While many Americans made the most of the warm late August weather by catching a few final rays of summer, Pratt & Whitney used the occasion to indelibly scorch the image and sound of the F135 engine at full throttle into the minds of a select few journalists invited to the company’s test facility in West Palm Beach. Rather than try to describe it myself, I’ll leave it to one of the professional scribes in attendance.
“Stand on the edge of the Everglades with the August sun beating down on your head, the summer humidity wrapping your skin and the thunderous beat of 43,000 pounds of power causing your chest and the very ground beneath you to thrum,” observed Colin Clark of DoD Buzz. “I wagged my jaw a couple of times so the seal on the hearing protection broke and my ears absorbed the awesome roar of the test engine firing about 100 feet away, hung high in the air. That’s what it’s like to experience testing of Pratt & Whitney’s F135 STOVL engine for the Joint Strike Fighter. It was my first military jet engine test and you can take it to the bank that I was impressed with the technology and with the brute power unleashed and then channeled.”
Government certification (known as initial service release) of the STOVL variant F135 engine is expected before the end of the year and will mark a final achievement in a development program that has already logged more than 19,000 hours and irrefutably proven the maturity of the F135 in the process. It will also serve as an emphatic milestone in a noteworthy year that has already included CTOL variant certification, delivery of the final test engines, 10 flawless vertical landings and counting, a smooth transition to production, supersonic flight of the STOVL variant F-35, affordability goals that are being met, and delivery of eight production engines with about a dozen more before the ball drops in Times Square to usher in 2011.
But the West Palm Beach event was more than just a celebration of what’s come before. As Guy Norris wrote in Aerospace Daily & Defense Report, “Pratt & Whitney is upping the ante in the ongoing F-35 Joint Strike Fighter engine war by revealing the F135 has achieved combat-rated thrust 20% higher than the specification” – an accomplishment demonstrated on both test and production engines.
This level exceeds even the wildest claims from GE and Rolls-Royce, whose F136 engine has logged only about 400 test hours, despite a protracted gestation process that dates back to lost propulsion down-select competitions to the F135 for both the Boeing X-32 and Lockheed Martin X-35 JSF finalists.
Norris added, “Nevertheless, [Pratt & Whitney Military Engines President Warren] Boley says even though Pratt has demonstrated measured thrust with the conventional-takeoff-and-landing (CTOL) engine variant well in excess of the F135’s advertised 43,000-lb.-thrust capability, the focus remains on providing a systems-level solution to the F-35 thrust requirement.” In other words, a core that can generate more thrust than the lift fan or nozzle can accommodate will remain an untapped resource for which the customer has not expressed a need.
And because of the F-35’s stealthy characteristics, extra weapons and stores are unlikely to be carried externally and the platform itself will not be prone to the growth seen on fourth generation, non-stealthy F-15s and F-16s. Translation: “F-35 thrust requirements are set at the beginning of the program and are unlikely to change significantly.”
As the lazy, hazy days of summer yield to autumn and intense policy battles on Capitol Hill, images of the F135 exceeding specs and achieving major milestones are anything but a mirage.