JoNova

A science presenter, writer, speaker & former TV host; author of The Skeptic's Handbook (over 200,000 copies distributed & available in 15 languages).


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How to save billions of gallons of gasoline

Scientists at Lawrence Livermore National Laboratory have looked at drag-reducing devices on semi-trucks, and say they can conserve billions of gallons of fuel plus tens of billions of dollars. This not exactly rocket science.

Boat-tailed bullet (left)

The researchers estimate that trailer-skirts and boat-tails (see the pic below) could reduce drag on trucks by as much as 25%, which means they would save about 13% on their fuel bill. Apparently only a few percent of US trucks use these devices at the moment, and the researchers claim they can make up to a 19% improvement in fuel economy.

If these work that well (and are not too expensive or painful on carrying capacity), the free market will take care of this pretty quickly.

Boat tails means a tapered shape at the back of the vehicle. They are already used on bullets (and boats, obviously). There are pics of “boat-tails” on trucks below, but my favourite shot is this boat-tail on a car. A DIY masterpiece. It’s a “Pontiac Firefly (Canadian Geo Metro). The maker Darin Cosgrove says  “the Firefly squeezed out 64 miles per gallon during testing.” I can’t see mums rushing to go food shopping in it though. Boat tails on trucks are a lot less ambitious.

A homemade boat tail on a car from cardboard and duct tape.

Researchers estimate it could save $26b in fuel

Newswise — WASHINGTON, D.C., November 25, 2014 — Each year, the more than 2 million tractor-trailer trucks that cruise America’s highways consume about 36 billion gallons of diesel fuel, representing more than 10 percent of the nation’s entire petroleum use. That fuel consumption could be reduced by billions of gallons a year through the use of drag-reducing devices on trucks, according to studies by researchers at Lawrence Livermore National Laboratory.

Fluid dynamicists Kambiz Salari and Jason Ortega ran aerodynamic tests on a detailed 1/8 scale model of a semi-truck in the wind tunnel facilities at NASA’s Ames Research Center at Moffett Federal Airfield in California.

“Even a minor improvement in a truck’s fuel economy has a significant impact on its yearly fuel consumption,” Salari said. “For example, 19 percent improvement in fuel economy, which we can achieve, translates to 6.5 billion gallons of diesel fuel saved per year and 66 million fewer tons of carbon dioxide emission into the atmosphere. For diesel fuel costing $3.96 per gallon, the savings is about $26 billion.”

[Newswire]

This is what a boat-tail looks like on a truck. (Not much like any boat I’ve seen).

These might be what the trucks skirts look like. This pic was found on this ecomodder site. Though there are other side skirts for sale that are smaller.

Anyhow. Interesting idea. I like efficiency, even if I think we need more CO2, not less. Given the hassle with parking and garage space, maybe the answer is an inflatable one that pops out at speed and packs away for parking? (The truck “tail fins” do pack up BTW).

Will the Greens rush to support this fairly easy free market possibility, or will they ignore it because it does not create a dependent lobby group who would campaign for big (green) governments for ever more? Here’s a solution that allows people to travel further or save money, encourages independent business, and needs no government intervention.

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176 comments to How to save billions of gallons of gasoline

  • #
    Bob Campbell

    Uhm, where are the rear lights? How would it go getting from the road, across the gutter, and into my drive?

    50

    • #
      Olaf Koenders

      Give it a minute and the RTA or VicRoads will trash it because it represents some kind of hazard – which they didn’t sanction in their committee meetings.

      70

    • #
      cedarhill

      Same location on the trailer as they’ve always been. These have been in use with some truck lines in the US for several years. The fact that not all carriers are installing and using these configurations almost always mean it’s not economical to convert their fleets. There’s the capital cost plus a frequently overlooked “time” factor (e.g., folding and resetting for unloading).

      Truckers are “load” oriented. The more loads, the more pay a driver earns. Even if hauling from Seattle to Jacksonville, a team can do it in two-three days. Slow them down at both ends and then imagine sitting in a cab thinking about how many loads they lose per year (you have lots and lots of time to think in a cab plus chat with other drivers). Fuel savings aren’t usually passed along to drivers (unless owner-operator).

      Fleet averages went from around 5 mpg to nearly 7 mpg after the oil embargo of the Carter years. Fleets were highly motivated to increase mpg. They continue this up to today with most fleets recording about 8-9 mpg. These figures are highly accurate since carriers pay fuel taxes based on mileages driven in a state using their actual fuel purchases — and they’re audited by just about every state since the taxes collected are enormous.

      Then, supposes fleet averages do go to 10-11 mpg regardless of method. After patting themselves on the back and planning their next IPCC world meeting, they’ll raise taxes to make up the shortfall of the fuel taxes. Do the tax math — fuel tax rates for dieel in the US are about half a dollar per gallon (US); the average carrier averages about 120,000 miles per year (double for a team); and about 3 million on the road. Then replace the gov revenue lost…


      A really useful comment. Thanks Cedarhill. Did seem odd that only 2 -3% were using this. It’s not rocket science. – Jo

      140

      • #
        NielsZoo

        There are also considerations as to overall length of the rig. There are length limits which roadways are designed around for normal vehicles and those are also defined legally. My guess is that the max tail length you could add to the trailer would have to be offset by the length of the tractor/trailer gap, which is usually minimized for highway driving and increased to allow large turning radii in urban areas. That means the “tail” would need to be easy to load through and adjustable enough to stay inside safe and legal operating parameters. (Oversize load fees would be real killers for normal trucking.) I see most of those add on tails are only a few feet long and may not be that helpful. Increasing that length would be decreasing load area and that’s probably a really bad thing as well. You gotta think that the major cost to truck operation would be fairly well balanced cost wise after all these years of really expensive diesel fuel.

        Besides, here in the US all we had to do was follow Obama’s edict advice and put air in our tires, get tune-ups (on fuel injected, computer controlled engines?) and we completely got rid of foreign oil imports.</sarc>

        90

        • #
          jorgekafkazar

          I can think of one foreign import I wish we could get rid of.

          30

        • #

          It must definitely be the length restrictions. In Sweden a lorry is limited to 24 meters and 60 tonnes and probably in Finland as well. This way, one can get three loads of timber on them. In the rest of Europe the limit is 18 meters and only 40 tonnes. This was an exception that Sweden was “allowed” when we unfortunately joined the EU.

          To gain length, the engine is underneath the cabin in Europe, not in front of it as often is the case in the US and as on lorries of old.

          So the only way this could work is if lorries were allowed a few extra meters on motorways and other long distance travel, and if these devices can be easily be taken off an put back on. Otherwise they will lose 30-40 m3 worth of load.

          10

      • #
        Doug Proctor

        The problem of lost taxes is always the problem with increased efficiency or reductions in usage. As long as governments spend more than they take in, or struggle to balance the budget, there will be a conflict here.

        The carbon tax is, in some ways, a way to deal with this, except that the extra money comes up front. As long as the tax doesn’t go into general revenue AND get spent to the max, it will work and not require replacement later. But of course that will not happen.

        In Canada we had a Manufacturers Sales Tax. What it did was hit the strict Canadian manufacturing sector. It hurt cross Canada-USA competitiveness as American products came in at a lower cost-base. . The Conservative Canadian government got rid of the MST but said the a General Sales Tax, or GST, would be imposed. The opposition party, Trudeau’s Liberals, won a snap election on the promise not to bring in a GST …. and then brought it in.

        But the GST HAD to be brought in. Otherwise government tax revenue would fall significantly. Which was not acceptable in a deficit-spending government. People in business knew this, but the voting public didn’t

        Our government spending is not tied to its revenue stream because it controls its revenue stream. That is the fundamental problem with government spending. Efficiency and smaller government will never happen when fiscal imbalances can be countered by increased taxation.

        Look at the city of Detroit as an extreme example of the inability of a government to respond to a collapse of revenue: despite years of advance notice, the contraction of services could not be done under the perceived mandate of public service and the system of electoral governance that determines electoral success by telling the people what they want to hear, not what they need to hear. A complete failure was inevitable.

        Eventually reality bites your ass. I suspect this is how the Roman Empire ended. Reality storming the gates, not reasonable accommodation with a changed reality happening in the halls of power. Right now America survives because however badly it is run, it is still the best run (business-wise) in the world. Lord help America if China gets its act together. Printing greenbacks won’t help a system that can’t keep true expenditures below true revenue.

        70

  • #

    Productivity gains and economic growth can occur as a consequence of SPENDING on energy saving technology. How many businesses and governments get it?

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  • #
    Niff

    Jo. You got it in one. There are no capitalist-crushing advantages in being more efficient…so no green interest whatsoever.

    71

    • #

      nice rhetoric. See if you can count the references to efficiency in this page – http://greens.org.au/cleaner-cars

      If you have proficiency with google you can find many more including detailed policy documents that site economists and engineers who work on the impact of efficiency on the market. This organisation for instance and fine work they do too http://energy.anu.edu.au/research/energy-efficiency-demand-management

      018

      • #

        Gosh GeeAye, they’ve set up a whole web page.
        So google “Christine Milne aerodynamics” for us.

        180

        • #

          Aerodynamics aren’t that important for a hot air balloon other than in determining the direction it’ll drift. ;-)

          Speaking of drifting in random directions; Germany’s Greens are seen to be struggling to find relevance.

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        • #
          Aaron M

          I’ve solved it Jo. (pfft)

          Ahem.

          In the old Formula 1 days, there was widespread use of ‘ground effects’ that gave the cars superior grip by guiding and deflecting airflow where it was most needed. It was a permanent feature of iconic cars from back in the late 70′s and the black Lotus 79 John Player Special was I think the first to utilise this ‘free’ grip.

