Paywall article from Avaition Week below. Summary is that the JPO are planing to present an F135 to 2035 road map to the US and International partners for approval. The plan essentially is looking at how to increase thrust while reducing fuel burn and is factoring in weight and electrical power requirements for Blk 4 and beyond. P&W already have several options for near term improvements already posted here, Growth Options One and Two. The article suggests that the options are the P&W improvements in the near term and the inclusion of an AETP derived engine in the long term, post 2030. Some challenges remain, such as what a new engine will do to overall fleet sustainment and potentially airframe modifications required to take an AETP adaptive cycle engine.
IMO it appears very likely the P&W F135 GW1 and GW2 options will be funded and, given the performance improvements promised for low modification, provide significant improvements. I have always thought a modified F-35 would come out in the late 2020s anyway, which would be positioned perfectly for an AETP derived engine, and see the last 500 to 700 or so USAF F-35s feature that engine. F135 Upgrades, Reengining Considered In New F-35 Propulsion Road Map
https://aviationweek.com/defense-space/ ... n-road-map
The F-35 Joint Program Office is assembling a proposal for dramatic thrust and fuel-efficiency improvements to the Lockheed Martin fighter’s propulsion system.
The options under review include upgrading the existing Pratt & Whitney F135 turbofan and revisiting earlier studies potentially to reengine the fighter in the longer term with advanced adaptive technology to achieve a step change in range and power.Later this year or in 2021, the Joint Program Office (JPO) will submit the F-35 Propulsion Road Map for 2035, which will propose a recommended timeline for consideration by the three U.S. customers as well as international partners, a JPO spokeswoman confirms to Aviation Week.