Pratt & Whitney, a business unit of RTX, has successfully completed the preliminary design review (PDR) for the F135 Engine Core Upgrade (ECU), confirming that the programme is on track to “meet and exceed the F-35’s future requirements”, according to a press release.
This upgrade aims to enhance engine durability and performance, fully supporting the Block 4 capabilities for all three variants of the F-35 globally.
During the PDR, both Pratt & Whitney and the F-35 Joint Program Office say they reviewed the design changes and propulsion technologies integral to the ECU. These enhancements are expected to restore the engine’s full lifespan and improve performance to support next-generation weapons and sensors.
“Pratt & Whitney is upgrading the F135 engine with technology from multiple development programs to deliver increased capability and performance for the warfighter,” said Chris Johnson, vice president of Pratt & Whitney’s F135 program, quoted in the news release.
“Upgrading the F-35’s propulsion system to ECU is a critical step toward ensuring the F-35 remains the world’s premier air dominance fighter.”
Earlier this year, the U.S. Department of Defense selected the F135 ECU as the sole modernisation solution for the F-35’s propulsion system, citing Pratt & Whitney’s unique experience and technical expertise. The department noted that the company “has the experience, special skills, proprietary technical documentation, software/algorithms, and technical expertise required to furnish the supplies and services,” according to the press release.
To date, Pratt & Whitney has delivered over 1,200 F135 production engines, which have accumulated more than 860,000 engine flight hours. The F135 ECU will be incorporated into new F-35s during production or retrofitted at various F135 depot sustainment facilities worldwide, as stated in the press release.
Erm, so what does it actually mean then ? Is it the 48.000 thrust upgrade ?
Not quite, it goes to some way to deliver the engine that was originally required and fixes some blade fatigue issues. The engine has a dual stream bypass. Meaning one part of the by pass air is later used for reheat, whilst the other part is used for avionics and exhaust cooling.
As the later Blocks of aircraft were delivered the cooling for the avionics requirement had gone above what the engine could normally deliver. So the ECU would make the engine spin faster. This made the engine run hotter for longer. Which also meant some components were using up their life earlier, thereby needing changing sooner than scheduled.
There is also an issue with the F35B’s -600 version of the engine. Some of the protective heat coating was flaking off the power turbine blades and causing microfractures. This meant the engine had to go for maintenance and be stripped down. P&W had designed a new higher performing blade as part of a growth program. This fixed the problem, so was introduced early. The remaining engines without the upgrade including the F35A/C’s -100/400 will be getting this upgrade.
All the improvement through this upgrade program will give around a 10% improvement in thrust and around 6% in fuel efficiency. But as importantly improve the amount of cooling air is available for avionics cooling.
So will the engine upgrades for the B variant ensure it will also be block 4 capable.or are there any other upgrades (hardware or software) needed for the B variant to be block 4 enabled?
Once we have the new engine will it just be a case of waiting (& a long wait) for block 4 to be released to enable the integration of UK weapons.
Interesting question. according to P&W this upgrade will meet both TR3 and Block 4 requirements. But they have expanded on the truth before. I’d take their words with a pinch of salt, until we do have both the upgraded engine in a TR3 or Block 4 airframe to see if they are telling porkies or not!
I am not a fan of the 35 and in particular the B variant we purchased. The engine upgrade is another looming problem I feel. Lockheed are under real pressure fron the US Congress on the 35 across the board. This maybe just more window dressing to appease Congress.
Anybody that wants to see how Congress are thinking a good starting point to current thinking is an article in The Hill. Com dated 7/7/24.
One headline from that article is the cost of operating the 35. $6 Million PA. The last two paragraphs make for difficult reading for any 35 enthusiast or Lockheed.
F135 Engine Core Upgrade is already a mid life upgrade not a full engine replacement to appease Congress and P&W shareholders. The alternative being a more significant improvement, we are told, and a much bigger bill, with some risk too.
At least engines don’t usually have the integration and complexity challenges of avionics like TR-3 and Block 4. So it’s understandable but harsh to judge F135 with the same expectation. Perhaps the Rolls Royce engine upgrade on B-52 is more comparable to F135 than JSF as a whole. .
I can not understand why the super cooling upgrade seems not to be in use with our F35B aircraft. It would answer most of the complaints about the aircrsft and deliver a huge uplift in performance.