Elroy Jetson said...

Play the ball not the man Spork.

I see again you have absolutely nothing to say about the extensive explanations and information I gave to you via link.

Soon, (just like last time when I gave you extensive detail and you complained I gave you none) you will be claiming that I never posted any explanations and that we are being intentionally coy and obtuse.

We have previously roped goats.

JB

spork said...

I've given at least a dozen different explanations that are absolutely valid and vary in mathematical detail so that anyone should be able to follow.

Still waiting....................

So to keep this thread on topic. You guys claim that you have built a wind powered vehicle that goes directly downwind faster than the wind. In all the years it took to research, build and try the machine you haven't thought to write down 2 paragraphs explaining how it works?

how can it be if the true wind is coming from the north .. the boat is heading south .. so the aparent wind is coming from the south .. because aparent wind comes directaly head on for anny moveing object ..
so the true wind from one direct and the aparent for the other directing ...... ??

I think I understand the basic principle now It does take a little while to figure it
as a lot is written about the high techo side and the building without explaining the basic concept to start with or if it was I missed it .
I see it as a thrust multiplier device The wind starts it rolling by pushing against
the cars surfaces the wheels turn and drive the prop which pushes back against the wind which drives the car faster which in turn drives the wheels which drives the prop faster etc etc until it is overcome by frictional losses and other inefficiencies and reaches its maximum potential At least thats how I see it
To achieve what they have has taken a lot of clever design work overcoming all the various obstacles

Spork and ThinAirD claim they have built a wind powered machine that goes directly downwind at 2.8 times the speed of the wind. They would like others to believe this claim.

I found this interesting and wanted a little more information on how it worked.

But neither of them has posted a single explanation (on one post) of how the machine works. It is now a certainty that they never will.

Their method of explaining to us the wonders of their machine is, firstly, to wait for a person to try and explain their machine for them, pick apart the persons post by telling them that are incorrect or giving little snippets of (mis) information. Secondly to cover for the fact that they haven't posted an explanation here they jump on the front foot with silly personal attacks.

30 posts later. We finally have a summarised answer to think about:

From the above youtube link

"Think of it as a loop that provides thrust to push the car downwind. This causes the wheels to turn which in turn helps to spin the propeller. It then catches more wind and so on."

Spork and ThinAirD will surely also agree that this is a good summarised answer. Surely...

the wheels turn and drive the prop which pushes back against the wind which drives the car faster...

Basically you've got it all right - with the exception of this part. There is no convergence of wind between the tailwind and the wind pushed back by the thrust. It's better to think of the tailwind as simply the moving airmass in which the cart is submersed. The prop is winding its way forward through that airmass - as the prop on an airplane would do whether it's going upwind, downwind, or in no wind.

Elroy Jetson said...

But neither of them has posted a single explanation (on one post) of how the machine works. It is now a certainty that they never will.

This is an absolute lie of course and the truth is backed up by the record of the thread.

My very first post on this thread (Posted 09/11/2010, 5:00am) includes links to complete and comprehensive treatment By MIT Professor Mark Drela.

Just a few posts later (Posted 10/11/2010, 1:33 am) I posted a link to one of the most extensive libraries of complete explanations on the internet.

JB

spork said...

the wheels turn and drive the prop which pushes back against the wind which drives the car faster...

Basically you've got it all right - with the exception of this part. There is no convergence of wind between the tailwind and the wind pushed back by the thrust. It's better to think of the tailwind as simply the moving airmass in which the cart is submersed. The prop is winding its way forward through that airmass - as the prop on an airplane would do whether it's going upwind, downwind, or in no wind.

Yes I can see that was not right
I imagine that at some point the pitch of the prop is reversed? And this would be when the car is travelling at something less than wind speed ? This changeover would rely on the cars momentum to carry it
through ?

If I may I would like to explain how it works in my simple terms. Please correct me if I am wrong.

The initial movement down wind is caused by wind resistance of the whole of the cart but mostly from the area of the fan blades.

If the fan was not mechanicaly connected to the axle and wheels and therefore freewheeling, it would spin in the opposite direction to what it does in the vid and would tend to climb up wind but due to wind and bearing frictional losses that is not possible.

Now when the fan is connected to the axle and wheels so that the fan can only spin in the opposite direction to which the wind wants to spin it we have set up a "dynamic??" which is harvested.

