate faster than the pedals, but with less force. It's a gearing up situation, greater velocity but with less force. The ground is an anchor point, a fulcrum for the lever.
bsam20uk 1 year ago
AWESOME!
sonicoliver 1 year ago
Love it. It made my mind pop but it makes sense. The "virtual" wind speed at the propeller is actually the speed of the vehicle plus the speed of the wind, not just the wind speed, so there's extra energy to be used? Fantastic.
damiensturdy 1 year ago
Amazing stuff, nice video!
EdLoveFilms 1 year ago
"ride with the wind"
*singing*
xtom1973 1 year ago
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Um...... "hey guys, heres a though! Lets build a machine that can go downwind faster than the wind and spend a shit load of money on something useless!!!!"
Yeah I don't get the purpose of it.
Pyr0Maniac01 1 year ago
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@Pyr0Maniac01 "Yeah I don't get the purpose of it." Well that proves you can't read and are a cretin. But why tell the world?
fizzguts 1 year ago
@Pyr0Maniac01 "Yeah I don't get the purpose of it." And thus you join that peculiar group of people at the first balloon flight, first public demonstration of the Wright flyer, the first demonstration of a steam propelled ship, Columbus's return, etc etc etc, who say "It's all useless" Never so happy as when you are bagging someone who has made an effort to push a boundaries. Get a life for gods sake
fizzguts 1 year ago 4
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@fizzguts You contradict yourself. Do you just cruise you tube all day long and troll the comment sections. lets look at your comment history ,Oh shit you do! 1 hr ago negative comment 7hrs ago negative comment 8 hrs ago negative comment 9hrs 10 hrs Wow all the way back to 2 days and not a single positive or constructive comment. At 59 years old I think you are the one that needs to get a life, or even better, GET A FUCKING JOB!
charliewecker 1 year ago
Very Cool.., where is this lake bed playa at?
thegoldenbear6621 1 year ago
@thegoldenbear6621
El Mirage, California.
piratewoodleg 1 year ago
It hurts my brain >_<
HooblyGoob 1 year ago
@HooblyGoob Too much Recon
BassMasterCHS 1 year ago
You don't have to have a degree in maths or use any maths at all to see how this works. It's really just common sense. The craft doesn't care if the ground is moving or the air is moving. (How could it know?) It's the relative movement that counts. So it can make progress over the ground, driven by the wind, or it can make progress through the air driven by the ground. However, this kind of "upsidedown" thinking seems beyond most people.
ZKMX7 1 year ago 5
This must be a hoax. Consider what happens if the vehicle reaches the exact speed of the wind. At that point the propeller will be in exactly the same situation as if there was no wind at all. What these people are presenting is that this device could start in zero wind and accelerate to a considerable speed. Come on! Perpetual motion machines do not work .
If there is no hidden energy source in the device, such as a battery/motor then it works by storing up energy first like a friction toy car
aylesmerep 1 year ago
@aylesmerep
It is not a hoax. The record has been verified. Google "nalsa downwind"
At "windspeeed" is NOT the same situation as with "no wind": The ground speed is different.
Of course it stores energy, when it accelerates. But it cannot use that energy to accelerate or even keep a constant speed, because it cannot slow down any parts, without slowing down the entire vehicle.
eyytee 1 year ago
Great effort many thanks for sharing
fizzguts 1 year ago
this make me thinks an eternal-motor is near. Some years ago I formulated an idea mixing wind;sun;thermal;magnetic and; vibration. to formulate just for fun the possibility of an eternal-motor. I'm brazil(sorry for my english), but if your brilhant mind interested on my ideias, I live for science.
god bless your criation!
MichelFurlanNirvana 1 year ago
it did 2.8 times the wind speed
creators blog:
fasterthanthewind -dot- org.
axelerat3d 1 year ago
Lets get this thing on the ice this winter. Come to Madison WI this winter and we can help you with the runner arrangement and see it go on a frictionless surface. Check out our web site at iceboat.org
kmetzloff 1 year ago
@kmetzloff
bad idea. this one needs friction to work. your iceboats also need friction in the lateral direction to go really fast. with no friction at all, you would just drift along with the airmass.
eyytee 1 year ago
How fast did it go then? tanks
8wealthyone8 1 year ago
Whats next flying machine or a trane?
