Because that’s more mass out board of the wings which means it has a bigger moment of inertia. Moment of inertia is the resistance to something rotating or spinning. By moving the mass towards the center, you reduce the moment of inertia and for the same amount of angular momentum you would spin faster.
This is the equivalent to a figure skater pulling their arms in to make them spin faster. For a fighter yet you want high angular rates so you want to minimize your moment of inertia wherever possible.
Makes sense. What about putting 2 engines on the wings but also near the main body fuselage? Imagine a F5 ish body with dual engines on the place of intakes. That would not have a very big inertia compared to engines inside the body. Or putting an engine on top of the body like heinkel he162. That wouldn't have that much of a bigger moment of inertia?
Because aircraft have to have enough yaw authority to overcome the torque of a single engine going out. Further spaced engines means a larger rudder is necessary and bulkier reinforcing structure, which means more weight and lower performance.
Only thanks to modern advances in engines. Go back to the 1960s and (most) everything was twin engine because engine reliability was (comparatively) shit. They not only planned for engine-out scenarios, they *expected* them. These days, the engines are *much* more reliable and single engine designs are increasingly favored for reasons of logistics.
Dual engines are apparently still preferred for air superiority ( f15, F22), whereas the lightweight (budget) fighters were single engine. The navy also preferred dual engines for redundancy since losing an only engine at sea caused water retention issues. My understanding is they were very reluctant to accept the JSF program as a single engine, but that’s what it needed for cost.
Goose’s death faithfully reflected how the F14 often behaved when losing an engine in a dynamic flight regime. They’d enter an unrecoverable flat spin, immediate ejection was mandatory. If you were very unlucky and didn’t jettison the canopy before ejecting the auto-jettison in the ejection sequence might not allow enough time for the canopy to separate far enough.
My Dad was an F14 pilot when we first saw _Top Gun_. He wasn’t a big fan because he thought the depictions of fighter pilots were exaggerated and cartoonish (but not, mind you, completely inaccurate lol). He thought the ejection sequence was the most accurate and best researched sequence in the film.
The F14 was a fantastic airplane beloved by its crews. But the A models were cursed by their TF30 engines, which themselves were a holdover from McNamara’s ill considered economization measures and the F-111 program. It had some very very nasty traits that would kill you in an heartbeat if you strayed into certain areas of the flight envelope and didn’t immediately do all the right things in the right order and none of the wrong things. [Kara Hultgren’s accident](https://en.m.wikipedia.org/wiki/Kara_Hultgreen) is another example of this.
Sure, and there were single engine planes back then too (see: F-86 and contemporaries). Still, by the 1960s everybody wanted two engines. While the A-7 bucked the trend, I'm not aware of any other F/A planes to enter service in that decade that didn't have two engines. A quick check on Wiki indicates that every other F/A aircraft first flight from 1958 until 1974 (F-16) had two engines. And there were more than a few planes introduced in that era.
As pointed out, maneuverability/handling is probably the biggest one. A few other considerations: less drag with engines built into fuselage (higher speed and better fuel efficiency) and more room for weapons (wing pylons) with engines built into fuselage.
I liked your engineering physics explanation!
For those of you who don't know, this is taught in cal based physics 1: First semester college physics for engineers
Others have mentioned physical considerations, but I'll throw in the radar one:
4th gen fighters still have concerns about radar cross section - they just don't commit as fully to it as truly stealth aircraft do. For example, a modern F-16 (meaning the model currently in use by the USAF today) has roughly the same radar cross section as a "5th gen" Su-57 "stealth" fighter. Earlier Block F-16s (meaning earlier models) had larger RCS, but were adjusted to minimize it as technology advanced. Block 60 (modern) F-16s were given things like S-ducts (engine intakes) and sloped radar arrays for that reason.
The reason that's important is that stealth isn't a flat 'yes/no' - the smaller your RCS, the closer you have to be before a given radar can see you, and the easier it is to get lost in clutter
Stealth is not a y/n is correct, if you detect your opponent before your opponent detects you, that'll allow you to attack, and force your opponent to defend.
They are probably more stealthy than the ME 262.
I suspect they might not be "stealth" aircraft but they still have a smaller signature. This could be helpful in avoiding AA missiles.
The Me262 was surprisly more stealth then you would think thanks to the triangular fuselage. ( It reflected the radar waves away from the source).
The engines ofcourse ruined it, but it gave radar engineers some insight into Building stealth aircraft. ( The yb-49 shortly afterwards gave them a whole new perspective, so the Me262 was quickly forgotten.)
This is just silly. The Me-262 was hardly a point of insight towards the design of stealth aircraft and would stand out on radar. Stealth design wasn’t something that would begin in earnest until the 1970s in the US (later elsewhere) when DARPA tasked Lockheed and Northrop with developing LO aircraft. at which point there were far more advanced designs than a shitty ww2 fighter to draw inspiration from.
