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F-22 / F-35 5th Generation jets | News & Discussions.

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star of david on the f35

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“The F-35 recently deployed from Hill to Mountain Home where crews, maintenance, and support personnel conducted a number of missions.” Chase said, “During that deployment, crews attained a 100 percent sortie generation rate with 88 of 88 planned sorties and a 94 percent hit rate with 15 of 16 bombs on target. These numbers provide a positive indication of where we are when it comes to stability and component performance.” Through these flights the F-35s were challenged by F-15E aggressors, but the F-35s managed to complete all their missions with zero losses. The missions included Offensive Counter-Air (OCA), Air Interdiction (AI), Suppression of Enemy Air Defense (SEAD), Defensive Counter-Air (DCA) and Close Air Support (CAS).

http://defense-update.com/20160622_f35_ioc.html

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http://www.nellis.af.mil/News/tabid/6431/Article/808248/10-questions-on-the-f-35a-lightning-ii.aspx


Haters gonna hate :jester:
 
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Measuring Stealth Technology's Performance
Aviation Week & Space Technology
Dan Katz
Tue, 2016-06-28 04:00
How low-observable technology enhances aircraft survivability

For the non-U.S. nations buying the Joint Strike Fighter, Lockheed Martin’s F-35 will be their first experience operating stealth aircraft. Since development of the aircraft began 15 years ago, radar technology has advanced and debate over the value of stealth has escalated. But several nations have now selected the F-35 in open competitions, citing in part the combat capability enabled by low observability. As the F-35 debuts at air shows outside the U.S., Aviation Week reexamines the fundamentals of stealth and whether it provides an advantage over the latest adversary radars.

Stealth Basics

Stealth is the science of reducing an object’s detectability to radar. The goal is to minimize the electromagnetic energy reflected back to a radar so it cannot distinguish the return from the signals created by environmental clutter and noise of its internal electronics.

The metric of detectability is called radar cross-section (RCS), which normalizes the reflectivity of targets by comparing them to metal spheres. Human beings have an RCS of about 1m2— they return as much radar energy as a sphere with a geometric cross-section of 1 m2. Since RCSs vary by orders of magnitude, it also is common to use the logarithmic unit “decibel square meters” (dBsm), in which 100 m2 converts to 20 dBsm and 0.1 m2 to -10 dBsm.

RCS varies with the angle and frequency of the radar signal. The sector of greatest interest is ±45 deg. in azimuth and ±15 deg. in elevation, and the frequency band of greatest concern is X-band (8-12 GHz), where most fire-control radars operate. “All-aspect stealth”—minimizing detectability from any angle—and “broadband stealth”—reducing observability over a broader frequency range—can be achieved with greater cost or engineering tradeoffs.

Stealth technology reduces RCS by shaping an aircraft to “scatter” radar waves away from the emitter and using radar-absorbent material (RAM) to reduce reflections by turning the energy into heat. Traditionally, shaping accounts for 90% of stealth’s RCS reduction and materials 10%.

Shaping starts with a focus on “specular” scattering, in which waves bounce off a structure like billiard balls. Flat surfaces reflect most energy at an angle equal to the incident wave and are therefore preferred and oriented to minimize returns to the radar.

Engine intakes, cockpits, 90-deg. corners and other “multiple-bounce structures” reflect the most incoming energy back to their sources. Right angles are avoided entirely. Cockpit canopies are “metallized” with a few nanometers of gold or indium tin oxide to make them reflect radar energy. Engine fan faces can be shielded from radar illumination by external screens (F-117 and RQ-170), internal blockers (F/A-18E/F) or serpentine-shaped inlets (B-2, F-22 and F-35), all of which incorporate RAM.

Weapons and other stores are carried internally. Missiles, bombs and fuel tanks increase RCS with their pylons, round bodies, cruciform tailfins and sensor apertures. They also create multiple-bounce geometries with the airframes, which can increase RCS.

Edges diffract radar energy in a narrow, fan-like pattern but still at an angle equal to the incoming wave, and wing and tail tips diffract waves in all directions. Both are kept narrow to minimize RCS, and edges are angled away from the direction of the threat.

Fuselage facets, control surfaces, leading and trailing edges, and gaps are oriented to concentrate reflections into a minimum number of angles. This “planform alignment” reduces detectability at every other angle. The surface is then covered with RAM, with special treatments for edges and tips.

