LM has reacted to the performance issues following the recent relaxation of some performance specifications.
IN FOCUS: Lockheed claims F-35 kinematics
Their point is that the performance of a tooled-up 4th gen aircraft will be inferior to a clean F35, with internal weapons. Now, if the UK's F35B's are in the strike role, they will be trying to evade using their low-observable advantage. But if they are in carrier defence mode they will have to engage, and ideally BVR. AMRAAM is being cleared for use, so is that what the UK will have to use, unless Meteor can be shrunk to fit? And either will limit your internal weapons load. Or you carry more externally and accept both stealth and performance penalties - which is not the point. So, in defensive mode, might the UK's F35's be out-gunned, even if not out-flown? Less of an issue for the USN who will have other fighter defence options with Super Hornet; but the UK will not; and the USMC may not either if they don't have any USN carriers close by.
Maybe smaller longer range weapons will be developed so stealth can be maintained
and enough missiles carried - but that must be a demanding technical challenge.
So I am not particularly reassured by FM's response. Strikes me as more spin than substance but I hope I am wrong.
LF