4 ms·

It’s easy to build an airplane. It’s hard to build one that lasts 30-50 years and to prove that it has an acceptably low failure rate.

fargle 3y ago
It's absolutely not easy to build an airplane. It's incredibly difficult to build an airplane, especially a completely new design. It's absolutely impossible to do that at the same time as making one that will last 30-50 years and have a low failure rate. What is difficult, incredibly expensive, and very time-consuming, but possible - barely - is starting with the first airplane and eventually getting to the second. The first is the job of a Skunk Works. The second is the job of more traditional aerospace organizations.
- wiz21c 3y ago
  I'm not in airplane engineering, so: > It's incredibly difficult to build an airplane, especially a completely new design. why ?
  - snovv_crash 3y ago
    Aerodynamics. Structural design. Design for manufacturing and assembly. Power and drivetrain. Control systems and actuators. Avionics. And then get all of these to a reliability level where you feel comfortable with a single failure causing high likelihood of multiple human deaths.
  - intotheabyss 3y ago
    As someone who is in airplane engineering, the biggest barrier today to building a new aircraft is regulations. But if we completely ignored regulations, and you were building a mostly aluminum aircraft with analog avionics and the goal was just to get it to fly (nevermind things like designing for fatigue), then no it wouldn't be that difficult conceptually on paper. However, manufacturing would still be the bottleneck, and that is still challenging today (tolerances, QA, technical expertise). However, if you were designing and building a new aircraft to meet the latest Part 25 regulations for passenger transport, it's almost insurmountable. There's a reason why there are so few aircraft OEMs.
    - tonyarkles 3y ago
      And to go along with it for Part 25, you're pretty much guaranteed to be doing something "thinking outside the box" if you're doing a clean-sheet design, because the current models (737 Max8, A320, etc) are all pretty darned close to their local optima. No one's going to do a clean-sheet design for 5% more pax and 5% less fuel burn, they're just going to riff on something that already has type approval so that a good chunk of the regulatory burden is already mostly taken care of.
  - fargle 3y ago
    I agree with the sibling comments, but let me add a few ideas. Let's not even worry about the bureaucracy, safety regulations, etc. for a "Skunk Works" phase. The safety and reliability stuff is even harder, but just the first phase of building anything that flies is really hard. Aircraft design requires truly careful engineering. There is very little leeway. EVERYTHING is a trade-off. You have huge forces and need very light weight. You add a pound of structure to tolerate the loads, now you have more loads and need more power all of which adds weight, requiring more fuel to make range. All of that requires more structure, which adds weight. To find a workable design that "closes" is hard because there is a very small corner of the design envelope that will even work. It's also hard because when working at these extremes of what is even possible, there is no room for failure and you can't just add reliability by brute force (adding more power, more metal, etc.). There are fine margins because you can't afford thick ones. And to live with these fine margins, you must have extremely tight manufacturing tolerances and predictable performance. Aircraft are also a very complicated system. The physics are complicated, the behavior of all the required subsystems is complicated. So now, you have to do the most precise careful engineering you can think of, across a set of super complicated interdependent systems. So all of this costs a lot of money, and at some point - for a new design - it has to take off for the first time. At that point, basically nothing can go wrong. You can't exactly fire up gdb, find the bug and recompile. There is no edit-compile-test cycle (well, or it's a very short cycle). The only thing that seems harder is rocket design. Actually turbo-pump design for the engines for the rockets.
