Faster than the wind

[agor95]

Back to a real point, analogies are just a tool. Similarities and differences.

If wind and gravity were identical, it wouldn't be an analogy, now would it?

This is true an analogue by definition is different. But some are better than others.
For example an analogue computer predicting the tides.

[agor95]

It is simple leverage.

So the wind is the ruler, the main wheel is the prop' and the small wheels are the same.
As the small wheels propel the vehicle faster than the [wind/ruler].

The energy from the wind accelerates the vehicle.

Regards

[johannesbender]

Tarsier Yes I know how it works , when people say it goes faster than the wind , yes it goes faster than the wind , but it causes/caused confusion imo , because the wind force and speed from behind , is not the complete picture , however the description "faster than the wind" makes it sound like the only force to consider is the wind with its speed from behind , and not also the transformed thrust from the wind that contributes to the total force , unlike the graphed results which ignores the thrust.
I cant put it more clearly , feel free to ignore it.

https://youtu.be/yCsgoLc_fzI

[agor95]

I cant put it more clearly

In effect the initial wind pressure gets the vehicle moving. Then the dynamic blade shape takes over.
For the low pressure leading edge supplies the required force to continue.

Regards

[WaltzCee]

the description "faster than the wind" makes it sound like the only force to consider is the wind with its speed from behind , and not also the transformed thrust from the wind that contributes to the total force

First let me get this out of the way.
I have no idea what I'm talking about.

Now it seems to me, if johannesbender is accurate, the 2 forces are transformed thrust from the wind and the wind

The common denominator here seems to be the wind.

Wonder if that can be done with gravity.

Did you see what I just did?!?
That was Frank's question!

[johannesbender]

The forward propeller thrust is transformed from the motion of the wheels to the propeller with a MA speed ratio , no wheel motion then no propeller thrust , no push from behind from the wind then no wheel motion , I understand all that .

I do think it is possible in a gravity version with mass as the main form instead of wind , I had a theory that tries to demonstrates this effect however using the resistive force of air from the mass velocity, as mass velocity increases during a fall so does the resistance force of air , and when that force is transformed in to a forward push at a mechanical advantage enough to overcome friction in the same direction as the mass , the mass must accelerate and the resistance force must increase also etc etc. however i have not been able to design a mechanism.

[Tarsier79]

To be honest, it took a while for me to understand why it couldn't be done with gravity.

The underlying cause of the Blackbird speed is energy difference. When the energy difference between the wind and ground = frictions that is the max speed. In a gravity system, our energy source is the weight and its height (and speed). So we can get our mechanism to go faster than the weight drop, but not with more energy.

[johannesbender]

It must enter the acceleration phase (from 12 to 6 downward gravity) with a new total and larger velocity (above zero) each cycle to increase KE, max would be terminal velocity (theoretically).

[Tarsier79]

No

The energy in the wind is lost. It is transferred to the cart. The same goes for a wheel. You need to sacrifice one energy to get one to go "faster" than acceleration from gravity. The weight you sacrifice loses more energy than you gain. It will slow to a stop.

[Fletcher]

Fwiw .. this is how I tend to think of it, which I'll share. Personally I'm more interested in the science aspect (reasoning) than anything else.

First of all .. the experiments demonstrate without any doubt that Blackbird (BB) can can travel at about 3 times the true wind speed with the wind directly behind it. Both BB and wind speeds are ground speeds. And BB can travel at about 2 times the wind speed directly into a constant wind.

Second .. I tend to think of and reduce everything to momentum and energy where it can be done.

So let's look at a very hypothetical case as I don't know the exact figures so I'll use assumptions for those - feel free to check my math and reasoning, and conclusions.

Let's assume that the BB can do 2 times wind speed into wind, and use this example. Let's also assume the true wind speed is for arguments sake 10 km's per hour. That means BB can do 20 km's per hour into the wind.

