Written By: Amir Atta
If there’s anything that the World Wars have shown the nations, it’s that you always have to stay ahead of everyone in terms of military strength. Following the Second World War, countries across the world have become wary of direct conflict and have instead adopted a more subtle approach of stealth, sabotage and infiltration.
Aircraft have seen the biggest improvement in this sector as a fighter jet’s success depends on its ability to infiltrate enemy's lines, hit its targets and get out unnoticed. Such airborne jets can easily succumb to enemy's fire after being detected by radar systems. Thus the need to nullify enemy's radars in order to improve the effectiveness of jet aircraft arises.
How Does Stealth Technology Work?
Stealth jet fighters are designed to diffuse signals from all types of radars. While it is not possible to make aircraft completely invisible, conventional radars can be made ineffective against stealth aircrafts.
Stealth is a combination of passive low observable features and active emitters. These, alongside planned mission maneuvers, reduce an aircraft’s radar cross-section (reflection of radar signals). Turning or opening the bomb bay can double a jet fighter’s radar signal return.
However, beating radar signal is only one of the five factors in making a truly stealthy design. The designers also need to make it harder for heat-seeking missiles to detect a plane. Naked eye identification and noise are two factors which can let anyone identify the location of a jet. Radio transmissions to (and from) an aircraft also need to be controlled such that the enemy cannot triangulate the location using the communication signals.
At the very least, a stealthy aircraft needs to comply with the following guidelines:
● Hide thermal emissions
● Alter general configuration, like split rudder, to minimise radar detection
● Reduce radar detection when opening weapons bay
● Avoid detection in adverse weather conditions
The goals for designing a stealth based jet fighter are relatively simple when you consider the several limitations of such designs.
Initial designs had minimal radar interference but they faced control issues. Such planes required constant flight corrections from a fly-by-wire system. The most popular stealth bomber, the B-2 Spirit, was based on an unconventional design from 1940s to increase stability.
The hot exhausts sonic boom when flying faster than the speed of sound and surface heat from flying at such speeds increases infrared footprint. Designers had to sacrifice maneuverability to deal with the issue. More recently though, at least three stealth jet fighters have the latest performance characteristics, thanks to superior flight control systems, engines, airframe designs and materials.
Even with current technology, stealth aircraft are vulnerable to detection during and immediately after using their weapons or releasing payloads. Even older radars can detect stealth jet fighters when hidden weapons surface. Even though aircraft can reacquire their stealth after using the weapons, any fast surface-to-air defence system has the opportunity to engage the aircraft.
Workarounds are employed to avoid temporary detection. Bomber aircraft take flight at very high altitudes which can make it virtually impossible for defence systems to engage the plane. Fighter aircraft (only two until now) can open bays, release payload and return to stealth mode in less than a second, reducing the overall vulnerability time. There still are problems when some weapons require the weapon's guidance system to acquire the target while still attached to the aircraft. Trade-offs have to be made when deciding between the destructive ability of a plane and its stealth capability.
Since stealth aircraft carry all fuel and armament internally, the payload has to be reduced in weight or size.
Modern stealth jet fighters make use of a sensitive signal absorbent skin called Radar-Absorbent Materials (RAMs). These materials contain carbon black particles and some have tiny iron spheres. Other materials are classified and still not known. This material can be damaged very easily.
Stealth aircraft require large amounts of investment, usually in billions of dollars, before a working unit can be manufactured. The cost of such jets is usually much higher than conventional models. One of the U.S. programs for stealth jet fighters costs nearly $1 trillion.
Passive radars, bistatic radars and multistatic radars can detect some stealth aircraft. Modern radar systems like Synthetic Aperture Radar (SAR) and Associative Aperture Synthesis Radar (AASR) can employ inexpensive means to locate low observable targets.
Similarly, Schlieren (atmospheric disturbances) can also be used to identify stealth aircraft. Passive signature intelligence can be used to detect objects between space and earth. Once a plane is detected, its stealth signature can be loaded into a library such that it can enable live satellite search for stealth fighters.
According to some analysts, Infra-red search and track systems (IRSTs) can be used to nullify the stealth system of some aircraft by using their frictional heat to identify them. Long Wavelength Radars are also effective against some stealth technologies. OTH (over-the-horizon) radar is a new technology which can overcome certain stealth characteristics.
China also claims to have developed a radar system capable of detecting all stealth aircraft with impunity.
Modern Stealth Jet Fighters
Until now, only the U.S. has used stealth aircraft in combat. It was used first in Panama in 1990 followed by the Gulf War, Kosovo conflict, Afghanistan, Iraq and recently in Libya. Some of the stealth fighters and bombers are listed below:
● F-35 Lightning II (USA)
● B-2 Spirit (USA)
● F-22 Raptor (USA)
● Chengdu J-20 (China)
● Shenyang J-31 (China)
Unmanned stealth aircraft are owned by several military forces while working manned aircraft are still scarce. Most have faced issues leading to cancellation of such projects. Russia, India, Iran, Sweden and the U.S. are in process of developing new stealth aircraft.
Due to the large investments and huge amounts of research required for such projects, it is hard to say major improvements or newer models from any of the countries could be seen in the near future.
The writer is a Data Network expert. He is the founder and CEO of ProPakistani.pk