This week at Mawson: 17 October 2014

Back in late August Hägglunds K-18 (blue Hägg) decided that it wanted to have a holiday, so whilst in the field one afternoon she failed to start. Prognosis — broken starter. The two diesos were dispatched to replace said starter motor, and two hours after arriving at Rumdoodle the starter motor was replaced… The starter motor wasn’t the problem. The Hägglunds was towed back to station (covered in a previous story), where a busy four days saw the engine and transmission removed to replace the flywheel and then reinstalled.

This was the first time that I have removed an engine from a Hägglunds in anger. The job was made easier with the assistance of my fellow dieso and several others on station. By the end of the first day the engine was almost ready for extraction, with fuel lines and coolant hoses removed, electrical plugs unplugged, and exhaust section removed.

The following morning the four engine mounts and drive shaft were removed, and out came the engine. This is only possible with the assistance of an engine/transmission counter balance lifting rig. Once we got the engine out and on the ground the engine/transmission was split to reveal the ring gear had broken off the flywheel. The spare flywheel was sourced and installed — the transmission/engine were married again. This was the end of day two.

On day three, after a pre-start meeting to discuss the day’s work, it was time to get the engine back in. We got the lift frame installed on the engine, and the fun began. The installation process is very much the same as the removal process, only reversed. To get the engine from the workshop floor to resting on the engine mounts took several hours, after some tight fits and slow-going to avoid damaging anything. We had to watch the hoses and electrical cables — if any were crushed we would potentially need to remove the engine again. Luckily we didn’t have any problems with the installation. The afternoon saw us installing all the hoses and cables, which went without any major problems.

On day four we had to torque up the engine mount’s drive shaft and lastly install the exhaust. We primed the fuel and then crossed the old finger and pushed the start button… Sweet sound of success! We cleaned up the area, put the seats back in place (so that we can drive it without sitting on milk crates), then it was time for a test drive. Not a problem.

Thanks to the entire station for their assistance in completing the repair, in particular Ewan and Chris for driving it at the time. You saved us a whole lot of trouble later on.

Jens
Station Mechanical Supervisor

It has been over six months since we arrived at Mawson station and I have found myself trawling through the pictures that I have taken since getting here. I remember the outgoing chef telling me that the time would fly and to enjoy every minute of it. No sooner it’s a new month and I’m getting out the chip rations than it’s the end of the month, all the chips are gone and I’m getting out the next month’s rations! You look at the date and think to yourself, “where did the last four weeks go?”. The days are starting to get longer and on the walk to work you notice that the blizz tails that were everywhere are starting to melt out and expose the bare rock that has been hidden for the last five months. There are little pools of melt water starting to form on the edges of the sea ice and you can feel the warmth of the sun even though it’s still −19°C.

The longer days mean shorter nights, which is a nice thing, but all this extra sunshine is at the detriment of the Aurora Australis or southern lights. Aurora is the name given to light emitted when the upper atmosphere is hit by energetic charged particles, principally electrons, travelling along magnetic field lines. Energetic electrons impact a gas that then emits light, and this is the same process that operates in a fluorescent tube or neon light. Auroras occur in an oval around the magnetic poles in both hemispheres. The aurora results from the interaction of the solar wind and the earth’s magnetic field. Some energy released in this interaction is transferred to charged particles which travel along the magnetic field lines into both polar regions. The stronger the interaction of the solar wind with the earth’s magnetic field, the more equator-ward the oval of auroral activity extends.

The colours in the aurora result from light (‘photons’) from specific energy level transitions in excited atoms, molecules and ions of the upper atmosphere, returning to their lowest energy state. There are thousands of individual colours in an auroral display, but three are dominant in the visible spectrum: green (the brightest) and red are emitted by oxygen atoms, and violet from a nitrogen molecular ion. The combination of green, red and purple emissions may give aurora a ‘whiteish’ appearance. I personally have only really seen this whiteish and very faint green aurora in the sky, but when you take a picture is when all the colours come out. I have spent many hours outside in −18°C to −25°C temperatures with many layers of clothes on to get that amazing aurora shot. I had one of the other expeditioners give me a few pointers on how to use my camera, and I’m so grateful (who knew that you needed to adjust the focus ring on your camera for a better picture!). So after being armed with this new information about my camera, lets just say that the first hundred or so aurora shots got binned and the next hundred shots made up for it. The way the aurora dances across the inky blue of the night sky is a sight to behold. It is one of the most beautiful things I've been lucky to see since I have been down here. Fingers crossed there will be one tonight.

Lydia Jean Dobromilsky