Era of Stealth Fighters Begins to Set



photo: Lockheed Martin 
We wrote back in 2009 "Suffice it to say that IR sensor design cycles will certainly - outpace - stealth airframes." 

Indeed, with the advent of Russian/Chinese stealth fighter, stealth bomber, stealth drone, and stealth cruise missile programs it was only a matter of time until Pentagon planners would turn (back) to Infrared Search and Track (IRST) to confront these developments. More on the Russian stealth fighter program (or lack thereof) later. The last US-Navy aircraft that employed a powerful IRST was the Grumman F-14D. The F-14 Tomcat was retired from USN service in 2006.

Now Lockheed Martin's IRST21 is being deployed into US-Navy fleet service on the F/A-18 and reports on the superb performance of the new IRST pods are coming to light. The US AirForce is going to get the Lockheed Martin Legion Pod.' What makes these new IRST so powerful is they claim to have overcome the traditional range-limitation of IRST - clouds and inclement weather.

Neither the IRST21 or Legion pods can detect range-to-target operating alone, so Lockheed Martin networks two pods together to construct a long-wave-infrared binocular (stereoscopic range measurement) weapons track. One aircraft acting as "L" and the other as "R." So aircraft using the pods will be networked and work in pairs.

The implications of all this for the American F-22, F-35, and other stealth programs are obvious. The high flight speed radio-spectrum airfoil (read: the stealth fighter) has effectively lost the race with sensor improvements. A race the stealth fighter could/can never win. This is because a fighter simply flies too fast to mask its thermodynamic energy. At speed, an objects kinetic energy moving through the air (its velocity) is converted to heat energy (and infrared radiation) through compression and friction. And it gets worse for the stealth fighter:

"The Raptor [and F-35] has one [pitot] tube on either side [of its nose]. These air measurement devices are electrically heated to ~ 270 C (520 F) to keep them from icing at altitude. Indeed, they appear as two hot spots on the nose under FLIR (Forward Looking Infrared)."
We are not going to re-explain why this occurring. We wrote extensively about the Achilles' heel of stealth fighters. Heat. This time we will let Dave Majumdar at The National Interest update you:

"How the Navy's New Block III Super Hornet Could Crush China's J-20 or Russia's Su-57"

"As new adversary fifth-generation stealth fighters such as the Russian Sukhoi Su-57 PAK-FA and the Chengdu J-20 emerge from development, the United States Navy is working on developing and fielding new capabilities that will allow naval aviators to defeat the threat.
The key is Boeing’s new F/A-18E/F Block III Super Hornet—and the advanced new technologies incorporated into the jet—combined with the upgraded capabilities of the Boeing/Lockheed Martin Infrared Search and Track (IRST) Block II pod. By upgrading older platforms with new datalinks, massively increased processing power, and new sensors, Boeing and the Navy have found a way to negate the threat to carrier aviation from emerging low observable threat platforms. “IRST—infrared search and track long-range counter-stealth targeting technology,” Dan Gillian, Boeing’s vice president of F/A-18 & EA-18 Programs for Strike, Surveillance and Mobility, told reporters on May 23. “This is filling a gap for the carrier air wing, bringing that sensor back to the carrier air wing in a networked kind of way.”

Boeing is well into the development of the new Block III Super Hornet, Gillian said. The production of the first six new build Block III jets is expected to start in fiscal year 2018 with production transitioning fully onto the new variant in 2019. The fleet should start receiving their first operational Block III aircraft in 2020 and the jet should deploy onboard a carrier by 2022, Gillian said.

Meanwhile, starting in 2022, Boeing will start to upgrade older Block II aircraft into the Block III configuration as part of the Navy’s Service Life Modification program. Eventually, the entire Navy Super Hornet fleet will be brought up to the Block III standard. Altogether, the Navy intends to modify more than 500 Block II Super Hornets into the Block III configuration and build 116 new Block III aircraft by 2024, however, the fleet could be operating a mix of Block II and III aircraft for quite some time into the 2020s given the program’s ambitious schedule. Together with the Lockheed Martin F-35C, the Block III Super Hornet will remain the backbone of the Navy’s frontline strike fighter fleet for decades to come.

The Block III Super Hornet aircraft incorporates a host of new capabilities ranging from an upgraded 9000-hour airframe, new range-extending conformal fuel tanks (~120 nautical mile boost in mission radius), radar cross-section improvements, enhanced satellite communications, to a new advanced cockpit display system. But the two most significant developments are the addition of the Distributed Targeting Processor-Networked (DTP-N) computer—which exponentially increases the Super Hornet’s processing power—and the high-speed, high-bandwidth, high-throughput anti-jam Internet Protocol-based Tactical Targeting Network Technology (TTNT) datalink.

