Monday 19th October

Yesterday we set wing for sunny Darwin, where the x are hot, and the y are hotter.

(You can substitute your own values for x and y. If you're stumped for a good value for y, I can tell you that it's pretty damn warm inside a solar car.)

This is my fourth World Solar Challenge, and my third with Leeming High School. As usual, we rocked up at the airport, and team leader John Beattie distributed a variety of odd-shaped packages to students to hand carry onto the plane, including two-way radios, cameras, embedded computers, and a spare solar car battery, for which he has had to phone Sydney and get a dangerous goods form.

We fly: thirteen students, one ex-student, three teachers, a principal and me. The captain comes back to chat to us during the flight, to find out what it's all about.

We arrive, and meet another teacher in the gate lounge. He's driven a school bus towing the solar car trailer, complete with solar car, four thousand odd kilometres from Leeming to Darwin. He hands over the keys, and gets on to the plane we've just got off. He'll do the reverse in Adelaide: fly in, meet us, take the keys, and drive back to Perth.

We make a mountain of our luggage, sign rental car forms, transfer the mountain to the bus, commute to our hotel in Darwin, and unload.

Nuna, the team who have won the last three challenges, are already there. We chat. They've been in Darwin five weeks, and have already pranged their car. (It's all better now, though.)

The rest of the day is quiet.

In the morning, John Beattie rises ridiculously early, as is his custom, and goes to get the logistics trailer which contains a wide variety of our supplies and which had been shipped separately.

The rest of us take the school bus to pit 19 at Hidden Valley racetrack. We meet and greet a variety of other teams, and borrow a spanner from Bochum to remove the wheel chocks from our trailer.

We fit the computer and the driver control board and displays into the car, and they all work.

Last time, I fitted the wrong thermistor to the motor. This time, I've made sure that I have the one the manual specifies: a 10k thermistor, negative temperature coefficient. I grovel around exensively under the car, taking the old one off the motor, verifying that the new one really really is negative slope by dipping it into a cold can of soft drink and watching the resistance decrease, soldering the new one on, turning on the motor controller, and discovering that it's still wrong.

It turns out that I did fit the one that the manual specified last time, but the manual is wrong, at least with respect to our particular controller. Our motor controller is one we picked up cheap because it was the manufacturer's prototype. A quick call to the manufacturer elicits a promise to have a look around and see if they can figure out what the right thing is, but given that it's a prototype of a now-obsolete model, I don't hold much hope. So tomorrow we'll probably figure out how to attach a different type of temperature sensor.

To finish the day, we take the car out for a couple of laps, with me in the driver's seat. All works well, except that when I pull back into the pit, I realise that I've left the handbrake on the whole time.

Spot the braincell.

-- Doug Burbidge http://dougburbidge.com/