The origin of Stealth Aircraft
Foiling the detection of aircraft by Radar was first hypothesised by British engineers in the 1940s. However, it was not until the late 1970s that a significant grasp was attained over the principles of radar functioning that an attempt to foil it could be carried out. Low observable technologies would reduce the radar return making it more difficult for adversaries to track and engage attacking aircraft. It involved reducing the radar signature of the aircraft to thwart enemy radars. The primary method to reduce the radar signature was to reduce the aircraft’s radar cross-section (RCS). Research was carried out in special shapes and materials that reduced the radar cross-section. This paved the way for a new aircraft category that could enter enemy territory, conduct operations, and devastate the enemy. These came to be called stealth aircraft.
Stealth Technologies
Reducing RF Emission
A combat aircraft has multiple Radar Warning Receivers (RWR) onboard. These alert the pilot when they receive radar signals from enemy aircraft. Reduction of these and other emissions from communication systems or any RF leaks onboard the aircraft is imperative for stealth.
Reduction of RCS and Radar Signature
This has been one of the most popular methods to make an aircraft stealthy. This is achieved by directing the incoming radar signals away from the receiver, thus effectively the area the radar “sees”. Modern aircraft have extremely low RCS that can be compared to that of small birds or large insects. Serpentine air intakes help reduce the RCS of the aircraft. Many stealth aircraft use Radar Absorbing Materials (RAM) and ablative paints to reduce the probability of radar detection.
Acoustic Signature
One of the requirements of a stealth aircraft is a low acoustic signature. With advances in technology, engines have become extremely efficient and silent. However, the sonic boom is a source of major noise in supersonic aircraft.
Visual Signature
Modern aircraft use camouflage paint or other coatings to reduce visual signature. Grey paints are especially effective. Minor but important aspects such as contrails (vapour trails produced by engine exhaust) and sunlight glinting off the plane’s cockpit should be addressed.
Infrared Signature
Modern aircraft are equipped with IRST (Infrared Search and Track) systems. These systems lock on to the aircraft’s heat signature and use this to target the aircraft. The engine exhaust is the primary source of heat onboard an aircraft. This is reduced by reducing the cross-sectional area of the exhaust plume and maximising the mixing of hot exhaust and air. Circulating the fuel (like a heat exchanger) around the exhaust can help to bring down the overall temperature of the exhaust.
Why Are Stealth Aircraft in Rage?
Imagine an aircraft that enters enemy territory, conducts its mission, and then returns home. All this while, the enemy is unaware that such an operation is taking place. This is the advantage of a stealth aircraft. The enemy’s reaction time is reduced drastically. The operation can be conducted, and the pilot returns to base safely while the enemy is astounded and left in shock. These aircraft are advantageous when it comes to offensive counterattacks. They are also extremely helpful during defensive operations. It can fire a missile targeting an enemy aircraft, and the enemy won’t be able to determine where the missile was fired from, making it easy to neutralise enemy aircraft.
The Flip Side Of The Coin
On the other hand, stealth aircraft come with their own set of challenges. They are insanely expensive to develop, build and operate. They come with reduced payload due to the presence of internal weapon bays, making them less cost-effective. The probability of detection of stealth aircraft increases manifold when its weapons bay is open. Their speed and manoeuvrability are severely restricted when compared to conventional military aircraft.
Can They Be Countered?
Long-range aerial surveillance radars operating on Very High (VHF) and Ultra High (UHF) frequencies can be used to detect these aircraft. China is said to have developed quantum radars. Although these claims can’t be verified, they can pose a serious threat to stealth aircraft if they are true. Stealth aircraft haven’t been able to snuff out their heat signature completely, so a fairly advanced IRST system can counter them. When launching a missile, i.e., when the weapons bay is open, at this moment, the stealth aircraft has an increased RCS making them vulnerable to radar detection. Stealth fighters are designed for the air superiority role. Hence in air-to-air combat, they will always fall prey to advanced enemy aircraft designed for this role. Radars can also detect them with multiple emitters, as in bistatic and multi-static radars.
The Verdict
With advances in electronic warfare (EW) systems, it has become highly efficient to jam enemy radars and surveillance systems. Hence investing in these systems would be the logical thing. These systems depend on the adversary. It all depends on the capabilities of the adversary. If the adversary has foolproof surveillance systems, it makes sense to invest in stealth aircraft. If this is not the case, it is prudent to invest in EW aircraft.
