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Cory Little’s air-powered bike is turning heads (and pedals)

Posted by on March 2nd, 2016 at 1:02 pm

Cory Little and his pneumatic bike as seen on Hawthorne Boulevard last week.
(Photo: Ted Timmons)

If Cory Little has his way the power source of the future will be compressed air. And to prove it he’s developed an air-powered bicycle.

Little’s prototype has been spotted by several of our readers in the past few weeks. While he lives about an hour west of Portland, he likes to ride the bike around downtown and Hawthorne Boulevard to spread the word and get feedback. He’s spent years thinking up the concept and has been working on it in earnest for about a year now. “This is something I’ve been trying to do for a few years, but decided with the recent oil spills it was time to get busy,” Little said while tinkering in his garage in a YouTube video. That video, by the way, has been viewed over 24,000 times.

Little calls his engine the “Little Engine,” which we assume is reference to his name but also works as a nod to the famous children’s book, “The little engine that could.” (And if you watch the video the engine sounds like an old steam train.)

After many sketches Little built his first proof-of-concept last year. The engine itself (fabricated by Josh Powell) is relatively simple and low cost. It’s a rotary valve that turns two double-acting pistons. The air is stored in a large tank connected to the engine via plastic hoses.

(Photo: Ted Timmons)


(Photo: John Beaston)

Little gives one of these patches to everyone who contributes to his GoFundMe campaign.
(Photo: Ted Timmons)

More than just a product developer, Little is trying to change the world and hopes his invention will wean the world off more toxic power sources. “My engine does not need toxic batteries or fossil fuel, and it is more cost effective than any other motor in that category,” he shared with us via email this morning. In a YouTube comment last year he told a viewer, “I am trying to save the world from being mined out for batteries. I regret to inform you that there is not enough material available to convert our transportation infrastructure over to battery powered. I could go all day on the benefits of compressed air over toxic batteries.”

When not out testing the bike and showing it to curious onlookers, Little is working on building an exchangeable high-pressure tank and designing a pneumatic clutch that will allow for “regenerative braking abilities.” Initial versions of the system used only a 130 psi tank which limits the engines power. Little is currently working on a system with a 4500 psi tank. He also says the next version of the engine will have a lighter, carbon fiber air tank that’s more integrated into the bike’s saddle.

If you’re interested in Little’s project, he’ll gladly share the design with you. He wants to inspire other people to build air-powered machines and everything he’s doing is open-source. You can learn more and contact Little through his website, Facebook page, or GoFundMe campaign page.

— Jonathan Maus, (503) 706-8804 –

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  • Anne Hawley
    Anne Hawley March 2, 2016 at 1:10 pm

    Awesome! I have zero engineering background to allow me to comment intelligently on the design or its limitations, but I’m so impressed with Little’s vision.

    This article is an antidote to all the stressful political news today.

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  • Anne Hawley
    Anne Hawley March 2, 2016 at 1:13 pm

    PS Engineering people: doesn’t it still require some external source of power to compress more air into the tank? Just curious.

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    • 9watts March 2, 2016 at 1:15 pm

      That was my first impression as well, but I think what is going on here is that he’s pedaling (on flats, downhill?) to compress the air in the tank, and then drawing the stored energy back out again (on a hill?).

      If that is in fact what is going on it is very ingenious, though I think I’ll stick with my storage-less propulsion system for now.

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      • Anne Hawley
        Anne Hawley March 2, 2016 at 1:24 pm

        Me too, but as my propulsion system gets less efficient over time, some additional energy storage will be welcome. Nice to think it might be air in a tank rather than lithium.

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      • Pete March 2, 2016 at 9:09 pm

        From what I understand, air is actually pretty heavy to store, but my storage-less propulsion system is up to 185 lbs, and I doubt that’s just the hot air I’m told I’m full of.

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    • Justin Carinci March 2, 2016 at 1:35 pm

      It does. Electricity, generally. Compressed air doesn’t do as good a job as batteries in storing electricity, and it’s super heavy. There have been attempts to make compressed-air cars, but I don’t think they’ve had much success.
      If he’s storing energy produced by pedaling for use later, that’s a different story, but I didn’t see that happening here.

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      • Ted Timmons (Contributor) March 2, 2016 at 4:11 pm

        He’s filling the tank with “shop air” (compressor). He hopes to have regenerative in the next version- this is just a proof-of-concept that doesn’t go far.

        Storing energy has always been the achilles heel of green energy (wind, solar). This is certainly an alternative to batteries. I don’t claim to have any idea of the theoretical efficiency, but hey, it’s a thing.

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    • Tyler March 2, 2016 at 8:55 pm

      That’s right. Enough of all the silly political stuff.

      Bernie says: No, it’s free air – we’re providing it for free!
      Hillary says: I don’t have internet in my cell, but Monica can blow some air into the tank for free!

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    • fozman March 4, 2016 at 11:50 am

      It absolutely requires power to compress the air, however I think his main focus is getting us away from battery technology. A compressed air tank is much more environmentally friendly than a big battery. I would like to hear more about how much power it takes to fill the tank, and what the range is.

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  • Tim March 2, 2016 at 1:25 pm

    Engineering type here.

    Sounds like a fun project, but compressed air is an inefficient way to store energy. Next time you pump up a bike tire, hold the pump. That heat (and the warm feeling you get from the exertion) is lost energy. Pneumatic motors are also notoriously inefficient and typically load.

    In the search for energy conservation, thermodynamics is a required course.

