I'm a fan of aviation. I have no actual experience with it (outside of riding in the back of helicopters and cursing the pilots and crew chiefs for seeming to try and make me sick or because the damn thing leaks fluid like a new born baby pees its pants)...so articles like this don't help one bit in trying to determine who's right or wrong.
Take these segments of Guy Norris' article in Aviation Week...
The intense battle over powering the F-35 Joint Strike Fighter could be
heading to new levels following test results that show the General
Electric/Rolls-Royce F136 alternate engine has more than 15% thrust
margin against specification, significantly exceeding the power of the
baseline Pratt & Whitney F135.
and then this later on...
“Initial results show we have more than 15% margin at sea level
combat-rated thrust than the specification. That’s significantly beyond
the thrust requirement right out of the chute,” says GE-Rolls. In March
this year, following the first maximum afterburner test of a system
development and demonstration engine, the team quietly expressed
confidence the F136 would exceed the thrust of the baseline F135 by 5%.
Actual thrust achieved in the test remains undisclosed, but it is in
excess of 40,000 lb.
So for an observer and not expert, I'm left with the thought that...ok, the F136 produces 5% more thrust than the F135...but haven't we known that all along?
I'm not an engine guy (there actually is a guy that goes by that name over on F-16.net...maybe I should ask him) but I believe it has to do with engine cores or something like that. But I'm off topic. The point is that this article didn't clear up a thing for me, and it actually muddied the waters. Read it for yourself
here.