Wind powered electric car?

Posted: July 24, 2015 by tchannon in Uncategorized

Engage brain and funny bone.

Some time ago an anonymous, a newbie, asked a question in a physics discussion forum, fully admitting they didn’t know the answer. Went along the lines of wind turbines on a car ought to be able to fully power it from wind and would carry on for hundereds of miles.

Image

Image credit given later.

To the forum’s great credit this question was treated sensibly, if obviously with tongue biting about laws of thermodynamics, perpetual motions machines, yada yada. Boats came up too, they use sails.

I recall the boat with an airscrew instead of sails, worked fine if not really practical for everyday use.

Quite naturally the next tack (sic) was, well it can’t sail into the wind. Of course it can. Right into the wind. Just a matter of forces and efficiencies.

This is all about losses, efficiency, getting the sums right.

Then came the expected revelation, yeah, boring, folks do that with cars and provided evidence.

Followed by others dropping in with offensive words about the impossibility. Really rather amusing but saddening over the state of engineering knowledge.

The Dutch race land-yachts straight into the wind

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Poster for the 2014 event, image from this promotional item.

Video from the 2008 event

https://www.youtube.com/embed/UuffDMkHhEo?rel=0&autoplay=0

This year’s event is soon http://www.windenergyevents.com/

Not quite as crazy as ice Yacht racing, at sea some places, lakes elsewhere, seriously fast. Ice is rarely smooth. Seemingly recently measured 84mph but much higher has been claimed.

Ever since electricity came to the front, late 1800s, man has obsessed, trying to put it forwards as the answer, means is the end. In reality other methods are often better.

Post by Tim

Comments
  1. Alan Poirier says:

    Trying to imagine them in eight lane gridlock. Can’t stop laughing.

  2. Sorry. Can’t comment. Too hard to type with tongue lodged in cheek.

  3. From (ironically) “The Flying Dutchman”:
    “To rely on wind is to rely on Satan’s mercy.”

    Winners of the competition must therefore be Satanists.😉

  4. tjfolkerts says:

    It is also possible to move downwind FASTER then the wind.
    https://en.wikipedia.org/wiki/Blackbird_%28land_yacht%29

  5. Graeme No.3 says:

    Can they deliver a wardrobe? It is just up the hill.

  6. oldbrew says:

    Sand yachting was ‘suspended’ = banned at St. Annes (near Blackpool) in 2002 after a day-tripper was killed. Worked there for a few years in the 90s.

    http://en.wikipedia.org/wiki/Lytham_St_Annes#St_Annes

    ‘the distance between high and low tides can be at least a mile’
    http://www.lytham-stannes.com/stannes/stannes_today.htm

  7. Part of me says “great -this shows science works and sometimes contradicts what everyday experience tells us”.

    But part of me groans because now all those numb-skull potential motion machine “gullibles” (aka renewables) pushers will point to this and say “look more energy can come out of a windmill than goes in”.

  8. tchannon says:

    SS, your point about half ideas is good.

    I think we need to address the many half brain ideas, a spot of fun for tech types, but not practical for sound reasons, take it away from the could might future possibly brigade. The selling press release or one of so many science papers.

  9. tchannon says:

    tjfolkerts,🙂

    Actually this article was mostly prepared a little while ago, decided to pop it up now, for which there is an anterior motive, a discussion which needs to be had. Letting on the motive will appear in due course, won’t be guessable.

    Like so much there is the counter-intuitive or the needs thinking, your point being one of these.

    What exactly is the wind speed?

    If the energy extract device in in a free gas flow field with zero relative movement there is no gradient to exploit, a bit of a blow to the idea.

    This is not the case, there is a surface and this is within the boundary layer, turbulent too. True surface speed is zero, true wind speed is hundreds of metres up. The law involved, there isn’t one, only heuristics, approximations. Even more fun comes from the various aerodynamic parameters to do with gas pressure, speed, mass, etc. and of course surface roughness and history.

    Same considerations apply to the land yachts above, they are not running into one wind speed but a vertical gradient, then there is ground effect complicating things further. Aerodynamic drag is altered by the proximity of the ground, raises it but also raises any aerodynamic lift, hence the Russian ground effect heavy lift high speed vehicles — http://www.wired.com/2011/06/ekranoplan/

    The upshot is that for a land yacht the situation is complex. Airscrew is seeing higher wind speed, the body is in slower air but also in high drag.

    Downwind there is no wind speed as such, is a vertical gradient. What exactly can be extracted from the potential, difficult to say, practical is another matter.

