Half a croissant, on a plate, with a sign in front of it saying '50c'
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Air system bike

Bicycle cannot be operated without air.
  (+3, -1)
(+3, -1)
  [vote for,

This bike always has flat tires. The tires are quite large like motorcycle tires, but only a narrow band contacts the road, so they can be visualized teardrop shaped. The tires are inflated at the beginning of each ride in stationary mode. The pedals turn an air pump that inflate the wheels. The air is pumped through the rotating hub into the tire.

Once the tires are fully inflated, and system pressure is over 120psi, air can be released. When air is released it travels through a pneumatic rotory actuator in each tire. This spins the tires in conjunction with inertia and gravity. Air can be directed to spin both, or either one of the tires. Ram air from front dead centre of the vehicle also supplements the supply by maintaining static pressure.

All the while, the rider is pedalling. The rider never stops pedalling and always maintains the same rate whether stopped, travelling down hill, or turning. Air is released by a standard motorcycle throttle, and the drive tires are determined by a three way switch with a fourth position for stationary mode.

rcarty, Jun 19 2012

Tata Motors Air Car http://www.gizmag.c...-air-car-mdi/22447/
[UnaBubba, Jun 22 2012]


       I suspect the number crunchers will be along shortly to shred the assumptions, but I like it.
normzone, Jun 19 2012

FlyingToaster, Jun 19 2012

       Sorta like bagpipes? Nice.   

       I get the part about being driven by the air supply, but what's the benefit to keeping the tires flat?
ytk, Jun 19 2012

       No benefit, the first line is more of a tongue-in-cheek comment. I guess it helps me visualize the bike after all the times I've entered the garage to find flat tires.
rcarty, Jun 19 2012

       Using oversized tires seems like the worst possible way to store energy via compressed air on a bike.   

       The only advantage I see is that if you expect the tires to always be flat when you start, and you just pedal to pump them up, it is in some sense more convenient than occasionally finding your tires flat. Of course if you actually have a leak in your tire, you could go for a long time without noticing except that you will be more and more tired at the end of each trip as the leak gets worse.
scad mientist, Jun 19 2012

       Oh, I see now. The tires are used to store the air. Somehow I missed that part, and figured there would be some sort of air tank. Hmm… I'm not so sure about that part of the idea. Seems like you would want to have a constant pressure in the tires as much as possible, and probably the worst place to store your high pressure reserve air is in the part of the bike that takes the most physical abuse. Still, that all just comes down to minor details.
ytk, Jun 19 2012

       What about balloons?
daseva, Jun 19 2012

       I think the tires should be ordinary, but the frame should be inflatable. Obviously you can't ride it unless the frame has enough air pumped into it to make it rigid....
Vernon, Jun 20 2012

       Ive been thinking of lightness recently. Air power fits into that paradigm. If you strip the frame of a road bike and put in an air pump where the chain would be it's''already a bit heavier. Nylon airlines will do the rest. But then there is the problem of storing air. Why add an extra tank when there are tires? Theres probably a few good reasons why not , but to my mind if the air supply is constantly being replenished ie the tires are constantly being pressurized by pedalling, the tires can constantly operate the motor at reserve pressure.
rcarty, Jun 20 2012

       Given that the bike has a strong tubular frame, it makes more sense to store compressed air in the frame, shirley? It also simplifies the plumbing.
MaxwellBuchanan, Jun 20 2012

       Not also but only?
rcarty, Jun 20 2012

       Mmmm, pedal powered bagpipes with a strong tubular frame and toroidal bag, I like this.
pocmloc, Jun 20 2012

       //Pedal powered bagpipes// Don't shoot! He's getting away!
lurch, Jun 20 2012

       balloons would not give enough backpressure.
RayfordSteele, Jun 20 2012

       Two problems, air pressure only has passable energy density at high pressures and rubber tires are way heavier than Al or FG over Al tanks. Also spherical tanks are the best shape, toroids are going to be really inefficient.
MisterQED, Jun 21 2012

       It's just a terrible idea. The tire changes pressure from normal to harder than a tube of steel to store a tiny volume of energy. The rider wastes 30%+ of their effort making heat. The bike is now equipped with heavy and finely crafted pneumatic equipment. The rider must learn to co-ordinate a hand throttle where they formerly had a brake. A puncture to the tire now represents a fatal threat to the cyclist and bystanders. The weight of the wheel/tire is substantially increased. The bike is now pointlessly capable of 2wd which is likely to cause the rider to loose control on slippery surfaces (think of "drifting" but in a bad way). The rider has no ability to increase output in an emergency, or operates with a fantastic reserve of power maintained at a further blow to efficiency. The need for lubrication and maintenance is increased dramatically. Repairs now require specialized skills and tools not widely available. Many parts must be made to high precision and of specialized expensive materials. The rider experiences no marked improvement in ergonomics or biomechanical efficiency.
WcW, Jun 21 2012

       Scathing critique really in halbakery style? I mean these ideas here are not my most obsessively protected, telling people I'm wanking when I'm really working on them, world secret police agencies are watching my every move, and I'm in a race with a secret competitor to complete, ideas. Those are Vernon ideas.
rcarty, Jun 21 2012

       //It's just a terrible idea... need for lubrication and maintenance is increased dramatically...Repairs now require specialized skills...The rider experiences no marked improvement...//   

       Yep, [+] from me too.
MaxwellBuchanan, Jun 21 2012

       Actually, what would be cool is a bike which can be mounted on a stand as an exercise bike, and which stores the energy as compressed air for the next day's ride to work.   

       I know we've done this before, but compressed air at 300 bar has a potential energy of 0.2MJ/litre. Assuming that a strong hollow frame can hold 10 litres, that gives you 2MJ of energy.   

       Assuming that fairly energetic cycling is on the order of a kilowatt, that gives you about 40 minutes of ride time.
MaxwellBuchanan, Jun 21 2012

       For the average (non-elite) cyclist it's closer to about 0.4kW but that's still enough for some motive power.   

       Tata, the Indian automotive manufacturer, has already done this with a car. <link>
UnaBubba, Jun 22 2012


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