Home » Air » F136 Needs New Lug Nut; Testing Again By Xmas

F136 Needs New Lug Nut; Testing Again By Xmas

By Colin Clark Tuesday, November 3rd, 2009 9:38 am
Posted in Air, Policy, Rumors

The second engine for the Joint Strike Fighter needs a fancy lug nut redesigned and should be back up on the test stand by the end of the year, a GE spokesman says.

The program has been dogged by rumors that it faced a potentially significant redesign of its combustor but the real problem lies with a lug that attaches the diffuser to the combustor, GE spokesman Rick Kennedy said Tuesday morning.

“The actual combustor will not have to be redesigned,” he said. The lug in question is about the size of a small fingernail. The company will know in a few days whether it can proceed with a temporary fix or should pursue a permanent redesign of the lug, Kennedy said. He also said the company was not sure whether the problem with the lug lay with its supplier or if it is a design problem: “We don’t know exactly yet. We think it’s a design issue.” The company has not finished its highly detailed failure analysis yet.

Once the lug issue is resolved, GE/Rolls Royce expect to have three engines functioning “early in the new year,” Kennedy said, including the one taken off the test stand in early October after the lug failed.

Kennedy rebuffed claims that the F136 is lagging far behind Pratt & Whitney in its testing program. Critics say GE only has 52 hours of testing and has suffered four failures during SDD while Pratt’s engine had undergone 700 hours of SDD testing with no failures at roughly the same point in the program. “Our SDD test program is different from Pratt’s… We did all this pre-SDD testing,” Kennedy said, while conceding that GE has “not run as many hours of testing as w would like in 2009.”

The engine’s fundamentals are all where the company wants to see them at this point, he said, saying thrust, heat and wear data are all looking good. He said the company has had to go slow at this phase in the program because “you have to put 2,000 sensors on the engine.” Two of the four engine shutdowns occurred after testing sensors got sucked into the engine. One was the problem with bearing clearance that was resolved pretty quickly. And the fourth and most recent failure involved was the lug nut. “They are not design issues with the engine,” he said, adding that reinstalling the 2,000 testing sensors delays testing by weeks.

