Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 24 Aug 2016, 04:56
by spazsinbad
This article here because it concentrates on da gun - it is a long article so some bits can go elsewhere....
Weapons Tester Cites Further F-35 Challenges
23 Aug 2016 Lara Seligman

"The Pentagon’s top weapons tester is once again sounding the alarm over the F-35 Joint Strike Fighter (JSF), warning that significant deficiencies with the aircraft’s gun, challenges integrating the short-range AIM-9X missile and unresolved software bugs could delay fielding of the fighter’s full capability.

On the heels of the U.S. Air Force’s milestone decision to declare the F-35A ready for war, the Defense Department’s director of operational test and evaluation (DOT&E) is raising new concerns about Lockheed Martin’s fifth-generation fighter. In an internal memo to Defense Department leadership last week, DOT&E warned that the jet still has a long way to go before full combat capability and may run out of funds to fix significant performance problems on time if late discoveries delay the end of the program’s development phase.

Before kicking off a final test period that will put the F-35 in its final warfighting configuration through its paces, known as initial operational test and evaluation (IOT&E), the Joint Program Office (JPO) still has a significant amount of development testing to complete and a number of problems to fix, DOT&E tells Aviation Week.

Still, the JPO is confident it will complete the F-35 program on time and budget, JPO Chief Lt. Gen. Christopher Bogdan tells Aviation Week.

“There were absolutely no surprises in the recent memo from the OSD Director of Operational Test and Evaluation,” Bogdan says. “Specific to the memo, the JPO has been and is currently acting on all the recommendations.”

At the top of DOT&E’s list of concerns is the Air Force F-35A’s 25mm Gatling gun, which will be the jet’s primary means of delivering close-air support to soldiers on the battlefield. [FUD & rong] Most recently, May testing revealed the small door that opens when the gun is fired induces yaw, or sideslip, resulting in aiming errors, according to DOT&E spokesman Maj. Roger Cabiness. Software changes may be necessary to fix the problem, he says. [doh]

This news comes late in the game for the gun system, which is scheduled to begin accuracy testing later this year to prepare it for fielding in 2018. These modifications and subsequent testing to ensure the fixes work, as well as additional changes to correct deficiencies found during early tests in 2015, could delay the start of accuracy testing, DOT&E warns. The U.S. Marine Corps F-35B and U.S. Navy F-35C gun pods are even further behind in testing, so new discoveries that could require late fixes are also possible.

Given the ongoing challenges and risk to the start of accuracy testing, the F-35 may not be able to field its gun on time, DOT&E concludes.

Weapons integration, including the main gun pod, is central to the final Block 3F software load, which is meant to give the F-35 its full warfighting capability. Block 3F also will incorporate external weapons like the precision-guided Small Diameter Bomb (SDB 1) and the short-range air-to-air AIM-9X Sidewinder missile.

But the program is discovering integration problems with both SDB 1 and AIM-9X. DOT&E is particularly concerned with December testing of the AIM-9X, which revealed “load exceedances,” or excess stress, on the Navy F-35C variant’s wing structure during landings and certain maneuvers. This will either limit the F-35C’s ability to carry AIM-9X or require a redesign and testing of the supporting wing structure, DOT&E says.

“Planned weapons testing is behind schedule for SDD [the System Development and Demonstration period] due to software and structural discoveries that delayed testing,” Cabiness warns. “Weapons testing is one of several risk areas affecting completion of flight testing and the start of IOT&E.”...

...The JPO is aware of the limitations of 3i, according to a spokesman. Still, Bogdan has lauded the Air Force’s decision to declare IOC on Aug. 2.

“The U.S. Air Force decision to make the 15 F-35As at Hill Air Force Base combat ready sends a simple and powerful message to America’s friends and foes alike—the F-35 can do its mission,” Bogdan said in an Aug. 2 statement...."

Source: http://aviationweek.com/defense/weapons ... challenges

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 24 Aug 2016, 20:44
by SpudmanWP
Anyone have the memo?

