Mi pare non se ne sia parlato in questo thread, ma un paio di anni fa si sono accorti che il motore del JSF, il PW F135, è troppo grosso per essere trasportato a bordo di una portaerei da parte di un C-2 Greyhound, o di un CH-53 o un V-22...o meglio, nonostante venga smontato in 5 parti, la parte piú grossa non è compatibile con il portello di carico del C-2 e del V-22.e, agganciato al gancio ventrale dello Stallion e dell'Osprey, comporta un autonomia di meno di 300 miglia in buone condizioni meteo..inoltre, sempre le grosse dimensioni e il peso ne impediscono il passaggio da una nave da rifornimento alle attuali portaerei..
The naval variant of the military’s fighter jet of the future arrived at Naval Air Station Patuxent River, Md., on Nov. 6, a development that means the Navy and its industry partners are satisfied that the jet can safely perform basic flight maneuvers and is ready to tackle more demanding tests.
Behind the scenes, however, the Navy is struggling to remedy a significant design oversight that poses a major potential hindrance to its ability to successfully deploy and maintain the F-35C Lightning II, the carrier-based variant of the joint strike fighter: Its powerful single engine, when packed for shipping, is too large to be transported to sea by normal means when replacements are required.
“That is a huge challenge that we currently have right now,” said Capt. Chris Kennedy of the JSF Program Office, answering a flier’s question about JSF engine resupply following a public presentation on the state of the program at the 2010 Tailhook Symposium in September in Reno, Nev. He said the program office is working with the Navy staff and carrier systems planners to solve the problem.
Regular wear and tear, as well as mishaps such as an engine sucking a foreign object off a carrier deck, make the availability of replacement aircraft engines critical. High-tempo combat operations only increase the need. Carriers typically pack spares, but heavy demand can drain those stores, requiring at-sea replenishment.
However, the F-35C’s Pratt & Whitney F135 engine, contained in its Engine Shipping System, is too large for the cargo door on a standard carrier onboard delivery plane and for the V-22 tilt-rotor aircraft, the program office acknowledged in a response to a follow-on query from Navy Times. The engine can be broken down into five component parts, but just its power module and packaging alone won’t fit into the COD or the V-22.
The JSF Program Office says the V-22 Osprey, like the MH-53E helicopter, can externally carry the F135 engine module, the heaviest of the five components, at least 288 miles “in good weather.”
One outside analyst, Jan van Tol of the Center for Strategic and Budgetary Assessments, wondered how the Osprey, in hover mode, could safely lower the module to the flight deck or pick up an out-of-service engine in higher sea states, given the heavy downdraft the aircraft’s 38-foot rotors generate when the engine nacelles are in the vertical position. When so positioned, with the aircraft hovering over the flight deck, the rotor wash can also affect sailors standing nearby – particularly those attaching the load sling, van Tol said. The GAO reported in 2009 that during shipboard exercises, the V-22’s downwash was so severe that in one instance, a sailor was directed to hold in place the sailor serving as the landing guide.
Heat could also be a problem. Depending on the amount of heat generated, sailors involved in sling operations could possibly be forced to wear heat-resistant suits, van Tol said.
Moreover, the Navy has no fleet V-22s and has no plans to acquire them. The Marine Corps flies the MV-22, but the Navy amphibious groups that carry its forces and aircraft to distant shores generally do not operate in the vicinity of carrier strike groups.
The 9,400-pound engine module and transport container also cannot not be transferred from a supply ship to a carrier during underway replenishments — when two ships are sailing side-by-side and connected by supply lines — because, Kennedy said, “It’s too heavy for the unrep station.”
The coming Gerald R. Ford-class carriers will have underway replenishment stations that can handle the load, Kennedy said. But the first Navy F-35 squadrons are scheduled to deploy between 2015 and 2018, when there will be one Ford-class carrier in the fleet. The second won’t be commissioned until four years after the first sets sail. The current Nimitz-class carriers will dominate the fleet until the 2030s.
“You’ve got a very complex aircraft — and there are many, many interesting technologies in this — where it’s tough enough to consider the operational and technological factors,” van Tol said. “But apparently, they’ve not looked as carefully at second- and third-order issues.”
NOT THE FIRST PROBLEM
The JSF program was launched in the mid-1990s; system development and demonstration contracts were awarded to design contract winner Lockheed Martin and engine builder Pratt & Whitney in 2001. The Navy currently plans to buy 680 F-35s, including the “B” short takeoff, vertical landing variant and the “C” carrier variant. It has only one F-35C operational flight test model, operating out of Pax River, according to Lockheed Martin.
