Eli5: What makes a stealth fighter harder to detect than a regular plane?
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They’re shaped in a way (and made of certain materials) that help deflect radar beams. A normal plane will reflect back a radar signal and be a nice big obvious plane on the radar screen. A stealth place redirects and also absorbs some of the beam, so that only a small amount is returned. From what I remember stealth planes are either invisible or a lot of times looks like the size of a bird on a radar.
Combine that with modern radar/detection/camera systems of its own, so that it can stay way far away from its targets anyways…. I think that’s basically what makes them stealthy!
Stealth aircraft use several different approaches that combine to reduce or nearly eliminate their visible to radar (and to a lesser extent heat-detection systems like on heat-seeking missiles or even just the human eye)
First and most important, is that most stealth aircraft are shaped in such a way that the angles of the plane reflect radar waves *away* from their origin. Remember, radar works by detecting the signals that bounce off the object. If those signals are not going back to a receiver, they’re not being detected. They typically also have special paint or coating that absorbs radar waves and converts them into heat, which again, leads to a smaller signal being received back.
Then they some properties that reduce their visibility to things other than radar. For example, they tend to have engines designed to minimize noise and exhaust heat which makes it harder to hear the planes and harder to detect them by tracking their infrared signatures from the engine exhaust. They also tend to be painted in such a way as to be hard to see with the eye. They typically also have special electronic systems (like radars and targeting systems) that don’t leak electromagnetic waves that could be detected.
In general, the stealthiest aircraft use all of the above, but you can achieve some measure of stealth or at least reduced visibility to radar by using some of the above options.
You have a nerf gun full of unlimited bouncy balls.
Your friend is walking across a field at night towards you.
You pickup your nerf ball gun and spray in a line across the field. When a ball, or a bunch of them, hit your friend they come back towards you. Congratulations, you found your friend.
Now your friend goes stealth. He carries a padded cardboard box, except he points a corner of it towards you, so any balls directed at him bounce off to the sides – or because of the padding just get absorbed.
Stealth planes either deflect or absorb radar “bouncy balls” so that they don’t get sent back to the enemy. It comes down to the design of the plane as well as the materials used as, you can’t have any signal going towards the enemy or they will see you.
Throw a ball at a wall and it is going to come right back to you. Throw a ball at [this thing](https://i.pinimg.com/236x/25/5f/4c/255f4cc45fc642d4fbfa147008c66977.jpg) and there is a very low chance it comes back to you.
Radar requires things to bounce off the plane and come back to you.
Generally speaking detection usually involves one of two methods:
– active (bouncing something off a vehicle and detecting its reflection, such as searchlights, radar, sonar).
– passive (detecting disturbance caused by the vehicle, such as noise or heat or magnetic anomalies)
For stealth craft, radar (for long distance detection) and infra-red (for short distance) are the biggest concerns.
Common techniques for avoiding radar:
– build using radar-absorbent materials
– shaped without any sharp, concave ‘corners’ that reflect a lot
– house the powerplants internally behind a long duct (the fans are typically very big reflectors)
– using serrated edges with a mix of absorbent and non-absorbent materials, so the radar bounces back and forth and eventually loses strength.
– house missiles internally in a weapons bay
Reducing Infra-red can be a bit trickier:
– the shape of the nozzle can reduce the signature (slits better than round nozzles)
– some aircraft have the nozzles above the wing, so the hottest part of the exhaust is hidden from ground detection.
– some aircraft mix cold air in with the exhaust in order to cool it to avoid detection.
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The stealth aircraft are defined to fly at high altitudes, fly fast, and fly quietly, as well as have an odd shape to deflect a radar signal in such a way that it does not return to the source. This is what makes the aircraft so hard to detect through conventional methods.
If you point your flashlight in the dark sky can you see the light when you look up at it? No, because the light needs something to bounce off of and back to you in order for you to see it. Radar works in a similar way. The plane is designed so that the radar bounces in a different direction from where it came from. That way the radar receiving station isn’t getting much of the signal back.
Second way is to reduce/absorb the signal. How much light can you see if you shine the flashlight at a white sheet of paper versus a black sheet of paper? The black sheet is absorbing some of the light, so that is reducing the light bouncing back for you to see. The plane is absorbing or reducing the signal strength.
Stealth aircraft are covered in Radar Absorbent Materials (RAM) that absorbs most radar waves, and the shapes of the aircraft also help deflect radar waves away from the direction they came from, preventing the radar from seeing any waves bouncing back to it. The RAM does most of the work, but not all of it.
The shape of the plane redirects some of the radar energy waves away from the plane but not back towards the radar tracker. The material of the plane coating absorbs some of the radar energy waves so they don’t bounce back towards the radar tracker. If it works well the radar system doesn’t detect that a plane is there. If it does’t work so well the radar tracker registers that there’s an insect or something.
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