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    • 9watts March 2, 2016 at 1:35 pm

      Efficiency is (often) overrated. It masks so many other dimensions of the problem that can have bearing on whether it makes sense or not.

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      • Chris I March 2, 2016 at 2:22 pm

        Considering that this air-assisted vehicle will require electricity to compress the air into the tank, I think efficiency is a really important factor. This is going to have a larger carbon footprint than a battery-powered e-assist bike.

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        • Eric Leifsdad March 2, 2016 at 2:36 pm

          Gasoline engines are around 30% efficient at best, at 4500rpm. That’s why the heater works so well.

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        • 9watts March 2, 2016 at 2:47 pm

          “Considering that this air-assisted vehicle will require electricity to compress the air into the tank, I think efficiency is a really important factor.”

          Well, for one, air can be compressed with all sorts of things that are not powered by electricity. So I’m going to disagree right off.
          Bicycle pumps were already mentioned. But bikes/pedal-motion could also be used.

          “This is going to have a larger carbon footprint than a battery-powered e-assist bike.”

          Proponents of e-assist bikes like to crow about how the carbon footprint is equal to or even less than a burrito-powered bike. I don’t know enough about the assumptions that go into that claim, but on its face being worse than either of these isn’t in and of itself much of an indictment. We need some numbers before we go too much further with this.

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          • 9watts March 2, 2016 at 3:01 pm

            As for using pedal power to do all sorts of work, including a brief discussion of compressing air, Rodale Press put out a book on the subject 39 years ago –

            Pedal Power: In Work, Leisure and Transportation

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      • Tim March 3, 2016 at 11:38 am

        The bicycle is the most efficient vehicle ever (energy/mass-distance), so I guess the bicycle is overrated and we should go back to horses.

        If you want a fun interesting project, go compressed air. If you want something more practical, go modern battery and electric motor. If you want efficient, stay on your bike.

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        • 9watts March 3, 2016 at 1:03 pm

          “The bicycle is the most efficient vehicle ever (energy/mass-distance), so I guess the bicycle is overrated and we should go back to horses.”

          You missed my point entirely.
          The bicycle has a lot going for it besides efficiency. I didn’t say anything against bicycles or for horses. My point was that if efficiency is your yardstick you are going to miss a lot and the chances of ending up somewhere unhelpful is pretty high. Cory’s point about batteries is correct, even if his use-electricity-to-compress-air-which-I-will-then-carry-around-with-me-in-a-tank-on-my-bike is probably not so smart.

          “If you want a fun interesting project, go compressed air. If you want something more practical, go modern battery and electric motor.”

          I don’t think anyone id going to disagree that electricity and batteries offer lots when it comes to practicality. But Cory (and many others) are operating on the assumption that we need to do more than just choose whatever is the most practical from the available options.

          “If you want efficient, stay on your bike.”

          Again, why is efficiency the metric here? The fact that my bike is
          * cheap
          * easily moved, stored, fixed
          * will probably last a lifetime with only very minor inputs
          * doesn’t require any external fuel
          * or government subsidies
          * is always ready to go

          are some of the reasons I like it. Efficiency only goes so far, tells you so much, and sometimes it is downright misleading.

          “Efficiency is always a contestable concept. Everyone supports the general idea of getting the most out of something. But to go beyond the vague slogans and apply the concept to a concrete policy choice requires making assumptions about who and what counts as important. There are no correct answers to these questions. The answers built into analyses of efficiency are nothing more than political claims. By offering different assumptions, sides in a conflict can portray their preferred outcomes as being most efficient.”

          (Deborah Stone, Policy Paradox and Political Reason 1988:53).

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    • Jon March 2, 2016 at 1:52 pm

      As another engineer type (mechanical engineer working at a company that develops products that use compressed air) I have to agree with Tim. Each time to convert from one energy type to another you lose energy. In this case coal is burned in Boardman Oregon to create electricity. About 1/3 of the energy in the coal ends up as electrical energy. The electricity is sent to the grid in Portland. Due to loses in the electrical system another 6% of the energy is wasted. An electric compressor might only convert 20% of the electrical energy into air pressure that would be used to fill the pressure tank. The air motor is probably less than 20% efficient turning the compressed air into power to turn the wheels. This is an extremely inefficient way to move a vehicle. From an environmental standpoint an electric motorcycle would be much more efficient way to move a vehicle since an electric motor can easily be 80% efficient in turning electricity to movement.

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      • 9watts March 2, 2016 at 1:55 pm

        That is a bit lopsided, since you only tallied the losses for the electricity for Cory’s setup but not for the hypothetical electric motorcycle.
        I agree with you that using electricity to compress air to haul a tank around on the back of your bike doesn’t make much sense, but I’m still not convinced that is what is going on here, or is it?

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        • Gary B March 2, 2016 at 2:20 pm

          Well since he’s working on a 4500 psi version, that’s almost certainly what’s going on here. I doubt he intends to include a 4500 psi compressor on the bike.

          By the way, I’m fairly confident there are plenty of regulations that wouldn’t allow a 4500 psi air tank to be unprotected on a public road.

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          • brian March 2, 2016 at 2:44 pm

            Not too mention the threat of having one so close to your posterior!

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          • Ted Timmons (Contributor) March 2, 2016 at 4:13 pm

            people drive around with scuba tanks on a regular basis.

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            • Gary B March 2, 2016 at 5:38 pm

              Good point. Upon looking into it a bit, OSHA regs require vertical, secured transport with safety caps in place, but those only apply for construction work. DOT regs do apply to transport of compressed gases, but apparently only transporting for commerce (or over 1000 lbs of tanks).