          Unfortunately, it made overtaking very hard, as the ground effect caused huge disruption to the boundary layer of the car behind and to the side. This effect is still around in NASCAR today in fact, but in a bad way, and if you sit behind a competitor you encounter a vacuum. This can be used to your advantage and if you move to the side you can upset his boundary layer making it harder for him to steer.

          So what does this mean for the truck? Well….

          Future F1 technology MAY include a servo actuated ground effects system, that allows grip to be increased by the servo moving a panel to direct airflow where it is needed when the steering wheel is turned, and then retracting when straight or if another car is sensed to be close enough to overtake….rules to be decided of course.

          What I imagine would be a possibility, is if the shipping containers around the world could be retrofitted with an air activated set of ‘wings’ to produce the conical boat tail shape at the rear of the container. When not in use, these wings retract flush into the side of the container. This works great because no trucks need to come off the road, and containers still fits like neat little leggo bricks when setting sail.

          Hell if it was only applied to all the worlds shipping containers and pantek trailers, it wouldn’t really be a big down time on the trucking industry.

          Since an air compressor is one of the most essential parts to activating a trucks braking system, this air pressure could be plumbed in to a spare port on any trucks compressor using a simple widely available ‘nitto’ coupling, and voila, at a certain speed, the boat tail activates, fuel consumption drops and money falls from the sky, Christine Milne hugs Tony Abbott and Scott Morrison and Penny Wong share a Kebab.

          Ive already got the linkage system, the retrofit and the materials selected in my head. Any investors? :D

          80

          • #
            Aaron M

            This can be used to your advantage and if you move to the side you can upset his boundary layer making it harder for him to steer.

            I know, I know, NASCAR drivers are busy enough just remembering to turn left, but seriously on the other side of 300kph, a little airflow issue can really affect your ability to ‘turn left’, and certain maneuvers can cause loss of control.

            Its a lot for a NASCAR driver, you know ;)

            30

          • #
            richsrd

            kickstarter.com

            10

        • #
          Gee Aye

          I googled it but I don’t understand your cormment

          25

        • #
          Gee Aye

          actually wrote longer response than that but net froze. Maybe NBN was protesting or something. Anyway i tried various derivations of milne etc and got no where. I found nothing that justified Niffs comment and since my link already demonstrated that Green policy inludes efficiency it is hard to imagine what was being clamed.

          I also took the time to see what google gave usiong senior minister’s and shadow miniter’s names with aerodynamics plus jo nova aerodynamics. the polititians gave little. Jo Nova had lots of links with some positive comments and some direct advocacy.

          06

          • #
            The Backslider

            Green policy inludes efficiency

            Please tell us all what is efficient about a wind farm as opposed to a nice coal fired power plant.

            40

          • #
            The Backslider

            While you are at it, please tell us what is “green” about a wind farm.

            40

          • #

            BS… I vote on the other side of politics so don’t ask me to defend the Greens (and have you ever seen me do so). My comments above were pointing out Niss’s lazy, disingenuous and factually incorrect comment.

            03

            • #
              The Backslider

              don’t ask me to defend the Greens

              But you are defending the Greens.

              20

              • #

                Well I say it is not so there. I was pointing the first poster to facts. If someone makes a false assertion and it is pointed out it doesn’t mean I support who or whatever was the subject of the assertion. In the context of debate on climate change empty rhetoric like that made above makes the side producing the rhetoric look foolish. There I go defending good scepticism.

                11

  • #

    All pretty much useless really.

    I feel sure that if the fossil fuel greenhouse gas emissions targets were explained in the real terms, that people might pretty soon get up in arms.

    A 25% reduction means effectively that one in four of every car, truck, bus, train etc has to be taken off the road.

    Who gets to pick which one in four loses their car, eh?

    All you (insert stocking thread count measurement term here) will be first would be my guess.

    Tony.

    111

    • #

      Sorry Tony, what is useless? I’m not following how your argument relates to the story.

      If I owned was a company owner and was told that a 1000s of dollars investment to retrofit a truck would be paid off in fuel savings (via a reduction of 20%) in 2 years then would positively impact profits, that is an investment I’d make. Why would I need to take trucks off the road?

      36

      • #
        James Bradley

        Sorry, leaf,

        In the real world a trucking company would probably turn its fleet over before they would realize any benefit for the added cost of this efficiency.

        40

        • #
          Gee Aye

          Sorry James But what is the average age of a truck?

          05

          • #
            James Bradley

            Leaf,

            Your talking interstate to gain any finacial benefit from aerodynamics and they don’t hang on to em long enough to start costing major maintenance.

            40

          • #
            Gee Aye

            data suggests more than 10 years. do you have different data?

            15

            • #
              Dave

              GeeAye

              The link you gave suggests otherwise
              57% of Trucks on the road today are Heavy Rigid
              All of these have average age of 15.6 years

              The average age of ALL trucks is 13.84 years
              All classes are increasing in age
              The Heavy rigid transport most freight over short distances

              Maybe you can pick up on a clue here GA

              Please read your own links

              40

          • #
            Dave

            GeeAye

            There are 2 major trucking companies in Australia
            Both are committed to saving fuel
            BUT
            AND this is the main point

            TIME for delivery is the major point
            Coles & Woolies don’t give a stuff about efficiency, only time of delivery

            Trucks 30 minutes late are not accepted
            The profit of these two players is more important than the fuel efficiency, and hence many drivers are on drugs, not having the regulated rests and working huge hours to pay their Prime Movers off

            The money savings is in the schedule, not efficiency of fuel

            The rest of the owners/drivers (I cart rock) is in load. Rarely do I get anywhere near 100kph, and fuel is secondary to timing. POWER, Acceleration, On time delivery & Load is number 1.

            Skirts, boat tails, under body flaring is irrelevant to me.

            Age of trucks is also not important, it is normally Kilometers.
            Some of the tippers will run 1,000,000 kilometers plus. The fuel saving is about 10th on the list.

            For some of the B Doubles that operate at night, the saving may come into play. But they are all on very TIGHT schedules, that include penalties if late.

            170

            • #
              Gee Aye

              fascinatong but nothing to do with this post, plus you added a whole bunch of unrelated info that even if true now is not intrinsic to the economy. If the trucks were 20% more efficient then someone in your scenario would be makiong more profit and less resources would be expended.

              016

              • #
                Dave

                Ok
                Gee Aye

                Nothing to do with this post?

                1. Fuel efficiency V On time Delivery penalties? You’re not in business are you?

                2. 20% more efficient? Contracts either per load over Time or Hourly.

                I don’t think you know trucks at all
                But thanks anyway

                170

              • #
                James Bradley

                Leaf,

                It has everything to do with the post, which premise you used to hypothosize what would happen if you owned a trucking company therebye projecting the premise to an action in the ‘real world’.

                “If I owned (sic -I suppose) was a company owner and was told that a 1000s of dollars investment to retrofit a truck would be paid off in fuel savings (via a reduction of 20%) in 2 years then would positively impact profits, that is an investment I’d make. Why would I need to take trucks off the road?”

                And as I posted, in the real world you’d never get to realize the financial benefits of aerodynamic efficiencies.

                There are a whole host of common sense reasons other than efficiencies and fuel savings that make the subject of Jo’s article redundant, and other financial concerns are prioritised

                They still repossess trucks.

                They still pull trucks over and fine drivers.

                51

      • #
        Aaron M

        Look at the pictures of the two projectiles instead. Both have the same OAL, one is simply boat tailed in the rear 10-15% by less angle then the ogive of the same projectile. The ballistic co efficient increases on the boat tail by about 12 to 15%.

        30

        • #
          Rereke Whakaaro

          I always understood that tailed projectiles were slightly more accurate, but had no extra range (for the same charge weight).

          And with truck efficiency, we are talking range, are we not?

          40

          • #
            Rod Stuart

            Gerald Bull developed artillery with a “boat tail” enclosing a small solid fuel rocket motor.
            The purpose of the rocket motor was not to increase velocity, but to increase accuracy.
            South Africa used this artillery against Angola and could achieve accuracy of plus or minus a few meters at four kilometers.

            30

        • #
          NielsZoo

          The boat tail of a bullet is designed to keep the BC (ballistic coefficient) up while the projectile is transonic. RW, that does give you more range as the longer you can stay transonic, the less drag you have and distance and accuracy improve. I just can’t see that happening with most big rigs unless the Mythbusters are trying something new.

          30

        • #
          James Bradley

          Aaron,

          Financial efficiency can also be improved by using a lighter load and jamming that sucker further into the case.

          10

      • #
        Ted O'Brien.

        Did you get that advice in an email from Nigeria?

        00

    • #

      The 25% reduction in aerodynamic drag doesn’t realistically translate to 19% reduction in fuel consumption for most trucks. It just might be work for long-haul trucks travelling long distances at high speeds on highways. See Fig 5.1 (p34) in this document. Aerodynamic drag only reaches the magnitude of other drag components around 100 km/h; when a 25% reduction in aero. drag would mean a 12.5% reduction in total resistance/fuel consumption.

      80

      • #
        Binny

        Drag is only one part of the equation,the main part is gravity. Any long haul truck driver can tell you exactly where every watershed is(no matter how slight)You don’t notice them in a normal car, but you certainly do in a truck. Also the trade off between regulated length, and long capacity would be a large factor.
        I suspect this is a ‘laboratory’ result that won’t translate well into the real world.

        20

    • #
      Aaron M

      Oh, deniers… I had to Google that one Tony, touche!

      10

  • #
    Graeme No.3

    cargo box.Years ago someone did some studies and found that a van like car could have low drag. Their best choice was a flat front sloping back to a flat roof, and a vertical V shaped tail. Thus the van had 5 sides as seen from the top. Doesn’t appear to have gone anywhere.