    - wiz21c 3y ago
      ok I see but at the same time, I guess there is a ton of knowledge about previous planes floating around. You don't do it from scratch, do you ? Processor are really hard to do, as well as software for physics simulation, as well as a ton of other things. But for both of them, I can confidently say that nobody starts from scratch: it's improvements upon improvements and from time to time, a bit of breakthrough... I do understand that the safety aspect is pretty specific and really tough to get right.
      - fargle 3y ago
- KeplerBoy 3y ago
  It's not that hard. Slap a motor and a few servos on a piece of cardboard and you've got yourself a model airplane. Sometimes I'm surprised how easy it is to get something flying.
  - SketchySeaBeast 3y ago
    print('Hello world!') Man, I don't know why anyone says that software development is hard.
    - intelVISA 3y ago
      excuse me where's the semi-colon? Unshippable!!
      - opan 3y ago
        It's valid python3.
  - tonyarkles 3y ago
    You're unfortunately getting downvoted but you're totally right. https://store.flitetest.com/park-flyers-swappables/ https://store.flitetest.com/park-flyers-swappables/ I work in the UAS industry and we absolutely do use things like these cardboard airframes for prototyping. They're awesome out of the box and really easy to repair with some tape and hot-melt glue if necessary.
vikramkr 3y ago
I have no idea what point you're trying to make - and also it definitely isn't easy to build an airplane. R&D, prototyping, and manufacturing are all hard
- whalesalad 3y ago
  When you look at what the skunk works were doing back in the day with drafting tables and plywood you would also think it’s easy. These days less so due to electronic/computer driven flight surfaces and all the crazy sensing
shakow 3y ago
> It’s hard to build one that lasts 30-50 years Like the U-2, the SR-71, or the F-117?
- dotancohen 3y ago
  The U-2 is still flying, even though it was expected to be obsolete quickly. The SR-71 and F-117 are no longer operational, I think they both were retired before 30 years of service. Military aircraft lifespans rarely fit their projected timeframes.
  - _djo_ 3y ago
    The F-117s are technically still operational, even after their official retirement. https://www.thedrive.com/the-war-zone/retired-f-117-nighthawks-may-fly-for-another-decade https://www.thedrive.com/the-war-zone/retired-f-117-nighthaw...
    - hef19898 3y ago
      Flying is dofferent from being operational in the military sense. Still impressive that those bird are still airworzhy so.
      - _djo_ 3y ago
        They're still operational systems in the military sense, just no longer front line combat assets. They've been relegated to R&D & training.
        hef19898 3y ago
        So they no longer have operational capabilitied for their initially intended role.
        _djo_ 3y ago
        Yes, but this is splitting hairs a bit. Are training systems considered operational? It depends. In a systems readiness point of view, yes, they're operational even if they've been re-roled, as opposed to being withdrawn-from-use or having another status. But if you consider only front-line combat systems operational and exclude all other aircraft including training aircraft like the USAF's Texan IIs, then these wouldn't be included in that category.
spacecadet 3y ago
How many planes you ship built by you? lol To this commenters point, my uncle has built several Cessna 170's from nothing in his garage... but he also worked in aviation.

