Lockheed Martin F-35 Lightning and F-22 'Raptor' : News & Discussion

The Pentagon will have to live with limits on F-35’s supersonic flights

The Navy's and Marine Corps' versions of the F-35 will have restrictions on how long they can fly at supersonic speeds because of a risk of damage to the tail section.



"An issue that risks damage to the F-35’s tail section if the aircraft needs to maintain supersonic speeds is not worth fixing and will instead be addressed by changing the operating parameters :ROFLMAO:, the F-35 Joint Program Office told Defense News in a statement Friday.
The deficiency, first reported by Defense News in 2019, means that at extremely high altitudes, the U.S. Navy’s and Marine Corps’ versions of the F-35 jet can only fly at supersonic speeds for short bursts of time before there is a risk of structural damage and loss of stealth capability.
The problem may make it impossible for the Navy’s F-35C to conduct supersonic intercepts."
 
The Pentagon will have to live with limits on F-35’s supersonic flights

The Navy's and Marine Corps' versions of the F-35 will have restrictions on how long they can fly at supersonic speeds because of a risk of damage to the tail section.



"An issue that risks damage to the F-35’s tail section if the aircraft needs to maintain supersonic speeds is not worth fixing and will instead be addressed by changing the operating parameters :ROFLMAO:, the F-35 Joint Program Office told Defense News in a statement Friday.
The deficiency, first reported by Defense News in 2019, means that at extremely high altitudes, the U.S. Navy’s and Marine Corps’ versions of the F-35 jet can only fly at supersonic speeds for short bursts of time before there is a risk of structural damage and loss of stealth capability.
The problem may make it impossible for the Navy’s F-35C to conduct supersonic intercepts."

They screwed up the jet's performance so badly.

I don't think the US will ever make a one size fits all aircraft for a long time after the F-35.
 
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@vstol Jockey you may be interested

@Picdelamirand-oil do Rafale have such capabilities?
For stealth, the Rafale is LO and the F-35 is VLO, but the Rafale also has active stealth and automatic terrain following which brings its survivability to the same level as that of the F-35, for the rest the only capability described in the video that the Rafale does not have is to be VSTOL. For all the rest the F4.2 Rafale will be capable of it, while for the F-35 everything that is announced in this video is far from working today and it is not certain that it will be when the F4 Rafale will be operational.
 
For stealth, the Rafale is LO and the F-35 is VLO, but the Rafale also has active stealth and automatic terrain following which brings its survivability to the same level as that of the F-35, for the rest the only capability described in the video that the Rafale does not have is to be VSTOL. For all the rest the F4.2 Rafale will be capable of it, while for the F-35 everything that is announced in this video is far from working today and it is not certain that it will be when the F4 Rafale will be operational.
Thank you for the reply, i need to ask wether the f3 version we have ordered have the capabilities like data sharing while in flight, the f35 pilot can see what his peer is seeing. And 360 degree un interrupted view?
And i think rafales active cancelation techniques will not work against AESA radars.
 
Thank you for the reply, i need to ask wether the f3 version we have ordered have the capabilities like data sharing while in flight, the f35 pilot can see what his peer is seeing. And 360 degree un interrupted view?
And i think rafales active cancelation techniques will not work against AESA radars.
On F3 the link used is of the L16 type, but in fact India uses another link with equivalent characteristics and it is this link which equips the Indian Rafale.
With this link the Rafale is already capable of fusing tracks: For example, if a Rafale receives a track by datalink from a radar and has itself a track relative to the same target from Spectra in passive mode where it has an analysis of the radar characteristics of the target and its direction, the Rafale will be able to create a track with its distance (which is calculated thanks to the track received by the link), its direction which is calculated taking into account the two measurements (local and external) and their accuracy and all the technical parameters already analysed.
But the flow rate and the latency of link 16 and equivalent links do not make it possible to make multistatic radar for example and in a general way to make aircraft collaborate to have extended sensors. F4.2 will make this possible even if this possibility will be fully exploited a little later.
As for active stealth, it works against AESA radar and even against AESA LPI radar.
 
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F-35 Block 4 Upgrade is Two Years Late, $1.5 Bn More Expensive: GAO

PARIS --- The cost of developing the F-35’s Block 4 upgrade has grown by $1.5 billion in the past year, and has now reached $12.1 billion despite Joint Program Office attempts to understate it, the Government Accountability Office (GAO) said in its latest annual report on the program released Tuesday.

The GAO also reported that Block 4 development will take two years longer than planned, and that despite promises of improvement the delivery of Block 4 capabilities will not be completed until 2026, instead of 2024.

