Re: General Discussions
Reply #653 –
Longevity that results from a massive maintenance expenditure, a budget item that in Australia is often described as defence's biggest single operating expense. The US DoD budget for conducting R&D into how to tackle corrosion is billion$ of dollars.
I spent five years about twelve years ago doing R&D into techniques just to reduce the corrosion in one part of the rotor assembly of Seahawk helicopters, moving parts made of specific corrosion resistant alloys that have to go through a full $50K rebuild annually due to corrosion, and those parts are built out of the very same alloy that are used in wind turbine rotors.
The archaeological laboratory that I managed processed artefacts recovered from shipwrecks and I learned a little about saltwater corrosion. And that reminds me that the Polly Woodside, launched in 1885, is still afloat. The Polly Woodside, HMCS Sackville and HMS Belfast are kept afloat on the smell of an oily rag. The same is true for HMAS Melbourne and ARA General Belgrano and probably for USS Blue Ridge. HMASs Kanimbla and Manoora were too expensive to keep in service because the fabric of both ships was badly corroded before we bought them. We still got 17 years out of them, less downtime for extensive refits.
Seahawk helicopter rotor assemblies employ cadmium-plated Cr-Mo alloy steel and 2014-T6 aluminium alloy. Wind turbine gearboxes use steel, aluminium or brass.
My oldest brother has post-graduate degrees in metallurgy and physics and was a senior research scientist with Aeronautical Research Laboratories and the Department of Defence. He was a key witness in the Blackhawk enquiry, if your memory goes back that far. He reckons that comparing naval ship or aircraft corrosion with the potential corrosion of wind turbines is like comparing apples and carrots. Of course, then there's the five and half thousand wind turbines in European coastal waters, the first of which was operational in 1991. Thirty years later and those original turbines are still going strong.