As Honeywell [HON] and RTX‘s [RTX] Collins Aerospace gear up to compete on an upgraded or new Power and Thermal Management System (PTMS) for the F-35 fighter, Collins Aerospace says that it has lab tested hardware for its Enhanced Power and Cooling System (EPACS) offering that will meet the F-35 Joint Program Office’s (JPO) desire to generate 80 Kilowatts to cool and power new weapons and mission systems and that will use less bleed air than the current PTMS.
Honeywell is the incumbent supplier of PTMS for the Lockheed Martin [LMT] F-35,
Air Force Lt. Gen. Michael Schmidt, the head of the F-35 JPO, told the House Armed Services Committee’s tactical air and land forces panel last month that he needs Congress to move beyond a continuing resolution and pass fiscal 2024 defense appropriations legislation to fund the start of a PTMS upgrade or replacement and to continue work on the F135 Engine Core Upgrade (ECU) by RTX’s Pratt & Whitney.
The F-35 JPO is conducting market research on a three-part Thermal Management Unit (TMU) package consisting of PTMS, the Fuel Thermal Management System and the Electrical Power System (EPS).
A TMU Request for Information last month said that the F-35 program wants a 62 Kilowatt to 80 Kilowatt PTMS to handle the F-35’s new systems and upgrades through the life of the program. “To truly understand what it takes to get to those things, I first need Lockheed Martin do a full assessment of the airplane,” Schmidt told the HASC panel last month. “There’s the actual power requirements and then there’s how much can every part of this airplane handle to include the Electrical Power System, the Fuel Thermal Management System–all of those things that we need to get going forward on. There are a number of great suppliers of Power and Thermal Management Systems out there that I want to be in this discussion and will be in this discussion, but I gotta do some really good engineering work first to try to bring all of that together.”
EPACS is to be a new PTMS and one that Collins Aerospace said it began to develop several years ago, as the result of studies by the F-35 program and Lockheed Martin that indicated the need for more PTMS horsepower.
“We’ve demonstrated we can hit 80 Kilowatts across a range of operations relevant to the F-35, and we can do that to bring all that margin, long-term growth capability to the aircraft based on proven technologies in the field,” Matthew Pess, Collins Aerospace’s chief EPACS engineer, said in a Jan. 30 telephone interview. “We brought in a number of our commercial and military pedigree technologies and expect to use less bleed air to provide the 80 Kilowatts than the system takes today.”
Collins Aerospace said at last June’s Paris Air Show that the company had conducted a lab test in Windsor Locks, Conn., of the EPACS (Defense Daily, June 28, 2023).
EPACS includes a Collins Aerospace air cycle system, electric power generator and controller and an auxiliary power unit (APU) by Pratt & Whitney. The F-35 now has Honeywell’s GTS130 APU.
Honeywell’s Torrance, Calif. plant builds the current F-35 PTMS, which supplies main engine start and auxiliary and emergency power needs, in addition to 30 Kilowatts of aircraft cooling.
Matt Milas, president of Honeywell’s defense and space business, has said that an upgraded PTMS, rather than a new system, is what’s needed to field ECU on time. Schmidt told HASC legislators last month that Pratt & Whitney has 600 employees working on ECU so far.
“The way we’re designing the PTMS upgrade you don’t need any additional bleed,” Milas has said. “We’re designing with the current F135 [engine] in mind because we don’t have the ECU data. We found a way to reduce the amount of bleed required by turning on the combustion mode of the APU that’s part of the PTMS system so you can decrease the amount of bleed which reduces the stress on the engine, but also provides a higher level of cooling capability.”
Milas has said that replacing, rather than upgrading, the existing F-35 PTMS, which is integrated in the F-35’s electrical and life support systems, is like “doing heart surgery” and that a new PTMS could cost $3 billion (Defense Daily, Aug. 14).
Asked what Collins Aerospace estimates to be the total EPACS development cost, Pess replied that Collins Aerospace has “provided estimates to Lockheed Martin and to the JPO.”
“We can’t discuss the details of exactly what those numbers are, but we’ve tried to make this as cost efficient as possible by baselining proven technologies and making sure that we’re just putting them together in a way that is usable for the F-35 and provides that capability,” he said on Jan. 30.
Pess said that Collins Aerospace will continue lab testing of EPACS “to validate our models to make sure that when a potential program is launched, we have as much risk burned down as possible and that when we go into doing that integration effort on the program with the Lockheed team, we can understand easily and account for any other changes to the aircraft so that we’re not driving additional risk into the program.”
“There would still need to be quite a bit of work with Lockheed to integrate that onto the platform,” Pess said. “That would be the main goal of an EMD program, but we’re running as representative hardware as we can based on the set of requirements that we have today.”
Collins Aerospace is also a main contractor on the F-35’s Electrical Power System (EPS), which is a project of the former Hamilton Sunstrand, now part of Collins Aerospace. Under EPS, Collins Aerospace builds the main generator for the F135 engine in Rockford, Ill., and the engine’s generator controller, as well as parts of the aircraft’s electrical distribution system. RTX’s Pratt & Whitney builds the F-35’s F135 engine.
Pratt & Whitney said that it
has established firewalls between its F135 ECU and EPACS (Defense Daily, Aug. 16). PTMS is under Lockheed Martin’s F-35 airframe purview, while ECU is under Pratt & Whitney’s responsibility for the F135 engine, and thus Honeywell needs special dispensation from the F-35 JPO to hold talks with Pratt & Whitney, F-35 program and Pratt & Whitney officials have said.
Air Force Frank Kendall has said that the service decided, for cost reasons, to move forward with ECU for the F135 rather than a significantly more costly new engine.