Stealth aircraft

[8] Stealth is a combination of passive low observable (LO) features and active emitters such as low-probability-of-intercept radars, radios and laser designators.

Early stealth aircraft were designed with a focus on minimal radar cross section (RCS) rather than aerodynamic performance.

Newer stealth aircraft, like the F-22, F-35 and the Su-57, have performance characteristics that meet or exceed those of current front-line jet fighters due to advances in other technologies such as flight control systems, engines, airframe construction and materials.

[3][4] The high level of computerization and large amount of electronic equipment found inside stealth aircraft are often claimed to make them vulnerable to passive detection.

This is highly unlikely and certainly systems such as Tamara and Kolchuga, which are often described as counter-stealth radars, are not designed to detect stray electromagnetic fields of this type.

As soon as weapons bay doors are opened, the plane's RCS will be multiplied and even older generation radar systems will be able to locate the stealth aircraft.

[citation needed] New stealth aircraft designs such as the F-22 and F-35 can open their bays, release munitions and return to stealthy flight in less than a second.

Such aircraft as the F-22 Raptor and F-35 Lightning II Joint Strike Fighter can also carry additional weapons and fuel on hardpoints below their wings.

[26] In December 2007, SAAB researchers revealed details for a system called Associative Aperture Synthesis Radar (AASR) that would employ a large array of inexpensive and redundant transmitters and receivers that could detect targets when they directly pass between the receivers/transmitters and create a shadow.

That the array could contain a large amount of inexpensive equipment could potentially offer some "protection" against attacks by expensive anti-radiation missiles (ARMs).

Some analysts claim Infra-red search and track systems (IRSTs) can be deployed against stealth aircraft, because any aircraft surface heats up due to air friction and with a two channel IRST is a CO2 (4.3 μm absorption maxima) detection possible, through difference comparing between the low and high channel.

This has prompted Nizhny Novgorod Research Institute of Radio Engineering (NNIIRT) to develop VHF AESAs such as the NEBO SVU, which is capable of performing target acquisition for Surface-to-air missile batteries.

The Dutch company Thales Nederland, formerly known as Holland Signaal, developed a naval phased-array radar called SMART-L, which is operated at L Band and has counter-stealth.

During World War I, the Germans experimented with the use of Cellon (Cellulose acetate), a transparent covering material, in an attempt to reduce the visibility of military aircraft.

Single examples of the Fokker E.III Eindecker fighter monoplane, the Albatros C.I two-seat observation biplane, and the Linke-Hofmann R.I prototype heavy bomber were covered with Cellon.

The material was also found to be quickly degraded both by sunlight and in-flight temperature changes, so the attempt to make transparent aircraft was not proceeded with.

[31] In 1916, the British modified a small SS class airship for the purpose of night-time aerial reconnaissance over German lines on the Western Front.

Fitted with a silenced engine and a black gas bag, the craft was both invisible and inaudible from the ground, but several night-time flights over German-held territory produced little useful intelligence, and the idea was dropped.

[32] Nearly three decades later, the Horten Ho 229 flying wing fighter-bomber was developed in Nazi Germany during the last years of World War II.

In 1983, its designer Reimar Horten claimed that he planned to add charcoal to the adhesive layers of the plywood skin of the production model to render it invisible to radar.

Tests were performed in 2008 by the Northrop Grumman Corporation to establish if the aircraft's shape would have avoided detection by top-end HF-band, 20–30 MHz primary signals of Britain's Chain Home early warning radar, if the aircraft was traveling at high speed (approximately 550 mph (890 km/h)) at extremely low altitude – 50–100 feet (15–30 m).

[citation needed] The F-22 puts a focus on air superiority, with supercruise, high thrust-to-weight ratio, integrated avionics, and of course, stealth.

[citation needed] Stealth aircraft were used in the 2011 military intervention in Libya, where B-2 Spirits dropped 40 bombs on a Libyan airfield with concentrated air defenses in support of the UN no-fly zone.

[48] Stealth aircraft will continue to play a valuable role in air combat with the United States using the F-22 Raptor, B-2 Spirit, and the F-35 Lightning II to perform a variety of operations.

[52] In 2018, a report surfaced noting that Israeli F-35I stealth fighters conducted a number of missions in Syria and even infiltrated Iranian airspace without detection.

[40] In May 2018, Major General Amikam Norkin of IAF reported that Israeli Air Force F-35I stealth fighters carried out the first-ever F-35 strike in combat over Syria.