Replacing decades-old exhauster motors expected to increase reliability, availability for testing base wide

ARNOLD AIR FORCE BASE, Tenn. – Exhauster motors near the Arnold Engineering Development Complex (AEDC) Engine Test Facility at Arnold Air Force Base are being replaced after being in service since at least 1958.

The motors, referred to as the A and B exhauster motors, have been used to exhaust up to a combined total of 1,100 pounds of air per second during testing.

In the 61-plus years that the motors have been in use, they have supported the testing of numerous aircraft engines, including those used for the B-1 Lancer, B-47 Stratojet, B-52 Stratofortress, C-5 Galaxy, F-15 Eagle, F-16 Fighting Falcon, F-22 Raptor, F-35 Lightning II and U-2, a high-altitude reconnaissance aircraft, as well as cruise missiles and other projects.

“The new 38,000 horsepower motors in A Plant will greatly increase reliability, availability and maintainability to support test cells across Arnold Air Force Base,” said Maj. Michael Knauf, AEDC Aeropropulsion Operations Officer.

Knauf added this is a major maintenance project for AEDC.

“For the B motors, we will be replacing five motors with three, each 10,000 horsepower,” he said. “These will support three of the six compressors in B Plant.”

Combined with the A motor replacement project, this is a $32 million project. In A Plant, four motors will be replaced with two new ones, 38,000 horsepower each.

These exhauster motors not only support engine testing for jet engine cells J-1 and J-2, but also support testing at the J-6 Large Rocket Motor Test Facility, the H2 High Temperature Lab and the Propulsion Wind Tunnel Facility.

“They’re integral to the entire base and each of the Combined Test Forces on the base because they all utilize this exhaust plant,” Knauf said.

Jay Maniscalco, asset manager for the Aeroproulsion Combined Test Force, added that the exhauster motor replacement project is also historically significant for Arnold.

“ETF B was the first plant for the Engine Test Facility, which was completed in May 1954, and a lot of the equipment came over from Germany and the newer motors are still driving these old German compressors,” he said.

One of the B Plant motors originally entered service at the Bayerische Motoren Werkes, or BMW, plant in Munich, Germany in 1942, and was shipped to the United States in 1948 following World War II.  

The new A Plant exhauster motors are also from a manufacturer in Germany, and according to Maniscalco there are no others like them.

“I recently took a trip to visit the company to check out the motors before they were brought here,” he said. “These are two-of-a-kind motors, made specifically for use here at Arnold.”

In addition to the exhauster motors, the equipment used to get these motors up and running is being upgraded.

“All the electrical and controls infrastructure downstream from the switchgear is being replaced,” Maniscalco said. “We are putting all new drives, new controls and interfaces and with those come all new wiring. So the project is really a large undertaking.”

Subcontractors are spearheading the project, but Maniscalco mentioned it’s been a combined effort, with the Test Operations and Sustainment contractor, National Aerospace Solutions, LLC, also playing a notable role.

“The NAS design team helped in designing the new control system for B Plant, and it’s really a team effort with Air Force, contractors and subcontractors all working together to get this done,” he said.

Checkouts of the new exhauster motors are anticipated within the next few months to validate their capabilities.