Suspended after F-35B crash in Fort Worth [Texas] Last December, deliveries of Pratt & Whitney’s F-135 engines were finally able to resume last month after a patch was developed to fix an issue that could affect flight safety. But that’s not the only good news for the engine manufacturer, a subsidiary of the Raytheon group.
In fact, the F-35 developed by Lockheed-Martin does not currently have all the capabilities listed in its specifications. This will be the case with the so-called Block 4 version, which will have 66 new features that will require a more powerful engine … which has not yet been funded in 2021.
In its Block 4 version, the F-35 will be heavier, which “requires better thermal management and more power,” explained General Eric Fick, then head of the Pentagon’s F-35 program.
One of the solutions considered was the integration of an engine from the AETP program [Adaptive Engine Transition Program] which was launched in 2016 and aimed to develop an adaptive cycle reactor [ACE], more economical and offers “significantly improved” heat management to gain performance. Two manufacturers were notified of a deal, including GE Aviation for the XA100 and Pratt & Whitney for the XA101.
After completing testing of its XA100 in May 2021, GE Aviation supported the idea of integrating it into the F-35 ported to Block 4… Explaining that the “adaptive engine cycle would offer two modes [économie de carburant ou puissance maximale] while the architecture of the three-flow engine would allow the airflow in the engine to be varied and its efficiency to be optimized depending on the type of use. But Pratt & Whiney is apparently dismissing that option to better defend the candidacy of an upgraded F-135 engine likely to offer 11% more range, 10% more thrust, and 50% more efficient thermal management. And it was this solution that won in the end.
Thus, on March 10, Pentagon officials stated that Pratt & Whitney’s proposal to upgrade the F-135 under the “Engine Core Upgrade” program was the “most cost-effective” option, in addition to the assurance that it would work for everyone would work three variants of the F-35 [A – classique; B- à décollage court et à atterrissage vertical; C- navale].
“We couldn’t fund the AETP program,” said Frank Kendall, Secretary of the Air Force. And to add that “the cost of GE’s XA100 [6 milliards de dollars, soit l’équivalent de 70 F-35A] and doubts that it would work for all F-35 variants led to sticking with the F-135.
“We need something affordable that supports all F-35 variants,” he said. However, a priori only the F-35A could have been equipped with an XA100 humidifier. “There has been discussion about whether it might work with the C variant. But with that of the US Marine Corps [F-35B], it would be very, very difficult, if not impossible.” Here’s how Pratt & Whitney argued in 2021…
However, a GE executive had recently assured that a solution had been found to run the XA100 on the F-35B… Apparently, the engine manufacturer deeply resented the Pentagon’s decision, which “failed to take into account rising geopolitical tensions and game-changing capabilities.” that the XA100 can meet by 2028,” said a spokesman for Defense News. In any case, for the American specialist magazine, the election of the Pentagon is a “great victory” for Pratt & Whitney.