When waves strike surfaces at grazing angles, they induce currents that travel until they hit a discontinuity, where they radiate waves and bounce back to radiate again. The longer they travel, the weaker they become, particularly if the surface contains RAM, but any discontinuity—an edge, gap or step in the surface, or a material change—reflects them. Gaps around access panels must be covered with conductive tapes or caulks to bridge any electromagnetic discontinuities. Access panels and doors that open in flight, such as those for landing gear and weapon bays, have edges angled to reflect traveling waves away from the threat sector, often creating a “sawtooth” appearance.

Estimating RCS

There are formulas to calculate the RCS of simple shapes and computer programs to estimate those of more complex structures, but due to the difficulty in accounting for nonspecular mechanisms, interaction among structures and RAM, it is better to rely on RCSs determined by testing. Those numbers, sometimes cloaked in terminology of objects, have been discussed publicly.

stealth_measuring_perf_003_zpsrtyol6vw.jpg


Conventional aircraft of similar geometries and size tend to have similar RCSs. The Boeing F-15 has a frontal RCS of around 10 m2. The Sukhoi Su-27 RCS is also in the 10-15-m2 range and the Panavia Tornado is likely in this neighborhood as well. The figure is larger if external stores are carried. The initial Boeing F/A-18’s RCS is believed to be in the 10-m2 realm, but F/A-18C/Ds began incorporating RAM in 1989. The smaller Lockheed Martin F-16’s RCS is believed to be around 1-3 m2; the later C model is slightly stealthier than the F-16A, and signatures have also been reduced under Have Glass programs, which include application of RAM.

Later “Generation 4.5” fighters all employ RCS reduction to some extent. The Eurofighter Typhoon program sought to reduce RCS by a factor of four compared to Tornado. The Sukhoi Su-35 claims reduction of 5-6 times over the Su-27. This likely puts the Su-35, along with Dassault Rafale, in the 1-3-m2 range. The F/A-18E/F, which Boeing says employs the most extensive RCS-reduction measures of any nonstealth fighter, is reported at 0.66-1.26 m2.

While low observability is a spectrum and not a binary quality, “stealthy aircraft” usually implies an RCS of less than 1 m2. Russia’s new T-50 PAK FA is believed to be in the 0.1-1-m2 range. Cruise missiles come in at 0.1-0.2 m2. The F-117 was said to have an RCS equal to a small bird (0.01-001 m2). The F-35 RCS is compared to a “golf ball” and the F-22’s to “a marble”; these objects have RCS of 0.0013 m2 and 0.0002 m2, respectively.

Detectability vs. Radar

How does stealth affect survivability? Since radar waves expand spherically going to and returning from targets, the range at which an aircraft can be detected is proportional to the fourthroot of its RCS. Every tenfold reduction decreases detection range by 44%.

The most advanced Russian fire-control radars yet deployed are the Irbis-E on the Su-35 and the ground-based 92N6E Gravestone, part of the formidable S-400 surface-to-air missile (SAM) system. The manufacturers of the Su-35 and S-400 claim good performance against “stealthy” targets, but their own numbers do not substantiate this.

Sukhoi states the Su-35 can detect a 3-m2 target at 400 km (250 mi.). That is a good range against an F-16 or Typhoon, but it means this newest Flanker cannot detect an F-35 until it is within 36 mi., and inside 22 mi. for an F-22. And the U.S. fighters can launch their medium-range AIM-120 AMRAAMs from more than 60 mi. away. Also, that detection range is for a maximum-power, narrow-angle search. In conventional search mode, the detection range is half as much.

Almaz-Antey’s S-400 is feared for many reasons, including its longest-range (380-km) missile, but it cannot fire until its Gravestone radar has a target. According to the manufacturer, Gravestone detects a 4-m2 target at 250 km (155 mi.). Again, good against “reduced RCS” fighters, but the F-35 would not be seen until 21 mi. away and the F-22 13 mi. away. The U.S.’s internally carried Small Diameter Bombs can be dropped from more than 40 mi. away.

Much of the debate over the continued value of stealth has been generated by developments in lower-frequency radars (to be addressed in the next installment of this series), able to detect aircraft optimized for X-band stealth at longer range. But these are search radars that lack the resolution to provide targeting data. The S-400’s 91N6E “Big Bird” search radar can detect 1-m2 targets at 338 km (210 mi.), almost twice the range of the Gravestone, but its batteries cannot launch until the fire-control Gravestone has a target.

