The Burning Question About the Hindenburg

From Popular Mechanics

It was nearly dusk on May 6, 1937 when the 804-foot, swastika-marked, cigar-shaped German airship LZ 129—the Hindenburg—floated into the Lakehurst Naval Airstation in New Jersey. The crew, who had been flying for three days since leaving Frankfurt, realized they needed to land fast to avoid a rapidly approaching storm. At about 7:20 p.m. they dropped the forward landing ropes and began the mooring procedures. Three minutes later, the Hindenburg burst into flames.

Within an awe-inspiring 34 seconds that was entirely captured on film and caused radio broadcaster Herb Morrison to cry "Oh, the humanity!", three football fields worth of hydrogen-filled airship burned until it was nothing more than a white-hot metal skeleton. Thirty-six people died on that May day in the fields of New Jersey. Another casualty: The future of lighter-than air travel.

Today marks the 79th anniversary of the Hindenburg disaster, a fiery catastrophe we've all seen replayed dozens of times. Yet even now we still don't know for sure why the airship was quickly engulfed in flames. Scholars have continually debated the potential causes, but the lack of new evidence—since most of it was destroyed in the fire—has made this task speculative. One thing is for certain: The Hindenburg disaster still fascinates us.

The Deadly Years

Long before the Wright Brothers, there was Count Ferdinand Graf von Zeppelin. A German lieutenant, he first learned about air travel in the 1860s when President Lincoln commissioned him to be an observer with the Union Army during the American Civil War. Both sides utilized hydrogen-filled reconnaissance balloons, though the Union did it much more effectively thanks to Thaddeus Lowe.

Returning from America, Zeppelin drew up his first designs for a rigid airship, hoping to boost long-range travel to civilization's benefit. It took several decades, but in 1900, Zeppelin debuted the world's first working hydrogen-powered airship when he captained LZ-1 over Germany's Lake Constance, three years before the Wright Brothers' 1903 maiden voyage. Zeppelin spent the rest of the decade improving his design through subsequent models. By 1910, zeppelins were used for both passenger travel and military purposes.

Despite the German public and military's enthusiasm over this futuristic transportation, the looming safety issue was obvious. The ship's main fuel, hydrogen, is flammable, especially when mixed with oxygen and any electric spark. If the hydrogen were contained, it could be used effectively and safely. If not, disaster can happen. In 1908, Zeppelin's fourth design, the LZ-4, crashed and burned in front of hundreds of spectators after tree branches ripped the hydrogen bags. In October 1913, the gas inside of a LZ-18 built for the Imperial German Navy was overheated by the sun. Attempts to release hydrogen resulted in an engine fire, killing all 28 people on board. During World War I, Germany employed the mammoth and scary-looking Zeppelins while air-raiding London in hopes of psyching out their enemies. It worked: Londoners nicknamed them "baby killers" after a zeppelin dropped a bomb that killed a three-year-old girl. But the psychological warfare was less effective once the British Flying Corps realized the airships' weaknesses. A few well-placed bullets later and the Zeppelins became falling fireballs. Zeppelins were involved in dozens of fires and accidents, many of which were deadly or related to combat.

It wasn't like only the Germans had this problem, either. In 1922, the United States Army bought its own hydrogen-powered airship from Italy, the Roma. It made several flights throughout Europe and America, including one with the US Ambassador to Italy. On February 21, 1922, the Roma capsized over Norfolk, Virginia and nose-dived back to Earth. The crash could have been a lot less severe, but the airship hit an electric wire on its way down, igniting the 11 hydrogen cells on board. The Roma burned in a matter of seconds, horrifically killing 34 of the 45 people on board (most of the survivors jumped). After the accident, the United States vowed never to use hydrogen-filled airships again—only helium.

The Hindenburg

The hydrogen-filled Hindenburg was the crowning jewel of the German Zeppelin fleet. When it was completed in 1935 it was the largest and longest aircraft ever built. The airship was intended to be designed for helium, but the United States held (and still holds) dominance over helium reserves, and enacted the Helium Control Act of 1927, preventing export to Germany.

During the Nazi party's rapid rise to dominance, it co-opted the Hindenburg as a symbol of national pride and Third Reich power. Like its sister ship the Graf Zeppelin and all other German aircraft, it was required by law to carry a symbol of the Nazi party, so a bright red-and-black swastika was painted on the tail. The Hindenburg's first flights took place in 1936. The airship acted as a roving Nazi propaganda tool, announcing over loudspeakers support for the Fuhrer and dropping leaflets promoting the remilitarization of the Rhineland. It flew over the Nuremberg Party Rallies and the 1936 Olympic Games in Berlin. And then came its fateful voyage to America.

Today it's hard to imagine the United States allowing a swastika-branded Nazi ship to venture across our borders and dock at a Navy base in New Jersey. But that is exactly what happened. "When the Graf Zeppelin came to the United States (in 1933)... it was the first time the swastika was flown to the United States," says Dr. Cheryl Ganz, who is a Hindenburg scholar, co-curator of Fire & Ice: Hindenburg and Titanic (2012), and the National Postal Museum Smithsonian Institution Curator Emerita. "It is still shocking to me that in 1936... people knew bad things were going on over (in Germany)... but there were no big protests about the swastika on the Hindenburg." Why not? For one thing, she says, Zeppelin's company president (and a Zeppelin captain himself) Hugo Eckener made it very clear he was a businessman and engineer, not a Nazi. Additionally, Lakehurst was a Navy property and the contract to land there was between the American Navy and the Zeppelin operating company. It was a business deal that allowed the Navy to control who came in and out.