At wind speed of 10 km/hr this equates to 10,000 meters in 3600 seconds = 2.78 m/s .. let’s round that up to 3 m/s for the exercise.

.. So BB could do 2 x 3 m/s = 6 m/s ground speed.

Let's take a look at momentum and energy exercises.

Air density at sea level is about 1.22 kg/m^3 .. let's for ease of calcs say it is 1.00 kg/m^3 ..

Let's assume the radius of the BB aerofoil (propeller) is say 3 meters. So it would have a swept area of pi x r^2 (pi = 3.1416 .. let's just use 3.00 m)

=> swept area of prop circle is 3 x 3^2 = 3 x 9 = 27 m^2 .. let's say 30 m^2.

Air speed of 3 m/s would imply that 30 x 3 = 90 m^3 is interacting with the prop swept area every second. IOW's 90 kgs of air mass each second.

Let's just round that up to 100 kgs per second for ease of calcs.

The moving air would have linear momentum and kinetic energy - what would they be ?

Airs Momentum => mv = 100 kg x 3 m/s = 300 kgm/s

Airs Kinetic Energy => m ½ v^2 = 100 kg x ½ x 3^2 => 100 x ½ x 9 => 450 Joules.

What is the BB’s Kinetic (rolling) energy (not including prop RKE) ?

Let’s assume with pilot it is 200 kgs all up at 6 m/s velocity (it could be far greater than that with much higher KE).

BB Momentum => 200 kg x 6 m/s = 1,200 kgm/s

BB Kinetic Energy => m ½ v^2 = 200 kg x ½ x 6^2 => 200 x ½ x 36 => 3,600 Joules.

Ratio of energies .. 3600 / 450 = 8 : 1 (remember the 4/5ths lift force from Bernoulli Low Pressure Zone suck or push + 1/5th from momentum transfer from air to wing in ‘Mechanics of Flight’). Not to different in this very gross analysis and we don’t know the efficiency i.e. coefficients of Lift and Drag for the BB but figures seem in the ball park.

Clearly the wind can only supply 450 J’s of energy of the 3,600 j’s of KE the BB has at constant speed. And there are drag energy losses etc not factored but real none-the-less

What’s happening ? And is it OU ?

It’s not OU because if there is zero wind speed BB has zero KE. It needs the wind gradient and KE to produce the BB KE.

And .. the air is not stopped i.e. it gives up a little of its mv and KE but not all of it !

So where is the energy coming from over and above the horizontal column of air impacting the swept prop area and being slowed down a little ?

The aerofoil prop creates a Bernoulli Low Pressure Zone forward of the prop. The BB is sucked into that Low Pressure Zone – or more technically correct it is pushed forward into the Low Pressure Zone from the surrounding halo of air rushing to equalize pressures. This means that all air surrounding the BB rushes in pushing it forward. This air moving in has momentum and KE.

So the energy budget is balanced because the earth’s air pressure provides the energy to push the air (and BB) into the forward Low Pressure Zone produced by the aerodynamic prop. IOW’s some energy comes from the air column wind speed interacting with the prop, and most comes from the surrounding air rushing in from all directions to fill the Low Pressure Zone created.

Conclusions :

1. BB’s KE is not OU. The energy budget is balanced when losses are accounted for etc.

2. The majority of the BB's KE comes from the pressure differential i.e. surrounding positive air pressure moving inwards to fill the negative air pressure void much like how a weather system of Highs and Lows operates.

3. We could mount the BB on blocks and attach a generator to the wheels to generate Watts as a comparison to ground speed KE achieved.

4. Within limits the BB could have a far greater mass and achieve a far greater KE but it would take longer to get to 2 times wind speed.

** check my maths and rationale – done on the back of a cigarette pack in a coffee break.

** open to other interpretations of where the energy comes from ?

[WaltzCee]

Conclusions :

1. BB’s KE is not OU. The energy budget is balanced when losses are accounted for etc.

OK.

