DDW.mov

This is a vehicle built to travel dead downwind, faster than the wind itself! Seems impossible? It's not, I saw it first hand. In this video it topped out at 50 mph, in about 20 mph of wind.

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Science & Technology

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• DDW

[lykenth08]

If you use an axial turbine, means you can go in ANY direction =D that was my idea

[locouk]

So this can gather momentum in the dead wind zone? What pushes the prop round at that stage and beyond? Hamsters?

[9inchesofHATE]

The only way I could perceive this working is if you had a geared flywheel that would carry enough momentum to accelerate the cart through 0 apparent wind and then switch the pitch on the blades so it was as though you were going into a headwind... but even then drag would be an issue. I'm curious to see what performance you would get with a direct head on wind.

[betonmolenislol]

eat that solar races.

[planetofthescums]

Cart goes in the wind, you go in the cart, propeller is in the wind...

Does he put the brakes on the end, does the wind die, what happens?

[planetofthescums]

@axelerat3d How it initially moves forward the same as how it finishes moving forward. You have some choices on how you describe that but it must be able to work throughout the entire process.

The way it moves at 0.01 mph is the same as how it moves at 38 mph. Is the prop pushing the wind, is the wind pushing the cart, are the wheels driving the propeller... you have to be very careful how you describe what the cart is doing and I think, if indeed problems persist, this is where they lay.

[planetofthescums]

@axelerat3d I still don't see the point of it "tacking" that seems unecessary.

Just ignore friction and other things if people don't bring it up themselves; most people tend to ignore that stuff without mention.

Then, what exactly it claims to do, it claims to take energy from a volume of wind and use it to accelerate a cart to a high rate of speed.

So you have to explain next why this won't work with light particles reflecting on a solar propeller because nothing exceeds light speed. (jk)

[planetofthescums]

@axelerat3d I get you understand the basic concept of the cart. People, like myself, who don't understand the cart make confusing statements.

The other thing is, I don't understand the wind, I don't understand gears, and so on.

The best way to explain it is physically how the parts are constructed. That should be the basic starting point that would negate a lot of confusion.

I am just curious about the balancing act of the cart higher ends and that requires a larger background of information.

[axelerat3d]

@planetofthescums

Nobody is claiming that it is anything more special than it is. Its a brain teaser. If you think our explanations are bad why don't you summarize how you understood it. I am all ears for more intuitive ways to explain it. I have tried zillion and different people seem to get the light bulb going off from different clues.

it is counter intuitive - that is why it is a mind teaser. The creators of the cart in the video have credited several predecessors of the idea.

[planetofthescums]

So if the device travels faster than the wind while is deplenishes the wind and you measure the wind that's being deplenished. There are a lot of efforts that must be made to measure the device accurately.

At least I finally understand the concept behind the stupid thing.

Wikipedia had this to say: (feel free to answer any one of my questions) the ship is sailing the same speed of the wind so you throw a propeller in the water that runs a propeller in the air and you can gain speed.