When the power of the DTP-N and TTNT are combined with the IRST Block II sensor, the resulting capability allows for a pair of Block III Super Hornets to engage enemy stealth aircraft from well beyond visual range—far beyond the range of the jets’ Raytheon AN/APG-79 active electronically scanned array (AESA) radar.

As Gillian explained, while the IRST Block II is not part of the Block III program, the advanced processing, datalinks, and sensor-fused display onboard the new Super Hornet variant enable the new capabilities envisioned for the new sensor.  As Bob Kornegay, Boeing’s capture team leader for domestic F/A-18E/F and EA-18G programs, explains, the critical Common Tactical Picture sensor-fused display will be enabled by the Block III aircraft’s powerful high-speed anti-jam TTNT datalink and the sheer computing power of the DTP-N processor, which is needed to run the complex algorithms that make multi-aircraft data-fusion possible.
What makes the new IRST particularly capable is that it operates in the longwave infrared band, which allows the sensor to passively detect and track targets well beyond the range of the APG-79 radar. “It can see a hot airplane,” Kornegay said. “It has much longer range—it is a long wave long-range IRST—so it can see much further than radar can.”

Boeing has taken into account the traditional limitations of infrared sensors, where performance can be severely degraded by inclement weather—particular clouds and atmospheric moisture—when testing the new sensor, Kornegay said. The new IRST is so advanced that it still consistently generates tracks at extended ranges even taking into account inclement weather and other factors. “We’re not assuming a clear day,” Kornegay said.


A single Block III Super Hornet equipped with a Block II IRST would be able to detect and track a low observable enemy aircraft such a J-20 or Su-57 at extended ranges. However, that lone Block III jet would not be able to generate a weapons quality track on that enemy stealth aircraft because an infrared sensor cannot independently generate range data." - Published in the National Interest

- All media found here is for scholarly and research purposes and protected under U.S. Internet ‘Fair Use’ Law -

Comments

  1. Ranging with only one IRST...https://patents.google.com/patent/US5282013

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  2. Boeing is selling its F / A-18E Block III, natural to make promises. But in the operating world the IRST was dropped off at the French Air Force Rafale and the F / A-18E IRST Block I did not meet the requirements. It is a useful but much more limited system than radar, either in FOV or under poor performance in some atmospheric conditions.

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    1. Hi. Using longwave IR and enough signal processing this old IRST issue has been mitigated. Stealth fighters are losing (lost) the race against sensor design, as i predicted. Its effectivally over. On your weather point: "Boeing has taken into account the traditional limitations of infrared sensors, where performance can be severely degraded by inclement weather—particular clouds and atmospheric moisture—when testing the new sensor, Kornegay said. The new IRST is so advanced that it still consistently generates tracks at extended ranges even taking into account inclement weather and other factors. “We’re not assuming a clear day,” Kornegay said."

      - Boresight

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    2. Stealth losing to the IRST? How many fighters were killed by the IRST? 0. The IRST is far from threatening Stealth, it has an operational detection scale of less than 50km. All new hunting projects are stealth. His statement has no reference. The maximum range of IRST depends on weather conditions and a previous location of the target, far from having the same radar efficiency.

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    3. In addition, Stealth fighters also have low observable IR spectrum. It is a common mistake to disregard LO measurements in the IR spectrum. F-35, for example, has the largest by-pass ratio among fighter aircraft, air collectors below the wings that isolate the engine, air manifold over the fuselage that cools the leading edges, serrated exhaust nozzle that mixing the hot gases, petals of the nozzle with small holes and with air between them and fuselage with a painting with low emissivity in the IR of long waves.

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    4. All that engineering cost/complexity to reduce F-35 longwave IR is negated by its two electrically heated pitot tubes on either side the the chin. Its sad to watch all the engineering effort but into stealth fighters. "The Raptor (and F-35) has one tube on either side. These air measurement devices are electrically heated to ~ 270 C (520 F) to keep them from icing at altitude. Indeed, they appear as two hot spots on the nose under FLIR (Forward Looking Infrared)"

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    5. Myth, pitot tubes have a very small area, the IR signature is proportional to the area of ​​the emitter, its size is irrelevant near the exhaust nozzles and the fuselage.

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    6. The pitot tube can be much hotter than any part, but its small area delivers a much smaller IR emission. It is the basic rule of the IR emitter.

