Talk:Blackbird (wind-powered vehicle)

Start discussion

This looks like an excellent start. Has it been submitted to become an official wikipedia article? Spork33 (talk) 08:01, 19 September 2010 (UTC)

Yes, it was published as an article on 21 September 2010.--Gautier lebon (talk) 11:47, 22 September 2010 (UTC)

Gautier, the image on this page is great in that it shows the cart passing a flag, with the cart's streamers going the opposite direction. But it shows the cart in it's primitive stage before we added fairings, paint, elongated the axle, etc. How about if I give you a more current photo. Technically, the cart was known as the "BUFC" in that early configuration. It became the "Blackbird" after fairings and paint. spork. — Preceding unsigned comment added by 76.212.12.199 (talk) 02:09, 2 August 2011 (UTC)

Sure, either upload the new image directly, or send it to me for uploading. But be sure to send me by E-Mail the copyright release, otherwise we cannot upload the image.--Gautier lebon (talk) 07:35, 2 August 2011 (UTC)

I am still not convinced about what we see here

Questions:

1. What happens when going exactly in the speed of the back wind?

The apparent wing is 0. What happens to the propeller rotating speed?

Does it turn by inertia to push the wheels still forward?

2. Is the propeller connected to wheels in a fixed or changing gear ratios (or through some sliding clutch)?

3. After passing the speed of wind, to a faster speed, does the propeller change direction? if before it was pushed by the wind from the back rotating the wheels forward, after passing this point it gets wind from front, which rotates it in the opposite direction, and applying a moment to turn the wheels to go backward. This part is unclear to me.

4. How accurate is "exactly wind from the behind" (180 degrees). It is well known from sailboats that if a wind component exists from the side, then the sailboat (on water, land, ice) can go faster than the wind. No exception here with the propeller.

Absolutetechie (talk) 17:06, 8 September 2011 (UTC)

2022 continuation of thread (#1)

1 When the vehicle is going the exact speed as the wind, the apparent wind is zero, just as you say. But the propeller is still moving, and is pushing the air back, and the vehicle forward. If this forward push is greater that the force of ground on the wheels pushing the vehicle backward, the vehicle will accelerate forward.

2 Not sure, but didn't see any changing gear ratio, but you are on to a great point. There IS a variable pitch on the propeller, which, when you really think about it, has about the same effect. Imagine if the pitch of the propeller was zero, at the very start, vehicle not moving. It would be just like a downwind sail. As you moved fastener, you could change the pitch, and you'd gradually change from the wind pushing the vehicle, to the wind turning the prop blades like a wind turbine, like the "up wind" case.

3 Good question, but no. But think about the variable pitch. What would happen if the pitch was very high at the beginning. Would the vehicle be pulled backwards? I would think so. It would be just like the up wind case.

4 The sailboat analogy is a good one. Think of every single blade of the prop as a sail. Going slowly, with the wind, you change the pitch so it acts like a down wind said. But as you go faster, so set it at an angle such that the ROTATIONAL component of the presser on the blade with be greater than the perpendicular BACKWARD FORCE component. Just like a sailboat tacking. Only shift your ref frame 90 degrees, you're moving the prop, like a sail boat, ~ 90 deg to the apparent wind. The adjusting of the prop pitch is just like pulling in on the main sheet as the sailboat goes faster. 130.76.112.17 (talk) 17:23, 6 May 2022 (UTC)

The idea that the propeller providing a foreword force, driven by the motion the the wheel is total crap. You can’t leach off energy from wheel, provided by the motion of a vehicle, to harvest energy to make the vehicle go faster. If you could, you could hook up a generator the system, and provide enough energy for the entire planet . That’s a perpetual motion machine. No… the propeller is harvesting engery from the wind. In the slow than wind dace, it’s like a sail, in the faster than wind case, it a turn fan driving the wheels. In the singlet case, guess what, if you don’t get a gust the thing stales, like it did. 71.81.140.89 (talk) 03:31, 9 May 2022 (UTC)

Wikipedia articles are based on Wikipedia:Reliable sources, which are paraphrased and cited in the article. Read the reference provided. If it is incorrectly paraphrased, then let us know here. If there is another source that contradicts the one given, discuss that here. I concur that the new reader will find the concept presented baffling and counter-intuitive. So, if there is a clearer way to explain what the reference describes, then you can be WP:BOLD and fix it yourself, recognizing that other editors may adjust or revert your efforts. Cheers, HopsonRoad (talk) 21:13, 14 May 2022 (UTC)

2022 continuation of thread (#1—end)

You can say whatever you want and show me a long list of articles and formulas, but at the end you have apparent wind from the front, and you reach steady state with front wind! This suggests that you may have a vehicle that after reaching a certain speed with no wind, or front wind, can sustain motion. This is a perpetum-mobile! Without wind at all you even need less wheel rotation speed. Something looks fishy to me. Has it been done in a wind-tunnel with accurate 180 degree wind?

