Toxn

So, Sherman vs Panther is a topic that has been chewed over on this forum until only gristle remains. I accordingly have very little to add except to urge the newer members to dig into some of our older threads.
 
In terms of chronological progression vs what hindsight tells us - as @Sturgeon has stated, a T-44/T-54 was entirely within the state of the art in 1939. If aircraft seem to have more quickly arrived at a local optimum, it's partly a function of more resources being poured into them than tanks*, partly a function of the relative utility of outdated models^, and partly a function of different operational and strategic tradeoffs.
 
Tanks are rigidly constrained by fuel supply lines, bridge sizing, tunnel width and train gauges. The result is that you want to get along with the smallest, lightest, most mobile vehicle you can until such time as it isn't tenable any more. With aircraft, the major limitation of runways only kicks in at the very frontline, and accordingly puts hard constraints only on shorter-ranged types such as interceptors and tactical support aircraft. Even then, this mostly bites around the point where jet aircraft become common and landing speeds start to balloon.
 
 
*Resources put into tank vs. aircraft production in WW2 are uniformly almost impossible to directly quantify given wildly fluctuating budgets, the different strategic resources needed by each, the inaccuracies of stated prices, and the fact that all the services kept their own accounts. On the Nazi side of things, wild swings in allocation were frequent but the luftwaffe nearly always ended up with the lion's share of resources (especially scarce resources such as aluminium). As for the Army, only around 20% of their budget went into tanks. The production figures of all combatant nations reflect this: around two aircraft were produced for every tank.
 
 
^An outdated tank can still provide valuable frontline service, while an outdated fighter or bomber is dead weight.

So, Sherman vs Panther is a topic that has been chewed over on this forum until only gristle remains. I accordingly have very little to add except to urge the newer members to dig into some of our older threads.
 
In terms of chronological progression vs what hindsight tells us - as @Sturgeon has stated, a T-44/T-54 was entirely within the state of the art in 1939. If aircraft seem to have more quickly arrived at a local optimum, it's partly a function of more resources being poured into them than tanks*, partly a function of the relative utility of outdated models^, and partly a function of different operational and strategic tradeoffs.
 
Tanks are rigidly constrained by fuel supply lines, bridge sizing, tunnel width and train gauges. The result is that you want to get along with the smallest, lightest, most mobile vehicle you can until such time as it isn't tenable any more. With aircraft, the major limitation of runways only kicks in at the very frontline, and accordingly puts hard constraints only on shorter-ranged types such as interceptors and tactical support aircraft. Even then, this mostly bites around the point where jet aircraft become common and landing speeds start to balloon.
 
 
*Resources put into tank vs. aircraft production in WW2 are uniformly almost impossible to directly quantify given wildly fluctuating budgets, the different strategic resources needed by each, the inaccuracies of stated prices, and the fact that all the services kept their own accounts. On the Nazi side of things, wild swings in allocation were frequent but the luftwaffe nearly always ended up with the lion's share of resources (especially scarce resources such as aluminium). As for the Army, only around 20% of their budget went into tanks. The production figures of all combatant nations reflect this: around two aircraft were produced for every tank.
 
 
^An outdated tank can still provide valuable frontline service, while an outdated fighter or bomber is dead weight.

There were many more fighter programs than tank programs, many of them producing dogs that never went into service. Of the ones that went into service, most were a disappointment in some way. Of the few that weren't, only one or two were outstanding. This gives you a good idea of the numbers involved: around 240 types used or tested, including foreign types, trainers, utility aircraft etc. Of those, maybe half were used in any great numbers in service. Of that 100-ish aircraft, perhaps two dozen rose above the level of mediocre. And of that two dozen, a handful are considered superlative in their class.
 
Aircraft design is very fiddly, and requires a mix of easily-ascertained factors (power-to-weight ratio, wing loading, armament etc.), hard-to-ascertain factors (top speed, turn times in various configurations, landing speeds) and factors which defied empirical modelling and could only be found by experiment (stability, stall characteristics, maintenance and service niggles, random engine/landing gear/aerodynamic bugs etc).
 