Perhaps the biggest factor in America's agreement to allow the Hindenburg to dock at Lakehurst, though, was that the ship was such an engineering and technological marvel. Despite being 3.5 times the size of a Boeing 747, it could move at 84 miles an hour. That's not speedy by today's standards, but it means the zeppelin could make the trip across the North Atlantic in two and half days instead of an ocean liner's typical five days. It could fly up to 70 passengers and 50 crew members in style, complete with sleeping quarters, a writing room, a dining room, a lightweight aluminum grand piano (removed prior to the 1937 season) and a pressurized smoking room which the bartender owned the only electric lighter allowed on the ship. It had long, beautiful bay windows that gave passengers panoramic view of their surroundings. No wonder tickets were expensive, costing about $450 one way (equivalent to nearly $8,000 today).

In addition to passengers, the Hindenburg also carried mail across continents. More profitable to haul than freight or additional passengers, mail provided the Zeppelin company additional revenue. "On the first flight of the Hindenburg, Eckener... went to New York City to talk at a big international stamp show and thanked the collectors for financially supporting Zeppelin," says Ganz. It is estimated that hundreds of thousands pieces of flew on the Hindenburg over the course of its 63-flight, 14-month run starting in 1936, a run that included 10 trips to Lakehurst and eight trips further south to Rio De Janeiro.

Oh, the Humanity!

On the fateful May 1937 trip, 36 passengers boarded the Hindenburg in Frankfurt accompanied by 61 officers and crew. While the airship took off on time, it ran into delays crossing the Atlantic due to headwinds and approaching storm fronts. The crew radioed Lakehurst announcing they would delay their arrival time by 10 to 12 hours, from 6 a.m. on May 6 to late afternoon. This allowed the Hindenburg to float over the Boston and New York City skies during daylight hours, which was not part of the original schedule but created rather unbelievable images that look like something out of the Philip K. Dick novel Man in the High Castle.

The airship arrived at Lakehurst at about 4:15 p.m., only to begin circling again because of bad weather. By 6:15 p.m., the storm had subsided and Lakehurst's commanding officer told the ship's captain to land as soon as possible to beat another approaching storm. Shortly after 7 p.m., the Hindenburg neared the mooring mast, but the tail felt heavy and the winds prevented the ship from being level. In response, the captain released hydrogen from cells 11 to 16 for 30 seconds in hopes of reducing the buoyancy of the bow and keeping the ship in level trim. When this didn't level the ship, the captain ordered three water drops (a releasing of water in spurts) totaling nearly 2,500 pounds in another attempt to level the airship. At the same time, the winds shifted, leaving the airship little room to maneuver. So the crew executed a sharp turn to align with the mooring mast. In the end, it was a lot of adjusting, leveling and quick decision-making that all could been factors what ended up happening. At 7:21 p.m, with the airship 180 feet in the air, the forward landing ropes were dropped. Then, flames.

To this day, no one is quite sure what exactly caused the fire. There are a few things we can be pretty sure didn't happen, Ganz says—evidence contradicts theories such as sabotage, or that the fabric and/or paint started the fire (MythBusters proved this theory incorrect).

There's a laundry list of possibilities related to how loose hydrogen could have ignited. Ganz's personal theory focuses on that sharp turn the Hindenburg made. Inside of the ship, she says, there were rings filled with bags of hydrogen and over 80 miles of bracing wire holding it all together. "If one bracing wire snapped... and as you can imagine a tension wire snapping, it quickly moves, it could have slashed a gas bag... Make that sharp turn with the extra tension on those already taut wires, that is a possibility. For me, that's the most plausible (cause)."

Here's what we know. There was already lots of water on the ground because of the storm and the Hindenburg's water drops. Landing crew members would later say they walked in wet sand and puddles while handling the ropes to pull the airship to the mooring mast. Danger was afoot: When loose hydrogen (perhaps from the slashed gas bag) combines with oxygen gas (present even in small amounts of air), it can be ignited by something as simple and ordinary as static electricity—perhaps from a ground crewman walking in puddles and grabbing a statically-charged rope.

This is exactly what the 1937 Board of Inquiry concluded, with the exact terminology being that a "electrostatic discharge" caused the fire. While we may never know for sure what exactly caused all of these dangerous elements to happen due to the destruction caused by the fire and crash, Ganz is sure that these unanticipated factors are at fault for one of the most famous disasters in history. Says Ganz, "It was a perfect storm."

Thirty-six passengers and crewmembers were killed, but it could have been worse. The huge bay windows allowed many to jump out. A few design elements (which Ganz says were accidental) delayed the fire from spreading for a number of seconds, including a metal ventilation system and bouncy rubber tires. That gave people more time to escape.

Never again did another German airship dock at Lakehurst, though the Graf Zeppelin did continue to fly with hydrogen around Europe. On May 6, 1940, exactly three years after the Hindenburg disaster, the Nazis unceremoniously blew up Zeppelin's hangers in Frankfurt.

Reminders of the Hindenburg remain, however. In New Jersey, at Joint Base McGuire- Dix-Lakehurst, there's the massive hangar that the Hindenburg sat in and a memorial at the exact spot where the airship burned. Every May 6, [link href='http://www.nlhs.com' link_updater_label='external' target='_blank']Navy Lakehurst Historical Society hosts a service that starts at 6:45 p.m. and ends at 7:25, the exact time that the Hindenburg was left as little more than burning rubble.

One can still see the legacy of the Hindenburg in the blimps most often found floating above big sports events. In fact, Goodyear and the German zeppelin manufacturer ZLT Zeppelin Luftschifftechnik combined forces in 2013 to bring back zeppelins. Thankfully, there's a difference between the zeppelins of yesteryear like the Hindenburg and the ones today: They are filled with helium.

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