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airBike

Compressed Air for Bicycle Acceleration and Hill Climbing.
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My idea is to use spikes of surplus inertia (going down hill, or breaking) to charge an on-board air bottle – then, when you need a boost, engage a small pneumatic motor to add power to the wheels.

The compressor/drive device can be fitted in to a front wheel hub, and connected to the storage system via rubber pneumatic hose. The compressor can be engaged manually with a lever, or a with mercury switch that senses it is going down hill.

It would also be cool if the operator could charge the system by hand when stopped at traffic signals or rail crossings. This could help the rider reclaim some of the lost time and help keep the metabolism going while waiting for the train to go by.

The 1st prototype, as tradition would have it, would be brutally ugly, with hoses, levers, an air bottle or two bungeed to the rear rack, oh, and a retro-fitted impact wrench fitted to drive the front wheel. The form that would follow this hopefully functional beast would be a thick tube bicycle frame that can be used to store the compressed air, with frame members connected by discreetly hidden tubes to distribute the pressure between the top tube, down tube, and a specially designed seat tube. A rear hub can be manufactured to include the compressor/drive assembly, as well as accommodate a cassette. (Methinks a planetary gearing spec would cause the engineers to get violent :) Recumbent and chopper frames would be able to store more air (longer top and down tubes), and they would need this function more often as these bikes are not good at going up hill.

The mother of this idea is my two bad knees, not energy conservation. Experienced cyclist know the best way to go down a hill is at top speed in the highest gear, because they know they’re going to have to pay for that downhill ride on the return trip when they have to climb it. My problem is that when my knees are acting up, I have trouble getting up hills even in the lowest gears. There are electric motors for this; however, I find the added weight of the lead-acid batteries un-appealing.

1st2know, Nov 29 2003

Compressed air motor for a bicycle. http://www.inventor.../vedres/vedrese.htm
[2 fries shy of a happy meal, Oct 04 2004]

Compressed Air Vehicle http://www.theaircar.com/
Not completely off topic [Worldgineer, Oct 04 2004]

baked Bicycle_20Stirrups
bike works on compressed air [pashute, Jul 05 2006]

almost exactly described as the first prototype http://www.instruct...E5OMNXCU2REP2860RS/
I think this guy read your idea. [bleh, Aug 05 2007]

[link]






       Good 1st, 1st. Welcome to the HB. +
lostdog, Nov 29 2003
  

       hb: so you combine this with an oven/cooler.
12k: are you sure you can store enough energy in a light enough contraption to fit on a bike?
DrCurry, Dec 01 2003
  

       Doc C: // are you sure you can store enough energy in a light enough contraption to fit on a bike? // In short: Nope - I have a 5 gallon storage tank that weighs ~12 lbs. Thats a lot of lbs for a bike.   

       The marketable version of this contraption would use the bikes framing system as a storage bottle. Special fat oval tubing would be needed. I would guess that a standard diamond frame with fat tubing would hold ~4.5 liters at 120 psi. In order for the motor to be meaningfull, it would have to provide 100 watts of power for about 100 yards on flat land. As soon as I learn how to convert air pressure and volume to watts I'll have a better idea of this gizmos feasability.   

       Human: Good point on condesation - The frames could disentegrate from the inside/out without warning!- I'll add an internal anti-corrosive coating to the specs as well as a drain valve on each of the frame members.   

       Does anybody know if Titanuim would be susceptable to this type of corosion?   

       BobbyC & LDog: thanx!
1st2know, Dec 01 2003
  

       I was really hoping this was going to be a cousin-idea to the airguitar, but its still good.
luecke, Dec 01 2003
  

       //heat bleeds off//
There went a lot of the energy.
  

       Your tanks will be huge and heavy. You'll be pedalling hard downhill, and then work to get that thing back uphill when your air runs out. This is NOT a complaint! I voted for this idea on the premise that it's a bike designed for excercise. It would be easier to just add drag to an ordinary bike, and release it for uphill rides. But then it wouldn't be an AirBike.
Amos Kito, Dec 01 2003
  

       [AK] I disagree. I once saw a show about a compressed air vehicle that used 5 gallon plastic water jugs for compressed air and were able to drive quite a distance on a few of them. If extra tanks are needed, they may not need to be heavy.
Worldgineer, Dec 01 2003
  

       //plastic water jugs//   

       Pretty cool. If the bike used clusters of liter soda bottles, you could replace the tanks inexpensively. But I'd probably pressurize them before the trip, even if there's an onboard pump.
Amos Kito, Dec 01 2003
  

       //Where the hell does the salad go?//
  

       Unfortunately, this model does very little to dry salads, however, as [humanbean] points out, there will be some refrigration effect as the air expands - The wheels can be modified to hold cream, sugar and vanilla, doubling as a mobile ice-cream maker. This will add another $100US to it's MSRP! And they'll pay it too, 'cuz who wouldn't want to make ice cream while they're dodging SUV drivers talking on cell phones.(the least productive multitaskers - IMO)
1st2know, Dec 02 2003
  

       Good idea. I hate peddling up hills. The increased wind resistance and weight from the storage tanks, made of whatever, may be a hinderance.   

       Only would work if you go downhill alot more than go up.   

       You could cool the heat with a fluid running through tubing and a vest that you wear. It would cool you down and heat the tanks up.   

       I can just picture going down the 1 mile hill with a hose poked somewhere getting bigger and bigger and bigger until you explode. Very Arcade like ;)
clafever, Jan 21 2004
  

       I recently had the same idea. I did a google search and it brought me back to the bakery and another site I frequent, Instructables. Its good to know I'm in the right places.   

       //The 1st prototype, as tradition would have it, would be brutally ugly, with hoses, levers, an air bottle or two bungeed to the rear rack, oh, and a retro-fitted impact wrench fitted to drive the front wheel. //   

       Check the link to instructables. Thats almost exactly what these guys built. Except they used the imact driver on the back wheel. And theirs doesnt compress air, just uses it.
bleh, Aug 05 2007
  

       Is Ford's (?) regenerative brake energy storing oil compression system still available? It was only on their 250 series pickups I recall.
M Carter, Jan 06 2008
  

       Get ready for this.   

       4.5 litres at 120PSI   

       4.5 litres = 4.5*10^-3 cubic metres   

       120PSI = roughly 827, 000 pascals   

       Energy = Pressure * Volume (Newtons/metre^2 * metre^3 = Newton*metres)   

       Energy = 3721.5 Joules   

       At perfect conversion (with pneumatics, you'll never get anywhere near unity), this ammounts to accelerating you and your bike, if total mass = 100kg, to 8.6 m/s, which is 31 km/hr.   

       Which is the same as raising your 100kg to a height of... 3.7 metres. Not much of a hill.   

       Although, if you could sort the pump out, I can't see why you're stopping at 120Psi... Even an ally frame will easily hold much more than 120. Except for the whole riding around a highly pressurised, significantly fatigued bomb thing.
Custardguts, Jan 07 2008
  

       bah, I was gonna post something like this, but figgered it was already done; only difference is I was using hydraulic fluid of some sort, and you could disengage the pedals from the wheel and charge it while your at a red light.
FlyingToaster, Jan 08 2008
  

       A bicycling magazine column I once read described this idea very well. It was an April Fools joke, though.
baconbrain, Jan 08 2008
  
      
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