In addition, “the fielded aircraft, over 500 so far, do not meet the program’s reliability and maintainability goals,” notably because “only about 3,000 of the over 10,000 [Lockheed Martin] manufacturing key processes meet predefined design standards for ensuring product quality.”

“The program is not delivering aircraft at the level of quality expected,” GAO added.

Below are selected quotes from the report.

Block 4 capabilities delayed, cost increases by $1.5 billion

In its May 2019 Block 4 report to Congress, DOD reported that the total cost to develop 66 Block 4 capabilities—both hardware and software—would be $10.6 billion for activities planned from fiscal years 2018 to 2024.

The report also included the F-35 program office estimate of an additional $6.4 billion in fiscal year 2018 through 2024 funding to retrofit aircraft from the baseline F-35 configuration to a full Block 4 configuration.

However, GAO “found that reported Block 4 costs did not include all Block 4 costs…and did not include Block 4 costs the program incurred prior to 2018, or that it will incur after 2024,” as the F-35 program office has chosen to exclude the past and future costs in the Block 4 cost estimate it reported to Congress. This decision understates the true cost of Block 4.

The updated cost estimate reflects that the program office will be fielding Block 4 capabilities into fiscal year 2026. This new schedule adds 2 years analysis of DOD’s updated cost estimate indicates the total cost of Block 4 development grew by $1.5 billion to a total of $12.1 billion for activities in fiscal years 2018 through 2026.

Furthermore, in addition to the Block 4 development costs, the program also estimates it will need another $2.9 billion to develop other capabilities, such as upgrades to ALIS.

“Ultimately, without a complete understanding of Block 4 costs, the program could face additional cost growth, which will be hard to track without a complete cost baseline,” GAO says. “The lack of a complete cost baseline hinders insight and oversight into the program’s costs, plans, and progress to date and going forward.”

Block 4 capabilities delivered late

Lockheed Martin only delivered one Block 4 capability (the auto ground-collision avoidance system) in 2019, instead of eight as planned. According to program officials, the development of the other capabilities is taking longer than planned and, as a result, the program pushed their delivery schedule into 2020.

Development and delivery of the capabilities within the Block 4 effort are complex, and the program does not consider development complete until the products for all elements of the F-35 air system are ready.

The program is also discovering issues during Block 4 testing, causing the testing to take longer than anticipated. According to a DOT&E official, Block 4 software changes caused issues with functionality of F-35 baseline aircraft capabilities that worked before the program installed new Block 4 software onto the aircraft.

The program discovered issues with each new software version during flight testing and has been working to fix these issues in subsequent software updates. Testing and DOD officials stated that the contractor had not performed adequate testing of the software before delivering it to the test fleet as the reason for these issues. Contractor representatives acknowledged these issues and stated that they will conduct additional lab testing for future software releases to avoid such problems going forward.

91% of engines delivered late

In 2019, 91 percent of engines delivered were late. In addition, the average number of quality notifications per engine—production defects indicating a quality issue—has increased by 16 percent in 2019, to 1,090 per delivered engine.

Late parts delivery increase ten-fold

According to program officials, some suppliers for the F-35 struggled to meet increased production demands in 2019 and, as a result, the program witnessed increased rates of late deliveries or parts shortages. In particular, the number of parts delivered late to the airframe contractor, as well as parts shortages, have grown steadily over the past 2 years.

According to the Defense Contract Management Agency:

• Between August 2017 and July 2019, the number of parts delivered late increased from under 2,000 to more than 10,000.

• Between July 2018 and July 2019, the parts shortages per month increased from 875 to over 8,000. According to contractor representatives, roughly 60 percent of parts shortages are attributable to 20 suppliers.

Turkey to continue part production until 2022

“We found that Turkey’s recent suspension from the F-35 program is likely to compound these existing supply chain issues.

“In July 2019, Turkey was suspended from the F-35 program. In particular, the Under Secretary of Defense for Acquisition and Sustainment directed that the F-35 program establish alternative sources and to stop placing orders from Turkish suppliers after March 2020.

“According to an official with that office, Turkish suppliers will provide parts through the end of lot 14 deliveries (scheduled to take place through 2022), in part, to avoid disruptions to aircraft deliveries and additional cost growth from standing up new suppliers.

“The F-35 program office identified that Turkish companies supplied 1,005 parts for the F-35 airframe and engine and some of these parts have been provided by only one supplier.

“As of December 2019, the program has identified new suppliers for all of these parts, but it still needs to bring roughly 15 parts currently produced in Turkey up to the current production rate.”
 
