Why was the F-117 retired so quickly?(technology.org)
technology.org
Why was the F-117 retired so quickly?
https://www.technology.org/how-and-why/why-was-the-f-117-retired-so-quickly-top-facts/
127 comments
I've always loved the "Sorry we didn't know it wasn't invisible" propaganda poster[0] created by the Serbians after they shot down that F-117.
[0] https://upload.wikimedia.org/wikipedia/commons/c/c0/Serbian_...
[0] https://upload.wikimedia.org/wikipedia/commons/c/c0/Serbian_...
At first i thought it was just the same phrase repeated in multiple languages but then i saw "NATO" near the bottom. The Wikipedia file posting didn't have the translation so i pasted the file into Google translate repeatedly to get each line in its respective language and its very interesting. If anyone knows what
Budanivci or Budjanovci is, i assume it's probably a name.
Croatian - your plane is burning Serbian - Mine is visible but doesn't fall Aircraft waste budanivci Bosnian - WE ALSO HAVE PARTS FROM F - 117A Serbian - Suddenly the earth got in his way Bosnian - Missed the airport in Surčin Ukranian - Dad, types without a hand Serbian - WHAT WILL HAPPEN TO THE WHITE HOUSE? I'M GOING TO LIGHT IT UP Serbian - Last post office budjanovci Serbian - Give me another one....we need to cover the pigsty Serbian - What does a child know what is invisible Croatian - We will fuck NATO, my brother! Serbian - briefly but fucking
Croatian - your plane is burning Serbian - Mine is visible but doesn't fall Aircraft waste budanivci Bosnian - WE ALSO HAVE PARTS FROM F - 117A Serbian - Suddenly the earth got in his way Bosnian - Missed the airport in Surčin Ukranian - Dad, types without a hand Serbian - WHAT WILL HAPPEN TO THE WHITE HOUSE? I'M GOING TO LIGHT IT UP Serbian - Last post office budjanovci Serbian - Give me another one....we need to cover the pigsty Serbian - What does a child know what is invisible Croatian - We will fuck NATO, my brother! Serbian - briefly but fucking
Buđanovci is the village where it was shot down
https://en.wikipedia.org/wiki/Bu%C4%91anovci
https://en.wikipedia.org/wiki/Bu%C4%91anovci
I thought that really only happened because they used the same route repeatedly and because they kept their bomb bay doors open longer than necessary which ruined the stealth?
> “ Because the F-117 is not all that stealthy”
Is that accurate?
I thought the F-117 was still more stealthy than 4th & 5th jets.
https://photo2.tinhte.vn/data/attachment-files/2022/09/61180...
Is that accurate?
I thought the F-117 was still more stealthy than 4th & 5th jets.
https://photo2.tinhte.vn/data/attachment-files/2022/09/61180...
That chart is wrong. You can’t give a single number for RCS as it depends on angle, radar wavelength, and aircraft condition. Generally though the RCS for the B-2 is believed to be the best, followed by the F-22, then the F-35, then the F-117.
F-35 is not very good in dogfight, but it at least can do it. F-117 can not.
That's like faulting a can opener for not slicing pizza well.
Are you sure? Seriously, imagine, you got bad can opener with each bottle. Will you store HUNDREDS of unnecessary things when you have other good quality (F-35 instead of F-117)?
Are you really know, how expensive jet service? What you know about top secret military jet service costs?
Or may be you think, you could just drop F-117 on parking even without guard? Sure, why guard them, when they should guard themselves? ;)
Are you really know, how expensive jet service? What you know about top secret military jet service costs?
Or may be you think, you could just drop F-117 on parking even without guard? Sure, why guard them, when they should guard themselves? ;)
I'm just saying that faulting a F-117 for not being a dog fighter is silly when it was designed to be a bomber.
The real reason to retire the F-117 was because the B-2 could stealthily deliver more bombs anyways and they wanted to free up funding for other projects, not because the F-117 couldn't dog fight. That wasn't its job.
The real reason to retire the F-117 was because the B-2 could stealthily deliver more bombs anyways and they wanted to free up funding for other projects, not because the F-117 couldn't dog fight. That wasn't its job.
Well, I partially agree. But F-117 is too tiny for bomber. It's like top trunk for auto.
BTW, Lockheed offered to create larger variant, but Boeing project chosen.
BTW, Lockheed offered to create larger variant, but Boeing project chosen.
Great post, I knew about the story, but thanks for the detailed explanation.
Great post. More interesting detail than the article.
One simple reason - separate from the less fun possibilities involving defense procurement politics - is that the F117 was a transition technology.
It proved that super low radar signatures were possible.
The design used those big low poly triangles not because it’s optimal (aerodynamically, very much not!) but because of the limits of computer simulation at the time.
There’s a whole fascinating story about how the theory behind low observable was developed by a Soviet scientist, published, ignored there, then implemented here.
But computer technology quickly advanced to where low-poly aircraft made airworthy by brute force were no longer necessary. See the B2 Spirit, also a very special simulation derived shape but streamlined.
It proved that super low radar signatures were possible.
The design used those big low poly triangles not because it’s optimal (aerodynamically, very much not!) but because of the limits of computer simulation at the time.
There’s a whole fascinating story about how the theory behind low observable was developed by a Soviet scientist, published, ignored there, then implemented here.
But computer technology quickly advanced to where low-poly aircraft made airworthy by brute force were no longer necessary. See the B2 Spirit, also a very special simulation derived shape but streamlined.
> but because of the limits of computer simulation at the time
Is this true? I thought the low poly was that a curve always has an area whose norma vector points back to radar, where flat pieces (and their intersections) only do if they're perpendicular to the radar. So, unless you're unlucky enough to have one plate shining pointing back at the radar, the reflection is completely broken up, with the small corners being too small to effectively reflect radar wavelengths back.
