Author Topic: Directorly Downwind Faster than the Wind (Read 149197 times)

BEP · « **Reply #90 on:** April 07, 2010, 01:03:08 PM »

Quote from: Cloxxki on April 07, 2010, 09:08:31 AM

Do you guys actually think that the wind is not needed to go fast down level ground? Free energy everywhere, you just need to want to tap it? Right?

No. For this or anything to work there must be a difference of potential, a source of usable energy. In this case it is the wind. I think this cart is analogous to a step-up transformer. There is no energy gain. There is only gain in velocity. The prop needs to push against something moving faster than the ground.

Quote

If there is any free energy to be had, it's going to have tpo be in conjuction with gravity.

Last time I was on the salt flats it was pretty flat. Gravity could be made part of this but what goes down looses going up, unless there is enough wind.

ramset · « **Reply #91 on:** April 07, 2010, 01:59:30 PM »

Clo
I have to say ,your gravity "angle" in all this seems "plausible"

I am quite sure that big brain of yours will figure a way to use this

"effect" towards a better understanding of what can be done here.

Listening to you fellas bang this around, is helping to understand whats going on here!

Thanks
Chet
PS
Besides it might help make my sail boat go faster

As Bep [or any sailor] knows ,this is always important!

BEP · « **Reply #92 on:** April 07, 2010, 02:44:19 PM »

Quote from: ramset on April 07, 2010, 01:59:30 PM

PS
Besides it might help make my sail boat go faster
As Bep [or any sailor] knows ,this is always important!

Aye! Me Bucko! Not much more fun than jumping a barge wake while under tack with a sloop and 3/4 of your keel showing! 2X wind speed could mean that jump could have been at 50 knots. With a huge prop spinning instead of taught mainsail and jib, it could be an ugly result.

Cloxxki · « **Reply #93 on:** April 07, 2010, 05:05:14 PM »

I wasn't saying THIS CART is getting its gain from going downhill, I'm not a debunker, I'm a believer.

@ramset
My brain may be volumous, but most empty, untrained and uncoordinated.
Should it be possible, in a simple setup just like DDW, maybe slightly adjusted gearing and prop style, to beat gravity, this would be just like creating your own wind. Or, OU. Setup could be mounted on a wheel of furtune kind of setup, and just mill away. For this to happen, the energy taken from the wheels of the "cart", should somehow bring a gain when converted to prop trust. this has "too good to be true" all over it, but I like it as a brain teaser.

Although gravity doesn't give a back draft when you surpass it, it also doesn't offer anything to press off against, like tailwind does.

It seems, as long as high-tech, efficient system are used, any vehicle used in the outdoors, could benefit from a wind prop to be engaged with its water prop or wheels when appropriate, be it roughtly downwind or upwind. More surface, more power, so mount as many on the sailboat as fit!

Cloxxki · « **Reply #94 on:** April 07, 2010, 05:27:55 PM »

What about a tailwind powered hovercraft. Could it be done?

Even better than a catamaran would be an aquafoil type craft. Almost only the prop in the water, to turn the wind prop on top. An ground effect hull might offer nicer lift even than an hydrofoil, lift for Watts of resistance?

ramset · « **Reply #95 on:** April 08, 2010, 12:59:36 PM »

Clo
Well one thing is for sure.
Something very cool is going on with this.

And that setup is doing work, beyond what is expected !
Way beyond!

I don't understand it [yet].
But I like it !

Chet
PS
Clo
I don't know if its good or bad ?
but I understand "most" of what you say!
I'm quite sure you are going to come up with something
that I will just have to try!

Remember "dirty air" [prop wash]
every prop needs to be in clean air!

BEP · « **Reply #96 on:** April 08, 2010, 01:09:20 PM »

Quote from: Cloxxki on April 07, 2010, 05:27:55 PM

What about a tailwind powered hovercraft. Could it be done?

Hovercraft... These are a passion of mine. That would be great.
The way I understand this, the craft would need one or more wheels on the ground and couldn't exceed much more than 2x wind speed. Using ground-effect a lot of lift surface area would be needed.

Interesting thought.

Cloxxki · « **Reply #97 on:** April 08, 2010, 10:07:35 PM »

Quote from: BEP on April 08, 2010, 01:09:20 PM

Hovercraft... These are a passion of mine. That would be great.
The way I understand this, the craft would need one or more wheels on the ground and couldn't exceed much more than 2x wind speed. Using ground-effect a lot of lift surface area would be needed.

Interesting thought.

I would be interested to know how much power of a hovercraft's engines (I never saw one in person) is required to properly fill the air cushion, and create the frictionless interface. I suppose surface and weight (psi?) would be a main factor? Still, a hovercraft is supposed to be an efficient (for payload, fuel consumption and speed) form of water transport, correct?

I have a bit of an obsession for ground effect. I want a human powered ground effect wing, that is faster and more manoeuvrable than the existing Channel-crossing biplane type fly-zilla's. It's all about surface to weight I suppose here also. Thus, a matter of efficient engineering.
Unfortunately with an airborne craft, it's hard to drive the prop with a hard fix on the ground speed, to gear it over the apparent headwind, and get forward thrust.

