>>593032
>airframes don't have a service life
That statement is so wrong I don't even know where to begin.
Do you even know what airplanes are made from?
That's right, Aluminium. Do you know what's one of the main characteristics of Aluminium? That's right, again: It's fatigue strength is 0.
Do you know what that means?
>airframes don't have a service life
NO YOU FUCKING IMBECILE! Airframes have a very clear set and calculatable service life. They will eventually fail, and without regularly inspecting the airframe for cracks (and replacing the panels that cracked) your plane will fall out of the sky sooner or later.
Maintenance intervals are constantly being adjusted and shifted around. People with a keen eye literally look over every inch of the airframe looking for cracks in the frame, measuring their length (because there are ALWAYS cracks in an airframe. You can't avoid it), and decide if it is critical and needs immediate replacement, or consider it to to be small enough that the plane can go for another few flights before replacing the part. All of this is based on testing and experience. Airbus literally didn't finish testing the fatigue strength of the A380 beofre rolling it out to customers. They had to increase the speed of their testing facility (which is a giant hydraulic system that simulates takeoff, flight and landing forces on the plane over and over again), just to make sure they got ANY numbers to present to the maintenance staff.
>>593052
> We are just starting to see new materials being used but even then the efficiency gain is tiny compared to just re-engining,
Are you pretending to be retarded? Because your shit sounds retarded.
1:1 REPLACING ALUMINIUM WITH FIBER REINFORCED PLASTICS DOESN'T WORK. The fibers will crack and delaminate all over, because fiber reinforced plastics can't take stress from non-fiber-aligned directions.
Simply replacing a part with an identically shaped part made from "black metal" (if that is even possible, because many shapes can't be made out of fiber reinforced plastics) will NOT work. The new parts will break before takeoff. Some parts literally can't be replaced and have and thus planes have an absolute maximum flight hours or max number of takeoffs/landings without a major overhaul.
To use new materials (read: fiber reinforced plastics, which are about as new as the neolithic age, when humans figured out that attaching rocks to sticks using sinew and amber works really well) you have to completely redesign the parts, which leads to you having to redesign all the attachments between the parts, the dimensions of the plane and WHOOPSIEDOO! You got a new fucking plane that has nothing to do with the original, and you literally have to recalculate everything.
"Re-engining" is also utterly retarded. Taking out an old engine and replacing it with a lighter one means that the decrease in lift stress on the wing base due to gravity is vastly reduced.
This is literally Aerospaceengineering 101. The placement of the engines on the wings is carefully calculated. You can't just change their weight without accepting a massive effort.
Using "more efficient" engines means drastically increasing the cost, because the engines are undoubtedly some of the most expensive parts.A slightly more efficient enginesalso cost a fuckton more money, just so you know. Turbine R&D is ridiculously expensive, because to build one prototype you have to manufacture thousands of engine blades. cont.