/sci/ - Science & Math

>>12705244
Many of the normal passenger planes you still see today were built in the '70s.
>But THEy lOoK no DIFfeRent FRom NeW PlaNES
That's because there's no innovation in aeronautics.

>>12705248
The thing is, i know that most of them have a limit of flying hours before they have to be scraped. I remember that one crash where a part of a plane fuselage broke off because it had surpassed maximum flight hours. Most of the planes i see nowadays are newer than 80's

>>12705244
Do those military planes fly every day like airliners?

>>12705244
They do extensive refits and upgrades.

>>12705248
>there's no innovation in aeronautics
There's no innovation by the greedy jews that took over our aerospace industry. They literally treat R&D as cost overhead. There's lots of innovative academic research though.

>>12705258
Structural fatigue is a thing but from my knowledge, most commercial airplanes serve at 20 to 30 years before they're retired.

>>12705244
Military aircraft typically fly far fewer hours per year than airliners do and get for more maintenance time per flight hour which is why they last so long. That maintenance schedule just isn't economically feasible for the airlines, and things like interior wear and pressurization cycles catch up quickly to airframes in passenger service.

Also, the B-52 can't safely be converted to 4-engined operation because it doesn't have enough rudder authority to make up for losing an outboard engine on takeoff if it only had 4 engines. It needs the redundancy of 8 engines to make up for its tiny rudder. Wing droop on the ground also means fitment for the outboard engines is a tall order since they're heavily limited by diameter. They're about to switch them to newer, more efficient engines.

t. pilot

>>12705271
Thanks for the answer, btw what do you fly/flew?

>>12705248
>Many of the normal passenger planes you still see today were built in the '70s.
Which specifically? Which airframes build in the 70s are still in commercial airline service in America today?

You can find some planes like that still flying in remote Asian shithole countries like Pakistan, but those planes are long out of service in America. There are not many 737-200's still flying at all, and none of them are carrying passengers in America. Is the word "many" in your comment meant to mean "a handful"?

>>12705468
most of the old planes i see flying on civillian use, are used as cargo planes

>>12705553
Yes, there are even still DC-10s used for cargo, and they stopped making those in the late 80s. However the post I responded to claimed
>Many of the normal passenger planes you still see today were built in the '70s.
Where are such planes? Planes built in the 70s and still being used for passengers today? As far as I can tell they don't exist in developed countries, and there aren't "many" of them even in the third world (judged by comparing how many were built and how many are still being flown today, it sure as shit isn't "many".)

>>12705570
Yes you are correct, but how can cargo planes last longer? They also do a lot of flights

>>12705585
They don't last longer. They are permitted to be less safe, since fewer people will die when they crash.

>>12705586
well thats fucking retarded lmao, althought it is true i rarely hear about big cargo planes crashing

>>12705605
More bodies = bigger lawsuits.
It legitimately changes the economics of the situation. An airplane that is economically viable as a cargo plane may not be economically viable as a passenger plane. If in 2021 a DC-10 crashed with 300 passengers on it, lawyers would tear the airline to shreds by questioning why they had 300 passengers on a 30+ year old airplane. The very premise of an airline putting 300 people on such an old plane sounds completely unreasonable to the general public, so the airline would lose the lawsuits and also be ridiculed by the rest of the general public. It would be a PR disaster. At least when a new airplane crashes, it is easier for the public to believe the fault was with the pilot, or the manufacturer, or just a freak accident. But if pilot error kills 300 people on a 30 year old plane, how many people will believe the plane being 30 years old had nothing to do with it?

