PPRuNe Forums - View Single Post - F-35 Cancelled, then what ?
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Old 17th Nov 2010, 20:57
  #88 (permalink)  
ORAC
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Sorry, that's it. The F-35B is history, the USF wants to restart production of the F-22 in place of the F-35A and Navy prefers the F-18E/F/G on price to the F-35C to be able to man their carriers.

With the price going through the roof as they cancel, no overseas customers will want to take up their options anyway.


Major F-35B Component Cracks In Fatigue Test


The aft bulkhead of the F-35B BH-1 fatigue-test specimen has developed cracks after 1,500 hours of durability testing, Ares has learned. This is less than one-tenth of the planned fatigue test program, which is designed to prove an 8,000-hour airframe life with a safety factor of two. The bulkhead design was modified in the course of the jet's weight-saving redesign in 2004-05, switching from forged titanium - proven on the F-22 - to a new aluminum forging process developed by Alcoa.

According to Lockheed Martin,"the cracks were discovered during a special inspection when a test engineer discovered an anomaly." The company says that flight-test aircraft have been inspected and found crack-free and that flight testing has not been affected.

Engineers are still investigating the failure and it is not yet known whether the cracks reflect a design fault, a test problem (for example, a condition on the rig that does not reproduce design conditions) or a faulty part. If the bulkhead design is found to be at fault, it will be a serious setback for the F-35B program, potentially imposing flight restrictions on aircraft already in the pipeline or requiring expensive changes on the assembly line.

Six F-35Bs are included in the LRIP-2 contract, now in the mate or final assembly stage, and nine in the 17-aircraft LRIP-3 batch - which are intended to support initial Marine Corps training and operations. If a redesign is necessary it could also delay deliveries of LRIP-4 aircraft.

Bulkheads are a major structural component of the F-35, carrying the major spanwise bending loads on the aircraft. They are produced from forgings weighing thousands of pounds, which are machined into the final shape. They are among the longest lead-time items in the airframe, being built into mid-body sections produced by Northrop Grumman.

The F-35A and F-35C bulkheads are still made of titanium, as are similar bulkheads on the F-22.
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