Major F-35B Component Cracks In Fatigue Test

[bhramos]

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.

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.

Correction: Northrop Grumman asks us to point out that the parts in question are built into the wing/centersection assembly made by Lockheed Martin.

http://www.aviationweek.com/aw/blog...&plckScript=blogScript&plckElementId=blogDest

 

[Tshering22]

Looks like F-35 and Tejas have something similar eh?

Both end up getting delayed and developing last minute complications despite being a generation apart.

 

[bhramos]

Looks like F-35 and Tejas have something similar eh?

Both end up getting delayed and developing last minute complications despite being a generation apart.

Basically it has become over fat. it needs to reduce its weight........

some members view

It depends who you are, if you're LM or an investor in them this is certainly a concern but if you're just a taxpaying citizen I think it might be a good thing for LM to take a hit to it's reputation and lose all the associated sales with the JSF project from other nations. The reason for this is that I don't right now LM rightfully thinks that between the lobbyists, already sunk costs and the lack of easy replacement for the project they'll never lose the contract for developing and producing the F-35.

As such I think they've refused to make efforts to reduce their risk of something like this happening because a longer development time-frame means more money for them, increased costs is also more money for them, everything that goes wrong with the F-35 but that dosen't result in the project being cancelled lines the pockets of the CEOs and investors. If they lost the contract and were unlikly to be selected for the next fighter project, they might rethink their approach and stop messing around but as is they have every incentive to screw around on this project because they don't think anything bad will happen to them.

By comparison we can see that Sukhoi can develop planes for a fraction of the price, having spent 10 billion to develop the Pak Fa versus 25 billion for the F-35, considering that the Pak Fa has many more technologies that are new to Russian design then the F-35 has to US design this is a damning comparison.* Now certainly some of this has to do with differing currency values and pay grades in the respective countries but I firmly believe that it's also got to do with Sukhoi having to pay part of the development costs. In paying into the development costs of the program Sukhoi's now invested in it's success and the better it does the more of a return Sukhoi gets out of it's investment. As a result we see them testing engines and cockpit designs in Su-27s for implementation in the Pak Fa assuring that when everything's integrated there will be less uncertainty as to how the components will function.

To be clear I don't think this is because Sukhoi is a better company then LM simply they've got incentives to make them produce as effective an aircraft as possible for as cheap as possible where LM has so many garunteed purchaces that it can fritter away time and money in development with little cost to itself.

*The Pak Fa project is the first one to incorperate stealth, super-cruise capacity, AESA radar and likly some other things I'm missing. The F-35 by comparison builds on the F-22 program's developments for the most part while adding a helmet and infrared/nightvision sigh

 

[Godless-Kafir]

We dont know even if the Pak-Fa is stealthy or not, they may have just built an conventional airframe to convince us to spend money on it. The rear of the aircraft looks right of the Su-30 and its all metal.

This problem with F-35 does not seem to be a big one, they need to go back to their original Titanium based bulk head which i am sure they will do.