    There was a company NoseCone who were making fibreglass fairings for trucks. Mostly for the cabin roof so the airflow was diverted around the front of the big square

    20

    • #

      As far as cargo boxes go, you can’t go past the shape of the classic VW Type 2 Transporter (aka “Kombi”) from ca. 1949.

      Surprisingly for many, it’s quite aerodynamic with a Cd of about 0.44; comparable to that of the many Toorak Tractors preferred by Green voters.

      40

      • #
        Richard of NZ

        The most surprising thing about the Kombi is that its coefficient of drag is as good as, or better, than a series one E-type. The Jag does of course look better.

        10

    • #
      Olaf Koenders

      NoseCone still make their products, but no prices that I could see on their website. I would estimate all that fibreglass to be rather expensive.

      They’re only covering flat frontal area though. I’d expect any sideskirts or boat-tails to be easily removable or fold out of the way for loading docks etc.

      Still, boat-tails would effectively lengthen the truck by a certain amount and this can’t be used to carry cargo – it’s simply empty. This lengthening might also conflict with road regulations.

      Many trucks (and those silly Denny utes) have large mudflaps across their frames front and rear too, increasing drag a large amount. On the trucks it may save paying for someone’s windscreen if it stops the rocks being flung, but on the utes it just looks idiotic IMHO.

      20

  • #
    ossqss

    Thanks, interesting stuff!

    I have always felt it better to sweat than shiver, no matter the aerodynamics involved, but saving money is always attractive.

    Living in Florida (flat land), a couple extra gears would probably do well on the highways.

    30

  • #
    Greg Cavanagh

    I love it.
    I could buy my 455cu Buick Boattail, AND gain a 19% fuel saving.

    https://www.motorbase.com/picture/profile/2014/09/21/buick-riviera-boattail-1972/

    30

    • #
      Carbon500

      I like the Buick Boattail Greg – now that’s a proper American car, one that’s got character. We’ll never see their like again, sadly!

      00

  • #
    Bruce J

    To achieve these aerodynamic efficiencies, the vehicle has to be moving and at a reasonable speed, so little or no effect in cities where traffic is travelling at low speeds. Under these conditions much greater improvements can be achieved by changes to driving style. At higher speeds, minor changes to the vehicle shape and frontal area have greater effect than these hang on tails which extend the length of the vehicle, or, as maximum vehicle length is mandated, reduce the length available for cargo. As usual, there are trade-offs, and fuel efficiency is affected by a lot more, easily managed factors than vehicle aerodynamics.

    Any improvements must also be marketable and have some appeal to the consumer. A few years ago Audi improved the drag coefficient on their Audi 100 down to 0.26 (when the average was about 0.40) by making a lot of relatively minor detail changes which did little to alter the appearance of the car. However, the research investment was not recovered from extra sales as nobody really cared. Sales stayed about the same.

    50

    • #

      Pretending that the car in the above picture is approximately the dimensions – ie about a 30% increase in length, then the engineering would absolutely have to allow retraction not only for parking but for slower speeds or in heavy traffic. Imagine the thousands of cars bumper to bumper on a 20km stretch of the Eastern Fwy in Melbourne – how many cars would be queuing on feeder roads to get on to the freeway as a result of the increase in length of 1m/car?

      51

    • #

      A few years ago Audi improved the drag coefficient on their Audi 100 down to 0.26

      That was (unfortunately) more than a few years ago. Audi adopted the basic shape of the NSU Ro 80 that had a Cd of 0.30 in 1966; and updated it a little (around 1981) with e.g. recessed wiper spindles and better flush windows to make the Audi 100 “C3″ which officially still had a Cd of 0.30 despite the more conservative styling.

      60

  • #
    Hasbeen

    I have a couple of examples of reduced drag reducing fuel consumption.

    I was running a couple of international cats in the Great Barrier Reef tourist industry. The 29 meter, 350 passenger boat ran with a nose high attitude. I knew a little about the trim tab usage to correct attitude in racing & high performance ski boats, not much, but a little.

    Not game to do anything serious, I had 4 wooden wedges made at a 6 degree angle, which we bolted & bonded to the existing planning boards at the stern of the boat.

    With them the boat trimmed much better. More importantly, it could now maintain 26 knots, fully loaded at 150 RPM lower revs of the twin 1250 horse power V16 engines.

    Fuel consumption dropped from 285 gallons of diesel per hour per engine, to 48 gallons per hour per engine.

    Annual savings just over $1,000,000. with this boat & the 26 meter boat similarly modified.

    On a domestic scale, I recently fitted low drag, easy running tyres to our shopping trolley. We have owned the thing for years, & all 3 kids used it for a while as their first car, as well our usage.

    With these new “slippery” tyres it is now using just under 8L/100 KM, where with quality performance tyres it has always used a little over 10L/100 KM.

    80

    • #
      Truthseeker

      With these new “slippery” tyres it is now using just under 8L/100 KM, where with quality performance tyres it has always used a little over 10L/100 KM.

      I am speaking from personal experience when I say that with tyres, I am much more concerned with grip under wet road conditions than fuel usage.

      70

      • #
        Hasbeen

        So have I Truthseeker, you may have noticed they were replacing “performance” tyres.

        However my experience led me to these. When top name tyre companies stopped making performance tyres for 13 inch wheels, I went looking for something for my classic Triumph sports car. I did not want the “ditch finders” most imports in 13″ appeared to be.

        These were recommended to me for the Triumph by a tyre shop I respected. I did not expect much, & was very pleasantly surprised.

        Perhaps not quite as sharp on turn in, they are better than the French performance tyres they replaced in every other way. Better grip on damp or running wet roads, & every bit as good in the dry. They are quieter, better riding, & the steering is lighter, quiet an advantage in a non power steering car.

        I thus fitted them to the shopping trolley as well. This is a front drive trolley, not a proper car, & these tyres definitely out perform the cars suspension & dynamics in the wet.

        Of course as we all know, this is no longer of any real importance, as we are assured, with global warming, it aint gonna rain no more anyway.

        80

  • #
    David Jay

    The largest drag is from the turbulent air behind a vehicle, not from the high-pressure bubble around the front of a vehicle.

    As someone with a background in aerodynamics, I have always been amazed that designers make “aero” looking front ends (at the high pressure point), apparently for marketing reasons. Then they leave the back end (the low pressure area) flat and vertical.

    This is most visible with travel trailers (I think you call them Caravans down under?). Pretty, sloped front ends with completely vertical back ends.

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    • #
      David Jay

      Like this one here, for example:

      http://tinypic.com/r/npg8df/8

      30

    • #

      HI David,

      the nose on this train and other “bullet” trains are also the tails (one becomes the other when they go in the opposite direction).

      http://www.dailymail.co.uk/sciencetech/article-1363243/Hayabusa-new-luxury-186mph-Japanese-bullet-train-allows-passengers-travel-cabin-attendant.html

      Is this a compromise for aerodynamics to optimise both ends? Is the design more to optimise the tail than the nose?

      20

    • #

      Search the www for Kamm tail. Long-known. Widely used in passenger cars to a greater and lesser extent.

      Perhaps needs rediscovery by the popular media.

      Side-skirts on trucks are fairly common on trucks, but they still reduce their mobility; especially negotiating bumps, kerbs, etc.. Underbody turbulence and infiltration drag are significant for trucks on roads because they have substantial ground clearance. Nevertheless, fuel consumption is dominated by rolling (and climbing) resistance in heavy vehicles.

      Aerodynamic drag due to tail turbulence is relatively small and trying to minimise it reduces utilitiy and increases vehicle mass, resulting in increased rolling resistance. Truck speeds in most parts of the world are low; 100 km/h or less, and the aerodynamic drag doesn’t really come into play below 60 km/h; even for a big vehicle like a freight truck.

      The rolling resistance of roads is a more substantial factor. Rough roads increase fuel consumption 2- to 5-fold. Smooth, rigid tarmac without ruts provides the surface of least rolling resistance. Modern slap-dash roadbuilding that has become the norm in Australia of late allows for the early formation of ruts as well as providing high-frequency dips and rises from the outset; topped off by a rough surface. The visible surface is only part of the equation (PDF).

      Improving the nature of the roads improves the energy consumption of all wheeled vehicles, for all types of fuel and at all speeds, without modification to the vehicles.

      P.S. It seems that our host Joanne needs education on the difference between diesel and gasolene fuels. :-(

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    • #
      John Knowles

      I agree, a smooth tail/exit shape is more important. Perhaps trucks with large square tail sections could have an “inflatable breast” arrangement made from something like the Hypolon rubber of my white-water raft. It would only actuate at high drag velocity (80kph+) and might even double as a sort of rear impact air-bag.

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    • #
      Olaf Koenders

      The largest drag is from the turbulent air behind a vehicle, not from the high-pressure bubble around the front of a vehicle.

      Utter rubbish. If that were the case, bullets would be fired backwards. Everything that requires penetrative ease is pointy at the front.

      A knife edge
      Bullets/artillery shells
      Bullet trains
      Aircraft

      As far as I remember, the aero drag at the rear only equates to about 25 – 30%. Matters not if it’s a gas or solid, you can’t cut something with a dull knife.

      An episode of Aircrash Investigations showed how a 500km/h twin prop aircraft lost the rounded leading edge from one of its horizontal stabilisers and it lost all control.

      If trailing drag was the most significant as you say, it wouldn’t have crashed.

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  • #
    Yonniestone

    It’s proven technology that’s been known and tested for decades from aircraft to Bonneville Streamliners but the real world practicalities has always stopped public production, imagine in New York having 1 metre less spacing between cars in peak hour and there you have 1 km less useable road for every 1000 cars.

    This is just going to add another cost to running a road vehicle and even if it’s subsidized by some ‘green initiative’ then everyone pays, might as well slap on some solar panels, plop a hokey looking turbine on, throw some dead birds over your car, pay an extra $1 a litre with a sticker stating your socially responsible and we’re set.

