Stealth Tech: Physics or Electronics?

• Jun 20, 2004

• #1

EngTechno

72

0

I am strongly interested in Stealth Technology. Is this field concerned with Physics? What subject do I need to study for this Technology? Plasma or Electronics?

 

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• Jun 20, 2004

• #2

Gokul43201

Staff Emeritus

Science Advisor

Gold Member

7,220

24

Stealth is achieved mostly through the use of a polymer coating that is a near perfect absober in typical radar wavelengths. Another aspect in stealth design is the geometry of the aircraft (minimizing normal surfaces). And finally there is radar jamming - which, I don't believe gets used by a stealth fighter/bomber - but rather by a different aircraft (like an EA-6B Prowler) when shielding a squadron.

The field is definitely related to physics. I would describe it as interdisciplinary; involving Physics/Electromagnetics, Materials Science and Electronics.

 

• Jun 20, 2004

• #3

Cap'n Refsmmat

11

0

Geometry for one, because shape is important. Things like right angles entirely ruin it. The surface has to be designed to almost always reflect the transmission away from the transmitter/reciever.

 

• Jun 23, 2004

• #4

Ian

88

1

The easiest way to develop stealth technology is to examine the refractive index of the materials used. Radar is an electromagnetic wave and materials will respond to it in the same manner as they do to visible light. The only difference is a change of wavelength between visible and microwave radiation.

 

• Jun 23, 2004

• #5

Njorl

Science Advisor

288

19

There is also the matter of emmissions. These take two forms, thermal, from the engines and exhaust, and electrical, from the on-board electronic systems. Electrical emissions can also be caused by aircraft picking up static charge, but I don't think anyone can use that for detection - yet.

Njorl

 

• Jun 23, 2004

• #6

Gokul43201

Staff Emeritus

Science Advisor

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Oh yes, exhaust temperature control is a big part of the B2's design.

 

• Jun 23, 2004

• #7

Moe

56

0

In stealth aircraft, RAM and RAS are used. The first are Radar-Absorbing Materials, which are polymers that absorb most of the radar energy. RAS are Radar-Absorbing Structures, a honeycomb-type structure that essentially "traps" radar waves.

Next, you try to either use weird angles (F-117) to scatter the radar energy all over the place and to make sure that as little as possible gets back to the emitter. Or you use an approach similar to that of the B-2 and F-22: a small profile, no vertical stabilizers (B-2) or angled ones (F-22).

IR stealth is achieved by IR-absorbing coating and by trying to mask the engine heat signature. You will notice that the engine nozzles in both the B-2 and the F-22 are not on the very rear of the aircraft. That is to give the hot air a chance to mix with the surrounding cooler air and to therefore cool it down. There are also designs which inject a coolant into the airstream after it has left the nozzles to further cool it down.

Jamming is not a form of stealth. If a EA-6 turns on its jammers, everyone will know it is there - they just can't get a lock on it, or talk to each other for that matter. Stealth is akin to walking around at night with a black ninja dress, jamming would be carrying a huge spotlight and shining it in peoples eyes.

Interesting sidenote: The canopy of the F-22s cockpit has a thing layer of gold on it to keep emissions from entering or leaving the cockpit.

 

• Jun 23, 2004

• #8

kuengb

106

0

Talking about gold: I've read once that one of those stealth bombers (don't know their names) is more expensive than its own weight in gold :surprise:

So you can't see them with a radar, hm? No problem, my good old dowsing rod will do the job. No aircraft engineer can beat that

 

• Jun 23, 2004

• #9

russ_watters

Mentor

23,527

10,881

A good book for an engineer's perspective is "Skunk Works" by its director Ben Rich. It cronicles the development of stealth.

Stealth is predominantly based on geometry. The concept came from a Russian scientist who derived from Maxwell's equations a method for calculating the reflectivity of a flat panel. A Lockheed engineer read the paper and developed software for calculating radar cross sections of objects composed entirely of triangles. Hence, the F-117's shape.

The B-2 uses similar software, but more powerful computers means more complex shapes. Plus, the skin in some places is transparent, with faceted surfaces underneath.

Absorption is important, but not anywhere near as important as geometry.

To get into it, electrical engineering, physics, computers, materials, all good fields of study.

 

• Jun 23, 2004

• #10

Moe

56

0

The faceted surfaces would be RAS. By the way, there have been attempts at detecting those stealth aircraft by linking multiple receivers together, each receives a little bit of the scattered radar energy, and then the position of the aircraft is triangulated. It's pretty tricky to do that, though.

Russ: The book you mentioned, for what kind of reader is it intended? That is, would I have to know something special about e.g. engineering to understand it, or is it written for the "general public"?

 

FAQ: Stealth Tech: Physics or Electronics?

What is stealth technology?

Stealth technology is a set of techniques and technologies used to make an object, such as an aircraft or a ship, less visible to radar, infrared, and other detection methods. This allows the object to avoid detection and potentially evade attacks.

Is stealth technology based on physics or electronics?

Stealth technology is based on a combination of both physics and electronics. The principles of physics, such as reflection, absorption, and scattering of waves, are used to design the shape and materials of the object. Electronics, such as radar-absorbent materials and advanced sensors, are also used to enhance the stealth capabilities of the object.

How does stealth technology work?

Stealth technology works by reducing the object's radar cross-section (RCS), which is the measure of how detectable the object is by radar. This is achieved through various methods, such as shaping the object to deflect radar waves away from the source, using radar-absorbent materials to absorb the waves, and using advanced sensors and computer systems to detect and evade incoming threats.

What are the benefits of stealth technology?

The main benefit of stealth technology is its ability to make an object less visible to detection methods, allowing it to operate undetected and potentially avoid attacks. This is particularly important in military applications, where stealth technology can give a significant advantage in combat situations. Additionally, stealth technology can also be used for civilian purposes, such as reducing noise and emissions from aircraft.

What are the limitations of stealth technology?

Although stealth technology provides many benefits, it also has limitations. One limitation is that it is not completely invisible, and can still be detected by certain radar systems. Additionally, the design and materials used for stealth technology can be expensive and may add weight and complexity to the object. Finally, stealth technology is constantly evolving, and as detection methods improve, so must the stealth technology used to counter them.