Engines of Our Ingenuity

No. 1507:
LIGHTER THAN AIR

by John H. Lienhard

Click here for audio of Episode 1507.

Today, do you suppose you'll ever get to ride in a dirigible? 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.

Four government agencies met back in 1975 -- NASA, the FAA, the Navy, and the Department of Transportation. They held a workshop to reassess lighter-than-air flight. The meeting took place 39 years after the German zeppelin Hindenburg burned at Lakehurst, New Jersey, and tolled the death knell for commercial airships.

The Hindenburg disaster branded hydrogen as unsafe for buoying these great whales into the sky. Actually what'd been so murderously flammable was the Hindenburg's acetate-soaked fabric covering. But hydrogen took the rap, and it had to be replaced with helium. On the eve of WW-II, we controlled the world supply of helium; Germany couldn't get it, and dirigibles went out of business.

The 1975 workshop didn't just ask whether these gentle monsters should be made to fly again. It also brought to light a stunning array of potential extensions of the old technology -- hybrid airships with airfoil-shaped bodies to add lift in flight; small blimps for urban transport; airships with different shapes; blimps to move large, heavy items that won't fit in airplanes. It dealt with airships for all payloads, ranges, and speeds.

The workshop concluded that the potential for airships was enormous. But it also pointed out that economic feasibility couldn't be determined in a paper study. People, it said, must bite the bullet and attempt commercial ventures to answer that question.

A quarter century later, we see occasional blimps, and no dirigibles, in the sky. Many entrepreneurs responded to the challenge and took the risk. But few who tried to create new lighter-than-air technologies have had much success. Today's skies are filled with advertising blimps. The Navy, which gave up rigid airships in the early 1960s, flirted with the idea again in the 1980s. Then they gave it up a second time. Others have tried to start sight-seeing airship services.

It's the big rigid dirigibles that we dream about. And they have to be built longer than a football field to get a low enough weight-to-volume ratio. The twentieth century began with stately zeppelins crossing the Atlantic and passengers dining in quiet palatial elegance. Can that reemerge in the 21st century? The answer isn't clear. Airships, with their inherently slow speeds, pit our craving for graceful elegance against our impatience. They lay schedules open to the mercy of changing winds.

The dirigible wrote a strange chapter in the history of technology. It's a beautiful machine that's come and gone, but which could yet return. Technology seldom does that. However, I suspect the dirigible was killed neither by the Hindenburg disaster nor by impracticality. Rather, we were distracted by the airplane and by WW-II. The potential is still there, and perhaps our children will, once again, get to ride new dirigibles in the new century.

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

(Theme music)


An Assessment of Lighter than Air Technology. (J.F. Vittek, Jr., ed.) Cambridge, MA, M.I.T. Flight Transportation Laboratory, June 1975.

Two web sites that offer good material on the state of lighter-than-air flight today are:

http://www.hotairship.com/
and
http://spot.colorado.edu/~dziadeck/airship.html

This is a greatly revised version of Episode 75.



Stereopticon image courtesy of Margaret Culbertson

The post-WW-I American Dirigible Akron under construction
An age that we've left behind.


The Engines of Our Ingenuity is Copyright © 1988-2000 by John H. Lienhard.