>>12705632
Yeah you are correct. But shouldn't airliners also be careful with cargo planes? I know that DHL carries Formula 1 cars and other equipment when they change countries between races, so the cargo on some of those planes can easily surpass 1 billion dollars (the cars alone cost around 200 million dollars just to develop, plus all the spare parts and stuff)

>>12705244
Only the crew compartment is pressurized, so the main fuselage doesn't go through the same cycles that limit the fatigue life of an aircraft. Also, it isn't riddled with portholes which furter weaken the structure. Also it's a military plane, made to survive direct hits from missiles, so it's most likely overbuilt. All this mean less stress on each single component, and one way to increase fatigue life is to reduce the stress in the first place. Commercial aircrafts are made to be as light as possible while retaining the bare minimum structural integrity because muh fuel efficiency. Also this >>12705271

>>12705248
>That's because there's no innovation in aeronautics.
Eat a dick asshole, innovation is driven by politics and markets' demand. Politics want a supersonic passenger plane? Here you have Concorde. Market demands the fuckhugest passenger plane to sail the skies for their hub'n'spokes model? Here you have the A380. Then the market says: you know what? People don't really give a shit about any of those things, what they really care about is getting from point A to point B directly in the cheapest way possible, so now everyone's trying to make everything super efficient, which turns out requires a lot of attention to details, which you fucking pleb won't ever notice because you can hardly tell the difference between a Concorde and an A380.

t. AE

>>12705248
>That's because there's no innovation in aeronautics.
There is a ton just not noticeable to plebs like you
>>12705244
The B-52s today are practically a different aircraft in comparison to its original versions. New engines are going to change the way it flies like the 737 max 800

>>12705922
What about the overall frame and stuff? Do they rebuild it entirely on new materials?

>>12706007
No, the airframes are ancient and so are most of the rest of the planes. The avionics and electronic systems are all kept up to date of course, but that's icing on the cake. The airplanes themselves are old but still get the job done.

>>12706190
what about metal fatigue and stuff liek that on the old airframe?

>>12706203
They keep an eye on such things I'm sure, but evidently the airframes are mostly still good for a few more decades.

>>12705244
They've tried to replace the engines before, always ends up being too expensive and they give up

>>12705262
certainly not

>>12706007
Depends on the aircraft but normally no they just make the same frame, these frames are actually really good and updating them wouldn't help much.
>>12706203
They replace the aircraft, it being designed in the 60s doesn't mean it was made then. There are only so many pressurizations an aircraft can take before it has to be retired
>>12706190
>icing on the cake
You could not be more wrong

>>12706259
>>icing on the cake
>You could not be more wrong
As far as air-worthiness is concerned, it is the condition of the airframe, not cutting edge electronics, that is important. The best electronics in the world wouldn't keep a worn out airframe flying, and outdated electronics would not render an airplane unflyable (there are plenty of airworthy antiques out there which prove this.)

Note that air-worthiness is not the same thing as usefulness.

>>12706259
>They replace the aircraft, it being designed in the 60s doesn't mean it was made then.
You're wrong; no B-52 fuselages have been manufactured since the 60s.

>>12706259
>>12706270
> The last production aircraft, B-52H AF Serial No. 61-0040, left the factory on 26 October 1962.

>>12705266
>it’s the jooooooz
Fuck off Americans are the greediest humans on the planet constantly projecting on Jews

>>12706266
> it is the condition of the airframe
And? The condition of the airframe is determined by the amount of pressurizations and the maintenance performed on it. They will last for that long no matter what but new avionics and electrical systems keeps their performance at a level where they are useful to the military.
>and outdated electronics would not render an airplane unflyable
It absolutely can.

>>12706287
America is run by the jews so you're both right

>>12706323
>And? The condition of the airframe is determined by the amount of pressurizations and the maintenance performed on it.
I never suggested otherwise.
>They will last for that long no matter what but new avionics and electrical systems keeps their performance at a level where they are useful to the military.
Not relevant to what I said.

>>and outdated electronics would not render an airplane unflyable
>It absolutely can.
Outdated electronics can render a plain unsuitable for any military mission. But if the airframe and engines are still good, the plane still could fly, hence:
>Note that air-worthiness is not the same thing as usefulness.