Or, maybe I'm just having trouble visualizing a smooth surface geometry that also has few normals back? I naively assumed the "smooth" planes were enabled by better absorption materials, rather than geometry. Maybe a mix?
Is this true? I thought the low poly was that a curve always has an area whose norma vector points back to radar, where flat pieces (and their intersections) only do if they're perpendicular to the radar. So, unless you're unlucky enough to have one plate shining pointing back at the radar, the reflection is completely broken up, with the small corners being too small to effectively reflect radar wavelengths back.
Or, maybe I'm just having trouble visualizing a smooth surface geometry that also has few normals back? I naively assumed the "smooth" planes were enabled by better absorption materials, rather than geometry. Maybe a mix?
> Or, maybe I'm just having trouble visualizing a smooth surface geometry that also has few normals back? I naively assumed the "smooth" planes were enabled by better absorption materials, rather than geometry. Maybe a mix?
You're not wrong. From a head-on perspective, especially from below, you'll find few if any curves. Newer stealth planes look curvier because photographs are often taken from above where the canopy is prominent, and where the top of the body and wings have some curvature. But look more closely. Even from above, the curves you see are usually on the trailing portion of surfaces or facing laterally; the leading edge of the wings on a B-2, F-22, or F-35 are actually flat and triangular, not at all like a typical diagram of an airfoil. This is especially true of the F-22 and F-35--if you look very closely, they're far more angular from more perspectives than the older B-2. The B-2 looks curvier from below, but the flying wing design isn't a coincidence; and I believe the B-2 also relies more heavily on radar absorbing skin than later aircraft, which rely more on simple geometry much like the F-117.
Moreover, beneath the skin of these planes it's widely believed that the framing uses sawtooth and other similar polygonal patterns you'd expect, a mitigation for radar that passes through the skin. And I would think that part of the engineering of these aircraft leverages radar transparent skin in some areas, not just absorbant skin, similar to a nose cone holding a radar.
Here's a really amazing slide presentation on the basics of stealth design: https://understandingairplanes.com/Stealth-Airplane-Design.p... (I first came across that document via an HN post several years ago.)
You're not wrong. From a head-on perspective, especially from below, you'll find few if any curves. Newer stealth planes look curvier because photographs are often taken from above where the canopy is prominent, and where the top of the body and wings have some curvature. But look more closely. Even from above, the curves you see are usually on the trailing portion of surfaces or facing laterally; the leading edge of the wings on a B-2, F-22, or F-35 are actually flat and triangular, not at all like a typical diagram of an airfoil. This is especially true of the F-22 and F-35--if you look very closely, they're far more angular from more perspectives than the older B-2. The B-2 looks curvier from below, but the flying wing design isn't a coincidence; and I believe the B-2 also relies more heavily on radar absorbing skin than later aircraft, which rely more on simple geometry much like the F-117.
Moreover, beneath the skin of these planes it's widely believed that the framing uses sawtooth and other similar polygonal patterns you'd expect, a mitigation for radar that passes through the skin. And I would think that part of the engineering of these aircraft leverages radar transparent skin in some areas, not just absorbant skin, similar to a nose cone holding a radar.
Here's a really amazing slide presentation on the basics of stealth design: https://understandingairplanes.com/Stealth-Airplane-Design.p... (I first came across that document via an HN post several years ago.)
Thanks for the presentation.
At the end there is a list of books by the presenter (who works at Boeing as structural engineer):
- Lockheed Stealth by Bill Sweetman
- America's Stealth Fighers and Bombers by James C. Goodall
- Stealth Technology by J. Jones
- Stealth Warplanes by Dough Richardson
- The Radar Game: Understanding Stealth and Aircraft Survivability by Rebecca Grant
- Skunk Works by Ben R. Rich
And by Bill Sweetman
- Inside the Stealth Bomber
- Joint Strike Figher
- F-22 Raptor
There is also a good playlist on youtube covering some of the topics:
https://www.youtube.com/playlist?list=PLfIy3BUXB3vLu1ZZz9bQb...
- Lockheed Stealth by Bill Sweetman
- America's Stealth Fighers and Bombers by James C. Goodall
- Stealth Technology by J. Jones
- Stealth Warplanes by Dough Richardson
- The Radar Game: Understanding Stealth and Aircraft Survivability by Rebecca Grant
- Skunk Works by Ben R. Rich
And by Bill Sweetman
- Inside the Stealth Bomber
- Joint Strike Figher
- F-22 Raptor
There is also a good playlist on youtube covering some of the topics:
https://www.youtube.com/playlist?list=PLfIy3BUXB3vLu1ZZz9bQb...
That's a great PDf. And in ~20-30 years I'll be really interested to know if the b2 did have active RF countermeasures.
Absolutely true that the faceted shape was due to computational limits at the time. There is a book detailing the development process for the shape of the F-117, but I can't remember the title. Anybody?
Anyway, the basic principle of stealth design is not what people intuitively think. As I recall, it has more to do with refraction along edges than reflection from surfaces. It was originally figured out by some Russian guy. I think that story was also in the book I can't remember.
Anyway, the basic principle of stealth design is not what people intuitively think. As I recall, it has more to do with refraction along edges than reflection from surfaces. It was originally figured out by some Russian guy. I think that story was also in the book I can't remember.
Skunk Works by Ben Rich? Haven't read it yet though so can't confirm.
I've read it and this is the book. It tlis a fascinating read and I recommend it.
Yes. I read it based on a recommendation on HN, and it was very interesting. Not as good as "The Soul of A New Machine", but still quite worthwhile.
The Ben Rich book is good, but the one I was thinking of, which covers technical details of stealth technology, is Peter Westwick (2020) Stealth: The Secret Contest to Invent Invisible Aircraft. It is really very good.
