F-35 Multirole Joint Strike Fighter

[ADMk2]

Reading through this Flight Global article (Link) which has been discussed here... makes me wonder:

Is it common for the Pentagon or USAF to lower the "performance bar" of aircraft this late? If yes, were the performance bars of the F-22 and F-18E/F lowered, similarly?

Yep. From recollection the F-22A's top speed and range requirements were lowered, as were it's availability and corrosion resistance requirements.

The Super Hornet had acceleration, speed, altitude, range and payload requirements all lowered, due to drag and wing drop issues, as well as it's infamous "cantered" wing pylons... OTOH it did what the USN really wanted at a development cost of about $4.8B (IIRC). It's upgrade path has also turned it into a very fine combat aircraft.

Designing an aircraft is a compromise. Sometimes pushing for that X level of capability, simply isn't worth the cost or the tradeoff you may have to make in other areas to achieve it.

The F-22A is a classic example. It hit it's performance requirements in terms of acceleration, supercruise, maneuver performance and so on, but it's range suffered as a result. It hit it's low observability requirements, but it's maintainenance requirements are consequently huge.

It reached it's capability goals, but it cost a fortune to do so and many of the planned capabilities (advanced datalinks, IRST, "cheek" or "flank" AESA radar arrays etc) had to be canned.

If dropping 8 seconds on the acceleration time, means the F-35A can add back in the 30 odd pounds of self-protection equipment removed during SWAT, such as the PAO shut off valves, dry bay fire supression system and so on, well then I think it's a pretty simple choice to be made.

Does an 8 second reduction in the time it takes an F-35A (under "standard" paper conditions) to accelerate from Mach 0.8 to Mach 1.2 provide the 25% survivability boost, that the USAF - DOE&T says the self-protection equipment does?

I don't know, but I suspect not...

 

[Vivendi]

What I think could potentially be more significant is not things like reduction in transonic acceleration or lower turn rates but rather things like this:

Perhaps in worst shape is the F-35's software. According to the report, even the initial Block 1 software package is not complete, some 20% remains to be delivered and flight tested. An initial version of the more advanced, but still not combat capable, Block 2A software was delivered four months late to flight test. "In eight subsequent versions released to flight test, only a limited portion of the full, planned Block 2A capability (less than 50 percent) became available and delivered to production," the report reads. "The program made virtually no progress in the development, integration, and laboratory testing of any software beyond 2B. Block 3i software, required for delivery of Lot 6 aircraft and hosted on an upgraded processor, has lagged in integration and laboratory testing."

This could delay things further, and increase costs in particular for those partners that have very old a/c and urgently need to replace them. Anyway I am crossing my fingers and hoping they will resolve the software issues in the near future.

 

[ADMk2]

What I think could potentially be more significant is not things like reduction in transonic acceleration or lower turn rates but rather things like this:



This could delay things further, and increase costs in particular for those partners that have very old a/c and urgently need to replace them. Anyway I am crossing my fingers and hoping they will resolve the software issues in the near future.

Yep there's no doubt this aircraft still needs a ton of work, but let's not forget SDD is scheduled to be completed in 2017, not next week...

 

[Air Force Brat]

Yep there's no doubt this aircraft still needs a ton of work, but let's not forget SDD is scheduled to be completed in 2017, not next week...

Right, and the fact that the USAF and USMC are standing up operationally coded aircraft, even in limited numbers means that they have confidence that this aircraft is still set to take up the slack incrementally and will be fully integrated into combat ready squadrons as software for each block is upgraded, and aircraft become available. I am dissapointed with the transonic roll-off, and the delaminating horizontal stabs when subjected to AB, I am confident that LockMart is working very diligently to bring this aircraft up to spec, and up to speed, it will have some very unique capabilities once we begin to fully realize its potential, and even today measured against the current threat, this aircraft will put its operators in a dominant position, so best not to get to wiggy about all these issues, they are likely out in the open more than usual just by virtue of having to share the info with partners, and as the old heads remind us all, this is SOP with all NEW aircraft.

 

[colay]

All the technical issues have been identified previously, it's not like they have only come to light. As has been pointed out, such matters are par for the course for,such a massive and technically complex,program. In the words of someone who should know..

