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
 
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