MIT team finds that the ratio of component atoms is vital to performance.
The year was 1944, and the war in Europe was drawing to a close. In a last desperate attempt to blunt Allied air superiority, the German air force, the Luftwaffe, rushed the world's first jet-powered fighters into combat.
At just under 600 miles per hour, the twin-engine jets were 100-150 mph faster than the best Allied propeller-driven fighters. But it was a case of too little too late, and the jets had virtually no impact on the war's outcome.
Still, the engine produced by the Germans to power these aircraft, the Jumo 004 turbojet, created intense interest among American aircraft engine designers. About 6,000 were produced in various versions, but most were destroyed during the war.
After the war, a dozen or so found their way to the United States, and it was one of these that caught the eye of Yanni K. Tsipis when he came to MIT on a field trip last summer.
Yanni, 16, is the son of Dr. Kosta Tsipis, a physicist who directs MIT's Program in Science and Technology for International Security. A junior at Concord Academy (his favorite subjects are physics and German), Yanni has long had an interest in World War II and particularly the air war.
"I was at summer camp at Brandeis," he recalls, "and we went to the Gas Turbine Lab at MIT in the Department of Aeronautics and Astronautics." In the basement of Building 31, he said, "they took us past this engine--the Jumo--and I recognized it immediately.
"It was in bad shape. It was badly corroded, covered with dirt and oil, and it was missing a lot of pieces.
"I thought it was a real shame, having the engine just left there to rot, because I knew how extremely rare it was-there are only eight or 10 in the whole country. It occurred to me then, what a really great project it would be to restore it."
After thinking about it over the summer, Yanni contacted Professor Alan H. Epstein, associate director of the lab, and got permission to perform a restoration.
How did the engine get to MIT in the first place? "I have no idea," said Yanni, "nor does anyone else seem to know where it came from. It adds a little mystery to the project, which is nice."
Yanni has put in about 55 hours on the engine so far and expects it will take about 200 hours to finish.
"I've been cleaning, burnishing and removing the corrosion," he said, "but now I'm getting into replacing some missing pieces--at this stage mostly wiring, pipes and screws--and restoring pieces that are in bad shape. My main goal is to go beyond a mindless cleaning and also to delve more into the technical aspects."
Yanni said he has contacted "many, many people"--mostly through the Internet-- "and several have sent me documents about the engine, both from German and American sources."
He is using the documents, he explained, to understand the technical aspects of the engine, to find what parts are missing, and also what is involved in replacing them.
According to Yanni, the Germans assigned a group of mostly young engineers to develop the engine near the start of the war in 1941. One of those engineers, Dr. Anselm Franz, he's learned, is now living in Connecticut and Yanni plans to contact him.
While he hopes eventually to restore the engine to a point where it is potentially operational, he has no thoughts of starting it up. "That would be too risky and difficult," he said.
Even during the war, he said, the Germans encountered a lot of production and technical problems with the engine, which had a very short service life. Still, it was much more advanced than one being developed in England.
The only way American pilots could engage the relatively few German jets that did fly, Yanni said, was to attack them when they were landing or taking off.
Throughout the 1950s, he added, most of the jet engine and airframe designs developed in this country relied heavily on plans recovered from the Germans, so the Jumo 400 "continued to have an effect after the war."
A version of this article appeared in MIT Tech Talk on January 24, 1996.