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Plaprad

UARRSI Vs Slick External Tanks.

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I was reading through the External Tank overhaul book last night and it had a note that external tanks from UARRSI and non-UARRSI aircraft are not interchangeable. I didn't see a reason stated (I was however skimming) and I can't think of anything that would prevent them from working. Does anyone have any idea why you can't swap them around? I've asked around work, but no one even knew that was in the book.

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I know we got a second set of shutoff valves in the outboard tanks...but no clue about external tank differences

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I asked a few guys at work and one mentioned he thinks that the UARRSI birds have different plumbing in the pylon. It's not really the tank itself that's not interchangeable, just the pylon. Haven't had a chance to go through the books a research it yet, but it sounds like a plausible reason to me.

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When the Talons were UARRSI modified we kept the same external tanks

The Combat Talons all had the segmented American Electric external tanks, not the welded Lockheed external tanks. They are both specified to be 1360-gallon tanks, but from the early days the Talons had all tanks stuffed with the polyurethane foam, for anti-slosh and for fire suppresion. It seems the type of foam changed every few years for deterioration, static build-up, etc. The different types of foam had different colors to make it obvious what was in the tanks.

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Interesting, never heard that. I have seen an UARSSI aircraft with a Lockheed external tank under one wing and an American Electric under the other. I'm guessing they are the same part number though?

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Interesting, never heard that. I have seen an UARSSI aircraft with a Lockheed external tank under one wing and an American Electric under the other. I'm guessing they are the same part number though?

The dash 4 indicates that the pylon (box beam) is the same, but the tank part numbers for the Lockheed and American Electric are totally different. I don't know if they have normally been installed mixed or not; my guess would be not. The T.O. has different "useable on" codes for the American Electric tanks.

John

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These tanks were mixed alot we got rid of the Lockheed tanks (solid) 388236-1 and sent them to the bone yard for ease of maintenance and installed100001-300. As you can see the tank T.O. 6J14-2-12-93 does say not to mix them; however, the 1C-130H-4-28-1 makes no distinction. This could be a good AFTO 22 for someone!!

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For the correct term, its the UARRSI birds have Duel Float control shutoff valves as opposed to the standard tank.

As for interchange with normal tanks, they just have to change the internal pluming.

The purpose of the dual float control is that it allows the tank to take fuel almost regardless of aircraft attitude, i.e. a nose up or nose down situation which would cause a normal shutoff valve to close; it still shuts off but the second valve should be in the airspace and still allow refueling. There is a physical location separation between the two valves.

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The purpose of the dual float control is that it allows the tank to take fuel almost regardless of aircraft attitude, i.e. a nose up or nose down situation which would cause a normal shutoff valve to close; it still shuts off but the second valve should be in the airspace and still allow refueling. There is a physical location separation between the two valves.

And any wing up-bending when you're styoopidly heavy...

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