South Pole Diaries 2001/02

   

   


Sunday 21st January

From John Storey.....

Well, I've been here a week. I'm fully acclimatised and I've completely recovered from the Scott's Hut Race. Now, if only the Stirling engine would work properly...

The engine needs to keep its glycol coolant at around 60 C. It does this by controlling the speed of some fans that blow air through the radiator. While the engine we had for testing at UNSW did this very well, our present engine - which is brand new - refuses to even recognize that it has a role to play here. The voltage that is supposed to change in appropriate ways remains resolutely fixed at zero. In short, this engine is completely abdicating all responsibility for its coolant temperature - which leaves us
with a bit of a problem.

So first thing this morning Duane and I did a bit of a brainstorm and came up with the following: if we set the fans up at a constant speed, then for a given amount of heat to be removed from the glycol there will be a constant temperature difference between the glycol and the room air. If we now set the room air temperature to a fixed value, then the glycol temperature will be stable too. Now, as it turns out, the amount of heat to be removed varies, which would tend to cast doubt on the feasibility of the above. But, Duane's measurements in the lab show it varies remarkably little, so we're in with a chance. And, keeping the room temperature constant is a snap, because we have a Eurotherm PID temperature controller that is so smart it could probably beat the Stirling engine at chess. However, I'll tell you about that tomorrow.

While I wired up all the fans I could find (I've called the assembly "the fan club"), Duane did what he likes doing best which is to cut another big hole in the AASTO with a motorised device that looked like a prop from Mad Max III. After lunch (you always have to walk back to the Dome and have a meal before you do anything exciting) we fired the system up and it all worked perfectly. Duane positioned ducts and vents to best effect, and took enough notes for at least two chapters of his thesis.

Just when it was all looking so good, the Stirling engine demonstrated another couple of infelicities. First, it seems determined to avoid all the usual niceties of battery management and is ruthlessly attempting to charge our batteries to death. Second, it is running flat out the whole time, as if it has not yet grasped the idea that it has to make that tank of JP-8 last the whole winter. At this point I'm not sure if we're going to be able to sort all this out. The manufacturers in New Zealand are doing all they can - including bringing a new set of electronics to the Antarctic Centre in Christchurch for urgent delivery to us, but flights to McMurdo were canceled today because of bad weather, and we may not be able to get the parts here in time.

Meanwhile Tony was getting ready to depart, and was clearly not happy to go. However despite a frustrating week with the Supervisor computer, he had ended up with a final triumph: - skua-ing a computer to act as an interface between the Stirling engine and the outside world. In the afternoon, after Tony had left, Duane and I hooked it up. Not only do we get a pretty screen that looks like an economist's view of a Stirling engine and has all kinds of useful numbers on it, but with luck we'll be able to relay all the information back to UNSW during the year.

Over lunch had Tony tutored me in the ways of the Supervisor computer, as I reluctantly accepted the stark reality that I was next in line to go toe-to-toe with this brute. I decided to start back at square one. Once the Stirling engine was purring away, I retrieved the original Supervisor computer and fired it up. It immediately complained that the keyboard was missing and suggested I press F1 to continue - completely overlooking the fact that this would be really hard to do without a keyboard. Do I loath PCs! Of course the keyboard was there all along but just wasn't working. No second chances - straight into the "construction debris" bin (a sort of catch-all category for things that can't be recycled or put to good use). That meant heading off to find another keyboard, which I did but it had a different sort of plug on it, leading to a further hunt in which I finally found another one with the right sort of plug stashed behind the liquid nitrogen plant.

Success! This is where we were ten days ago. Next I had to take all the little boards out of the original computer and put them in the new computer, because the old computer isn't compatible with the new Flash disk and the boards in the new computer aren't compatible with the existing software, etc. This is what PCs are all about. The word "compatible" can mean different things in different contexts; to Microsoft it appears to mean "manufactured on the same planet".

So now we were ready for the big test. For some reason it hadn't worked for Tony; I think he is altogether too patient, gentle and charming to face a PC on its own terms. I took a different approach. Something about my demeanor told the computer that it was going to work first time or it would be into the Construction Debris in less time than it takes a G4 to add 2 + 2. Anyway, while I have not the foggiest notion why, it all seemed to work just fine. It even allows us to telnet to it.

Tomorrow morning the marathon will begin. Assuming they can chug along at 10 km/hr or so, the runners should arrive at the finish line outside the AASTO at around midnight Sydney time. For the benefit of our webcam devotees I have steered the webcam around so it is pointing at the finish
line. Personally I wouldn't cross the road to see it, but if I can watch them from the shower it could be fun.

John

Coming Soon!

 

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