Pratt & Whitney has verified that an unfunded upgrade for the 40,000lb-thrust-class F135 engine could increase the thrust of the Lockheed Martin F-35 by 6-10% and reduce fuel consumption by 5-6%, the company announces on 31 May.

The "growth option 1.0" inserts a package of hardware changes into the F135 power section, consisting of the compressor, combustor and turbine, says Matthew Bromberg, president of P&W Military Engines. By limiting changes to the power module, P&W can deliver the upgrade as a drop-in retrofit and in new production engines for the F-35, he adds.
Ushering the new upgrades into service could take several years. Although P&W has validated the basic technologies in a demonstrator F135 engine, the US joint programme office for the F-35 would have to sponsor a full engineering, manufacturing and development (EMD) programme to prepare the improved engine for production.
If launched now, P&W could begin delivering improved power modules by 2020, Bromberg says.
P&W displayed a demonstrator rig installed in a test cell on the company's sprawling complex in the swamps outside of West Palm Beach, Florida. The demonstrator rig - identified as FX701-01 -- served as a testbed for the new technologies.
Growth option 1.0 becomes available as the US Air Force and Navy researchers pursue even more ambitious upgrades for the F-35 propulsion system.
The advanced engine transition programme (AETP) is expected to develop a new core featuring propulsion technology that "adapts" depending on whether the aircraft is accelerating or cruising. To save fuel, the engine in cruise mode opens a third stream of airflow, which bypasses the core to produce thrust most efficiently.
P&W is developing the XA101 adaptive turbofan engine. GE Aviation is working on the XA102 engine. Both designs are being prepared to possibly replace the F135 and power future combat aircraft.