How stealth planes actually work

I suspect that 5th generation fighters are antennas, something like a log-periodic antenna which often are in the shape of a delta wing, etc.

The extended range of radar capability on 5th generation fighters can only come from power-increase or a larger antenna; so right there is our first big clue.

The "skin effect" is a physics phenomenon that deals with conductors and can explain the phenomenon that turns a plane's skin into a conductor (antenna) that receives radar waves and turns it into AC current and thereby doesn't reflect it back to the transmitter.

I'm looking for evidences and one of those would be found in the power-plant and electrical systems. The stated capability of the F-35 is a radar range ~100km, the Su-57 is ~200km. Which makes sense as the Su-57 is a bigger plane and thus a "bigger antenna" than the F-35. But I'm hoping to find a better clue in the electrical systems such as the F-35 to demonstrate that the AESA radars are not big enough nor powerful enough to reach the stated 100km ranges.

www.lockheedmartin.com...

Another clue: I suspect that the "air-duct heat exchangers" are fake parts, created to give the maintenance personnel something to do to hide the truth. It only makes sense such a product would exist just to throw-off 2 to 6 year enlisted nobodies with limited to no meaningful background checks and next to no top secret clearances...

Of course. Why didn't we just think to put a few heat exchangers into the air-intakes of the jet engine and solve ALL OUR PROBLEMS of cooling? Why didn't anyone think of that for 50 years of jet flight?

Instead we been using this insanely cumbersome cooling system....

www.mdpi.com...

Well the answer becomes more apparent when you turn the skin of your aircraft into a conductor you can just convert all waste heat into power through thermocouples and bleed it off through the skin of the aircraft. Still looking into this idea.

But perhaps the heat exchangers in the air ducts work, but doesn't look like it. Their mass is very insignificant.

a reply to: DarthTrader

I think the stealth comes from deflection of radar waves instead of reflection.
The coatings also absorb some radar waves but it’s probably like the way a rubber compound absorbs sound waves.

originally posted by: Bluntone22
a reply to: DarthTrader

I think the stealth comes from deflection of radar waves instead of reflection.
The coatings also absorb some radar waves but it’s probably like the way a rubber compound absorbs sound waves.

This is largely proven false but is a little known fact. The F-35 for instance has no special deflective surfaces and anyone can duplicate deflective surfaces. There are some 'stealthy' characteristics of this such as internal weapons bays, boxy afterburners, and angled rudders. But if this was the only feature then Somalia could build stealth aircraft just as soon as they could put together a wooden airplane.

Structural characteristics of radar reflections have been well known for 70 years. They didn't suddenly get discovered in the 1980s.

There are Radar Absorbent Materials that were discovered in the 80s, I actually am almost certain that boro-silicates were among the first because those are heat shields for space craft and it was quickly realized spacecraft are hard to detect by radar. There's a whole study about it in the 1980s for the STS-Orbiter which led me to the contractor that built the STS-Orbiter's heat shields.

This is how I got off on this tangent because that same contractor also builds heat sinks for F-35 Avionics. A front company I'm sure. No one needs Space Shuttle tile heat sinks for cpus....but the borosilicate RAM composites would be useful.

But, those are not difficult to make. So what makes a 5th gen aircraft is even more significant now than before? Likely the changes by geometry and materials wasn't enough and so was largely ignored up through 4th gen. The suspicion with conductor-skin-effects is way more complex than either of the prior and could explain the extended radar ranges at 8GHz - 15GHz.

a reply to: DarthTrader

They've gotten away from deflection and into shaping and absorption instead. The skin of the current fifth gen aircraft absorbs most of the EM energy and keeps it trapped between the internal structure and skin of the aircraft, which increases the heat of the aircraft, requiring more efficient heat exchangers and heat dissipation. The F-117 used the ability to deflect radar because it was easier to model at the time.

The AN/APG-68 pulse doppler radar used in the F-16 has a 184 mile range, with a 65 mile range against a 5m2 target. The AN/APG-81 has a range of around 80-90 miles against a 1m2 target.

a reply to: DarthTrader

I just watched a video of the F-35 and the military are calling it the Ferrari class with a price tag of $100 Million and are also saying they need an every day cheaper model, so I'm not too sure where stealth fighters will be going in the near future after hearing that.

a reply to: DarthTrader

The main way they work is to reflect the radar waves in any direction other than back to the radar station. This is mainly accomplished by having no 90 degree angles. Also, as mentioned above, no external weapons or protrusions.

The second way is adorbant paint containing magnetite. This was covered on Myth Busters.

The heat exchangers and fire bricks found in the exhaust have nothing to do with the radar signature. Those are for thermal detection protection, it protects them from heat seaking missiles and inferred targeting. Also the exhaust ports are usually above the aircraft and not on the back to hide the heat from the ground.

a reply to: quintessentone

The F-35A Lot 15-17 runs between $70.2M-$69.9M, the F-35B runs $80.9M-$78.3M, and the F-35C $90M-$89.3M. The Air Force is looking at getting something that makes sense to use against low risk targets. One of the things that was insane about Iraq and Afghanistan was using B-52s and F-35s against pickup trucks driving in the open. That puts a lot of wear and tear on airframes, and they may be tied up in maintenance when you really need them.

originally posted by: Zaphod58
a reply to: quintessentone

The F-35A Lot 15-17 runs between $70.2M-$69.9M, the F-35B runs $80.9M-$78.3M, and the F-35C $90M-$89.3M. The Air Force is looking at getting something that makes sense to use against low risk targets. One of the things that was insane about Iraq and Afghanistan was using B-52s and F-35s against pickup trucks driving in the open. That puts a lot of wear and tear on airframes, and they may be tied up in maintenance when you really need them.