Baby steps ... In WW2 both sides were very interested in trying to avoid getting detected by radar... The Germans had RAM materials applied to submarine snorkels to avoid being blown out of the water by Allied patrol planes... The material was heavy and primitive, but it did a decent job. They also had no idea why some planes were more visible on radar then others. The wooden Mosquito was a plane that hard to follow-at certain angles- on its course towards the mainland.
The early days of radar research are clouded in mystery because of the cold war and national security.
DARPA didn't invent stealth either, they suspected that it would be possible to reduce radar returns. So they started a study and contacted some firms. They didn't just task Lockheed and Northrop out of the blue to develop a stealth airplane, the companies already had done some research in that field ( the yb-49 I mentioned) and other research aircraft developed for other programs, but that never made it to production.
Lockheed was actually too late when they heard about the study/project , but they made the A-12 for the CIA and had to get clearance from the CIA to tell DARPA that they could do this.
It’s a Nazi wunderwaffe so it must be powered by space magic right? Just ignore the fact that it was not stealthy and was designed by people who had zero knowledge of radar stealth characteristics, all in an era before airborne radar existed in any air force. But sure the fuselage is vaguely triangle shaped and the F-117 was vaguely triangle shaped so therefore it must have been a stealth fighter.
Lol. I think the Allies discovered it after the war. The Germans didn't design it with intent to be more stealthy, it was just a by-product of the shape of the fuselage.
You are very informed about flying radars I can tell. You might find A.I. mk IV or the H2X or the FuG202 an interesting read....
Everyone knows that all German planes were made with Unobtianium that they found in a secret Alien spaceship that crashed inside the hollow Earth.....
Me262 was actually originally designed with jet engines inside the roots of the wings, and straight wings just like British Meteor was.
However 262 was designed while engine was still being developed. So designers decided to move engines to underwing pods... so if engines ended up being significantly different, they didn't had to change the whole plane.
Engines did turn out to be both bigger and more massive. This is why 262 got swept wings, to move heavier engines back and keep it's center of mass. Turns out swept wings increased critical Mach number, which was good.
But as another redditor already said, having mass far away from the center of the mass increases inertia... reduces agility. It takes longer to start rolling, and longer to stop rolling... sluggish commands.
Engines of this era failed somewhat regularly. If the engines are off the aircraft centreline then a failure of one results in considerable yaw (or pitch) moment; this could result in unrecoverable spin. Placing the engines as close together as possible mitigates this issue.
Pros Radar cross section; agility; reduced drag
Cons Harder to change engines and other kit. , High performance in the hanger is not an asset, it is just a target.
Another reason is that if one engine goes out, the remaining engine gives a very large thrust imbalance because of its large moment arm from your center of mass, so you'd have to do a hard rudder to counter it (which adds drag and likely limits your thrust even further in order not to lose control). You may even lose control of the aircraft altogether if the failure happens before you can react to it.
So like Convair-58 hustler or Rockwell B-1 or Concorde or SR-71 .
How many fighters have more than 1 engine? F-4 phantom. I kinda sits on its engines.
Sukhoi and Mig have external engine nacelles.
English Electric lighting was all about area rule. So in line: RADAR cockpit engine
Actually the Lightning was pre-area rule - it was just designed to mjnimise frontal area, which is very different. When they build the trainer with side by side seats, it was something of a surprise that the performance was similar to that of the single-seater. That happened because the cross-sectional area was closer to constant along the length of the plane, ie it conformed more closely to the area rule.
To me it looks like they design it like a modern jetliner: keep the area of the fuselage constant next to the wings. Hard to believe for me that the trainer would have similar top speed ( important for an interceptor) . I could understand that it goes supersonic as easily.
The area rule needs the cross-section constant along the length, not just where the wings are. Have a look at a Blackburn Buccaneer for an example. This is why having a wider front fuselage in front of the wings did not have a penalty. Current airliners are not great examples for the area rule, probably because they are designed to stop the air flow going supersonic, and they want to avoid the complications of a non-cylindrical fuselage. Something like the Boeing 2707 shows area ruling of the fuselage.
Look at the Lockheed constellation! Jetliner designers once thought that the fuselage should look like a football ( not soccer ). The 707 had its nacelles under the wing! Area rule puts the engines in front of the wing where they belong.
Fighters have cylindrical engines and engine bays, to be able to pull them out of the back. Only area rule is cockpit, wing, vertical, horizontal.
Because that’s more mass out board of the wings which means it has a bigger moment of inertia. Moment of inertia is the resistance to something rotating or spinning. By moving the mass towards the center, you reduce the moment of inertia and for the same amount of angular momentum you would spin faster. This is the equivalent to a figure skater pulling their arms in to make them spin faster. For a fighter yet you want high angular rates so you want to minimize your moment of inertia wherever possible.
