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Thread: Carbon Neutral Hovercraft

  1. #1
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    Default Carbon Neutral Hovercraft

    A BBC News item yesterday on a hydrogen fuel cell powered motorbike http://news.bbc.co.uk/1/hi/world/europe/4353853.stm set me thinking - whats the best way to achieve a Carbon Neutral Hovercraft in say 10 years time?



    Researching the hydrogen fuel cell quickly ruled that out - the motorbike cell has an output of 1kw (1.3bhp) so nowhere near powerful enough. There is a 10kw (13bhp) big brother that might (just) power a small cruiser but the cell alone weighs in at 70kg. http://www.intelligent-energy.com/im...ds/10kw_system _a4.pdf Plus Hydrogen fuel cells are effectively batteries, they run off hydrogen which is generated in another power plant, be it oil, gas, hydro, wind, nuclear or whatever.

    I seem to remember Nigel Beale researching Hydrogen car engines as part of his day job at Cranfield in the 70's. It was based on modifying conventional engines but that still has the 'hydrogen supply' problem.



    Bio ethanol seems to offer a good way forward. It’s a primary fuel produced from plants like corn, wheat, grass, wood chips etc rather than a 'battery' and can be used by conventional IC engines. http://en.wikipedia.org/wiki/Ethanol_fuel The Model T Ford of 1908 was designed to run on either ethanol or petrol. In fact it looks as if the engines we use today could be run on a 10% ethanol, 90% conventional petrol blend (so called E10) right away without mods http://www.drivingethanol.org/userdo...ginesFactSheet .pdf



    The EU is proposing a 20% reduction in carbon dioxide emissions from cars in 5 years. Morally we ought to try to match this particularly if it also brings performance improvements to our craft. E10 improves the burn of the engine reducing both knock and Greenhouse Gas Emissions -. eg Carbon Monoxide reduced by 30% http://www.drivingethanol.org/userdo...andtheEnvironm ent.pdf



    Maybe over the years we can evolve to an 85% Ethanol blend (E85). Before the 'petrolheads' start complaining raw ethanol is high octane stuff and Indy Cars in the 2007 season will use E100 - (100% Bio Ethanol http://www.drivingethanol.org/userdo...EnginePerforma nce.pdf ). Pure ethanol has a much higher octane rating (116 AKI, 129 RON) than ordinary gasoline (86/87 AKI, 91/92 RON), allowing a higher compression ratio and different spark timing for improved performance. To change a pure-petrol-fueled car into a pure-ethanol-fueled car, larger carburetor jets (about 30-40% larger by area), or fuel injectors are needed. (Methanol requires an even larger increase in area, to roughly 50% larger. The production process for Methanol is apparently not very green)



    The only downside seems to be that Ethanol contains approx 34% less energy per gallon than petrol so a craft running on say E85 will need a larger fuel tank. Earlier craft running on E10 would see little consumption difference (around 3%)



    The problem is that in the UK only a handful of Tesco and Morrison Garages currently stock it and production capacity is limited. Perhaps in the classic hovercraft diy spirit Charlie and Jake should grow a bio fuel in the centre of our two 'home' racecourses, produce it themselves then sell it for diy blending at race meetings. I presume as it's not for a road vehicle it would attract no tax….! Apparently an acre of Miscanthus (elephant grass - http://en.wikipedia.org/wiki/Miscanthus ) can produce 1500 US gallons, about enough for 2 Nationals with every craft using using E100. One UK manufacturer in Gloucestershire is about to sell a small (legal) production plant for farmers to produce Bio Ethanol http://www.greenfuels.co.uk/index.htm



    Even the UK Government thinks it’s a good idea - http://www.defra.gov.uk/farm/crops/i...energy/pdf/Bio fuels-leaflet.pdf

    But not everyone agrees, York Uni http://www-users.york.ac.uk/~drf1/bf...ioethanol.html points out that for every 133 units of energy produced 100 units is used in the production process. However University College London points out that with the right production plant design Bio Ethanol could actually net extract CO2 from the atmosphere. http://www.britishsugar.co.uk/Isolat...94175874-67b5- 4c33-9f38-380233f14049/ContentAssets/Documents/Bioethanol/Pu blications%20and%20Research/Imperial%20College.pdf



    So Bio Ethanol seems to me (with only a poor O Level in Chemistry) a viable way forward for keeping our sport going in a Carbon Neutral World. It means minimal changes to our craft and engines and overall the pros seem to outweigh the cons.