Making a good aircraft in WW2 was as much alchemy as science, and resulted in a lot of dead test pilots. Tanks were actually comparatively easier to design, and accordingly got designed by lesser talents on lower budgets (see, again, the example of British tank building in WW2, which was the product of a bare handful of second-tier engineers). Even today, the best mechanical engineers are mostly doing aviation and aerospace. 
 
 

So, Sherman vs Panther is a topic that has been chewed over on this forum until only gristle remains. I accordingly have very little to add except to urge the newer members to dig into some of our older threads.
 
In terms of chronological progression vs what hindsight tells us - as @Sturgeon has stated, a T-44/T-54 was entirely within the state of the art in 1939. If aircraft seem to have more quickly arrived at a local optimum, it's partly a function of more resources being poured into them than tanks*, partly a function of the relative utility of outdated models^, and partly a function of different operational and strategic tradeoffs.
 
Tanks are rigidly constrained by fuel supply lines, bridge sizing, tunnel width and train gauges. The result is that you want to get along with the smallest, lightest, most mobile vehicle you can until such time as it isn't tenable any more. With aircraft, the major limitation of runways only kicks in at the very frontline, and accordingly puts hard constraints only on shorter-ranged types such as interceptors and tactical support aircraft. Even then, this mostly bites around the point where jet aircraft become common and landing speeds start to balloon.
 
 
*Resources put into tank vs. aircraft production in WW2 are uniformly almost impossible to directly quantify given wildly fluctuating budgets, the different strategic resources needed by each, the inaccuracies of stated prices, and the fact that all the services kept their own accounts. On the Nazi side of things, wild swings in allocation were frequent but the luftwaffe nearly always ended up with the lion's share of resources (especially scarce resources such as aluminium). As for the Army, only around 20% of their budget went into tanks. The production figures of all combatant nations reflect this: around two aircraft were produced for every tank.
 
 
^An outdated tank can still provide valuable frontline service, while an outdated fighter or bomber is dead weight.

So, Sherman vs Panther is a topic that has been chewed over on this forum until only gristle remains. I accordingly have very little to add except to urge the newer members to dig into some of our older threads.
 
In terms of chronological progression vs what hindsight tells us - as @Sturgeon has stated, a T-44/T-54 was entirely within the state of the art in 1939. If aircraft seem to have more quickly arrived at a local optimum, it's partly a function of more resources being poured into them than tanks*, partly a function of the relative utility of outdated models^, and partly a function of different operational and strategic tradeoffs.
 
Tanks are rigidly constrained by fuel supply lines, bridge sizing, tunnel width and train gauges. The result is that you want to get along with the smallest, lightest, most mobile vehicle you can until such time as it isn't tenable any more. With aircraft, the major limitation of runways only kicks in at the very frontline, and accordingly puts hard constraints only on shorter-ranged types such as interceptors and tactical support aircraft. Even then, this mostly bites around the point where jet aircraft become common and landing speeds start to balloon.
 
 
*Resources put into tank vs. aircraft production in WW2 are uniformly almost impossible to directly quantify given wildly fluctuating budgets, the different strategic resources needed by each, the inaccuracies of stated prices, and the fact that all the services kept their own accounts. On the Nazi side of things, wild swings in allocation were frequent but the luftwaffe nearly always ended up with the lion's share of resources (especially scarce resources such as aluminium). As for the Army, only around 20% of their budget went into tanks. The production figures of all combatant nations reflect this: around two aircraft were produced for every tank.
 
 
^An outdated tank can still provide valuable frontline service, while an outdated fighter or bomber is dead weight.

So, Sherman vs Panther is a topic that has been chewed over on this forum until only gristle remains. I accordingly have very little to add except to urge the newer members to dig into some of our older threads.
 
In terms of chronological progression vs what hindsight tells us - as @Sturgeon has stated, a T-44/T-54 was entirely within the state of the art in 1939. If aircraft seem to have more quickly arrived at a local optimum, it's partly a function of more resources being poured into them than tanks*, partly a function of the relative utility of outdated models^, and partly a function of different operational and strategic tradeoffs.
 