> maybe I'm just having trouble visualizing a smooth surface geometry that also has few normals back?
https://en.wikipedia.org/wiki/Northrop_Grumman_B-2_Spirit
https://en.wikipedia.org/wiki/Northrop_Grumman_B-21_Raider
The interface where the top and bottom meet (ie the only surfaces normal to the horizon, since they intentionally deleted vertical control surfaces) have relatively sharp edges and curvatures.
Curves are okay, as long as you plan them correctly. The tighter the curve the smaller the radar return. After all, the F-117's corners are (in the limit) just curves with a very tight radius.
The other trick is that (when viewed from the top) all the lines along the perimeter are parallel. That means there are only ~4 azimuth angles where the edges are presented 'face on' to an observer. At all other azimuth angles the radar return will glance off the (importantly, singly-curved) outer edge, bouncing the return signal away from the radar.
Presumably they'll plan flight paths such that these four relatively high-observability vectors will "sweep past" known radar installations rapidly, ideally while the plane is making a turn. All the radar sees is a small, extremely brief blip, which could well be discarded as a bogus radar return (either automatically or by human operators).
No insider information of course, just looking at the shape and applying geometric reasoning.
I have vague memories of reading about the coating on F-117. It was supposed to be multiple layers of epoxy paint with suspended ferrous particles, each layer cured under a different magnetic field to align them. To re-coat, the plane would have to be disassembled. The effect they wanted is most likely cancellation, analogous to anti-reflective coatings on glass. Idk.
Furthermore, I have seen pictures of F22 with brown rust stains on panels that should not have any steel in them.
Furthermore, I have seen pictures of F22 with brown rust stains on panels that should not have any steel in them.
Here are some bits about the paint etc. from a War Zone article about sending a retired pre-production model to a museum.
https://www.thedrive.com/the-war-zone/4729/the-toxic-death-p...
https://www.thedrive.com/the-war-zone/4729/the-toxic-death-p...
I memory about this is rusty, but there was A LOT going on with this stealth tech. I vaguely remember color being important, too. The earlier (and stealthier!) designs had a camouflage look rather than black. But this looked "ugly". So they changed it. I think advancements in materials made this moot.
The story on the color is actually simpler. They had put a lot of effort into designing a camouflage pattern for it and there was still some debate over the final design. The project manager from the Pentagon heard about it and said, "This thing is only going to fly at night, right? So just paint it black and be done with it."
When practically bumps up against design dreams lol
You have the advantage of seeing the successor tech. Nothing later of 117 uses the 'big poly' design, with B-2 as an immidiate successor and F-22/35 as a years later one.
There would be always a question why did they chose a flying iron design, but efficency clearly states it's not needed.
There would be always a question why did they chose a flying iron design, but efficency clearly states it's not needed.
For all we know, there could be low poly panels under an RF transparent skin. The "efficiency" could be purely aerodynamic.
I had never considered that the Northrop YB-49 [1] might have ultimately worked if computer simulation had been available at the time.
[1] https://en.wikipedia.org/wiki/Northrop_YB-49
[1] https://en.wikipedia.org/wiki/Northrop_YB-49
Another key requirement would have been computer-aided flight control systems. The only reason the B-2 can remain stable during maneuvers is thanks to its fly-by-wire system that translates the pilot's directions into control surface adjustments that achieve the desired results, and continually adjust those controls faster than the human pilot can react.
The curious may find this wikipedia article a good jumping point down this rabbit hole:
https://en.wikipedia.org/wiki/Relaxed_stability
https://en.wikipedia.org/wiki/Relaxed_stability
My favorite is the Grumman X-29: https://en.wikipedia.org/wiki/Grumman_X-29 (It worked and they built two, I think) but ultimately a dead-end.
Saw these fly over my high school back when I lived in Ohio (close to Wright Pat AFB)
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> The design used those big low poly triangles not because it’s optimal (aerodynamically, very much not!)
It was so bad, they called it The Hopeless Diamond. To keep it in the air instead of dropping like a stone, flight computers had to be developed. Another stepping stone for the B2 which faced similar challenges.
It was so bad, they called it The Hopeless Diamond. To keep it in the air instead of dropping like a stone, flight computers had to be developed. Another stepping stone for the B2 which faced similar challenges.
It’s always confused me, under the radar absorbent material is stuff like engines, cockpits, and other reflective material. I’ve always wondered if under the smooth aerodynamic shape was a polygon frame covered in carbon fiber. That way the polygons could reflect radar away from the more reflective parts.
I've heard this but can't remember the name of the book!
Does anyone know?
Does anyone know?
Skunk Works, by Ben Rich. It's a classic, and the origin of my own fascination with the A-12/SR-71, and the F-117.
Highly recommend reading "Skunk Works: A Personal Memoir of My Years at Lockheed", written by the father of F117, Ben Rich. It detailed the history of creating NightHawk as well as other famous aircrafts like U-2 and BlackBird(A-12 / SR-71). Too bad the book couldn't cover F-22 Raptor as it hasn't been declassified at the time of writing (1996)
To me, the real recognition of their proficiency was learning that SR-71s leak fuel like crazy when they are on the ground... because their body expands from heat during flight.
At first I thought that was incredibly wasteful, then I realized it was actually brilliant, given the circumstances in which the plane was used.
At first I thought that was incredibly wasteful, then I realized it was actually brilliant, given the circumstances in which the plane was used.
Yea, that and the external engine used to start the engines were pretty great ideas to simplify the project and still meet their requirements.
Each of the two Buick V-8s had eight straight exhaust pipes that exited out of the bottom of the AG330. Each engine had a Hydromatic transmission with electric shift, and the two transmissions were coupled together by a 12 inch wide, toothed Gilmer belt.
