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Clarification

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Ventomobile and Greenbird do not appear to be "wind powered electric vehicles". Instead, they are more modern and sophisticated versions of land sailing vehicles. The wind propels these vehicles directly through mechanical means, rather than by generating electricity that would propel the vehicle by electric motors. The Mercedes "Formula Zero" proposes to use a combination of stored battery power and electricity from solar cells to power the electric motor, and the propulsion is then supplemented by a high-tech sail. Jim Heaphy (talk) 02:59, 3 January 2010 (UTC)[reply]

The article also fails, quite disgracefully, to mention Simon Stevin, or provide a link to the article about Land yachts. —Preceding unsigned comment added by 81.98.50.97 (talk) 23:35, 14 July 2010 (UTC)[reply]

Add a section on the Blackbird?

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I wonder if I could talk someone into adding a section on the Blackbird. This vehicle set a record in 2010 by going directly downwind at 2.8X wind speed, and after modification set a new record by going directly upwind at 2.1X wind speed. The records were both ratified by the North American Land Sailing Association (NALSA), and the reports and data can be found at www.nalsa.org. There are lots of photos, video, articles, etc. on this project/vehicle. Spork33 (talk) 06:36, 1 August 2012 (UTC)[reply]

checkYDone.GliderMaven (talk) 18:25, 19 September 2013 (UTC)[reply]

Scope—Land only?

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Since Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913 defines "vehicle" in the ordinary sense as: "That in or on which any person or thing is, or may be, carried, as a coach, carriage, wagon, cart, car, sleigh, bicycle, etc.; a means of conveyance; specifically, a means of conveyance upon land" and since there are other articles on wind-powered vessels, ice boats and other conveyances on water, which would better be referred to in "See also", why is this article not appropriately limited to items that roll on wheels (to exclude sliders, such as sledges, travois, toboggans, etc.)? There doesn't seem to be much added value to the reader in the "Water" or "Ice" sections, anyhow. User:HopsonRoad 22:01, 26 January 2017 (UTC)[reply]

No, a vehicle is any conveyance, there's also air vehicle, space vehicle's etc. Article's aren't about words like 'vehicle', but modern usage is far wider anyway.GliderMaven (talk) 00:19, 27 January 2017 (UTC)[reply]
That may be semantically true, GliderMaven, but we editors get to define the scope of articles to be useful to the readers. All the interesting stuff here is about land vehicles, which one gets to after passing through large blank spaces about sailboats and sailing ships that could be handled with a "See also" at the beginning—likewise, for ice boats.
I feel that the reader, who is drawn to this title, isn't so much interested in schooners, barques, brigs, barkentines, brigantines or sloops, as they might be in the cool land vehicle concepts. If they wanted to know about sailing vessels, they would know where to turn—it doesn't require this article to guide them there.
In the current lead "seafaring vehicles" is an immediately jarring construct—I've never heard someone use that turn of phrase, except for an amphibious vehicle.
The lead might read something like this:
Wind-powered vehicles derive their power from sails, kites or rotors and ride on wheels, which may be propelled by a wind-powered rotor. Rotor-powered examples have demonstrated ground speeds that exceed that of the wind, both directly into the wind and directly downwind by transferring power through a drive train between the rotor and the wheels. Other wind-powered conveyances include sailing vessels and ice boats, which are beyond the scope of this article.
Cheers, User:HopsonRoad 13:09, 27 January 2017 (UTC)[reply]
We could have the discussion, but I would expect that the article probably wouldn't end up being on wind-powered ground vehicles only. Incidentally, did you know there's at least one type of wind-powered air vehicle, and other theoretical types as well.GliderMaven (talk) 16:13, 27 January 2017 (UTC)[reply]
Thanks for this reply, GliderMaven. I'm picturing other relevant topics to be connected by linking. I assume that you're not referring to a sailplane, which you clearly are very familiar with. Tell me more, if you would—perhaps at User talk:HopsonRoad. Cheers, User:HopsonRoad 20:00, 27 January 2017 (UTC)[reply]
The article scope, structure and content is ambiguous. A solution could be to make an overview article like Wing configuration and then move detailed content to separate articles, like Wind car or something. TGCP (talk) 16:08, 27 January 2017 (UTC)[reply]
Thanks for the suggestion, TGCP. I note that Wing configuration has substantive content throughout, whereas this one does not (as you indicate). There is plenty of taxonomy in Sailing and Ship articles, e.g. Sail plan, which is similar to wing configuration. It seems to me that wind-powered land conveyances need a taxonomic starting point and that would be appropriate for this article. Cheers, User:HopsonRoad 16:19, 27 January 2017 (UTC)[reply]
It seems to me that, a one hundred year out-of-date dictionary not withstanding, that we're not going to do that.GliderMaven (talk) 20:20, 27 January 2017 (UTC)[reply]
GliderMaven, here are some definitions of "vehicle":
Most of these have terrestrial applications as their primary sense. None of these definitions mention watercraft.
Cheers, User:HopsonRoad 04:38, 28 January 2017 (UTC)[reply]
Let's give other editors an opportunity to inform this conversation. As I said, above, we have the opportunity to define scope in a reader-friendly manner. Sincerely, User:HopsonRoad 20:42, 27 January 2017 (UTC)[reply]