              That said, you’ve likely seen what a 2500 psi SCUBA tank does when the valve gets knocked off. I would like not to be in the same zip code as the 4500 psi tank when Mr. Little gets rear-ended by a distracted driver.

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              • Tyler March 2, 2016 at 8:23 pm

                That rocket-powered bicycle video will go viral real fast. 🙂

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        • Jon March 2, 2016 at 4:02 pm

          There is energy loss in every conversion from one type to another. For an internal combustion engine we take gasoline and turn it into rotary motion at the wheels of a car. To make gasoline oil is pumped out of the ground, then energy is used to convert that crude oil into gasoline. The motor in a car takes the gasoline and coverts it to motion. Only about 15-21% of the raw energy in the gasoline is turned in to motion of the vehicle. The rest is lost with waste heat, friction, etc.
          For an electric vehicle generally we turn fossil fuels like natural gas, coal, and oil into electricity then use that electricity to charge batteries. The batteries run an electric motor that moves the vehicle. Electric vehicles turn about 59-62% of the electric grid power into movement at the wheels. This includes charging, battery, and motor losses.
          A standard home compressor only turns about 20% of the electricity into compressed air and a basic compressed air motor only turns about 20% of the air pressure to turn the wheels for a total of around 4% efficiency for turning grid electricity into movement at the wheels.
          Air motors have very high power output at a low weight so they are used where the tool needs to be light but have high output. Think impact wrenches, jackhammers and similar tools. Efficiency is not their strongpoint. The tools are light weight and ergonomic but are tethered to extremely large compressors with an air hose.
          For transportation the human powered bike is currently impossible to beat. After that electric motorcycles are probably best for low speed transport.

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          • 9watts March 2, 2016 at 4:22 pm

            Your conversions are right on, but it is important to keep track of all the losses system-wide if we trying to compare apples to apples.

            “Electric vehicles turn about 59-62% of the electric grid power into movement at the wheels.”

            But the electric grid power, typically, has already lost anywhere from 30-70% of the energy contained in the fuel that was shoveled or piped into the power plant to heat. 0.45 x 0.60 = 0.27


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            • soren March 2, 2016 at 5:23 pm

              it’s almost as if renewables do not exist in your world.

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              • 9watts March 2, 2016 at 5:29 pm

                It is almost as if constraints, biophysical limits, do not exist in your world.

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            • Jon March 2, 2016 at 6:37 pm

              When you factor in thermo-fossil fuel inefficiencies in to the system electric vehicles are not much better than gasoline vehicles. Coal plants are 33-40% efficient, modern combined cycle natural gas are approaching 60% fuel efficiency. Sadly compressing air and using it to drive a vehicle makes gasoline and electric vehicles look extremely efficient.

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              • 9watts March 2, 2016 at 6:47 pm

                “Sadly compressing air and using it to drive a vehicle makes gasoline and electric vehicles look extremely efficient.”

                And bicycles—the burrito-powered kind—make all three look extremely inefficient.

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              • soren March 2, 2016 at 7:27 pm

                who said anything about fossil fuels?
                i charge my ev with wind. and according to a life cycle analysis from the union of concerned scientist it gets well over a thousand mpge (including the cost of vehicle manufacture [mine was used], power plant construction/maintenance, and transmission line construction/maintenance).

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              • 9watts March 2, 2016 at 7:37 pm

                “i charge my ev with wind.”

                And your wind is charged with fossil fuels, all the way back to the mines. Cement, steel, aluminum, copper, all the ingredients in your car and the turbines, and wires, and batteries are not carbon free.

                While the same burdens scan, in principle, be hung around the neck of a bicycle, the life cycle material and energy picture is infinitesimal when compared with your EV.

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      • Ted Timmons (Contributor) March 2, 2016 at 4:20 pm

        Jon, the coal argument is spurious. It’s going away, and those of us willing to pay an .8 cents per KWH are supporting green sources- in fact, 98% of it is wind.

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        • 9watts March 2, 2016 at 4:28 pm

          “Jon, the coal argument is spurious.”


          What is spurious is your dismissal of coal. I’d like it to ‘go away’ too but that is not exactly what we are seeing. And if you think that substituting natural gas or oil for coal is going to buy us anything (time, indulgences) or interfere with the rising sea levels, you might want to think again. We can’t afford to burn any of it, but right here right now if you are using electricity almost all of it is generated with fossil fuels, even right here in supposedly hydro-rich Oregon:

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          • Ted Timmons (Contributor) March 2, 2016 at 4:31 pm

            We can vote with our dollars and get purely green energy. It’s an affordable cost (a few dollars/month). It even excludes large hydro.

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            • 9watts March 2, 2016 at 4:36 pm

              If it were only that easy….

              What you and I see on our electricity bill is all very reassuring. Go green! But this household level switch doesn’t scale at all. To do what you are implying (and many suggest is feasible) takes an unprecedented, inconceivable, effort, not just financially buy materially and energetically. For more see:

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              • soren March 2, 2016 at 5:41 pm

                Your perennial skepticism aside, a switch to renewables is inevitable:



                And the infrastructure required to switch to renewables for most of our generation is modest:


                In fact a recent study suggested that we could switch the majority of our generation to renewables using existing technology:


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              • 9watts March 2, 2016 at 6:01 pm

                “a switch to renewables is inevitable”

                I guess we’ll find out.

