The US does not like Russia entering into strstegic relations with countries US deem necessary to it by ourchasing S-400s. In the case of Turkey, the US simply cannot trust Erdogan that he will not expose F-35s naked to S-400 radar.
Do you know that 60 yesrs ago USAF already has fuel additive known as A-50 that musks afterburner radar signature in A-12 (predecessor of SR-72) in what is known as plasma stealth? This fuel additives can easily be repurposed for F-35s. But the US very rarely used this additive so as not to provide the Soviets any idea of its existence.
https://www.thedrive.com/the-war-zo...d-plasma-stealth-by-burning-cesium-laced-fuel
I'm aware of the tech. Now let me again educate you why it never went mainstream. Because to sustain plasma cover is a maintainance nightmare. A lot of tech makes experimental / limited debut but never is useful for any practical purposes.
F35 is already maintenance intensive adding such impractical measure will just render it ground plane rather than flying one.
cesium fuel isn't the only attempt at plasma stealth on SR-71, it was also tested with an ionizer "gun" to generated an electron cloud to reduce radar reflections in KEMPSTER A program
Btw plasma stealth has already made comeback with hypersonic missiles. Which could actually sustain such temperature as they won't be reused.
Plasma stealth won't come back, it wasn't even all that effective in the first place.
One common myth that often get repeated when people talk about plasma stealth is the idea that the plasma sheath will absorb all radar frequency, but that can't be any further from the truth. Plasma cloud always have a frequency that depends on temperature, you can estimate the plasma frequency with this table
if you only look at that table, the common assumption is that the temperature (also higher the frequency) the better, but that is also incorrect
"The use of plasmas to control the reflected electromagnetic radiation from an object (Plasma stealth) is feasible at suitable frequency where the conductivity of the plasma allows it to interact strongly with the incoming radio wave, and the wave can either be absorbed and converted into thermal energy, or reflected, or transmitted depending on the relationship between the radio wave frequency and the characteristic plasma frequency. If the frequency of the radio wave is lower than the plasma frequency, it is reflected. if it is higher, it is transmitted. If these two are equal, then resonance occurs."
https://www.researchgate.net/public...IPULATION_OF_RADAR_CROSS_SECTIONS_WITH_PLASMA
To make it easier:
let say the plasma frequency of your plasma sheath is 8 GHz
If the incoming radar or communication wave is 7 GHz, it is reflected
If the incoming radar or communication wave is 8 GHz, it is absorbed
If the incoming radar or communication wave is 9 GHz, it goes through the plasma sheath
In others words, plasma sheath can reduces your RCS in some frequency and increase it significantly at some frequency
And once just having a lurenburg lens doesn't cover up f35. If that worked wouldn't other 4 gen plane would reduce their rcs by same degrees?? Like I said before critical thinking is missing. F35 is a good solution. Mass production makes it even better but it's not the panacea.
Also if USA can't trust turkey with Russian spys how it trust that Italian won't open f35 for China? Italy is more dependent on China then turkey will ever be on Russia? Another critical question.
Luneberg lens are generally a corner reflector used to increase your RCS. You can't make your RCS smaller with it. There are many parts of stealth design that is impossible to see from outside regardless what kind of camera you use, for example, the internal edge treatment to minimize edge scattering