    20

    • #
      Truthseeker

      Surely all this means is that sedans are more fuel efficient than SUV’s? You can have a functioning car without a square back end.

      20

      • #
        Yonniestone

        An interesting test was done on MythBusters to see if a Pickup truck or Ute in Australia was more fuel efficient with the tailgate up or down, of course it was better up as the tub creates a swirling vortex that the cabin air passes over smoother, I actually knew this in relation to speed in the 1/4 mile drags from years ago in a Ute I raced, it was worth 1/2 a second.

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  • #
    William

    I already have figured out how to get huge savings in my gas mileage.
    I would tether a half dozen greenies to the front of my car and have them pull it.
    Granted the acceleration would not be all that good at first, but I figure I could get it up to a reasonable level with a cattle prod.
    Similarly, if I lost traction in the snow, I could throw a couple of the greenies under the tires, and voila! Also the remains would do double duty as fertilizer next spring.
    Win, win all around.

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    • #
      Olaf Koenders

      Hopefully there are enough greenies to go around. Oh yeh.. silly me. The UN, Greenpiss University of Queensland etc. Should be enough to use some as snowchains as well.

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    • #
      NielsZoo

      Try dangling some organic carrots or a pre approved government Arts grant out in front of them on a pole, that should fix your acceleration problem.

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  • #
    William

    I already have figured out how to get huge savings in my gas mileage.
    I would tether a half dozen greenies to the front of my car and have them pull it.
    Granted the acceleration would not be all that good at first, but I figure I could get it up to a reasonable level with a cattle prod.
    Similarly, if I lost traction in the snow, I could throw a couple of the greenies under the tires, and voila! Also the remains would do double duty as fertilizer next spring.
    Win, win all around.

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  • #
    Mark A

    I generally don’t treat the “Mythbusters” programme anything but slightly entertaining but every now and then they come up with some good ideas.
    Watched the prog. about why dimpled golf balls travel faster and further than smooth ones? It has to do with drag and aerodynamics.
    Anyway they proved the principle works on a car as well, uniformly dimpled surface saved 13% fuel.
    Don’t think it will catch on though.

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    • #
      the Griss

      “uniformly dimpled surface saved 13% fuel.”

      We just need some decent hail storms.

      Oh look, another negative feedback. :-)

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      • #
        Mark A

        @the griss
        No, it don’t work like that it has to be dimpled all over not just the top.
        And I can prove it, after a sever hailstorm my Mazda station-wagon did look like a golf ball but only the top, the roof and bonnet and it didn’t improve my mileage at all.
        More the pity

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    • #
      JoKaH

      Yachties also discovered that special films that provided a dimpled surface on the hull also increased the speed of the hull by altering the boundary layer properties. This was pretty successful as can be seen by the fact that the International Sailing Federation rules now ban the use of “textured” surfaces for all yacht racing. They also tried special polymers to alter the boundary layer properties to help reduce skin friction and this has also been banned by the powers that be.

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    • #
      Yonniestone

      Dimpled surfaces would work well on a VW Golf, but the logistics of designing the giant clubs would be a nightmare. ;)

      Could be the big comeback of the ‘Woodies’ though.

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      • #

        Ohh dimpled cars like a golf ball. Nah that’d be no good, aim it to the left and it’d go to the right.
        It’d be almost impossible to get it to go in a straight line.

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        • #
          Yonniestone

          It would be the only instance where keeping your eyes down while driving will be a benefit, I could argue that this practice has been happening in my town for years.

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    • #

      For vehicles designed to have a laminar boundary layer past (approximately) the back window.

      Dimples have SFA benefit (if any) on the “compression” side and only really contribute ahead the leading edge of the “expansion” surfaces by introducing boundary layer turbulence. The turbulent boundary layer results in the mainstream laminar flow “seeing” a larger object so it will not “try” to expand towards the vehicle’s surface as forcefully. The power required to create the boundary layer turbulence is less than that which would be consumed in higher pressure drag.

      This is an aerodynamic property similar to the Coandă effect. (See also Le Chatelier’s Principle.)

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      • #
        Olaf Koenders

        Agreed. Golf balls only have all over dimples because of their usage requirements. I wonder what would happen to ping pong balls if we incorporated that somehow..

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  • #
    u.k.(us)

    RE: that last pic.
    A friend of mine drives for Fed-Ex in Chicago, he said he gets in big trouble if he rips off those trailer skirts while trying to navigate through piles of snow in poorly plowed loading docks.
    He’s a city driver, never gets up enough speed to make them effective.
    Makes sense on the highways though.

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    manalive

    Shades of ‘30s auto design, for instance the Tatra 87.
    Wiki says: “… Thanks to aerodynamic shape it has a consumption of just 12.5 liters per 100 km …” which wasn’t bad for the period.
    Driving it did require some experience and finesse though:
    “… After the 1938 invasion of Czechoslovakia by Nazi Germany, Tatras continued in production, largely because Germans liked the cars. Many German officers met their deaths driving heavy, rear-engined Tatras faster around corners than they could handle. At the time, as an anecdote, Tatra became known as the ‘Czech Secret Weapon’ for the scores of officers who died behind the wheel; at one point official orders were issued forbidding German officers from driving Tatras …” (Wiki).

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  • #
    Hasbeen

    If you want to reduce drag, just forget all this stuff about tailgating being bad.

    I once held 4Th place in a major formula 1 race at Warwick Farm, in an 1100cc pushrod formula junior. I managed to get into 4Th off the grid, & tucked in tight behind the three leaders, in their slipstream. I was getting 160 MPH on half throttle, in a car that could not exceed 139 down that straight when alone.

    On the 4Th lap the second car lost a few feet on the front car, & the hole in the air was no longer strong enough for me & I lost the tow. 2 of the 8 Formula 1s behind me, than caught & passes me, 3 never caught me, & 3 others broke down before they could. Formula racing in the 60s.

    I was also timed down the straight at Bathurst in 64, in a Hillman Imp at 107 MPH. By it self the Imp could not make 80 MPH, but a mate in a Triumph 2000 accelerated very gently out of Forrest Elbow, so I could stay with in inches of his tail, & thus towed me up to 107.

    So how about the motto, “tail gate for the future of humanity”. Is it any more ridiculous than using windmills?

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    • #
      JoKaH

      When racing Formula Vees it was an established fact that if you led at the start last lap you probably wouldn’t win as the slipstreaming ‘congo line’ of cars behind you would let you make the hole in the air and pull out and pass just before the finish line. Slipstreaming also enabled the Formula Vees to touch 200kph on Conrod.

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      Yonniestone

      ‘a Hillman Imp at 107 MPH’ a statement I thought would never be made in this reality, kudos to your elephantical gonads for even attempting this.

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      • #
        Hasbeen

        It made the front page of the Sydney Morning Herald the next morning Yonniestone.

        I often used to wonder how many young hoons rushed off & bought one of these hundred mile per hour Imps, only to suffer a dose of reality.

        No histrionics at all from the Imp, it just trundled along behind the Triumph.

        100MPH was not such a big deal back then, it was quite legal on the public road. In fact, on those long straights on highway 1 in Victoria, if you were ONLY doing 100 MPH in the early mornings, you would be getting passed by the semitrailers on the overnight run to Melbourne.

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    • #

      Car makers like Volkswagen have, for decades, been working on “telematics” that facilitate slipstreaming on high speed roads. Instead of relying on human reaction times and perception, the cars communicate their behaviour and “intentions” to those joining in the line.

      Besides the regulatory/legal issues, there are inherent, technical problems with scalability. The number of vehicles in a line is limited; before a disturbance (“perturbation”) has the potential to produce “chaotic” responses in the vehicles following. Inherent technical problems are the perfect world of professional researchers.

      Don’t get me started on autonomous crashcars.

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      • #
        Yonniestone

        Autonomous cars are just an upmarket form of public transport the difference being you get to park the train/bus at home and maybe even allowed to drive it in certain areas under certain conditions for a fee of course, a green bureaucrats wet dream.

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    • #

      Hasbeen (err, Phil)

      I was also timed down the straight at Bathurst in 64, in a Hillman Imp at 107 MPH.

      I bet you wish you had entered one of those Vauxhall Vivas instead of the Hillman, eh!

      Tony.

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      • #
        Yonniestone

        I learnt how to drive in a 1968 Hillman Hunter Safari Wagon, it was the smoothest 4 speed gearbox I’ve driven to this day.

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        • #
          Ron Cook

          Yonniestone,

          My Dad had a Hillman Hunter circa 1967ish. 4 on the floor, lovely car to drive. A Hunter won the London to Melbourne (or was it Sydney?) race somewhere round that time.

          R-COO- K+

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      • #
        Hasbeen

        Yes Tony, 1100cc against 875cc. They had about 200 yards on us up mountain straight, & we could only get 175 yards of it back around the rest of the circuit.

        I didn’t have much say in what I was driving Tony. Routes offered me an Imp, the general didn’t offer me a Viva. It wasn’t until the Monaro that the general offered me a car.

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        • #

          It wasn’t until the Monaro that the general offered me a car.

          The first HF-500, and second place too, even with a NZ co-driver!

          Beaten only by tyre choice, eh! Who would have thought of using road tyres.

          Did you ever race open wheelers at Surfers?

          Tony.

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          • #
            Hasbeen

            Yes the gold star race in 68. in the BT23 Brabham Repco. That corner under the bridge was incredible in an F1.

            I was sitting just behind Leo Geoghegan, wondering if I could take him, when a conrod came out the side of the Repco engine.