                Everyone I know wants to believe this, wants to think that the smart people in those tall buildings will figure this out for us – including the smart people in the tall buildings. But just because everyone wants to believe this, and makes noises that are congruent with that desire, doesn’t ipso facto mean it will come to pass (in time). There are real constraints, real obstacles to a wholesale 1-for-1 switch to renewables. And I am not talking primarily about load balancing or transmission, both of which present obstacles, but about the magnitude of the materials and energy (all of it 100% dependent on fossil fuels) required to roll this out. Even the studies you cite stop at 80% by 2050 (34 years out). And you know that NREL is going to round up given what their role is in this game.

                David Brower and later Amory Lovins referred to this approach as Strength Through Exhaustion.

                There is a much easier, cheaper, faster way—an end run around this whole thing—and riding a bicycle is the perfect instantiation of this alternative approach.

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              • Tyler March 2, 2016 at 8:37 pm

                YOU can go renewable right now in some climates, but not all unless you have big $$. One house at a time. Install super efficient appliances/lights. Start with a super insulated, passively heated home requiring little heat other than the sun and include some heat storage for cloudy spells, install a solar electric system with batteries for night time, add a windmill if you want another source of electricity, etc. Use solar heated water. Harvest water. Any one home can do it today. It will cost some money that most will not be willing to spend, but it can be done for A HOME. The fewer electric appliances you can live with the less $$ you have to spend.

                BUT for “the grid” to go 100% renewable is another story and that will not happen unless there are HUGE breakthroughs in storage technology and we aren’t even close yet.

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              • soren March 3, 2016 at 1:17 pm

                BUT for “the grid” to go 100% renewable is another story and that will not happen unless there are HUGE breakthroughs in storage technology and we aren’t even close yet.

                The revolution has already occurred:


                Current transmission technology is already sufficient and relatively inexpensive:


                the idea that a switch to renewables is too expensive is primarily propaganda that originates from the fossil fuel industry (and conservative billionaires like buffet and the kochs). the cost of renewables has plummeted so much that most new capacity being added in the USA is powered by renewables. moreover, just about every credible study suggests that we could switch most of our power generation to renewables now. imo, the only thing missing is political and societal will. interestingly, this resistance to renewables is largely unique to the USA. a local case in point was the recent implementation of a carbon tax in BC by the conservative “liberal”* party. the tax has been a wild success and the enormous “costs” that skeptics complained about never materialized.

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              • Tyler March 3, 2016 at 8:48 pm


                I looked at your article:


                It’s mostly wishful thinking citing a few stats, little or no engineering data. So, no, the revolution has not already occurred. And the articles conclusion that the “intermittency” problem is essentially solved is total BS. I applaud the efforts of those working on the problem and hope they eventually succeed, but the methods mentioned in the article will provide only marginal improvement over what we have today. The storage problem is insurmountable with todays technology and budgetary restraints.

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        • Adam H.
          Adam H. March 2, 2016 at 4:32 pm

          Oregon gets 50% of our energy from hydroelectric. Coal makes up a very small percentage, at 6%.

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          • 9watts March 2, 2016 at 4:50 pm

            A familiar myth.
            Notice the category: Net Electricity Generation… we don’t have any coal within our borders, but that doesn’t mean it isn’t burned to generate the electricity we consume. For the state as a whole we burn roughly as much coal as we send water through turbines:

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            • Ted Timmons (Contributor) March 2, 2016 at 4:53 pm

              I’m more than happy to try to make things better. Bicycling and busing, as an individual, doesn’t change anything either. But it’s tiny steps that hopefully add up. If more consumers go on the green source plan from PGE, great.

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              • 9watts March 2, 2016 at 5:16 pm

                But you’re missing crucial distinctions between how these three things scale: (a) bicycling, (b) buses, (c) green power.
                To scale bicycling by three orders of magnitude (from 100 to to 100,000 daily riders across the Hawthorne Bridge, say) doesn’t face any material or financial barriers that I know of. People who don’t now ride, many of them, already have bikes in their garages. They may not know how to ride them in traffic, but they could learn, and it would take only some will power, and a few simple tools.

                To scale bus-use by three orders of magnitude (e.g., from 10 buses to 10,000 buses), on the other hand, would take a significant investment in terms of rolling stock, drivers, pension plans, etc. Conceivable but very expensive, and it would almost certainly take several decades of very concerted effort.

                To scale renewables by three orders of magnitude (from 1GW to 1TW) not only requires investment in the solar panels and wind turbines to produce those kWh, but also in transmission infrastructure. The materials and energy required for each and every piece of this infrastructure are currently (and for the foreseeable future) mined, refined, transported, processed, etc. using fossil fuels at every step. When we increase our investment of renewables exponentially, at the rates we now are, the amount of fossil fuels this investment corresponds to is considerably greater (in year 1, 2, 3, 4, etc.) than the theoretical offset the electricity generated by those panels and turbines might contribute (in year 1, 2, 3, 4, etc.). As long as the *rate* at which we install renewable capacity is exponential it will take a rather long time to get ahead, catch up, actually reduce, never mind eliminate, the fossil fuels that we thought our purchase of green power signified. The link I included above explains this in much greater detail.

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              • Ted Timmons (Contributor) March 2, 2016 at 5:18 pm

                Sure. And if we do nothing, it doesn’t improve. I’d rather be on the side of change than the “oh well, we have Boardman, can’t do anything about it” side.

