Re: OT Here is an example of pseudo science.

[dennis]

What is that supposed to demonstrate? that if you pull the centre along it goes faster because of the gearing between the centre and the edge? that's all it does show.

[Rick Cavallaro]

I'll let one of the locals explain it to you.

[Clive George]

Yes, and that's all it does need to show.

So you agree that yes, I can have that drive mechanism, and it can be as simple as eg having a a 2:1 chain drive such that the wheels on the conveyor belt go half the speed of those on the road?

Now with that arrangement, what can you tell me about the forces the wheels/axles are exerting on a) the road, b) the conveyor belt and c) my little car? Relative magnitude and direction will do.

[Clive George]

Got it. No real need for the numbers, took me a while to get L/D = lift over drag, and publishing it as a jpg would have been friendlier, but still it works.

[Rick Cavallaro]

Sorry about that. As an aero guy I didn't even think to write that out. I should have.

Sorry about that too. .jpgs give you ugly artifacts on high contrast images. gifs just look better, but either one would work.

[ThinAirDesigns]

Me:

@dennis@home

Ok, this may be progress. It appears that you have no problem with "A" nor with "B", but you can't agree with "C" -- you do not agree that the slowing the wind provides enough energy to turn the prop.

Before I go on, can you confirm that I understand you correctly? Thanks

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember ThinAirDesigns saying something like:

Light dawns. If you'd mentioned pusher prop at the start...

My gut feeling is it would be heavily dependent on very low frictional losses in the transmission of whatever type. Permanent Magnet bearings? Air bearings need an input.

WD40?

[The Natural Philosopher]

Conceptually its easier to think of it like a air paddle steamer car

The wind blows the car along, which drives the paddles which move backwards against the wind. Therefore the paddle blades are never in still air when the car is travelling at windspeed. So they can still extract energy.

[Rick Cavallaro]

To go faster than the wind requires reasonably low losses. As you try to achieve multiples of wind speed the allowable losses become smaller at a ridiculous rate. We run in the area of about 3X wind speed. 5X would be a real challenge.

[Rick Cavallaro]

You're exactly right, but I'm sure that's more intuitive for some and less intuitive for others. On top of that, you have to describe how the forward moving paddles don't kill the whole deal. They need to retract or feather in some way.

[Clive George]

Not that I ever do similar things in other contexts...

Actually gif published as an image rather than a download would have been perfectly fine, but never mind, it all worked and I shouldn't be picky - you're the one putting in the time drawing pictures and explaining it all to the rest of us :-)

[Rick Cavallaro]

I'm not an expert on usenet. On a typical forum I'd post the .gif image. Can we post images here?

[Clive George]

Definitely not :-) This area of usenet is text-only, binaries are out.

I'd just stick it up on a photo sharing website (which is why I thought jpg on autopilot) - or if you've got your own site, there?

(in case of confusion, when I said image rather than download, I meant such that the link showed you the pic straight away rather than having to download - not image within the posting)

[Rick Cavallaro]

makes sense. This was the quick and dirty approach.

[The Natural Philosopher]

I'll put them in a housing.

[ThinAirDesigns]

@The Natural Philosopher >

I'd have to see a sketch of your idea, but I believe you may find that while a housing might protect them from the relative headwind, it doesn't keep them from having to 'churn' the air in the housing to a point of overall system failure.

Again, just a general comment as I'm not privy to your specific idea.

[dennis]

That is easy, nobody has argued against it. The arguments against have always been deflected onto something else in all the replies in case you had not noticed.

Like the one about the treadmill demonstrating the required effect.. it doesn't, all it shows is you can take power from the belt to drive a prop with enough thrust to power the cart faster than the belt. It doesn't show that you can extract energy from wind and use the same energy to go faster than that wind.

Even the main video doesn't actually show that, it doesn't even show they are going downwind, the wind vanes show the apparent wind and not the true wind so they could be going at an angle and the wind vanes would not show that.

What will that prove that has any relevance to going down wind faster than the wind? Is this just another deflection attempt?

[dennis]

I don't agree that you are slowing the real wind.

[ThinAirDesigns]

@Grimly Curmudgeon

I have no idea how I could have mentioned it any sooner than the very first sentence of my very first post on this thread -- which is what I did.

[ThinAirDesigns]

@dennis@home

So, you believe that a propeller *can* slow the real wind (you said "B" was true), you just don't believe that our propeller *IS* slowing down the real wind.

Is that correct?