ARNOLD AIR FORCE BASE, Tenn. -- The reins of the largest single Arnold Engineering Development Center unit completed up to that point were handed to the Center’s operating contractor on Nov. 30, 1953.
On that date, the Air Force turned over the Exhaust Compressor Building, part of the Engine Test Facility, to Arnold Research Organization, the corporation established to maintain and operate AEDC.
The Exhaust Compressor Building contained a battery of six large exhaust compressors, the utilization of which would allow entire turbojet, turboprop and ramjet engines to be tested at simulated altitudes of more than 15 miles above the earth’s surface.
“The six exhaust compressors have been installed to function either as a single unit or independently of each other,” an AEDC news release issued on the day of the turnover states. “They operate at speeds from 2,600 to 4,700 revolutions per minute. Four are driven by 5,000 horsepower electric motors, two by 10,000 horsepower motors, as they create various altitude conditions up to 80,000 feet in the test chambers.”
To mark the turnover, a ceremony was held during which Col. L.E. Cox, engineer with the Tullahoma District of the U.S. Army Corps of Engineers, turned the exhauster building over to then-AEDC Commander Brig. Gen. Samuel Harris. Harris, in turn, indorsed the building and equipment over to Thomas F. Farrell, managing director of ARO.
The Army Corps of Engineers was charged with overseeing part of the design of AEDC and all of its construction. The Tullahoma District was established in 1949 for this purpose.
Following around three years of brick-and-mortar construction, the Engine Test Facility, or ETF, was considered “essentially complete” in July 1953.
“The remainder of the ETF facility is scheduled to be completed and ready for its initial shakedown tests in January 1954,” the November 1953 news release states. “When completed, this test unit will provide three air-tight chambers in which complete turbojet, turboprop and ramjet engines can be operated. The exhaust compressors will pump air out of these chambers to create a rarefied atmosphere in the chamber corresponding to altitudes up to 80,000 feet.
“The inlet air feeding these chambers will be accelerated to supersonic speeds, and the engines will be run in this supersonic airstream to determine their efficiency and operating characteristics.”
ETF began producing its first test data in March 1954.
Prior to their installation at AEDC, the compressors housed in the sound-insulated Exhaust Compressor Building were used in German engine test facilities during World War II.
The use of captured German equipment in a new American test facility was suggested in mid-1945 by Frank Wattendorf, an American scientist who was a member of the Scientific Advisory Group, or SAG. Formed at the behest of Gen. Henry “Hap” Arnold, the SAG was charged with providing recommendations on the direction of U.S. aviation research.
In May 1945, the SAG visited Germany to survey test facilities there and, after their review, Wattendorf documented his findings in a June 1945 report known as the Trans-Atlantic Memo. In his report, Wattendorf not only suggested that study be given to the establishment of a “new Air Forces research and development center” – the first recommendation for a center such as AEDC – but he also wrote captured German equipment should be utilized at the new center.
Present to witness the November 1953 turnover ceremony was Lt. Col. Frank W. Williams, ETF project chief. Williams pushed the button that stopped the equipment at the German jet engine test plant near Munich after World War II. He was subsequently put in charge of the compressor installation project at AEDC, where he pushed the switches to restart the compressors for preliminary testing.
This is the 20th in a series of articles highlighting the history of Arnold Engineering Development Complex during its first 75 years. Additional articles will be published throughout 2026 to commemorate the anniversary of AEDC.