We know that the top deck attachment to the airframe of the helicopter failed. If the fasteners at the front failed first this would cause the airframe to rotate down by the nose relative to the rotor, putting the tail boom in the path of the rotor. In this case a boom strike may have occurred...
The boat has many anodes. I don't believe they offer much protection in the bolt holes themselves because they are mostly sealed (the holes are wet due to damaged faying surfaces) and don't have a clear line of sight to the anode.
Yes, salt water. There are zinc anodes but I don't believe they offer much protection to the bolt threads in the hole. This is also adjacent to the stainless steel nozzle liner. With that said, I am surprised how little corrosion there is on the threads.
They're breaking in the threaded holes. These 3 pieces are from one bolt. The tube are welded on for extraction.
In the batch of bolts I bought, I got the QC check bolt.
I recently asked these questions. I have some 304L SS urea tanks that were welded using backup bars in the tank top. They're also skip welded on the baffles. The assurance is that urea has essentially zero chloride content. Urea isn't as corrosive as most people think. Don't use bare mild steel...
It appears you're using a cylinder liner. MX bike manufacturers stopped using liners in the mid-1980's for a reason. Is there a reason you want to walk so far backwards?
The nozzle has 3 attachment points, two struts and a flange at the top. All 3 points have a history of fastener failures. It's worse on some vessels than others. We have 3 identical vessels now totalling 6 units.
With the flanges and counterbores corroded I cannot guarantee no perpendicularity...
I'm working with a local supplier. They can source custom bolts but I've only given them one week. We're going to install what we can get with some method of sealing for the threads and under the heads and then perimeter weld the flanges. They were welded previously and both the bolts and welds...
I am starting to divest myself from anti-seize. It should be called anti-gall. I find greases provide better seize prevention as they contain more oils that protect surfaces from corrosion. Anti-seize is mostly powdered EP lubricants with a little oil to make them sticky. Avoid the soap...
Yes there is sea water exposure. The flanges and counterbores are corroded so sealing is no longer ideal. There is surprisingly little corrosion on the bolts considering the conditions. I am going to heed MintJulep's advice but cannot find zinc-aluminum flake fasteners on short notice larger...
I think this is an example of the frog and a pot of boiling water. The boat went on charter and when it came back the change was instantly noticeable. All of the other fixtures we have converted are slowly dimming at the same rate but the change is less noticeable due to seeing it every day...
Now that LED fixtures have been common for some time, is anyone else having issues with reduced light output over time? How are you managing or planning for this? Install extra fixtures and dial up the dimmer as they fade? We did a round of newbuild boats that were outfitted with linear LED...
You need to fire it at a high enough temperature to vitrify it. You may be able to do this with a small propane torch considering the small size of your part.
Polypropylene is the least problematic and lowest cost tank type. You will need to prevent temperatures from dropping below 40°F. In my region that's not a problem, even without insulation. Urea is non-conductive so you can't use galvanic or impressed current corrosion protection. The tank needs...
It seems that the best reason to redesign such a flange is to prevent substitution do to specific environmental exposure risks. I don't know that this is substantial enough to be considered a capstone project.
