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> The B-52 of today was iteratively designed over decades and the current H models are entirely different planes than earlier models (although structurally very

> The B-52 of today was iteratively designed over decades and the current H models are entirely different planes than earlier models (although structurally very close to the G model). The plane was only ever produced for a decade and the H model was last produced in 1963. Obviously it has been retrofitted with new engines, avionics, armaments, etc, but it's not a fundamentally different plane.

hef19898 4y ago
If every thing except the overall form of the fuselage is changed it is a new plane.
- justsomehnguy 4y ago
  Only if the new plane is not Tu-144 or Buran. Then it's not a new plane, but a stolen one. /s
  - p_l 4y ago
    Buran was made to look like Shuttle (despite opposition of engineers on the project), but was completely local design.
    - aerostable_slug 4y ago
      How does one separate the outer mold line of the spacecraft from its performance? Isn't Buran's appearance driven by similar requirements vs. aesthetics? What else would it have looked like — if you want lots of crossrange capability, you're not going to get something that looked like Faget's designs, would you?
      - p_l 4y ago
        Buran had different design requirements (once you discard the political), because unlike STS the orbiter wasn't sole launcher of the system - Energia took care of shipping heavy cargo to whatever orbit you wanted. So they had different set of constraints including size & prospective contents of the cargo bay. They have also flirted with the idea of just putting two jet engines into orbiter for extra cross range, which was probably not an option on STS given the huge dead weight of engines
        aerostable_slug 4y ago
        It wasn't needed because the STS wing area achieved the goal of not overflying the Soviets after dropping off a military satellite (once-around mission out of Vandenberg SLC-6), and the US had many politically friendly potential landing areas, while USSR did not. Catering to NRO and USAF wartime requirements doomed the STS to cost overruns. Sticking with Faget's designs and the NASA requirements may have salvaged the program's cost goals, but I'm no expert.
        p_l 4y ago
        The two stage design from IIRC phase II of Shuttle project was a marvel
    - justsomehnguy 4y ago
      > despite opposition of engineers on the project Huh? Despite 'opposition'? Can you elaborate? (also make sure not to miss /s in my previous comment)
      - p_l 4y ago
        I didn't miss the /s, but I feared others might think different ;) From what I've read, the decisions to make Buran look externally like STS orbiter was a political one, and the engineers at MiG OKB weren't happy about it - they have been working on a bunch of space planes for some time, including the infamous suborbital fighter. However the similarity was found to have political benefits in the weird opposite of kremlinology and the decision stood. Not having USAF's annoying requirements though, they were able to design a better system anyway. (Pre-USAF involvement STS was also better, but congress cost cutting made a necessity of begging DoD for funds)
        justsomehnguy 4y ago
        I checked the Wiki article on it, just to be sure. I just don't understand how it could look any way different (at least significantly), this is a classical case of the function dictating the form.
        p_l 4y ago
        Essentially, the Buran orbiter had different function, and thus different forces on its form. US' STS shape was ultimately dictated by its cross range requirements combined with cargo capacity. Explicit case of function leading to specific form. Buran didn't require the same huge cargo capacity in the orbiter, because Soviets had already tested and verified self-assembly of space station in orbit from multiple launched modules (technology that they would later employ in ISS). For huge capacity it had Energia, which once proven could be also launched on Polar orbits (the specific requirements from USAF for STS involved heavy cargo on polar orbits from Vandenberg). This meant that Buran orbiter had wider design space to explore, and previous experiments in crewed reusable spacecraft were centered around lifting body shape, to extent much higher than STS was. However, the command to make it look like US STS came pretty early in the project, in addition to general lack of documents, so we don't really know how they would go.
    - paganel 4y ago
