Can Stealth Stay Stealthy?

By Stephen Bryen
Thursday, July 7th, 2016 @ 12:02PM

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In 1961 Piotr Ufimstev working in the USSR, created the mathematical theory and tools to do a finite analysis of radar reflection, meaning that the idea of how to achieve stealth was born.  His writings were translated and shared in the United States and by 1970 Lockheed started to apply the theories to real airplanes.

As the US undertakes two hugely expensive projects, the F-35 Joint Strike Fighter, a program that will cost $1.5 trillion and the B-21 bomber, a program that will cost at least another $1 trillion, the question is whether the main attribute, stealth protection, is going to assure US air dominance.  History says maybe not.

Even before Ufimstev, two designers in Nazi Germany Reimar and Walter Horten developed a “flying wing” that was jet powered.  Known as the Ho-229 (there is only one surviving platform now under restoration by the Smithsonian), the aircraft featured two jet engines and a special wooden, laminar design.  The Horten’s developed a special paste that they put between the wood layers made up of glue and coal dust, which they claimed after the war was intended to reduce the radar reflectivity of the Ho-229.  The airplane never became operational, but one feature of it was to reduce its radar cross section by about 20% against English radar air defenses.  Engineers have calculated that this would reduce the time the old British radars could detect the Ho-229 from 19 minutes to 8 minutes.  Probably that would confer sufficient advantage for the planes to enter British airspace and carry out missions. While it has not been estimated, the design might also have made proximity fuses on anti-aircraft weapons less effective.

The first US stealth aircraft was the F-117A. The platform was developed in secret at Lockheed’s facility, popularly known as the Skunk Works, in Burbank, California While the plane became operational in 1983, its existence was not known to the public until late in 1988.  It was used in the Panama war in 1989 where two of them dropped bombs on a Panamanian airfield.  It saw its first major use in Yugoslavia where the F-117A was used in bombing missions, especially in and around Belgrade.   On 27 March 1999, an F-117A was shot down by a Russian-made Neva-M missile fired from an SA-3 Pechora-M battery.  The F-117A was picked up by an old Russian radar, and the two missiles were radio-guided to the target.  One of them failed to explode; the other brought the plane down.  The pilot, Dale Zelko, survived and was rescued the next day.

The F-117A was a very good stealth design, so one can say that it was already known in 1999 that a stealth aircraft could be detected by radar and that missiles could successfully shoot down a stealth aircraft.

Even so, the US continued working on stealth.  This was the moment when there was no intelligence evidence that either Russia or China was working on any platform with stealth characteristics, even though the Russians certainly were familiar, thanks to Ufimstev and others, on stealth techniques.

One of the reasons, according to Russian sources, is that aircraft designers in Russia (at Sukhoi, Mikoyan, and Tupolev) did not like the trade-offs that a stealth design imposed. Perhaps the Russians lacked the applicable technology to produce a stealth platform or, more than likely, the sensitive equipment and know how actually to refine and test a stealth system.  But the Russians argued, not wrongly, that there were three problems with stealth. The most serious problem is that stealth designs severely limit the agility and maneuverability of a jet fighter or fighter bomber.  Russian designers put a high premium on agility in combat, anticipating that getting out of the way of enemy fighters and missiles was of critical importance.  And they could see, in looking at US designs, that maneuverability was a major weakness (and still is).

The Russians had other objections.  In a stealth aircraft, the weapon stores are kept internally.  And, like a submarine getting ready to launch a torpedo, the doors must be opened to expend the bombs and missiles onboard.  But opening the doors immediately lights up enemy radars and “de-stealths” the platform.  Indeed, this is what happened to the F-117A in Yugoslavia.

The Russians also started to wonder whether more advanced radars could defeat stealth, or at least make it easier to identify and target stealth platforms.  Since stealth designs are pegged on frequencies used widely by adversary radars, namely X, Ku and C band, using, alternative frequencies could beat the protection of stealth planes including the F-22 and the F-35, as well as platforms like the B-2 bomber and stealthy drones.

The Russians are developing two radars – L-band radar which is being mounted in the wing roots and vertical tail of its latest fighters such as the SU-35, and ground-based HF radars that bounce signals off the ionosphere, making over the horizon detection possible.  HF and L-band radars can see threats from stealth planes.  Thanks to new technology that includes advanced semiconductors and fast computers, the limitations of both these systems are being overcome.  Furthermore, the radars can be enhanced more in future and synchronized with standard X-band systems and other sensors such as optical, laser and thermal imaging systems.

The F-35 and B-21

The F-35 project is a semi-stealth platform that exploits advanced radar technology, beyond visual range weapons, and sophisticated targeting systems that cooperate with another F-35’s when used to attack targets.  It is a formidable platform designed to take out enemy radars and missile sites and then act as an attack platform.  Will the F-35 be able to do this?  A lot depends on whether it can fend off enemy BVR air to air missiles and ground-based mobile anti-aircraft missiles.  While the F-35 is built to be an absolute air superiority weapon, it has to be recognized that against a well-prepared adversary it will not likely enjoy complete air dominance.

The B-21 bomber, the latest stealth project, is aimed at designing a bomber that can’t be easily detected by L-Band or HF type radars, which means that the bomber will have a lot of physical and performance limitations to reach this goal.  It is far from proven whether it is possible to build a new bomber that has these characteristics, especially since advances in electronics (available to Russia and China) is outpacing stealth. Thus, the issue is, before we invest more than a trillion dollars in a program with somewhat marginal utility, is whether the B-21 can achieve its goals? There is a marked Pentagon tendency to cover up weaknesses and support programs that should be scrapped.  Will anyone have the guts, should the B-21 not meet its design goals, to dump the project?

Stealth is an idea that seems on the downward slope of the bell curve.  For the next decade, it will still play a useful role, but later, other technologies will be needed for the US to maintain a credible Air Force.






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