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 24 Aug 2016, 21:30
by spazsinbad
'maus92' says on pPrune that it is not available - yet: http://www.pprune.org/military-aviation ... ost9484362
"There isn't one (a link to the memo.) From the reporting, it appears that a memo was written by the director of DOT&E to the services, but has not been made public. The AvWeek story quotes information provided in part by a DOT&E spokesperson; the Bloomberg report implies that they have seen the memo. It probably just a matter of time before the actual document is leaked (that's how it's gone down in the past.)"

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 25 Aug 2016, 01:03
by johnwill
spazsinbad wrote:This article here because it concentrates on da gun - it is a long article so some bits can go elsewhere....
Weapons Tester Cites Further F-35 Challenges
23 Aug 2016 Lara Seligman

But the program is discovering integration problems with both SDB 1 and AIM-9X. DOT&E is particularly concerned with December testing of the AIM-9X, which revealed “load exceedances,” or excess stress, on the Navy F-35C variant’s wing structure during landings and certain maneuvers. This will either limit the F-35C’s ability to carry AIM-9X or require a redesign and testing of the supporting wing structure, DOT&E says.



This kind of crap is simply infuriating to me. Here is some bureaucratic drone, who knows absolutely nothing about aircraft structures, spouting off on a structures problem that was found during flight testing. A load exceedance means the load measured or extrapolated from flight test is larger than the current limit load. It does not mean there is excess stress, whatever that is. The structure is designed and tested to endure at least 150% of limit load without failure. in most cases, there is additional strength above that load, called positive margin. The normal way to increase load capacity is to do additional stress analysis or static test to 150% of a higher limit load. Most of the time, there is no need to redesign anything. This standard engineering practice.

It seems to me DOT&E struggles to find any little thing to warn about, simply to justify their exalted overpaid positions.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 25 Aug 2016, 01:45
by yeswepromise
Gosh, imagine if these guys had to critique the F-117 when it was in development... with NO gun at all and only 2 racks. Jeepers.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 25 Aug 2016, 04:33
by nathan77
None of these issues seem like deal breakers to me.

It's just a matter of patching the flight control software to compensate the yaw when the gun door is open. I don't even see this as being a difficult fix.

When it comes to the AIM-9X on the F-35C; I'm not convinced it's a show-stopper. Many weapons have certain restrictions (such as G limits). And given I can't imagine many mission profiles that need the AIM-9X when you already have AIM-120's, this might be satisfactory. Another option is whether it's possible to move the rails for the AIM-9X away from the wing-tips slightly, reducing the overall wing stress. It might be easier than beefing up the wing structure.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 14 Sep 2016, 20:25
by SpudmanWP
Here is a section from a recent Aug 9th memo

Recent flight testing of the AIM-9X air-to-air missile, which is mounted externally on the
outermost wing stations and is planned to be fielded on all variants, produced load
exceedances during F-35C landings and up-and-away maneuvers that caused buffet. The
program conducted a review of the margins of safety of the wing substructure and
determined that flight limitations for AIM-9X carriage or a redesign of the supporting
wing structure may be needed. The path ahead for AIM-9X carriage on the F-35C in
Block 3F is not known.


The fix will be tested in November.

The Joint Strike Fighter program will begin flight testing a design fix in November aimed at providing greater support for the weight of the AIM-9X air-to-air missile, an issue that was highlighted in a recent memo by the Pentagon's chief weapons tester. On Aug. 9, J. Michael Gilmore, the director of operational test and evaluation, sent a memo to Defense Department leadership titled " Achieving Full Combat Capability with the Joint Strike Fighter (JSF) is at Substantial Risk ."


https://insidedefense.com/daily-news/f- ... design-fix

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 14 Sep 2016, 22:53
by popcorn
Gilmore couldn't be bothered to ask JPO what remedial measures it was taking to address the issue and include it in his memo? That borders on being intellectually dishonest by not providing his audience with information relevant to their understnding of the issue.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 14 Sep 2016, 23:16
by SpudmanWP
Most people don't know and most "reporters" & bloggers seemed to ignore the fact that Gilmore does not "test" anything and is not officially involved with the Development phase of the F-35 at all. Here is the mission statement from the DOT&E website.