Absolutetechie (talk) 20:43, 8 September 2011 (UTC)

There are two points you must grasp:

1. This talk page is not a forum for discussion about the subject. It's about improving the article.
2. If you can't understand the explanations in the article, in the cited sources, in the numerous videos and diagrams found online, it's unlikely that anything anyone says here will convince you. This is not the place to argue about the physics; any failure to grasp how it works isn't a problem for the rest of us.

However, I'll give it a shot. The wheels are coupled to the propeller (with a fixed gear ratio) so that the rotation of the propeller tries to push air backward faster than the vehicle moves forward. The propeller is driven by the wheels, and the wheels are driven by the force of wind on the entire vehicle as well as the propeller. At some threshold speed, the force of backward-driven air is sufficient to propel the vehicle faster than the wind speed, but the whole mechanism requires wind; it dies if the wind dies. And yes, it's directly down wind, with the wind at 180 degrees relative.

If you look at a graph of the velocity, you see it climb fairly linearly (constant acceleration) until the vehicle reaches wind speed, then at wind speed the graph seems to stall for just a moment, until the propeller starts providing more of the thrust and the speed increases exponentially until frictional forces balance it out at nearly 3X wind speed. ~Amatulić (talk) 21:14, 8 September 2011 (UTC)

Thanks much.

1. I accept your note that this is not a discussion forum and will respect it.
2. Your explanation is excellent, and I have not seen it in the related Wikipedia articles, though it may appear in some of the references. Thus I urge you to add your explanation to the articles. It will help to answer many questions and decrease or remove doubts.
3. A note: It means that until reaching the wind-speed, or actually until some time before, the pressure of the wind on the propeller actually applies a moment on the wheels against their forward direction. Thus the initial movement forward is generated by the overall wind pressure on the vehicle in spite of this fact (it is the only energy source). Disconnecting the propeller from wheels at this stage will increase acceleration and shorten the time for getting to that point. Absolutetechie (talk) 02:00, 9 September 2011 (UTC)

Good observation with your point #3. In fact, I remember reading that the designers of this vehicle said they could use your observation to create a vehicle that drove directly upwind (0 degrees relative wind) with some small modifications like changing gear ratio and blade pitch, thereby converting the propeller to a turbine that drives the wheels to move upwind.

I noticed there's a more detailed explanation also at Sailing faster than the wind#Sailing dead downwind faster than the wind. It seems silly for that section to be longer than this entire article. Much of that material should be merged to here, and a short summary left there. ~Amatulić (talk) 15:07, 9 September 2011 (UTC)

Indeed much of the part in the article on Sailing faster than the wind was originally written before Blackbird was constructed. But I'm not sure that it would make sense to remove the explanations from that article, because they are general explanations that apply to all such devices, not just to Blackbird. It may well be that other machines like Blackbird are built in the future, so maybe the general explanation should stay in the general article.--Gautier lebon (talk) 11:12, 12 September 2011 (UTC)

2022 continuation of thread (#2)

Rrr no….. it could go upwind by simply pointing it upwind. Remember that when it is going faster than the downwind, it is going upwind , for all intents and purposes. 71.81.140.89 (talk) 04:53, 7 May 2022 (UTC)

I read that it needs a different gear ratio and/or propeller pitch to be able to travel upwind. ~Anachronist (talk) 03:50, 9 May 2022 (UTC)

1, Good point

2 RUDE! 130.76.112.17 (talk) 17:25, 6 May 2022 (UTC)

No, it's a fact that this page isn't for arguing about physics, and your continuation of this discussion more than ten years after it was over is off-topic. Start a new section. ~Anachronist (talk) 03:50, 9 May 2022 (UTC)

2022 continuation of thread (#2—end)

Thanks Amatulić, but your explanations make absolutely no sense to me. Wind pushing against the cart as well as the propeller? Remember, that when the cart is going faster than the wind the wind is coming from in front of the cart.