These figures are only estimates, but they are based on established formulas and public data from manufacturers and specialist engineers. The numbers convey the continuing advantage of stealth fighters, which can remain undetected until well within weapons range, even against top-end fire-control radars. These numbers suggest stealth remains a strong contributor to survivability against state-of-the-art weapon systems.

===

Remember...That I have been saying for yrs on PDF that the F-16 is the official unofficial crossover line for 5th-gen level low radar observability. This is not made up. Plenty of people all over the world seen it. And now aviationweek pretty much confirmed it.
 
.
Measuring Stealth Technology's Performance
Aviation Week & Space Technology
Dan Katz
Tue, 2016-06-28 04:00
How low-observable technology enhances aircraft survivability

For the non-U.S. nations buying the Joint Strike Fighter, Lockheed Martin’s F-35 will be their first experience operating stealth aircraft. Since development of the aircraft began 15 years ago, radar technology has advanced and debate over the value of stealth has escalated. But several nations have now selected the F-35 in open competitions, citing in part the combat capability enabled by low observability. As the F-35 debuts at air shows outside the U.S., Aviation Week reexamines the fundamentals of stealth and whether it provides an advantage over the latest adversary radars.

Stealth Basics

Stealth is the science of reducing an object’s detectability to radar. The goal is to minimize the electromagnetic energy reflected back to a radar so it cannot distinguish the return from the signals created by environmental clutter and noise of its internal electronics.

The metric of detectability is called radar cross-section (RCS), which normalizes the reflectivity of targets by comparing them to metal spheres. Human beings have an RCS of about 1m2— they return as much radar energy as a sphere with a geometric cross-section of 1 m2. Since RCSs vary by orders of magnitude, it also is common to use the logarithmic unit “decibel square meters” (dBsm), in which 100 m2 converts to 20 dBsm and 0.1 m2 to -10 dBsm.

RCS varies with the angle and frequency of the radar signal. The sector of greatest interest is ±45 deg. in azimuth and ±15 deg. in elevation, and the frequency band of greatest concern is X-band (8-12 GHz), where most fire-control radars operate. “All-aspect stealth”—minimizing detectability from any angle—and “broadband stealth”—reducing observability over a broader frequency range—can be achieved with greater cost or engineering tradeoffs.

Stealth technology reduces RCS by shaping an aircraft to “scatter” radar waves away from the emitter and using radar-absorbent material (RAM) to reduce reflections by turning the energy into heat. Traditionally, shaping accounts for 90% of stealth’s RCS reduction and materials 10%.

Shaping starts with a focus on “specular” scattering, in which waves bounce off a structure like billiard balls. Flat surfaces reflect most energy at an angle equal to the incident wave and are therefore preferred and oriented to minimize returns to the radar.

Engine intakes, cockpits, 90-deg. corners and other “multiple-bounce structures” reflect the most incoming energy back to their sources. Right angles are avoided entirely. Cockpit canopies are “metallized” with a few nanometers of gold or indium tin oxide to make them reflect radar energy. Engine fan faces can be shielded from radar illumination by external screens (F-117 and RQ-170), internal blockers (F/A-18E/F) or serpentine-shaped inlets (B-2, F-22 and F-35), all of which incorporate RAM.

Weapons and other stores are carried internally. Missiles, bombs and fuel tanks increase RCS with their pylons, round bodies, cruciform tailfins and sensor apertures. They also create multiple-bounce geometries with the airframes, which can increase RCS.

Edges diffract radar energy in a narrow, fan-like pattern but still at an angle equal to the incoming wave, and wing and tail tips diffract waves in all directions. Both are kept narrow to minimize RCS, and edges are angled away from the direction of the threat.

Fuselage facets, control surfaces, leading and trailing edges, and gaps are oriented to concentrate reflections into a minimum number of angles. This “planform alignment” reduces detectability at every other angle. The surface is then covered with RAM, with special treatments for edges and tips.

When waves strike surfaces at grazing angles, they induce currents that travel until they hit a discontinuity, where they radiate waves and bounce back to radiate again. The longer they travel, the weaker they become, particularly if the surface contains RAM, but any discontinuity—an edge, gap or step in the surface, or a material change—reflects them. Gaps around access panels must be covered with conductive tapes or caulks to bridge any electromagnetic discontinuities. Access panels and doors that open in flight, such as those for landing gear and weapon bays, have edges angled to reflect traveling waves away from the threat sector, often creating a “sawtooth” appearance.