      I’ve not read too much on the Soviet space program, but whenever I read about Buran (a wonderful accomplishment per se) my thought process goes something like this: “The Soviets must have seen the Americans working on the shuttle thing -> the Soviets must have thought that that shuttle thing was great mostly on account of the Americans working on it -> the Soviets built a shuttle system for themselves -> the Soviets threw away lots of resources for almost nothing”. Also, as it became apparent in the meantime, even the Americans didn’t get it right when it came to the reasons behind building the shuttle system. As far as I understood there were other, less expensive ways, that they could have taken in order to “improve” their space program.
      - p_l 4y ago
        Buran system was very, very different from US' STS, and honestly multiple groups combined under one umbrella to get what they wanted in Buran project. Some bits of Buran were a "me too" (the visual look of the orbiter, for political reasons), but Soviet space program has combined multiple previous tracks that existed independent of what Americans were doing. Among various tracks that combined together, there was 1. Super Heavy Launcher - a long term dream since the failure of N1, realised in Energia 2. Reusable crewed orbiter - Buran orbiter 3. Mir-2, the successor to Mir space station - was supposed to use (1) for construction and (2) for crew 4. Fully reusable launch vehicle - was proposed continuation of Energia project 5. various missions requiring super heavy launchers (either Energia, or prospective Vulkan which added extra energia core stage on top) - including mars missions that were on slow boil since end of moon program 6. Soviet Space Forces - anti-SDI systems, orbital warfare unmanned cruisers (Polyot) etc. - dependant on (1). 7. Reduction of space construction and launch costs - nuclear-powered orbital tug launched by Energia which would be responsible for moving objects from low LEO to target orbit, including GEO 1,2,4, and 7 were all included directly in the scope of Buran, with Polyot (6) being in progress as well (the other Energia launch was launch of Polyot test unit). Note that Buran orbiter, the one part that resembled Shuttle, is independent of other tasks though considered beneficial for the space station goals - if the orbiter project failed, it would still provide data for Reusable Energia variant, and Energia would still mean a working 100t-to-LEO system they could use for whatever - unlike Shuttle which was one specific vehicle. This also meant that Buran's orbiter had much lower cargo capacity - because it didn't need to have higher one as space station modules and the like could just use Energia.
- rgoulter 4y ago
  https://en.wikipedia.org/wiki/Ship_of_Theseus https://en.wikipedia.org/wiki/Ship_of_Theseus
- tyingq 4y ago
  I don't think that's unusual at all for any jet aircraft that's around for decades. They almost all get new engines, avionics, etc. That the B-52 still has 8 engines is somewhat surprising...that's not terribly desirable.
  - nradov 4y ago
    The Air Force considered replacing the 8 engines with 4 more powerful ones. However, they determined that the loss of one of those engines on take-off would cause a dangerous thrust asymmetry. Dealing with that would have required more extensive changes like moving the engine mounts, so they dropped the idea. But they are going to replace the engines with newer models. https://www.thedrive.com/the-war-zone/42517/rolls-royce-will-provide-long-awaited-new-jet-engines-for-the-b-52-bomber-fleet https://www.thedrive.com/the-war-zone/42517/rolls-royce-will...
    - LgWoodenBadger 4y ago
      I had seen/heard/read that the thrust asymmetry was a design feature to help with yaw, and that fewer engines would overpower the design limits of other parts of the airplane, to the extent that everything else would need to be redesigned to handle them (mounts, tail, rudder, etc.) edit: I believe this is the original video where I saw the above https://www.youtube.com/watch?v=02_geGISTLg https://www.youtube.com/watch?v=02_geGISTLg
      - palunon 4y ago
        You can use thrust asymmetry to help with yaw, yes. But here we're talking about unplanned sudden thrust asymmetry, causing a massive yaw force at a critical phase of flight, takeoff, where you're engines are likely to be near their full power and you're close to/on the ground. If you go from 8 engines to 4, loosing one engine goes from causing 25% thrust loss on the wing to 50%.
        tyingq 4y ago
        Makes sense, but must be also tied to something else unique about the B-52. There are certainly much larger aircraft with 4 engines.
- usrusr 4y ago
  ..for certain definitions of "new" (last built 60 years ago)
- bell-cot 4y ago
  What if most major structural elements of the plane, the skin, the control surfaces, etc. are ~1960 original? Multiple rounds of upgrading avionics, weapons, engines, etc. are extremely common in military planes.
themadturk 4y ago
It's worth noting that the C-130 Hercules has been in continuous service since 1956, and new aircraft were still being produced at least as recently as 2015 (and perhaps longer). That aircraft really is a flying truck!