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	Formula80 November 3rd, 2009 at 6:27 pm Rick is right on. Lets look at the facts here surrounding the alternate engine: not funded at the levels like P&W and has MUCH fewer engines in the program. Besides, things such as this will happen and you want them to happen during the ground testing. Moreover, issues like this when caught early are actually benificial to the entire program. If the alternate engine gets the funding and support it deserves, the USG will have one of the best 5th generation fighter engines ever built. It’s ashame that we still have LorenThompson even commenting on this alternate engine issue. If we all listened to Loren (speak out of both sides of my mouth) Thompson and Steve (I don’t even know what a jet engine is) Schantz we would be behind N. Korea and China in our technology development.
	BBB November 4th, 2009 at 12:09 pm ” … you want them to happen during the ground testing” … really? Actually, you don’t want them to happen at all, and especially not after only a handful of hours on each engine. I don’t know how anyone claims an engine is 70% “done” after 52 hours of cumulative testing, and any statement about wear (or durability) at this point is just plain silly. GE will find MANY more problems and much more expensive problems as they put real time on their engines.
	Formula80 November 4th, 2009 at 12:20 pm BBB…I agree you don’t want them to happen at all. However, lets be real here; we are talking about jet engine testing. These engines use exotic materials, have very tight clearances and they deal with a range of temperatures and velocities. Of course you want failures (if they are to occur) to happen during ground testing so the porper mitigation and/or fix is developed before its released for flight. Like P&W, there will be hardware issues identified early and even later in the Program. However, the test program allows for these findings and the plan to correct them before flight release. Whats being experienced today for both P&W and GE/RR is no different then what we have experienced on past engine testing programs.….history confirms it.
	BBB November 4th, 2009 at 11:31 pm I’ll be blunt. It is inexcusable to have four test engines with a total cumulative run time (on average 12 hours each) that required at least partial disassembly to fix broken hardware (And please don’t tell me how two were “just” sensor issues, as securing instrumentation ought to be a no brainer). I know of know other program that has had this many issues so early in the program and, arguably, they have not even gotten close to the “tough stuff” — LRHC of the envelope and endurance. I, therefore, take issue with the “history confirms it” comment, as I believe the poor F136 experience is unprecedented.
	TRG November 5th, 2009 at 6:22 pm So BBB what department at P&W do you work in ? It’s pretty obvious with your anti-GE bias that you must have a horse in this race.
	Wayne November 5th, 2009 at 9:37 pm You can bet the heat is on GE right now. This program is not a U.S. defense program, it’s a multi-national one. The U.S. has traditionally “bailed out” design issues (think B-1 program) but there is no way the U.S. can bail out a multi-national program that is up and running full steam ahead. Of course they do control the monetary printing presses… Ah-oh.
	VancBob November 5th, 2009 at 9:51 pm There is no hurry to build this new engine. We’ll probably build several hundred J-25’s, do a Quadrennial Review, and make a brilliant deduction that the plane doesn’t fill the bill and thus cancel it at 250 units. And reset the whole process looking for a F-15, 16, F/A-18, F-117, F-22, F-35 replacement airframe.
	GuidoGuacamole November 5th, 2009 at 11:43 pm I think it is meant that IF something like this is going to occur, the event is better to happen during the testing phase instead of during actual use on an aircraft with men in the plane.
	Wasamottau November 6th, 2009 at 12:44 am Who cares what the engine does. GE is in O’bamas pocket and they will win out in the end game regardless what happens. If the facts don’t fit the RFQ, redo the bid.
	junbug November 6th, 2009 at 4:54 pm AMEN TO THAT.
	Formula80 November 6th, 2009 at 5:12 pm BBB. Check early F100 testing. I think you will find severe stalls/stags that caused hardware damage. Also, there were LPT issues. I was the customer during this time frame and I am aware first hand of problems both early and later in the program. The worse issue the customer experienced in the early F100 days was having to remove “serviceable” F100 engines from the F15’s we received only to send them back to McDonnell Douglas so other jets could ferry to the customer. And, don’ t tell me it was caused by vendor strikes…it was the engine groundings and the delays in fixing the root cause. Is this blunt enough?
	Robertro2 November 7th, 2009 at 4:40 pm during the F-14(navy) when they put in the GE engines from the F-16,there was many problems that came up and it took Grumman to tell GE there problems.….it was a good thing the Navy was wise to put 2 engines in a plane,you lose one you can still get home…so now they back to 0ne engine,why.….
	ConcernedCitizen November 9th, 2009 at 12:36 am So TRG, which part of GE Corp do you work for? Let’s get past the propaganda. Key fact is that GE curtailed virtually all F136 testing throughout 2009, while awaiting the 2010 Defense Spending bill to pass. The reason being they could ill afford repeated technical failures to cloud Congressional maneuvering. Last I knew, $0.5B in 2009 for 52 hours of test hardly seems like being on track to save the US Govt money! BTW — All F136 testing windows at AEDC have recently opened up for the (12,000 hr+ CTOL/CV/STOVL flight qualified) PW F135 through the 1Q of 2010; obviously more of a problem than “a lug nut” with the F136. Why don’t we give them another $0.5B to waste in 2010? 70% complete… what a load of B.S.!
	TRG November 9th, 2009 at 10:54 pm ConcernedCitizen, to the uninformed you might sound like you know what you are talking about. If you are so concerned about $0.5B waste why not be concerned about P&W’s $1.9B and growing over-run of their budget. To date P&W has spent in excess of $6B on their derivative engine where as GE has spent less than $2B on a their effort.
	roland November 10th, 2009 at 5:45 am Check the wiring maybe its on wiring and design.
	STG November 10th, 2009 at 2:38 pm Yes, admittedly they are over budget on this program but consider how bad GE is from the get go, $38 million dollars per test hour based on your numbers and the total number of hours they’ve completed so far. Compared to less then $0.5 million dollars per test hour for Pratt’s. GE is a competant aerospace manufacturer and so is Pratt but P&W didn’t have this bad a run. I think the bottom line no matter how you slice it is that we’re in a perfect storm financially here, we as a country don’t have money to waste on these huge program over-expenditures, and this second engine program is an over-expenditure. It’s outside the normal defense spending budget. I’ve got nothing against GE’s engine, it probably is a damn good engine, it’s just not right for right now…
	Charlie November 20th, 2009 at 8:14 am In the 70’s, the F-15 had serious engine problems. At one point, in Germany, every new (just delivered) plane had one engine pulled after it’s ferry flight. The engine was then installed in an older A/C with high time engines. One of the high time engines was then placed in the new A/C. There were no spares in the pipeline, and this practice helped to maintain the required number of servicable A/C. Remember that these F-15s were at a “front line” AFB, and just a few minutes from the iron curtain. We also traced a fair number of engine problems to the engine control unit, and the approved methods of “trimming” the engines in test cells and during on A/C static tests. I got to the point that I could listen to an F-15 as it was flown around the “patch” and tell if the engines were trimmed properly. The next question then was which one of the two needed help. It was so bad at one point that the engine mfrs reps were the only ones allowed to approve ready for flight status, due to warrenty issues and who was to pay for repairs.