>>12706332
>Not relevant to what I said.
Yes it is entirely relevant. We are talking about why they are still in use and the capabilities of the aircraft are what keeps it in service
>Outdated electronics can render a plain unsuitable for any military mission.
No it can destroy a plane's airworthiness, i've seen plenty of aircraft be retired because their electrical systems are so old they're causing too many problems.
>Note that air-worthiness is not the same thing as usefulness.
Both usefulness and airworthiness have a part in the lifespan/service record of an aircraft.

>>12706363
>We are talking about why they are still in use
No. Maybe you were. I was talking about why they are able to fly at all, not why they are still in service.

I hope this clears up our misunderstanding.

>>12706375
>I was talking about why they are able to fly at all, not why they are still in service.
Kind of a weird focus when the OP is talking about length of service commercially compared to militarily.

>>12706381
I didn't respond to OP. I responded to:
> What about the overall frame and stuff? Do they rebuild it entirely on new materials?

>>12705468
Before the pandemic started I was on an AeroMexico flight from Denver to Mexico City that still had ashtrays in the armrests and CRTs mounted above the aisle for showing movies. So I'm guessing that airplane was pretty old but I can't say for sure it was manufactured in the 1970s. Other flights on AeroMexico had seatback screens and were either newer planes or had been renovated. Still, it amazed me to see ashtrays on that first flight.

>>12706406
>AeroMexico
Any of these less wealthy companies are going to fly older airframes

>>12706406
Did you flew on a prop plane? How many seats per row? Trying to find out the plane

>>12706406
Well Mexico is third world or the next thing to it. Countries like Mexico or Pakistan are where you might find these ancient airliners still in service. Though
>CRTs mounted above the aisles
Could date the plane to as late as the 90s or early 00s.
I don't know what the timeline for smoking customs in mexico looks like, but I think that's not strong evidence of a plane being from the 70s either.

Also I don't know exactly when you flew or what planes were in AeroMexico's fleet at the time, but presently their oldest planes are from the 90s at the earliest. (pic related)

>>12706438
I did some more research, apparently they still use 2 ATR-72s

>>12706459
>ATR-72
>Introduction: 27 October 1989
>Status: In production, In service
>The number "72" in its name is derived from the aircraft's standard seating configuration in a passenger-carrying configuration, which could seat 72–78 passengers in a single-class arrangement.

Those planes are no older than the late 80s, and could even be brand new because they're still in production.

>>12706470
but i mean, it's a pretty low cost plane so they might have taken some luxuries away from it

>>12706477
I wouldn't expect a luxurious experience from AeroMexico.

>>12705244
I wonder how /k/ would respond to this thread.

B52s are a Ship of Theseus. The military can afford to fabricate and salvage parts piecemeal. In order to keep a certain number flying.

>>12705244
Because plane wear and tear is mostly related to how many flight cycles they go trough, commercial planes are flying mostly around the clock, some making 10 or more flights a day while military planes aren't. Military planes are also built with bigger tolerances, get maintained more both in terms of day to day repairs but also straight up replacement parts which wouldn't make any sense for a commercial plane. Military planes also don't really need to care about passenger considerations or economics, sure you could salvage a DC-3 and it would still fly today but passengers wouldn't want to fly with it, it wouldn't offer the comforts or services of modern airplanes and the ticket price would be much greater to boot since the maintenance and fuel consumption just isn't what it is with modern planes.

>>12705244
Airlines run a business: they need to make a profit or they die. The biggest cost for airlines is fuel. So it makes sense for airlines to get newer, more efficient airplanes even if they cost a lot because the marginal cost of a newer plane is lower.

Old airplanes are still used for cargo: They're cheap to buy from airlines who can't afford to run them anymore and they can be converted to carry cargo. Cargo airplanes tend to not have high utilization. Passenger airplanes have really high utilization. Because the cargo airplane utilization is lower, the fixed costs (airplane) dominate instead of the variable costs (fuel efficiency)

https://www.youtube.com/watch?v=y3qfeoqErtY

>>12705248
>But THEy lOoK no DIFfeRent FRom NeW PlaNES
why do people suddenly type like this?