Tanks are rigidly constrained by fuel supply lines, bridge sizing, tunnel width and train gauges. The result is that you want to get along with the smallest, lightest, most mobile vehicle you can until such time as it isn't tenable any more. With aircraft, the major limitation of runways only kicks in at the very frontline, and accordingly puts hard constraints only on shorter-ranged types such as interceptors and tactical support aircraft. Even then, this mostly bites around the point where jet aircraft become common and landing speeds start to balloon.
 
 
*Resources put into tank vs. aircraft production in WW2 are uniformly almost impossible to directly quantify given wildly fluctuating budgets, the different strategic resources needed by each, the inaccuracies of stated prices, and the fact that all the services kept their own accounts. On the Nazi side of things, wild swings in allocation were frequent but the luftwaffe nearly always ended up with the lion's share of resources (especially scarce resources such as aluminium). As for the Army, only around 20% of their budget went into tanks. The production figures of all combatant nations reflect this: around two aircraft were produced for every tank.
 
 
^An outdated tank can still provide valuable frontline service, while an outdated fighter or bomber is dead weight.

There were many more fighter programs than tank programs, many of them producing dogs that never went into service. Of the ones that went into service, most were a disappointment in some way. Of the few that weren't, only one or two were outstanding. This gives you a good idea of the numbers involved: around 240 types used or tested, including foreign types, trainers, utility aircraft etc. Of those, maybe half were used in any great numbers in service. Of that 100-ish aircraft, perhaps two dozen rose above the level of mediocre. And of that two dozen, a handful are considered superlative in their class.
 
Aircraft design is very fiddly, and requires a mix of easily-ascertained factors (power-to-weight ratio, wing loading, armament etc.), hard-to-ascertain factors (top speed, turn times in various configurations, landing speeds) and factors which defied empirical modelling and could only be found by experiment (stability, stall characteristics, maintenance and service niggles, random engine/landing gear/aerodynamic bugs etc).
 
Making a good aircraft in WW2 was as much alchemy as science, and resulted in a lot of dead test pilots. Tanks were actually comparatively easier to design, and accordingly got designed by lesser talents on lower budgets (see, again, the example of British tank building in WW2, which was the product of a bare handful of second-tier engineers). Even today, the best mechanical engineers are mostly doing aviation and aerospace. 
 
 

There were many more fighter programs than tank programs, many of them producing dogs that never went into service. Of the ones that went into service, most were a disappointment in some way. Of the few that weren't, only one or two were outstanding. This gives you a good idea of the numbers involved: around 240 types used or tested, including foreign types, trainers, utility aircraft etc. Of those, maybe half were used in any great numbers in service. Of that 100-ish aircraft, perhaps two dozen rose above the level of mediocre. And of that two dozen, a handful are considered superlative in their class.
 
Aircraft design is very fiddly, and requires a mix of easily-ascertained factors (power-to-weight ratio, wing loading, armament etc.), hard-to-ascertain factors (top speed, turn times in various configurations, landing speeds) and factors which defied empirical modelling and could only be found by experiment (stability, stall characteristics, maintenance and service niggles, random engine/landing gear/aerodynamic bugs etc).
 
Making a good aircraft in WW2 was as much alchemy as science, and resulted in a lot of dead test pilots. Tanks were actually comparatively easier to design, and accordingly got designed by lesser talents on lower budgets (see, again, the example of British tank building in WW2, which was the product of a bare handful of second-tier engineers). Even today, the best mechanical engineers are mostly doing aviation and aerospace. 
 
 

There were many more fighter programs than tank programs, many of them producing dogs that never went into service. Of the ones that went into service, most were a disappointment in some way. Of the few that weren't, only one or two were outstanding. This gives you a good idea of the numbers involved: around 240 types used or tested, including foreign types, trainers, utility aircraft etc. Of those, maybe half were used in any great numbers in service. Of that 100-ish aircraft, perhaps two dozen rose above the level of mediocre. And of that two dozen, a handful are considered superlative in their class.
 
Aircraft design is very fiddly, and requires a mix of easily-ascertained factors (power-to-weight ratio, wing loading, armament etc.), hard-to-ascertain factors (top speed, turn times in various configurations, landing speeds) and factors which defied empirical modelling and could only be found by experiment (stability, stall characteristics, maintenance and service niggles, random engine/landing gear/aerodynamic bugs etc).
 
