Stealth in Airplanes and Ships

By pjain      Published Sept. 11, 2020, 10:05 p.m. in blog Geo-Politics   

Stealth BPR for Military Defenses

Can Modify planes to enhance stealth

See Israel improves US F-35 Stealth Fighter below.

Stealth technology and Physics 101

What is Stealth technology

  • Stealth is not one magic tech, rather a mantra of design that incorporates low observability.

Of all the potential threats faced by combat aircraft, detection and tracking by radar pose the most risk. Radar, infrared, and optical detection all rely on the bouncing of electromagnetic radiation of an object in order to gather information from it.

However, radar differs in that the source of the reflected radiation is actively emitted from the observer. With passive methods of detection, the target’s own emissions or ambient light are used.

While detecting an aircraft provides a warning, in order to defend against it, it must be tracked. Tracking is the determining of a target position, velocity, and heading from a reflected signal.

While some defense weapons can track optically, infrared tracking is the predominant method for close range air defense due to its ability to see the heat of an aircraft through the atmosphere. Infrared tracking works by using an infrared sensor similar to a camera to "look" for the highly contrasting signature of hot jet exhaust gases and the warm aircraft body, against the ambient air temperature.

Why? Radar eliminates Airplanes surprise and allows target with Anti-Air defenses

The goal of radar stealth is to both mask an aircraft from being detected, tracked and fired upon from a distance. This is known as beyond visual range engagement.

Active vs Passive Sensors

Sonar is radar for underground.

How Battlefield integrated C4 and 360-view systems can beat stealth

However, F-35 was designed for a single "target" AA batteries.

The Eye-in-the-sky systems can detect profiles of missiles and jets long before ground based radar can. Different POVs have different intersections. Put together the reliability goes from 50=70% under 30 seconds for local radar batteries to many minutes of warning and nearly 90% accuracy!

Advances in Anti-Stealth systems

But there already exist methods for detecting stealth fighters eg long-range infrared sensors, electromagnetic sensors, and low bandwidth radars (though all have significant limitations), and more exotic technologies such as quantum radar are also under development.

Long-range infrared sensors

Electromagnetic sensors

Low bandwidth radars

quantum radar

Visual targeting limited - night time raids - use light-out to counter

Most Anti-Air defenses historically relied on visual range engagement. By doing night time raids and ops, the higher tech side using night vision gear gets a huge advantage.

Low to Ground - down to trees - IR targetting

As distances close, radar-based engagements may transition into IR based targeting either low to the ground, or among adversarial aircraft within a dogfight.

Stealth METRICS - Radar cross-section metric - RCS

Early attempts at stealth were based on observations of radar on existing designs. It was discovered early on that the shape of an aircraft determined its visibility to radar, its radar cross-section or RCS.

Edge Reflectance not Size is Key to Radar Visibility - Pyotr Ufimtsev

Soviet mathematician and physicist Pyotr Ufimtsev published a paper titled Method of Edge Waves in the Physical Theory of Diffraction in the journal of the Moscow Institute for Radio Engineering. Ufimtsev’s conclusion was that the strength of the radar return from an object is related to its edge configuration, not its size. Astoundingly, the Soviet administration considered his work to have no significant military or economic value, allowing to be published internationally.

Radar evolves also - 2020 BPR

In 2020 most military airborne radars, including those found in radar-based anti-air missiles, operate in the 5 cm - 1 cm wavelength microwave range as it provides a good compromise between range, resolution and antenna sizing.

Timeline of Stealth and Stealth Majors Globally

WWII UK first used Radar to detect German Planes

The first military use of radar began around the start of world war 2. One of the more notable uses was in the air defense of England. By 1939 a chain of radar stations protected the East and South coast provided early warning to incoming aircraft.

Lockheed ECHO-1 incorporates Ufimtsev's theories

As Ufimtsev's time Lockheed’s elite Skunk Works design team was working on a stealth proof-of-concept demonstrator called Have Blue. The engineering team struggled with predicting stealthiness as the program they created to analyze radar cross-section called ECHO-1 failed to produce accurate results. Denys Overholser, a stealth engineer on the project had read Ufimtsev’s paper, realizing that he had created the mathematical theory and tools to do a finite analysis of radar reflection. Ufimtsev's work was incorporated into ECHO-1. The iconic early stealth looks was a direct byproduct of the computational limit of computers of the time, which limited ECHO-1’s ability to perform calculations on curved surfaces.

Northrop Tacit Blue

Northrop began working on a technical demonstrator of its own, know as Tacit Blue. Tacit Blue attempted to demonstrate a series of then advanced technologies including forms of stealth that employed curved surfaces. During the late 1970s, momentum was building for the development of a deep penetrating stealth bomber.

1979 Advanced Tactical Bomber program Aurora

By 1979, the highly secretive Advanced Tactical Bomber program was started, under the code name "Aurora".

F-117 Nighthawk - 1991 Desert Storm infiltrated Baghdad's air defenses

On January 17, 1991, at 2:30AM, the opening attack of Operation Desert Storm was set in motion. Tasked with crippling Iraq’s command and control, shipborne Tomahawk and B-52 launched AGM-86 cruise missiles were employed to infiltrate targets within Bagdad. Alongside this initial inrush of deep striking assets, was a new class of weapon. This attack was the first public debut of a stealth aircraft facing off against one of the largest air defense networks in the region. The Lockheed F-117 Nighthawk, the first stealth strike platform, were among the first sorties to enter the heavily defended airspace of Baghdad.

Stealth in Other US helicopters and Ships

With the success and dominance of the US stealth programs, the technology has worked its way into other applications such as the canceled Comanche RAH-66 reconnaissance helicopter, the Sea Shadow, the USS Zumwalt.

1990s US F-22 Raptor stealth fighter - fast, expensive

It still reigns as the top air-superiority fighter in service: it is fast, highly maneuverable and extremely stealthy. However, the Raptor was less optimized for ground-attack roles and deemed too expensive to build and operate to serve as a replacement of the Pentagon’s large inventory of fourth-generation fighters—so production was cut to just 180 aircraft, 120 of which serve in operational units.

US F-35 Stealth Fighter

Stealth is USP

Israel thinks the F-35’s low radar cross section will be “good for five to ten years” before adversaries develop countermeasures.

Lockheed F-35 Development a $2T incomplete

The F-35 Lightning II Joint Strike Fighter is estimated to be the most expensive weapons system in human history, based on its projected lifetime cost of $1.5 trillion dollars ($406 billion for the aircraft, the rest in lifetime operating costs). On top of this there would be lot more cost overruns.

It is a critical weapons system for USA, Nato and allies. Different variants of the F-35 are prepared to equip the Air Force, Navy and Marines through most of the twenty-first century, and the type is also slated to serve in the air forces or navies of Australia, Belgium, Denmark, Israel, Italy, Japan, the Netherlands, Norway, South Korea and Turkey—with more countries likely to join the list.

The Pentagon was persuaded to pay for “concurrent” production of F-35s before it had been developed into a fully operational prototype; today Lockheed is shipping non-feature-complete F-35s, which will need to be expensively upgraded later when new components and systems are finally ready.

Is the USA scared of F-35 being profiled by S-300/S-400?

After Russia placed its S-300, Israel which had earlier dominated mideast airspace, has flown very few missions, as their air force is left down in Syria.

Israel F-35I improves US F-35 Stealth Fighter

Israel had chosen the F-35 type to replace its fleet of over 320 F-16s.

References

Modification of Existing planes


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