"Every issue that we have in view today is very much in the category of normal development for a fighter tactical aircraft," Venlet said in testimony. "Good old-fashioned engineering is going to take care of every one of those." - VADM David Venlet

 

[ADMk2]

All the technical issues have been identified previously, it's not like they have only come to light. As has been pointed out, such matters are par for the course for,such a massive and technically complex,program. In the words of someone who should know..

"Every issue that we have in view today is very much in the category of normal development for a fighter tactical aircraft," Venlet said in testimony. "Good old-fashioned engineering is going to take care of every one of those." - VADM David Venlet

Does anyone else not think it significant that after the last 12 months of testing, the ONLY new issue identified by DOE&T was a minor "green glow" that was interfering somewhat with the HUD in the helmet?

I mean it's not like the program flew the aircraft to it's design altitude ceiling, design top speed, went to it's maximum high angle of attack in testing or began stores separation testing in flight this year with the full range of Block III representative weapons, all without identifying any new issues with the aircraft is it?

Oh, wait...



I remember some of the naysayers, telling us 12 months ago or more, that the F-35 still had the most challenging parts of it's envelope to go. Well now it doesn't, but the old issues have sprung up again as the "big" issues...

Funny that none of them are commenting on that...

 

[John Newman]

Does anyone else not think it significant that after the last 12 months of testing, the ONLY new issue identified by DOE&T was a minor "green glow" that was interfering somewhat with the HUD in the helmet?

I mean it's not like the program flew the aircraft to it's design altitude ceiling, design top speed, went to it's maximum high angle of attack in testing or began stores separation testing in flight this year with the full range of Block III representative weapons, all without identifying any new issues with the aircraft is it?

Oh, wait...



I remember some of the naysayers, telling us 12 months ago or more, that the F-35 still had the most challenging parts of it's envelope to go. Well now it doesn't, but the old issues have sprung up again as the "big" issues...

Funny that none of them are commenting on that...

I always enjoy reading the calm, educated and reasonable responses to the issues facing the F35 here on DT.

As opposed the crap that gets reported in the "popular" media and the responses to that by the uneducated media and general public, but such is defence and defence reporting in the wider community.

Is it fair to say that the development and testing program that the F35 is undergoing is far more indepth and involved that any other major system before it? It seems like it to me.

It's always interesting to read the doom and gloom merchants too, eg the Goon squad from APA, rabbiting on about the various Russian and Chinese 5th Gen programs, I do wonder how much testing those programs will actually have before they are declared "ready for operation" and how ready they will really be?

The only concern I have, when reports like this are released, that Governments, eg, our current Australian Government, will use reports like this as an "excuse" to cut the purchase and go with interim solutions like more F/A18F's.

The general public will swallow up what ever they are told, unfortunately they don't know any better.

I hope I'm wrong, but I have a feeling in my gut, that the excuse used will be tied to what is presented by the popular media as more problems with the F35.

Time will tell, again, hope I'm wrong!

 

[colay]

LM has responded to the unflattering DOT&E report on the F-35 Program. A number of the issues raised have fixes that are either in the process of being implemented or being worked upon.

Lockheed addresses Pentagon F-35 DOT&E report

 

[fretburner]

Yep. From recollection the F-22A's top speed and range requirements were lowered, as were it's availability and corrosion resistance requirements.


Designing an aircraft is a compromise. Sometimes pushing for that X level of capability, simply isn't worth the cost or the tradeoff you may have to make in other areas to achieve it.

I guess it's common practice then. Not sure if this means that this is "okay" though. I mean, aren't we supposed to be learning from past "mistakes"? Or it's just that we do learn, but we create new ones because we created new capabilities that nobody else ever encountered before?

Yep there's no doubt this aircraft still needs a ton of work, but let's not forget SDD is scheduled to be completed in 2017, not next week...

What I'm afraid of is that when the Block 3 software is put on the plane, and you will have new issues come up and extend the development period and flight testing further, therefore, pushing the IOC even further back.

 

[ADMk2]

I guess it's common practice then. Not sure if this means that this is "okay" though. I mean, aren't we supposed to be learning from past "mistakes"? Or it's just that we do learn, but we create new ones because we created new capabilities that nobody else ever encountered before?