BTW, GliderMaven, how does it make sense to have the heading of Wind-powered vehicle#Wind-powered mechanical vehicles contain "Water" and "Ice" subsections, especially given the introductory paragraph? Should we regard an ordinary sailing vessel or ice boat to be a "mechanical vehicle"? It seems to me, that a mechanical vehicle would refer to something with rotating parts in the drive train. In that case, the two headings might be "Sail-driven" and "Rotor-driven". Sincerely, User:HopsonRoad 21:05, 27 January 2017 (UTC)[reply]

Scope alternatives

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Resolved
 – In the following discussion, the consensus was for Option 3.

In our discussions of scope, above, GliderMaven and I haven't achieved consensus. It may be because neither of us has adequately defined what the scope alternatives are and chosen among them. My main issue is for the article title to reflect the intended scope. So here is a layout of alternatives, as I see them (Please comment in the Recommendations section, below):

Option #1: Status Quo

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  • Title: "Wind-powered vehicle"
  • Lead sentence: "Wind-powered vehicles have traditionally been associated with seafaring vehicles that, until the advent of steam engines, relied primarily upon winds which were used to drive the sails of such vehicles to their destinations. In the Western world, such sail-based wind propulsion on water persists in the modern day within primarily leisurely activities, such as sailing boats, sailing ships, yachting, and windsurfing. A special case is ice yachting on ice-covered water."

Sections:

  • Wind-powered mechanical vehicles
    • Water
      • Sailboats (generic examples)
      • Sailing ships (generic examples)
    • Land
      • (Five specific examples)
    • Ice (no sub-examples)

Problems:

  • The title appears to be about vehicles in the ordinary sense—traveling on land (there being no wind in space).
  • The lead introduces the awkward idea that "vehicles" includes vessels, something not supported by normal definitions of the word.
  • The introductory sentence of the main section is about "mechanical" vehicles, yet we see sections on sailing vessels and ice boats below it.
  • The water section has generic examples, the land section has five specific examples and the ice section contains no examples.
  • Doesn't highlight propulsive mechanisms, e.g. sail, rotor, kite, etc.

Option #2: Expand scope

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  • Title: "Wind-powered travel"
  • Lead sentence: "Wind-powered travel encompasses sailing craft—which remain the only practical means of point-to-point travel—wind-powered vehicles, ice boats, sail planes and balloons."

Sections:

  • Water craft
    • Sail-powered
    • Rotor-powered
    • Kite-powered
  • Vehicles
    • Sail-powered
    • Rotor-powered
    • Kite-powered
  • Ice boats
  • Aircraft
    • Balloons
    • Sail planes

Option #3: Limit scope

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  • Title: "Wind-powered vehicle"
  • Lead sentence: "Wind-powered vehicles derive their power from sails, kites or rotors and ride on wheels or runners, which may be propelled by a wind-powered rotor. Such vehicles are often capable of speeds that exceed that of the wind. Rotor-powered examples have demonstrated ground speeds that exceed that of the wind, both directly into the wind and directly downwind by transferring power through a drive train between the rotor and the wheels. Other wind-powered conveyances include sailing vessels and ice boats that travel on water, balloons and sailplanes that travel in the air, all of which are beyond the scope of this article."

