PROFESSORS' 'HINDENBURG' RESEARCH FEATURED ON DISCOVERY CHANNEL

When the German airship Hindenburg exploded into a ball of flame at 7:35 p.m., on May 6, 1937, while attempting to land in the midst of a light rain and a sky filled with moderate electrical disturbances at Lakehurst, N.J., it was considered one of the world's greatest tragedies.

Although several investigations have been conducted in the ensuing years, the cause of the crash, which killed 36 of the 97 passengers on board, remains a subject of debate among scientists and amateur investigators. Recently, four UD researchers lent their scientific expertise to the ongoing search for answers in a program that aired in October on the Discovery Channel, which has a worldwide audience.

In their investigation, UD scientists sought to examine the crash from the point of view of modern forensic engineering, a science dedicated to discovering why and how accidents happen. The on-camera UD team included Ian "Rick" Hall and Roger Stahl, mechanical engineering. Off-camera expertise was provided by Len Schwartz, mechanical engineering, and Douglas Buttrey, chemical engineering.

"The filming crew had spent several days filming at the old Lakehurst airship base in New Jersey," Hall said. "They picked the Department of Mechanical Engineering at UD because of our high-quality labs and personal connections with our faculty."

What modern day researchers want to know is why the rear section of the aircraft, which measured some 135 feet across at its greatest diameter, caught fire as the ship floated 291 feet above the tarmac and less than 600 feet from the mooring mast at which it was seeking to dock.

Theories include the weather. Although atmospheric conditions were ripe for static electrical discharge, the ship had been struck by lightning several times before and had survived.

Another possible cause is sabotage, based on the popular theory that someone may have placed a timed explosive device along the ship's gas ventilations shaft, which would account for eyewitness accounts of seeing a loose piece of the ship's covering and a blue flame that spread along the back of the ship just before the explosion.

Design problems also have been suspected, with many investigators giving credence to the theory that the outer skin of the huge aircraft, a portion of which was seen flapping in the wind, was the real cause of the disaster.

An additional theory is that there may have been a stress failure in one or more of a series of steel cables that held the 804-foot ship together.

"One new idea to me is that a cable snapped and caused a spark that may have ignited the hydrogen in the airship," Hall said.

To help determine the validity of this theory, researchers used the Department of Mechanical Engineering's world-class testing equipment, including its electron microscopy facility, to repeatedly cause stress failures in several representative steel cables similar to the size and composition of those used in the Hindenburg.

"The conclusions of the program were rather surprising," Schwartz said. "There were many theories for why the Hindenburg crashed, including lightning and sabotage (it had big swastikas on its tail). Based on the forensic examination, it appears that a likely cause is a simple mechanical failure, associated with inadequate maintenance." Schwartz, who arranged for Robert Kadlec, the program narrator and highly respected forensic scientist, to visit UD, was impressed with the professionalism of the Discovery film crew.

"They make their points in a very efficient manner," Schwartz said. Stahl, who appeared on segments of the program with Hall, said the experience with the Discovery program reminded him of a conversation he once had with his father.

"He remembered the Hindenburg from his experiences as a youth," Stahl said. "His uncle had a beach house off Point Pleasant, N.J., about 25 miles from Lakehurst, and he had been visiting there when the Hindenburg went down."

Stahl said he also enjoyed working with the film crew and some of the original evidence used at the time of the incident to determine what might have caused the Hindenburg disaster, including some original black and white photos of the explosion that were used as evidence in the original investigation.