One could look at it from the other point of view too. If we aren't encountering developmental difficulties, are we REALLY pushing any technical boundaries and moving beyond we're we already are?

Boeing and Lockheed Martin could easily continue to build incrementally improved Super Hornets, F-15's and F-16's until the cows come home. It wouldn't be cheap because I can't imagine how purchasing and sustaining 2400 odd fighter aircraft could ever be "cheap" but the fact is these aircraft and the entire construct around them, is increasingly being outclassed by more modern systems.

It would be easy just to stick with the status quo as it's seen today, but in 25 years time, does anyone really expect the world's leading air force to be flying aircraft across it's entire FLEET, that were designed 65+ years ago (at that point)?

I think people are forgetting how rapidly those designs are aging. The YF-16 and YF-17 first flew in 1974. The F-15 first flew in 1972...

Something new is needed. If it's not the F-35, then the whole development cycle saga will commence again.

What I'm afraid of is that when the Block 3 software is put on the plane, and you will have new issues come up and extend the development period and flight testing further, therefore, pushing the IOC even further back.

A defined set of capabilities has been set now. If the development pushes out too far, certain capabilities may well be pushed back, but the world isn't as bad as the DOE&T report presents and the world wouldn't end, even if that happened.

Look at their comments on the Super Hornet for instance. If you just accepted the DOE&T report at face value, it seems that most of it's higher end capability (multi-shot AMRAAM capability, APG-79 electronic attack capability, EWSP capability and so on) is mostly missing.

Yet they are performing well on operations today, including against some surface to air capability in Iraq, Afghanistan and Libya, limited though it may be. Fixes are in place for those remaining issues and development of other capabilities (distributed targetting system, advanced mission computer, advanced SATCOM, IRST capability and so on) continue side by side.

These capabilities are continually evolving. If an F-35 can "only" enter service with AMRAAM, AIM-9X and a gun then it will equal what the Rafale and Eurofighter managed...

I think very few people expect such will be the limit of F-35's capability at it's entry to service...

Do remember that most combat aircraft "enter service" without working EW capability, without a working or integrated targetting pod, without most of the weapons they will eventually have and so on.

Yet for the F-35 the sky is falling if it doesn't have all of these capabilities fully operational in 2017. I don't quite "get" that mindset...

 

[Milne Bay]

One could look at it from the other point of view too. If we aren't encountering developmental difficulties, are we REALLY pushing any technical boundaries and moving beyond we're we already are?

Boeing and Lockheed Martin could easily continue to build incrementally improved Super Hornets, F-15's and F-16's until the cows come home. It wouldn't be cheap because I can't imagine how purchasing and sustaining 2400 odd fighter aircraft could ever be "cheap" but the fact is these aircraft and the entire construct around them, is increasingly being outclassed by more modern systems.

It would be easy just to stick with the status quo as it's seen today, but in 25 years time, does anyone really expect the world's leading air force to be flying aircraft across it's entire FLEET, that were designed 65+ years ago (at that point)?

I think people are forgetting how rapidly those designs are aging. The YF-16 and YF-17 first flew in 1974. The F-15 first flew in 1972...

Something new is needed. If it's not the F-35, then the whole development cycle saga will commence again.



A defined set of capabilities has been set now. If the development pushes out too far, certain capabilities may well be pushed back, but the world isn't as bad as the DOE&T report presents and the world wouldn't end, even if that happened.

Look at their comments on the Super Hornet for instance. If you just accepted the DOE&T report at face value, it seems that most of it's higher end capability (multi-shot AMRAAM capability, APG-79 electronic attack capability, EWSP capability and so on) is mostly missing.

Yet they are performing well on operations today, including against some surface to air capability in Iraq, Afghanistan and Libya, limited though it may be. Fixes are in place for those remaining issues and development of other capabilities (distributed targetting system, advanced mission computer, advanced SATCOM, IRST capability and so on) continue side by side.

These capabilities are continually evolving. If an F-35 can "only" enter service with AMRAAM, AIM-9X and a gun then it will equal what the Rafale and Eurofighter managed...

I think very few people expect such will be the limit of F-35's capability at it's entry to service...