Making a good aircraft in WW2 was as much alchemy as science, and resulted in a lot of dead test pilots. Tanks were actually comparatively easier to design, and accordingly got designed by lesser talents on lower budgets (see, again, the example of British tank building in WW2, which was the product of a bare handful of second-tier engineers). Even today, the best mechanical engineers are mostly doing aviation and aerospace. 
 
 

For all the people who want to reward the creator of this video: go get in on the comment dogpile and drive that engagement metric. It's classic YouTube tier and therefore very much good for light entertainment.

Late to this party, but...
 
you're telling us that not only can Americans not do English, Scottish, Australian or South African accents, they can't even do American accents?

Simple solution: simply turn it around for close range flamethrowing action!
 
"Close range flamethrowing action!" is a trademark of the stupid ideas corporation. Warning: flamethrowing has been shown to result in a number of medical issues including: first degree burns, second degree burns, third degree burns, hair loss, skin loss, ignition of subcutaneous fat, asphyxia, uncontrolled bowel movements, cataracts and death. Flamethrowing should only be done in a carefully controlled environment and under adult supervision. Use at own risk.

I'm on the discord and quizzed them about it a few months ago. I couldn't get a straight answer out of them on how they wanted to implement the cartridge/shell designer.
 
We'll just have to see how it plays out I guess.

Presumably step in as replacement marines, same as their last go-around in the pacific.

Presumably step in as replacement marines, same as their last go-around in the pacific.

Yeah, inter-service stuff is generally crazy when seen from the outside, but perfectly sensible and in line with incentives from the inside. And it gets worse the more politically powerful each branch is (witness Imperial Japan).

1. Introduction
 
Stealth is one of those buzz-words that everyone knows. Stealth makes aircraft invisible to radar, allowing a stealth plane to sneak up and punch other aircraft or SAM sites with impunity. Stealth is widely acknowledged as one of the most fundamental technologies that all new combat aircraft need to have. Stealth is also, like SH's old friend NERA, mostly completely misunderstood. This thread will attempt to change that, at least a little.
 
HUGE DISCLAIMER: I know, at best, the basics of what is essentially one of the darkest arts in an already black magic-heavy field (radio and radar engineering). I'll be relying heavily on others to correct my obvious mistakes, but this is and will be the lies-to-children version of the field, as told by another child. Still, given the state of knowledge out there, it's probably better than nothing.
 
2. The most basic basics
 
Okay, you ask, what is stealth then if we're all misunderstanding it? Here I think that the best analogy is that stealth is like camouflage, but for aliens. Camouflage famously entails the 5 (sometimes expanded to 7 with speed and spacing) S's: Shape, Shine, Shadow, Silhouette and Sound. Each operates on somewhat different principles, and can be more or less important in different scenarios, but are united in terms of how human senses work. We are pattern-finding creatures with passive senses, so anything that breaks up visual or auditory patterns, blends one into the background, or limits the amount of noise or reflected light one gives off will make you harder for another human to spot.
 
Radar, however, is generally not passive. Instead, a radar set sends out a beam of electromagnetic energy and looks for an echo. There's a huge amount of complexity in how this can be done (what frequency to use, how to generate and send the beam, how to track the returns and so on), but that's radar at it's most basic. So, like camouflage, ways to avoid radar will be united in trying to trick or defeat this basic mechanism. These principles are, roughly: Absorption, Redirection, Scattering and Emissions. Finally, and just to complete a fun acronym, there's also the side issue of radio-related Shenanigans. Taken together, these measures can significantly reduce how easy an aircraft is for a radar to "see" from certain angles.
 
Absorption is simple in concept: if something eats up the radar waves before it can get reflected, then the receiver doesn't get to pick up a signal and the plane doesn't get found. There's a whole realm of sneaky material science that goes into this, but from my understanding the two most common techniques currently being used are non-metallic structural components (which can be more or less transparent to radar) and foams or paints with nanomaterials in them (the famous grey stealth paint job generally being a weather coating instead of the magic material itself). These can be used in all sorts of clever ways: for instance, by making the forward edge of your wing out of radar transparent composite and then packing the area behind it with cones made out of radar-absorbing foam. Absorption can't make a non-stealthy design stealthy, however. It's more of a "cut 10% off our already-low radar return" sort of strategy.
 