Estimating RCS

There are formulas to calculate the RCS of simple shapes and computer programs to estimate those of more complex structures, but due to the difficulty in accounting for nonspecular mechanisms, interaction among structures and RAM, it is better to rely on RCSs determined by testing. Those numbers, sometimes cloaked in terminology of objects, have been discussed publicly.

stealth_measuring_perf_003_zpsrtyol6vw.jpg


Conventional aircraft of similar geometries and size tend to have similar RCSs. The Boeing F-15 has a frontal RCS of around 10 m2. The Sukhoi Su-27 RCS is also in the 10-15-m2 range and the Panavia Tornado is likely in this neighborhood as well. The figure is larger if external stores are carried. The initial Boeing F/A-18’s RCS is believed to be in the 10-m2 realm, but F/A-18C/Ds began incorporating RAM in 1989. The smaller Lockheed Martin F-16’s RCS is believed to be around 1-3 m2; the later C model is slightly stealthier than the F-16A, and signatures have also been reduced under Have Glass programs, which include application of RAM.

Later “Generation 4.5” fighters all employ RCS reduction to some extent. The Eurofighter Typhoon program sought to reduce RCS by a factor of four compared to Tornado. The Sukhoi Su-35 claims reduction of 5-6 times over the Su-27. This likely puts the Su-35, along with Dassault Rafale, in the 1-3-m2 range. The F/A-18E/F, which Boeing says employs the most extensive RCS-reduction measures of any nonstealth fighter, is reported at 0.66-1.26 m2.

While low observability is a spectrum and not a binary quality, “stealthy aircraft” usually implies an RCS of less than 1 m2. Russia’s new T-50 PAK FA is believed to be in the 0.1-1-m2 range. Cruise missiles come in at 0.1-0.2 m2. The F-117 was said to have an RCS equal to a small bird (0.01-001 m2). The F-35 RCS is compared to a “golf ball” and the F-22’s to “a marble”; these objects have RCS of 0.0013 m2 and 0.0002 m2, respectively.

Detectability vs. Radar

How does stealth affect survivability? Since radar waves expand spherically going to and returning from targets, the range at which an aircraft can be detected is proportional to the fourthroot of its RCS. Every tenfold reduction decreases detection range by 44%.

The most advanced Russian fire-control radars yet deployed are the Irbis-E on the Su-35 and the ground-based 92N6E Gravestone, part of the formidable S-400 surface-to-air missile (SAM) system. The manufacturers of the Su-35 and S-400 claim good performance against “stealthy” targets, but their own numbers do not substantiate this.

Sukhoi states the Su-35 can detect a 3-m2 target at 400 km (250 mi.). That is a good range against an F-16 or Typhoon, but it means this newest Flanker cannot detect an F-35 until it is within 36 mi., and inside 22 mi. for an F-22. And the U.S. fighters can launch their medium-range AIM-120 AMRAAMs from more than 60 mi. away. Also, that detection range is for a maximum-power, narrow-angle search. In conventional search mode, the detection range is half as much.

Almaz-Antey’s S-400 is feared for many reasons, including its longest-range (380-km) missile, but it cannot fire until its Gravestone radar has a target. According to the manufacturer, Gravestone detects a 4-m2 target at 250 km (155 mi.). Again, good against “reduced RCS” fighters, but the F-35 would not be seen until 21 mi. away and the F-22 13 mi. away. The U.S.’s internally carried Small Diameter Bombs can be dropped from more than 40 mi. away.

Much of the debate over the continued value of stealth has been generated by developments in lower-frequency radars (to be addressed in the next installment of this series), able to detect aircraft optimized for X-band stealth at longer range. But these are search radars that lack the resolution to provide targeting data. The S-400’s 91N6E “Big Bird” search radar can detect 1-m2 targets at 338 km (210 mi.), almost twice the range of the Gravestone, but its batteries cannot launch until the fire-control Gravestone has a target.

These figures are only estimates, but they are based on established formulas and public data from manufacturers and specialist engineers. The numbers convey the continuing advantage of stealth fighters, which can remain undetected until well within weapons range, even against top-end fire-control radars. These numbers suggest stealth remains a strong contributor to survivability against state-of-the-art weapon systems.

===

Remember...That I have been saying for yrs on PDF that the F-16 is the official unofficial crossover line for 5th-gen level low radar observability. This is not made up. Plenty of people all over the world seen it. And now aviationweek pretty much confirmed it.
Unoffical crossover ??
 