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              • 9watts March 2, 2016 at 5:26 pm

                I never said anything about doing nothing.
                I was merely responding to foolish talk about things that are not possible. I want us to proceed with our eyes open, not chase after promises those who glibly repeat them are unable to keep.

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              • soren March 2, 2016 at 5:51 pm

                the agricultural energy used to pedal a bicycle depends on fossil fuels and not necessarily less efficient (90-120 mpge for the standard american diet) than an e-bike or even ev. we need to decarbonize both energy generation and agriculture.

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              • soren March 2, 2016 at 7:35 pm

                kifer’s do not properly account for the co2e of food. moreover, assuming that someone biking 1000 miles will eat 22 lbs of rice is laughable.

                two evidence-based estimates:



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              • 9watts March 2, 2016 at 7:54 pm

                “Yes, we do count the calories used by the driver (which are insignificant)”

                That struck me as bull$h!t. What are the authors of the first piece you linked to assuming about the heart rate of the cyclist if they feel qualified to dismiss the driver’s metabolic rate as insignificant?

                Avg driver’s diet + 20mpg car = 20mpg
                Avg walker’s diet + no car = 30mpg


                Your second source, though much more nuanced and interesting to read, also appears to forget to burden the driver’s half of the calculation with the diet of the driver (and/or passengers). Why is the food the driver eats left out?

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            • Adam H.
              Adam H. March 2, 2016 at 4:56 pm

              Huh, interesting. Where is the electricity generated? Do these numbers represent literal electrons sent over our borders or as factored into the goods and services we import?

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              • 9watts March 2, 2016 at 5:04 pm

                The electricity is generated all over the place. The pie charts I linked to don’t show anything related to goods and services, just kWh consumed within our borders (and generated by the utilities from whom we buy kWh).

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          • Pete March 2, 2016 at 9:23 pm

            Do you have sources? When I last looked this was far from true. My electricity in the Gorge came primarily from the Boardman plant, despite being located squarely in between dams generating electricity being transmitted all the way to California. When I moved to California, one reason I chose to locate in Santa Clara was Silicon Valley Power’s prices and renewable options. I use far more ‘green’ energy here in California than I could use anywhere I lived in Oregon when I lived there, but I’d be interested to know if that’s changed.

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          • Pete March 2, 2016 at 9:35 pm

            Here’s a more accurate look at power distribution:

            Note that we use Pacific Power in the Gorge; in Portland you have better choices from PGE.

            Also things will change in the coming years as PGE brings its combined-cycle gas plant online which should eventually result in decommissioning the coal plant. PGE’s hydro contracts are set to expire this year, if I’m not mistaken, and currently NG is the most cost-effective electricity source for the foreseeable future.

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      • Mike Reams March 3, 2016 at 1:49 pm

        One problem I see is that highly compressed air is a totally different thing than the kind of pressures you see in a bike tire (120 psi vs 1000+ psi).

        Do an amazon search for Benjamin High Pressure Hand Pump. These pumps are for PCP Air Rifles.

        The problem is that at these high pressures, you need several stages and specialized gaskets in the pump. The kind of pressures involved generate a lot of heat that can degrade the parts. So, you have to go very slowly.

        The alternative is to stop by AirGas or, something like that on your way to and from work. The air pump at an ordinary gas station will definitely not fill a high pressure tank.

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    • Brendan Treacy March 2, 2016 at 1:53 pm

      It’s a really interesting idea. I don’t think it’s a system that can recharge the air tank because that would require pedaling backwards. Also kind of sketchy how he puts his feet on pegs and the pedals just spin around. Seems like there’s a more elegant way to pull that off. Even if compressed air isn’t all that efficient it may be better in the long term that batteries or fuel cells just because it’s cheaper and there’s no limiting rare materials. Maybe some other hydraulic medium would work better than air but still not be too heavy? Cheap, light and simple are the hallmarks of successful bike designs.

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      • Brendan Treacy March 2, 2016 at 2:05 pm

        Also..why not just us a rotary air tool to go from pressurized air to rotary torque? That would eliminate the pistons and all but one hose. A 90 deg angle grinder is $15 at harbor freight. If you attached that to a small crank on a freewheel up above the main crank, you could rid of the spinning pedal problem too.

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        • colton March 2, 2016 at 2:30 pm

          Naw, just crack open a nozzle off the back of the tank and zoom off like a popped balloon!

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        • Ben Fleskes March 3, 2016 at 6:07 am

          Rotary air tools provide excellent high speed (think 20,000 – 40,000 rpm), but low torque. To get sufficient torque to drive a bicycle it would be necessary to add some additional gearing, which would then make it inefficient.

          Cory Little has cleverly decided to use linear air cylinders with offset cranks to get the necessary torque.

          As a first generation ‘proof of concept’ developed with minimal resources it’s well done. Some of the best funded engineering labs would be hard pressed to do equally well with 10x the resources.

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  • Adam H.
    Adam H. March 2, 2016 at 1:53 pm

    Cool concept! Personally, I prefer my bicycles to be burrito-powered, but to each their own. 😉

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  • Brian E March 2, 2016 at 2:16 pm

    Awesome. One person with a vision, takes initiative, makes it happen and rides away the steam punk genius.

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  • Chris I March 2, 2016 at 2:21 pm

    There is no freaking way I will ride a vehicle with a 4500psi tank of compressed air strapped to it. This man is a mad scientist.

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  • colton March 2, 2016 at 2:24 pm

    I’d be more excited to avoid the rain than to avoid the minimal work required of a bike.

