Fuel interting is ineffective in the aircraft. This device (OBIGGS) is not doing its job.
Here is a good video explaining OBIGGS.
It is unknown how the fix will be performed. It could be one of the things that require a complete redesign.
Interesting words from various studies. There are different amounts of fuel tank inerting needs for various risk situations. Obviously, the one for combat jets is a more demanding requirement:
The U.S. military conducted fuel tank inerting tests and determined the nitrogen inerting
concentration limit was 9% oxygen (91% nitrogen). This limit was based on the threat of small arms fire up to 23-mm high energy incendiary (HEI) rounds. Studies of fuel tank inerting suggest that 86 to 90% nitrogen concentrations are required to prevent arcing ignition.One study indicated 84% nitrogen concentration is required to prevent hot-surface ignition. Another study provides data that suggests 82% nitrogen is sufficient to limit the flammability of methane and air mixtures. The FAA conducted tests to evaluate fuel tank inerting requirements for ground-based fires and found a range of fire protection from 9% oxygen concentrations up to 18% oxygen concentrations.
So, the F-35 can't meet the lower civil requirement for fuel-inerting.
4 comments:
With F35 using fuel as coolant, wonder if the fact that the fuel will be warmer than on other fighters also might pose a problem for inerting?
the hotter the better I suppose. It's gas transfer. The less liquid fuel, the easier it is to pump out tank. (as long as its not too hot, then exploding)
Or are you thinking, the entire plane compartment is so hot, it ruins the membrane/fibers.
So what oxygen concentration does the F-35 OBIGGS generate?
Sorry, what's the source for these issues?
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