            I couldn’t believe it when I found out the mechanics had dropped the sump, undone the big end bolts, & inspected the slippers, with out replacing them. With the crush gone, the slippers turned in one rod, closing the cylinder oil spray hole off, & the piston seized.

            Still it wasn’t my car, so I had no say in maintenance.

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            • #
              The Backslider

              Dang those mechanics!

              We once had some mechanics use after market filters on a Case 9380 which was still under warranty.

              It threw a rod out the side. The Case guys inspected it and found a filter had disintegrated and fouled the oil system.

              “Sorry guys, but no warranty on that one”.

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    • #
      jorgekafkazar

      I owned an Imp (marketed as Sunbeam, here). Nice little CC engine, but the rest of the car was junk. I was planning to convert it to alcohol, but gave up as soon as I got a closer look at the chassis.

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  • #
    handjive

    This is the correct way to burn fossil fuels in a car ….

    [HOONIGAN] KEN BLOCK’S GYMKHANA SEVEN: WILD IN THE STREETS OF LOS ANGELES

    https://www.youtube.com/watch?v=5qanlirrRWs#t=351

    Yeeh-Hah!

    (via Tim Blair)

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  • #
    Roger

    In the EU car manufacturers work to reduce fuel consumption and the ‘deadly’ CO2 emissions….

    What consumers find though is that the fuel consumption figures they can achieve typically bear little or no resemblance to the published figures from the standardized EU test.

    The Fiat 500 released earlier this year is a classic example of where it can all go badly wrong and this was recently exposed on ‘Watchdog’, a BBC consumer programme in the UK. The Fiat engine has been set up to minimise fuel consumption and CO2 emissions to such an extent that people who have bought them find it will not go up hills!

    Even one of Top Gear’s past Stigs was unable to drive it around the hilly streets of Bristol. Trying to start off on a slope needed the engine revved to 6000 rpm and the clutch slipped to get the car to move forwards rather than stall , and even then sometimes it worked and sometimes it didn’t.

    Fiat, who had been denying there was any such problem, eventually accepted there is and have now said that they will be taking steps to rectify it.

    Too many cars nowadays are designed and set up to achieve low fuel and emission ratings in the artificial tests laid down by the EU but the way they are set up means that in every day driving they will consume more fuel than earlier versions. Typically this is because of the current higher gear ratios and lower power settings which require more fuel to produce an acceptable and safe performance for the average driver in everyday driving.

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    • #
      Olaf Koenders

      Yup. Top Gear got a Prius to lead foot it around their track tailed by a 5L BMW. The Prius sucked way more fuel.

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  • #
    Alan Poirier

    I think we ought to contact Kim Kardashian to lend a hand with PR. There is an uncanny resemblance….

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  • #
    Aaron M

    If only boat tail bullets would return a 25% grouping improvement at the rifle range. I get about 2% on a few calibres.

    Still, maybe it will help land Australia Post parcels 25% more acurately :)

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  • #
    TinyCO2

    Some of these ideas are already being used in the UK too. The picture roll at the top of this page show a good selection of how they are implemented. M&S expect to save 20% on fuel.

    http://www.donbur.co.uk/eng/news/articles/060913_mands_teardrop_trailer.php

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  • #
    Another Ian

    Jo,

    On another front and much easier to apply imo.

    Check out the Watsilla Suzler container ship engine.

    Now you’ll have trouble fitting that as a repower in your Mini, but it is pushing 50+% efficiency.

    So it should be possible to do such with the common garden vehicles we deal with which aren’t near this efficient.

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  • #
    Byron

    The problem with streamlining the rear of passenger vehicles is that it reduces stability at speed , especially on uneven road surfaces. Drag at the rear of the car assists in keeping it pointed to where it should be , i.e. opposite to Your direction of travel . The most recent example that I can think of is the Audi tt 1.8 which was very aerodynamically efficient but under certain conditions the bum of the car could step out and and once this happened it wanted to keep going until it was leading the dance , this resulted in the car being recalled and modified with a tiny spoiler fitted to the rear .

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    Anton

    Various problems with this: for container-carrying trucks the tail has to be attached from the container at the start of the journey and detached at the end, while for non-container trucks the tail makes it harder to load (which is done from rear doors). Also there is a limit on the length of articulated trucks that is determined by the geometry of urban road junctions, and if some of that length is taken up by the tail then the truck will be able to carry less, so that more trucks are actually needed on the road to carry the same quantity of goods…

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  • #
    Gaz

    In lhe 1960′s I used to own a Citroen ID19 which had a tail like that, a long streamlined nose and a fully skinned underside and it got up to 45 miles per gallon. It was a big car (I once got 15 people in it at Uni) and the manual said the most economic speed was 70 miles per hour (around 120kph).
    Everything old is new again.

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  • #
    Andrew McRae

    Speaking of efficiency, I believe the Brisbane City Council has obtained the most effective energy-saving carbon footprint minimising lights in the world.

    As has become typical at this time of year, a giant Christmas tree has been erected in the middle of Brisbane’s CBD at King George Square. The council has for several years built this as a homage to Gaia in true eco-mania style by advertising that the lights on the Christmas tree are “solar powered”.
    There is apparently just one little problem with this arrangement, which you might figure out from this photo taken at just 7:20pm this evening.
    These renewables are great for saving energy and CO2 emissions aren’t they?

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    • #
      Annie

      Hmm. I foolishly bought a mini solar-powered Christmas light set; really for the enjoyment of the children next door. I’ve had the panel ‘charging’ for the last few days and ‘turned on’ the lights. Not the tiniest flicker of light. Guess which set will be returned to the shop next time I’m in town?

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      • #
        Robert

        I put a solar powered light out front to illuminate the flag at night. Even in summer with full sun for over 10 hours to charge the battery the thing couldn’t make it through the night. It’s in the garage somewhere for parts for some as yet to be determined future project. Hardwired a lamp into the GFCI circuit out front and put a light sensor on it to turn it on at dusk off at dawn. That one keeps the flag lit up all night regardless of temperature and weather.

        Now the solar panels on my weather station and the one up on the repeater for the anemometer do what they are supposed to, they power the rig during daylight with a trickle feed to the batteries which take over once the sun is no longer “energizing” the panel. Of course both the electronics on the station, including the fan to move air past the hygrometer, and the electronics for the anemometer repeater are very low current loads so even when the temperatures are in the negatives they work fine.

        Have yet to have any solar powered lighting that, on a full charge during one of longest summer days with crystal clear weather, will stay illuminated all night. And if it can’t do it in summer it certainly isn’t going to make it in winter.

        Were your Christmas lights LED too? Just curious as it would not surprise me if they were in a series configuration where one bad bulb means no lights at all. Most of the AC powered lighting strings I run across work that way regardless of bulb type. While I wouldn’t expect the solar ones to stay lit all night, they should have at least worked.

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      Andrew McRae

      In the interests of “correcting the record”, I feel compelled to announce that the lack of lighting in the above linked photo was not due to flaky solar power. The official switching on of the Christmas tree lights did not take place until Friday night. Ah well, it was fun while it lasted.

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  • #
    Hasbeen

    A couple things the technical may find interesting on drag & fuel consumption.

    In 63 I raced my new Morgan +4 at Bathurst. It was developing 79 BHP at the wheels, at 4800 RPM. It was timed at 124.4 MPH through the flying 1/8Th.

    In 64 I again raced it at Bathurst after quite a bit of power development work. It was then developing 115 BHP at 4800 RPM. It this trim, with 45% more power it did 124.6 MPH. I assumed this was due to it’s lack of aerodynamic shape, hit a brick wall of air at this speed, although it could have been it ran out of breathing at 6250 RPM.

    The more surprising statistic was fuel consumption. Apart from the Hillman Imp, every car I raced at Bathurst, including the Morgan, a couple of Formula junior & formula 2 cars, [1100 & 1500cc cars with from 110 to 160 BHP, the Holden Monaro, & a Ford GT HO, a few other touring cars & even the formula 1 Brabham Repco all gave within a whisker of 7 miles/gallon.

    I only discovered this recently, when a friend asked for some figures. It really amazed me

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  • #
    Ben Vincent

    What is the potential problem with all this?
    It makes each vehicle longer with more overhang.
    Maneuverability is reduced.
    And fewer vehicles fit in a given space.
    In other words, traffic flow will decrease.
    Won’t be saving much gas when you are stuck in traffic with all the engines idling, wasting fuel.
    The vehicles won’t be able to make turns at intersections either. The streets aren’t wide enough.

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    • #
      Ron Cook

      B V

      “Won’t be saving much gas when you are stuck in traffic with all the engines idling, wasting fuel.”

      Ah! some modern cars automatically switch off the engine when coming to a stop which I found out to my suprise and frustration on a recent trip to France. The car restarts when you lift your foot off the brake.

      At first I thought the hire car, a Toyota SUV (don’t know the model) had a fault until it dawned on me what was actually happening. Don’t know what it does for battery life tho’.

      R-COO- K+

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    Mark D.

    Wouldn’t there be another worthwhile advantage of having trucks with pointy noses? Lower fatalities from head-on collisions?

    10

    • #
      NielsZoo

      They’re called “cow catchers” here in the States and used to be standard equipment on steam locomotives. The prevented fatalities on the train… the cows and buffalo, on the other hand, didn’t fair so well. Smashed, or flipped and rolled… neither one is much good for you and these teeny little cars our governments are forcing us into ain’t gonna fair much better than the cows.

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      • #
        Rod Stuart

        Each winter about 75 moose meet their maker on the Canadian National rail line between Edmonton Alberta and Prince George British Columbia. Some of these are bulls in rut who will challenge anything……..anything at all.

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    Gary

    Market it as more trunk room.

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    Richard deSousa

    Stupid idea!! Where will we store the luggage if we’re going on a trip???

