Split Thread The validity of classical physics (split from: DWFTTW)

[semper]

Hi Humber,
have you ever heard of the Downwind Turning Myth for aeroplanes?

 

[CORed]

Some people are discussing gravity.

Humber are talking nonsense.

Thats the thread right now.

Humber talking nonsense has been the most consistent aspect of this entire thread.

 

[Furcifer]

3bodyproblem do you even know the principles that allow the cart to go faster than the wind? Of course you cannot start it from a dead stop on a treadmill. spork and company have found that for their improved cart it still takes a wind speed of about three miles an hour for it to go faster than the wind. With the cart at rest and zero wind speed it will naturally go backwards at first. Even if the wind generated starts to spin the props it will take a period of time longer than the cart will be able to stay on the treadmill. A very long powered walkway that you find at certain airports would be able to start the cart from nothing. I am sure that there are some conveyor belts that could be used also. But the typical home treadmill is way too short to give the results that you are demanding.

Um, yeah. About 2500 posts ago I stated that the prop essentially added mass to the system, exhibited as thrust. As long as the thrust is greater than the frictional losses in the system it will increase in velocity.

I have yet to see anyone to address the issue of the increase in velocity being linear or, as I suspect, oscillating rapidly about a point (with a net positive velocity wrt the wind). I'm not sure why, but I see it as "bouncing" off the air compressed behind the prop.

I agree that on a sufficiently long walkway the cart could start from rest. I would point out however, that the average airport walkway is probably too slow to do this. Feed belts on farm equipment are variable speed and probably long enough to do this. If I were going to do it.

 

[mender]

Funny things wheels. To generate force, one bit has to move a bit faster than another bit. You can wikki that. It is otherwise common sense, though. If the patch is to the rear;forwards, in the middle;stationary, to the front;backwards.

Really? Got a Wikki link?

You have it front to back again, humber.

 

[humber]

So when the Humber states that there can be no motion without force, it is as if he expects every problem in motion to require a common separate reference (but he cannot provide it).

Your words not mine, semper. I say that there is no need to provide a common separate frame. because all objects are in that frame, but if you like, may be viewed from different frames.

Since most of the debate here is due to Humber's unusual (or usual for uneducated or stupid people) methods of describing and interpreting motion, I thought it an interesting question.

Stupid? No more than the vain assumption that your ideas are not made of whole cloth.

 

[RossFW]

Yes. PM me.

You won't publically link to a commercial website?

 

[humber]

You won't publically link to a commercial website?

There is no website.They are available.

 

[RossFW]

Hi Humber,
have you ever heard of the Downwind Turning Myth for aeroplanes?

You know Semper, I had to once argue with the guy who was the chief Test Pilot of the Harrier, as HE subscribed to the "Downwind turn myth".


It has been suprisingly pervasive in Aviation.

It get's muddied because we ARE very aware of windshear, and the two get muddled.

Suffice to say I have made 180deg turns at 210kts indicated in 150kt winds to no ill effect!

 

[mender]

Um, yeah. About 2500 posts ago I stated that the prop essentially added mass to the system, exhibited as thrust. As long as the thrust is greater than the frictional losses in the system it will increase in velocity.

Adding a heavy propeller slows up the whole process of getting up to speed.

Mass exhibited as thrust? That sounds like one of humber's lines.

I have yet to see anyone to address the issue of the increase in velocity being linear or, as I suspect, oscillating rapidly about a point (with a net positive velocity wrt the wind). I'm not sure why, but I see it as "bouncing" off the air compressed behind the prop.

I'll give it a go if you like. I have been testing my cart downstairs on my treadmill and have a pretty good idea how the cart works.

 

[humber]

Adding a heavy propeller slows up the whole process of getting up to speed.

Mass exhibited as thrust? That sounds like one of humber's lines.

Almost the same. The cart is 'held in place' by the airmass. You can say that the cart accelerates away from that, but the motion that you see is relative to the ground not windspeed. So the same as a very slight breeze with the cart on the ground?
The treadmill has nothing to do with windspeed. It is pointless to consider longer belts.

 

[Furcifer]

Very nice. You're proven wrong, so you now call those that are right "childish" (because they're apparently fascinated by the same toy that fascinates you - only we understand how the toy works).

Prove me wrong on what?

I've never blogged a single word in my life. Your wrongness is truly impressive.

Now that's a lie and you know it. Shameful.

 

[mender]

Since most of the debate here is due to Humber's unusual (or usual for uneducated or stupid people) methods of describing and interpreting motion, I thought it an interesting question.

Now semper, I wouldn't call humber uneducated OR stupid or any combination of those two. His on the spot erudition and word play is indicative of a widely read and complex person. His diversity of experience and familiarity with unique niches of knowledge are quite fascinating. It's his bizarre excursions off the beaten physics paths that have kept this thread bouncing around for 3000 posts, and his interpretations of what he reads and sees that would lead someone to doubt (or praise in the case of recursed moppet) humber's ability to understand classical physics.

 

[spork]

As to my question about the cart on a treadmill when it was turned on, I didn’t anticipate the fan, and it brought to mind more questions. Was a fan used in all the other carts on treadmills that I’ve seen?

Speaking only for the videos JB and I have posted, there is only one that uses a fan. It's used with the cart sitting on a motionless level treadmill. The only reason I use a treadmill here is that it provides a suitable level surface. The fan is used to demonstrate the cart will self-start in a tail wind. In one of the other videos I pan the camera left and right to show there is no fan or other trickery involved.

What air speed did the fan produce, and what was the speed of the belt?

