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.
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.
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.
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.
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.
> I guess there is a ton of knowledge about previous planes floating around. You don't do it from scratch, do you ?
Well, derivative designs bring their own problems. Also a double edged sword. Making significant mods to a complex system is often even more difficult. There's a lot of analogy with software and computing. Take 737-Max for example. Obviously boeing royally screwed that up - but mainly because their business people underestimated the difficulty and tried to patch over it and take short cuts. That itself is a hard problem: a commercial company does eventually have to make a profit.
And yes, absolutely there are new greenfield designs. If you need a Cessna 170, you don't usually start from scratch. But one reason to start from scratch is that you are pushing the envelope even further because of new materials, new requirements, etc. So more problems.
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.
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.
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
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
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.
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.
The SR-71 officially served for about 32 years, although the last few years weren’t very active - there was a retirement followed by a brief comeback IIRC. NASA had one that might have flown a few times after that, I’m not sure.
What led you to believe the U-2 “was expected to be obsolete quickly?” It would be interesting to know who amongst Lockheed and Air Force personnel were right, and wrong, about something like that.
The U-2, being subsonic, was not expected to last long according to one of the books I read, don't ask me which. In addition to being vulnerable to high altitude interceptors, it was difficult to fly as the stall speed was just knots away from Vne. And landing it was an adventure all its own. That said, the airplane found its niche and outlived expectations.
You can see how certain people would think the SR-71 would naturally be a permanent replacement for the U-2. It'll fly at the same extreme height a lot faster, etc. etc. If you're not aware of the enormous operational cost, which is what really killed the blackbird, it seems obvious which one should succeed. (or if it's not your money...)
Every time one of these threads comes up I think I should reread Ben Rich's book, which I read over twenty years ago and gave to a friend about five years ago. It would be interesting to recall his perspective on this. I think he had something in there about how proud they were about keeping the costs of the reactivation and final flights of the SR-71, which were sort of mandated by congress, as low as possible. They were still a lot more expensive than, for example, recent programs to equip the U-2 fleet with more modern avionics.
> The U-2, being subsonic, was not expected to last long according to one of the books I read, don't ask me which
Probably either Skunkworks or Kelly: More than my share of it all. I recall that very soon after shipping the U2, they saw the writing on the wall for its operational limits and started working on the SR71 very soon after. Looking at the timelines, U2 first flight was 1955 and the first discussions for the SR71 were done in 1957 with work beginning in 1958. Powers was shot down in 1960 in his U2.
The B-52 is the real star here. It is the primary reason that I included the word "rarely". For each of these aircraft, though, I could name two dozen types that did not last 30 years in service.
For those interested in this topic, Ben Rich has a book of firsthand account called "Skunk Works" (this is mostly after the Kelly era). I personally found it to be a good read - a mix between government politics, the fight for funding, the culture of shipping, and what worked and what didn't.
Likewise, `Kelly: More than my share of it all` is written by Kelly Johnson & Maggie Smith. Between the two, Skunk Works is better written but I thoroughly enjoyed both.
The thing that most people overlook about "skunk works" is that they were a manufacturing operation. Their planes were very much designed to be used and maintained.
I've worked in teams that were described as "skunk works," though I'm not sure the ones using that term had actually read the book. But a feature of the teams that were successful, was that the people doing the innovative stuff also had a solid understanding of manufacturing and service. The engineers may have been more conservative than their employers were aware.
"This server couldn't prove that it's skunkworks.com; its security certificate is from www.lockheedmartin.com. This may be caused by a misconfiguration or an attacker intercepting your connection."
It does indeed go to lockheedmartin.com but they should fix that?
Technically, yes, but if they are just parking skunkworks.com to prevent others from using it, from a business value perspective it would be hard to justify.
The opposite of the "design by committee" method that resulted in the F-35 disaster. A plane so bad in every imaginable way it was put (and kept) in production purely and reluctantly as a jobs program.
Well when they request 5-6 variants and one is very different, things happen. Idk if it’s as bad as the Bradley fighting vehicle in production.
There was one huge order over many years that cause the continuous production. This doesn’t include variants sold to several other nations.
For the I series: “A senior IAF official said that the F-35's stealth may be partly overcome within 10 years despite a 30 to 40-year service life, thus Israel's insistence on using their own electronic warfare systems”.
43 comments
[ 3.3 ms ] story [ 102 ms ] threadIt'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.
> It's incredibly difficult to build an airplane, especially a completely new design.
why ?
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.
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.
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.
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.
Well, derivative designs bring their own problems. Also a double edged sword. Making significant mods to a complex system is often even more difficult. There's a lot of analogy with software and computing. Take 737-Max for example. Obviously boeing royally screwed that up - but mainly because their business people underestimated the difficulty and tried to patch over it and take short cuts. That itself is a hard problem: a commercial company does eventually have to make a profit.
And yes, absolutely there are new greenfield designs. If you need a Cessna 170, you don't usually start from scratch. But one reason to start from scratch is that you are pushing the envelope even further because of new materials, new requirements, etc. So more problems.
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.
Man, I don't know why anyone says that software development is hard.
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.
Like the U-2, the SR-71, or the F-117?
Military aircraft lifespans rarely fit their projected timeframes.
Still impressive that those bird are still airworzhy so.
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.
What led you to believe the U-2 “was expected to be obsolete quickly?” It would be interesting to know who amongst Lockheed and Air Force personnel were right, and wrong, about something like that.
Every time one of these threads comes up I think I should reread Ben Rich's book, which I read over twenty years ago and gave to a friend about five years ago. It would be interesting to recall his perspective on this. I think he had something in there about how proud they were about keeping the costs of the reactivation and final flights of the SR-71, which were sort of mandated by congress, as low as possible. They were still a lot more expensive than, for example, recent programs to equip the U-2 fleet with more modern avionics.
Probably either Skunkworks or Kelly: More than my share of it all. I recall that very soon after shipping the U2, they saw the writing on the wall for its operational limits and started working on the SR71 very soon after. Looking at the timelines, U2 first flight was 1955 and the first discussions for the SR71 were done in 1957 with work beginning in 1958. Powers was shot down in 1960 in his U2.
To this commenters point, my uncle has built several Cessna 170's from nothing in his garage... but he also worked in aviation.
I've worked in teams that were described as "skunk works," though I'm not sure the ones using that term had actually read the book. But a feature of the teams that were successful, was that the people doing the innovative stuff also had a solid understanding of manufacturing and service. The engineers may have been more conservative than their employers were aware.
Firefox and Edge showed warnings:
"This server couldn't prove that it's skunkworks.com; its security certificate is from www.lockheedmartin.com. This may be caused by a misconfiguration or an attacker intercepting your connection."
It does indeed go to lockheedmartin.com but they should fix that?
Rushing to a PT isn't the key, the key is having a group of people who know how to rush to a prototype and then empowering them to do so.
There was one huge order over many years that cause the continuous production. This doesn’t include variants sold to several other nations.
For the I series: “A senior IAF official said that the F-35's stealth may be partly overcome within 10 years despite a 30 to 40-year service life, thus Israel's insistence on using their own electronic warfare systems”.
The Accidents and notable incidents is an interesting read on https://wikipedia.org/wiki/Lockheed_Martin_F-35_Lightning_II
I do understand it would lose every time to an F-16 in a dogfight, but it would have vaporised that F-16 long before visual range.
Afaics it has more operational capability than the previous generation of warplanes, in ways that matter to military planners.