Mess with your minds: A wind powered craft going faster than a tail wind speed.

[gnuarm]

Then he takes close up photos of gears nearly slipping and talking as if the micro level of energy involved in that is providing the necessary energy for faster travel.  It's pure BS.

The whole stick-slip hysteresis energy storage explanation is silly.  If there is a stick-slip cycle then energy is stored and released during the cycle.  If ED's explanation were true, the vehicle would be varying above and below windspeed at the cycle rate.  But the downwind speed of the vehicle through many of these nonexistent "cycles" remains faster than windspeed.

Exactly.  So he has to claim the storage is in the air around the propeller as if this would actually power something meaningful.  It only exists because it is continuously replenished and constantly depleted as fast as the air moves through the propeller.  So very, very little stored energy.

This guy is starting to bug me.  We call him on his crap and he pulls more crap out of his crap bag.  But I guess it's a matter of fool me once, shame on you.  Fool me 5,067 times, shame on me.  We just can't seem to stop responding to him. 

I bet it would really bug someone for the conversation to be only between others, but not directly to him.  lol

[gnuarm]

If you are talking about the propeller generating thrust, that is downwind.  So the propeller is pushing the front wheels down. 

In upwind mode the prop is a windmill.  It creates drag which will tend to shift the weigh so the front wheels could lift.  The car would be better operated with the prop in the front. 

I don't follow at all about the front wheels lifting for lower drag causing the car to accelerate.  Do you mean the drag of the wheels on the road?   

[fourfathom]

Here's something that had me confused:

Bicycle stopped in the wind.  Wheels are not turning.  Brakes are locked (or wheels are bolted to the ground -- same thing).  There is force, but no movement, so no power.

Now, replace the brakes with a stalled motor.  There is still no movement, just two opposing forces (just as in the previous situation).  But the motor requires power (V*A) to remain stalled.  This power is being turned into heat.  I assume that we just consider that the motor is operating at 0% efficiency?  But it is providing torque. 

Or replace the motor with an electromagnetic solenoid that holds the bicycle in place against the wind -- really the same situation as the stalled motor.  In both cases power is being consumed, but no work is being done other than heating the air?

It seems to me that some of ED's confusion is related to this.  I know I still struggle with the terms, since I always go back to the volts and amps.  ED's models using generator and motor also add to the potential (no pun intended) confusion.

[bdunham7]

Now, replace the brakes with a stalled motor.  There is still no movement, just two opposing forces (just as in the previous situation).  But the motor requires power (V*A) to remain stalled.  This power is being turned into heat.  I assume that we just consider that the motor is operating at 0% efficiency?  But it is providing torque. 

For a motor, efficiency is the work done by the motor as a percentage of power input.  So if it does zero work, it is 0% efficient.  However, the motor can be made arbitrarily efficient to have arbitrarily small losses, at least theoretically.  If the motor is actually doing a certain amount of work (output) then it has to have at least that much input power, since it can't exceed 100% efficiency.  However, if it is doing zero work, as in a stalled motor, you an reduce the input power to an arbitrarily low number.  As a trivial example, lets say your motor requires 5 amps at 60 volts to provide enough torque to hold a bicycle in place with a headwind--300W.  If we assume a motor that has a torque proportional to the input current, then we can use a 10:1 gearbox so that the motor only needs 0.5 amps to hold the same bicycle against the same headwind.  IOW, the work being done by the motor (output) is simply the lower bound for input power.

[IanB]

Here's something that had me confused:

Bicycle stopped in the wind.  Wheels are not turning.  Brakes are locked (or wheels are bolted to the ground -- same thing).  There is force, but no movement, so no power.

Now, replace the brakes with a stalled motor.  There is still no movement, just two opposing forces (just as in the previous situation).  But the motor requires power (V*A) to remain stalled.  This power is being turned into heat.  I assume that we just consider that the motor is operating at 0% efficiency?  But it is providing torque.