If gravity slingshots a mass (w/mass entanglement) & the energy/power is transfered to the rotation, causing the wheel to accelerate producing more work, the energy can be accounted for.

Is this OU?

[johannesbender]

Apart from true wind there is also apparent wind.

https://en.wikipedia.org/wiki/Apparent_wind
"Windsurfers and certain types of boats are able to sail faster than the true wind. These include fast multihulls and some planing monohulls. Ice-sailors and land-sailors also usually fall into this category, because of their relatively low amount of drag or friction

In the foiling AC72 America's cup catamarans, the boats sail through the water at up to double the environmental wind strength. The effect of this is to radically change the apparent wind direction when sailing "downwind". In these boats the forward speed is so great that the apparent wind is always forward—at an angle that varies between 2 and 4 degrees to the wing sail. This means that AC72's are effectively tacking downwind, although at a greater angle than the normal 45-degree upwind angle, usually between 50 and 70 degrees."

I for one do not believe in energy out of nowhere , I believe all energy is just transformed or transferred as the familiar saying goes , so in my mind , a Bessler type of wheel (if it were to exist) would be an intermediate transformer / transferrer of energy's.

[Fletcher]

If gravity slingshots a mass (w/mass entanglement) & the energy/power is transferred to the rotation, causing the wheel to accelerate producing more work, the energy can be accounted for.

Is this OU?

Need more information Walt .. btw I read your comment as a statement and not a question.

Is your slingshot mechanism an articulated arrangement of levers etc ? The slingshot mech is pivot attached to a wheel !

All my sims to this point in time predict that the act of slingshotting a mass (as I'm imagining you are talking about) is conservative i.e. the whip effect is conservative => conservation of momentum and energy applies.

Do you have OU ?! - you do if the wheel accelerates and continues to accelerate while resetting itself during this process.

[Fletcher]

Apart from true wind there is also apparent wind.

https://en.wikipedia.org/wiki/Apparent_wind
"Windsurfers and certain types of boats are able to sail faster than the true wind. These include fast multihulls and some planing monohulls. Ice-sailors and land-sailors also usually fall into this category, because of their relatively low amount of drag or friction

In the foiling AC72 America's cup catamarans, the boats sail through the water at up to double the environmental wind strength. The effect of this is to radically change the apparent wind direction when sailing "downwind". In these boats the forward speed is so great that the apparent wind is always forward—at an angle that varies between 2 and 4 degrees to the wing sail. This means that AC72's are effectively tacking downwind, although at a greater angle than the normal 45-degree upwind angle, usually between 50 and 70 degrees."

For all yachts and ice-boats etc they can if designed well achieve tremendous across wind speeds, usually explained as apparent wind direction.

The acid test, and seldom discussed is the "track/velocity made good". TMG is the virtual track directly between course buoys (wind blowing buoy to buoy) and what the VMG boat speed is. For BB the VMG is higher than the wind speed by a large factor. No one has been brave enough to publicly analyse the the America's cup boats etc for VMG verses wind speed, probably because they sail across wind unlike BB and it would open a can of worms about OU and Perpetual Motion I would guess. Tho we know it isn't !

I for one do not believe in energy out of nowhere , I believe all energy is just transformed or transferred as the familiar saying goes , so in my mind , a Bessler type of wheel (if it were to exist) would be an intermediate transformer / transferrer of energy's.

I 100% agree !

[WaltzCee]

Do you have OU ?! - you do if the wheel accelerates and continues to accelerate while resetting itself during this process.

That is the goal. I'm thinking the debate is going to boil down to semantics.

Is your slingshot mechanism an articulated arrangement of levers etc ? The slingshot mech is pivot attached to a wheel !

Noether's first theorem. Yeah, it does seem impossible. Further, if I were to accomplish it, it would be a miracle!!

ETA
I don't agree with ex ni·hi·lo either.