Suck, squeeze, bang and blow

  • Published
  • By Airman 1st Class Jacob Morgan
  • 436th Airlift Wing Public Affairs
What weighs more than 10,000 pounds, is more than 9 feet in diameter, operates at up to 37,000 horsepower, and was the first of its kind? No, it's not your car.

To find the answer to this question one could always visit Dover Air Force Base, Del.'s Jet Engine Intermediate Maintenance element, or Jet Engine Shop. They would tell you, it's the TF-39 high-bypass jet engine.

The engine's shaft, at full thrust, can spin faster than 10,000 revolutions per minute. The same engine technology is used on United States Navy' vessels as well as in wind tunnels around the world.

"The whole process of the engine could be described as suck, squeeze, bang and blow," said Tech. Sgt. Mark Weisbrod, 436th Maintenance Squadron Jet Engine Intermediate Maintenance section chief.

Air is sucked in, squeezed in a compressor, ignited in the combustion chamber, and blown either through the back of the engine, or to the front to help rotate the titanium fan.

These engines are used on the C-5 A and B model; the B models constitute 78 percent of Dover AFB's 436th Airlift Wing's C-5 inventory.

Jet Engine Shop manages the majority of major repairs to the engines, as well as operating them in the 436th Airlift Wing and 512th Airlift Wing's Engine Test Cell Building.

The shop consists of active-duty, reserve, civil service and contracted members. All members are aerospace propulsion technicians, and there are multiple teams of inter-mixed crews within the shop.

The Jet Engine Shop's job is naturally detail oriented and there is a strict process, which the shop operates within.

If the TF-39 has failed for any reason at Dover AFB the engine is processed through the Jet Engine Shop and put through a standard inspection, just like your car would be, said Sergeant Weisbrod.

After the TF-39 is inspected, the problem is found, and the teardown of the outer frame begins. There are a multitude of tasks the aerospace propulsion technicians perform, including fuel pump issues and oil tank renewal.

"Pretty much the only thing we cannot fix is a full tear down, which could include the combustion chamber," said Sergeant Weisbrod. "We send those out to Kelly Aviation Center in San Antonio, Texas."

Once the task is complete and the problem fixed, the engine is sent to the test cell to check for functionality.

On completion of the test cell, the engine is declared "good-to-go" and boxed up to be placed back on a C-5.

The effectiveness is best measured in the mission efficiency rate of the 9th Airlift Squadron. While deployed to Europe and the Middle East transporting helicopters back and forth for the United States Army, the C-5B's from the 9 AS where more than 94 percent efficient.