patent drawing of unicycle with training wheels

In a traditional classroom, you have... homework/lecture, homework/lecture, and then you have a snapshot exam. After that exam, whether you get a 70%, an 80%, a 90%, or a 95%, the class moves on to the next topic...And then you go build on that in the next concept. That's analogous to, imagine learning to ride a bicycle. And I give you a bicycle...and then I come back after two weeks, and I say, "'re an 80% bicyclist," so I put a big "C" stamp on your forehead, and then I say, "Here's a unicycle."

—Salman Khan,

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Not a flying car or hovercraft.  Air cars have tires and run on the road like any car.  Instead of a gas engine they have an engine that runs on compressed air.  Instead of a gas tank they have an air tank, like a scuba tank but bigger.


drag racing car run on air

The sky's the limit. Depending on the design, air can make a car putt-putt around town or burn rubber on the race track. Air engines work like steam engines: expansively rather than combustively. This gives them the highly desirable characteristic of maximum torque at starting speed, unlike the gas engine which must be geared down from the high speeds at which it must malfunction in order to not self-destruct.

windmill operates high pressure air compressor


There are three answers for three different types of air car.

Hybrid air cars carry a gas-powered engine and compressor on-board, so their range depends on the efficiency of the system and the size of the gas tank.

Conventional air cars, such as the pneumatic locomotives that were available commercially from about 1890 to 1940, stop at air stations to refill their tanks. These cars can be designed to go 1 to 50 miles between fill-ups, depending on the efficiency of the system, the size and pressure of the tanks, and the ingenuity of the designer.

Free range air cars are powered by ambient heat, a form of solar energy. Such cars are experimental in nature, and getting an inventor to give up his secret is harder than figuring it out for yourself. Hint: absolute zero (if the sun went out, for example) is about 460 degrees below 0 degrees Fahrenheit, or 270 degrees below 0 degrees Celsius. A free range air car is any air car that carries a compressor (or more than one) as its main air supply.


No solar panels, mirrors, lenses or other solar collectors are involved. The Earth's atmosphere is a gigantic air tank containing over four quadrillion tons of compressed air at the pressure of 14.7 pounds per square inch at sea level, or less on top of Mount Everest.

If not for the sun's heat, the oxygen, nitrogen and other components of our atmosphere would be mixed with the rocks and soil of the earth as solid substances. The sun adds about 500 degrees of temperature (Fahrenheit) to the air and all this heat is stored in air. When air is pushed into a tank, that is, compressed above atmospheric pressure, its internal energy (heat from any source, mostly the sun) becomes available to operate an air motor.

4 steps to air car freedom


Compressed air cars have been around since the 1880s. Hundreds of patents have been granted to inventors of air cars. After about 1930, the term "air engine" was no longer used in engineering textbooks, and the pneumatic locomotives which once proliferated in mining were mostly replaced by electric conveyances which had not been safe or reliable until then. It was becoming apparent by 1930 that compressed air was going to displace the fuel industry with free solar energy, and sometime during the second world war it became unpopular in engineering circles to mention compressed air as an energy carrier of any importance. Gas was cheap at the time, and there was little apparent need to consider alternatives; we ate what the oil companies fed us, and now we are paying 20 times more for a gallon of gas than I used to pay when I first started driving 40 years ago.

The short answer: we are letting profit-oriented mega-corporations make our decisions for us, instead of thinking about what we could be doing to improve our conditions and the condition of our environment. And why not? Middle-class people are still living like aristocrats compared to most of the world.



Electric cars use power generated by coal, nuclear power, and dams. They require hours to recharge. Batteries must be replaced frequently, and have no place to go when they die. Materials used in conventional batteries are caustic and poisonous. Materials used in exotic batteries are not necessarily more abundant than petroleum. Batteries are many times heavier than air tanks.

Hydrogen cars use combustion engines, which are Rube Goldberg devices that an enlightened public would refuse to buy. Hydrogen must be stored in an altered form to keep it from being many times more explosive than gasoline or diesel. Hydrogen cars exhaust water, which will freeze on the road in cold weather and increase the humidity of the atmosphere, effecting the climate. Hydrogen is more costly to produce as a fuel than fossil fuels. How do we propose to produce hydrogen in factories powered by hydrogen? I thought this was a joke until Pres. George W. Bush endorsed hydrogen cars. Then I KNEW it was a joke.

The simplest solution is the best solution. Air tanks don't really wear out or explode; not like batteries do, and nowhere near as often. Air engines require less frequent oil changes than gas engines because they run at low temperatures, and can be designed to be almost lubricant-free. No chemical reactions take place in the compression and expansion of air. Air compressors actually clean the air by filtering it, and no air motor increases greenhouse gases. All the necessary technology has existed for 100 years. Simple solutions cost less. Homespun mechanics will be back in business. High tech = high cost. Compressed air is solar energy. Solar energy is free energy.

I believe that a new cheap way to compress air is essential in order to prevent the need for air cars to carry big high pressure tanks. The tanks are safe, but the problem is that filling them quickly, especially if there is any water in them, can make them dangerous. People are always in a hurry and technology in poor countries is imperfect, so I think the free range air car should be everyone's eventual goal in this field. An air car with no compressor on board is stupid.

Please address other technical questions to our online air car forum.