It also means more drag. Outboard have significantly more surface area
Makes sense. What about putting 2 engines on the wings but also near the main body fuselage? Imagine a F5 ish body with dual engines on the place of intakes. That would not have a very big inertia compared to engines inside the body. Or putting an engine on top of the body like heinkel he162. That wouldn't have that much of a bigger moment of inertia?
Because aircraft have to have enough yaw authority to overcome the torque of a single engine going out. Further spaced engines means a larger rudder is necessary and bulkier reinforcing structure, which means more weight and lower performance.
So f16 f35 truly are superior designs :sob:
Only thanks to modern advances in engines. Go back to the 1960s and (most) everything was twin engine because engine reliability was (comparatively) shit. They not only planned for engine-out scenarios, they *expected* them. These days, the engines are *much* more reliable and single engine designs are increasingly favored for reasons of logistics.
Dual engines are apparently still preferred for air superiority ( f15, F22), whereas the lightweight (budget) fighters were single engine. The navy also preferred dual engines for redundancy since losing an only engine at sea caused water retention issues. My understanding is they were very reluctant to accept the JSF program as a single engine, but that’s what it needed for cost.
Water retention issues 🤣
The ending of Top Gun Maverick when one engine flames out is hilarious, when you know the history of that F14 jet
Goose’s death faithfully reflected how the F14 often behaved when losing an engine in a dynamic flight regime. They’d enter an unrecoverable flat spin, immediate ejection was mandatory. If you were very unlucky and didn’t jettison the canopy before ejecting the auto-jettison in the ejection sequence might not allow enough time for the canopy to separate far enough. My Dad was an F14 pilot when we first saw _Top Gun_. He wasn’t a big fan because he thought the depictions of fighter pilots were exaggerated and cartoonish (but not, mind you, completely inaccurate lol). He thought the ejection sequence was the most accurate and best researched sequence in the film. The F14 was a fantastic airplane beloved by its crews. But the A models were cursed by their TF30 engines, which themselves were a holdover from McNamara’s ill considered economization measures and the F-111 program. It had some very very nasty traits that would kill you in an heartbeat if you strayed into certain areas of the flight envelope and didn’t immediately do all the right things in the right order and none of the wrong things. [Kara Hultgren’s accident](https://en.m.wikipedia.org/wiki/Kara_Hultgreen) is another example of this.
Was the F14 a problem with only one engine?
The gag is that one of the engines would flame out, from reading the Wikipedia on F14 and the references.
F16 design started in the late 50s.
Sure, and there were single engine planes back then too (see: F-86 and contemporaries). Still, by the 1960s everybody wanted two engines. While the A-7 bucked the trend, I'm not aware of any other F/A planes to enter service in that decade that didn't have two engines. A quick check on Wiki indicates that every other F/A aircraft first flight from 1958 until 1974 (F-16) had two engines. And there were more than a few planes introduced in that era.
Why SOB? Physics, baby. Pin that maneuverability around a single axis of thrust. There's a reason they are still relevant.
Thank you
Source: Top Gun (1984)
As pointed out, maneuverability/handling is probably the biggest one. A few other considerations: less drag with engines built into fuselage (higher speed and better fuel efficiency) and more room for weapons (wing pylons) with engines built into fuselage.
Some had engines in the wing root (and look fucking sexy) but the wing really needs this space more.
I liked your engineering physics explanation! For those of you who don't know, this is taught in cal based physics 1: First semester college physics for engineers
Others have mentioned physical considerations, but I'll throw in the radar one: 4th gen fighters still have concerns about radar cross section - they just don't commit as fully to it as truly stealth aircraft do. For example, a modern F-16 (meaning the model currently in use by the USAF today) has roughly the same radar cross section as a "5th gen" Su-57 "stealth" fighter. Earlier Block F-16s (meaning earlier models) had larger RCS, but were adjusted to minimize it as technology advanced. Block 60 (modern) F-16s were given things like S-ducts (engine intakes) and sloped radar arrays for that reason. The reason that's important is that stealth isn't a flat 'yes/no' - the smaller your RCS, the closer you have to be before a given radar can see you, and the easier it is to get lost in clutter
Stealth is not a y/n is correct, if you detect your opponent before your opponent detects you, that'll allow you to attack, and force your opponent to defend.
They are probably more stealthy than the ME 262. I suspect they might not be "stealth" aircraft but they still have a smaller signature. This could be helpful in avoiding AA missiles.
The Me262 was surprisly more stealth then you would think thanks to the triangular fuselage. ( It reflected the radar waves away from the source). The engines ofcourse ruined it, but it gave radar engineers some insight into Building stealth aircraft. ( The yb-49 shortly afterwards gave them a whole new perspective, so the Me262 was quickly forgotten.)
