TF33 Upgrade

Pratt & Whitney (P&W) is sticking to its longheld belief that instead of the US Air Force replacing the P&W TF33-P-3 engines in its 76 venerable B-52H Stratofortress bombers to keep them in service for several decades to come, the best option would be to provide upgrade packages for their existing engines.

Speaking at P&W’s recent annual media event, held this year at its development, testing and production facility near West Palm Beach, Florida, P&W Military Engines President Matthew Bromberg – once an officer in a US Navy nuclear submarine – said: “We think the best option is to upgrade the TF33 with an enhancement programme.”

According to Bromberg, enhancing the TF33-P-3 would be “very low cost and low risk” compared with other engine-upgrade options under consideration for the B-52H fleet, including re-engining the aircraft with GE Aviation CF34-10 turbofans providing the same 17,000lb (75.6kN) maximum take-off thrust as the TF33-P-3, but offering much lower fuel burn.

Former P&W Military Engines president Bennett Croswell, who retired earlier this year, had argued that all other B-52H engine upgrades would require redesigned nacelles and had said P&W was developing an upgrade package to reduce TF33-P-3 maintenance costs. Croswell never detailed the technological improvements involved, but by saying on May 31 that the package “would change nothing north of the pylon”, Croswell’s successor Bromberg hinted that the upgrades would not involve the TF33-P- 3’s fan but would be concentrated in its highpressure compressor, combustor and high-pressure turbine stages.

Bromberg also revealed that more than 1,000 TF33 engines are still in service and said that since 1961 the TF33 has accumulated 72 million hours of flight time.

At the same event, Robert Leduc, P&W’s president, said that for two reasons the company had invested approximately $130 million on expanding its military-engine production facilities at West Palm Beach.

First was P&W’s decision to concentrate all production of F135 engines for international F-35 customers there.

This was because the US Department of Defense preferred that F135 production for the US armed forces be separated from production for international customers and also because “international [production] is going to get just as big as US [production] eventually and we wanted to size it” adequately, Leduc said.

The second reason for P&W’s considerable West Palm Beach military engine investment is that it expects production of P&W AeroPower’s TJ-150-1 small turbojet engine – which provides 150lb of thrust – for the Raytheon ADM-160 Miniature Air Launch Decoy (MALD) and MALD-J Jammer missiles to grow by 5% to 7% a year, said Leduc. P&W AeroPower is also developing a TJ-150 version to power the UK’s MBDA SPEAR Cap 3 missile.

After Bromberg had said that today P&W Military Engines has more than 6,500 engines in service, with 23 customers worldwide, as well as 11,000 auxiliary power units (including the TJ-150), long-serving P&W executive Leduc made a startling admission.

Before P&W was contracted in the early 2000s to engine all F-35s: “We thought there was no way back for us in military engines in the late 1990s, 2000.” At that point P&W was considering leaving the military engine business altogether, said Leduc, adding: “The lesson is, when you’re in it [on a] legacy [basis], don’t give up. It can come back.”