Tecnologia stealth al plasma

[WillyI]

Ho letto lungo questi mesi gli interventi di alcuni utenti che accennavano (senza peraltro produrre alcun documento) ad una tecnologia russa che permetterebbe di ottenere invisibilità ai radar grazie ad una nuvola di plasma intorno all'aereo. Incuriosito ho fatto una breve ricerca io stesso. Vi posto l'articolo che ho trovato più interessante:


G

[WillyI]

Stealth's Radioactive Secret

This is the first in two-part series from exotic weapons guru David Hambling.
There’s a simple technology that could transform civil aviation, slashing fuel consumption, reducing greenhouse emissions and cutting noise. The problem is, nobody knows about it – yet. It's a military secret.
The way technology migrates from classified weapons programs to everyday life is the theme of my book, Weapons Grade. (Did I mention it was out in paperback this week?) We wouldn’t have jet aircraft, computers or satellite communications without such programs. But when they stay secret, the public benefit is lost. What would have happened to the electronics industry if the transistor had not been declassified in 1949?
Plasma aerodynamics offers tantalizing promises of improving aircraft performance. By producing a thin layer of charged particles around an aircraft you can change the behavior of the boundary layer, significantly reducing friction. The charged layer also absorbs radar, improving stealth.
When my colleague Justin Mullins wrote about the subject for New Scientist magazine back in 2000, it seemed to be an obscure Russian technology dating from the late 70’s which the US was just beginning to examine. But it offered real benefits, with a potential drag reduction of up to 30%.
“A cut in drag of 1 per cent means you can increase an airliner's payload by about 10 per cent, or it could simply fly farther or faster,” Mullins pointed out, “Just imagine the effect this could have on cash-strapped airlines.”
The Russians seemed to be years ahead, even marketing a plasma stealth add-on device said to reduce radar returns by a factor of a hundred.
He concludes by wondering if the technology can actually work in practice.
“Either the new labs are a huge waste of time and money, or the American military knows something we don't.“
As it turns out, they certainly do.
A lot of information on stealth disappeared from the public domain decades ago when the whole subject turned black. Which was why I was surprised to find the original patent for plasma stealth still intact.
Patent 3,127,608 is called "Object Camouflage Method And Apparatus," and "relates to a method of making aircraft or other objects invisible to radar." The inventor, one Arnold L. Eldredge, describes the theoretical basis of plasma stealth accurately.
The most surprising thing is the date. The patent was filed on August 6th, 1956. The technology has been around for fifty years.
But the big problem is with his apparatus – Eldredge uses an electron gun, which would be way too big to carry on an aircraft. In fact, that’s a problem with this whole plasma idea. Apparatus to generate the millions of volts needed is big, bulky and impractical; even these days the Russians are talking 100 Kg and tens of kilowatts.
But there is a way - check out Patent 4,030,098 (1962) “Method and means for reducing reflections of electromagnetic waves “ – assigned to the Secretary of the Army and the rather similar Patent 3,713,157 (1964) belonging to North American Aviation, later absorbed by Boeing – “Energy Absorption by a Radioisotope Produced Plasma”
Both of these use the same basic concept: a coating of radioactive material producing a flux of either Alpha of Beta particles ionize the air, producing the desired layer of plasma. It’s a clever solution. Radioactive paint weighs virtually nothing, does not require any power input and can be dirt cheap. One of the suggested emitters is Strontium-90, which is produced in abundance as a waste product by nuclear reactors.
It’s also quite safe. With a thin protective coating to prevent it from flaking off, the soft radiation (unlike dangerous Gamma radiation) is not a hazard to pilot or maintenance personnel. This type of material is only dangerous if inhaled or ingested.
I checked out the idea with some people who know about these things - Martin Streetly, Editor of Jane's Radar & Electronic Warfare Systems and Professor Igor Alexeff, former President of the IEEE Nuclear and Plasma Sciences Society and an authority on plasma technology.
Both confirmed that the idea, though exotic, was sound enough in theory. Interestingly, neither had come across the idea before. And both observed one obvious disadvantage from the point of view of stealth. The radiation levels involved – 10 Curies per square centimeter – would give the plane a visible glow at night, making it a beacon to enemy air defenses.
Did this problem mean that the whole idea was shelved - or were radioactive stealth coatings taken further?
Glowing Planes, Hidden Bombers