    That said, I would think that anyone interested in such a bike would want to know:

    1) How far will it go between charging it up? and
    2) Should I be concerned about having a virtual bomb encased in carbon fiber sitting under my butt?

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    • Ted Timmons (Contributor) March 2, 2016 at 4:21 pm

      I got the idea that this one only goes 2-3 blocks. It’s just a proof-of-concept. Hence the high-pressure system.

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  • Spenzor March 2, 2016 at 2:32 pm

    Fun idea. Not sure how you stop the tank from becoming a projectile missile during an accident. 130 PSI maybe ok but the hypothetical 4,500 PSI tank… I youtubed a couple videos and am skeptical that I would want one on my bike.

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  • Daniel Costantino March 2, 2016 at 2:35 pm

    That photo was clearly taken on SE Stark in Montavilla, not on Hawthorne. Otherwise, same question everyone has regarding recharing: is it pedal-powered? If not, it’s just pushing the problem upstream.

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    • Ted Timmons (Contributor) March 2, 2016 at 4:22 pm

      Definitely on SE Stark, right in front of Bipartisan. But nothing about “he likes to ride the bike around downtown and Hawthorne Boulevard ” says he doesn’t also ride elsewhere.

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  • Todd Hudson March 2, 2016 at 2:51 pm

    Cool idea, but I sure don’t want a tank of highly compressed air sitting below my nether-regions.

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  • hotrodder March 2, 2016 at 2:53 pm

    The motion of the connecting rods reminds me a little bit of the motion of
    Theo Jansen’s “Strandbeests”

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  • hotrodder March 2, 2016 at 2:54 pm
  • GlowBoy March 2, 2016 at 3:32 pm

    The article is extremely clear: while he’s working on regenerative braking, the air on the prototype is compressed 100% by electricity.

    This might well be extremely inefficient, but I suspect it would still use a fraction of energy to get a human around than even an extremely energy efficient automobile.

    I know this looks like a fail compared to many BPers’ standard of purity, the burrito-powered bike, but it’s probably far cleaner than the cleanest automobile, still being used by a majority of Portlanders.

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  • bikeninja March 2, 2016 at 3:43 pm

    This would be great if they didn’t charge to use the compressed air line at gas stations ( like in the old days).

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    • 9watts March 2, 2016 at 3:46 pm

      you mean cleverly parasitic?
      If we’re interested in alternatives to fossil fuels, stealing compressed air from a filling station is hardly an end run around the problem.

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  • RushHourAlleycat March 2, 2016 at 4:01 pm

    Except that it does not power itself. Not uphil, not on flatlands. It’s somewhat functional for steam punk. But mostly its just a way to solict donations.

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  • The Bike Concierge March 2, 2016 at 5:31 pm

    Cory stopped by my shop with the bike recently. I have to admire his willingness to think outside the box. Having seen the result of compressed gasses gone bad I would be uneasy with the current rendition of his idea, but crazier concepts have matured in to workable ideas. I agree with the concerns over efficiency losses, but it will be interesting to see where this goes.

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  • Tom Hardy March 2, 2016 at 6:15 pm

    Burritos do make a lot of gas, but the exhaust is too inefficient with shorts.

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  • Tyler March 2, 2016 at 8:49 pm

    I’d give Cory an A+ for effort and ingenuity. Good job on this prototype!

    I don’t think there is much of a future for the air-powered bike for the reasons listed by the engineering types above, but this proof of concept bike is pretty cool.

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  • Charles McCarthy March 2, 2016 at 8:56 pm

    I’d like to know the answers to these two questions that seem to me to get to the practicality of the system:

    How long does it take for a common bicycle pump to put 100 lb into the airtank?

    How far will that charge take you?

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  • Cory Little March 2, 2016 at 10:49 pm

    Thank you for all the comments about my project. To address the thermodynamic concerns of compressed air energy, the heat generated during compression can be put to use, just as the endothermic (cooling) reaction of decompression is already being used to offset friction, and cool the motor. The efficiency is also not really the issue, as solar, wind, and wave energy can supply ample power, but require some way to store and release the energy on demand. Since we know the future will rely on inconsistant renewable energy, it is critical to develop compressed air for storage, as electric batteries are toxic, and have limited lifespans. This rotory valve is the first of its kind, and the potential applications for this easy to maintain motor are endless, and not limited to transportation. It drastically changes the cost of creating an air powered machine, making many new enviromentaly friendly devices marketably viable.

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    • Jon March 3, 2016 at 6:31 am

      Efficiency is always an issue with transportation. A human powered bicycle is the most efficient and lowest environmental cost way to get around. A compressed air powered motorized cycle is probably the least efficient and highest cost environmental way to get around. Is building an air compressor a green process? Renewable energy has environmental costs. Wind turbines kill birds by the thousand. Hydro has destroyed the Colombia river’s salmon runs. Solar uses many toxic processes to create the panels. Renewable power is better than fossil fuels for the environment but by far the best thing we can do is use less energy and that means efficiency is critical.

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      • 9watts March 3, 2016 at 7:03 am

        Amen, brother.

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      • GlowBoy March 4, 2016 at 1:49 pm

        “A compressed air powered motorized cycle is probably the least efficient and highest cost environmental way to get around.”


        A fossil fuel powered automobile (or, worse, truck) is the least efficient and highest cost environmental way to get around.

        Of course you could let the perfect be the enemy of the good, and let your purism stand in the way of progress. I’m sure a compressed air e-bike will still get several times the effective fuel economy of the best BEV (around 120 MPGe). Personally, If powered bicycles get people out of cars, I’m all for them.