The Director, Operational Test & Evaluation (DOT&E) is the principal staff assistant and senior advisor to the Secretary of Defense on operational test and evaluation (OT&E) in the Department of Defense (DoD). DOT&E is responsible for issuing DoD OT&E policy and procedures; reviewing and analyzing the results of OT&E conducted for each major DoD acquisition program; providing independent assessments to SecDef, the Under Secretary of Defense for Acquisition, Technology and Logistics (USD(AT&L)), and Congress; making budgetary and financial recommendations to the SecDef regarding OT&E; and overseeing major DoD acquisition programs to ensure OT&E is adequate to confirm operational effectiveness and suitability of the defense system in combat use.


Note the lack of the word "development"

As far as not putting planed fixes into his memos, the program knew of everything in the memo and was already working on them (hence the November fix test) before any Gilmore memo came out.

I think the JPO is getting tired of Gilmore's constant intrusion into the program given their latest responses:

Lt. Gen. Christopher Bogdan, the chief of the F-35 Joint Program Office (JPO), told Aviation Week that “There were absolutely no surprises in the recent memo from the OSD Director of Operational Test and Evaluation…..Specific to the memo, the JPO has been and is currently acting on all the recommendations.”

JPO spokesman Joe DellaVedova told Bloomberg that “there were absolutely no surprises” in the memo as “all of the issues mentioned are well-known” and being resolved.


I almost expect a STFU from the JPO one of these days.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 15 Sep 2016, 10:16
by mk82
I think this motto would suit Gilmore very well -> a day late and a dollar short :mrgreen:

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 15 Sep 2016, 17:14
by rheonomic
nathan77 wrote:It's just a matter of patching the flight control software to compensate the yaw when the gun door is open. I don't even see this as being a difficult fix.


It's literally just tweaking a couple of gains when the door is open.

Actually, since the F-35 CLAWs use dynamic inversion, I'd think the aero database would model the effects of the open gun door and the existing CLAWs should be able to regulate the sideslip.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 16 Sep 2016, 18:25
by krorvik
Maj. Morten "Dolby" Hanche has posted another article - this time concerning the topic in this thread:

http://nettsteder.regjeringen.no/kampfl ... s-a-pilot/

Some of it is based on previous post, but I liked the last paragraph:

Three weeks back I was part of a four-ship of F-35s. Our mission was to overcome an advanced airborne threat, while locating and destroying an equally advanced surface based air defense system. After neutralizing these threats, we were able to destroy four additional targets. All this prior to receiving the Block 3F capabilities.
 

It seems to me that the pilots are now routinely putting 4th gen systems (not only aircraft) to shame. Or death, as it would be in a hot situation.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 16 Sep 2016, 23:54
by popcorn
Thanks ktovik, what a great read... Dolby rocks!

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 17 Sep 2016, 00:55
by rheonomic
The JSF JPO PR guys should really put out more articles by Lighting drivers like Dolby; I think they'd be a great way to show the program in a more positive light.

(Of course, that won't stop the most vocal minority that think we should be operating a ton of daytime fighters like the P-26 who'll dismiss them as LM shills...because RNoAF officers are clearly agents of the US Military Industrial Complex...)

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 17 Sep 2016, 01:18
by popcorn
yeswepromise wrote:Gosh, imagine if these guys had to critique the F-117 when it was in development... with NO gun at all and only 2 racks. Jeepers.

That's one benefit of being a black program, avoid the media circus. Good for LRSB.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 17 Sep 2016, 01:48
by yeswepromise
popcorn wrote:
yeswepromise wrote:Gosh, imagine if these guys had to critique the F-117 when it was in development... with NO gun at all and only 2 racks. Jeepers.

That's one benefit of being a black program, avoid the media circus. Good for LRSB.



Yes. On the money.
The F-35 is WAY too white world.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 17 Sep 2016, 02:06
by popcorn
yeswepromise wrote:Yes. On the money.
The F-35 is WAY too white world.