Remember that gearing can be placed between the motor and the wheels. Also, there is a property of gear trains that sometimes they can only go one way. For example, a worm drive. If you turn the input to a worm drive, the output will turn. But if you try to turn the output, it will not move. No matter how much force you apply to the output of a worm drive you cannot drive it backwards. So the vehicle will sit stationary in the wind until you turn the input to the gear train, and this will then need little power to make it move.

So once you have this situation, you can just put a really tiny motor on the input to the worm drive, and as long as the gearing is high enough, the tiny motor can move the output against an arbitrarily large force. This is just the principle of levers applied to rotation. Given a big enough lever, you can lift a mountain with the weight of a feather.

[Labrat101]

I don't follow at all about the front wheels lifting for lower drag causing the car to accelerate.  Do you mean the drag of the wheels on the road?

I think you will find the blackbird gearbox is on the back wheels as I remember it's a chain and cog drive . So the front wheels are only for supporting the front & steering..
In thrust the noise will lift . It's an aerodynamics it will rise against thrust due to centrifugal force from the prop and air under the fuselage.
I am Not going into a mile of advanced math in aerodynamics.  Take it as is . It does and will.
 

[IanB]

I think you will find the blackbird gearbox is on the back wheels as I remember it's a chain and cog drive . So the front wheels are only for supporting the front & steering..
In thrust the noise will lift . It's an aerodynamics it will rise against thrust due to centrifugal force from the prop and air under the fuselage.
I am Not going into a mile of advanced math in aerodynamics.  Take it as is . It does and will.

But it doesn't really matter, and has no relevance to anything important about how the vehicle works. So it is best left to one side, or it will just become another red herring to divert the discussion.

[Labrat101]

Ok
Can I just say I need to know how
Much energy is required to open a bottle
Of good whiskey and get drunk.
Happy new year 🎉
..
No more off topics. 

[fourfathom]

Remember that gearing can be placed between the motor and the wheels. [...]

No, I'm comfortable with all that, it's just the fundamental discussion of work, energy, force, etc.  And I'm actually pretty good with those as well.  It's just where does the motor (or solenoid) power go, if not into motion?  I think the answer is "heat".

As for upwind, I see no need to bring that in, other than as an interesting implementation detail.  Direct upwind movement, using a vehicle-mounted wind-driven generator (or mechanical gear drive) is easy to demonstrate and understand.  Okay, I suppose we can also consider DDWFTTW as "upwind", so perhaps some insight into the question can be gleaned.

And why bother discussing feathering props?  Yes, these can improve efficiency, but fixed-props have been shown to work in DDWFTTW tests.

[IanB]

No, I'm comfortable with all that, it's just the fundamental discussion of work, energy, force, etc.  And I'm actually pretty good with those as well.  It's just where does the motor (or solenoid) power go, if not into motion?  I think the answer is "heat".

Right, but the key thing is the motor the doesn't need any input power if the vehicle is stationary, because the vehicle is held in place by the gears that can't turn backwards. So from that stationary starting position, any tiny bit of power applied to the motor can make it turn forwards. There is no need for any "holding torque" on the motor to waste power as heat.

But clearly if you stall an electric motor by preventing it from turning when applying power, then the electrical power will be dissipated in the windings as heat (and may burn out the motor if it persists for too long).

[fourfathom]

Right, but the key thing is the motor the doesn't need any input power if the vehicle is stationary, because the vehicle is held in place by the gears that can't turn backwards. So from that stationary starting position, any tiny bit of power applied to the motor can make it turn forwards. There is no need for any "holding torque" on the motor to waste power as heat.

Yes and no. 

My thought experiment posits a motor directly connected to the wheel, via gears if you like,  but in a completely linear fashion where the wind can cause an un-powered motor to rotate in either direction.