Sonyoooo3 1 year ago
@Sonyoooo3 *train
MythOfEchelon 1 year ago
yall are all retards. I am not even going to bother explaining this to you bc you will rule it as incorrect and then go about making up some more bullshit on how it works.
justinccaudle 1 year ago
:O, antes de ver este vídeo creía que sería posible (con otros modelos)... pero ahora este vídeo muestra algo que me hace cambiar de opinión. miren en 1:15 el viento viene desde atrás del vehículo, pero las aspas giran en sentido contrario al viento (deberían girar al otro sentido o por ultimo frenarse, pero va en una aceleración constante)... según yo (un ignorante cualquiera) debería recién adquirir su propulsión en 1:41 ¿no será que tiene un motor auxiliar?
kotteshiro 1 year ago
captain planet's ride
EmperorOfMars 1 year ago
wow
joni9780 1 year ago
This comment has received too many negative votes show
what a waste just use a kite, or sail. You'll go much faster.
johnmcudd 1 year ago
@johnmcudd
How could a kite or sail ever drive a ddwfttw cart? That makes no sense. They obviously will max out at (actually somewhat under) wind speed when going directly downwind.
EebstertheGreat 1 year ago
@EebstertheGreat You can go faster than the wind by cutting across the wind; then turn downwind. At that moment you would be travelling downwind faster than the wind, before slowing down.
planetofthescums 2 months ago
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*sigh*. Look the wind pushes on the blades which pushes the cart forward and starts to turn the tires which starts turning the propeller against the wind. It's obvious in the video. It's possible because the cart is extremely light and the wind is strong. This continues until the cart is going as fast as the wind at which point the propeller is going fast enough to push the cart to the next stage. Just google dwfttw and read the blogspot.
ZazuYen 1 year ago 5
Comment removed
ZazuYen 1 year ago
So this vehicle is going faster because it is using a transmission to "convert" the radial speed of the windmill into faster radial spin of the wheels?
pebre79 1 year ago
@pebre79
no as explained earlier, the wheels spin the propeller that pushes the air backwards - against the wind. at low speed the prop is acting as simple wind catcher not much unlike a parachute or anything with drag. As the vehicle accelerates the prop starts acting.
axelerat3d 1 year ago
@pebre79 The speed of rotation is called "angular velocity".
(Radial spin and radial speed are each different and separate terms.)
Looking at a bicycle, the speed of both sprockets, the one driving the chain and the other driving the wheel, are both equal; along with the chain's speed.
Without understanding the correct terminology it gets confusing.
The angular velocity however changes with each radius.
planetofthescums 2 months ago
@pebre79 Notice, however, the sprocket driving the wheel and the wheel itself have the same angular velocity and two different speeds.
The same is true for the pedals and the sprocket driving the chain.
There is some sort of conversion although at this point I do not know what it is, it is completely related by radii. There are many possible combinations; the wheels may actually be driving the fan blades.
planetofthescums 2 months ago
@DanFrederiksen Until the point at which the tailwind becomes a headwind, around 1:40, at that point it becomes like a windmill with the prop driving the wheels rather than the wheels driving the prop. It creates it's own feedback loop. Very clever indeed.
ZazuYen 1 year ago
@ZazuYen
not correct. The propeller keeps spinning the same direction and all the time keeps blowing air backwards.
axelerat3d 1 year ago
@axelerat3d
True the propeller never changes direction, but once the tailwind has become a headwind it is no longer pushing the air but is being pushed BY the air.
ZazuYen 1 year ago
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@ZazuYen "True the propeller never changes direction, but once the tailwind has become a headwind it is no longer pushing the air but is being pushed BY the air."
.
The propeller is ALWAYS pushing the air backwards, against the direction of the TRUE wind. Wind energy ALWAYS comes from reducing the TRUE wind.
eyytee 1 year ago 3
epic
240SSONLY 1 year ago
@240SSONLY indeed...
AppleTechnologyGuy 1 year ago
eh, if the wind is from behind, howcome the prop spins as if the wind is from the front?