This sounds very much like a hoax to me. Sure there are lots of dubious references for the hoax. That's what makes a good hoax. I have never seen a convincing explanation.

It is like promoting a heavier than air rock that falls up without any energy. You can have all the references you like, but it is still nonsense. Tuntable 00:59, 4 June 2013 (UTC)

Yes, the wind is coming from in front of the cart but the prop is still pushing it backwards faster, because the prop is directly geared to the wheels, which are driving the prop.

As I wrote at the beginning of this thread, if you can't understand the explanations in this article as well as the article sailing faster than the wind, in the cited sources in both articles, in the numerous videos and diagrams found online, it's unlikely that anything anyone says here will convince you.

This talk page is not the place to discuss the merit of the topic or opine about nonsense. Suggestions to improve the article are always welcome. ~Amatulić (talk) 03:31, 4 June 2013 (UTC)

As pointed out in the article, the North American Land Sailing Association has certified that this is not a hoax. So why are we still discussing that non-issue?--Gautier lebon (talk) 08:16, 4 June 2013 (UTC)

2022 continuation of thread (#3)

Down wind the fan blades act as a propeller? Hogwash! Propellers must be powered, and the power can’t come from that which is being propelled! No downwind the blades act like a sail, until the vehicle exceeds the speed of the wind. The it acts as a turbo, effectively upwind now. So, if you are thinking, you might ask how it goes from a sail to a turbo? Think. What controls are at available to the pilot. Newtonian physics, and phd scientist can get it . geez. 71.81.140.89 (talk) 05:03, 7 May 2022 (UTC)

2022 continuation of thread (#3)—end

Wikipedia isn't a debate forum. There are abundant reliable sources stating it works, and as far as I am aware there are zero reliable sources saying it doesn't. Wikipedia explicitly does not argue over truth, we report what reliable sources say. Wikicase closed. Any arguments against it constitute Original Research unless you have a reliable source saying the Blackbird doesn't work. For what it's worth, I've personally done the physics calculations on it and it does work. It's just a very counter intuitive design, and there are a lot of common erroneous assumptions that lead people to mistakenly conclude it's impossible. If anyone doubts it can work, or is looking to understand it, there are lots of discussion forums across the internet on the subject. Just use Google and ask on one of those forums. Alsee (talk) 12:22, 18 June 2013 (UTC)

The answer is kind of obvious

Unhelpful troll-explanations thread.

Look... I'm going to solve the big mystery for all of you people right now. See how all of the vehicle except the blade is painted black? Notice how the vehicle extends quite a bit out in front of the blade, but not behind it? They're getting the vehicle to absorb a ton of heat, which is then creating its own convection thermal updraft / high pressure zone in front of the propeller. Thats how it works. I cant believe there is actually some kind of debate about this. — Preceding unsigned comment added by Alonjar (talk • contribs) 13:09, 7 June 2013 (UTC) You're joking right? It also works without any paint at all, or with different colors. They painted it black likely because (a) it looks good, and (b) how else would you paint a vehicle called "Blackbird"? ~Amatulić (talk) 13:40, 7 June 2013 (UTC) That can only be a joke. The mystery is whether he was attempting to ridicule the cart-believers or the cart-deniers. Alsee (talk) 14:39, 15 June 2013 (UTC) Exactly, and not only does the body absorb heat and create the updraft, but also the wheels absorb kinetic energy from the moving ground, as demonstrated with the motorized treadmill experiment, in turn driving the propeller. It's all detailed in the article's references, really. — Preceding unsigned comment added by 190.127.232.150 (talk) 04:34, 3 June 2015 (UTC) I suggest making this section open instead of collapsed by default. It is up to the reader to decide if it's unhelpful or trolling. — Preceding unsigned comment added by 190.242.73.132 (talk) 21:55, 3 June 2015 (UTC)

First sentence

The current intro is not very good. The first sentence should briefly explain what the Blackbird is. For example:

• The Blackbird is an experimental land yacht, build to demonstrate that it is possible to sail directly downwind faster than the wind (DDWFTTW).

