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- Toni
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- Pridružio: 18 Jun 2008
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Na temu zasto B-52 ostaje a B-1 i B-2 povlace pre njega.
 
Citat:The NPR was released in early February, validating the need for the LRSO and retaining the B-52 as its launch platform for the near future. The B-21 will also be able to carry the LRSO, and the NPR said the missile will ensure the US continues to have a means to strike any target on the globe even after adversary technological advances whittle down the B-21’s stealthiness in the decades to come.
The draft version of the Vector said the B-2 would be retired “no later than 2032” and the B-1 “no later than 2036,” although service officials said those dates may have shifted somewhat since.
“Included in the decision calculus to retire the B-1 and the B-2,” the service said in the draft, is the need to try to maintain a “force-neutral manning structure,” and to do it, it must “harvest manpower billets from the retiring platforms.” Even so, the service sees growth in the bomber fleet from 157 aircraft today to at least 175, in order to provide the capability required by regional commanders, and “some manpower growth is inevitable.”
Keeping all existing fleets and adding the B-21 to them—for a total of 257 aircraft—“is neither fiscally realistic nor desirable,” USAF said in the Vector draft, adding that Global Strike Command “must pursue the optimal bomber force mix.”
Simply shaving down the numbers of each type isn’t effective, the paper said, since it would require keeping all four logistical trains in place, each with its separate people, parts, and vendors. The bomber force today numbers 10,500 operations and maintenance manpower authorizations.
“Enterprise-wide reallocation of money, facilities, and other resources are necessary to facilitate B-21 fielding and ensure the Air Force has a capable and effective future bomber force,” USAF said in the paper. It pegged the cost of modernizing the B-1 and B-2 to keep them capable to 2050 as $38.5 billion, “which is enough money to fund modernization upgrades for the B-52 and help fund bomber base modernization and nuclear infrastructure.”
Upgrading the B-52 to last until 2050 would cost $22 billion, USAF said, but “this figure is offset by $10 billion cost savings from re-engining, which pays for itself in fuel, depot and maintenance costs, and maintenance manpower in the 2040s.”
After the B-1 and B-2 retirements, the Air Force would field a fleet of at least 100 B-21s and 75 B-52s.
The timing also suggests B-21 deliveries will average less than one a month during production. The Air Force has said it plans to have a “usable” asset when the first aircraft is delivered in the mid-2020s. Assuming that production of the new bomber continues until the last B-1B is retired, a production window of 2025-2036 is likely. Dividing 100 bombers over 11 years suggests a rate of about nine aircraft annually.
Former Air Force officials have hinted at such low numbers, explaining the service wasted a lot of money tooling up to produce B-2 bombers at a high rate but then built only 21 airplanes, instead of the planned 132. At less than one B-21 a month, large savings can be reaped in facilitization, manpower, and tooling—although there would likely be offset costs in learning curve and economic quantity materials purchases.
Under the Air Force’s proposal, the 1961/1962-vintage B-52s will receive a number of upgrades and improvements to keep them relevant in a world where they are too radar-reflective to get close to well-defended enemy airspace.
The B-52 extension depends in large part on a plan to re-engine the aircraft with modern power plants. With new engines, the B-52s would never have to stand down for engine overhauls, as the time “on wing” of the new power plants would exceed the planned remaining service for the old bombers.
The B-52s would also be equipped with new standoff weapons allowing them to shoot into enemy territory from well outside the range of enemy air defenses. Among these would be the LRSO, which the Vector identified as the AGM-180/181, a possible reference to the two competing versions being developed by Lockheed Martin and Raytheon.
Goldfein, at the July event, said the new bomber force would be paired with intelligence, surveillance, and reconnaissance assets such as the RQ-4 Global Hawk to shoot targets at long range, yet with high accuracy.
The Bomber Vector draft made no mention of hypersonic missiles or any other wonder weapons that could enhance the B-52’s lethality, although it did say the venerable aircraft would be perfectly fine in operations where enemy air defenses either did not exist or had already been beaten down by other systems.
The Air Force said the decision to retire the B-1 and B-2 instead of the much-older B-52 was based largely on the maintenance track records of the three aircraft. The B-1s and B-2s have lower mission capable rates than the B-52s.
The Vector said the B-52’s aircraft availability has averaged nearly 80 percent over the last five years, while the B-1 and B-2 averaged about 50 percent. In mission capable rates—meaning the aircraft is able to exploit its full range of capabilities, without any non-working systems—the B-52 averaged about 60 percent, while the B-1 averaged around 40 percent and the B-2 about 35 percent. The B-2’s intensive stealth-maintenance requirements drive their overall low MC rate.
The bomber’s MC rates are driven in large part by “vanishing vendor syndrome” situations where components—especially electronics—are no longer made. In the case of the B-2, the fleet is so small—only 20 airplanes—that vendors don’t want to tool up to provide parts in such low quantities.
Other pieces of key gear, such as gyroscopes on the B-2, for example, “are obsolete,” the Vector reported, and maintainers are already making do by cannibalizing parts.
The B-1’s maintenance man hours per flying hour are the worst of the lot, at 74, while the B-2’s performance in this metric is 45. (That figure does not count the hours needed to maintain its low-observable features, coatings, and materials, which the Vector did not state.) The B-52’s MMH/FH rating was 62.
Cost per flying hour was another factor weighing against the younger bombers in USAF’s thinking. Both the B-1 and B-52 averaged about $70,000 per flying hour (USAF did not call out specific numbers, and its charts were not fine-grained)—while the B-2 costs between $110,000 and $150,000 per flying hour to operate. Total ownership costs followed similar curves.
As advanced air defenses proliferate, for the time being, only the B-2 can penetrate them to hold targets at risk worldwide, USAF said. However, that aircraft will “see its technological advantages diminish in the not-too-distant future.” By contrast, the B-21 has been “designed to operate in this highly contested combat environment.” The B-52, despite not having the ability to penetrate, offers a lot of capability through “its high weapons carriage capacity and vast munitions diversity” to be of value either as a standoff platform or in “less challenging environments.” The LRSO will provide “a highly survivable, standoff nuclear weapon capability for the B-52 and B-21.” Some money can be saved by not fitting the B-2 with the LRSO, as had been planned.
http://www.airforcemag.com/MagazineArchive/Pages/2.....-2050.aspx
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