Monday, January 7, 2013

F–35: how "stealth" is done

One of the things we said on this blog is that stuff does not define the F–35. Stealth is simply one of its tools, one of its capabilities.

However, critics will tell you, or at least try to, that stealth is overrated. In fact, it's not. It is just over-hyped. But it is a critical capability.
In short, the four most important aspects of stealth are "shape, shape, shape and materials," to quote Lockheed Martin analyst Denys Overholser, whose pioneering work resulted in the F-117 Nighthawk, the world's first operational stealth warplane.

But in addition to shaping and RAM, the Pentagon's current stealth planes -- the B-2 Spirit bomber, the F-22 Raptor fighter, the RQ-170 Sentinel drone and the in-development F-35 Joint Strike Fighter -- boast other, lesser-known qualities that help them avoid detection. ...

These other stealth enhancements include: chemicals to eliminate telltale contrails; sophisticated, untraceable sensors and radios; specially designed, hard-to-detect engine inlets; radar-canceling paint; and cooling systems for reducing a plane's heat signature.
Of course what those three paragraphs mean, is that anyone or any nation can claim to have  a stealth aircraft, however claiming it, even making one that looks like a stealth airplane, doesn't mean it has the same capabilities as the F–22 or the F–35. There's a lot more to stealth than just a paint job.

 For instance:
Radar is like long-range eyes in the sky for modern warplanes. Without this sensor, a plane is more or less flying blind. The problem is, radar works by emitting energy -- lots of it. And that can be detected by an enemy's own passive radar receptors in the same way that someone standing in a dark room can track the movements of another person carrying a flashlight.

The F-22, F-35 and B-2 work around this problem by practicing what Aviaton Week stealth guru Bill Sweetman called "emission-control principles." With the Raptor, emissions from the jet's APG-77 radar "are managed in intensity, duration and space to maintain the pilot's situational awareness while minimizing the chance that its signals will be intercepted." In other words, the plane's software is smart enough to use just enough energy to find and track targets -- and no more. The B-2 and F-35 have electronically-scanned radars that are similar to the Raptor's and probably employ the same tactics.

Plus the Raptor and Joint Strike Fighter both have non-emitting backup sensors that can fill in the gaps in the radar coverage. The F-22's ALR-94 radar-warning receptors are among the most sensitive ever designed and can accurately, and "silently," detect most radar-using targets at long range. The F-35 boasts a powerful set of cameras that achieve the same effect.
So when you see the claims that all stealth planes are equal, and that being the case, the F–35 is inferior, it is highly likely those making the claims don't know what they're talking about.


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