Merged DDWFTTW in a “Real” Wind

[humber]

You watched the video where the tacking yacht morphs by stages into a propeller, didn't you? Which stage was wrong?

You are joking, right?

 

[Jack by the hedge]

It's nonsense. Silly.

Which part is nonsense, exactly?

Is the first part (showing a yacht tacking downwind faster than the wind) nonsense?

 

[Jack by the hedge]

You are joking, right?

I am absolutely not joking. I want to know which part of that animation you thought was wrong, and why.

 

[Llyricist]

The shoe is on the other foot, so there is no room for your nescience.
Answer to the electrical model. That has support other than your opinion.
Or are you now going to turn on your own expert, and add him to Spork's lengthy roll call of idiots?

You are going to swallow that upwind farce, whole, aren't you?

Everyone please note that he doesn't deny that he believes the cart will always travel the same distance through the air as it does over the ground.

I already answered to your ridiculous scenario "problem" with the electrical version, the air never aids the rotation of the prop, it always adds to the torque load that the motor must overcome.

 

[GlennB]

The peak speed of the cart is 28mph,

Therefore the wind must be regularly gusting at > 28mph ? Except ...?

but the average without the push is 8.5mph. Less than WS. Carteers do not see the significance of that.

You already made an idiot of yourself with this 'retained push speed' concept when we were discussing my car's fuel consumption. The point is that the initial push speed would be rapidly lost if the cart were pushed up to that speed in still air. The cart cannot 'retain' that speed in a real world that experiences friction. You simply cannot just deduct it from the max speed the way you do. Asinine isn't strong enough a word. Imbecilic might be more appropriate

 

[Llyricist]

No. You're still not paying attention.

The wind pushes the prop.

The prop pushes the cart.

The cart moves over the ground.

The ground turns the wheels.

The wheels turn the prop.

The power does not come from the wheels turning the prop. The turning is only required for the prop blade faces to present a bearing surface to the wind which is always travelling slower than the wind.

There are different ways of looking at this and explaining it. One is the tacking prop blade method, which you are using. And the other is the instantaneous power analysis from the FOR of the cart, which treats the prop as an actuator disk, which is what humber is objecting to.

Of course he can't handle FOR's, he treats motion as absolute, he isn't even aware of when he does change FOR's ("no tailwind above wind speed"), etc. etc.

In the instantaneous power analysis in the cart's FOR, the power does indeed come from the ground by the way.

 

[A.T.]

He[Randi] and I actually have traded a few emails, but he said something to the effect of "I'm not an engineer"

Admirable humility that sets him apart from wannabe-skeptics who try to debunk stuff they are clueless about.

 

[humber]

Therefore the wind must be regularly gusting at > 28mph ? Except ...?



You already made an idiot of yourself with this 'retained push speed' concept when we were discussing my car's fuel consumption. The point is that the initial push speed would be rapidly lost if the cart were pushed up to that speed in still air. The cart cannot 'retain' that speed in a real world that experiences friction. You simply cannot just deduct it from the max speed the way you do. Asinine isn't strong enough a word. Imbecilic might be more appropriate

There is no retention it is a simple fact v=at.

Trying to make sure you are singing from the same sheet?

All of you have different explanations. None of you thought about the ratchet. It's belief, pure an simple. That topic is dead. None of you have any mathematical support, so who cares?

The topic is the cart in the wind. You can have as many explanations as you like, but the trial is evidence, that says nothing special happened.
There is evidence of tampering, but that does not bother you.

So, who wants to show me that something did?
For example, find a reference that says wind direction may be defined by the mean of the readings over 10 seconds.

 

[Llyricist]

For example, find a reference that says wind direction may be defined by the mean of the readings over 10 seconds.

NALSA's rule book.

Now you find a reference that says wind direction may be defined by the RMS value of induced wind vane oscillation.

 

[A.T.]

The hub, root, and all other parts of the prop, move in the same direction as the cart.

You watched the video where the tacking yacht morphs by stages into a propeller, didn't you? Which stage was wrong?

Slowly Jack. Don't you see the problem here? He actually believes that the velocity of all points on a rotating object has the same direction.

Here another gem about the propeller kinematics from Talk Rational:

Does the distance between the tip and the hub change? No. So the tip travels at the speed of the cart.

 

[spork]

Admirable humility that sets him apart from wannabe-skeptics who try to debunk stuff they are clueless about.

Agreed

 

[D'rok]

It's nonsense. Silly.

You are joking, right?

Cogent analysis and convincing argument. Bravo.

 

[humber]

NALSA's rule book.

Now you find a reference that says wind direction may be defined by the RMS value of induced wind vane oscillation.

I am questioning NALSA's authority.

But, you should see that averaging makes no sense. Take a simple example where the wind blows +20 degrees for 5 seconds, and then -20 degrees for 5 seconds. Average = 0.
The wind relative to the cart, is no different from the cart relative to the wind, so is the same as jibing. So how would that be ddw?

It is not an excuse to say the wind is not suitable. It was already known from records that it would not be, so its not bad luck, but deception.

Same with the length of the run. Too short to gain steady-state. Yet, JB proposed a 2.5mile test where steady state was the aim, but accepted a 0.41 mile result and not steady state. They are crooks, and ambitious, you can expect more of the same for the upwind cart.

But you want that reference. RMS is the simplest method that can be justified by the limited data.
But should be based on the stadard deviation.
1- sd^2/2. And there is more to it than that.

 

[humber]

Cogent analysis and convincing argument. Bravo.

I am not interested in make-believe. I did not watch it.
The argument is one of mechanics, not faux hyper-space. So woo, as to be a cliche.

 

[humber]

Agreed

The difference is that I am not easily fooled. That bugs you.

Are you going to explain the filtering of the data?
NALSA rules say that filtering must be made explicit.

 

[D'rok]

I did not watch it.

Scared to, eh?

 

[humber]

Scared to, eh?

I don't want to see any Ben Stiller movies either.

Anything else?
Spork will not be back with an answer about the filtering. I wonder why that is.

 

[D'rok]

I don't want to see any Ben Stiller movies either.

Anything else?
Spork will not be back with an answer about the filtering. I wonder why that is.

Here it is. 57 seconds long. But too threatening, eh?

 

[humber]

Here it is. 57 seconds long. But too threatening, eh?

Sometimes avatars can be too ironic.

 

[D'rok]

Sometimes avatars can be too ironic.

Sometimes cranks can be too obvious. Unfortunately, I'm out of troll food for the moment. So do carry on.