As the cart moves down wind, initially from wind resistance, the mechanicals drive the fan which makes it bite into the air mass which pulls the structure of the cart forward in the air mass.

Up to the point where the cart is travelling at wind speed it is still getting drive from the wind as a sail does.

At that point the mechanical advantage "the dynamic", which is a ratio between the axle RPM, fan RPM and the fan pitch, overcomes rolling resistance and friction losses and pulls the cart structure forward more in the air mass which in turn spins the fan faster which makes the cart move faster which makes the fan spin faster etc, etc, but not quite ad infinitum.

If there was no such thing as mechanical frictional losses or rolling resistance it would no doubt be very fast but not unlimited in speed.

If there was no such thing as air friction (let's call it wind resistance), it wouldn't do anything. So if mechanical losses were eliminated (wouldn't that be great) there must come a point where speed becomes limited by air friction.

"Blackbird" is quite rudimentary in construction if compared to "Greenbird" but the concept obviously works and has great potential.

If the foils (struts) that support the fan were rotateable like the foil on "Greenbird" they could be spread out to act as sails to assist getting up to wind speed and then tweaked inwards a little at speed to give some extra thrust by creating some vortex or lift.

Also a variable pitch on the fan may give more speed once a certain velocity is reached.

I think the project is fantastic and very much ripe for a development sponsor. Richard Jenkins got one and he has given you guys the thumbs up. Maybe the Ecotricity guys would be interested.

Good Luck with it guys.

cisco said...

If I may I would like to explain how it works in my simple terms. Please correct me if I am wrong.

The initial movement down wind is caused by wind resistance of the whole of the cart but mostly from the area of the fan blades.

So far, so good.

If the fan was not mechanicaly connected to the axle and wheels and therefore freewheeling, it would spin in the opposite direction to what it does in the vid...

Still good...

... and would tend to climb up wind

Nope. It would spin in the opposite direction, but would still get blown in the direction of the wind - with considerably more force than if it were not spinning. This mode would be like a helicopter in autorotation.

Now when the fan is connected to the axle and wheels so that the fan can only spin in the opposite direction to which the wind wants to spin it we have set up a "dynamic??" which is harvested.

I don't think I'd say "we set up a dynamic", but still on the right track.

As the cart moves down wind, initially from wind resistance, the mechanicals drive the fan which makes it bite into the air mass which pulls the structure of the cart forward in the air mass.

PRECISELY!

Up to the point where the cart is travelling at wind speed it is still getting drive from the wind as a sail does.

Yes, but it's also getting thrust from the prop. There's no hard-edged changeover point.

At that point the mechanical advantage "the dynamic", which is a ratio between the axle RPM, fan RPM and the fan pitch, overcomes rolling resistance and friction losses and pulls the cart structure forward more in the air mass which in turn spins the fan faster which makes the cart move faster which makes the fan spin faster etc, etc, but not quite ad infinitum.

Sort of. The real "mechanical advantage" takes advantage of the fact that the cart is moving faster over the ground than it is through the air - and can thus harness more energy with the wheels than is needed at the prop.

"Blackbird" is quite rudimentary in construction if compared to "Greenbird"...

Hey - wait a minute there!

If the foils (struts) that support the fan were rotateable like the foil on "Greenbird" they could be spread out to act as sails to assist getting up to wind speed...

Sure - why not.

...and then tweaked inwards a little at speed to give some extra thrust by creating some vortex or lift.

Nope.

I think the project is fantastic and very much ripe for a development sponsor. Richard Jenkins got one and he has given you guys the thumbs up. Maybe the Ecotricity guys would be interested.

We're very happy with Joby and Google

One thing I do know for sure Cisco is that your answer is basically right, except..................................................(Spork and ThinAirD will fill in the rest here)

Edit: Beaten to it by 2 minutes

Elroy Jetson said...
[What I meant was. You haven't provided an explanation on one post that explains the device or system (right here, not via links) -

I just love this -- the pathetic excuse for your asinine position is that my explanations involve clicking on a link, as if a link to a complete and valid explanation isn't offering a complete and valid explanation.

Click on the link and you might learn something (jk)

You're a hoot.

JB

To the "Blackbird Team" there is a positive side to this thread, your machine has been exposed to the world a bit more....

And aren't you glad you didn't have to explain [in the invention stage] how electricity, television, mobile phones or even nuclear fusion works to sceptics

I have found it very interesting and thanks for your explanations I think I have finally come to grips with it