Aircraft Stealth Technology
In order for certain military aircraft to evade detection, stealth technology was created. The concept of stealth employs numerous design features and technologies. Aircraft stealth technology was first developed to hide the airplane from radar. From there, the concept has grown and developed.
Radar antenna will send out radio energy which will bounce-off, or reflect off an object, back to the antenna. The radar antenna then calculates the time it takes for this energy to return and can then tell its operator the distance of the object from the radar antenna. The design of aircraft made them easy to spot with radar; hence the need arose to decrease the radar cross section of certain military aircraft (how large the airplane looks on the radar at a particular angle and distance). In order to prevent radar detection, engineers needed to design stealth aircraft with the ability to deflect or absorb radar energy.
Special materials are necessary to absorb radar energy. These are typically applied in paint form. The structural design of the aircraft is important for deflecting radar energy. Whilst your average airplane has a more rounded shape, stealth aircraft are designed with sharp edges and flat surfaces so as to reflect the radar energy in another direction. The engine inlets have to be built so that radar energy rebounds within the inlet and is not bounced back to the radar antenna by the turbine blades. By using such technology, the first stealth airplane, the F-117A, would appear as the size of a bird on radar.
Of course, radar isn’t the only means of aircraft detection. Hence, other stealth technologies have been developed. If an aircraft can remain subsonic, it will not be possible for it to be tracked using its sonic boom. Typically stealth planes will be painted in dark, matte colors and only fly at night. Gray paint is used in daylight stealth aircraft. An infrared signature is typically left by the exhaust plume of an aircraft. To lower this signature a slit-shaped tail pipe is used. Also, cool air can be pumped into the exhaust. The design of the aircraft should also take into consideration other forms of energy such as communications systems and onboard radars.
From the above we can clearly see that several technologies should be used together for stealth aircraft. It is important that technologies develop and grow and this can certainly be seen in the field of stealth.