The apparently unforeseen engine transportation issue is yet another snag in a controversial program that has seen lagging flight tests, cost overruns and other unannounced concerns — problems laid bare by a Government Accountability Office report released in March. The mounting issues prompted Defense Secretary Robert Gates to fire the program’s top official in February, impose what amounted to a $614 million penalty on Lockheed Martin and order a major restructuring of the program.
The program’s director since May, Vice Adm. David Venlet, recently briefed top Pentagon officials on the program’s status, including “additional issues that are of concern,” Gates spokesman Geoff Morrell said.
Taken together, the problems threaten to further increase program costs and complicate immediate spending plans. The House wants to limit the number of aircraft purchased in fiscal 2011 unless certain performance milestones are met; the Senate Appropriations Committee, citing various concerns with the program, has approved a spending bill that cuts 10 of the 42 jets the Pentagon has requested.
NAVY: ISSUE WITH ALTERNATE, TOO
The resupply issue likely won’t add fuel to the fire still burning in some congressional circles for an alternative JSF engine made by General Electric and Rolls-Royce — one strongly opposed by the Pentagon. That engine would have similar transportability issues.
“The F136 would have similar dimensions and modularity,” said Navy spokeswoman Capt. Cate Mueller.
The F136 would use the same transport system, thus making it unable to fit into a COD or V-22.
Mueller said “multiple options” for transporting spare engines to aircraft carriers are being considered in the discussions referred to by Kennedy, which also involve Marine Corps officials. Solutions being evaluated, she said, include “developing a low-profile engine transport system that would fit in the back of Navy and Marine aircraft; prepositioning spares on [carriers and amphibious ships]; and prepositioned spares located at forward-deployed operational areas that can be quickly transported to ships.”
Officials also are evaluating “the usefulness of existing containers with the V-22, MH-53 and C-2 aircraft,” she said.
A low-profile rail system would allow the engine — which by itself is not too large for the cargo doors of the COD, the MH-53E or the V-22 — or its modules to slide off the trailer and into the aircraft, Mueller said. A separate maintenance transfer trailer would be needed on the carrier for the transferred engine.
As is current practice, commercial carriers would be employed to supplement the military’s ability to transport spares to forward locations, Kennedy said. Planners have also modeled carrier capacity to store additional engine modules, a concept he said is “one of the challenges we’re working today.”
Storage, even on a ship as big as a carrier, is a precious commodity, van Tol pointed out. “The storage was always at a premium, no matter how large the ship was,” said van Tol, a retired Navy captain who commanded three ships, including the amphibious assault ship Essex. “Not only that, you have to be able to store it in such places that the yellow gear — the handling equipment — can actually move the engines around to where the jets are that are [having engines] replaced.”
Carriers carry spares for embarked aircraft with engines that are repairable underway. A carrier typically deploys with about 35 spare, fully assembled F404 or F414 engines for its Hornets and Super Hornets, respectively, according to Lt. Aaron Kakiel, a Naval Air Forces spokesman.
All told, the program’s multiple problems “increase the risk that the program will not be able to deliver the aircraft quantities and capabilities in the time required by the war fighter,” GAO concluded. The Marine Corps wants initial operational capability of the JSF by 2012, with the Air Force and Navy by 2013.
However, Naval Air Systems Command said in 2009 that because of the many unresolved issues with the program, the Marine and Navy goals are “not achievable.” The Pentagon’s Director of Operational Test and Evaluation told GAO that it projects the initial operational testing of the full war-fighting capability of the JSF by mid-2016.
By the time initial operational capability is reached, Mueller said, the F-35C engine resupply issue “will be completely addressed.”
GAO did not raise the engine transportability issue while discussing the program’s logistical challenges, but it found that the Air Force faces a parallel problem: The current integrated support system for its JSF variant is limited in scope and would prohibit two detachments from one squadron simultaneously — another limitation that “will severely affect current operating practices.”
At the current Pentagon estimate of $382 billion, the JSF is the military’s most expensive acquisitions program. Under the Pentagon spending plan for fiscal 2011, each aircraft is projected to cost $112 million — or, when research and development costs are factored in, about $133.6 million in constant fiscal 2010 dollars, according to the Congressional Research Service.
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