The radar antenna measures the time it takes for the reflection to arrive, and with that information can tell how far away the object is. The metal body of an airplane is very good at reflecting radar signals, and this makes it easy to find and track airplanes with radar equipment.
The goal of stealth technology is to make an airplane invisible to radar. There are two different ways to create invisibility:. Most conventional aircraft have a rounded shape. This shape makes them aerodynamic, but it also creates a very efficient radar reflector.
The round shape means that no matter where the radar signal hits the plane, some of the signal gets reflected back:. A stealth aircraft, on the other hand, is made up of completely flat surfaces and very sharp edges.
When a radar signal hits a stealth plane, the signal reflects away at an angle, like this:. In addition, surfaces on a stealth aircraft can be treated so they absorb radar energy as well. The overall result is that a stealth aircraft like an FA can have the radar signature of a small bird rather than an airplane.
The only exception is when the plane banks -- there will often be a moment when one of the panels of the plane will perfectly reflect a burst of radar energy back to the antenna. Sign up for our Newsletter! Such signals are difficult to lock onto.
Bright peaks are accomplished by aligning all the plane's panels in perfect parallel so that the light bouncing off of them interferes constructively.
It also helps to be dressed in black. Stealth planes are coated with radar-absorbent materialssubstances with high absorbency of light at radio frequencies. One such coating is iron ball paint, which contains microscopic iron spheres that resonate in tune with incoming radio waves and dissipate the majority of their energy as heat, leaving little to bounce back to detectors. Stealth planes must not only evade radar, but heat-sensing missiles as well. In the case of the FA Nighthawk, its turbofan engines vent through thin nozzles that spread out the heat they produce.
Heat shields are positioned below the nozzles for further protection. Stealth often comes at a cost: Edgy designs often render stealth fighter jets non-aerodynamic.
Furthermore, the lack of a vertical tail which would back-reflect incoming radio waves can make them unstable, as military expert Bill Sweetman explained in his books "Inside the Stealth Bomber" Zenith Press, and "F Raptor" Zenith Press, Nonetheless, the benefits of taking the enemy by surprise outweigh the costs.
Reuters reported that China's J jet is still years away from large-scale production and use, making the U. Air Force's F and B-2 fleets the only stealth planes currently operational.
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