Redirection is one of the single biggest reasons why stealth aircraft have their characteristic look. Generally the principle here is to make as many surfaces on the aircraft as parallel as possible, in order to direct the majority of your return to one or two places rather than scattering it all over the sky. Since the most common place you don't want returns to come back to is directly to the front, this also means that swept wings and tails are a must. It's also why flat bottoms are preferred: if someone is looking at your aircraft from below, then a flat bottom is the one shape guaranteed not to provide a good return until you are right above them.
 
The major enemy of this approach is the dreaded corner reflector, which is where any right-angled surface will reflect a return straight back to it's source. This is why stealth aircraft all have angled fuselages, hard chines and cranked tailplanes, and also why even things like landing gear hatches and bomb bay doors end up with saw-tooth profiles (note: not 90-degree saw teeth if you can help it, because corner reflector). The other major enemy of this approach is aerodynamics, which inherently prefers rounded frontal profiles that are great at reflecting returns back along an entire wing or fuselage segment. So stealth aircraft also tend to have aerodynamic features (sharp-nosed, flat-bottomed airfoil profiles, for instance) that make them a bastard to fly.
 
Scattering: if you're doomed to reflect something in an unwanted direction, then it helps to make the surface convex in order to disperse the return. This is seen in the shallow, curved fuselage profiles of stealthy aircraft which, along with their beaky fronts and hard chines, gives them a sort of alien bird quality. It's also really useful when designing air intakes for the engines you've sensibly buried inside the fuselage (seriously, the front of a jet engine is like a disco ball for creating noticeable radar returns): an S-shaped intake reflects about half as much energy as a straight intake with a similar profile.
 
Emissions are more or less self-explanatory: if you're trying to hide in the dark, then don't bring a flashlight with you. This means no big radio sources or old-school radar sets that a receiver can easily pick up on. I've heard that modern AESA radars are harder to spot for {electronic black magic} reasons, but the principle still stands.
 
Shenanigans are what you resort to in the corner cases where one or the other approaches described above are not possible. These usually make use of unintuitive electromagnetic wave-specific physics like half-wave resonance. The intake screens on the F117, for instance, seem to be sized so that the radar wave "sees" it as a solid surface and bounces off while still allowing at least a trickle of air in to feed the engines. These tricks tend to be fiddly, however, and can go very wrong when faced with radar systems that use frequencies much higher or lower than the ones that they were designed to counter.
 
3. Artists are dumb and wrong
 
So, having learned the barest minimum about how stealth works, let's point and laugh at the mistakes of artists who ape the form of stealth without understanding the content. Note: it's now almost impossible to grab high-resolution images off of websites, so you'll just have to google these things if you want to see them in any sort of level of detail.
 
Example 1: the F-19 from model kits in the late 80s
 
A fictional stealth plane from the time where people could be forgiven for not knowing a damn thing about stealth. The top-mounted air intake and engines are a good idea, but the rounded wings/fuselage profile and anhedral wingtips look like a great way to get returns from every direction. 5/10 for effort at a time when nobody knew what stealth really was.
 
Example 2: F/A-37 Talon from the movie Stealth
 
Considering that the damn movie is called "Stealth", the Talon is a remarkable example of a bunch of artists googling stealth aircraft and then adding enough greebles so that the result is neither stealthy nor much of an aircraft. It has intakes everywhere, a bunch of curves but few parallel lines, a swing-wing setup that I can only imagine puts a bunch of nooks and crannies into the airframe that reflect well, random greebles off at right angles and on and on. 0/10, the aircraft plays Incubus when it's angry and is therefore canonically a moody teenager.
 
Example 3: XA-20 Razorback from Tom Clancy's giant, throbbing brain
 
It's an F-20 that's inexplicably been converted into a CAS aircraft (presumably because, in the dark future of 2020, transaircraft rights are now government policy). That idiocy aside, it's more or less fine. Turns out that when you crib directly off of someone else's work you won't fuck things up too badly.