Do remember that most combat aircraft "enter service" without working EW capability, without a working or integrated targetting pod, without most of the weapons they will eventually have and so on.

Yet for the F-35 the sky is falling if it doesn't have all of these capabilities fully operational in 2017. I don't quite "get" that mindset...

Well said.
I think that the kind of "mindset" that you are talking about could best be described as bigotry.
Regardless, there is nothing objective about their point of view!

 

[SpudmanWP]

F-35 JSF Testers Report Progress, Problems
By Guy Norris, Graham Warwick

F-35 JSF Testers Report Progress, Problems

It's big and too much to post here in full so more at the JUMP

Here are some of the tidbits

“The DOT&E report offers 10 recommendations. The F-35 Joint Program Office has already taken action on six of the 10 recommendations,” says the JSF program office, noting all of the issues highlighted in the report were known. “Of the remaining recommendations, three involve vulnerability concerns and are being reviewed.”

While the program continues to evaluate fixes for problems already identified, and to test multiple blocks of mission-system software concurrently, it is pushing ahead into new areas of testing. “From a flight-test perspective, there are two priorities this year: complete weapons verification and high alpha [angle of attack],” says Tom Burbage, Lockheed Martin F-35 program integration executive vice president and general manager.

“We are using 18 aircraft to conduct the equivalent of three development flight-test programs and one mission-system program,” says J.D. McFarlan, F-35 test and verification vice president. “We expect it to eventually include 8,000 flights and 60,000 test points. So far we've collected 22,000 of those, so we are around 36% through the test program.”
Across the three variants, there are 12 aircraft in the flight-sciences test fleet. Another four are assigned to mission-systems testing, with two more—Stovl production aircraft BF-17 and -18—about to join and complete the flight-test stable based at Edwards AFB, Calif., and NAS Patuxent River, Md. Together they had logged 4,243 flight hours by Jan. 7, with the Stovl aircraft logging 1,309 of those hours and conducting 381 vertical landings.

Tests to clear the F-35A “clean wing” flight envelope for the Block 2B initial combat capability—to Mach 1.6/700 kt airspeed, 9g maneuvers and 40,000-ft. altitude (see F-35 Capability Plan table)—are wrapping up. The next step will be to clear the envelope with internal weapons-bay doors open, he says. Release of the Block 2B envelope is planned for mid-2015. Expanding the flight envelope to 50,000 ft. for the Block 3F full combat capability is planned for 2016, when development testing is scheduled to finish.

The flight-sciences sortie rate is ahead of plan for the F-35B and C, but behind for the A, says the DOT&E. There are high-speed/high-altitude restrictions on all three variants caused by the tail scorching. New surface coatings have been flown unsuccessfully, so a new skin design will be tested on CTOL aircraft AF-2 early this year, according to the report.

High angle-of-attack testing is underway at Edwards AFB using aircraft AF-4 equipped with a spin-recovery parachute. Where the F-16 is limited to 26 deg. alpha by its fly-by-wire flight-control system, the F-35's limiter is set at 50 deg. and the aircraft has been flown to 73 deg. to ensure there is sufficient pitch authority. “We have to really slow down to get those pitch conditions—100 kt at 40,000 ft.,” says McFarlan. “Pilots are pleased with the ability to get the nose down from high angle of attack.”

The control system is designed to prevent departure from controlled flight at high alpha. In tests now beginning, the prevention feature is turned off, the aircraft forced to depart and the system turned back on to ensure it recovers the aircraft. The ultimate goal is to demonstrate safe recovery from a flat spin, with the chute as a backup. After completing these tests, they will be repeated with the spin chute removed. High-alpha testing on the F-35B will begin this year.