hef19898 4y ago

If every thing except the overall form of the fuselage is changed it is a new plane.

justsomehnguy 4y ago
Only if the new plane is not Tu-144 or Buran. Then it's not a new plane, but a stolen one. /s
- p_l 4y ago
  Buran was made to look like Shuttle (despite opposition of engineers on the project), but was completely local design.
  - aerostable_slug 4y ago
    How does one separate the outer mold line of the spacecraft from its performance? Isn't Buran's appearance driven by similar requirements vs. aesthetics? What else would it have looked like — if you want lots of crossrange capability, you're not going to get something that looked like Faget's designs, would you?
    - p_l 4y ago
      Buran had different design requirements (once you discard the political), because unlike STS the orbiter wasn't sole launcher of the system - Energia took care of shipping heavy cargo to whatever orbit you wanted. So they had different set of constraints including size & prospective contents of the cargo bay. They have also flirted with the idea of just putting two jet engines into orbiter for extra cross range, which was probably not an option on STS given the huge dead weight of engines
      - aerostable_slug 4y ago
        It wasn't needed because the STS wing area achieved the goal of not overflying the Soviets after dropping off a military satellite (once-around mission out of Vandenberg SLC-6), and the US had many politically friendly potential landing areas, while USSR did not. Catering to NRO and USAF wartime requirements doomed the STS to cost overruns. Sticking with Faget's designs and the NASA requirements may have salvaged the program's cost goals, but I'm no expert.
        p_l 4y ago
        The two stage design from IIRC phase II of Shuttle project was a marvel
  - justsomehnguy 4y ago
    > despite opposition of engineers on the project Huh? Despite 'opposition'? Can you elaborate? (also make sure not to miss /s in my previous comment)
    - p_l 4y ago
      I didn't miss the /s, but I feared others might think different ;) From what I've read, the decisions to make Buran look externally like STS orbiter was a political one, and the engineers at MiG OKB weren't happy about it - they have been working on a bunch of space planes for some time, including the infamous suborbital fighter. However the similarity was found to have political benefits in the weird opposite of kremlinology and the decision stood. Not having USAF's annoying requirements though, they were able to design a better system anyway. (Pre-USAF involvement STS was also better, but congress cost cutting made a necessity of begging DoD for funds)
      - justsomehnguy 4y ago
        I checked the Wiki article on it, just to be sure. I just don't understand how it could look any way different (at least significantly), this is a classical case of the function dictating the form.
        p_l 4y ago
        Essentially, the Buran orbiter had different function, and thus different forces on its form. US' STS shape was ultimately dictated by its cross range requirements combined with cargo capacity. Explicit case of function leading to specific form. Buran didn't require the same huge cargo capacity in the orbiter, because Soviets had already tested and verified self-assembly of space station in orbit from multiple launched modules (technology that they would later employ in ISS). For huge capacity it had Energia, which once proven could be also launched on Polar orbits (the specific requirements from USAF for STS involved heavy cargo on polar orbits from Vandenberg). This meant that Buran orbiter had wider design space to explore, and previous experiments in crewed reusable spacecraft were centered around lifting body shape, to extent much higher than STS was. However, the command to make it look like US STS came pretty early in the project, in addition to general lack of documents, so we don't really know how they would go.
  - paganel 4y ago
    I’ve not read too much on the Soviet space program, but whenever I read about Buran (a wonderful accomplishment per se) my thought process goes something like this: “The Soviets must have seen the Americans working on the shuttle thing -> the Soviets must have thought that that shuttle thing was great mostly on account of the Americans working on it -> the Soviets built a shuttle system for themselves -> the Soviets threw away lots of resources for almost nothing”. Also, as it became apparent in the meantime, even the Americans didn’t get it right when it came to the reasons behind building the shuttle system. As far as I understood there were other, less expensive ways, that they could have taken in order to “improve” their space program.