Sections:

  • Sail-powered
    • Theory
    • Sand yachts
    • Ice boats
  • Kite-powered
    • Theory
    • Kite buggy
    • Kite board
  • Rotor-powered
    • Theory
    • Race-course vehicles
    • Straight-line vehicles

Perhaps editors can choose among the scopes above and articulate their reasons for the merits of their choice, below, in Recommendations. Sincerely, User:HopsonRoad 12:56, 28 January 2017 (UTC)[reply]

Vote for option #1, surface is better scope than technology since tech stuff can be reached on Wind propulsion.--Neurorebel (talk) 18:31, 6 February 2018 (UTC)[reply]

Recommendations

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  • Option 3 is the best, but 'wind-powered travel' is the wrong title; it would imply and include things like electric trains/electric cars powered by fixed wind turbines. 'Wind-powered vehicle' potentially could include that, but doesn't suggest it nearly so strongly.GliderMaven (talk) 16:25, 28 January 2017 (UTC)[reply]
Thank you for this reply, GliderMaven, I was suggesting a separate overview article (Option #2), as well. Is that something that you recommend? It can be made clear that vehicles that receive electricity through the grid are not in the scope of "wind-powered", even though the grid may have wind power in the mix. Cheers, User:HopsonRoad 17:26, 28 January 2017 (UTC)[reply]
  • Late comment: restricting it to wheels and blades is an absolutely and completely pointless restriction, the maths is the same for waterborne vehicles, and waterborne vehicles can use propellers just the same, or centerboards. You're making a false distinction.GliderMaven (talk) 17:01, 1 March 2017 (UTC)[reply]

Sandbox for revision

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I have started a sandbox for revision of this article, here. As it develops, you can post your comment, below. User:HopsonRoad 17:45, 28 January 2017 (UTC)[reply]

Comments

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Note that I've eliminated reference to the Mercedes-Benz Formula Zero, because—despite appearances—it is a solar vehicle, not a wind-powered vehicle. User:HopsonRoad 12:48, 29 January 2017 (UTC)[reply]

Expansion of theory section

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@GliderMaven: I notice that you have tagged the "Theory" section as needing further expansion. Any suggestions about what's needed to help guide your fellow editors? Cheers, HopsonRoad (talk) 23:45, 31 July 2018 (UTC)[reply]

An actual explanation of the theory, like the one you cavalierly deleted from another page. GliderMaven (talk) 00:42, 1 August 2018 (UTC)[reply]
Please be so kind to point to the edit in question, so that we can discuss the substance of that explanation that you feel is missing here. Sincerely, HopsonRoad (talk) 02:38, 1 August 2018 (UTC)[reply]
The sections two frames of reference are interesting, but the section seems fairly complete and sensible to me. @GliderMaven: perhaps you can point out how it is deficient? - Ahunt (talk) 11:47, 1 August 2018 (UTC)[reply]

Who is driving whom?

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In regard to the rotor driven vehicles, I (being a mechanical engineer) strongly insist, that who drives whom does not depend on the reference frame. It is true, that from the point of view of a bystander the Earth is accelerated and the air is decelerated, while from the point of view of a baloonist the Earth is decelerated and the air is accelerated. But whether the rotor acts as a wind turbine or as a propeller depends only on the relative speed of the vehicle to the air. If the vehicle travels faster than the tailwind, there's no way the rotor can drive the wheels. Rather the wheels drive the rotor, who pushes/pulls the vehicle. Эйхер (talk) 20:09, 23 June 2021 (UTC)[reply]