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    • Mark Milner March 5, 2016 at 11:28 pm

      Dear Cory have you thought of using the frame of the bike or major sections of it, (a slightly oversized down tube or horizontal cross bar etc) as part if not all of the storage area for some the compressed air capacity, thus reducing the size of the primary storage vessel. The sections could be linked together which would reduce or even eliminate some hose connections. Items like the drive pistons could perhaps be engineered into the bottom bracket assembly. You could even close the central area in to form just one tank.

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  • wsbob March 3, 2016 at 2:25 am

    Interesting. The compressor needed to charge the bike’s storage tanks was the second thing that occurred to me, seeing the picture, top of this story. Anyone that’s ever worked within hearing range of a big air compressor, knows what a pain they are to be around. Very ingenious DIY bike is the first thing I thought upon seeing the bike. Seems like Cory has some very good smarts and skills he’ll likely be able to apply to developing other ideas, in addition to this one.

    By the way…yesterday, for the first time ever, I test rode an electric assist bike, and an electric assist scooter. At Pio Sq, an ebike shop from the east side was doing a promo for the ‘genze’ line of bikes they’re selling. They cordoned off about an 80′ square area on the square for test riding the bikes. So, speeds over about 7 mph weren’t practical. Fast enough though, to give a good idea of the bike’s functionality…handling, operation of controls, assist from the motor.

    Both bike and scooter had great acceleration. They wanted to go-go, even with just a slight twist of the scooter’s throttle grip, or a push on the bike’s pedals. I’d love to try them out for a test commute from downtown over the west hills into Beaverton and back, to see how the battery range lasts. Staff said they had a 30 mile range.

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  • Aaron March 3, 2016 at 8:58 am

    Congrats! You invented the motorcycle.

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  • Psyfalcon March 3, 2016 at 9:39 am

    Its not just the efficiency of the compressor.

    Its compressor+ life cycle of the motor vs the life cycle and efficiency of batteries. Continued mining for the elements in batteries is another “not green” thing.

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    • Tyler March 4, 2016 at 8:15 pm

      Being alive is a “not green” thing. Dern it.

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  • KB March 3, 2016 at 10:39 am

    I posted a comment about this on the blog “biking in LA”. A link to that was posted a moment ago but as a URL triggered this sites mandatory moderation/delay so you have to google it yourselves, todays “morning Links”, not hard to find!

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  • Karl Brown March 3, 2016 at 10:42 am

    (as previously published on a blogger who linked to this story today_

    March 3, 2016 at 10:16 am

    Ok, I think some context for what compresssed air as a means of mechanical energy storage is, and is not.

    First those few practicing in it, like the hot babe featured in a two page spread sitting gloriously on her big toy in full color, all rights reserved, not a new pic, in our WSJ print no less edition, not just a blog, barely a week ago, are not all about the hydrogen economy stupid, they done dat, been dear to it, and are all about nitrogen, oxygen, etc, because, duh, it’s everywhere and ‘free.’

    Take COMBINED HEAT AND POWER for example (CHP), in that scheme you burn some coal or whatever, to make obsolete distrubatable energy (hey, if ‘mikey’ want’s it or whatever why not? Well….) and get to keep the heat for free, and just pump the fumes into the sewer line so the kids downhill can deal with it.

    Compressed air goons want to use the wind our weather systems need to stay stable, or capture heat otherwise reflected back into space especially if by PV systems, and heat water with it, because warm water is cheaper to store then metal etc. melting/burning hot air.

    So some clown can go very far with this stuff thinking higher pressure is the way to greater range. Greater volume is duh, not pressure.

    Warm water is free duh, not just air.

    Recenting Washington Elemtary sold school bus 3600 pound composite tanks for, in undestroyed, truth be told, barely used condition, for under two cents each. (though with tax etc. the bidder has to pay over a dollar total, well over.)

    In doing so they denied the children dozens of tanks able to store at very low pressures enough energy to tow very long bicycle trains of peers many miles a day.

    In doing so, in buying new tanks with federal assistance to be used for internal combustion old engines, with fracked fuel, they deny there students grandchildrens a planet. On PBS the arc was shown last night, with the only assasination victim’s brother in law serving a year on it, as there alternate future, well one Noah’s among them if there very very very very very lucky that is. If that is luck.

    IN the movie of course the bed bugs get on the boat, not just the good guys and kids mates.

    In the real world illiteracy about energy is at an all time high.

    For example the energy stored by standing not sitting seems like the opposite is true- that more energy after a while at least, is on board, after plumping down into the bean bag, versus standing.

    We know that is not true, that time on a bike, pedaling, is time in recovery, therapy, the secret of our prowess in and especially out of bed, if we survive the trip that is.

    Last night though we learned the trip up, and back down, is not as dangerous as the year on the station, no kidding.

    We saw that in Kubrick of course, all the crew is not needed by HAL, who can lip read, but does not give a dam.

    So back to sub crystal version of air, not solid, nor liquid, but instead of baked corn husk fiber h20 molecules letting it be more dense, yet heavier by volume. Such heavy air is not presently available for purchase, despite Russian slave built rail shipping fracking distillates as if they are pipelines when they are anything but.

    A great secret is that the methane stored and wasted in the ground killing neighbors did so tax free. Because it was never sold. On our coasts billions (not adjusted for inflation!) where spent to heat that shit up for our domestic pipelines, all wasted, and since additional billions has been wasted to condense our better left in the ground dinasoar farts, for the machines to do that with ancient dirty dumb means.