But even with your one-way gearing, you will need more than "any tiny bit of power" to get the motor to turn.  The motor needs to generate sufficient torque to overcome the (head wind) wind-force.  Whatever your gear-ratio, there will be some minimum amount of power needed to make the motor spin.  Otherwise the motor is stalled and power turns into heat.

[PlainName]

you will need more than "any tiny bit of power" to get the motor to turn

I think you may be picturing this in your mind, seeing pretty big gears or pulleys, and figuring you need a substantial motor even so. But perhaps those big gears are several orders of magnitude too small, and the stress may break gear teeth in reality but for the purpose of this exercise it's not going to happen.

[thm_w]

Why can you put 300W and go at low speed when climbing a hill ?
Why do you think driving in head wind is any different in that regard?
The bicycle speed will be low but your gear ration can be set so that your legs move very fast thus even with low force needed at the pedals you can still produce 300W
There is a limit based on when the traction wheel will start to slip but 300W even at 1km/h is possible on a bicycle.

This was already explained to you, 1km/h is not possible at maximum power (~60rpm) on any common bicycle. Use the gear speed calculator link I provided to understand.
You can put hill gradient into the watt calculator as well if you are curious: https://www.omnicalculator.com/sports/cycling-wattage

Just please don't come back and say "100% gradient can't be done on a bike, the calculator is wrong!"
https://www.cyclist.co.uk/in-depth/682/how-steep-is-too-steep-when-cycling-uphill

[thm_w]

you will need more than "any tiny bit of power" to get the motor to turn

I think you may be picturing this in your mind, seeing pretty big gears or pulleys, and figuring you need a substantial motor even so. But perhaps those big gears are several orders of magnitude too small, and the stress may break gear teeth in reality but for the purpose of this exercise it's not going to happen.

Their point is correct though, I believe.
You still need some minimum amount of torque. But the thing with gearing is, if you have a large gear ratio, then this amount of torque would be incredibly low. Which means, required motor and power input can be very small.

50km/h wind acting against a bicycle (0.5m2), wind load is 60N. 10000:1 gear would bring that down to 0.006N. Of course this is theoretical, no real system uses gears that extreme. The largest worm gear I see on mcmaster is 120:1

[IanB]

Yes and no. 

My thought experiment posits a motor directly connected to the wheel, via gears if you like,  but in a completely linear fashion where the wind can cause an un-powered motor to rotate in either direction.

But even with your one-way gearing, you will need more than "any tiny bit of power" to get the motor to turn.  The motor needs to generate sufficient torque to overcome the (head wind) wind-force.  Whatever your gear-ratio, there will be some minimum amount of power needed to make the motor spin.  Otherwise the motor is stalled and power turns into heat.

The distinction between torque (rotation force) and power is where this thread was coming unstuck before.

Suppose, for a moment, that we have ideal, frictionless gears. It's not going to happen in the real world, but suppose we have Teflon gears and roller bearings and whatever.

Now, suppose we wish to move our vehicle forward at 0.1 m/s against a 100 N force of headwind. We can calculate the required power as 0.1 x 100 = 10 W. So, if there are no losses in our ideal gear train, then the motor needs to output 10 W to achieve this rate of forward progress.

If, maybe, we only have a 1 W motor, then we cannot go this fast. However, we could go at 0.01 m/s, since 0.01 x 100 = 1 W.

How big the motor is determines how fast we can go, but if we just want to go at any speed at all, then we can introduce ludicrous gear ratios and make the motor as tiny as we like.

This is why I say "any tiny bit of power". In the real world, of course, some power is required to overcome the friction in the gears, and more gears will have more friction, so there is a law of diminishing returns. However, in principle, a wind up clock mechanism could make a vehicle move against a gale force headwind, albeit at a glacial pace.

[fourfathom]

Yes and no. 

My thought experiment posits a motor directly connected to the wheel, via gears if you like,  but in a completely linear fashion where the wind can cause an un-powered motor to rotate in either direction.