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    The Backslider

    OT – Looks like all that melting is causing really thick ice. Who woulda guessed?

    http://www.gizmodo.com.au/2014/11/this-robotic-submarine-found-that-arctic-ice-is-thicker-than-we-thought/

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  • #
    ramspace

    What about Airtab drag reduction devices? They’re cheap, easy to install, and offer a modest improvement in mileage. The company also claims they improve trailer stability. Perhaps it’s all just moonshine, but it seems to offer that elusive goal: something for nothing. (http://www.airtab.com/)

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    handjive

    Goin’ O/T:

    The Queensland Government wisely IGNORES the BoM …

    Remember back to 2008, when the BoM squealed “This Drought May Never End”?
    “Perhaps we should call it our new climate,” said the Bureau of Meteorology’s head of climate analysis, David Jones.
    http://www.smh.com.au/news/environment/this-drought-may-never-break/2008/01/03/1198949986473.html

    “El Niño was to blame” said David Jones.
    http://www.theage.com.au/national/drought-and-fire-here-to-stay-with-el-ninos-return-20090216-899u.html#ixzz1nrZUq1ik

    The deadly, unpredicted Brisbane Floods of 2011 was the result. 35 dead.
    http://en.wikipedia.org/wiki/2010–11_Queensland_floods#Deaths

    Fast forward to 2014, the BoM, with a 90% degree of confidence predicts a hot, dry El Niño for Summer:
    “With a 90% chance of the global weather phenomenon striking this year, impacts both devastating and beneficial will be felt from India to Peru”
    http://www.theguardian.com/environment/2014/jun/11/-sp-el-nino-weather-2014

    The Queensland Government …
    26th Nov 2014
    Early-release strategy for Wivenhoe Dam to prevent flooding

    http://www.qt.com.au/news/early-release-strategy-wivenhoe-dam-prevent-floodi/2465728/

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    Leo G

    At any instant the vehicle energy losses due to viscous drag are proportional to the square of vehicle road speed. One strategy to improve overall efficiency would be to dramatically reduce the operating speed of all trucks while increasing their number in inverse proportion to the proportional speed change.
    Impractical of course on a public road shared with other vehicles, but worth considering on dedicated ” roadways”, particularly if that facilitates autonomous vehicles.

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    • #

      At any instant the vehicle energy losses due to viscous drag are proportional to the square of vehicle road speed.

      As I’ve indicated (and referenced to test data) above, the main energy requirements for moving large trucks are due to rolling resistance and climbing resistance; the latter being when the truck is effectively lifting its weight up the side of a hill/mountain.

      Rolling resistance is largely independent of vehicle speed. Its resisting force is proportional to the weight of the vehicle (mass × gravitational acceleration) with “fixed” parameters such as vehicle tyre and road surface characteristics; as addressed earlier.

      The motive energy requirements for moving a given load only depend on the distance that the load is moved. (Basic physics: Work is force multiplied by the distance of which it is applied.)

      i.e. nothing is saved by making the vehicle slower; just more lives wasted.

      To save energy use in long-haul road transport (and everybody else); build rigid, smooth set surfaces into highways. That can better than halve the fuel consumption compared to “standard” highways in Australia. It’s where our fuel taxes/excise should be being directed.

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    Lank is coned

    Been around before Jo! – Beldar Clorhone and his life mate Prymaat came up with the idea. Beldar worked as an appliance repairman but there was clearly cone aerodymamics firmly implanted in his head before he got that job!

    I’m sure the cone shape has been used on other planets.

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    Neville

    This is O/T, but I hope everyone and particularly Jo and David will have a look at this latest high resolution proxy data from Steve McIntyre.
    This should set the cat among the pigeons.
    BTW the oft quoted Moberg et al study backs this up when it is turned up the correct way. Go Steve.

    http://climateaudit.org/2014/11/25/new-data-and-upside-down-moberg/#more-20283

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    pat

    woke up to a lengthy item about the following on ABC News Radio this morning:

    27 Nov: ABC: Stephanie Small: Polar bears could face starvation by the end of the century, scientists say
    Dr Andrew Derocher from Canada’s University of Alberta said the region’s icy conditions were crucial for polar bears, but sea ice projections in the area were not positive…
    Dr Derocher said up to a quarter of the world’s polar bears could lose their habitat and the decline would happen “quite quickly”..
    http://www.abc.net.au/news/2014-11-27/polar-bears-could-face-starvation-by-end-of-century/5920802

    thought it sounded familiar:

    oh, ABC & MSM worldwide, including SBS, Sky Australia, etc, had reported this about 10 days ago:

    Study: Polar Bears Disappearing From Key Region
    ABC News-17 Nov 2014
    (links to the study by) Jeffrey F. Bromaghin, Trent L. McDonald, Ian Stirling, Andrew ***Edward Derocher***…etc

    anthony had even done a thread debunking the MSM sensationalism on 18 Nov:

    WUWT: Study: Beaufort sea polar bears largely recovered from a 2004-2006 decline
    All the media headlines (e.g. The Guardian) have followed the press release lead and focused on the extent of the decline. However, it’s the recovery portion of the study that’s the real news, as it’s based on new data…
    The title of the new paper by Jeffery Bromaghin and a string of polar bear biologists and modeling specialists (including all the big guns: Stirling, Derocher…etc
    http://wattsupwiththat.com/2014/11/18/study-beaufort-sea-polar-bears-largely-recovered-from-a-2004-2006-decline/
    COMMENT by toorightmate: You will not believe this, but in Australian tonight (1027 hours GMT to be precise), the Brisbane Courier Mail newspaper posted a “Breaking News” headline which said:-
    “Study: Polar Bears are Disappearing”.
    Unfortunately about 2 million Queenslanders will read that tomorrow and believe it.
    Only about 50 Queenslanders will read this post on WUWT.
    We still have a long, long way to go in the propaganda battle.

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    pat

    re the polar bear study, at least CAGW-infested CBC noted the following criticisms:

    3 Sept: CBC: Reg Sherren: VideoPolar bears: Threatened species or political pawn?
    The reported decline of polar bears is under question
    The Polar Bear Specialist Group, a group that Derocher once chaired, estimates that globally there are up to 25,000 bears in the whole Arctic, with about two-thirds of those in Canada. It identifies at least four Canadian sub-populations in decline…
    Polar bears are not in trouble at the moment
    Biologist Mitchell Taylor has studied polar bears and advised governments for more than thirty years, living in the high Arctic for much of that time.
    “They’ve certainly been around through the last interglacial period,” says Taylor. “During that interglacial it was warmer than it is now: we had pine trees on Baffin Island, deciduous forests north of the Arctic Circle. Polar bears had to have survived that or we wouldn’t be seeing polar bears now,” he says…
    He says that many of the current estimates are based upon a lacking methodology, admitting that some of his previous work incorporated the allegedly faulty technique as well…
    In 2008, he signed the controversial Manhattan Declaration on climate change, which argued that there was no conclusive evidence that carbon dioxide emissions from modern industrial activity was causing catastrophic changes in global climate.
    “There was only one perspective, and that was what was provided by the IPCC,” says Taylor.
    Taylor says that because he lived in the north he had direct contact with the people in the area, giving him a unique perspective on what was really happening on the ground.
    “What they were describing was quite simply inconsistent with what I was hearing from local people, what I was seeing myself.”…
    When Taylor made his thoughts known, he says he expected a free exchange of ideas or at least a healthy scientific debate. Instead he says he was ostracized inside the polar bear scientific community.
    “I’ve known those guys for like 20 years. They know me, they know I would never say or do anything to harm polar bears deliberately,” he says.
    Indeed, Taylor is not alone in his assertion that polar bear numbers are at a healthy level. Just last year Environment Canada reported that “The polar bear does not have a small wild population, it does not have a restricted area of distribution and no marked decline has been observed.”…
    Taylor: “In the end nature will speak and it will be clear who knew what they were talking about and who didn’t.”
    http://www.cbc.ca/news/technology/polar-bears-threatened-species-or-political-pawn-1.2753645

    also worth noting the following, plus updates on Crockford’s homepage:

    2 Nov: PolarBearScienceBlog (Susan Crockford): Polar bear biologists doing mark-recapture work in Hudson Bay may have misled the world
    Andrew Derocher (University of Alberta) and several of his students (including Patrick Mislan shown above), Nick Lunn (Environment Canada), and conservation activist organization Polar Bears International (led by former USGS biologist Steve Amstrup) have all been doing invasive research on WHB polar bears using mark-recapture methods over the last 10 years but none of the data on body condition, cub survival and litter sizes have been published.
    Remember this when you hear and read statements from these biologists and other conservation activists over the next few weeks and months…
    http://polarbearscience.com/2014/11/02/polar-bear-biologists-doing-mark-recapture-work-in-hudson-bay-may-have-misled-the-world/

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    janama

    O/T – this morning I decided to revisit mornings with Linda Mottram on ABC 702. Fist up was an interview with Bernard Keane who with Helen Razer has just released a book titled – A Short History of Stupid: The decline of reason and why public debate makes us want to scream.

    His two examples of stupid were people who objected to vaccination and – you guessed it – climate deniers. no one challenged him……sigh.