The pilot told the Crew Chief via intercom "Engage Buicks". The Buick operator pressed "Jet Start", and movement of the Buick throttle (one throttle lever controls both engines) downward engaged the transmissions. . . . The pilot would watch his onboard gauges to confirm minimum oil pressure, fuel pressure, and rising RPM, and then set the jet throttle to idle. At that point 30cc of TEB was injected into the burner cans, a characteristic green flame was emitted, the J58 lit off, accelerated and started to run on its own. The accelerating jet started to unload the Buicks, and when 3,200 rpm was reached, the pilot called "Buicks out", the Crew Chief signaled "cut", the Buick operator hit "Cart Shutdown", the probe fell free passively, and the cart throttle automatically returned to idle.
https://www.thesr71blackbird.com/Aircraft/Engines/starting-t...
The pilot told the Crew Chief via intercom "Engage Buicks". The Buick operator pressed "Jet Start", and movement of the Buick throttle (one throttle lever controls both engines) downward engaged the transmissions. . . . The pilot would watch his onboard gauges to confirm minimum oil pressure, fuel pressure, and rising RPM, and then set the jet throttle to idle. At that point 30cc of TEB was injected into the burner cans, a characteristic green flame was emitted, the J58 lit off, accelerated and started to run on its own. The accelerating jet started to unload the Buicks, and when 3,200 rpm was reached, the pilot called "Buicks out", the Crew Chief signaled "cut", the Buick operator hit "Cart Shutdown", the probe fell free passively, and the cart throttle automatically returned to idle.
https://www.thesr71blackbird.com/Aircraft/Engines/starting-t...
If it’s crazy and it works, it’s not crazy.
Well, every car IC engine is started by another "engine", albeit an electric one, and these days embedded. But then again these IC engines used to be started by an external crank.
So the gist of the idea is not that far fetched.
(Now I'm wondering how the huge Diesel engines on massive boats are being started, I wouldn't be surprised if they were started by a smaller IC engine)
So the gist of the idea is not that far fetched.
(Now I'm wondering how the huge Diesel engines on massive boats are being started, I wouldn't be surprised if they were started by a smaller IC engine)
And still used by some racing cars e.g. F1 has an external (electric) starter, that the mechanic inserts into a hole in the back of the car that goes into the back of the diff -> gearbox -> ICE.
Compressed air usually.
Why is leaking fuel brilliant?
Usually a fuel leak is a problem. It's something that occurs. You have your design, you build it and somewhere in the whole process a problem occurs and there's a fuel leak, usually at high/operating temperature. Maybe the design didn't take into account some temperature expansion, or the materials used were not appropriate, whatever.
But then again, maybe while designing you observe that there's going to be a problem. You do realize that, say, the very different temperatures will inevitably produce too big an expansion for the connecting pipes to be leak-proof while flying, or maybe the expansion will be so big that the material will break when the engine reaches some temperature. So you try to design a solution to that problem. Maybe it would require a new material, which means almost inevitably years of research and a lot of money. Maybe you could design some very specialised connection that can operate at different temperatures and modify its geometry so that it doesn't leak at any temperature; which again may take a lot of time and money in research.
So, here comes the brilliance of the solution: You turn the design around. You define the connections' "normal state" to be the one at high temperature. You design for that, make sure that while in operation, there's no leak, the connections don't overpressure, the fit is right.
But obviously then what will happen is at low temperature the contraction of the material will produce leaks. But you think about it and realise that this only happens at landing/take-off, for the "brief" time that the plane is moving on the ground, which is both a much safer situation and a shorter amount of time. In those circumstances you can afford to have some leaks without it being so much of a problem.
So, it's not so much that the solution is "leaking fuel is brilliant", but that the design acknowledges the inevitability of a leak, and then moves the leak to the moment where its presence is less problematic. So you sacrifice some non-dangerous fuel loss on each mission, while allowing for a better, more secure solution on the moments the plane operates nominally. And all without needing those years/money spent on complex research.
But then again, maybe while designing you observe that there's going to be a problem. You do realize that, say, the very different temperatures will inevitably produce too big an expansion for the connecting pipes to be leak-proof while flying, or maybe the expansion will be so big that the material will break when the engine reaches some temperature. So you try to design a solution to that problem. Maybe it would require a new material, which means almost inevitably years of research and a lot of money. Maybe you could design some very specialised connection that can operate at different temperatures and modify its geometry so that it doesn't leak at any temperature; which again may take a lot of time and money in research.
So, here comes the brilliance of the solution: You turn the design around. You define the connections' "normal state" to be the one at high temperature. You design for that, make sure that while in operation, there's no leak, the connections don't overpressure, the fit is right.
But obviously then what will happen is at low temperature the contraction of the material will produce leaks. But you think about it and realise that this only happens at landing/take-off, for the "brief" time that the plane is moving on the ground, which is both a much safer situation and a shorter amount of time. In those circumstances you can afford to have some leaks without it being so much of a problem.
So, it's not so much that the solution is "leaking fuel is brilliant", but that the design acknowledges the inevitability of a leak, and then moves the leak to the moment where its presence is less problematic. So you sacrifice some non-dangerous fuel loss on each mission, while allowing for a better, more secure solution on the moments the plane operates nominally. And all without needing those years/money spent on complex research.
Secondary factors here are that:
1. There are no separate fuel tanks on the A-12/SR-71. The body of the aircraft is also the fuel tank. If there were internal fuel tanks separate from the body of the aircraft, then there wouldn't be any leaks. But then that would add weight and bulk that they couldn't afford.
2. The fuel they're burning is JP-7, which is so hard to ignite that it will put out a match, or if dumped on a fire, it will put out the fire. You have to get it to much higher temperatures for it to ignite. So, leaks that do happen at low temperatures (on the ground, early in the flight envelope, etc...) just aren't that big of a deal. There's not many things that would be able it ignite the fuel when it leaks at those times.
1. There are no separate fuel tanks on the A-12/SR-71. The body of the aircraft is also the fuel tank. If there were internal fuel tanks separate from the body of the aircraft, then there wouldn't be any leaks. But then that would add weight and bulk that they couldn't afford.