But even with your one-way gearing, you will need more than "any tiny bit of power" to get the motor to turn.  The motor needs to generate sufficient torque to overcome the (head wind) wind-force.  Whatever your gear-ratio, there will be some minimum amount of power needed to make the motor spin.  Otherwise the motor is stalled and power turns into heat.

The distinction between torque (rotation force) and power is where this thread was coming unstuck before.

Suppose, for a moment, that we have ideal, frictionless gears. It's not going to happen in the real world, but suppose we have Teflon gears and roller bearings and whatever.

Now, suppose we wish to move our vehicle forward at 0.1 m/s against a 100 N force of headwind. We can calculate the required power as 0.1 x 100 = 10 W. So, if there are no losses in our ideal gear train, then the motor needs to output 10 W to achieve this rate of forward progress.

If, maybe, we only have a 1 W motor, then we cannot go this fast. However, we could go at 0.01 m/s, since 0.01 x 100 = 1 W.

How big the motor is determines how fast we can go, but if we just want to go at any speed at all, then we can introduce ludicrous gear ratios and make the motor as tiny as we like.

This is why I say "any tiny bit of power". In the real world, of course, some power is required to overcome the friction in the gears, and more gears will have more friction, so there is a law of diminishing returns. However, in principle, a wind up clock mechanism could make a vehicle move against a gale force headwind, albeit at a glacial pace.

Yes, 100% yes.  With an arbitrary amount of electrical power applied to the motor, and an appropriate gear ratio, the mechanism will move forward at some speed.

But I think we're talking past each other.  ALL I AM SAYING IS THIS:

• There is a force acting on the mechanism.  Let it be a head wind.  With no brakes and no friction, the mechanism will roll backwards at wind speed.
• An electric motor is used to counteract this force.  Just enough power is applied to the motor (volts * amps) to hold the armature in one place.  This is a locked rotor.
• Since the mechanism is not moving, there is no mechanical work being done.
• But the motor is still consuming power, turning it into heat.  The motor is operating at 0% efficiency, but still performing a useful function.

This -- electrical power being used by the motor while no mechanical work is being done -- may be one of the confusing factors when discussing the system.  If the electrical motor were replaced by a wind-up spring-powered motor, and the motor torque were (through gears) equal to the opposing wind force, then I think there would be less confusion.  The motor would be stalled, nothing would consume power, and no work would be done.

[IanB]

• There is a force acting on the mechanism.  Let it be a head wind.  With no brakes and no friction, the mechanism will roll backwards at wind speed.
• An electric motor is used to counteract this force.  Just enough power is applied to the motor (volts * amps) to hold the armature in one place.  This is a locked rotor.
• Since the mechanism is not moving, there is no mechanical work being done.
• But the motor is still consuming power, turning it into heat.  The motor is operating at 0% efficiency, but still performing a useful function.

This -- electrical power being used by the motor while no mechanical work is being done -- may be one of the confusing factors when discussing the system. 

OK, that's clear. I understand where you are coming from. I am also trying to make sure the information is clear for anyone else reading the thread.

This is a bit like the situation where you are holding up a heavy weight with your arm, without moving. In a physical sense, no work is being done because nothing is moving, but your arm is still doing muscle work and getting tired.

Situations like this are the correct use of energy balances. In this case there is a steady state balance that says:

   (total power in) = (mechanical power out) + (power dissipated as heat)

When talking about power, it is of course important to be clear about which measure of power is being discussed.

[gnuarm]

Here's something that had me confused:

Bicycle stopped in the wind.  Wheels are not turning.  Brakes are locked (or wheels are bolted to the ground -- same thing).  There is force, but no movement, so no power.

Absolutely correct.  Same as if the bike were laying on the ground or a car was laying upside down.

Now, replace the brakes with a stalled motor.  There is still no movement, just two opposing forces (just as in the previous situation).  But the motor requires power (V*A) to remain stalled.  This power is being turned into heat.  I assume that we just consider that the motor is operating at 0% efficiency?  But it is providing torque. 