@Ramset : if this stuff fascinates you, and you are not shy for a build project, this seems like great fun. It can always entertain friends. Just keep some balloon on hand to make speed comparisons. Hey, you might earn back your time in bet wins!
Don't expect to build a cart that will ride by itself day and night, as really, it needs wind, preferably tail wind.

ramset · « **Reply #98 on:** April 08, 2010, 11:36:12 PM »

Clo
Hover craft is a fuel pig!

Ground effect!
Now your talkin, get a plane off the ground [or a boat off the water].
Cut back the throttle 70% in ground effect!
Yes a passion of mine also!

Chet

Cloxxki · « **Reply #99 on:** April 09, 2010, 12:27:28 AM »

Quote from: ramset on April 08, 2010, 11:36:12 PM

Clo
Hover craft is a fuel pig!

Ground effect!
Now your talkin, get a plane off the ground [or a boat off the water].
Cut back the throttle 70% in ground effect!
Yes a passion of mine also!

Chet

Thanks for the heads-up Chet, fuel pigness reduces hovercrafts back to toys for me :-)
It bugs me that the firm surface-craft traction is required to leverage the power of the tailwind. What's a ground effect wing worth when it drags a pizza cutter to power the prop that keeps it flying?

I just thought that a ground effect wing could feature 2 opposing airfoil chimneys, to possibly negate the lateral drifting, and need for a draggy keel. For the aerodynamics lover that would a fun project, build a wing from styrofoam (sp) or paper mash, and put paper airfoils on it. Make the design adjustable to find a sweet spot. RC the controls. It might work, or it might not, I am not well read into the wind scene.

I am still strugling with my own mind teaser. Can gravity's pull be used to get the part rolling, and can the turning wheel be used to drive an over-geared prop, to give nett thrust that sends the cart accelerating past gravity-only power, in still wind? Or do the wheel feel a braking force (to power the over-geared prop) that surpasses the thrust a prop can offer at any given speed? If a gain can be had, that make it a perpetuum mobile for me. Use wind drag (reversed in the prop) as a power source. All my life I've been thinking about how drag could be reversed. Might this be it? The aeolus racers fought against the wind inching straight into it, not even trying to use it to triple their speed downwind. Now, the signs are that 4x the wind speed may soon be achieved by a prop cart. So, could "tail wind" be replaced by "gravity" as power source? A gravity power generator that relies on the viscosity of air? A man can dream, right? Certainly on here.

Anyone know how good aerodynamic modelling programs are lately? In the relative (to aerospace) low wind speeds that wind powered carts encounter, some extreme prop layouts might be tried to maximize thrust.

Cloxxki · « **Reply #100 on:** April 19, 2010, 06:01:36 PM »

They made it faster and prettier:

http://www.fasterthanthewind.org/

Pirate88179 · « **Reply #101 on:** April 19, 2010, 10:17:07 PM »

That is really amazing! That new craft should really fly out there. Very interesting reading.

Bill

Cloxxki · « **Reply #102 on:** April 19, 2010, 11:25:34 PM »

Quote from: Pirate88179 on April 19, 2010, 10:17:07 PM

That is really amazing! That new craft should really fly out there. Very interesting reading.

Bill

Well, they rounded some edges, and did good to the sponsors, but they also added roughly 50lb acording to Spork. I am not sure the amount of drag previously generated at ~30mph apparent headwind amounted to all that much, in comparison to the power extracted from the wind with that, what, 12 foot propellor? It may help a couple mph on a good long run. And the weight might aid in being more stable in apparent headwind bursts.

The unpimped cart already performed above anyone's expectations, I suppose, being so basic. One rotor, no aero body work.

ramset · « **Reply #103 on:** April 20, 2010, 01:23:17 PM »

Clo
Thanks for keeping us posted!
This still "pains the brain" for me!

Seems like other techs could "evolve" from here?

Chet

Cloxxki · « **Reply #104 on:** April 20, 2010, 10:19:36 PM »

Quote from: ramset on April 20, 2010, 01:23:17 PM

Clo
Thanks for keeping us posted!
This still "pains the brain" for me!

Seems like other techs could "evolve" from here?

Chet

Oh I'm just an intrigued groupie, reading all I sensibly can on the subject. Understanding, I do far from all.
I can totally see alternative prop setups be even more efficient. Boats can use principle too.
But in terms of practicality, it doesn't do much more than offer a (small) auxiliary power source on existing vehicles. You're rolling down a highway, GPS system knows the way. Wind sensors know what's going on. In appropriate moments, the will come from out of it's casing (like a double roof), and via a clutch to the drive shaft, be brought up to desired speed by, effectively, the wheels or engine. It would not do much, but when guided by a smart computer, it could reduce fuel consumption some. And hey, a prop on your car makes all kinds of sense anyway. It only rides 1 hour per day on average, the rest it's standing in the wind.
We need to harness all the free energy we can. If you see a car, or a building without turbine, energy is being wasted right there.

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Author Topic: Directorly Downwind Faster than the Wind (Read 149197 times)

BEP

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ramset

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Cloxxki

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