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    7. Link with the formula of the intensity of the IR radiation https://drive.google.com/file/d/1tO9kQAGIH5RQXLTHZM5MqfkSa5hIgcHG/view?usp=drivesdk

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    8. New IRST are so sensitive they can detect heating of missile nosecone. Skyward-G can see objects flying as flow as 300 knots regardless of aspect. Modern IRST will see a heated pitot tube no problem. please see the F-22 pitot tube hot spots here:
      https://theboresight.blogspot.com/2011/07/forward-looking-infrared-of-f-22-raptor.html

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    9. The F-35 may have a high by-pass, but its exhaust was so hot it was melting USNs flight-deck. See here:
      https://navy-matters.blogspot.com/2017/12/f-35b-landing-considerations.html
      So a bit of hair-splitting here. the MIC has confounded what fighter pilots require with what stealth requires.

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    10. Missile at Mach 3 forms a heated cone with a much larger area than the pitot tube, not a valid analogy. As I said, the area of ​​the IR emitter is proportional to its IR signature, so the pitot everything is not a large IR emitter, even though it is very hot.

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    11. The engine of the F-35 is much more powerful than the engine of the Harrier, in addition to using PC. It has the highest by-pass ratio, serrated nozzle, air between the outer and inner petals and small holes in the inner part of the nozzle, all measures for IR suppression.

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    12. Ricardo, Its the engine of the F-35 that is melting the flight decks - not the Harrier. F-35 produces way (way) more heat. IRST only need to detect IR photons and a heated Pitot tube can be easily seen as a hot spot. there is video on this site - proving your assertions wrong. here it is

      https://theboresight.blogspot.com/2011/07/forward-looking-infrared-of-f-22-raptor.html

      The point is already moot because the USAF has confused thermodynamics of a fighter with stealth.

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    13. The intensity of IR radiation is not the issue. The only thing that doesn't emit heat is a 0 kelvin black body. it is what is the sensitivity of your IR photon detector. You should probably write Lockheed Martin and Boeing and tell them why their IRST21 doesn't work for stealth fighters. (thumps up)

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    14. I'm showing the basic physics of the IR emitter. A colder emitter can be detected farther than a warmer and smaller emitter. The whole pitot is very small, it will not sensitize the IR sensor so easily. Do you really think they just forgot a pipe over there?

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    15. The IR radiation arriving at the IR detector is proportional to the area of ​​the IR emitter. This is a universal formula. You are ignoring IR physics.

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    16. Basic physics, the IR radiation arriving at the detector is directly proportional to the area of ​​the source. What is the area of ​​a pitot tube near the area of ​​an exhaust nozzle? You can not escape the laws of physics. I leave the link with the formulation of IR radiation again:

      https://drive.google.com/file/d/1tO9kQAGIH5RQXLTHZM5MqfkSa5hIgcHG/view?usp=drivesdk

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    17. No i'm not. F-22 pitot tube is clearly visible in FLIR and so is consistent with any physical laws. You need to included heat intensity and the sensitivity of the detector and in the surrounding air temperature. Skyward-G can see an IR target regardless of aspect as slow as 300 knots. far slower than a stealth fighter will be flying. Your point is irrelevant because of this video. Stealth fighters are an inherent paradox. The best thing for a stealth fighter to do is to fly slow and at mid to low altitudes to try and mask its IR. All bad for air superiority and missile kinematics. So its hopeless. Either act like a B2 or act like a fighter. the USAF never figured out you cant do both. See here.
      https://theboresight.blogspot.com/2011/07/forward-looking-infrared-of-f-22-raptor.html

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    18. If someone would like to explain why the F-22 pitot tubes are clearly visible (their heat exciting the IR detector) in this video? please be my guest. Anyone? (thumbs up) https://theboresight.blogspot.com/2011/07/forward-looking-infrared-of-f-22-raptor.html

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    19. The image of a FLIR a few feet away does not say anything about the ability of an IRST against it to tens of miles, two completely different things. Anyone who knows the physics of the IR detector will say the same thing, pure myth the history of the pitot tube.

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    20. You just put it in your head that they forgot the pitot tube there and that now any IRST can detect a stealth within tens of miles. You sure have never seen stealth capability validation aircraft that have a huge IR sensor.