    - p_l 4y ago
      Buran system was very, very different from US' STS, and honestly multiple groups combined under one umbrella to get what they wanted in Buran project. Some bits of Buran were a "me too" (the visual look of the orbiter, for political reasons), but Soviet space program has combined multiple previous tracks that existed independent of what Americans were doing. Among various tracks that combined together, there was 1. Super Heavy Launcher - a long term dream since the failure of N1, realised in Energia 2. Reusable crewed orbiter - Buran orbiter 3. Mir-2, the successor to Mir space station - was supposed to use (1) for construction and (2) for crew 4. Fully reusable launch vehicle - was proposed continuation of Energia project 5. various missions requiring super heavy launchers (either Energia, or prospective Vulkan which added extra energia core stage on top) - including mars missions that were on slow boil since end of moon program 6. Soviet Space Forces - anti-SDI systems, orbital warfare unmanned cruisers (Polyot) etc. - dependant on (1). 7. Reduction of space construction and launch costs - nuclear-powered orbital tug launched by Energia which would be responsible for moving objects from low LEO to target orbit, including GEO 1,2,4, and 7 were all included directly in the scope of Buran, with Polyot (6) being in progress as well (the other Energia launch was launch of Polyot test unit). Note that Buran orbiter, the one part that resembled Shuttle, is independent of other tasks though considered beneficial for the space station goals - if the orbiter project failed, it would still provide data for Reusable Energia variant, and Energia would still mean a working 100t-to-LEO system they could use for whatever - unlike Shuttle which was one specific vehicle. This also meant that Buran's orbiter had much lower cargo capacity - because it didn't need to have higher one as space station modules and the like could just use Energia.
rgoulter 4y ago
https://en.wikipedia.org/wiki/Ship_of_Theseus https://en.wikipedia.org/wiki/Ship_of_Theseus
tyingq 4y ago
I don't think that's unusual at all for any jet aircraft that's around for decades. They almost all get new engines, avionics, etc. That the B-52 still has 8 engines is somewhat surprising...that's not terribly desirable.
- nradov 4y ago
  The Air Force considered replacing the 8 engines with 4 more powerful ones. However, they determined that the loss of one of those engines on take-off would cause a dangerous thrust asymmetry. Dealing with that would have required more extensive changes like moving the engine mounts, so they dropped the idea. But they are going to replace the engines with newer models. https://www.thedrive.com/the-war-zone/42517/rolls-royce-will-provide-long-awaited-new-jet-engines-for-the-b-52-bomber-fleet https://www.thedrive.com/the-war-zone/42517/rolls-royce-will...
  - LgWoodenBadger 4y ago
    I had seen/heard/read that the thrust asymmetry was a design feature to help with yaw, and that fewer engines would overpower the design limits of other parts of the airplane, to the extent that everything else would need to be redesigned to handle them (mounts, tail, rudder, etc.) edit: I believe this is the original video where I saw the above https://www.youtube.com/watch?v=02_geGISTLg https://www.youtube.com/watch?v=02_geGISTLg
    - palunon 4y ago
      You can use thrust asymmetry to help with yaw, yes. But here we're talking about unplanned sudden thrust asymmetry, causing a massive yaw force at a critical phase of flight, takeoff, where you're engines are likely to be near their full power and you're close to/on the ground. If you go from 8 engines to 4, loosing one engine goes from causing 25% thrust loss on the wing to 50%.
      - tyingq 4y ago
        Makes sense, but must be also tied to something else unique about the B-52. There are certainly much larger aircraft with 4 engines.
usrusr 4y ago
..for certain definitions of "new" (last built 60 years ago)
bell-cot 4y ago
What if most major structural elements of the plane, the skin, the control surfaces, etc. are ~1960 original? Multiple rounds of upgrading avionics, weapons, engines, etc. are extremely common in military planes.

themadturk 4y ago

It's worth noting that the C-130 Hercules has been in continuous service since 1956, and new aircraft were still being produced at least as recently as 2015 (and perhaps longer). That aircraft really is a flying truck!