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USAF hoce da povuce 17 komada u pustinju i smanji broj na 45 da sluze do 2030-2036 dok ih sve ne zamene B-21. Usteda bi bila preusmerena na odrzavanje borbeno sposobnim preostalih 45.
-Prosecna starost 32 godine
-Prosecan nalet po zmaju 12 000 sati
Testiraju koliko jos mogu da produze resurs
Citat:The B-1 was designed to fly 8,000 to 10,000 hours, or about 30 years in normal service, depending on the rate of usage, but the fleet has actually flown about 12,000 hours, on average. To help predict where physical failures are likely to occur, the Air Force has, since 2012, run a structural fatigue test on a B-1 carcass and wing taken out of the boneyard at Davis-Monthan Air Force Base, Ariz. In a test apparatus at Boeing’s facilities near Seattle, a series of bars and pulleys apply forces on the wing and fuselage, simulating the effects of multiple flights. This ages the test article faster than the operational fleet and helps engineers discover structural vulnerabilities before they appear in operational aircraft.
The goal, Newberry said, is to achieve 28,000 simulated flight hours on the representative wing, and 27,000 hours on the fuselage; what’s called the “durable life” of the airplane. So far, tests have simulated 15,875 hours on the wing, but just 7,154 hours on the fuselage.
Those hours are actually half of the real numbers, though, because fatigue tests are meant to establish a “Certified Structural Life.” The service is only comfortable flying the fleet to half the number of simulated hours applied to the fatigue test article, to leave a generous margin for the unexpected. Consequently, while the wing taken from the boneyard had 3,085 hours already on it, the structural fatigue test could only be credited 1,547 hours at the outset.
“Unfortunately, we’re behind,” Newberry allowed. “The [actual] fleet average is a little over 12,000 [hours].” The wing test article is ahead of the fleet average, but the fuselage lags it.
The reason the test is behind has to do with the way structural fatigue tests are run. If a structural failure occurs on the test article, the test must be stopped while engineers figure out what broke, and why. A repair is then designed, prototyped, and installed. The fatigue test then continues. When the operational fleet encounters the same problem, a fix is ready to go. Or, it may be installed preventively during depot maintenance.
Major problems that required stopping the test included “on the wing … leading and trailing tabs, upper wing splice bolts, and drain holes,” Newberry said. On the fuselage, it was “(zabranjeno)s … on the dorsal and shoulder longerons.” A repair is now being prototyped on the forward intermediate fuselage. There are also rib (zabranjeno)s, he said, as well as “shearing bolts and tension clips. So there are various items.”
“We want to get ahead of the fleet,” Newberry said, he can’t predict when that will happen, because it’s impossible to know when the next failure will occur. Even now, the test is on hold while a fix to a longeron—a main structural piece that carries heavy loads in the structure—is being prototyped.
https://www.airforcemag.com/article/repairing-broken-bones/
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