2. The fuel they're burning is JP-7, which is so hard to ignite that it will put out a match, or if dumped on a fire, it will put out the fire. You have to get it to much higher temperatures for it to ignite. So, leaks that do happen at low temperatures (on the ground, early in the flight envelope, etc...) just aren't that big of a deal. There's not many things that would be able it ignite the fuel when it leaks at those times.
Probably because it’s a thinking out of the box solution: fixing the leaks seems the logical and conventional thing to do, but chances are that it would have required trade-offs that made conditions at high speed worse (e.g. more stress on the body.)
I’m totally speculating here.
I’m totally speculating here.
cause leaking fuel costs a few hundred dollars per flight and they don't get a lot of flights. solving the problem "correctly" would probably have taken at least a year or two and probably a couple hundred thousand dollars per plane.
"...given the circumstances in which the plane was used"
I wasn't there but I have the impression that kerosene was not the limiting factor back then. So they solved an engineering problem (body expanding in multiple directions) by declaring, not a problem!
I wasn't there but I have the impression that kerosene was not the limiting factor back then. So they solved an engineering problem (body expanding in multiple directions) by declaring, not a problem!
Because there are no rubber gaskets that can operate at those temperatures, they'd all just melt, so there's literally no way to proper seal them.
My favorite anecdote was him getting a ball-bearing with the same radar cross-section as the F-117, and dropping it on the desk of people who were in the decision making process for buying it. Due to security concerns, he was then banned from carrying the ball-bearings.
I loved how when they were first developing stealth technology the standard procedure was to build a wood model, mount it on a pole, and and check the radar cross section. Eventually it got to the point where the pole had a higher radar cross section than the model plane and they had to spend a lot of time and money developing a more "stealthy" pole.
IIRC they got Northrop to pay for half the cost of developing the stealth pole (since Northrop had a competing stealth design).
I love this book and read it at the same time as reading the book “Voyage” by Stephen Baxter that has some similar sections with teams of people quickly building advanced aerospace projects.
Because of this two books are interwoven in my brain, it’s a weird mashup.
Because of this two books are interwoven in my brain, it’s a weird mashup.
10/10 book. If you are remotely interested in the Cold War or in aircraft, this is a must read.
The actual content, after removing the ChatGPT-style filler:
> Some contemporary stealthy strategic bombers like the famous B-2 are able to remain unnoticed even in the presence of low-frequency radars. But new radar technologies threaten even these powerful stealth bombers. Therefore, the F-117, optimized to defeat high-frequency radars, is no longer relevant in current fights.
> Moreover, it cannot map out threat emitters in real time like its successors F-22 and F-35. It is also not able to survive when it is detected and confronted.
> Some contemporary stealthy strategic bombers like the famous B-2 are able to remain unnoticed even in the presence of low-frequency radars. But new radar technologies threaten even these powerful stealth bombers. Therefore, the F-117, optimized to defeat high-frequency radars, is no longer relevant in current fights.
> Moreover, it cannot map out threat emitters in real time like its successors F-22 and F-35. It is also not able to survive when it is detected and confronted.
+1 on the "hang on I'm reading the output of ChatGPT :/" - it took me until halfway through the article to realize.
Ugh, that's not an easy/low-effort skill to pick up and run autonomously without effort.
Ugh, that's not an easy/low-effort skill to pick up and run autonomously without effort.
If you can't tell then why would you care?
First of all they could tell, they noticed it halfway through not after the fact. I noticed it instantly when I saw an article from a site I'm not familiar with an article on a niche topic with zero timeliness.
Secondly the reason to care is that it's a waste of time. There are an infinite number of stories that sound vaguely interesting enough to click on. Previously there was a sort of filter of "and that someone actually investigated and decided it was indeed interesting enough to write about". That didn't happen here. The article tells you absolutely nothing beyond that it was retired, potentially because "new radar technologies threaten even these powerful stealth bombers. Therefore, the F-117, optimized to defeat high-frequency radars, is no longer relevant in current fights."
Is that even true? I don't know. There's a good chance it is, ChatGPT is right more often than it's wrong. But I'm pretty confident that there probably wasn't any human involved with the expertise necessary to fact check it.
And the bigger problem is that it isn't really interesting, at all. Maybe it could have been if it went into more detail into why and how exactly it stopped being effective at stealth because of modern radar. But it doesn't go into anything like that because it was written by a chatbot which was prompted by a human who only wanted some words they could publish, not any actually useful or interesting information.
Secondly the reason to care is that it's a waste of time. There are an infinite number of stories that sound vaguely interesting enough to click on. Previously there was a sort of filter of "and that someone actually investigated and decided it was indeed interesting enough to write about". That didn't happen here. The article tells you absolutely nothing beyond that it was retired, potentially because "new radar technologies threaten even these powerful stealth bombers. Therefore, the F-117, optimized to defeat high-frequency radars, is no longer relevant in current fights."
Is that even true? I don't know. There's a good chance it is, ChatGPT is right more often than it's wrong. But I'm pretty confident that there probably wasn't any human involved with the expertise necessary to fact check it.
And the bigger problem is that it isn't really interesting, at all. Maybe it could have been if it went into more detail into why and how exactly it stopped being effective at stealth because of modern radar. But it doesn't go into anything like that because it was written by a chatbot which was prompted by a human who only wanted some words they could publish, not any actually useful or interesting information.
The frequency of published medium-length pieces with a low signal to noise ratio (which I generally avoid, whether human-generated or not) does seem to be going up with the proliferation of LLMs.
I could tell that the article was what my English teacher used to call "waffle" - i.e. a lengthy, meandering stream of vague and low-relevance verbiage - a while before I suspected ChatGPT.