Really way too big to hide and foreign partners have their constituencies to answer to as well.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 21 Sep 2016, 13:36
by hornetfinn
krorvik wrote:Maj. Morten "Dolby" Hanche has posted another article - this time concerning the topic in this thread:

http://nettsteder.regjeringen.no/kampfl ... s-a-pilot/

Some of it is based on previous post, but I liked the last paragraph:

Three weeks back I was part of a four-ship of F-35s. Our mission was to overcome an advanced airborne threat, while locating and destroying an equally advanced surface based air defense system. After neutralizing these threats, we were able to destroy four additional targets. All this prior to receiving the Block 3F capabilities.
 

It seems to me that the pilots are now routinely putting 4th gen systems (not only aircraft) to shame. Or death, as it would be in a hot situation.


I really like what Maj. Morten Hanche has done with his articles. He has very good style for writing complex issues in easy to understand way. :D

What critics fail to understand is that where F-35 Block 3i now has a pretty long list of deficiencies in capabilities, almost all other fighter aircraft lack those capabilities alltogether. When you have a lot of capabilities and features, there will be a lot of deficiencies especially during development. It's like complaining about Windows 10 deficiencies when other alternative is using MS DOS....

To me it seems like F-35 actually exceeds all expectations by large margin and will be immensely successful and will likely be very long lived aircraft.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 21 Sep 2016, 15:19
by popcorn
Dolby exudes credibility as a JSF advocate. His accounts parallel positive feedback from the Marines. As more foreign air services take delivery of their jets, additional success stories will be added to the portfolio. The Israelis should be next and could very likely involve real-world combat.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 22 Sep 2016, 07:42
by hornetfinn
Another critical aspect of the F-35 is its minimal radar signature. Just as with the aerodynamic performance, the «stealthiness» of the F-35 is an inherent quality of the airframe itself. There would be no quick-fix to a disappointing signature. So far, my impression is that the F-35 is very difficult to find. We see this every day when training with the F-35; we detect the F-16s flying in the local airspace at vast ranges, compared to when we detect another F-35.


This quote from Dolby Hanche just dawned to me. It shows that F-35 can detect another F-35 using radar but the range is very much shorter than against F-16. Of course this is to be expected, but shows that F-35 actually can detect another 5th gen fighter with radar. It has also been said many times that 4th gen fighters simply haven't been able to detect 5th gen fighters at all with radar. It also validates the statements that F-35 radar signature is very, very low. F-16 has pretty low RCS by 4th gen fighter standards after all.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 22 Sep 2016, 08:47
by vanshilar
hornetfinn wrote:This quote from Dolby Hanche just dawned to me. It shows that F-35 can detect another F-35 using radar but the range is very much shorter than against F-16. Of course this is to be expected, but shows that F-35 actually can detect another 5th gen fighter with radar. It has also been said many times that 4th gen fighters simply haven't been able to detect 5th gen fighters at all with radar. It also validates the statements that F-35 radar signature is very, very low. F-16 has pretty low RCS by 4th gen fighter standards after all.


Well...although the quote was talking about radar, there's also EODAS. He leaves it unspecified whether or not the other F-35 was detected by radar or EODAS.

I thought it should be fairly obvious that any plane can detect any other plane with radar, it's just a matter of how close? In this case, I'd think it's inaccurate to say that a 4th gen fighter can't detect a 5th gen one. I'm sure if you park one 50 feet in front of the other something will pop up on radar. However, it's more that they won't be able to detect it at any operational distance, i.e. they'll be long dead before they detect it.

For me, the biggest evidence that the F-35 is meeting (and probably surpassing) its RCS and IR signature goals is that Gilmore hasn't complained about them (that I'm aware of offhand). They would be the perfect performance characteristics to complain about; he could justifiably keep the exact figures secret and just make vague statements about how they are "deficient" and "have significant problems" and all that without having to give specifics due to their classified nature. That he doesn't, likely means the F-35's RCS and IR signatures are pretty low.

(Unless Gilmore isn't allowed to comment on classified performance parameters? But many of the things he does comment on are things that are not yet publicly revealed and thus somewhat classified, such as the actual range of the plane.)

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 22 Sep 2016, 11:35
by hornetfinn
vanshilar wrote:I thought it should be fairly obvious that any plane can detect any other plane with radar, it's just a matter of how close? In this case, I'd think it's inaccurate to say that a 4th gen fighter can't detect a 5th gen one. I'm sure if you park one 50 feet in front of the other something will pop up on radar.


