Interesting Photos Show U.S. Air Force F-35A Stealth Jets Deployed To Japan About To Launch Without Radar Reflectors

U.S. Air Force Maj. Matthew Olson, F-35A Lightning II pilot from Hill Air Force Base, Utah, performs pre-flight checks before a training flight Jan. 25, 2018, at Kadena Air Base, Japan. The F-35A is deployed under U.S. Pacific Command’s theater security package program, which has been in operation since 2004. (U.S. Air Force photo by Senior Airman Quay Drawdy)

Some recent photos of the Hill AFB F-35s deployed to Kadena Okinawa, seem to suggest the 5th Generation fighters have started operating in “stealth mode”.

Stealth aircraft, such as the F-22 Raptor or the F-35 Lightning II 5th generation jets are equipped with Luneburg (or Luneberg) lenses: radar reflectors used to make the LO (Low Observable) aircraft (consciously) visible to radars. These devices are installed on the aircraft on the ground are used whenever the aircraft don’t need to evade the radars: during ferry flights when the aircraft use also the transponder in a cooperative way with the ATC (Air Traffic Control) agencies; during training or operative missions that do not require stealthiness; or, more importantly, when the aircraft operate close to the enemy whose ground or flying radars, intelligence gathering sensors.

This is what we explained explaining how the Israeli the heavy presence of Russian radars and ELINT platforms in Syria cause some concern to the Israeli F-35 Adir recently declared IOC:

[…] the Russians are currently able to identify takeoffs from Israeli bases in real-time and might use collected data to “characterize” the F-35’s signature at specific wavelengths as reportedly done with the U.S. F-22s.

In fact, tactical fighter-sized stealth aircraft are built to defeat radar operating at specific frequencies; usually high-frequency bands as C, X, Ku and S band where the radar accuracy is higher (in fact, the higher the frequency, the better is the accuracy of the radar system).

However, once the frequency wavelength exceeds a certain threshold and causes a resonant effect, LO aircraft become increasingly detectable. For instance, ATC radars, that operate at lower-frequency bands are theoretically able to detect a tactical fighter-sized stealth plane whose shape features parts that can cause resonance. Radars that operate at bands below 300 MHz (lower UHF, VHF and HF radars), such as the so-called Over The Horizon (OTH) radars, are believed to be particularly dangerous for stealth planes: although they are not much accurate (because lower frequency implies very large antenna and lower angle accuracy and angle resolution) they can spot stealth planes and be used to guide fighters equipped with IRST towards the direction the LO planes might be.

F-35s deployed abroad usually feature their typical four radar reflectors: to exaggerate their real RCS (Radar Cross Section) and negate the enemy the ability to collect any detail about their LO “signature”. As happened during the short mission to Estonia and then Bulgaria, carried out by the USAF F-35As involved in the type’s first overseas training deployment to Europe or when, on Aug. 30, 2017, four U.S. Marine Corps F-35B Lightning II joined two USAF B-1B Lancers for the JSF’s first show of force against North Korea: the F-35Bs flew with the radar reflectors, a sign they didn’t want their actual radar signature to be exposed to any intelligence gathering sensor in the area.

The two radar reflectors on the right side of the F-35A (the remaining two are located in the same positions on the left side). Image credit: LM (hightlight by Author)

Since they almost always fly with the radar reflectors, photographs of the aircraft without the four notches (two on the upper side and two on the lower side of the fuselage) are particularly interesting: for instance, some shots taken on Jan. 24, 2018 and just released by the U.S. Air Force show F-35As deployed to Kadena AB, Japan, in October as a part of the U.S. Pacific Command’s Theater Security Package program, preparing to launch without their Luneberg reflectors.

The lack of reflector on the top left position of this F-35 is pretty evident in the following photographs:

A U.S. Air Force F-35A Lightning II from Hill Air Force Base, Utah, goes through pre-flight checks prior to taxiing Jan. 25, 2018, at Kadena Air Base, Japan. The F-35A is a 5th-generation stealth fighter developed to safely penetrate areas while avoiding radar detection. (U.S. Air Force photo by Senior Airman Quay Drawdy)

 

U.S. Air Force Senior Airman Jacob Valdez, 34th Aircraft Maintenance unit crew chief, performs pre-flight checks prior to a training flight Jan. 25, 2018, at Kadena Air Base, Japan. The F-35A is a 5th-generation stealth fighter developed to safely penetrate areas while avoiding radar detection. (U.S. Air Force photo by Senior Airman Quay Drawdy)
U.S. Air Force Senior Airman Jacob Valdez, 34th Aircraft Maintenance unit crew chief, communicates with Maj. Matthew Olson, F-35A Lightning II pilot from Hill Air Force Base, Utah, before a training flight Jan. 25, 2018, at Kadena Air Base, Japan. The F-35A is deployed under U.S. Pacific Command’s theater security package program, which has been in operation since 2004. (U.S. Air Force photo by Senior Airman Quay Drawdy)

For comparison, the following photo shows one of the 388FW F-35A jets on the ground at Kadena in November 2017 with the radar reflector.