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    pat

    Liberal Democrats Senator David Leyonhjelm is all over our MSM today….but not because of his “coal is king” remarks below, which only makes an ABC RURAL report. i have not found it anywhere else.
    (what the MSM is carrying from the TV channels, to News Ltd., to Fairfax, Guardian, ABC/SBS, etc is a Leyonhjelm same-sex marriage story):

    27 Nov: ABC Rural: Babs McHugh: Senator David Leyonhjelm declares ‘coal is king’ as he launches attack on anti-coal activists
    Liberal Democrats Senator David Leyonhjelm has launched a spirited defence of the coal industry in an address to the Senate which he says voiced the thoughts of the silent majority.
    In the address, Senator Leyonhjelm describes anti-coal activists as an ‘economically illiterate minority who have lost the plot’.
    “This is for the many Australians who are the silent majority in the debate about the value and benefits of coal to this country,” Senator Leyonhjelm said.
    “I think it is time to acknowledge the 55,000 men and women employed in the Australian coal industry and keep the lights on.
    “I’d also like to thank the coal industry itself for the $6 billion in wages paid to those workers.
    “Coal is our second biggest export, earning $38 billion in 2013.
    “The coal industry directly provided $3.2 billion in royalties to state governments, and $10 billion more in company and employee taxes.
    “That money pays for schools, hospitals, pensions and all the other services we expect governments to provide”.
    Senator Leyonhjelm says coal has underpinned the Australian economy and high standard of living, and will do the same for the 1.3 billion people who currently have no access to cheap energy…
    “For many of these people, their days are spent unproductively gathering firewood and animal dung for heat and cooking and washing.
    “The world’s biggest democracy, India, has 300 million people who have no access to electricity at all.”
    The International Energy Agency has recently released the Global Energy Outlook 2014 in which it says coal use will grow until 2040 and then plateau.

    Low emissions energy will outstrip coal sooner rather than later: sustainability specialist
    Jemma Green, a Fellow at the Curtin University Sustainable Industries Institute in Western Australia, is also a representative of the Carbon Tracker Initiative, which has the stated aim of ‘shifting the financial markets system towards supporting a low carbon future’.
    Ms Green says the global market for coal is changing much more rapidly than many people, including Senator Leyonhjelm, recognise….AND ON AND ON AND ON AND ON
    http://www.abc.net.au/news/2014-11-26/senator-leyonhjelm-defends-coal-in-the-senate/5919972

    ABC gives “sustainability specialist” Jemma Green 13 paras to put down coal, while the Senator gets 11, roughly speaking!

    LinkedIn: Jemma Green, Research Fellow, Curtin University, Renewables & Environment
    Founding Board Director
    Future Super
    February 2014 – Present (10 months) Perth, Australia
    Ambassador, 1 Million Women
    Managing Director, The Green Enterpise
    Advisory Board, Carbon Tracker
    Honors & Awards
    Scholarship
    Cooperative Research Centre for Low Carbon Living
    Scholarship CSIRO
    Organizations:
    Member, Responsible Investment Association Australasia
    Opportunities Jemma is looking for:
    Joining a nonprofit board
    Publications
    Embedding Environmental Risks in Finance: Current Methods and Ongoing Challenges(Link)
    The Journal of Environmental Investing
    September 2011
    Education:
    International Teaching Seminars
    ***Master Practitioner in Neuro Linguistic Programming, Master Practitioner in Neuro Linguistic Programming
    2009 – 2010
    http://au.linkedin.com/pub/jemma-green/4/11a/b76

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      the Griss

      “sustainability specialist”

      ROFLMAO..!

      Bet she has never studied biology.

      And doesn’t realise that to work towards real sustainability,

      THE EARTH NEEDS MORE ATMOSPHERIC CO2.

      Yes we should be controlling REAL pollution.

      But CO2 is NOT POLLUTION ………

      CO2 is a vital part of the carbon cycle that SUSTAINS all life on Earth..

      .. and atmospheric levels of CO2 need to be pushed up, NOT down.!!

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    pat

    for jemma green – nothing NLP about this:

    26 Nov: Reuters: Yuka Obayashi: Japan’s coal consumption to stay near record highs next year – think tank
    Japan’s total coal consumption is likely to stay near a record high next year as a prolonged shut down of nuclear plants and a softer economy prompt power utilities to stock up on the cheaper fuel, a government-affiliated energy research institute said.
    The continued high demand from the world’s second-biggest coal importer will support a depressed mining sector, but could make Japan a target for criticism at United Nations climate talks next year as coal is one of the dirtiest fuels for generating electricity…
    Even if the first reactors return next year, analysts say utilities in the country would cut their use of more expensive fuel oil, crude and natural gas before coal…
    Thermal and coking coal consumption soared to a record of 194.2 million tonnes last year as utilities moved away from expensive fossil fuels to cut costs.
    Japan, which unexpectedly slipped into recession, gets about 30 percent of its electricity from coal and analysts do not expect consumption to come down any time soon…
    http://uk.reuters.com/article/2014/11/26/japan-coal-consumption-idUKL3N0TF2VJ20141126

    and no phony US/China climate deal will alter the following:

    13 Oct: Reuters: Coal to surpass oil as top global fuel by 2020 -Woodmac
    by Florence Tan, Meeyoung Cho and Jane Chung
    Coal, propelled by rising use in China and India, will surpass oil as the key fuel for the global economy by 2020 despite government efforts to reduce carbon emissions, energy consultancy firm Wood Mackenzie said on Monday.
    Global coal consumption is expected to rise by 25 percent by the end of the decade to 4,500 million tonnes of oil equivalent, overtaking oil at 4,400 million tonnes, according to Woodmac in a presentation at the World Energy Congress.
    The two Asian powerhouses will need the comparatively cheaper fuel to power their economies, while demand in the United States, Europe and the rest of Asia will hold steady.
    “China’s demand for coal will almost single-handedly propel the growth of coal as the dominant global fuel,” said William Durbin, president of global markets at Woodmac. “Unlike alternatives, it is plentiful and affordable.”
    China – already the top consumer – will drive two-thirds of the growth in global coal use this decade. Half of China’s power generation capacity to be built between 2012 and 2020 will be coal-fired, said Woodmac…
    China has no alternative to coal, with its domestic gas output limited and liquefied natural gas (LNG) imports more costly than coal, Durbin said.
    ***”Renewables cannot provide base load power. This leaves coal as the primary energy source,” he said…
    “The struggling economy and low coal prices has rendered the European Union (EU) Emissions Trading Scheme (ETS) ineffective,” Durbin said. “The carbon price will need to reach 40 euros per tonne to encourage fuel switching, which is unlikely before 2020.”
    In Southeast Asia, coal will be the biggest winner in the region’s energy mix. Coal will generate nearly half of Southeast Asia’s electricity by 2035, up from less than a third now, the International Energy Agency said in early October.
    This will contribute to a doubling of the region’s energy-related carbon dioxide emissions to 2.3 gigatonnes by 2035, according to the IEA.
    http://www.reuters.com/article/2013/10/14/coal-demand-idUSL4N0I202320131014

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    pat

    back in australia, anti-coal insanity continues:

    27 Nov: BusinessSpectator: Andrew Herington: Victoria at a fork in the road on energy
    (Andrew Herington is a former Labor ministerial adviser now a Melbourne freelance writer who has worked with community groups opposing the East West Link)
    The Victorian Greens have tried to press their credentials by outbidding everyone and promising to close the entire brown coal sector by 2023. The extreme plan to shut 2200 megawatts within 12 months (Anglesea, Hazelwood and part of Yallourn W) stretches credulity and highlights the position the Greens have taken as idealists on the sidelines.
    The improbability of their claim that the remaining coal powered stations could be scrapped in just eight years has meant the policy has been widely ignored. These are the sorts of goals that might be achievable by 2040 but the immediate challenge is to reduce brown coal from a 95% market share to something south of 75% by 2020.
    ***If, as is quite possible, the Greens have the balance of power in the upper house (Legislative Council) they will need to find more practical incremental policies to leverage their influence…
    http://www.businessspectator.com.au/article/2014/11/27/policy-politics/victoria-fork-road-energy

    Fairfax is also carrying the following -
    (see The Age: Stephen Cauchi: Coal not the panacea for poverty)

    25 Nov: BusinessSpectator: Staff Reporter: Citi doubts coal’s ‘energy poverty’ claim
    Citi’s Elaine Prior said in a report that “a variety of clean energy technologies” will play a significant role, while some developing nations were taking an “everything but coal” approach.
    “Despite coal industry assertions that coal is required to lift developing nations out of energy poverty, we suspect that a variety of cleaner technologies will play a substantial role,” she said.
    Citing the International Energy Agency’s most recent energy outlook update, she said coal was playing a minor role in Africa compared to hydro, gas, renewables and mini-grid/off-grid systems…
    Furthermore, the investment bank analyst said the US-China deal had put risk to thermal coal demand and trade on the downside, with Australia set to bow to the international push for carbon pricing eventually.
    “Assuming continued international progress with development of carbon pricing schemes, we suspect that Australia will revert to carbon pricing eventually, perhaps under different political leadership,” she said.
    http://www.businessspectator.com.au/news/2014/11/25/energy-markets/citi-doubts-coals-energy-poverty-claim

    about Citi’s (Citibank) Elaine Prior from this Conference website:

    Australia’s Sustainability in Business Conference: 7-8 October 2015, Melbourne – Contributor
    Elaine Prior
    Job TitleDirector / Senior Analyst
    Company Name Citi Research
    About
    Elaine Prior is a Director / Senior Analyst, at Citi Research in Sydney. She is responsible for ESG/sustainability research for Citi’s fund manager and superannuation fund clients…
    She has a Bachelor of Science (Hons) in Chemistry (Bristol, UK) and a Master of Science (Dist) in Petroleum Engineering from Imperial College, London. She previously worked as an engineer in the oil industry in the UK North Sea and Australia. In 1999, she undertook a degree in Antarctic Studies at University of Tasmania (for fun!), gaining an enhanced appreciation of climate change science, and then worked briefly on environmental projects relating to Antarctic and Arctic tourism.

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      Hasbeen

      If Labor win, wouldn’t it be wonderful if the Greens can pull it off, & shut down Victoria’s power.

      After all it would only be Victorians suffering, & they would deserve it if they are silly enough to put them back in. It would spell the total destruction of any credibility they or wind power may have with the gullible. What huge own goal, & a win for the real people.