No, that's not the case. There are two things here that can prevent radar from detecting anything. First is that if target is as close as 50 feet away, the target will not be seen due to it being inside radar minimum range. Radar system which uses the same antenna for transmit and receive can only see targets that are further away than min range as it can't really transmit and receive at the same time. In typical fighter radars the min detection range is usually hunderds of meters and can be several kilometers in certain radar modes.

More important thing is that there is a limit how weak signals can be detected. Signal to noise ratio must be high enough to differentiate a target from noise. 4th gen fighter MSA or PESA radars have quite high noise figures and thus they can not detect targets with very low RCS at all. There is a limit how small (in radar wavelengths) objects radars can see. It might well be that F-35 RCS is low enough that such radars are incapable of detecting it reliably. Basically the noise masks the very low radar return signals from VLO target. AESA radars have much better performance in this regard and can reliably detect targets with much lower RCS.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 22 Sep 2016, 12:20
by barrelnut
Sometimes radar manufacturers release specifications for their radars, like here for Airbus TRS-4D radar:

http://northamerica.airbus-group.com/no ... tions.html

Target detection capability: RCS 0.01 m2.


So they don't promise to be able to detect targets with C-Band RCS lower than that. And this is for very advanced GaN AESA radar.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 22 Sep 2016, 12:31
by sferrin
barrelnut wrote:Sometimes radar manufacturers release specifications for their radars, like here for Airbus TRS-4D radar:

http://northamerica.airbus-group.com/no ... tions.html

Target detection capability: RCS 0.01 m2.


At what range? 5 miles? 20 miles? 100 miles?

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 22 Sep 2016, 12:55
by hornetfinn
sferrin wrote:
barrelnut wrote:Sometimes radar manufacturers release specifications for their radars, like here for Airbus TRS-4D radar:

http://northamerica.airbus-group.com/no ... tions.html

Target detection capability: RCS 0.01 m2.


At what range? 5 miles? 20 miles? 100 miles?


Probably at any range. This sounds like the minimum signal strength limit limit I mentioned earlier. It's likely that targets with smaller RCS than that can not be detected with very high probability. It might be that this system can detect 0.01 m2 target at say 20 km away, but would not regularly detect 0.001 m2 target at any range, although it probably can with some lower probability.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 22 Sep 2016, 18:50
by vanshilar
hornetfinn wrote:No, that's not the case. There are two things here that can prevent radar from detecting anything.


Hmm neat. I knew that radars typically use the same antenna to receive and transmit, but didn't consider that this means there's a non-zero "switchover" time as it goes from radiating energy to receiving energy, and thus minimum detection distance.

Hmm the noise levels for 4th gen fighters are that high? Poor thing. I guess this explains the anecdote that in exercises, F-15 pilots could visually see the F-22, yet were still unable to get a (radar) weapons lock on it to launch missiles.

Re: Weapons Tester Cites Further F-35 Challenges

Unread postPosted: 23 Sep 2016, 06:50
by hornetfinn
vanshilar wrote:Hmm the noise levels for 4th gen fighters are that high? Poor thing. I guess this explains the anecdote that in exercises, F-15 pilots could visually see the F-22, yet were still unable to get a (radar) weapons lock on it to launch missiles.


Noise levels even in best MSA and PESA radars are significantly higher than in modern AESA radars. Besides noise the return signal is also attenuated in the system much more so than in AESA radars. There is also huge difference in AESA radars and that technology is evolving a lot. Early AESA radars had significantly higher noise levels and signal losses than latest systems and GaN technology seems to promise even better performance than latest systems in that regard also (along with much higher power and much wider available bandwidth). AESA equipped F-15 will probably be able to detect F-22 or F-35 with its radar about as well as F-22 can. It will lack sensor fusion, EW/ESM and networking capabilities though and naturally not having stealth means it will be detected by radar at long ranges itself.

Yes, that anecdote is easily explained by that MSA radar limitation. F-22 and F-35 might well be close to invisible against such radars.