Then you can go off telling the whole pre-story. — Preceding unsigned comment added by Wikipedicus (talk • contribs) 19:39, 15 September 2013 (UTC)

Very good suggestion, I have implemented it.--Gautier lebon (talk) 19:32, 16 September 2013 (UTC)

External Link to Blackbird website incorrect

The external link to the Blackbirds web page takes me to what looks like a Chinese ad disambiguation page. After putting it through Google translate it seems like a financial scam. Does anyone know if their site still exists or is it gone for good. A quick google did not locate it. I will take down the link for now but if any of you want to know it was http://www.fasterthanthewind.org/ ,which seems like it should be correct so maybe they just stopped paying for the domain. Thanks Washyleopard (talk) 13:24, 8 July 2014 (UTC)

If it matters then link to the archive.org pages. https://web.archive.org/web/20110705142913/http://www.fasterthanthewind.org/ Fxmastermind (talk) 12:58, 9 November 2015 (UTC)

Template:Italic title

I plan to use Template:Italic title on this article, unless there is an objection, since WP:ITALICTITLE states that "names of ships, the titles of books, films, and other creative works, and foreign phrases are italicized both in ordinary text and in article titles". The resulting title would become Blackbird (land yacht). Please let me know, if there is an objection. User:HopsonRoad 01:17, 27 January 2017 (UTC)

Origins

The French version of this article claims a first version in 1910, but the English one doesn't mention it. If this is an error or exaggeration on the French article, it should be removed (I'm willing to do so), if not it would be worth mentioning here.

Anybody knows more about that?

Such a description belongs in the body, not the lead of the French article. The French reference checks out, but not in 1910 as the first example of a propeller-driven, upwind craft. James Brown Herreshoff created such a model in 1850. See: Capt. Nat Herreshoff, the Wizard of Bristol p. 48. Cheers, HopsonRoad (talk) 13:40, 12 June 2021 (UTC)

Dispute

People still seem to be disputing this, including at least one physics professor (https://www.vice.com/en/article/pkb3pk/a-physicist-and-a-youtuber-made-a-dollar10000-bet-over-the-laws-of-physics). Is that worth a mention? — Preceding unsigned comment added by 134.41.158.156 (talk) 18:46, 21 June 2021 (UTC)

I would say it is. Melmann 19:51, 30 June 2021 (UTC)

 Done See: Blackbird (land yacht)#Controversy. HopsonRoad (talk) 15:49, 4 July 2021 (UTC)

Theory

The “Theory” section of this article looks like it describes the propeller as a rotor that the wind pushes around. This doesn’t make sense because once the vehicle reaches windspeed, the wind cannot push the rotor anymore. For more information, see the Veritasium video about this vehicle on YouTube (https://www.youtube.com/watch?v=yCsgoLc_fzI&t=1s).
Also, calling this vehicle a “land yacht” is misleading because it is not propelled the same way as a yacht. --Rwilkin (talk) 13:10, 4 July 2021 (UTC) PS: Perhaps the bit about using the propeller as a rotor relates to Rick Cavallaro's video about the vehicle going upwind (instead of downwind), but that is not specified.

Funny that you should comment on this section, Rwilkin. I was planning on bringing the Theory section of Wind-powered vehicle#Rotor-powered across, once consensus is reached at Talk:Wind-powered vehicle#Latest tweaks.

As to the term "land yacht", I concur that it's unfortunate, because people sleep aboard yachts, but not on these vehicles. Perhaps we should make a RfC to change the heading to Blackbird (wind-powered vehicle).

The video that you cite is already in the article by reference and in External links. Cheers, HopsonRoad (talk) 15:47, 4 July 2021 (UTC)

Request for Comment: Move title to Blackbird (wind-powered vehicle)

I note that Land yacht redirects to Land sailing, where all the vehicle shown are sail-powered, and that Wind-powered vehicle includes rotor-driven vehicles, like Blackbird. Furthermore, Merriam-Webster defines "land yacht" as a "3-wheel wind-driven recreation vehicle consisting usually of a bare-frame structure and a single sail and used especially on areas of firmly packed sand" or "a large motor vehicle", which shows ambiguity of meaning. Furthermore a Yacht often connotes on-board accommodations. Therefore, by the principle of least astonishment, I recommend moving this article to Blackbird (wind-powered vehicle). Cheers, HopsonRoad (talk) 16:00, 4 July 2021 (UTC)

