Today, the life and the death of the Akron. 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.
We've heard so much about the
Hindenburg: How the great hydrogen-filled
dirigible caught fire in Lakehurst, New Jersey --
how that spelled the end of the hydrogen dirigible.
Few of us are aware that a British dirigible
crashed and burned in France, seven years earlier,
with a much greater loss of life.
Nor are we very aware that a helium-filled American
dirigible, almost as large as the
Hindenburg, was wrecked four years before
the Hindenburg burned, with twice the loss
of life. The burning of the Hindenburg in
1937 was, in fact, a last gasp of a dying
technology.
That British dirigible, the R101, had been
one of a pair of large airships. By the time it
burned, the American Navy had already turned to
helium for its big airships. Helium is inert, and
it was plentiful in Kansas and Colorado.
However, consider this: The molecular weights of
hydrogen, he-lium, and air are two, four, and
twenty-nine. Helium is twice the weight of
hydrogen, so we lose roughly seven percent of our
lifting ability when we switch from hydrogen to
helium. A helium dirigible has to be seven percent
larger, to lift the same load.
That loss was offset by a subtler advantage,
related to helium's non-flammability. Gasbags in a
hydrogen dirigible had to be kept away from
anything that might trigger combustion with oxygen
in the surrounding air. In a helium dirigible,
active equipment could be placed inside
the huge cigar-shaped body. The diesel engines, for
example, didn't have to be mounted in external
pods.
So the Goodyear Company set out, in 1924, to build
two great sister dirigibles for the Navy -- the
Akron and the Macon. Only a tad
smaller than the Hindenburg, they could
actually function as embryonic aircraft
carriers. Each could carry four Curtis
Sparrowhawk biplanes. They were launched
and retrieved by means of a trapeze apparatus,
which swung out below the dirigible.
A Goodyear booklet, put out in 1925 and then
renewed annually, celebrates the construction of
these once-largest dirigibles in the world. It
lovingly displays their light, almost buoyant,
duralumin frame. It boasts how their propellers
could be swung 180-degrees, to reverse the
dirigible's direction. But the booklet keeps quiet
about their airplane-carrying ability.
Nor does it speak of the delicacy of those early
dirigibles in a gale. In 1933, a storm caught the
Akron off the coast of New Jersey. The
resulting crash killed 78 people. Two years later,
a storm caught the Macon off Big Sur,
California. Only two people died that time, but the
Navy gave up on dirigibles.
Only after all that, did the Hindenburg
burn. And it did so with a surprisingly small loss
of life. However dramatic that disaster was made by
the new radio, and by the new movie newsreels, it
only underscored the passing of a dying technology.
Dirigibles simply were not yet robust enough to
survive -- at least back then, in the 1920s and
'30s.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
H. Allen, The Story of the Airship. Akron,
OH: The Goodyear Tire & Rubber Co., 1925 (1931
ed.) (My thanks to Sims McCutchan for lending me this
remarkable old book.)
The following websites are also useful here:
The Era of the Dirigible
Akron and Macon
The Akron
The Crash of the Macon
The
Akron in flight over Washington, DC
(from a Library of Congress
photo)
A
Sparrowhawk in flight, photographed from
the Macon
(U.S. Navy Photo)
The Engines of Our Ingenuity is
Copyright © 1988-2003 by John H.
Lienhard.