The article explains that propelling the vehicle depends on two masses moving with respect to one another—in this case air and the Earth's surface. One part of the vehicle, the rotor, connects with the air; another part, the wheels, connect with the surface. Choosing a frame of reference merely provides a point of view in this process, not a change of motive source. If you feel that the explanation is unclear in the article, you can propose better text, here. Cheers, HopsonRoad (talk) 20:28, 23 June 2021 (UTC)[reply]
I understand, of course, that the relative motion of two masses is the ultimate source of power for any wind driven vehicle. But the point is how exactly this is done.
The article states:
"As seen from the vantage point of the earth (e.g. by a spectator), the rotor (acting like a wind turbine) decelerates the air and drives the wheels against the earth, which it accelerates imperceptibly."
That's nothing but nonsense.
The net power required for any kind of propulsor (be it a wheel, a screw propeller, a fan, or a thermodynamic propulsor like a ramjet or a rocket engine) to propel a vehicle depends solely on the velocity of the propulsor relative to the reaction medium and is completely independent from the reference frame. For example, the engine power, required to drive a car, by means of wheels, or an aircraft, by means of a screw propeller, self evidently, does not depend on the reference frame.
For a vehicle, travelling downwind faster than wind, the velocity of the rotor relative to the air (its reaction medium) is smaller than the velocity of the wheels relative to the Earth (who serves them as a reaction medium). Therefore the power, required to propel the vehicle by the rotor (or, conversely, the power, that could be extracted by the rotor from the relative motion of the air) is smaller than the power, required to propel the vehicle by the wheels (or conversely, the power that could be extracted by the wheels from the relative motion of the Earth).
Therefore, the law of conservation of energy precludes propelling a vehicle, travelling downwind faster than wind, by wheels driven by a wind turbine.
But it is fairly possible (and actually done) to propel such a vehicle by means of an airscrew propeller, driven by wheels. Эйхер (talk) 10:17, 24 June 2021 (UTC)[reply]
Thank you for engaging here, Эйхер. In Wikipedia, we paraphrase reliable sources. In this discussion page we should be debating whether this has been done correctly, not whether what is stated comports with our individual analyses.
That said, your analysis above appears to conflate power derived from a fuel source with that derived from the differential movement of masses—atmosphere and earth. You speak of the velocity of the rotor in contact with the air, compared to the velocity of the wheel in contact with the ground. There is no requirement for the ratio to be one-to-one. It appears that you may also be conflating the forward velocity of the rotor, as a whole, with the rotational velocity of each rotor blade, which varies from hub to tip. It is that rotational velocity that either harvests or imparts (depending on frame of reference) power from the two moving masses. Cheers, HopsonRoad (talk) 15:24, 25 June 2021 (UTC)[reply]
I think that the point you are trying to make is illustrated by what happens when a wind-powered vehicle is going downwind at the same speed as the wind, itself, when a pinwheel would stop turning in the wind and a tell-tale would droop. At that speed the rotating airfoils of the rotors still maintain an angle of attack to (harvest/impart) power. The question arises whether there is a change in available power with speed and direction of travel of vehicle. With sails there would be, because their ability to develop lift is limited by a mast affixed to the sailing craft. With rotors there appears not to be, thanks to their being linked to the wheels. Cheers, HopsonRoad (talk) 18:11, 25 June 2021 (UTC)[reply]
Well, let's see what the reliable sources say. Here are quotations from the source cited in the article - Gaunaa, Mac; Øye, Stig; Mikkelsen, Robert (2009), "Theory and Design of Flow Driven Vehicles Using Rotors for Energy Conversion" (PDF), Proceedings EWEC 2009, Marseille{{citation}}: CS1 maint: location missing publisher (link).
In the section 1 ("Introduction") the authors say (underlining is mine):
In the section 2 ("Theory"), subsection 2.1 ("General energy conversion concept") they put it expicitly (italics are by the authors, underlining is mine):
Further in the section 4 ("Conclusions") they state (underlining is mine):
Эйхер (talk) 14:59, 26 June 2021 (UTC)[reply]
Thanks for your response, Эйхер. It's not only theoretically possible to go directly upwind and downwind faster than the windspeed, it's been demonstrated with Blackbird (land yacht). I feel that the concern you had with the article content was with the question of frame of reference. A description included in the cited reference. It took me some time to appreciate the usefulness of that description, which arose from an email correspondence with the MIT professor, Mark Drela, whose work is also cited in the theory section. Finally the light went off in my brain! What you point out, above, is that a rotor-powered vehicle goes through a lull in power generation, headed downwind, as the vehicle speed matches the wind speed, and would have to accelerate past that speed, using power harvested at a lower vehicle speed. Cheers, HopsonRoad (talk) 15:22, 26 June 2021 (UTC)[reply]
I know that going directly upwind as well as going directly downwind faster than wind is possible and was demonstrated practically. I'm not much concerned with passing through the lull point - it might be done easily with an ordinary flywheel. What I am concerned with, is that the theoretical explanation given in this Wikipedia article (especially for the downwind case) is nonsense that contradicts both physics and the reliable sources that are cited for it's support. So I'm going to amend the "Theory" section in accordance with the reliable sources as soon as I recover from the tooth extraction. Эйхер (talk) 16:08, 26 June 2021 (UTC)[reply]