 

[jack412]

Also what isn't said much is that originally on the tin, it said 3:1 LER, then it went to 4:1 LER and now it's said to be 6:1 LER 4 vs 8 red air.
That's a 100% increase in capability

 

[Air Force Brat]

F-35 JSF Testers Report Progress, Problems
By Guy Norris, Graham Warwick

F-35 JSF Testers Report Progress, Problems

It's big and too much to post here in full so more at the JUMP

Here are some of the tidbits

Thanks for those links Colay and Spud, they give us a much greater understanding of the F-35s real world progress as she makes her entry as an operational aircraft in the USAF and Marine Corp. Todays AFM Daily Report informs that the Marines B is temporarily grounded after a fueldraulic line failure on the actuators to the nozzles, those lines and fittings are being inspected on all 25 Marine Corp B models. This grounding does not affect the A or C models, or ground testing of the B, while they sort it out, indeed two Navy C models simultaneously refueled from a KC-130, and the SDB II completed clearance tests in the weapons bay with an AMRAAM 120, clearing the way for further qualifying the SBD II. All these issues and fixes come about as the result of a very open and aggressive developement process, which everyone needs to be reminded is a vast contrast to Sino and Russian efforts to field a fifth gen, which remains largely cloaked in the shadows, with only brief glimpses for PR purposes in those programs. Cheers AFB

 

[SpudmanWP]

2012 F-35 Flight Test at Edwards AFB

Year in Review for the F-35A at Edwards

[nomedia="http://www.youtube.com/watch?v=oFJYQlGZex0"]2012 F-35 Flight Test at Edwards AFB - YouTube[/nomedia]

 

[Air Force Brat]

2012 F-35 Flight Test at Edwards AFB

Year in Review for the F-35A at Edwards

2012 F-35 Flight Test at Edwards AFB - YouTube

Thanks again for posting Spudman, this will give us all an overall sense of the fine flying qualities of the F-35, as the high AOA testing indicates, the F-135 is very well managed in this aircraft, even at extreme AOAs and attitudes, pulled back to idle thrust the 135 did not flame out, and thats one less thing for our single pilot to have to manage. Like the F-22 before it, the F-35 is a set it and forget it kind of bird, you will not break this bird, you will not depart this bird, you will not overtemp or undertemp this bird, it is a very smart airplane, it will take care of you, what that does in terms of warfighting is allow you to fight the airplane, rather than manage it. Your helmet mounted display will illustrate the battlefield, friend and foe, training alongside the F-22s at Tyndale will give the F-35 pilots and maintainers access to the wealth of information on how to employ this aircraft against all comers, and I'm certain that very shortly the F-35 will go head to head with the F-22, when it is operationally conducive to actually allow them to engage, and I might add that all the partners will likely have this opportunity. What this means is on a future battle field, the F-35 team will have met a very, very capable adversary, and will be able to employ their aircraft in a manner that allows them to win, first time every time! Cheers Brat

Todays AFM Daily Report announces from Edwards that AF-1 joins AF-2 in having reached 500 hours in flight testing at Edwards on Jan 23, 2013, along with the announcement that 43% of flight test hours have been met, Congratualations to the Lightning II flight test team at Edwards.

On further reflection, I should add that my comment about the F-35 not overtemping refers to the F-135 powerplant, not the tailfeathers, I actually think that might make an outstanding squadron patch for someone, as well as my now semi authorized ThunderHogge II moniker, she may be heavy, she may be on fire, but she is coming to a Theatre near you, and she will find you and kill you if you're a bad guy, gauranteeed! Cheers to all, Brat

 

[SpudmanWP]

Bad part and not bad design likely cause of the F-35B grounding.

It should be fixed and cleared for flight ops soon.

Manufacturing problem likely caused F-35B engine failure: sources | Reuters

(Reuters) - Pentagon and industry investigators have pinpointed a manufacturing quality problem as the most likely cause of an engine failure that led to the grounding of the Marine Corps version of the Lockheed Martin Corp F-35 fighter jet, sources familiar with the investigation told Reuters.

Pentagon officials are expected to finalize the finding and the proposed fix at a meeting on Monday, said the sources, who were not authorized to speak publicly. They said the F-35B should be able to resume flights as soon as the "nonconforming" parts supplied by a unit of Parker Hannifin Corp are replaced.

The grounding did not affect the Air Force or Navy versions of the radar-evading new fighter since they do not use the same part.

The Pentagon grounded all 25 F-35B jets on January 18 after a propulsion line associated with the B-model's exhaust system failed just before takeoff during a training flight at Eglin Air Force Base in Florida.