It's also wrong, because both F22 and F35 can still be seen by low frequency radars. Probably less, but it's still not a good explanation.
Good topic, decent article, terrible way to answer the question in the title.
Good topic, decent article, terrible way to answer the question in the title.
What are the new radar technologies? Isn't radar ultimately a very simple process?
Improved networking and sensor processing is one big avenue of improvement. Low observable designs typically do the majority of their heavy lifting by 'deflecting' radar beams away from the source. This means distributed systems of transmitters and receivers, networked together with enough compute oompf could potentially do a much better job at detecting and tracking.
At the absolute bleeding edge of radar technology (like... probably decades and decades out) is developing and deploying quantum radar systems (these use entanglement to try to increase signal to noise).
At the absolute bleeding edge of radar technology (like... probably decades and decades out) is developing and deploying quantum radar systems (these use entanglement to try to increase signal to noise).
Bouncing a signal is simple. Making sense of the signal you get back is extremely complicated.
AESA, actively scanned electronic array. Among other things, they're harder to detect and jam than older radars, so aircraft don't know if they've been detected and EW techniques aren't as effective.
https://en.wikipedia.org/wiki/Active_electronically_scanned_...
https://en.wikipedia.org/wiki/Active_electronically_scanned_...
AESA is just the way you form and steer the beam and listen for the return. It doesn't automagically mean your beam is less detectable or harder to jam.
It's the tricks that are easier to deploy with AESA that achieve that - noise-like signal, higher receiver sensitivity allowing for lower emission power, clever signal processing etc.
It's the tricks that are easier to deploy with AESA that achieve that - noise-like signal, higher receiver sensitivity allowing for lower emission power, clever signal processing etc.
God no. The details were more secret than the atom bomb in the 40's and are much more complicated than that today.
Not an expert but I think over the horizon radar is a relatively new-ish tech. Legacy radar is relies on line of sight to to your target.
That's like saying "aren't cameras a very simple process" when comparing Explorer 6 and the JWST.
That entire article could be summed up in a simple sentence. They advancement of low frequency radar made it obsolete.
I suppose it is just me, but really can't stand when a simple answer is drug out to a massive, article like this.
I suppose it is just me, but really can't stand when a simple answer is drug out to a massive, article like this.
This article is from a content mill and is the product of chat GPT.
I don't agree that the article is drawn out or massive at all. It has 5 short sections, each only a few sentences, and each section answers a question relevant to the topic: what is the F-117, why was it made, how did it work, when did we stop using it, and why did we stop using it. The questions are up front, and the answers are fairly concise.
Another question might be why no other nation was allowed to acquire them. Lots of advanced fighters get exported. Advanced guided missile radar evading aircraft less so.
The comment about having to use low level attack craft to destroy specific radar types so the f117 can evade the other types is telling: "invisible to radar" was a bit hype-y
The comment about having to use low level attack craft to destroy specific radar types so the f117 can evade the other types is telling: "invisible to radar" was a bit hype-y
It's hard to absorb the long-wavelength radar used by large, stationary units, but they can be taken out with cruise missiles early in the conflict. Stealth works very well against short-wavelength radar used by hard to target SAM missile launchers that are still around after the big radars are dead. So they don't really mind as much that they can be seen by the type of radar that doesn't shoot at them.
It was effectively invisible to the radars that existed when it was made.
High frequency radars are more accurate than low frequency, nobody used low frequency at the time. They're also smaller, I don't think you could use a low frequency radar with a missile's seeker. Low frequency is good enough to throw up flak, though--and that's how the one that was lost got hit.
It was also vulnerable to bistatic radar--but I don't believe a bistatic radar could even have been built back then.
It was basically a one-trick wonder that got counterdesigned.
High frequency radars are more accurate than low frequency, nobody used low frequency at the time. They're also smaller, I don't think you could use a low frequency radar with a missile's seeker. Low frequency is good enough to throw up flak, though--and that's how the one that was lost got hit.
It was also vulnerable to bistatic radar--but I don't believe a bistatic radar could even have been built back then.
It was basically a one-trick wonder that got counterdesigned.
> nobody used low frequency at the time
I don't think this is true. Low frequency was and continues to be the best option for early warning and over-the-horizon use cases.
> good enough to throw up flak, though - and that's how the one that was lost got hit
It was hit with a 1960s era SAM after running the same route again and again. https://en.m.wikipedia.org/wiki/1999_F-117A_shootdown
I don't think this is true. Low frequency was and continues to be the best option for early warning and over-the-horizon use cases.
> good enough to throw up flak, though - and that's how the one that was lost got hit
It was hit with a 1960s era SAM after running the same route again and again. https://en.m.wikipedia.org/wiki/1999_F-117A_shootdown
There are basically 3 different eras of the F-117.
First, during the Cold War... the F-117 was one of America's silver bullets. Don't wanna risk anything getting leaked out.
In the 90s to early 2000's... who on earth would buy an F-117? Especially amongst nations friendly to the USA. With the exception of maybe Israel, no US aligned nation had a reason to have a low observable strike aircraft.
In the twilight of its career - well the JSF/F-35 existed. Why buy the old, single purpose, first generation stealth aircraft when F-35s should be just around the corner...
First, during the Cold War... the F-117 was one of America's silver bullets. Don't wanna risk anything getting leaked out.
In the 90s to early 2000's... who on earth would buy an F-117? Especially amongst nations friendly to the USA. With the exception of maybe Israel, no US aligned nation had a reason to have a low observable strike aircraft.
In the twilight of its career - well the JSF/F-35 existed. Why buy the old, single purpose, first generation stealth aircraft when F-35s should be just around the corner...
> Another question might be why no other nation was allowed to acquire them. Lots of advanced fighters get exported.
