Originally posted by Fang
Thanks for that. I'm right in assuming therefore, that with no discernible performance differences between the two engines, this arrangement has more to do with sharing work than anything else?
BAE Systems F-35 Lightning II Crew Escape IPT leader John Thornton said: “We had some significant technical challenges to overcome in the design of the escape system, including providing enhanced neck-load protection during ejection. This is required because the F-35’s state of the art helmet is heavier and has a bigger frontal area to accommodate the visor mounted display. In addition, we also have the challenge of designing a system that can accommodate various sizes of pilot. The F-35 ejection seat is already a design classic. It is the most sophisticated and capable seat in the Western world – and it’s still in development.”
Without improvements, as of 2007 it was estimated that almost 90 percent of the fleet would exceed design limits on engines by 2010. High usage, increased stresses, and more weight than planned threatened to cut life expectancy in half. Significant unknowns exist about extending the life beyond 8,000 hours should that be necessary. If it became necessary to enable the newest F-16 aircraft to reach a 10,000 flying hour life, a program official estimated in 2007 an additional cost of $2.2 billion for structural enhancements. The program office also identified another $3.2 billion in unfunded requirements, including radar upgrades to aircraft capable of suppressing enemy air defenses.
Originally posted by Zaphod58
Probably because even the Super Hornet is a giant sucking POS. It's much better than the original Hornet was, but it still isn't the "great" fighter that people try to make it out to be. They simply stretched a Hornet to get longer legs, and more weapons on it. It still a Hornet, just that it can fly slightly longer missions than the C/D birds could.
Since then, Lockheed has reworked the 270V electrical system to prevent arcing, changed out the integrated power package and incorporated other hardware and software upgrades.....
The failure of a Pratt & Whitney F135 on a test stand in August ended up pacing the return to flight. This led to the decision to "proof test" the flight-test engines to ensure they were not susceptible to high-cycle fatigue failure of the third-stage low-pressure turbine blades.....
And the first short take-off and vertical landing F-35B is to roll off the assembly line on 18 December.
December 7, 2007 (by Eric L. Palmer) - The F-35 Joint Strike Fighter returned to flight today after being grounded since May due to technical difficulties.
The Lightning II's flight began at 1:30 p.m. CST when Chief Test Pilot Jon Beesley executed a military-power (full power without afterburner) takeoff, ran the engine at various power settings and checked flying qualities at 6,000, 17,500 and 20,000 feet, and performed a fuel-dump test at 250 knots. Landing was at 2:15 p.m. CST. Beesley reported that the tests were successful and the jet was a pleasure to fly.
"The Lightning II embodies a long list of advancements that will make it better, smarter and more reliable than anything that’s come before it, and those technologies are extraordinarily mature in this first-ever F-35," Beesley said. "When you project ahead to the F-35s that will be entering the fleet in 2010, you see fighters that benefit from the testing we're doing now – fighters that will set new standards for combat-readiness right out of the box."
December 18th should mark the roll-out of the F-35B, the Short Take-off and Vertical Landing (STOVL) variant of the F-35 Joint Strike Fighter.
Test flight No. 20 was successful, went according to plan and was trouble free, said Dan Crowley, Lockheed Martin executive vice president and F-35 program general manager......
In particular they will be monitoring the electrical-hydraulic controls that operate the aircraft's control surfaces. It was a serious electrical arcing problem in one of the control boxes that caused the emergency on flight No. 19 and led to the plane's grounding while repairs were designed, produced and tested.
Nor are these the only challenging problems facing the F-35 program. The F-35C naval variant's Hamilton Sundstrand power generator was mistakenly designed to only 65% of the required electric output. To accommodate the required increase, it will also be necessary to redesign the gearbox for the standard Pratt & Whitney F135 engine, which will be fitted into the conventional F-35A version as well as the naval F-35C. The contract announced by the US Department of Defense in August 2007 says that this engine update won't be ready for use until the end of 2009, which is almost the beginning of low-rate initial production.