fargle 3y ago

It's absolutely not easy to build an airplane. It's incredibly difficult to build an airplane, especially a completely new design. It's absolutely impossible to do that at the same time as making one that will last 30-50 years and have a low failure rate. What is difficult, incredibly expensive, and very time-consuming, but possible - barely - is starting with the first airplane and eventually getting to the second. The first is the job of a Skunk Works. The second is the job of more traditional aerospace organizations.

wiz21c 3y ago
I'm not in airplane engineering, so: > It's incredibly difficult to build an airplane, especially a completely new design. why ?
- snovv_crash 3y ago
  Aerodynamics. Structural design. Design for manufacturing and assembly. Power and drivetrain. Control systems and actuators. Avionics. And then get all of these to a reliability level where you feel comfortable with a single failure causing high likelihood of multiple human deaths.
- intotheabyss 3y ago
  As someone who is in airplane engineering, the biggest barrier today to building a new aircraft is regulations. But if we completely ignored regulations, and you were building a mostly aluminum aircraft with analog avionics and the goal was just to get it to fly (nevermind things like designing for fatigue), then no it wouldn't be that difficult conceptually on paper. However, manufacturing would still be the bottleneck, and that is still challenging today (tolerances, QA, technical expertise). However, if you were designing and building a new aircraft to meet the latest Part 25 regulations for passenger transport, it's almost insurmountable. There's a reason why there are so few aircraft OEMs.
  - tonyarkles 3y ago
    And to go along with it for Part 25, you're pretty much guaranteed to be doing something "thinking outside the box" if you're doing a clean-sheet design, because the current models (737 Max8, A320, etc) are all pretty darned close to their local optima. No one's going to do a clean-sheet design for 5% more pax and 5% less fuel burn, they're just going to riff on something that already has type approval so that a good chunk of the regulatory burden is already mostly taken care of.
- fargle 3y ago
  I agree with the sibling comments, but let me add a few ideas. Let's not even worry about the bureaucracy, safety regulations, etc. for a "Skunk Works" phase. The safety and reliability stuff is even harder, but just the first phase of building anything that flies is really hard. Aircraft design requires truly careful engineering. There is very little leeway. EVERYTHING is a trade-off. You have huge forces and need very light weight. You add a pound of structure to tolerate the loads, now you have more loads and need more power all of which adds weight, requiring more fuel to make range. All of that requires more structure, which adds weight. To find a workable design that "closes" is hard because there is a very small corner of the design envelope that will even work. It's also hard because when working at these extremes of what is even possible, there is no room for failure and you can't just add reliability by brute force (adding more power, more metal, etc.). There are fine margins because you can't afford thick ones. And to live with these fine margins, you must have extremely tight manufacturing tolerances and predictable performance. Aircraft are also a very complicated system. The physics are complicated, the behavior of all the required subsystems is complicated. So now, you have to do the most precise careful engineering you can think of, across a set of super complicated interdependent systems. So all of this costs a lot of money, and at some point - for a new design - it has to take off for the first time. At that point, basically nothing can go wrong. You can't exactly fire up gdb, find the bug and recompile. There is no edit-compile-test cycle (well, or it's a very short cycle). The only thing that seems harder is rocket design. Actually turbo-pump design for the engines for the rockets.
  - wiz21c 3y ago
    ok I see but at the same time, I guess there is a ton of knowledge about previous planes floating around. You don't do it from scratch, do you ? Processor are really hard to do, as well as software for physics simulation, as well as a ton of other things. But for both of them, I can confidently say that nobody starts from scratch: it's improvements upon improvements and from time to time, a bit of breakthrough... I do understand that the safety aspect is pretty specific and really tough to get right.
    - fargle 3y ago
KeplerBoy 3y ago
It's not that hard. Slap a motor and a few servos on a piece of cardboard and you've got yourself a model airplane. Sometimes I'm surprised how easy it is to get something flying.
- SketchySeaBeast 3y ago
  print('Hello world!') Man, I don't know why anyone says that software development is hard.
  - intelVISA 3y ago
    excuse me where's the semi-colon? Unshippable!!
    - opan 3y ago
      It's valid python3.
- tonyarkles 3y ago
  You're unfortunately getting downvoted but you're totally right. https://store.flitetest.com/park-flyers-swappables/ https://store.flitetest.com/park-flyers-swappables/ I work in the UAS industry and we absolutely do use things like these cardboard airframes for prototyping. They're awesome out of the box and really easy to repair with some tape and hot-melt glue if necessary.

vikramkr 3y ago

I have no idea what point you're trying to make - and also it definitely isn't easy to build an airplane. R&D, prototyping, and manufacturing are all hard

whalesalad 3y ago
When you look at what the skunk works were doing back in the day with drafting tables and plywood you would also think it’s easy. These days less so due to electronic/computer driven flight surfaces and all the crazy sensing

shakow 3y ago

> It’s hard to build one that lasts 30-50 years Like the U-2, the SR-71, or the F-117?

dotancohen 3y ago
The U-2 is still flying, even though it was expected to be obsolete quickly. The SR-71 and F-117 are no longer operational, I think they both were retired before 30 years of service. Military aircraft lifespans rarely fit their projected timeframes.
- _djo_ 3y ago
  The F-117s are technically still operational, even after their official retirement. https://www.thedrive.com/the-war-zone/retired-f-117-nighthawks-may-fly-for-another-decade https://www.thedrive.com/the-war-zone/retired-f-117-nighthaw...
  - hef19898 3y ago
    Flying is dofferent from being operational in the military sense. Still impressive that those bird are still airworzhy so.
    - _djo_ 3y ago
      They're still operational systems in the military sense, just no longer front line combat assets. They've been relegated to R&D & training.
      - hef19898 3y ago
        So they no longer have operational capabilitied for their initially intended role.
        _djo_ 3y ago
        Yes, but this is splitting hairs a bit. Are training systems considered operational? It depends. In a systems readiness point of view, yes, they're operational even if they've been re-roled, as opposed to being withdrawn-from-use or having another status. But if you consider only front-line combat systems operational and exclude all other aircraft including training aircraft like the USAF's Texan IIs, then these wouldn't be included in that category.

spacecadet 3y ago

How many planes you ship built by you? lol To this commenters point, my uncle has built several Cessna 170's from nothing in his garage... but he also worked in aviation.