DanFrederiksen 1 year ago
@DanFrederiksen
because the wheels are geared to the prop and force it to spin that way. It is not acting as a windmill but as a pusher prop.
axelerat3d 1 year ago
@axelerat3d ahh! I see. that's really weird but makes sense.
the forced prop creates its own higher speed air cushion with which it is in turn again forced. clever
DanFrederiksen 1 year ago
@axelerat3d That doesn't make any sense. If the wheels are geared to drive the prop, where's the initial starting force coming from? Magic? Even if true, it seems rather pointless - the reason it can go faster than the wind is because of the gear reduction ratio between the prop and the wheels; it has nothing to do with any weird wheel-prop-feedback nonsense.
c6gunner 1 year ago
@c6gunner
maybe my explanation wasn't the greatest BUT the prop is blowing backwards. Not acting as a "windmill". What gives the initial start? the wind of course. If the propeller could spin freely the wind would make it spin the other way.
axelerat3d 1 year ago
@axelerat3d No, that's stupid, and completely wrong. If the prop were acting as a pusher, you'd need an engine to spin it. You don't get to use the wind to spin a prop, and then magically have the same prop push air backwards. You obviously have no clue what you're talking about.
c6gunner 1 year ago
@c6gunner
Really - why don't you go and read the creators blog where it is very clearly explained. Also you see it very clearly on several of the slow start of the cart that it is indeed a pusher. What spins it? the wheels. Not vice versa.
axelerat3d 1 year ago
Comment removed
c6gunner 1 year ago
Comment removed
c6gunner 1 year ago
@c6gunner
I see you pulled your comments on me making shit up and having a losing strategy. and having no pride... Maybe you should concentrate less on insults and try to follow what others try to explain - even if you don't agree you shouldn't shut down before you give it some thought. No need for insults. AND now the exact quote from one of the co-creators:
axelerat3d 1 year ago
@axelerat3d
""The downwind car is designed with a propeller that pushes it along like an aircraft's propeller does, it is not a windmill or a turbine. Instead of an engine to turn the propeller, the propeller is geared to the wheels of the car, so that as the car moves forward, the propeller spins in such a way that the car will speed up if there is energy available from a tailwind."
google the quote or find the link in the blog
axelerat3d 1 year ago
@axelerat3d Yeah, that explanation is garbage. They're describing a perpetual motion machine. The wind pushes the car, which spins the wheels, which spin the prop, which pushes the car, which spins the wheels, ad-infinitum. Sheer nonsense. They either REALLY suck at explaining what they've done, or they have no idea how their own vehicle actually works.
c6gunner 1 year ago
@c6gunner
well it does work. And it ain't perpetual motion. P=FV so when traveling downwind your wheels relative speed to the ground is higher than the props speed in relation to the wind.
So test that idea with different numbers FV[wheel-ground]>F[air-prop]
You will see that with 10N braking force you can create 20N pushing force. Its just like a transmission in purely mechanical system - you trade speed to torque - or in this case thrust.
axelerat3d 1 year ago
@axelerat3d I was being vague - with my 10N -> 20N. In certain conditions that can be true. Basically there is plenty of room for efficiency losses.
And the damn cart just did 2.8 times downwind speed...
axelerat3d 1 year ago
@axelerat3d I'm not questioning whether it works. We know that you can go faster than the wind. The question is HOW does it work, and your repetition of their formulas (or your incorrect usage of the term "pusher prop") does nothing to explain that.
At first, the prop probably works as little more than a sail. With variable-pitch blades it could also work directly on the wheels. Once it gets up to zero relative velocity, that's where it gets interesting, and their explanation makes no sense.
c6gunner 1 year ago
@c6gunner
Suit yourself. Tell me:
if the cart is going 9m/s in the direction of the wind of 10m/s and the wheels are "braking" with force 20N how much thurst in Newtons can the prop create from that force if we exclude all losses?
Answer 9m/s*20N= 180w and 180w can create thrust of 180N as the apparent speed for the prop is only 1m/s. F=P/V =180w/1m/s=180N
Of course in reality prop is very inefficient in certain conditions etc. so the situation is not as good but principle is correct.
axelerat3d 1 year ago
@axelerat3d If the wheels are braking with a force of 20N, you'll be losing power, not creating more. Multiplying numbers together randomly makes you sound all scientific to the layman, but it's still meaningless drivel. Look I can do it too:
If the flux capacitor generates 33 million newtons, and the car is moving at 80 miles per hour, how much power can the wheels create? P=V*F=1.2 gigawatts! Therefore time travel IS possible!
c6gunner 1 year ago
@c6gunner
All you have is insults.
- My calcs are not random
- the cart works
- prop blows air (does not act as turbine) as stated by the creators of the cart
- You don't understand how it works yet you don't even try to get it. Instead you resort to 'not so clever' insults.