Having had a look at the performance of the rounds, it looks like the propellant loads would be quite different for each round. The 60mm needs around 1.9dm3 of case volume for the propellant, the 76mm around 4.3dm3 and the 105mm around 7.1dm3.
 
This means less than you'd think in terms of the space that the rounds take up, though, since volume scales cubically. As a toy example: a conservatively bottle-necked case for the 60mm (1/3 larger base than tube diameter) would have to be something like at least ~450mm long, an equivalent case for the 76mm would be ~630mm long, and the 105mm would be ~600mm long.
 
The ease of handling of a round is more or less a function of the case length and weight (with weight being one of those factors that becomes exponentially more of a hassle as it increases). So I'd say that, within a certain floor of effectiveness and ceiling of round mass and size, your operational requirements will probably determine where on the graph of size/weight and effectiveness you land. For instance: the 25% jump in penetration performance from the 60mm to the 76mm at the cost of a 40% increase in case length is a decent trade-off if stowed ammunition and rate of fire is worth trading. As is the 30% jump from the 76mm to the 105mm (at the cost of something like a 70% increase in weight), if you need the extra effectiveness against more modern armour.
 
Again; I'm getting the impression that small-bore APFSDS slingers show up more in second and third-tier armies because those are the forces where the floor of effectiveness is lowest. Zapping T-55s and T-62s instead of T-64s and T-72s just gives you a lot more leeway when it comes to choosing what other trade-offs are worth it. 

Next full comp, which will be no earlier than next year, will be a strike fighter competition.

Thanks, that's a decent find.
 
Edit: this one of theirs might be even better as an intro:
 
 
And this one explains the issue of detection range not scaling linearly with RCS, as well as some of the other, more fiddly aspects of reducing cross-section:
 

1. Introduction
 
Stealth is one of those buzz-words that everyone knows. Stealth makes aircraft invisible to radar, allowing a stealth plane to sneak up and punch other aircraft or SAM sites with impunity. Stealth is widely acknowledged as one of the most fundamental technologies that all new combat aircraft need to have. Stealth is also, like SH's old friend NERA, mostly completely misunderstood. This thread will attempt to change that, at least a little.
 
HUGE DISCLAIMER: I know, at best, the basics of what is essentially one of the darkest arts in an already black magic-heavy field (radio and radar engineering). I'll be relying heavily on others to correct my obvious mistakes, but this is and will be the lies-to-children version of the field, as told by another child. Still, given the state of knowledge out there, it's probably better than nothing.
 
2. The most basic basics
 
Okay, you ask, what is stealth then if we're all misunderstanding it? Here I think that the best analogy is that stealth is like camouflage, but for aliens. Camouflage famously entails the 5 (sometimes expanded to 7 with speed and spacing) S's: Shape, Shine, Shadow, Silhouette and Sound. Each operates on somewhat different principles, and can be more or less important in different scenarios, but are united in terms of how human senses work. We are pattern-finding creatures with passive senses, so anything that breaks up visual or auditory patterns, blends one into the background, or limits the amount of noise or reflected light one gives off will make you harder for another human to spot.
 
Radar, however, is generally not passive. Instead, a radar set sends out a beam of electromagnetic energy and looks for an echo. There's a huge amount of complexity in how this can be done (what frequency to use, how to generate and send the beam, how to track the returns and so on), but that's radar at it's most basic. So, like camouflage, ways to avoid radar will be united in trying to trick or defeat this basic mechanism. These principles are, roughly: Absorption, Redirection, Scattering and Emissions. Finally, and just to complete a fun acronym, there's also the side issue of radio-related Shenanigans. Taken together, these measures can significantly reduce how easy an aircraft is for a radar to "see" from certain angles.
 
Absorption is simple in concept: if something eats up the radar waves before it can get reflected, then the receiver doesn't get to pick up a signal and the plane doesn't get found. There's a whole realm of sneaky material science that goes into this, but from my understanding the two most common techniques currently being used are non-metallic structural components (which can be more or less transparent to radar) and foams or paints with nanomaterials in them (the famous grey stealth paint job generally being a weather coating instead of the magic material itself). These can be used in all sorts of clever ways: for instance, by making the forward edge of your wing out of radar transparent composite and then packing the area behind it with cones made out of radar-absorbing foam. Absorption can't make a non-stealthy design stealthy, however. It's more of a "cut 10% off our already-low radar return" sort of strategy.
 
