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copyright © 2011 Scott Robertson

Robert Cady Burt's air car was a good example of two air engine technologies: closed cycle (recompressing air exhausted from engine) and hybrid (on-board compressor run by small gas engine).  His patent is explicit and scientific, a good document to study.

This picture of an air car from the olden days appeared in Compressed Air Magazine several years ago along with a promise to publish an article "soon" about air cars.  Soon didn't happen before the magazine was discontinued after 104 years.

My goal with this design was to show an infallible means of injecting atmosphere into a pressurized tank without dissipating the energy already in the tank.  The drawing shows a compressor in a full tank boosting tank air which drives a jet pump to induce atmosphere into the tank through a double bank of check valves.  A Roots blower supercharges the atmospheric intake line.  Both compressors are driven by an air engine using air from the tank.

During the 1890s, General Herman Haupt spearheaded a drive to make air cars a reality.  He supported the work of inventor Robert Hardie, whose air powered locomotives ran on the streets of New York City for several years.  This Scientific American front cover shows the 1500 horsepower compressing station (steam-powered) that was built to provide compressed air for the Hardie locomotives and for the Hoadley-Knight locomotives.  The locomotives' tanks could be filled in a few minutes at the air station.

From U.S. Patent #2,030,759 (1936).  Bob Neal was a shoemaker from Arkadelphia, Arkansas who had to take his engine to the patent office to prove that his invention was not a perpetual motion machine; he was granted a patent based on the fact that his engine worked.  The Pneumatic Options Research Library catalog is full of information related to our search for how it was possible for a series of check valves to allow low pressure air to be pumped into a high pressure air tank against a very small resistance.  See especially the Acoustic Power section.

Bill Truitt is shown here holding up a picture of the air car he built in 1920.  He perfected his design in the 1970s and gave the rights to NASA and the Army.  Bill was from McKees Rocks, Pennsylvania.  His design disclosure was fairly complete with the exception of one or two aspects which he said were top secret.

I built this go-kart in the late 1980s.  It consisted of a scuba tank, an old wood boring drill, and a valve.  From a dead stop headed up a steep hill, it accelerated so fast that it was hard to steer.  On a straight, flat sidewalk its range on a scuba tank of 125 psi air was about 25 feet.  This is the only air car I have built in 24 years of doing research, a situation which I am eager to correct.

A photo of the guest register of the North Star Gold Mine, January 1, 1899.  Edward A. Rix was the founder of Rix Compressor Co., which still exists in Oakland, California.  He designed air powered locomotives for the gold mines in Grass Valley, California, and held dozens of patents on pneumatic machinery.

Our catalog contains many hundreds of pages of information on the behavior of waves in compressed air in compressed air and other fluids, based on our search for the explanation behind Bob Neal's mysterious equalizer, which we call the Magic Valve.  This diagram was made for us by a mechanical engineer who got us started on the search for the sound wave solution when he suggested we look into the pulse jet engine.  The diagram illustrates the building-up of pressure because of the reflection of compression and rarefaction waves in a closed-end cylinder of the properly tuned length.

The founder's concept design for a linear air engine/compressor unit with interheaters to absorb ambient heat and compression heat.  This type of air engine was patented by Charles B. Hodges in 1907 and his invention was sold to coal mines in the U.S.  European designs took his two-stage engine a step further by adding a third stage, and were able to increase the driving range of a tank of air by 60%, using ambient heat to expand the engine's air supply by reheating expanded air between piston stages in order to increase its energy content.

During the 1890s, General Herman Haupt championed the air car cause by finding investors for Robert Hardie's locomotive design for street transit.  One of the concepts proven by their effort was that of regenerative braking, that is, using compressors to slow the vehicle down while heating and compressing the tank contents to increase the range.

This 30-foot diameter Pelton water wheel was used in Grass Valley, California to run a 1000 horsepower compressor that provided tool air and ventilation to two of the largest gold mines in the world.  The spokes of the Pelton wheel are seen in the background.  It was one of the largest water wheels in the world; Mr. Pelton lived a few miles away in Camptonville.  We'd like to see you generate gasoline or diesel fuel with a jet of water piped in from Wolf Creek.  The shape of the water cups was inspired when Mr. Pelton squirted one of his cows in the face with a hose.  It doesn't take a rocket scientist to understand the simple ideas in the Pneumatic Options Research Library catalog.

Terry Miller invented the term "air car advocate".  This photo shows him being driven in circles by the founder of Pneumatic Options,  who compiled Pneumatic Options Research Library and AirCarAccess.com, the world's largest collection of information on compressed air automobiles.  Terry showed his air car from coast to coast, including Times Square, and I learned of him from an article in People Magazine.  This photo was taken by Terry's wife at the Wichita Energy Expo in 1985.  While the electric car at the booth next to us sat idle, we gave free rides on Air Car One nonstop for three days.  People love air cars!

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