Have a nice life.
axelerat3d 1 year ago
@axelerat3d Ah, yes, the final retort of every incompetent: "It's not my fault that I can't explain it, you just don't want to understand!"
Actually, for the record, I've found some forums that do a much better job of explaining the process. I need to crunch some numbers, but the concept seems valid. I suppose I should thank you for trying, at least. I admire your tenacity, if not your communication skills :)
c6gunner 1 year ago
@c6gunner
whatever man,
you wrote:"No, that's stupid, and completely wrong. If the prop were acting as a pusher, you'd need an engine to spin it. "
and
"Just admit that you're making shit up, and move on. There's more honour in surrendering and admitting a mistake than in pursuing a losing strategy. "
and
"Multiplying numbers together randomly makes you sound all scientific to the layman, but it's still meaningless drivel."
and you complain about my explications. Nice!!
axelerat3d 1 year ago
@axelerat3d
eh explanations... spellchecker error...
axelerat3d 1 year ago
@axelerat3d Explications is a word and you used it correctly.
planetofthescums 2 months ago
@axelerat3d Yes, your"explications" sucked. Oh, and BTW, the term "pusher prop" still doesn't apply to this vehicle.
c6gunner 1 year ago
@c6gunner
axelerat3d's explanations and calculations are fine. It is a propeller, powered by the shaft, creating thrust, even in still air or apparent headwind. You don't need an engine for that, just the right gearing and a velocity difference between the two media. There are different ways to explain it. Just because you don't get one of them, doesn't mean the explanation is wrong.
Do the math, instead of making claims based solely on your gut feeling and everyday experience.
eyytee 1 year ago 24
@eyytee It's got nothing to do with "gut feeling and everyday experience". The entire problem is the inability of these people to explain what it is they're doing. Talking about a propeller pushing wheels and wheels spinning the propeller is guaranteed to get them dismissed as a bunch of cranks. If they had any clue how to communicate their ideas to others, they'd have been taken more seriously from the beginning instead of being ridiculed by damn near everyone.
c6gunner 1 year ago
@c6gunner
But "propeller pushing wheels and wheels spinning the propeller" is a correct explanation. The only missing bit is, that the propeller is not doing the pushing alone, but is supported by the movement of the air mass.
It is a brainteaser. You are supposed to find out yourself how it works. Or at least learn enough physics to understand the explanation, not complain about the explanations. They were dismissed as cranks only by people who "know some physics", but cannot do the math.
eyytee 1 year ago 3
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@eyytee lol. No, they were dismissed as cranks by EVERYONE. The only people who took them seriously were the woo-purveyers (some of whom have commented here) who believe all sorts of stupid shit.
It's cute how you're trying to make excuses now, but the reality is that science depends on clear explanations and reproducible experiments. If you can't explain what you've done, you shouldn't expect to be taken seriously.
c6gunner 1 year ago
@c6gunner
what a fool. Check eyytee's videos and mine. We have spent some time explaining this - not because we are in anyway involved with the cart but because we find it an interesting dilemma. You act like we have some kind of responsibility to to make YOU understand. It ain't so.
Science is not based on the idea that everyone should get it. Not at all. The creators of the cart understand very well how it works and now they have proved that it does. You would get it too if you tried.
axelerat3d 1 year ago 31
@axelerat3d
>>Science is not based on the idea that everyone should get it.<<
Ha ha ha
disappearences 1 year ago 2
@c6gunner
No, they were not dismissed as cranks by everyone. Mostly just by wannabe-sceptics, who are often not much smarter than actual cranks.
Their explanations were clear. Their experiments were easily reproducible.
But there are two kinds of people: Those who need no explaining, and those whom no explanations can help.
eyytee 1 year ago 6
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@eyytee No, they were dismissed as cranks by everyone. Stop pulling excuses out of your ass.
c6gunner 1 year ago
@c6gunner
You confuse "majority" with "everyone". And I have no need to give excuses, for your failure to understand something. This cart works fine without you understanding it.
eyytee 1 year ago 6
@eyytee You apparently do feel a need to give excuses for your inability to communicate. Which is as it should be. It would be much more efficient to accept that you are an idiot when it comes to explaining / teaching, instead of repeatedly whining about it not being your fault.
c6gunner 1 year ago
@c6gunner
You are whining that you don't get it.
You are trying to excuse it, by the silly claim that everyone is just as ignorant as you are.