WTH?

a reply to: quintessentone

The cost has been dropping with each lot. That price covers Lot 15, Lot 16, and Lot 17. So Lot 15 starts with the higher price, and Lot 17 is the lower price. Lot 14 ran $77.9M, $101.3M, and $94.4M, and covered Lot 12-14, with 478 aircraft. It was thought the cost would go back up with Lot 15, but they were able to keep them down. Lot 15-17 will cover 398 aircraft.

originally posted by: Zaphod58
a reply to: quintessentone

The cost has been dropping with each lot. That price covers Lot 15, Lot 16, and Lot 17. So Lot 15 starts with the higher price, and Lot 17 is the lower price. Lot 14 ran $77.9M, $101.3M, and $94.4M, and covered Lot 12-14, with 478 aircraft. It was thought the cost would go back up with Lot 15, but they were able to keep them down. Lot 15-17 will cover 398 aircraft.

I was just reading that Canada will by buying 88 F-35 planes by 2032 and I am also reading that Canada will be dependent on expensive software upgrades and other needs of the aircraft from the U.S. Is that true, are they American made? Is this how the price can be made more affordable there, by charging premium $ to other countries?

Instead, Pugliese argues, the real reason Canada is buying these U.S.-built F-35s is because of pressure from the United States, where a large part of its economy is devoted to building weapons. Even more, F-35s give the U.S. influence over allies because countries like Canada will become completely dependent on the Americans for expensive software upgrades and the like for our fleet of aircraft.

www.peacequest.ca...

a reply to: quintessentone

The fact that they're being sold internationally is why the cost is coming down as much as it has. There are something like 890 F-35s currently flying worldwide. The US had approximately 450 of those in April of last year. They're currently assembled at Fort Worth, which is the main location, Nagoya Japan, and Cameri Italy. Similar to Fort Worth, parts are built at various subcontractors worldwide, and shipped to one of those three locations. European partners generally have their first aircraft built in the US, and sent to Arizona, and then receive them from Cameri. Cameri also provides depot level maintenance for European partners.

Australia, Korea, and the UK have their aircraft built in Texas, and then flown from there to their home bases, sometimes using US tankers to support them, other times using their own tankers. Australia, Korea, and Japan trained a cadre of instructor pilots and ground support personnel in Arizona, before moving their aircraft from there to their home countries. Currently Norway, the Netherlands, Italy, Denmark, and the US all train pilots in Arizona. Singapore, when they buy their B models, will move to Arkansas or Michigan for training. The UK trains their pilots in South Carolina, with a Marine training unit based in Beaufort, SC. Several new buyers will probably end up in Arizona at least for initial training.

The Canadian aircraft will be bought from Fort Worth, and probably come to Arizona for a year or so until they have their training cadre and infrastructure ready. Then they'll move them back to Canada for their training program.

One of the deals that goes with the program is that for higher tier partners, they get a portion of the build contract. Canada was going to buy the aircraft back in 2015, and has been a Tier I partner from early on, so they get a lot of contracts to build parts for the final airframe. Australia, Canada, Denmark, Italy, Netherlands, Norway, and the UK are the international partners that get the biggest contracts to build portions of the aircraft. Israel, Japan, Republic of Korea, Poland, Singapore and Belgium are Foreign Military Sales partners. There are several new FMS partners that are in negotiations to buy aircraft, that should complete negotiations this year.

I was under the impression that the stealth aspect was derived by the sharp angular surfaces of the aircraft. Only the knife-edge facing the radar would reflect back to the source, which would be a very small signal in relation to the size of the aircraft. The broader surfaces of the aircraft would deflect the radar away from the source, not back to it. That as opposed to a rounded surface that reflects in all directions, the biggest radar profile possible - except for a flying wall...

a reply to: Vroomfondel

That works for frontal aspect stealth, which the F-22 and F-35 are optimized for. For side and other angles, the aircraft tends to trap most of the EM energy, allowing a small amount to get back to the T/R antenna, meaning there's a very small signature to see.

May be a stupid thought, but I remember when stealth plane where first declassified. They said a stealth plane could reduce the cross-sectional area of plane to the size of a large bird….this was the 1st thought that popped into my head, Ok couldn’t I just reprogram a radar to look for large birds flying at mach 2…. yeah, said it was stupid.

a reply to: tbrooks123

Because that's not how it works. Radar systems automatically screen out certain things as noise. At longer ranges a return the size of most stealth aircraft would appear to be noise on the screen. Once it gets closer and the return gets more solid then it can be tracked, but at long range it would just appear to be clutter. If you programmed your radar to track all small returns it would be overwhelmed pretty quickly.

a reply to: Zaphod58

I hadn't considered that. Thank you. You really know your stuff.

a reply to: Vroomfondel

You can see it in the head on shots of the F-22 and F-35. The intakes look straight, but you can see the edges at an angle. That also limits the energy between the intakes and fuselage on the F-22. The F-35 blends the intake into the fuselage, so there's no gap between the two for the energy to get into.

Also why skin preparation is paramount.Any ripple or misaligned panel,fastener adds to the signal return.