Raytheon Technologies‘ [RTX] Pratt & Whitney is gearing up to finish the preliminary design review (PDR) of P&W’s proposed F135 engine core upgrade (ECU) for the Lockheed Martin

[LMT] F-35 and is planning to enter the detailed design phase for the F135 ECU early next year, P&W said at the Paris Air Show on June 19.

“To meet this timeline, the company has more than doubled the F135 ECU team from 200 to 500 people,” P&W said.

As the U.S. Air Force awaits congressional action on the service requested $245 million in fiscal 2024 to begin the F135 ECU, Pratt & Whitney is highlighting not only the goals for improved F135 ECU engine performance and cooling compared to the baseline F135, but also the number of jobs involved (Defense Daily, June 15).

Jill Albertelli, the president of Pratt & Whitney’s military engines business, said this month that the F135 employs 55,000 workers in more than 420 suppliers in the United States.

Pratt & Whitney wants to field the F135 ECU by 2028 to enable weapon and sensor upgrades in Block 4 of the F-35.

“The PDR will focus on demonstrating that the design meets customer requirements with acceptable risk and that the design maturity is sufficient to enter the detailed design phase” P&W said on June 19. “Pratt & Whitney’s F135 ECU preliminary design activities are funded by a $115 million contract awarded in December 2022 and additional funding provided in the FY23 Defense Appropriations bill.”

The Air Force’s fiscal 2024 budget funds F135 ECU and ends the service’s Advanced Engine Transition Program (AETP) to develop a new engine for the F-35 (Defense Daily, March 13).

Air Force Secretary Frank Kendall has said that the service decided on F135 ECU as the more affordable option.

As part of AETP, General Electric proposed its XA100 engine to accommodate the envisioned Block 4 weapons and other upgrades for the Lockheed Martin F-35.

Last October, 48 representatives urged DoD to invest in next generation, adaptive propulsion, such as the XA100, for fighters in a letter co-sponsored by Sens. Rob Portman (R-Ohio) and Sherrod Brown (D-Ohio) and Rep. Brad Wenstrup (R-Ohio).

The F-35 Joint Program Office (JPO) considers the F135 ECU and a new or upgraded Power and Thermal Management System (PTMS) as a single effort (Defense Daily, May 31).

Honeywell [HON] builds the PTMS as a subcontractor to Lockheed Martin. The PTMS uses air pressure from the engine to cool aircraft subsystems and enables main engine start, emergency power, cockpit conditioning, equipment cooling, and some electrical power.

Last month, a Government Accountability Office (GAO) report said that the F135 will need a new or improved PTMS to accommodate future weapons and sensors on the aircraft (Defense Daily, May 30). The question appears to be when.

The GAO report said that the F135’s cooling system “is overtasked, requiring the engine to operate beyond its design parameters” and that “the extra heat is increasing the wear on the engine, reducing its life, and adding $38 billion in maintenance costs.”

While the F-35 JPO has said that it is “very confident we can minimize the $38 billion impact simply with ECU,” the GAO report called into question whether the F135 ECU will provide enough cooling to accommodate Block 4 or whether the F135 ECU will need a new or upgraded PTMS as well to allow Block 4.