This Lecture By An F-22 Test Pilot On The Raptor's Flight Control System Is Bonkers
Lt. Col. Randy "Laz" Gordon is an accomplished test pilot, engineer, and F-22 Raptor squadron commander who lent his expertise about all things aviation, and especially about the F-22's incredible fly-by-wire flight control system, to students taking MIT's Private Pilot Ground School in 2019. His lecture is astonishingly accessible considering the complexities of the systems and concepts he describes and will give anyone a remarkable appreciation for just how incredible the super-maneuverable Raptor'sflight control system really is.

Gordon covers so much ground in his talk. He talks about the constant tension between low-observability (stealth) and aerodynamics that resulted in the F-22's design, the massive loads the Raptor's powerful flight control system and its huge control surfaces have to instantly counteract, how supersonic flight requires unique flight control concepts, and even how permanent magnetic generators keep power running to the F-22's flight controls just by having the engines windmill.

There is truly an astonishing amount of information in this presentation and it also acts as a great primer for anyone who is new to the concept of fly-by-wire flight control systems.

Some other interesting tidbits include:
  • Raptor pilots make sure their hands are off the flight controls and visible when ground crews are working around a running jet because one touch of the stick could cause the 4,000psi hydraulic system to send a control surface into deflection which can decapitate a ground crewman.
  • Although the F-22's high altitude capabilities, partially a product of its thrust vectoring capabilities, are known, Gordon notes the aircraft flies at altitudes from 60,000-65,000 feet.
  • He describes the pressure-sensitive sidestick control concept, which moves less than a half-inch, very well. The concept was pioneered by the F-16, with the YF-16's sidestick not moving at all before changes were made.
  • The flight controls page on the F-22's multi-function-display is really well described here. The level of automation and simple symbology to describe complex issues is remarkable.
  • The F-22 knows it is about to take off and automatically reconfigures the plane for departure. It does the same upon touchdown.
  • Multiple other automation flight logic modes, in which the flight control system sets to totally different parameters, exist. This is not uncommon on other fly-by-wire aircraft, like airliners, but the F-22's huge flight envelope makes them far more pronounced.
  • There is a mode for aerial refueling to give the jet the best fine handling behind the tanker.
  • In aerial combat mode, you put pressure on the stick and it locks in a G-rate for a turn and stays there even if you take your hand off the stick.
  • When landing, it goes into a pitch command mode, where the pilot simply directs the pitch of the aircraft and it stays there.
  • A large number of limiters are used to make sure the jet is not capable of being structurally overloaded and it even automatically unloads individual parts of the aircraft during certain maneuvers by using flight control surfaces non-traditionally.
  • When an F-22 drops a weapon, namely a 1,000lb JDAM, fuel automatically sloshes forward to maintain center of gravity. There is no fuel panel on the jet to command this, it is all part of the control logic.
Check out the whole video for yourself below:




Although it is not formally talked about in the presentation, as we have discussed in the past, low-observability is also factored into flight control systems on stealthy aircraft. This would be yet another layer to the F-22's flight control programming.
 
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Lightning Rods Protect F-35 Lightnings From Lightning At Exercise Northern Lightning
In what can only be described as the height of irony, personnel at Volk Field in Wisconsin have erected lightning rods to protect F-35A Joint Strike Fighters, also known by their official nickname Lightning II, from, well, lightning. On top of all that, this is taking place during a major joint exercise called Northern Lightning.

This year's iteration of Northern Lightning kicked off on Aug. 10 and is set to run through the end of this week. The F-35As from Vermont's 158th Fighter Wing's 134th Fighter Squadron, the first Air National Guard unit to receive the type, are not the only aircraft taking part. Air National Guard F-16C/D Vipers, as well as F-22 Raptors and T-38 Talons from the Air Force's active component, U.S. Navy F/A-18E/F Super Hornets, and L-139E aggressors from private contractor Draken International, are among the main players participating in the exercise. You can read more about Northern Lightning in this past War Zone piece.

The stunning image of five F-35s sitting underneath three lightning rods, seen at the top of this story and in full below, was taken on Aug. 11 "after a day of flying training," according to the caption. The lightning rods appear to be versions of LBA Technology, Inc's portable PLP-38-MOB model, which the Marine Corps also purchased to shield their F-35Bs from lightning strikes at deployed locations in 2018, which you can read about in more detail in this past War Zone piece.

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Air National Guard

The core issue that requires the use of the lightning rods at all is the F-35's main fuel tank and the rest of the aircraft's fuel system. Unless the interior of the tank and the associated fuel lines are kept "inert," there is a well-established risk that residual fuel vapors, as well as oxygen, could build up inside. If the plane is not "inerted" properly, a lightning strike could potentially lead to a major fire or even a catastrophic explosion. There is also a risk that lightning strikes might cause damage to the components of the already much-maligned Autonomic Logistics Information System (ALIS), which the Air Force is in the process of phasing out, in the jets.