Redirection is one of the single biggest reasons why stealth aircraft have their characteristic look. Generally the principle here is to make as many surfaces on the aircraft as parallel as possible, in order to direct the majority of your return to one or two places rather than scattering it all over the sky. Since the most common place you don't want returns to come back to is directly to the front, this also means that swept wings and tails are a must. It's also why flat bottoms are preferred: if someone is looking at your aircraft from below, then a flat bottom is the one shape guaranteed not to provide a good return until you are right above them.
 
The major enemy of this approach is the dreaded corner reflector, which is where any right-angled surface will reflect a return straight back to it's source. This is why stealth aircraft all have angled fuselages, hard chines and cranked tailplanes, and also why even things like landing gear hatches and bomb bay doors end up with saw-tooth profiles (note: not 90-degree saw teeth if you can help it, because corner reflector). The other major enemy of this approach is aerodynamics, which inherently prefers rounded frontal profiles that are great at reflecting returns back along an entire wing or fuselage segment. So stealth aircraft also tend to have aerodynamic features (sharp-nosed, flat-bottomed airfoil profiles, for instance) that make them a bastard to fly.
 
Scattering: if you're doomed to reflect something in an unwanted direction, then it helps to make the surface convex in order to disperse the return. This is seen in the shallow, curved fuselage profiles of stealthy aircraft which, along with their beaky fronts and hard chines, gives them a sort of alien bird quality. It's also really useful when designing air intakes for the engines you've sensibly buried inside the fuselage (seriously, the front of a jet engine is like a disco ball for creating noticeable radar returns): an S-shaped intake reflects about half as much energy as a straight intake with a similar profile.
 
Emissions are more or less self-explanatory: if you're trying to hide in the dark, then don't bring a flashlight with you. This means no big radio sources or old-school radar sets that a receiver can easily pick up on. I've heard that modern AESA radars are harder to spot for {electronic black magic} reasons, but the principle still stands.
 
Shenanigans are what you resort to in the corner cases where one or the other approaches described above are not possible. These usually make use of unintuitive electromagnetic wave-specific physics like half-wave resonance. The intake screens on the F117, for instance, seem to be sized so that the radar wave "sees" it as a solid surface and bounces off while still allowing at least a trickle of air in to feed the engines. These tricks tend to be fiddly, however, and can go very wrong when faced with radar systems that use frequencies much higher or lower than the ones that they were designed to counter.
 
3. Artists are dumb and wrong
 
So, having learned the barest minimum about how stealth works, let's point and laugh at the mistakes of artists who ape the form of stealth without understanding the content. Note: it's now almost impossible to grab high-resolution images off of websites, so you'll just have to google these things if you want to see them in any sort of level of detail.
 
Example 1: the F-19 from model kits in the late 80s
 
A fictional stealth plane from the time where people could be forgiven for not knowing a damn thing about stealth. The top-mounted air intake and engines are a good idea, but the rounded wings/fuselage profile and anhedral wingtips look like a great way to get returns from every direction. 5/10 for effort at a time when nobody knew what stealth really was.
 
Example 2: F/A-37 Talon from the movie Stealth
 
Considering that the damn movie is called "Stealth", the Talon is a remarkable example of a bunch of artists googling stealth aircraft and then adding enough greebles so that the result is neither stealthy nor much of an aircraft. It has intakes everywhere, a bunch of curves but few parallel lines, a swing-wing setup that I can only imagine puts a bunch of nooks and crannies into the airframe that reflect well, random greebles off at right angles and on and on. 0/10, the aircraft plays Incubus when it's angry and is therefore canonically a moody teenager.
 
Example 3: XA-20 Razorback from Tom Clancy's giant, throbbing brain
 
It's an F-20 that's inexplicably been converted into a CAS aircraft (presumably because, in the dark future of 2020, transaircraft rights are now government policy). That idiocy aside, it's more or less fine. Turns out that when you crib directly off of someone else's work you won't fuck things up too badly.