My understanding of this is that there's a threshold of "really good but not too good" that is a bit arbitrary. The F-117 and the follow-on F-22 Raptor both crossed over the line into "way too good" territory and couldn't be exported. While it's pretty cool having aircraft that are so advanced that no other country on earth can own them but your own, the net result ends up being... you don't have anyone to share the NRE costs with, which drives the unit cost and spare parts costs up like crazy.
My understanding of this is that there's a threshold of "really good but not too good" that is a bit arbitrary. The F-117 and the follow-on F-22 Raptor both crossed over the line into "way too good" territory and couldn't be exported. While it's pretty cool having aircraft that are so advanced that no other country on earth can own them but your own, the net result ends up being... you don't have anyone to share the NRE costs with, which drives the unit cost and spare parts costs up like crazy.
It's funny to go back to early 90s conspiracy/UFO culture and its talk of seeing "black triangles" flying around area 51 or other secret military sites. Turns out it was just people seeing testing of the F117 or B2 and not alien technology.
Knew a dude who operated a bulldozer on contract for the army in the early 60s. He'd get on a bus in Nevada and get taken to "don't ask where." He was given a big bulldozer; which he would use to pile up triangle shaped piles of dirt beside a long, long runway. Then a few days later he'd be back, doing the same thing, the piles he'd made last week mysteriously gone.
Later he found that he was building sound baffles for incoming U2 flights; and the turbulence blew his work away after only a couple landings. Said it was good money and helped him get started. He was eventually one of the bigger military surplus dealers in the USA.
Later he found that he was building sound baffles for incoming U2 flights; and the turbulence blew his work away after only a couple landings. Said it was good money and helped him get started. He was eventually one of the bigger military surplus dealers in the USA.
That seems off. The U-2 used the same engine as the Boeing 707 and then later the B52 back then. And I can't imagine that the engine are really all that powered up on landings since the U-2 acted a lot like a glider when landing.
Well, every U2 that lands needs to take off again, so maybe it was related to takeoff more than landing...
Sure but B52s have 8 of those engines and they don't need baffles and/or aren't destroying them on a weekly basis. That story could be true but it seems unlikely that it would be U2 planes that are causing enough turbulence to destroy piled up mounds of dirt by the runways.
I dunno if the individual was correct; he may have guessed or been told; or may have made the entire story up for all i know. But i doubt that last.
I figured it was landing turbulence; them things come in hot.
I figured it was landing turbulence; them things come in hot.
Not really, the F117 became public knowledge during desert storm in '91.
Most of what the public calls triangle UFOs is air-air-refueling practice
Most of what the public calls triangle UFOs is air-air-refueling practice
Exactly, the shock and awe strategy used during the first gulf war involved a lot of video footage of high precision weaponry being used to hit all sorts of targets and long briefings by generals talking about how awesome they were. The F117 deployment to Iraq was big news and widely reported and the US Airforce basically couldn't shut up talking about just how awesome these things were.
> The F117 deployment to Iraq was big news and widely reported and the US Airforce basically couldn't shut up talking about just how awesome these things were.
Desert Storm, sure.
12 years later for Iraqi Freedom? Nope. We were in the sandbox low key to kickstart Saddam's farewell/get-rekt party and back at Holloman much quicker than most other air expeditionary squadrons.
Desert Storm, sure.
12 years later for Iraqi Freedom? Nope. We were in the sandbox low key to kickstart Saddam's farewell/get-rekt party and back at Holloman much quicker than most other air expeditionary squadrons.
I seem to remember (could be wrong) that it was first publicised after getting used in Panama a couple of years earlier.
I dunno, most of the Black Triangle sightings were in the US Northeast, were MUCH larger and super slow. This is my anecdotal memory from Art Bell, local news and the such.
I saw one in the Pittsburgh area ca 2014-15. Slow, quiet, but too big to be a glider or Hindenburg style gas balloon.
It was freaky.
It was freaky.
If you search on youtube, you can see that some F-117s are still flying. For example: https://www.youtube.com/watch?v=9UUOJBBNfZY&ab_channel=Youtu...
Yes. It currently looks like USAF is using F-117s in testing/training roles. Some warzone articles:
https://www.thedrive.com/the-war-zone/f-117-nighthawks-caugh...
https://www.thedrive.com/the-war-zone/retired-f-117-nighthaw...
https://www.thedrive.com/the-war-zone/f-117-nighthawks-caugh...
https://www.thedrive.com/the-war-zone/retired-f-117-nighthaw...
"This airplane was a secret project of the U.S. Army" it says.
Really.
Really.
So secret, they convinced the air force to believe it was their project.
I mean, in the grand scheme of things, the air force was born from the army air corp. So abstracted enough I guess there is some truth to that.
I chuckled when I read that part.
Was this written by ChatGPT? It's incredibly puffy, keeps repeating itself, and ultimately says very little.
99% yes. The other 1% is that maybe they used a different chatbot.
It was retired over Yugoslavia https://theaviationgeekclub.com/an-in-depth-analysis-of-how-...
The pictured cockpit, from the Air Force museum, looks like a prototype or a very early model.
The real cockpit had at least two multifunction displays.
Modern digital avionics is the heart of this precision bombing platform, increasing mission effectiveness and decreasing pilot workload. The F-117 cockpit is equipped with Heads up display (HUD), twin color multifunction display indicators, and a digital moving map system.
https://www.f117sfa.org/about-the-f117
A cockpit picture: https://images.squarespace-cdn.com/content/v1/5a36dd6f8a02c7...
The real cockpit had at least two multifunction displays.
Modern digital avionics is the heart of this precision bombing platform, increasing mission effectiveness and decreasing pilot workload. The F-117 cockpit is equipped with Heads up display (HUD), twin color multifunction display indicators, and a digital moving map system.
https://www.f117sfa.org/about-the-f117
A cockpit picture: https://images.squarespace-cdn.com/content/v1/5a36dd6f8a02c7...
Correct.