    But most of us use more fuel getting to the meetings than in our craft - any ideas for a Carbon Neutral RV? Does it also mean we should encourage renewable plywood craft held together with fish glue rather than fossil fuel based fibreglass? (sorry Russ couldn't resist it!)



    Fuse lit, over to you all for discussion…



    Keith Oakley




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    Default Re: Carbon Neutral Hovercraft

    Interesting post, Keith, as ever.



    It is also interesting how, in the 30 or 40 years since it became an issue, the buzz words have moved through energy efficiency, conservation, renewables, sustainability, etc and now to carbon emissions, carbon neutrality. The latest and best is the "carbon footprint", which may not be a good scientific measure, but does conjure up images of Victorian chimneys and coal miners at the end of a shift.



    In fact it all boils down to much the same thing. That is not necessarily so, of course, but with the current patterns of energy use a reduction in consumption is a better goal than a switch to a different form of consumption. That was the case in 1973 when the oil shock woke people up, and after all the progress since, it is still the case.



    Unfortunately, our racing rules encourage more rather than less consumption. I wrote at length in the magazine a while back about the obsession with classifying formulas by engine size rather than any other parameter. So I am a little sad to see Comps introducing yet another formula on this basis.



    I have proposed several times, and others have also, the idea of a formula where there is no engine limit but the amount of fuel used in the race is limited. This is in effect setting a limit on the carbon emissions of the craft. It would be a very good first step to reducing the carbon footprint of hovercraft racing. Instead though, we get the hugely imaginative F1X.



    -------



    As for construction, you contrast "renewable" plywood with the "fossil fuel" grp. In terms of carbon, they are actually similar - both methods are locking carbon up in the hull. The issues are then what is done with the craft at the end of life and how much energy was used in the production.



    -----



    Interesting topic, and I hope this helps.



    Nick


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    Default Re: Carbon Neutral Hovercraft

    We're doing some research at the university on 'green racing' and the use of bio fuels in race cars, the research is focused on both performance capabilities and emissions



    the good news is once the engine has been tweaked to run the fuel the 85% BioEthanol fuels seem to perform well compared with regular petrol, but the downside is that the Bio fuels aren't as eco-friendly as some would make out, still a step in the right direction is at least a step



    think we need an article in the mag about this



    Tony












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    Default Re: Carbon Neutral Hovercraft

    Schemes for re-cycling of composite materials are being worked on see this link www.ecrc-greenlabel.org



    Regards

    Derek


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    Default Re: Carbon Neutral Hovercraft

    I don't know if I was half asleep this morning, but I'm sure I heard something about carrot reinforced plastic having been discovere by a Scottish uni. If the other rado 2 listener heard it, please confirm I wasn't dreaming...



    Of course, it could have been parrots....


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    Default Re: Carbon Neutral Hovercraft

    We can reduce our "carbon footprint" fairly easily in the case of most cruising craft, if we shift our focus in design from race-derived pedigree to efficiency.



    As an example - we can probably achieve a 20% reduction in carbon emission (fuel consumption) by making our lift systems more efficient. Lift systems which are fixed to the thrust engine speed (integrated and shaft drive) consume around 30% of power; yet under most circumstances 10-15% of power would provide an adequate cushion, with the peak required occasionally. Thus some type of variable transmission could get us to the 20% target. As another eaxmple, we can reduce our carbon emmision by 40% by moving away from 2 strokes.



    Making the point a little wider, most craft development is currently driven by racing. This ethos leads to low efficiencies and high noise levels, and by modifying the design criteria for cruising craft there are some fairly easy gains to be made. Cruising craft and racing craft should be quite different - think F1 and MPV!



    Ian

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    Default Re: Carbon Neutral Hovercraft

    Interesting links, Keith.



    I'm still not convinced on the emphasis that is placed on car emmisions. As Nick says, reducing consumption is the key. To do that would require major social and economic change - moving people closer to workplaces would be a good start. Reducing consumption would also be a good thing at race meetings (no more two strokes?).



    As to hovercraft, the answer is simple (!) - maybe it's time we moved onto vegetable oil burning diesel engines. More efficient, cleaner and cheaper!



    The good thing about cruising hovercraft is that we are re-cycling old car engines - thus reducing their overall carbon footprint. It is said that the emmisions produced during the manufacture of a car are greater than those generated during it's lifetime.



    I'm not sure of the argument for plywood versus resin. By using resin you are producing a product that will outlive plywood by at least three times. Does the carbon emmited to produce (and dispose of) three plywood hulls equal one resin/glass hull?


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    Default Re: Carbon Neutral Hovercraft

    what if the craft has carbon fibre in it lol!

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