    The energy is free to a fracker. Poor countries burn half the energy found by our CIA whose purpose is only to liberate them of it, before selling the worst of it, in demonstration fires above the sea, like fireworks in reverse. Nobody pays. No carbon tax for testing a well and wasting a trillion dollars of gas to prove a billion bucks of oil can be loaded after a trillion dolllars of damage is done leaking some of it and that too light and voluminous to sell junk or so said every still even punk.

    ANd helen goes on youtube in pixeled might as well be square shape saying it is about Bush’s staying hard for shaved surfer chicks or whatever and we are commies to have any fission at all, liquid helium ain’t no answer, not that she needs one, her dirty jokes are funny enough.

    So low pressure energy storage like where that gas was? Nobody dares speak of it.

    Low pressure. No thermal mitigation. Come on people! EFFICIENCY IS A SCAM. Literally everybody knows that.

    Lighting is diminimus. Transportation- all of it. Not just airline travel.

    It is about taxing, redistributing wealth, hogging land, nothing else.

    We can do that cleanly or with the best and brightest among us recognising us as the only threat, and taking us down with a few engineered molecules if not germs.

    Or we can consider the simple and few facts that matter.

    The tubes do not need to be super low pressure or at negative pressure duh. This is not complicated. Cargo people high not needed in right of way.

    Liquid forms of energy like nitrogen are not just for seducing the freshman with tasty ice scream made instantly on the fly.

    Phase change is important.

    Literacy, like it once was, all important.

    Except it is no longer like it was in texas for my first lover about having the best handwriting in the state as a kid.

    Kids having mastered carnal knowledge puberty for decades can and should move on to mechanical energy concepts and beyond. By beyond I do not mean microwave ovens lol or how to make plutonium from tapping into high tension powerlines.

    Or power cars with liquid aluminum, none of that nonsense please.

    Saltwater etc. all misses the point.

    Rocket science is easy if you have a transistor and a clue.

    Helium can indeed distribute fission energy without becoming radioactive itself, it does not gain any weight regardless of how ‘hot’ it gets.

    So Toyota places it’s bets on the greatest trojan horse ever built- a hydrogen tank equipped prototype in quasi production that with it’s standard tanks can go farther then any SUV fully filled with premium gas can using just air and an engine that might as well be free compared to the full production costing of fuel cells.

    Half the energy is wasted as currently operated. HALF! Versus much less if free gas is put in the same tanks, at even lower pressure for daily use, higher if you need to get to the beach on the other side of the continent or whatever without stopping, a trailer full behind in a wiener tank light and trivial to tow even with pedal power needed or not for that (depends on how much booze or belly fat passenger’s bring)

    Energy is free. Storage is trivial.

    Oil ain’t it, fossilised carbon flamable used to just blight land- flowing freely on surface it was toxic waste, left alone, until idiots realised dumber people could make them rich, and did, destroying our world likely for all time, unless, unless you reading this take simple action. And that isn’t donating petty cash to someone who never even considered college or whatever like that.

    Dropouts like Gates, men of profound Hubris like Z freak, however well intended, strike evil cords loudly, materialistic younger babes and kids behind them, ugly as any ever to reign, over 30, or nearly that, to be trusted by fools, deposed by necessity if only but if necessary with whatever means necessary.

    Smash your windows phone. Used Iphone 5’s are $50 on or less routinely.

    Better models availalbe in months given a market from me or any one able to go on any number of logic websites, Transistor’s are not national security resricted. AI is cheap.

    Lithium irrelevant.

    Teaching us how to build houses in trees next to streams like in disneyland of yesteryear at least that use falling water to do work so we can chill, that is the answer.

    Tidal, thermal, energy is everywhere and lesss then free.

    I spoke to a man who heated his office with coal recently to save hundreds a year over oil. Not kidding. He guess it was from Pen state, did not care, said he was an environmentalist, has installed air conditioning to deal with a window instead of opening it in Near Canada on 80 degree days.

    And so it will go on unless.

    Women and men, children and plants, defend themselves.

    Walk, talk, stalk.


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    • Pete March 3, 2016 at 3:05 pm


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    • not that Mark March 3, 2016 at 5:30 pm

      Regarding Karl Brown’s post:

      Space alien?
      Possibly the best commenter ever?

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  • David Lewis March 3, 2016 at 11:23 am

    There are cranksets that have built-in freewheels, which this conceptual prototype needs for safety. The Metropolis is an affordable example.

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  • Peter March 3, 2016 at 1:12 pm

    I love the concept of an electric/pneumatic bicycle for solving the hill problem–ie, really steep hills that cars have no problem with but a bicycle will have to climb slowly.

    I like the regenerative braking idea, but I would be fine with a switch that converts some/all of my pedaling action into recharging the power supply. So when I use power to go up that hill, I can restore it by pedaling down the other side (e.g., gravity will move me along so I can pedal to compress air into the tank).

    Just a thought…

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  • John Liu
    John Liu March 4, 2016 at 11:50 am

    Impractical to use pedaling power to charge the 4500 psi (300 bar) tank. Unless you plan to pedal at 500 watts for many, many hours while going nowhere.

    Dangerous to have a 4500 psi tank exposed on a bicycle. Accidents, crashes, vandalism, equipment failure, general neglect can all turn that tank into a bomb.

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  • Loretta Walsh October 4, 2017 at 6:10 pm

    A french citizen makes air tanks out of carbon fibre, and has a car for city use. It was on 60 minutes on TV last year.

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