U.S. Air Force Staff Sgt. Patrick Charles, 34th Aircraft Maintenance Unit crew chief, goes through pre-flight procedures Nov. 16, 2017, at Kadena Air Base, Japan. Rotational forces are integral to increasing our military combat capabilities, which are essential to U.S. power projection and security obligations. (U.S. Air Force photo by Airman 1st Class Greg Erwin)

Obviously the lack of radar reflectors is not a big deal: during their deployment to RAF Lakenheath last year, F-35As of the 388th FW have flown without reflectors some local sorties with the 48th FW F-15E Strike Eagles (for example on Apr. 26, 2017). However, photographs of deployed F-35s without Luneburg Lenses are pretty rare and, for this reason, interesting and newsworthy.

 

 

About David Cenciotti 4450 Articles
David Cenciotti is a freelance journalist based in Rome, Italy. He is the Founder and Editor of “The Aviationist”, one of the world’s most famous and read military aviation blogs. Since 1996, he has written for major worldwide magazines, including Air Forces Monthly, Combat Aircraft, and many others, covering aviation, defense, war, industry, intelligence, crime and cyberwar. He has reported from the U.S., Europe, Australia and Syria, and flown several combat planes with different air forces. He is a former 2nd Lt. of the Italian Air Force, a private pilot and a graduate in Computer Engineering. He has written four books.

12 Comments

  1. Those Luneburg Lenses look quite small. I assume they increase the reflection at the higher frequencies but do nothing to increase the radar cross-section at VHF, where they’re quite tiny in terms of the wavelength.

    Can they be disabled in flight? That could prove quite useful. Lull an enemy into thinking he has a track and then suddenly disappear. Or have a trailing reflector that looks like a dozen of them and then suddenly discard it. “Where did all those planes go?”

    • The sad state of general knowledge in the western “civilization” area is
      appalling. The lack of will to gain a little more knowledge, before
      asking/making stupid questions/affirmations, even if just a click away,
      is even more so…
      The provided link, even if wrongly named (Burg=castle is not Berg=mountain, typical for the yank disability to cope with foreign names, and languages), would have offered an immediate, even if quite incomplete, and full of marketingdroid speak, answer to the question.
      Being a passive device, a Lüneburg radar reflector can’t easily be switched off.
      For those with a bit more inquiring minds, a Lüneburg lens (named after german mathematician Rudolf Karl Lüneburg) is a spherical concentrically graded refractive index optical device. The gradient profile is such chosen that one focal point is at infinity, and the other on the opposite surface of the sphere. To obtain a reflector, part of the sphere is metallized.
      The result is practically the same with a metallic disc reflector of the same diameter, always oriented towards the radar.
      The principle is similar to the ubiquitous cat’s eye retroreflectors.

      “For instance, ATC radars, that operate at lower-frequency bands are theoretically able to detect a tactical fighter-sized stealth plane whose shape features parts that can cause resonance.”
      Most ATC “radars” are so called “secondary surveillance radars” on 1030/1090MHz (Rx/Tx), which are useless without a transponder on the aircraft, so the assumption is basically moot.

  2. Even when fighters will be guided successfully to a stealth plane it will be very hard to lock-on for firing (IR-) guided weapons.

    • Modern IR seekers can even discern the image, with image recognition software.

      If you know where is the potential threat, receive a heat signal via ISRT, and launch for example, a long range IR missile like the R-27ET, he will never know what hit him.

      • I think the METEOR is like that.
        1. Locate enemy
        2. Launch
        3. When missiles in range it uses onboard IRST and sensors for the kill

        …but there are ways to even jam IRST

  3. Edit job required:

    This is what we explained explaining how the Israeli the heavy presence of Russian radars and ELINT platforms in Syria cause some concern to the Israeli F-35 Adir recently declared IOC:

    Ouch.

  4. They’re ready to destroy the PLAN AF at a moments notice. Let’s face it. China may bluster and threaten, but if it came to a naval or air fist-fight Japan and the U.S. would totally destroy their Chinese adversary.

    Japan is both re-militarizing and becoming militaristic again. The Chinese screwed up royally with their aggressive posture in Asia. They’ll some day live to regret it. Seems they forgot about Bushido – the code of honor and morals developed by the Japanese samurai. They’ll be harshly reminded.

    • unfortunately it would all be in vain considering both sides would nuke each other at the slightest hint of loosing a major battle

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