One hundred hours of flight testing shows that the Joint Strike Fighter's F135 engine is good to go, says Pratt & Whitney.
"The engine’s success in flight testing demonstrates the maturity and reliability of the F135 program for armed forces across the globe," the release says, quoting program manager Bill Gostic as saying that "the F135 has met or exceeded all required flight test goals."
I suppose you can't expect the release to mention it, but many people will read or reprint this without recalling that problems with the F135 have, so far, led to some serious delays in the F-35 program. Check Guy Norris in February 2008:
According to information revealed at the December [2007] roll-out of the BF-1 in Fort Worth, Tex., the aircraft was expected to make its first flight from a conventional take-off roll in late May or early June. This was to be followed with a gradual "build-down" to STOVL tests by around the end of 2008.
As we know, we're now looking at those tests starting this summer with a vertical landing by "early fall".
The PW release also states: "By the time the F135 enters operation in 2013, the operating fleet of F119 engines from which it is derived will have logged more than 500,000 flying hours, while the F135 will have logged more than 16,000." First, bookmark that statement - it means that the F-35 test force has, starting today, to average 330 hours a month to reach that target. Second, I thought the Marines were supposed to hit initial operational capability in 2012?
Why all this sunny optimism? "The F135 is the only engine powering the F-35 Lightning II flight test program," the release states. Pratt & Whitney would no doubt like to keep it that way, and the program office has also sought to kill the alternate General Electric/Rolls-Royce F136 engine several times. I suspect that the release is a salvo in that campaign, although we've been reporting for almost two years that the F136 might provide an important performance boost, particularly for the F-35B.
Searching for other 100-hour milestones in flight test - Friday is a good day for a history lesson - I found this from the Time archive.
According to West Coast air gossip, the F-100 is a sweet plane to fly. One test pilot who was flying it for the first time radioed back to earth: "If I were ten years older, this plane would be a great substitute for sex." [? - Ed.] It exceeded the speed of sound on its first test flight. So far it has logged more than 100 hours of flight, and very few bugs have shown up.
One year later, North American chief test pilot George Welch was killed when his F-100 Super Sabre departed controlled flight and broke up.
via Wikipedia - and yes, that is an F-86
Initial reports that Welch's sports coat had exploded were inaccurate - the F-100 had major stability problems. After the vertical stabilizer was drastically enlarged the F-100 went on to a long career as an evil-minded brute with the low-speed handling characteristics of a drunken yak.
Fortunately, today we have simulation and modelling and all that good stuff, so we don't need all that flight testing.
Seriously, what program hasn't had issues arising after the 100-hour mark?
Bill,
If you can get permission from Mr. Gunston, you should post sources of trouble from his book, plane speaking. And, if I maybe so bold, perhaps you should read and post give a dog a bad name from the same book.
YOS,
Jcal1
"This press release contains forward-looking statements concerning the operational prospects for certain engines and, accordingly, the potential for future business opportunities. Actual results may differ materially from those anticipated as a result of certain risks and uncertainties, including but not limited to changes in the USAF's funding related to the F-35 aircraft and F135 engines, changes in government procurement priorities and practices or in the number of aircraft to be built; challenges in the design, development, production and support of technologies; as well as other risks and uncertainties, including but not limited to those detailed from time to time in United Technologies Corporation's Securities and Exchange Commission filings."
I reckon y'all are going to start seeing a lot more of these kinds of 'get out of jail' cards.
Not quite sure how things are in the US of A with your 'Anti Trust Legislation' etc. but 'misleading and deceptive conduct' carries some pretty hefty penalties under the law in countries like the UK and Australia.
Gives a whole new meaning to the various claims about being very comfortable with and supremely confident about, dont you think?
It is known as displaying a total indifference to what is real.
Though, most people know this by another name.
http://home.att.net/~historyzone/Welch2.html
On the other hand, test points are test points, the aircraft has to be properly configured for them to count (the main reason that AA-1 hasn't done that much), and there are lot of Test Bs that can't be done until A1, A2 and A3 have been cleared. It is also still a fact that electronics work one way on a test bench, one way in a 737 and a third way in a hot, cramped, noisy tube.
The trouble with modeling and simulation (and it's just as well we don't say it the other way around because it would cause all kinds of confusion) is that the simulation is only as good as the modeling, and the modeling is often the output of the level of M&S immediately below it, so errors tend to accumulate.
Also, consider that even with the best of tools, the JSF is an extremely complicated, densely packed machine, delivered in three basic versions. Density and complexity were at the root of the weight problems and are a big factor in thermal issues as well. So I think that any assumption that the M&S has sorted out, or will sort out, 83 per cent of the test issues is dangerous.
If the computer models are not V&V-ed with real world data and, moreover, independently, there is a fairly large risk that GIGO will rule and all you have are very expensive video games.
Now some may say this is a bit harsh but, in reality, it is a simplified, cautionary explanation of a somewhat more complicated situation which is the hallmark of this program. This "somewhat more complicted situation" includes considerations of the management, the governance, and overall ethos of the program as much as it includes the physical ground testing as well as all the S&M, of which there has been a bunch.
One example is the approach taken with the STOVL which to many "old and bolds" beggars belief.
There were many risks in this system identified in the early days but, given what has transpired, one can have little confidence they have been properly addressed.
Take just one of these risks - the "thermal management" of the jet during STOVL operations. Now, just take one aspect of this - cooling of the lift fan power transmission clutch/gearbox.
Now much could be written about the do's and don'ts of this aspect of the design and the approach that has been taken, particularly when it comes to being integrated and operated in the aircraft which is already, by design, "thermal management" challenged. The program is now at the point where, as they say, "...the proof of the pudding is in the eating!"
The BIG problem with the approach that has been taken is that the risks earlier identified have now materialised; they have a probability of 1.0 and, therefore, are no longer "risks" but issues, problems, defects and/or deficiences.
Much will be discovered (and, hopefully, learned) from the "hover pit flight testing".