This is just silly. The Me-262 was hardly a point of insight towards the design of stealth aircraft and would stand out on radar. Stealth design wasn’t something that would begin in earnest until the 1970s in the US (later elsewhere) when DARPA tasked Lockheed and Northrop with developing LO aircraft. at which point there were far more advanced designs than a shitty ww2 fighter to draw inspiration from.
Baby steps ... In WW2 both sides were very interested in trying to avoid getting detected by radar... The Germans had RAM materials applied to submarine snorkels to avoid being blown out of the water by Allied patrol planes... The material was heavy and primitive, but it did a decent job. They also had no idea why some planes were more visible on radar then others. The wooden Mosquito was a plane that hard to follow-at certain angles- on its course towards the mainland. The early days of radar research are clouded in mystery because of the cold war and national security. DARPA didn't invent stealth either, they suspected that it would be possible to reduce radar returns. So they started a study and contacted some firms. They didn't just task Lockheed and Northrop out of the blue to develop a stealth airplane, the companies already had done some research in that field ( the yb-49 I mentioned) and other research aircraft developed for other programs, but that never made it to production. Lockheed was actually too late when they heard about the study/project , but they made the A-12 for the CIA and had to get clearance from the CIA to tell DARPA that they could do this.
It’s a Nazi wunderwaffe so it must be powered by space magic right? Just ignore the fact that it was not stealthy and was designed by people who had zero knowledge of radar stealth characteristics, all in an era before airborne radar existed in any air force. But sure the fuselage is vaguely triangle shaped and the F-117 was vaguely triangle shaped so therefore it must have been a stealth fighter.
Lol. I think the Allies discovered it after the war. The Germans didn't design it with intent to be more stealthy, it was just a by-product of the shape of the fuselage. You are very informed about flying radars I can tell. You might find A.I. mk IV or the H2X or the FuG202 an interesting read.... Everyone knows that all German planes were made with Unobtianium that they found in a secret Alien spaceship that crashed inside the hollow Earth.....
Me262 was actually originally designed with jet engines inside the roots of the wings, and straight wings just like British Meteor was. However 262 was designed while engine was still being developed. So designers decided to move engines to underwing pods... so if engines ended up being significantly different, they didn't had to change the whole plane. Engines did turn out to be both bigger and more massive. This is why 262 got swept wings, to move heavier engines back and keep it's center of mass. Turns out swept wings increased critical Mach number, which was good. But as another redditor already said, having mass far away from the center of the mass increases inertia... reduces agility. It takes longer to start rolling, and longer to stop rolling... sluggish commands.
Engines of this era failed somewhat regularly. If the engines are off the aircraft centreline then a failure of one results in considerable yaw (or pitch) moment; this could result in unrecoverable spin. Placing the engines as close together as possible mitigates this issue.
Pros Radar cross section; agility; reduced drag Cons Harder to change engines and other kit. , High performance in the hanger is not an asset, it is just a target.
Another reason is that if one engine goes out, the remaining engine gives a very large thrust imbalance because of its large moment arm from your center of mass, so you'd have to do a hard rudder to counter it (which adds drag and likely limits your thrust even further in order not to lose control). You may even lose control of the aircraft altogether if the failure happens before you can react to it.
So like Convair-58 hustler or Rockwell B-1 or Concorde or SR-71 . How many fighters have more than 1 engine? F-4 phantom. I kinda sits on its engines. Sukhoi and Mig have external engine nacelles. English Electric lighting was all about area rule. So in line: RADAR cockpit engine
Actually the Lightning was pre-area rule - it was just designed to mjnimise frontal area, which is very different. When they build the trainer with side by side seats, it was something of a surprise that the performance was similar to that of the single-seater. That happened because the cross-sectional area was closer to constant along the length of the plane, ie it conformed more closely to the area rule.
To me it looks like they design it like a modern jetliner: keep the area of the fuselage constant next to the wings. Hard to believe for me that the trainer would have similar top speed ( important for an interceptor) . I could understand that it goes supersonic as easily.
The area rule needs the cross-section constant along the length, not just where the wings are. Have a look at a Blackburn Buccaneer for an example. This is why having a wider front fuselage in front of the wings did not have a penalty. Current airliners are not great examples for the area rule, probably because they are designed to stop the air flow going supersonic, and they want to avoid the complications of a non-cylindrical fuselage. Something like the Boeing 2707 shows area ruling of the fuselage.
Look at the Lockheed constellation! Jetliner designers once thought that the fuselage should look like a football ( not soccer ). The 707 had its nacelles under the wing! Area rule puts the engines in front of the wing where they belong. Fighters have cylindrical engines and engine bays, to be able to pull them out of the back. Only area rule is cockpit, wing, vertical, horizontal.
Yeah thats what I meant.