The fan produces surprisingly little air-flow. The belt was stationary.

spork: I truly wish you could have heard how hard and long I laughed reading the above. You are second only to John in inducing guffaws, and standing out in this crowd ain’t easy.

I'm proud to be in the presence of greatness. John's had me going pretty good a few times (with the wife rolling her eyes at my inane internet addiction).

Um, yeah. About 2500 posts ago I stated that the prop essentially added mass to the system, exhibited as thrust.

The prop is used to change the rate of momentum of the air. This is how thrust is produced. It does not add mass to the system.

I have yet to see anyone to address the issue of the increase in velocity being linear

With respect to what?

...or, as I suspect, oscillating rapidly about a point

Do you really want to hop on the crazy train with humber? Are you angling to have someone dedicate an 87 page thread to your confusion about basic physics? Is this spreading!? Do I need to wash my hands after making this post?

I'm not sure why, but I see it as "bouncing" off the air compressed behind the prop.

I'm not sure why either. But that's a fairly common misconception. And it is absolutely demonstrably wrong. We're still talking about the childish toy that I'm so fascinated with - right?

 

[spork]

I said: I've never blogged a single word in my life.

3bodyproblem said: Now that's a lie and you know it. Shameful.

I don't lie. If you're going to call me a liar you'd better be prepared to prove it. Show me where I've ever posted one word of blog.

Shameful? Damn right - it's shameful for you to make unfounded accusations. And it's shameful for you to call yourself "3bodyproblem" when you don't understand the most fundamental aspects of classical physics.


Dan, do we need to start a separate list, or can we just lump this lump in with humber?

 

[Christoph]

Christoph=schrøder=humber?

Christoph do this resonance also happens if the treadmill is 100000 km long?

If both the cart and the treadmill were proportionally scaled up in size, and it were still running at the same meters/second and the same rotational frequency, then most certainly it would have the same resonant effect on the cart. However, if only the treadmill was upsized and the cart remained small, the velocity of the tread would be enormous and the cart would never be able to achieve resonance with the moving tread. Also, the air around such a giant treadmill would have no direct correlation with the motion of the tread, just as the winds on the earth cannot be said to be directly correlated to the rotation of the earth. If they were, we would always be experiencing the same amount of wind from the same direction, and we obviously do not! With the wind around such a giant treadmill swirling incoherently, the cart again could never achieve resonance, just as a cart running on the surface of the earth, even directly along the equator, cannot achieve resonance with the earth. So, what I am saying is this: IF the “faster then treadmill” effect is due solely to the cart achieving resonance with the treadmill, and IF the cart cannot achieve the same resonance with the ground when off the treadmill, the cart cannot achieve “faster than the wind” whilst running on the surface of the earth.

 

[mender]

Almost the same. The cart is 'held in place' by the airmass. but the motion that you see is relative to the ground not windspeed. So the same as a very slight breeze with the cart on the ground?
The treadmill has nothing to do with windspeed. It is pointless to consider longer belts.

I take this as another recant of the "wind speed is stand still, in still air" statement.

Another correct statement! "You can say that the cart accelerates away from that ..." - yes, you're absolutely correct, I can say!

 

[Furcifer]

Adding a heavy propeller slows up the whole process of getting up to speed.

Who said anything about making the propeller heavier?

Mass exhibited as thrust? That sounds like one of humber's lines.

Thrust is the change of mass wrt to time.

I'll give it a go if you like. I have been testing my cart downstairs on my treadmill and have a pretty good idea how the cart works.

You need to measure the lift/drag ratio instaneously while the cart is on the treadmill. And you need a very small time interval between measurements. No small task.

 

[mender]

So, what I am saying is this: IF the “faster then treadmill” effect is due solely to the cart achieving resonance with the treadmill, and IF the cart cannot achieve the same resonance with the ground when off the treadmill, the cart cannot achieve “faster than the wind” whilst running on the surface of the earth.

Do you agree that the corollary must also be true, that if the "faster than treadmill" effect is NOT due to the cart achieving resonance with the treadmill, that the cart CAN achieve "faster than the wind" whilst running on the surface of the earth?

 

[semper]

Your words not mine, semper. I say that there is no need to provide a common separate frame. because all objects are in that frame, but if you like, may be viewed from different frames.

Mmm, but you haven't shown any ability to take these views, nor perform analysis using them. Have you heard of the Downwind Turn Myth?

Now semper, I wouldn't call humber uneducated OR stupid or any combination of those two. His on the spot erudition and word play is indicative of a widely read and complex person. His diversity of experience and familiarity with unique niches of knowledge are quite fascinating. It's his bizarre excursions off the beaten physics paths that have kept this thread bouncing around for 3000 posts, and his interpretations of what he reads and sees that would lead someone to doubt (or praise in the case of recursed moppet) humber's ability to understand classical physics.

Yes Mender, I think I agree, and so I do not call him uneducated or stupid, but many times what he says would concur with those peoples' ideas.

 

[Christoph]

Do you agree that the corollary must also be true, that if the "faster than treadmill" effect is NOT due to the cart achieving resonance wit the treadmill, that the cart CAN achieve "faster than the wind" whilst running on the surface of the earth.

That seems reasonable, IF you can show where the energy is coming from. A resonance can greatly multiply the energy delivered to a mechanical component in a resonant system and it can explain the cart going faster than the treadmill. If you discount the resonant effect, then you need to propose another source for the energy, especially in the down wind situation. The main problem with the down wind situation, as I see it is that no one has been able to explain where the energy is coming from.