That's one reason why I didn't want to involve a mechanism.  Mechanisms always have inefficiencies or other complications that muck up corner cases.  But yes, the power flowing into the motor is only to overcome inefficiencies in the mechanism.  Motors get max torque at zero RPM, so the current would not need to be high unless the force required were high.  In essence the motor has become an electromagnet.  It could be replaced with a permanent magnet.  In fact, I believe stepper motors have this effect, they have spots where the motor comes to rest and without any current flowing a force must be applied to move them from that spot.

Or replace the motor with an electromagnetic solenoid that holds the bicycle in place against the wind -- really the same situation as the stalled motor.  In both cases power is being consumed, but no work is being done other than heating the air?

Ah, great minds think alike. 

It seems to me that some of ED's confusion is related to this.  I know I still struggle with the terms, since I always go back to the volts and amps.  ED's models using generator and motor also add to the potential (no pun intended) confusion.

I can't imagine what ED's confusion is.  He has trouble understanding the energy is not related to time but power is.  He keeps posting the equation relating power to energy and time as if that proved something.  That's why I posted the true story of the guy who didn't know how to calculate the square footage of a room.  "How many quarters in two dollars?  See?"  This is ED's thinking.

Actually his issue is not about the waste heat of a motor or solenoid.  His problem is he doesn't want to be proven wrong so he continues to insist on applying a formula in a case where it is irrelevant... among many other mistakes.  The lady doth protest too much, methinks.

Feliz año nuevo

[IanB]

We should probably just let this thread rest at this point. It seems to have run its course.

[MikeP]

  Dear friends, thank you for a little adventure. Very funny!

   To electrodacus. Give up! opposition is useless! This device really works. Although the principle is not obvious.

 Yes, I have not read everything here. Perhaps I will repeat someone's words, sorry.
  Quite a long time ago, my friend voiced a banal thing - the mathematical apparatus is secondary. Understanding the principle is primary. In this case (electrdoacus) understanding did not happen. Therefore, all formulas are useless.
   And now, in essence. Perhaps this will help. The entire mechanism with a transmission and a propeller makes it possible to perceive wind energy at almost any speed. The basic ratio of wheel circumference to propeller pitch is 0.7. In other words, the propeller always "advances" the movement of the cart. Everything is very simple.
 

[electrodacus]

  Dear friends, thank you for a little adventure. Very funny!

   To electrodacus. Give up! opposition is useless! This device really works. Although the principle is not obvious.

 Yes, I have not read everything here. Perhaps I will repeat someone's words, sorry.
  Quite a long time ago, my friend voiced a banal thing - the mathematical apparatus is secondary. Understanding the principle is primary. In this case (electrdoacus) understanding did not happen. Therefore, all formulas are useless.
   And now, in essence. Perhaps this will help. The entire mechanism with a transmission and a propeller makes it possible to perceive wind energy at almost any speed. The basic ratio of wheel circumference to propeller pitch is 0.7. In other words, the propeller always "advances" the movement of the cart. Everything is very simple.

You mentioned that "everything is very simple".
I have the most basic question for you.

What is the wind power available to vehicle ?  A simple and of course correct equation will be good.

[Labrat101]

Easy the earth is Flat so as the elephants 🐘 move form side to side the wind is forced in a clockwise motion..
Scientists are wrong and we have all been lied to ..
Therefor if it works it's by luck and not by anything else ..

[eugene]

Are the scientists wrong, or are they deliberately misleading us for personal gain?

[Labrat101]

Are the scientists wrong, or are they deliberately misleading us for personal gain?

Good question.  I would say both.
There was an article in the G News .. a scientist made a quote .
Our sun will start dying in 5 billion years .. how will humans survive! 🙄
This has to be a good run up for a project.. . Should we panic of just wait  . I have a plan B .. watch from clouds.
99% of all the theories are BS.
Just money . The universe is also Flat . 🐣 or 🐓