The larger display unit in the center was the primary human interface for IRADS video fed from FLIR/DLIR turrets.
The larger display unit in the center was the primary human interface for IRADS video fed from FLIR/DLIR turrets.
Because it was security by obscurity, and the moment it was shot down over Serbia, it became useless.
When I was in air defense school in the mid-90s, we would regularly lock onto these during training. It might be invisible on radar, but it was just like any other plane to short range infrared and ultraviolet shadow seeking weapons like the Stinger and Avenger.
Only one F-117 was shot down and it is an interesting story made into a documentary movie.
https://www.military.com/military-life/how-air-force-pilot-b...
https://www.military.com/military-life/how-air-force-pilot-b...
I think it’s worth remembering that achieving stealth isn’t about the aircraft exclusively. It’s about the entire mission profile. Route, time of day, defeat of certain radars by means other than stealth, terrain considerations, altitude and approach.
despite the "F" designation it wasn't ever a multi-role fighter (ignoring it's er... trasnsport role in Executive Decision) and nowadays most combat aitcraft can't afford to be so specialised
Technology moved on and the F-117 can't keep its pilots alive once its stealth is defeated.
Which is pretty much what TFA says.
because it got slapped out of the air by a far less potent force??
USA should send some mothballed F117 to Ukraine after their pilots get experience with F16, it costs us nothing and would help them where they are struggling the most (missing airpower).
I don't think _anything_ about flying the F117 would transfer over from the F16 other than "the stick at your legs moves the ailerons". They are completely different aircraft and the F117 as I understand is notorious for being difficult to fly and control. Not to mention the stealth advantage has been defeated by modern AA systems like Russia's S400 SAM, so you're really just getting a heavy and difficult to fly aircraft that only carries two 500 lb bombs. There's much better stuff that should be sent before you start scrounging up mothballed F117s.
F117 supposedly shares many components with F16, more than you'd think. F16 is extremely vulnerable to GBAD and won't be able to safely fly close to the front lines. Ukraine is struggling because it cannot strike Russian supply lines safely like USA did to Iraq in 1991. It is unproven that an S400 could defeat a well-operated F117 -- We cannot say the same for something like F16.
I think it is questionable ethically to "lead Ukraine on" in terms offering military support, if that support is intended to only be just enough to manage a bloody and protracted stalemate. We should either pressure them to settle, or genuinely offer enough weapons to help them succeed (pushing Russia to accept some kind of "'conditional' defeat 'with honor'"). Letting both countries bleed themselves out like its WW1 should not be an option.
I think it is questionable ethically to "lead Ukraine on" in terms offering military support, if that support is intended to only be just enough to manage a bloody and protracted stalemate. We should either pressure them to settle, or genuinely offer enough weapons to help them succeed (pushing Russia to accept some kind of "'conditional' defeat 'with honor'"). Letting both countries bleed themselves out like its WW1 should not be an option.
If a bloody stalemate were the objective, that would not be questionable. It would be immoral, neigh evil.
However. There are many less nefarious reasons possible.
Sending more (capable) equipment costs money. It decreases your own readiness. It increases the possibility of proliferation. It risks the russians getting hold of it for analysis. It definitely has proven to irritate the Russians, risking escalation. More capable equipment requires more training and logistics that Ukraine does not have.
Note that for nations other than Russia and Ukraine, this conflict is strategic but not (yet) existential. We have not, and politically cannot, converted our economic output to the war effort. This lack of political and societal will explains why we're not fully comitted.
However. There are many less nefarious reasons possible.
Sending more (capable) equipment costs money. It decreases your own readiness. It increases the possibility of proliferation. It risks the russians getting hold of it for analysis. It definitely has proven to irritate the Russians, risking escalation. More capable equipment requires more training and logistics that Ukraine does not have.
Note that for nations other than Russia and Ukraine, this conflict is strategic but not (yet) existential. We have not, and politically cannot, converted our economic output to the war effort. This lack of political and societal will explains why we're not fully comitted.
Your points are valid. But its also valid to say there may be a narrow path towards stopping bloodshed sooner rather than later. The only reason Russia is still fighting in Ukraine is because they believe they have a chance to outlast Western social willpower. Russia would be more willing to accept defeat if NATO gave more open support to Ukraine. Increasing carrot (sanctions relief, oil deals, Crimea compromise, etc.) and stick (supplying more advanced weapons, NATO membership) at the same time might end the war sooner and stop pointless death.
True, we should arm them with nukes too, they're missing that capability as well.
You forgot the carrier battle group.
In 1999 over Serbia, one F-117 was shot down and supposedly another one was damaged. It was shot down by a Russian S-125, which is a missile system from the early sixties.
The Serb air defense officer that shot it down says that the F-117 was detected by his radar at 23km. He developed the tactic of moving his radar and missile launcher regularly, and then only turning on the radar for a short time and moving again. He says that the F-117s going into Serbia were following the same flight path over and over and he figured out a good time and place to turn on the radar.
In the book Skunk Works, there's some detail about the mission planning that goes on for F-117 missions. They have software that, given the positions and types of radars, will find the lowest risk path in to the target. This is also referenced here: [1]
Knowing all of this, you can surmise that the F-117 is detectible out to 20-30km (depending on angle), but they simply route the planes to go around the radars. Presumably if a new radar pops up, the F-117 can detect this (or be cued by an AWACS or EW plane) and fly another way, or turn around. However, if the radar pops up suddenly, it may be too late.
Once the effectiveness of this tactic was proven, the value of the F-117 went down a lot. Then you start looking at the other deficiencies of the plane. It has a small bomb load, not very long range, no supersonic capability, limited sensors, no air to air capability. If the plane is invincible, these are forgivable, but if not, then maybe not.
Anyhow despite all of that, they still fly the F-117 in retirement for training and testing purposes, and they still get sighted in the air and on ramps periodically.