I'll look forward to seeing what you write. In the meantime, here's wishing you a speedy recovery! Cheers, HopsonRoad (talk) 16:42, 26 June 2021 (UTC)[reply]

Latest tweaks

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Thank you for your efforts to improve this section, Эйхер! Together, we can get a good result. Rather than directly revert some of your changes, I'll make the following recommendations:

  • "A vehicle with a bladed rotor mechanically connected to the wheels can theoretically go at a speed faster than that of the wind." An important qualification, because actual examples may not be able to do so!
  • "Relative to the vehicle, both the air and the ground are passing backwards. However, traveling upwind, the air is coming at the vehicle faster than the ground, whereas traveling downwind faster than the wind speed, the air is coming at the vehicle more slowly than the ground." Because typically, people ride in vehicles. Vehicle don't generally ride, they travel, unless they "ride high (or low)". To avoid using the same verb, it's fine to have the air and ground passing by.
  • "How fast a given wind speed can propel a vehicle in either direction is limited only by the efficiency of the turbine blades, losses in the drive train, and aerodynamic drag on the vehicle's hull." Aerodynamic drag doesn't just occur on the "hull". Furthermore, "hull" isn't as idiomatic a term as "body" for a land vehicle.

Cheers, HopsonRoad (talk) 18:45, 1 July 2021 (UTC)[reply]

  • Of course, not every vechicle that have a rotor and wheels can go at a speed faster than wind, as well as not every crappy thing having wings and an engine can fly. But one doesn't say "An airplane can theoretically fly". It would mean, that no airplane have been tested in flight yet. It's what should be written in encylopedias before Dec.17, 1903. Perhaps, You mean "can, if properly designed"? Эйхер (talk) 19:34, 1 July 2021 (UTC)[reply]
  • It is very important, that the drag of the rotor (which occurs only in the case of travelling upwind, when the rotor acts as a wind turbine) does not limit the speed of the vehicle. Only the drag that occurs at the parts of the vehicle other than the rotor does. Эйхер (talk) 19:34, 1 July 2021 (UTC)[reply]
Thanks for these responses,Эйхер. Here are my responses:
  • I would say that all true airplanes can fly, whereas only some rotor-driven vehicles can exceed the speed of the wind. I recommend, "can be designed to...".
  • I concur substantially about the rotor, although we know that wings and propellors generate drag, while generating lift in their respective directions of travel. Struts, fairings, wheels, etc. are part of the totality of drag and are not part of the "hull", a term that's used mainly for tanks in English vehicle terminology. The rotor's drag occurs in an orthogonal plane to the motion of the vehicle, but still resists forward motion, owing to the reduction in power generated or power imparted due to drag. So, I stlll recommend "drag on the vehicle."
Cheers, HopsonRoad (talk) 21:13, 1 July 2021 (UTC)[reply]
  • When a flow drives a turbine, drag force is incurred to the turbine in the direction of the flow. If the turbine is 100% efficient, the power harvested by the turbine is the drag force times the speed of the flow (N=D*V). Thus this drag is but the price You have to pay for the power You takes from the flow. I would call it "productive drag". By selling the power You've bought from the flow to another (slower) medium, You can acquire a propulsive force. Therefore the amount of this kind of drag depends on how much propulsive force You want to have. The more You pay the more You buy. The more You buy the more You can sell. If You don't need much power, You can adjust the drag of the turbine by adjusting the pitch of the blades. If You choose to have more power, You will have more drag on the turbine but You also can have more propulsive force to offset the drag (i. e. You will have net profit by buying the power for a lower price and selling it for a higher price). Unlike this, the drag of the hull, of the struts, of the wheels etc. does not give You power and isn't adjustable. In aeronautics the like kinds of drag are commonly called "parasitic drag". It it is proportional to the square of the speed of the flow. Therefore, this kind of drag limits the speed attainable by the vehicle (see Ganuaa et Al). Эйхер (talk) 07:00, 2 July 2021 (UTC)[reply]

