1717

Facing the Maelstrom

by
Scope Correspondent

At 4:20 AM on September 3, 1925, a colossal airship of aluminum, silk and helium—over two football fields long—floated over the quiet town of Caldwell, Ohio. Yet from his perch a third of a mile up, Lieutenant Commander Zachary Lansdowne was on edge. He’d been roused from sleep by his crew; the weather had gotten worse, sandwiching the dirigible between a nasty headwind from the south and brewing storms to the north. But he decided to stick to the plan, keeping her on a west-southwest line. There wasn’t any immediate threat, and besides, people all over the Midwest had anticipated the USS Shenandoah’s arrival for months. Changing course would disappoint the admiring crowds awaiting them.

Mother Nature, however, didn’t share this enthusiasm. Above the ship, boiling, dark clouds formed a wall to the north and northwest, engulfing the Shenandoah in a violent squall. For thirty frantic minutes, Lansdowne and the crew did everything they could to right the ship, but to no avail. By sunrise, fourteen of the ship’s forty-three crewmembers had perished; the vanguard of American aviation—only two years old—was smashed to pieces on the foothills of the Alleghenies.

As soon as he heard about the crash, Jerome Hunsaker DSc ‘16 must have gone numb. The Shenandoah was the first rigid airship he had conceived, as a designer for the U.S. Bureau of Aeronautics, and he had strived to make it the best ever made. Having obtained MIT’s first doctorate in aeronautical engineering, Hunsaker was used to working on the cutting edge: not only did he employ new aluminum alloys and state-of-the-art hull designs, but the Shenandoah was also the first rigid airship ever to buoy itself with helium instead of hydrogen, making it much safer. Even so, Hunsaker’s finest creation, along with fourteen lives, had been lost to the winds. What had gone wrong?

After two agonizing weeks without a word from Navy brass, Hunsaker finally got first-hand word from his colleague Charles Burgess, who passed along that “a local ‘twister,’ or maybe two of them, caught the ship,” tearing the Shenandoah in half amid the extraordinary turbulence. Hunsaker and Burgess took some solace in this; everyone knew airships couldn’t handle winds at those extremes, making the ship’s loss regrettable but no one’s fault.

In the Shenandoah’s case, however, the devil was in the details. Survivors’ testimonies were “extraordinarily contradictory,” given the chaos of the Shenandoah’s final minutes. Perplexingly, the cables holding Lansdowne’s control car to the hull had snapped at some point, causing most of the casualties when it plummeted to the earth. And several months before, the Shenandoah’s crew had removed some of the ship’s automatic gas valves—with the begrudging approval from Navy higher-ups—potentially undermining the ship’s emergency systems in an effort to save helium and cut the airship’s weight.

Once the Navy scrambled to form an inquiry on the crash, it was clear that only one man would be suitable as the investigation’s lead technical adviser: William Hovgaard, MIT professor of naval construction. A stalwart of the MIT community and an expert on hull design, Hovgaard—renowned for his penetrating insight—was unusually experienced with complex legal inquiries, having testified in civil suits involving the losses of the Titanic and the Lusitania. And not only did he help advise Hunsaker and his colleagues during the Shenandoah’s design, but he also mentored and befriended Hunsaker while Hunsaker was a student at MIT. Getting the investigation right was not only a professional duty—it was personal.

From September through the end of 1925, Hovgaard dissected the crash from every conceivable angle, sifting through the Shenandoah’s surviving instrumentation, weather reports, and the reams of testimony from the surviving crew. By mid-December, he had finally reconstructed the likeliest chain of events during that fateful September morning.

At 4:35 AM, the Shenandoah’s navigator noticed he couldn’t control the ship’s altitude. To stall the rise, Lansdowne and his crew sprang into action, cranking up the ship’s engines and pointing the airship’s nose downward, but the ship continued to rise. Increasingly at the mercy of the winds and with two engines overheating, the Shenandoah’s crew braced itself. But for an unnerving six minutes, things calmed down; in fact, they even began gently descending.

Then suddenly, a second, even more violent gust of wind threw the Shenandoah up to 6,000 feet, rolling and pitching the ship uncontrollably, snapping wires and tearing holes into the ship’s outer skin. Desperate to get out of the maelstrom, they dumped over 4,000 pounds of water ballast, but to little effect; the Shenandoah was pushed into an up-and-down death spiral before getting ripped in half from the starboard side, cleaving the control car from the rest of the body. By 4:52 AM, the Shenandoah lay in pieces on the fields of Caldwell.

After autopsying Hunsaker’s creation, Hovgaard concluded (as Burgess had suspected) that the intense winds that so buffeted the Shenandoah were the primary causes of the crash. Hovgaard, though, urged that the crash be used as a heuristic for improving both weather services and hull designs. Crashes like the Shenandoah’s were “not necessarily inherent in the art,” Hovgaard concluded, “but follow from the failure to realize the magnitude of the difficulties” around lighter-than-air flight—a problem, in some sense, that Hovgaard was urging his former student to take up and solve.

But in spite of Hunsaker’s best efforts, solving the problems exemplified by the Shenandoah proved impossible. In his later role as vice president of the Goodyear-Zeppelin Company, Hunsaker worked tirelessly to popularize airships, none more than the Navy’s next airships, the massive USS Akron and USS Macon. Debuting in 1931 and 1933 respectively, Hunsaker touted the sister ships, whose design and construction he oversaw, as the safest ever made. He’d done everything he could to ensure it: They were stouter and sturdier than the Shenandoah, rendering them impervious to squalls—or so he hoped. Mother Nature, however, disagreed. By 1935, both ships were destroyed in thunderstorms, killing 75 and forever shattering both the Navy’s airship program and Hunsaker’s conviction that airships would crisscross America’s skies. In need of a change, he left the Goodyear-Zeppelin Company in 1933, making his way back to MIT to become the head of MIT’s Departments of Mechanical Engineering—and, later, the Department of Aeronautical Engineering.

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