. . . .
First-ever: Marine F-35B takes part in Red Flag 16-3

A Marine F-35B pilot, assigned to the 3rd Marine Aircraft Wing, Marine Corps Air Station Yuma, Az., prepares to take off during Red Flag 16-3 at Nellis Air Force Base, Nev., July 12, 2016. Red Flag provides combat training in a degraded and operationally limited environment making the training mission as realistic as possible.

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3 more news about the F-35. :bunny:

1) The Israeli F-35 makes first flight:

CoXhiuyWcAIt8VJ.jpg:large


CoWvHg1WIAAXpk7.jpg:large


CoXhqCVXEAAduUo.jpg


2) Number of F-35 reaches 196 thus they became most numerous 5 gen fighters overpassing the F-22 with 194. F-35 will remain the most numerous 5 gen fighter for good.

3) Finally

USAF completes F-35A modifications required for IOC
  • 18 July, 2016
  • BY: Stephen Trimble
  • Washington DC
The US Air Force now has the minimum number of 12 Lockheed Martin F-35A fighters with completed modifications required before the first squadron can be declared initially capable for operations, service officials announced on 13 July.

Since 2013, the USAF has planned to declare initial operational capability (IOC) with 12-24 F-35As assigned to the 34th Fighter Squadron at Hill AFB, Utah, from 1 August to 31 December this year.

But that timeframe appeared to be threatened with the discovery of a faulty fuel tank last September. In certain flight conditions, USAF testers found that air can enter the siphon fuel tank, potentially causing the tank to over-pressurise and rupture in-flight.

The USAF restricted the delivered F-35A fleet to 3g maneouvres when carrying a fuel load of fuel. Only when more than half of the fuel tank was empty could the F-35A perform manoeuvres up to 7g’s, the maximum allowable for USAF variant with Block 2B software. The Block 3F version scheduled for release next year will allow the F-35A to operate the full flight envelope with manoeuvres up to 9gs.

Workers at the Ogden Air Logistics Center at Hill AFB are installing a modification in the F-35A fleet to prevent air from entering a fuel transfer line. By adding a relief line controlled by a solenoid valve, the siphon tanks can vent the air that could cause an over-pressurisation, according to a 2015 report by the Defense Department’s office of test and evaluation.

The path to declaring IOC for the F-35A is now driven by a requirement to complete training for pilots and maintainers, the USAF says. The aircraft must be able to carry either a mix of two GBU-31 and two GBU-12 bombs or two AIM-120 AMRAAMs, and perform basic close air support, air interdiction and suppression or destruction of air defences.

The US Marine Corps declared IOC with the F-35B variant last July, standing up the VMFA-121 squadron at Yuma MCAS, Arizona. The navy, meanwhile, plans to achieve IOC between August 2018 and February 2019.


https://www.flightglobal.com/news/a...-f-35a-modifications-required-for-ioc-427568/
 
. . . .
How come you can acquire before us, you are not even a partner country..... :cray:

https://en.wikipedia.org/wiki/Lockheed_Martin_F-35_Lightning_II_procurement
Security Cooperative Participants (SCP)
Israel
Main article: Lockheed Martin F-35 Lightning II Israeli procurement
In 2003, Israel signed a formal letter of agreement, worth almost $20 million, to join the System Development and Demonstration (SDD) effort for the F-35 as a "security cooperation participant" (SCP).[191] The Israeli Air Force (IAF) stated in 2006 that the F-35 is a key part of IAF's recapitalization plans, and that Israel intended to buy over 100 F-35A fighters at an estimated cost of over $5 billion to replace their F-16s over time.[192] Israel was reinstated as a partner in the development of the F-35 on 31 July 2006, after Israeli participation was put on hold following the Chinese arms deal crisis.[193] Israel will buy 20 initial examples of the F-35A, with a total of 75 fighters desired.[194]

Singapore
In February 2003, Singapore joined the JSF program's System Design and Development (SDD) Phase, as a Security Co-operation Participant (SCP).[195] Singapore could be buying up to 100 F-35s.[196] In late 2013, Singapore said they were in "no particular hurry" to buy the F-35, and that they were focusing on upgrading their F-16s in the near-term. Singapore has specific interest in acquiring the F-35B STOVL variant due to the use of road bases adjacent to airfields, most shorter than 8,000 ft (2,400 m).[197] The F-35B could also prove useful if the Endurance-class ships were converted to Landing Helicopter Docks.[198]
 
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