It would be much more efficient to accept that you are an idiot when it comes to understanding physics, instead of repeatedly whining about it not being your fault.
eyytee 1 year ago
@eyytee No, dumbass - I get it just fine, I'm simply pointing out that you're incompetent.
c6gunner 1 year ago
Comment removed
eyytee 1 year ago
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@c6gunner
If you would really get it, you would not insult axelerat3d and say that his explanations & math are wrong.
I'm simply pointing out that they are correct.
eyytee 1 year ago 8
@c6gunner
LOL, Yeah, you totally "get it" now. Better than the guys who build it, because their explanations are wrong according to you. But a guy like you, who doesn't even understand P = F * v and thinks it just "multiplying random numbers", surely has a much better explanation.
So let's hear it! Please explain to us how it works.
piratewoodleg 1 year ago 4
@eyytee The minority may not include the cranks and illigetimate critics. It would have to be credible scientists who think the explanation is worth a second look.
I have an inkling that machines travelling downwind faster than the wind are nothing new.
planetofthescums 2 months ago
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@c6gunner
Stop making excuses for your own ignorance, by claiming that everyone else is as ignorant as you.
piratewoodleg 1 year ago 7
@eyytee You must show the direction of the force and the magnitude of the force for your explanation to be of any use to us. Simply saying the air pushes the propeller which pushes the wheel which turns and pushes the air may be "correct", but it makes no difference because it is not detailed enough of an explanation.
Saying it can move in STILL AIR makes your explanation of how the propeller works completely false, the only way you can do this is by having an ENGINE (treadmill).
planetofthescums 2 months ago
@planetofthescums
- For force vectors check my video: "Directly Down & Up Wind Faster than the Wind".
- By "still air" I meant zero relative wind, not zero true wind. This cart doesn't work without true wind. But its propeller still works in zero relative wind and slows down the true wind.
eyytee 2 months ago
@eyytee I saw that video and I won't comment on it.
If you would like to look at it from the frame of reference of the cart, then lets stay on the cart.
You are in zero relative wind and you are standing on the front of the cart, facing the propeller.
The propeller is spinning anti-clockwise.
This pushes air away increasing the speed by which you are reversing.
The only reason the propeller is spinning is because of the wheels turning on the ground; so the propeller begins to slow down.
planetofthescums 2 months ago
@eyytee From the perspective of standing on front of the cart looking rearward, the air was initially moving toward your face. At a certain point the the air stops and then is blowing against your back.
My explanation is that the prop did not cause turbulence while it slowly built up speed, the air was slowing down, and blowing behind it (passing eachother). This allowed the prop to build up inertia.
At a key point the propeller causes turbulence and then pulls air forward. (Watch your fingers.)
planetofthescums 2 months ago
@eyytee This is why your explanation is hard to digest, because you said the propeller pushes the wind and the wind pushes the cart. This not true from the same perspective or the same time frame.
I haven't done any mechanics, but I imagine this is what is important. I also imagine this is what is going on.
planetofthescums 2 months ago
@axelerat3d Actually all calculations are made up drivel.
planetofthescums 2 months ago
@c6gunner
"If the wheels are braking with a force of 20N, you'll be losing power,"
Yes you will be braking with 20 N but as in the example you can push with 180N you have excess of force -> acceleration.
If you took over 30 seconds to consider the fact that the wheels and the prop have interaction with different speed mediums you would get that 20N can easily be geared to be much more in the other medium. Equal power can be geared to different forces.
axelerat3d 1 year ago
Richard, are you insprired to start a project for a DDW specific and speed record yet? Forget the multiple of wind speed, just design for higher winds and rip up that lake bed!
Cloxxki 1 year ago
All it takes is someone telling spork & JB, that it is impossible to break Richard's record with a DDW-vechicle, and these guys will build one and do it.
eyytee 1 year ago
@eyytee
You sure have a point there. With their way of covering their progress, it should be quite a ride, even for those following the project on the internet.
Cloxxki 1 year ago
@Cloxxki
We certainly appreciate the vote of confidence, but if we set out to break Richard's record, the first step will be to get Richard on the team.
spork33 9 months ago
@eyytee
Quite sure you are right. But it would be nice to see some competition.
Cloxxki 1 year ago
Thanks Richard, nice meeting you, we appreciate the great video and comments on the blog. David
davidglover 1 year ago
Awesome!
NMERider 1 year ago