  10. Curious George says:

    To rely on wind .. or to rely on the Sun. So far, the wind is winning; the Solar Impulse 2 plane will take much longer to cross the Pacific than a sailboat takes (I hope it will actually happen). On the positive side, they plan to fly to Phoenix, strictly off-limits to sailboats.

  11. oldbrew says:

    George: VERY MUCH longer – some batteries damaged beyond repair on Solar Impulse 2.

    ‘Battery problem grounds Solar Impulse until 2016’
    http://arstechnica.co.uk/science/2015/07/battery-problem-grounds-solar-impulse-until-2016/

    ‘the cooling system wasn’t able to handle rapid ascents or descents in tropical conditions. The unfortunate result was permanent damage to some of the batteries, which will require several months to repair.’

  12. ferd berple says:

    http://www.wired.com/2010/06/downwind-faster-than-the-wind/
    Wind-Powered Car Travels Downwind Faster Than the Wind

  13. ferd berple says:


    https://en.wikipedia.org/wiki/Greenbird
    The Greenbird reached a peak speed of 126.1 mph

  14. ivan says:

    Most of the film clip appears to show that these ‘cars’ are direct mechanical drive with no battery or electric motors involved. If they had batteries and electric motors then they would not need pushing to get started.

    I do have to wonder if this is just a simplification of the old land yacht – away of removing the need to trim sails and supposedly look ‘cool and green’. Although, I have to admit, travelling in a land yacht (in the 70s) was rather fun.

  15. Fanakapan says:

    The two words Turbine and car made me think of Rover’s attempts to utilise a gas turbine instead of a reciprocating engine. I had thought that the problems of variable motor speeds, and fuel consumption doomed the idea to failure.

    However a little web surfing revealed that Chrysler had much more success with the concept, to the point where the turbine may well have been an acceptable power unit. Nice little website here; http://www.turbinecar.com/turbine.html that gives a surprisingly complete picture of their efforts.

    Given the fuel flexibility and greater ease of manufacture that gas turbines offer, its surprising that the topic does not seem to have resurfaced. All the more so when one considers the advances that have been made in ceramics and turbines since the early 70’s.

    As for cars with wind turbines, that’ll just be in the Heath Robinson category🙂

  16. oldbrew says:

    There was the Jaguar C-X75 – but they pulled the plug on it.

    ‘The batteries driving these [electric] motors are recharged using two diesel-fed micro gas turbines instead of a conventional four-stroke engine. It is described as an ideas model that will influence future design and technology.’
    http://en.wikipedia.org/wiki/Jaguar_C-X75

  17. John Silver says:

    Swedish pirates in desert:

  18. John Silver says:

    Vive la France:

  19. tchannon says:

    Good sails pitch there John.

  20. John Silver says:

    The pirates are sailing to Treasure Oasis.

  21. steverichards1984 says:

    It makes you wonder why aircraft and cars etc have engines! Using this technology, you just give them a push start and away they go…………

  22. Fanakapan says:

    oldbrew, good link there for the Jaguar🙂

    I’m wondering though if current thinking vis a vis electric motors and cars is not putting the cart before the horse ?

    If its possible to have compact turbines, then it would make more sense to have the turbine running at a constant speed to drive a supply for a motor, with a modest battery as a sink in which to dump surplus power ? As opposed to dragging around a couple of hundred kilo’s of battery that offers a restricted range, and probably costs more to replace than the value of the vehicle after 5 or so years usage.

    In the absence of a huge technological breakthrough, batteries are always going to be expensive and heavy. So the idea of running a vehicle for any distance by means of stored electricity is bizarre ?

    However, I’d think that both turbines and batteries are pie in the sky. Given the existing manufacturing and service infrastructure is wedded to the reciprocating engine, it’d probably take 60 years to transition to turbine power ? As for batteries, they’re going to take something out of the Roddenberry book in order to be considered practical for the sort of travel we now enjoy.

  23. tchannon says:

    Gas turbines have serious part load efficiency problems.

    Evidence?

    Sales site but nevertheless, manufacture arrays of bang bang engines, turn on or off as required for variable load.

    Have a dig around the site.

    http://www.wartsila.com/energy/learning-center/technical-comparisons/combustion-engine-vs-gas-turbine-part-load-efficiency-and-flexibility

  24. Konrad says:

    Wind powered land vehicles are entirely possible, but not practicable. I know this from a friend and I mounting his wind surfer sail to my skateboard many years ago. The results in a large carpark were incredible speed, death-wobbles and serious gravel rash. (if you live, you learn).

    If you want a wind powered to work at wind occluded street level in a built up environment, my advice would be to put the wind charger on the roof of your house and use it to charge a swappable battery pack for an electric car.