U.S. Air Force Replacing Tail Pipes on B-2 Bomber

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U.S. Air Force Replacing Tail Pipes on B-2 Bomber
On March 6, 2012, U.S. Air Force Tech. Sgt. Jim Gargano, 509th Maintenance Squadron metals technology assistant section chief, at Whiteman AFB, Mo. welds a connector of a B-2 Spirit Bomber tail pipe liner (U.S. Air Force Photo)

The U.S. Air Force is replacing tail pipes on the Northrop Grumman [NOC] B-2 Spirit stealth bomber as a follow-on effort to stopgap work begun a decade ago.

Each of the 20 B-2s stationed at Whiteman AFB, Mo., has four General Electric [GE] F118-GE-100 turbofan engines. The Air Force fielded the first B-2 in 1993.

Air Force Materiel Command’s (AFMC) 424th Supply Chain Management Squadron at Tinker AFB, Okla., began to buy liners and other parts to protect the tail pipe parts about a decade ago and is now looking to replace mid-duct and aft covers for the tailpipes. AFMC also plans for repair of the forward ducts and the B-2’s exhaust gas mixer.

The mid and aft liners are “what wears out at a faster rate than the other components of the [tail pipe] assembly,” AFMC said. “Replacing them was the interim fix to continue to fly the full assemblies and keep them serviceable.”

The B-2’s tail pipes are the original assemblies “and have been overflown,” the command said.

Citing the open solicitation, Northrop Grumman deferred questions on the tail pipes to the Air Force.

“In an effort to do a Full Fleet Replacement, the 424 Supply Chain has sought a Phase III approach to reduce impact to working capital funds,” AFMC said on Oct. 28. “We are currently procuring 50 EA [each] LH [left-hand] & 50 EA RH [right-hand] full assemblies. We already have Phase I on contract that was for 13 EA LH & 13 EA RH that includes a first article. Phase II is in audit with [the] DCAA [Defense Contract Audit Agency] for 15 EA LH & 15 EA RH, Phase III is on its way to DLA [Defense Logistics Agency] contracting for the remainder–23 EA LH & 23 EA RH. Any sub-assemblies purchased from 2011 forward were the ‘get-through’ plan to keep tail pipes on wing until the full assemblies could be bought and delivered.”

The heat-resistant, superalloy Inconel and the high strength-to-weight ratio titanium metal are key components of the tail pipe assemblies.

“The tailpipe assemblies are made from various materials that withstand high temperature engine exhaust gases,” AFMC said. “The prime contractor–Northrop Grumman–has several subcontractors fabricating different subassemblies.  These contractors include General Electric and Barnes Aerospace.  Northrop Grumman is managing the effort and performing the final assembly and testing prior to delivery to the Air Force.”

Barnes Aerospace–a unit of Barnes Group, Inc. [B]–said in April last year that it will build B-2 tailpipe subassemblies at the company’s Ogden, Ut. plant, “which has deep expertise in precision exotic metal forming and complex assemblies.”

“Barnes Aerospace has a long-term relationship with Northrop Grumman on difficult to manufacture, complex products,” the company said.

To help shield the B-2 from detection by surface to air missiles, the aircraft’s exhaust nozzles are mounted on top of the aircraft, and cooling vents reduce the plane’s exhaust gas temperature.

The B-2 first saw combat during Operation Allied Force against Serbia in 1999 and has also seen action in Afghanistan, Iraq and Libya, where it destroyed ISIS camps in 2017.

Northrop Grumman and the Air Force plan to unveil the B-2’s successor–the company’s B-21 Raider–in Palmdale, Calif., on Dec. 2 (Defense Daily, Oct. 20). The B-21 is to have its first flight next year.

The Air Force and Northrop Grumman have said that six of the bombers are under construction in Palmdale, and Sen. Mike Rounds (R-S.D.) said in July after visiting the plant that he was “pleased to report the B-21 is on time and on budget” (Defense Daily, July 22).

Ellsworth AFB, S.D., is to be the first base to receive the B-21 in 2024-25.

The Air Force fiscal 2023 budget request contains the first procurement funding for the B-21–nearly $1.8 billion for the low-rate initial production (LRIP) phase.

Northrop Grumman’s bid for the B-21 included a specific quantity of LRIP aircraft at a fixed-price, Northrop Grumman CEO Kathy Warden has said, noting that while she can’t disclose the number of aircraft, “it’s a small portion of the overall program of record” (Defense Daily, Apr. 28).