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LBA Technology
An LBA PLP-38-MOB lightning rod in its deployed configuration.

Unlike a metal-skinned aircraft, the F-35's composite material structure also "does not provide inherent passive lightning protection," the Marine Corps explained when buying its lighting rods two years ago. "The lightning rods being requested are needed for deploying aircraft to any expeditionary airfield in support of combat operations or training exercises that do not support all lightning protection requirements."

The F-35s do feature Onboard Inert Gas Generation Systems (OBIGGS) that are designed to pump nitrogen-enriched air into the fuel system to prevent the buildup of these other dangerous gases. However, the reliability of this system was recently called into question after the discovery of damage to tubes that connect the OBIGGS to the main fuel tank earlier this year, which Bloomberg was first to report.

Lockheed Martin halted deliveries of F-35As to the Air Force for much of June after the issue first appeared, but subsequently determined that "it appears this anomaly is occurring in the field after aircraft delivery," according to Defense News. The F-35 Joint Program Office subsequently recommended that units institute a flight restriction that prohibited A models from operating within 25 miles of lightning or thunderstorms.

It's unclear if this has been rescinded since then or if it also applied to the short and vertical takeoff and landing capable F-35Bs that the U.S. Marine Corps operates or the carrier-capable F-35Cs that the U.S. Navy flies. We do know that Marine F-35Bs are regularly seen with the rods in place when parked in different locales.

Even when it's working properly, there have been questions in the past about the OBIGGS overall efficacy.

“The aircraft does not maintain residual inerting after flight for the required interval of 12 hours, which is a lightning protection requirement,” the Office of the Director of Operational Test and Evaluation had warned back in 2015 specifically with regards to the F-35B variant. “If the residual inerting cannot be improved, aircraft maintainers will be required to purge fuel tanks with external nitrogen more frequently or alternative lightning protection strategies (e.g., lightning-protected shelters), will have to be adopted.”

Regardless, it's obvious from the lightning rods at Volk Field is that "alternative lightning protection strategies" are still very much in use to help prevent lightning from blowing up the Lightnings when they're out on the tarmac.
 
is actual radar on F 35 GaN based ?

Ok we have all seen this pic of AN/APG 81 AESA.
884px-AN-APG-81_Antenna,_2005_-_National_Electronics_Museum_-_DSC00393 (1).jpeg

f35-APG81-radar2.jpg

Those are GaAs based module.

While if you look at the radar on latest production model they look somewhat transparent crystal like.

f35-APG81-radar.jpg


GaN is a transparent crystal like material if anybody don't know.

Crystal-GaN (1).jpg


GaNcrystal.jpg


What are the chances that an/apg 81 is GaN based ?
@Bon Plan @randomradio @Picdelamirand-oil
 
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is actual radar on F 35 GaN based ?

Ok we have all seen this pic of AN/APG 81 AESA.
View attachment 17310
View attachment 17308
Those are GaAs based module.

While if you look at the radar on latest production model they look somewhat transparent crystal like.

View attachment 17306

GaN is a transparent crystal like material if anybody don't know.

View attachment 17311

View attachment 17312

What are the chances that an/apg 81 is GaN based ?
@Bon Plan @randomradio @Picdelamirand-oil

In operational F-35's, there's no GaN. In R&D aircraft, it's possible for the aircraft to carry GaN for the F-35's next iteration.

A GaN equipped F-35 is not planned for at least a decade at the current rate of development. So a Block 5 or a Block 10 may see GaN, if not later.

Anyway, what you see in public is not the radar that's actually operational. So there's no point in speculating based on pictures.
 
is actual radar on F 35 GaN based ?

Ok we have all seen this pic of AN/APG 81 AESA.
View attachment 17310
View attachment 17308
Those are GaAs based module.

While if you look at the radar on latest production model they look somewhat transparent crystal like.

View attachment 17306

GaN is a transparent crystal like material if anybody don't know.

View attachment 17311

View attachment 17312

What are the chances that an/apg 81 is GaN based ?
@Bon Plan @randomradio @Picdelamirand-oil
Only sample equipment images are released in public domain. What's operational is only known to those maintaining it, nobody else.
 
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It's known that the US military is already operating at least some GaN AESA radars in other fields, which is more than can be said for others.
 
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It's known that the US military is already operating at least some GaN AESA radars in other fields, which is more than can be said for others.

A lot of countries have already entered the GaN field, even airborne radars like AWACS. A lot of countries already field GaN radars on the ground. India's QRSAM has been deployed at the LAC and has GaN.
 
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