China Won’t Rule The Skies

A guest piece in The Diplomat:

Obviously, if China were to successfully field a fighter with even a fraction of the F-22’s versatility or survivability, that would present major problems for neighbours such as Taiwan—there’s no air surveillance radar in the world today that can successfully track a fifth-generation fighter.

Actually every stealth aircraft has some slight radar return and just about every air surveillance radar can track every stealth aircraft, if it is close enough.

A radar warning device, like the fuzz buster for a car to help prevent speeding tickets, can detect a radar out to a distance governed by the power of the radar divided by the square of the distance. Therefore a radar that is four times as bright can be detected twice as far away. The reason for this is that doubling the radius of a sphere increases its surface area by four times, but increasing the power of the radar by four times keeps the same energy striking a limited surface like the antenna of the detector.

Radars work by detecting the reflection of their own transmissions on the targets. So a target that is twice as far away will have a fourth the energy striking it and this return spot will then be divided by another factor of four on the return trip. Therefore to detect the same target twice as far away requires a radar with 16 times the power. Distance applies as the fourth power.

Now let's mount the fuzz buster on a stealth car with the same radar return as the F-22 Raptor, that is to say it reflects radar waves as if it where a steel marble. This gives the same result as reducing the power of the radar by the ratio of the change in the Radar Cross Section (RCS). A car has a front surface area of say two meters and no concern for stealth in its design so let's assume that it has an RCS on the order of one square meter. The steal marble has a surface area 10000 times smaller and so is detected at a tenth of the usual range. The cops could search at the usual range by using a radar that is 10000 times more powerful. (However microwave ovens are a spinoff from radar research, which is why navy ships and fighter aircraft have danger signs marking their radars.) But this dangerously powerful traffic radar could be picked up by the fuzz buster from a hundred times further out so the driver would have plenty of warning.

And that is how the F-22 Raptor avoids being seen on radar. It sees the radars first (ground or air based) and avoids them.

Now, who was this person who wrote the article who didn't know anything about radar?

Dr. Loren Thompson is Chief Operating Officer of the Lexington Institute, located near Washington, D.C.

Henry J. Cobb