Engines of Our Ingenuity

No. 743:
A STIRLING FAN

by John H. Lienhard

Click here for audio of Episode 743.

Today, a Scottish minister, a nonelectric fan, and jet planes. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

The other day I visited a distinguished collector of turn-of-the-century technology. I saw all the extraordinary elegance of that age -- music boxes, fine lamps, automatic orchestras.

One item was a non-electric fan. The Lake Breeze Motor Company made it in 1919. It looks a lot like a regular electric fan. But under the blades rides a small kerosene lamp. There are no wires. It's most peculiar.

This Model B Lake Breeze Fan wafted air past me as I scanned the manufacturer's catalog. It cost $22.50 in 1919. Today that'd be like two to four hundred dollars. It wasn't cheap, but listen to some of the printed testimonials:

"Everybody seems to think it is a wonder, as it really is."
"Please return our fan as soon as possible. We are about to suffocate without this wonderful little machine."
"I have a little girl sick in bed with the fever and she is certainly enjoying the fan."
In the shaft that holds the fan is a hidden Stirling hot air engine. The catalog makes no secret of how it works. It offers rich cutaway drawings with details of the mechanisms.

The idea traces to Robert Stirling, a 26-year-old Scottish Presbyterian minister. He had a radical idea. In 1816 he took out a patent on a hot-air engine. Up to then, the steam engine was the only practical heat engine that'd ever been built.

Stirling alternately heated and cooled the air in a cylinder. It had to be large and slow-moving to be efficient. It took a big capital investment. Yet he made it work. A 45-HP working model drove equipment in a Dundee foundry for three years.

The Swedish-American inventor John Ericsson invented his own version of the engine in the mid-1800s. From then on, the idea kept evolving and mutating. People finally simplified it and sped it up by burning fuel in the air as it passes between sets of turbine blades. The modern fan jet is the great- grandchild of the Rev. Mr. Stirling's odd machine.

The Lake Breeze Fan was only a way station in that evolution. As we put in power lines, electric fans quickly replaced it. And, anyway, it had a serious shortcoming. That kerosene lamp dumps heat into an already hot room. The temperature rises even as the dandy little fan dries your sweat.

So nine years later, in 1928, Germany built the first gas turbine. By 1939 they'd flown the first turbojet airplane. And Stirling's invention did at last become a breeze of change that blew away old engines and changed the way we travel the Earth.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


I am greatful to Richard J. Howe for showing me his fully operational Lake Breeze Non-Electric Fan. He also provided copies of the 1919 Lake Breeze Motor Co. catalog and the two relevant patents, Nos. 1,365,206 and 1,420,672. For information about relative costs, then and now, see:

Howe, R.J., Converting the Original Prices of Instruments into Today's Dollars. Journal of Mechanical Music. Winter 1991, pp. 1-13.


The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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