• Support per [1][2][3], I haven't seen sources personally that refer to this vehicle as a "land yacht". Loganmac (talk) 17:39, 4 July 2021 (UTC)
• Support per sourcing. I didn't see much in the way of land yachts, but did see wind powered vehicle and wind powered car. ScottishFinnishRadish (talk) 19:51, 4 July 2021 (UTC)
• This is not an RfC matter, please use the process described at WP:RM. --Redrose64 🌹 (talk) 22:33, 4 July 2021 (UTC)

 Done Per WP:RM AND HELP:MOVE. HopsonRoad (talk) 01:51, 5 July 2021 (UTC)

Ivanpah runs

Hey folks. Rick Cavallaro here. I'm not familiar with the process here, so most likely I'm doing it wrong. I just wanted to offer a minor clarification...

"This was not a NALSA-sanctioned event but was presented as a demonstration to the NALSA Board of Directors that the vehicle was capable of progressing dead downwind faster than the wind"

When we first met Bob Dill at Ivanpah, it was at a regular NALSA sanctioned event. I believe they call it the Americas Cup dirt boat race if I recall correctly. If anyone cares, I can check with Bob Dill and get confirmation. It's true however, that we were simply invited guests, and not part of the sanctioned event.

Please forgive me if I'm doing this all wrong, or in the wrong place. I'm willing to learn.

Spork33 (talk) 07:55, 28 August 2021 (UTC) Rick Cavallaro

Thanks for reporting in Spork33/Cavallaro. Indeed, this is the right place to discuss the article. Wikipedia is supposed to be based on Wikipedia:Reliable sources. Since the passage that you cited was unreferenced and apparently incorrect, I have removed it. Cheers, HopsonRoad (talk) 21:21, 30 August 2021 (UTC)

Apparently first report of such a vehicle was in 1904

From Popular Mechanics 1904 Volume 6 Issue 10 Page 1009: https://archive.org/details/sim_popular-mechanics_popular-mechanics_1904-10_6_10/page/1008/mode/2up 2600:1700:6AE5:2510:0:0:0:46 (talk) 02:15, 1 January 2023 (UTC)

I have transferred mention of this invention to Wind-powered vehicle. HopsonRoad (talk) 15:07, 1 January 2023 (UTC)

The purpose of that 1904 vehicle was to drive upwind. The Blackbird can do that also with a different gear ratio, but unlike that 1904 vehicle, the purpose of the Blackbird was to drive downwind faster than the wind, using wind power. Not the same thing. ~Anachronist (talk) 15:12, 1 January 2023 (UTC)

it's trivial to go upwind in something like this. Downwind faster than the wind is legitimately impossible and this site in general loses legitimacy when it lists things that are legitimately impossible. Their "treadmill" experiment was powering the propeller by the treadmill. Their "spiral" display doesn't change the fact that in the direction the wind was blowing, they still weren't going faster than the wind. It's literally impossible. EmperorOrwell (talk) 14:09, 19 March 2024 (UTC)

Read and understand the references that the article is based on. Going downwind faster than the wind seems counterintuitive until one realizes that it's a propellor driving wheels and not a sail attached to a mast that is propelling the vehicle. This is a settled discussion. Sincerely, HopsonRoad (talk) 16:30, 19 March 2024 (UTC)

"DDWFTTW cart" listed at Redirects for discussion

The redirect DDWFTTW cart has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at Wikipedia:Redirects for discussion/Log/2024 January 22 § DDWFTTW cart until a consensus is reached. Utopes _{(talk / cont)} 07:38, 22 January 2024 (UTC)

DDWFTTW stands for "directly downwind faster than the wind". I have a vague recollection that this was the title of an article that became more appropriately named. It doesn't seem to be a very current term. HopsonRoad (talk) 01:56, 23 January 2024 (UTC)

@Utopes: Googling for DDWFTTW reveals many explanations of the meaning with no ambiguity. I have added a parenthetical note to the lead explaining the acronym. ~Anachronist (talk) 02:53, 23 January 2024 (UTC)

All good; the words for "directly downwind faster than the wind" were in the article (even if not abbreviated as DDWFTTW), hence I ended up withdrawing the RfD as the page does have that background, just not all the way for making this title seem plausible and not just an unmentioned/unreferenced supposed synonym. Utopes _{(talk / cont)} 03:07, 23 January 2024 (UTC)