The part in question enables actuator movement for the exhaust system associated with the B-model's engine. Instead of traditional hydraulic fluid, it uses fuel as the operating fluid to reduce weight.

An initial inspection discovered a detached propulsion line in the rear part of the engine compartment, and subsequent tests showed the line was not built to specifications by Stratoflex, a unit of Parker Hannifin.

"It wasn't built to specification as it should have been," said one of the sources. "But there's a very small population of the tubes, and the problem should be fixed soon."

Stratoflex is a subcontractor to engine maker Pratt & Whitney, a unit of United Technologies Corp, which builds the engines for the single-engine, single-seat fighter jet along with Britain's Rolls-Royce Plc.

No comment was immediately available from Stratoflex.

The speedy conclusion of the investigation is good news for the F-35 program, which is racing to complete an aggressive schedule of flight tests this year.

The F-35 program has completed about 34 percent of its planned test flight program, but Lockheed is already building production models of the new warplane.

Lockheed is building three different models of the F-35 fighter jet for the U.S. military and eight countries that helped pay for its development: Britain, Canada, Italy, Turkey, Denmark, the Netherlands, Australia and Norway.

The Pentagon plans to buy 2,443 of the warplanes in coming decades, although many analysts believe U.S. budget constraints and deficits will eventually reduce that overall number.

(Reporting by Andrea Shalal-Esa; Editing by Lisa Von Ahn)

 

[RobWilliams]

This'll be one of those things which won't ever really be widely reported and chances are F35 detractors will still be pointing to the "F35B will blow up if the weather gets a bit nasty" headlines even when the F35 gets cleared

Good to see it's a part problem than a specific design flaw, get those birds back in the air.

 

[SpudmanWP]

It's official now (Hat tip to Spaz for posting on F-16.net)

F-35B’s Grounding Traced to Crimped Fluid Line, Pentagon Says Tony Capaccio Monday, January 28, 2013

News Article - Economia e Finanza con Bloomberg - Repubblica.it

"Jan. 28 (Bloomberg) -- An “improperly crimped” fluid line was the probable cause of a propulsion-system leak that led the Pentagon to suspend flight tests of the F-35 fighter’s Marine Corps version, according to the Pentagon.

The investigation “ruled out any design or maintenance issues,” Pentagon spokesman Joe DellaVedova said today in an e- mailed statement. The evidence revealed “a quality discrepancy” resulting in the crimped line, he said...."

________________________

Engineers discover culprit behind F-35B fueldraulic line failure Dave Majumdar 28 Jan 2013

Engineers discover culprit behind F-35B fueldraulic line failure

"...The investigating team found that six other aircraft had the same manufacturing defect. The faulty parts have been returned to F-35 propulsion system prime contractor Pratt & Whitney for replacement. The fueldraulic line is built by Stratoflex. The company, along with Rolls-Royce and Pratt &Whitney, has "instituted corrective actions to improve their quality control processes and ensure part integrity," the JPO says.

The fueldraulic line powers the actuator movement for the F-35B's STOVL vectoring exhaust system. Instead of traditional hydraulic fluid, the system uses fuel as the operating fluid to reduce weight.

NAVAIR and the JPO are currently "developing a return to flight plan which details the removal and inspection requirements of currently installed fueldraulic lines on the 25 F-35B variants affected by the flight suspension." The B-model has been grounded since 18 January

 

[colay]

More good news out of the program. It's also a testament to the growing maturity of the jet that some 100 test flights scheduled in 2013 will not require a chase plane escort.

Program officer visits integrated F-35 testing facility

Program officer visits integrated F-35 testing facility

2/1/2013 - EDWARDS AIR FORCE BASE, Calif. (AFNS) -- Members of the F-35 Integrated Test Force showcased their accomplishments in the developmental test program to the F-35 Lightning II Joint Program executive officer during his visit here Jan. 22...

ITF members made major progress in testing during Bogden's visit. The program executive officer watched the final test mission for all clean-wing flutter, which certified the F-35 is clear of flutter at speeds up to 1.6 Mach and 700 knots with weapon bay doors open or closed.

"This testing has taken years to accomplish and we were very fortunate he was here to see it. This is an important milestone from a capabilities standpoint and what we will deliver to the warfighter," Schwartz said.