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    21. Hi Ricardo. don't get FLIR images confounded with IRST. The FLIR images simply shows that pitot tubes are in fact a high IR radiation emitter (otherwise they would not look different from the rest of the thermal color gray scale off skin of the F-22). And there are two of them. The rest of it in simply propagation physics and IR photon detection (and apparently some wiz-bang in the form of the IRST21 tech). Just because both the F-35 and F-22 have these protuberances is not our problem. Just because the USAF and Lockheed confounded what fighter jets need with stealth needs is also not our problem. Honestly, the last fighter jet Lockheed produced was the F-104. I don't know who at the Pentagon though it would be a good idea to buy another Lockheed fighter? Have you reviewed the combat and operational record of the F-104? Its a joke.

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    22. IRST versus stealth is much more myth than reality. The IRST only achieves maximum range when receiving prior indication of target. The FOV of an IRST is only 8 ° x 6 °, that is, it needs to know where to look to find a target far away. The validation of a stealth fighter passes through a flight where a modified Boeing uses 2 huge radars is two thermal sensors to validate its level of discretion.

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    23. The scanlimit for the ols-35 for example is: Azimuth +/-90 , Elevation -15/+60. You'll probably might have to take up your arguments up with the US-Navy and IRST21 team, (thumbs up).

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    24. I spoke FoV and not FoR. IRST has maximum reach with narrow FoV, it needs to know where to look.

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  3. Remember that the F-35 itself already uses IRST and low latency link for triangulation. Nothing new.

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    1. Hi Ricardo,
      you wrote: "Stealth losing to the IRST? How many fighters were killed by the IRST? 0. The IRST is far from threatening Stealth, it has an operational detection scale of less than 50km. All new hunting projects are stealth. His statement has no reference. The maximum range of IRST depends on weather conditions and a previous location of the target, far from having the same radar efficiency."

      According to Lockheed Martin, weather is not a limitation any longer for these new IRST sensors. From the article:"What makes the new IRST particularly capable is that it operates in the long wave infrared band, which allows the sensor to passively detect and track targets well beyond the range of the APG-79 radar. “It can see a hot airplane,” Kornegay said. “It has much longer range—it is a long wave long range IRST—so it can see much further than radar can.”

      Boeing has taken into account the traditional limitations of infrared sensors, where performance can be severely degraded by inclement weather—particular clouds and atmospheric moisture—when testing the new sensor, Kornegay said. The new IRST is so advanced that it still consistently generates tracks at extended ranges even taking into account inclement weather and other factors. “We’re not assuming a clear day,” Kornegay said."

      Remember that advanced solar cells still generate electricity on cloudy/rainy days because longwave IR still gets through.

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    2. Long-wave IRs are only efficient at high altitudes, at medium and low altitude medium waves have a longer range and have higher resolution to form an IR image of the target. IRST does not make a miracle, I repeat, how many fighters have been engaged and killed by the IRST? All new programs are stealth, this should give an answer on reality.

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    3. IR waves can go right through clouds and weather otherwise how do solar panels still make power when its overcast? IRST does not need to create IR imagery - only detect IR photons - which is a vastly different thing - and vastly more sensitive.

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    4. The F-35 IRST is included in our writing. Two IR sensors in the wing-roots on the YF-22 was deleted on the production aircraft.

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    5. The entire IR spectrum is heavily affected by weather conditions. Solar panels do not say anything about IRST. All stealth works the IR and RF signature, try to find the exhaust nozzle of an F-35 by the side aspect. The vertical stabilizer does not hide the exhaust nozzle by simple chance.

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    6. And on the other hand, no other fighter discussed on this site hides their exhaust nozzle any more or less than the F-35 does, furthermore, the nozzle on the F-35 is noticeably larger than other single engine fighters, I have seen an F-35 in person from distances between 10-20 meters at an air show, and have also seen an F-16 for comparison.

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  4. Ricardo-The Rafale has IRST as part of its OSF https://en.wikipedia.org/wiki/Optronique_secteur_frontal
    IRST 21 proved it self in fleet exercise 2017«The U.S. Navy demonstrated the capability of the networked IRST, DTP-N and TTNT during the service’s Fleet Exercise 2017 onboard a pair of specially modified Super Hornets. The feedback from the naval aviators who flew during the exercise was that the capability was “eye-watering”—they were developing weapons quality tracks on targets that they had never seen before, Kornegay said.»

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    1. OSF-IT the Rafale abandoned the IRST, below-expected performance, as well as the IRST Block I of the F/A-18E

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    2. https://www.safran-electronics-defense.com/aerospace/military-aircraft/optronics

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    3. http://rafalefan.e-monsite.com/pages/dossier-rafale-avionique/osf-optronique-secteur-frontale.html

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    4. OSF-IT does not have IRST in the French Air Force.

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  5. From the F4 stardart the Rafale will have a new IRST

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