Thanks, Эйхер. I am familiar with parasitic drag and concur with what you say. Your mention of other elements of the vehicle that contribute to such drag, apart from the body, hull or fuselage, suggests that it's appropriate for me to generalize beyond "hull" to say, "drag on the vehicle". Cheers, HopsonRoad (talk) 13:20, 2 July 2021 (UTC)[reply]

I strongly believe that it is crucial in this case to separate the drag of the turbine from the drag of the rest of the vehicle, because it is a common (though wrong, of course) objection against such a vehicle, that the drag, inevitably arising from the process of power harvesting, would prevent the vehicle from motion. In fact, however, in the absence of other sources of drag, no amount of drag on the part of a 100% efficient turbine can prevent the vehicle from attaining any desired speed, however great (see Ganuaa et Al.). Эйхер (talk) 15:45, 3 July 2021 (UTC)[reply]
I concur, Эйхер. Don't we have it covered by "...is limited only by the efficiency of the turbine blades, ...."? Cheers, HopsonRoad (talk) 18:01, 3 July 2021 (UTC)[reply]
Эйхер, I feel that it's unnecessary to include "(i. e. drag not directly associated with power harvesting)", because that's what the blue link is for. Including it also suggests that we need to explain parenthetically the other elements in the sentence, which would make it cumbersome. I'm checking with you, before I remove it. Cheers, HopsonRoad (talk) 20:41, 3 July 2021 (UTC)[reply]
HopsonRoad,
  1. The definition in the article Parasitic drag formally doesn't specially exclude the drag of a turbine, though a knowledgeable reader could understand that the drag of a turbine is a kind of ram drag. But not all readers are knowledgeable enough. Hence a confusion can arise.
  2. Parenthetic remarks are, usually, reserved for statements that are potentially confusing. Where no room for confusion exists, parentheses are superfluous. Therefore, there's no reason to explain parenthetically the rest of the sentence. Эйхер (talk) 21:34, 3 July 2021 (UTC)[reply]
Good points, Эйхер. However, I added links to Wind turbine#Efficiency and Mechanical efficiency, which would be the preferred way for someone to explore a subject in greater depth. I suggest that the link to wind turbine efficiency obviates the need to parenthetically explain it here. I suggest that simplicity, rather than completeness, in this sentence is appropriate for the casual reader on the subject. Cheers, HopsonRoad (talk) 21:50, 3 July 2021 (UTC)[reply]
I agree, it should not be needed to add "(i. e. drag not directly associated with power harvesting)" as the link to parasitic drag should suffice to explain that to anyone unfamiliar with the term. "Clarity, brevity, conciseness". - Ahunt (talk) 00:30, 4 July 2021 (UTC)[reply]
Note, that lady Clarity goes first. Эйхер (talk) 07:24, 4 July 2021 (UTC)[reply]

Then, how about: "How fast a given wind speed can propel a vehicle in either direction is limited only by the efficiency of the turbine blades, losses in the drive train, and aerodynamic drag on the vehicle, apart from turbine efficiency."? Cheers, HopsonRoad (talk) 13:10, 4 July 2021 (UTC)[reply]

I believe that such language would make even more confusion, since even a 100% efficient turbine imparts drag, i. e."drag apart from turbine efficiency" would include the drag of a 100% efficient turbune. I propose: "and vehicle's aerodynamic drag, apart from the drag of the turbine." Эйхер (talk) 17:31, 4 July 2021 (UTC)[reply]
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