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Old 20th Mar 2017, 22:02   #21 (permalink)
 
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http://www.southernlubricants.co.uk/...%20Px%2024.pdf
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Old 20th Mar 2017, 23:18   #22 (permalink)
 
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I'd have to guess that the Sunderlands were designed from the ground up to be more tolerant of salt. Things like avoiding contact between dissimilar metals where possible, using more corrosion-resistant alloys, avoiding closed areas of the structure that can trap salt, etc. None of that could completely prevent corrosion, of course. But if it came down to something sprayed on, they could have just loaded the salt in a C-54 and sprayed it afterward (and/or before).
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Old 21st Mar 2017, 14:32   #23 (permalink)
 
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WD40 or any other such product will not have any effects of any kind on the torque values of a fastener that has already been tightened.
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Old 21st Mar 2017, 15:46   #24 (permalink)
 
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It won't make any difference to the torque previously used to tighten the fastener, but it sure as h*ll will reduce the torque needed to release a rusted thread - that's the whole point of penetrating oil (though there are products that do that much better than WD-40).
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Old 21st Mar 2017, 16:52   #25 (permalink)
 
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I was just looking at one of the comment above about being careful where you spray because of torque values. I agree that there are certainly better products than WD40 available.
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Old 21st Mar 2017, 19:48   #26 (permalink)
 
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It can transpire that some of these water dispersants may have an adverse effect on the torque values of a structural fitting with undesirable structural consequences.
If the threaded fastener is disassembled, and the water dispersant liquid allowed to coat the threads before they are torqued. In that situation, the threads must be clean and dry before torquing for assembly. This is because some means of torque measurment require predicable friction during assembly, and the lubricating properties of the water dispersant would result in wrong torque values, and probable over torquing. Otherwise, for assembled and undisturbed fasteners, the water dispersant will not affect correct torquing, if undisturbed.

ACF-50 is a well respected product. I know a salt water seaplane operator who, after much study, has chosen Ardrox AV 15.
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Old 21st Mar 2017, 20:19   #27 (permalink)
 
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Originally Posted by Chu Chu View Post
I'd have to guess that the Sunderlands were designed from the ground up to be more tolerant of salt. Things like avoiding contact between dissimilar metals where possible, using more corrosion-resistant alloys, avoiding closed areas of the structure that can trap salt, etc. None of that could completely prevent corrosion, of course. But if it came down to something sprayed on, they could have just loaded the salt in a C-54 and sprayed it afterward (and/or before).
They might have used magnesium for cathodic protection, much as ships use zinc for the same purpose. However, casting a casual eye over https://en.wikipedia.org/wiki/Galvanic_anode suggests that there's rather more to it than just slapping a few bars of magnesium all over the airframe; there's a risk of hydrogen embrittlement, which would be just as bad for an airframe as salt corrosion.

I recall what a friend told me about the effort to get Apaches operating from RN aircraft carriers; they had to seriously beef up the ships' freshwater generating plant so that they would have enough to wash down the aircraft adequately afterwards. Such as the problems of putting an airframe not designed for maritime operations anywhere near salt water...

Years of bitter experience fighting the rot in airframes put the RN of magnesium alloys for good, and there was much sucking of teeth from the older hands when it was suggested it would be good to fly Apaches from their decks. An old chum of mine used to be a RN photographer, and for yonks his job was taking pictures of hard-to-access recesses of airframes and sending the photos of ugly growths of corrosion back to the factory for assessment. Often as not the assessments came back as "Do not fly. Ever. Again", or words to that effect!

Duxford's just over the way from where I live - I'm now curious to take a look at their Sunderland to see if there's anything obvious! But I suspect that the tricks they used then are pretty much the same as are used these days for carrier aircraft, which are pretty much as you yourself outlined.
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Old 22nd Mar 2017, 03:52   #28 (permalink)
 
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Been a while since any new sea planes have been produced. However, there has been much effort made to improve corrosion protection of aircraft used in marine environments. For example, fasteners removed/re-installed during routine maintenance are made from corrosion resistant alloys like A286 cres or 718 inconel. Aluminum structures are anodized/primed/painted/sealed to provide corrosion protection.
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Old 23rd Mar 2017, 08:14   #29 (permalink)
 
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OT: How are cars (with all their aluminum parts) treated against corrosion by salt on the roads these days?
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Old 25th Mar 2017, 17:47   #30 (permalink)
 
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..........but it was a WD40 equivalent

Careful. It is not generally understood outside the engineering fraternity that such fluids can have adverse effects if sprayed about without engineering consideration and approval.
I thought I had been quite careful John? If you read my full post again I made it quite obvious that I did not know exactly what the substance was. By saying it was a WD40 equivalent, I meant a product that dispersed water and protected against corrosion like WD40 does, NOT that it was actually WD40.

Perhaps I should have used 'type of' or 'sort of' in place of 'equivalent' ?

Whatever the SAR ground crew used that day, (and we are talking about the 1980's here), it was dispensed from about 10L sized cylindrical containers that were pressurised, and the substance was sprayed on through 3' long spray lances.
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Old 28th Mar 2017, 19:36   #31 (permalink)
 
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Extremely VALID Question!!

For those involved with sea-exposed airplanes of any type, this is import. Heck yes. I di not drive a seaplane, but in past decades have 'landed' a few++ on fresh or brackish water. Protecting you airplane (floats or hull, per type) is critical. If one listens with care, the details are included in basic training.
1. After Every water landing, wash or rinse as much as possible.
2. At home, wash even better.
3. Especially with a Wet Hull Airplane, no matter where moored or parked, get it OUT of the water as often as possible, inspect, INSPECT again, and then repair even the hint of a hull defect. Clean and paint the contact surfaces as necessary - and never delay or compromise anything.
4. It may well fly just fine, but if the SOB floods, your 'flying boat' will sink, often faster than you can drain it or get it into the air. How many times have we heard these horrible tails?
5. STCs are available for most, to install an in-flight water dump. Not a bad idea, but make sure that it actually works and that the water hits the dump when CG is correct.
6. Keep it CLEAN! Did I already mention this? That means inside and especially outside. Over ten years, expect to spend a LOT more on cleaning and paint than do most aircraft owners. This expense will vary, but it you park in salt water, expect to clean and repaint every other year - at best.
Aquatic - hull or floats - is great fun. It also requires considerable skill and some extremely serious attention to maintenance.
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