      Bring it on, please.

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    pat

    26 Nov: DomesticFuel.com: Joanna Schroeder: Global Investment for Climate Change Falls Again
    According to a new report from Climate Policy Initiative, global investment in activities that reduce the threat of climate change fell for the second year in a row from USD $359 billion in 2012 to USD $331 billion in 2013. The report, “Global Landscape of Climate Finance,” found while public sources and intermediaries contributed $137 billion, private investment dropped by $31 billion (all numbers USD).
    The International Energy Agency (IEA) estimates that an additional $1.1 trillion in low-carbon investments is needed every year between 2011 and 2050, in the energy sector alone, to keep global temperature rise below two degree Celsius. In other words, the world is falling further and further behind its low-carbon investment goals.
    Climate finance spending was split almost equally between developed (OECD) and developing (non-OECD) countries, with $164 billion and $165 billion respectively. Nearly three-quarters of all spending was domestic: It originated in the country in which it was used. Private actors had an especially strong domestic investment focus with $174 billion or 90 percent of their investments remaining in the country of origin. These figures illuminate a bias by private investors toward environments that are more familiar and perceived to be less risky
    http://domesticfuel.com/2014/11/26/global-investment-for-climate-change-falls-again/

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    jorgekafkazar

    There are important aspects of the “strap-on” fairings that can be dangerous. A land world’s speed record car many years ago went slightly sideways and tore a thin support strap, opening the cone to slipstream air. Suddenly, the car was whipped around and lost traction, rolling over and over. The driver was killed. Add-on fairings must be designed for all load conditions.

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    Rud Istvan

    There are many aerodynamic tricks for class 8 trucks (tractor/trailor)–I know as sometime ago the head of marketing and product development for Navistar.
    Joanne’s illustrated trailor boat tail is exactly 5 feet long (you can guesstimate the dimensions from the standard size class 8 tires). That is because the maximum trailor length in the US is exactly 53 feet by law. So you can add a 5 foot boat tail to the previous maximum, 48 foot. But every such tractor trailor loses 48/53 of cargo capacity. In almost all circumstances, the lost revenue is greater than the resulting fuel cost savings. So the add on is not much used, although available for many years.

    Another, better example. By moving the fromt axle back about 18 inches ( necessitating new front end steering and shock engineering at a cost of $16 million in the 1980′s), we could put on a front end underside airfoil (reducing under chassis turbulent drag at 100kph) that gained 6% fuel economy. Sold the truck as the 9600; saving about $4000 per vehicle over the 4-5 year long haul life. (After that first about 500,000 miles, maintenance issues relegate almost all class 8 tractors to short haul routes at lower average speeds where the savings are negligible.) But no more such easy aerodynamic picking remain. What, truck manufacturers are not sensitive to and necessarily responding to customer desires. They have been at it for several decades.

    Biggest customer issue with the 9600 was that we had to reverse the driver door opening (forward, not rear) in order to accomodate the new driver step placement. Many drivers felt that was ‘unnatural’, and recruiting good drivers ( no leadfoots, proper shifting..) had a bigger impact on fuel economy than our measly 6% aerodynamics…So a disappointing uptake for the first couple of years.

    The world is a big complicated place. The details of boat tail truck history triggered by this post just illustrate that nicely. Regards all here, and hope some might enjoy some of the new Blowing Smoke essays. This thread could have been one, although a bit arcane compared to polar bears or temperature data fiddles or Arckaranga shale oil potential down under.

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    • #
      LightningCamel

      Hi Rudd,

      every such tractor trailor loses 48/53 of cargo capacity.

      I think you mean loses 5/53 of cargo capacity (53-48) bit still your point remains valid, if you have to trade length for cargo capacity to add aero then it is more efficient to ditch the aero and use the length for cargo. Besides, as Bernd pointed out, Kamm many years ago provided alternatives to the extended boat tail but for all the reasons already advanced aero improvements are minor in the scheme of things.

      I was interested in your comment about long haul trucks generally doing less than 500k miles. I drive for a moderate sized (50+ B doubles) firm (in Aus) and these vehicles regularly do 1.4M km (900k miles) long haul highway work and often much more in an application where high reliability is required. Just for interest, what part of the world does the 500k figure come from?

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    panzerJ

    They would get even better fuel economy by routing the exhaust gas from turbo-charged engines at the base of the boat-tail(base bleed),but this would cause all manner of plumbing problems plus govt regs require trucks to vent their exhaust gas upwards.

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    Unmentionablenameless

    “Honey, does this make my bum look big?”

    Look at the way gliders are shaped, designed to have the least possible drag, a long slender laminar-flow teardrop shape, and they don’t fly much faster than a car most of the time.

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      Roy Hogue

      About 45 MPH best angle of glide airspeed (greatest distance covered per foot of altitude lost), which is slower than a car most of the time.

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        Unmentionablenameless

        Normal built-up area street speed here is 60 km/h, which is 37.2 mph, though most do about 65 km/h, still, it’s less than 45 mph, and there’s a lot more cars on city streets than open roads.

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          Roy Hogue

          Residential street speed limit is 25 MPH in California. But in Southern California you’re never very far from a main street with a limit of 40 or 45, which means 50 or maybe more to most drivers. Some streets may be lower, 30 or 35 but that still means 50 or more. The freeways have a limit of 65 but that means anything up to and sometimes above 80 (unless you see a Highway Patrol Cruiser). The only thing that keeps speeds at or below speed limit is congestion so bad you just can’t go any faster.

          Lead-foot is a national disease. I felt safer flying.

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    Roy Hogue

    It looks like sound aerodynamics. But it will make backing up even more fun than it is now with that bustle sticking out behind you. Ouch! ;-)

    I wonder how many buyers would go for it since it appears to be true that a car is some kind of fashion or personality statement for many people.

    Are we really that desperate for fuel savings or have we lost our will to go after and use the resources we have available? Just asking…

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      People don’t seem in general to be interested in fuel savings.

      If they were, they wouldn’t sit in their cars in supermarket carparks for half an hour (and longer) with the engine idling. I suspect that at least some will complain that their disposable, Korean econobox uses just as much petrol as the Kingswood.

      May be best to just walk away. In some cases; better to run.

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        Roy Hogue

        The worst understanding of fuel economy I ever saw was my brother-in-law declaring that he didn’t believe it took any more gas per mile to do 90 than it did to do 65 (the speed limit). I didn’t have the heart to set him straight knowing he was a civil engineer responsible for signing off on the plans for bridges and other structures. What can you do with such a poor understanding of basic physics? I was flabbergasted.

        I’d loaned him my Mazda with a rotary engine and he came home boasting of having gone up a steep freeway grade at 90, which he couldn’t do in his car. His wife mentioned the fuel economy and I just stood there with probably a stunned look on my face at his answer. You could drive those so as to get at least 24 MPG all the way down to as little as 6 — it’s all in the weight of your foot. And they were invincible up a steep grade.

        However, the fuel used idling (even half an hour) is such a trivial percentage of what it takes to move the car at any useful speed that I don’t worry about it. Otherwise I would have to side with the Prius owners who put the rest of us down for driving something that runs the engine while stopped at a red light. On many drives I probably spend nearly half an hour at red lights.

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    Rob

    Interesting, Jo
    I once looked into patenting that very idea.

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    Ceetee

    A car with a butt distended like that of an ostrich. How would Lamborghini deal with this design challenge?.

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      Lambo’s usually have a Kamm tail. That’s where there’s a fairly gentle slope (about 12 degrees; no enough to cause boundary layer separation) that’s suddenly truncated; sometimes at an acute angle.

      The pressure drag on the smaller (truncated) tail area isn’t much worse than carrying the slope to a teardrop point; but the vehicle is shorter and lighter. You can’t replace lightness.

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      • #

        Perhaps one of the more famous vehicles with that Kamm inspired rear end were those fabulous 40 inch Fords, which won Le Mans four years running from 1966 to 69, and probably the longest tail of all was on the MarkIV, developed from the J Car.

        That MarkIV which won the 67 Le Mans is the only time in the race’s history that an American team driving an American Car with American drivers Dan Gurney and AJ Foyt won the 24 hours of Le Mans. The two drivers were the fiercest if rivals and pairing them up was a risk, but they won relatively easily, by 4 laps.

        It was also the very first time that the top was snapped off the Magnum of Moet when Dan Gurney, in a moment of pure joy shook the bottle and proceeded to spray everyone around him, something that has now become a tradition in most forms of racing which present Champagne to the winners.

        Tony.

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    Ragnaar

    Looks like the skirts and the boat tail can be had for $3000 but let’s say $5000 with installation. Savings are claimed to be 10%. Figure 90000 miles a year and before mileage of 9 mpg. That’s 10000 annual gallons of diesel and 1000 saved. Figure $3 a gallon for fuel. $3000 a year. And it gets better. The elegance of it. With a 10% reduction in drag, the engine doesn’t have to work as hard which will extend its life. The drive tires get to push 10% less, saving on wear. The transmission at cruise gets to do 10% less work and will last longer. 10% better mileage means your time between refuelings is 10 greater. All this for $5000.

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    John Knowles

    A more economic solution is to use plasma arc ignition. It can even be applied to diesels which normally have no spark-plug as such. You need tungsten or platinum electrodes (make your own) and a modified ignition circuit but the massive high temp plasma arc permits a more complete burn of the fuel.
    Old Faraday noticed that an arc made a much louder noise in a wet atmosphere and I’ve noticed that lightning can be either loud under dryish conditions or stupendous during rainfall. My guess is that something unusual is going on with the water during its interaction with plasma. I doubt this cataclysmic bang is purely a steam explosion.
    Various reports from mechanics claim between 10 and 30% economy.

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