This is the second in a two-part series on radioactive stealth from exotic weapons guru David Hambling. Check out part one here.
Back in the 60's, there was considerable work done on developing radioactive coatings which would have the double benefit of absorbing radar and reducing drag. We know that from the patents we looked at in part one. What aircraft would have had such coatings?
In the late 1950’s there had been several attempts to reduce the radar cross-section of the U2 spy plane under the name Project Rainbow, detailed here. These included the ‘trapeze’, an arrangement of poles and wires, and ‘wallpaper,’ material printed with with radar-aborbent circuitry. The results were not satisfactory – Kelly Johnson called the modified U2s ‘dirty birds’ because of the effect on their aerodynamics which lost them several thousand feet. Even worse, the ‘wallpaper’ caused overheating with the loss of one aircraft and the death of test pilot Robert Sieker.
A coating that reduced radar returns and improved aerodynamics would have been the answer – but at the price of a visible glow at night. So, were there any sightings of mysterious glowing U2s? A CIA report on the CIA's Role in the Study of UFOs, 1947-90 states:
According to later estimates from CIA officials who worked on the U-2 project and the OXCART (SR-71, or Blackbird) project, over half of all UFO reports from the late 1950s through the 1960s were accounted for by manned reconnaissance flights (namely the U-2) over the United States. (45) This led the Air Force to make misleading and deceptive statements to the public in order to allay public fears and to protect an extraordinarily sensitive national security project.
Why would anyone report a U2 as a UFO?
The early U-2s were silver (they were later painted black) and reflected the rays from the sun, especially at sunrise and sunset. They often appeared as fiery objects to observers below.
I leave it to those who compile statistics on flying saucers to say how many glowing UFOs were sighted under these conditions and how many appeared to be luminous on their own account. Note also the wording in Patent 3,713,157 which says that the plasma cloud produces a combination of ‘absorbtion, reflection, refraction and diffraction’ across frequencies including visible spectrum, which would certainly alter the appearance of an aircraft, perhaps to the point of making it an unrecognisable blob.
A radioactive coating would be unlikely to be applied to the entire aircraft – as Martin Streetly of Jane’s pointed out to me, this would immediately block the aircraft's own radar, communications and navigation aids. However, a coating on the locations contributing most to radar returns – inlets and wing-body junction – would have a significant effect, and a coating along the leading edge would give the desired reduction in drag. It might even be possible to have coated surfaces which could be covered or uncovered as needed.
Radioactive coatings would cause a major disposal problems. It is alleged that workers at Groom lake - 'Area 51' - were harmed by carcinogens dumped there. The suit was dismissed in 1996 because for reasons of security the materials involved could not be disclosed; but the suggestion is that the material was chemical waste rather than radioactive.
Given that the radioactive plasma coating was known to improve aerodynamics and stealthiness in the 1960’s, we would expect the next step to be a way of achieving the same benefits without radioactivity.
This brings us to the B-2, an aircraft with has long been the subject of speculation. Even respected aviation writer Bill Gunston has commented on suggestions that the B-2 employs a system which charges the leading wing edge to ‘millions of volts’. (Interestingly, most such speculation is tied up with ideas of ‘electrogravitics’, anti-gravity and alien technology, which belong firmly in the disinformation category).
This would chime with a comment in Ben Rich’s book about the Skunk Works . He could not believe that Northrop’s stealth bomber design was 10% more aerodynamically efficient than Lockheed’s competing design, which was externally similar (page 338 in the Warner edition). Perhaps Northrop were exagerating, as Rich suggests; but perhaps their plane had a secret advantage.
Many have commented on a photograph of a B-2 from Edwards AFB (published in Air Forces Monthly in October 2000) in which the wing seems to be enveloped in a faint glowing cloud. This was explained by the Air Force as water vapor, but some commentators have argued that such a cloud would not form simultaneously above and below the wing.
See also the discussion and perhaps anomalous picture here.
The USAF appears to have been using plasma aerodynamics for decades. The Russians certainly know all about it , as does anyone who has bought the technology off them. According to the patents it has additional benefits too – it can muffle the noise produced by engines as well as preventing contrails from forming.
The only people not enjoying its benefits are the civilian taxpayers who funded it in the first place.

[WillyI]

Se è vero che questa tecnologia permette anche di ridurre il "drag" cioè la resistenza aereodinamica, le aplicazioni civili potrebbero portare ad una seconda rivoluzione low-cost in ambito civile. Perchè Boeing e Airbus non hanno mai implementato queste tecnologie?

[yurj]

le tecnologie militari, per l'ignoranza dei militari, non vengono date ai civili.

E poi si si chiede chi frena lo sviluppo...

[Ibonz]

le tecnologie militari, per l'ignoranza dei militari, non vengono date ai civili.

non subito, almeno.

E poi si si chiede chi frena lo sviluppo...

è un pò esagerata come affermazione....

[WillyI]

le tecnologie militari, per l'ignoranza dei militari, non vengono date ai civili.

E poi si si chiede chi frena lo sviluppo...

Hai ragione, in ambito civile arrivano dopo. Molto dopo. Ma non certo perchè i militari siano degli ignoranti..

[RUS]

Ho letto lungo questi mesi gli interventi di alcuni utenti che accennavano (senza peraltro produrre alcun documento) ad una tecnologia russa che permetterebbe di ottenere invisibilità ai radar grazie ad una nuvola di plasma intorno all'aereo. Incuriosito ho fatto una breve ricerca io stesso. Vi posto l'articolo che ho trovato più interessante:


G

Io sapevo che i russi sono arrivati al terzo stadio, eliminando molti difetti alla strumentazione del plasma, il resto è tutto segreto.

[Cesare]

Curioso che i russi, pur essendo al primo posto nell'ideazione delle tecnologie stealth, non abbiano prodotto aerei che ne facciano uso. Evidentemente non erano utili alla strategia sovietica, incentrata sul numero e sulla potenza di fuoco.

[Iron81]

Curioso che i russi, pur essendo al primo posto nell'ideazione delle tecnologie stealth, non abbiano prodotto aerei che ne facciano uso. Evidentemente non erano utili alla strategia sovietica, incentrata sul numero e sulla potenza di fuoco.

Di cose prettamente militari non so granchè, infatti di solito leggo e basta queste discussioni... però, considerato che (a quanto mi risulta) la tecnologia stealth mi sembra abbia cominciato ad esprimersi materialmente a fine anni '80 e poi negli anni '90... beh, i russi non avevano alcuna possibilità di produrre nuovi modelli... soprattutto di quel costo!
Poi ci sta anche che dica cappellate io...

[WillyI]

Io sapevo che i russi sono arrivati al terzo stadio, eliminando molti difetti alla strumentazione del plasma, il resto è tutto segreto.

Cioè, scusa? hai qualche dettaglio in più?