Bart Bear's Blog

Labels: engineering, history, New South Wales, train

My Da Vinci catapult is ready for action. It is a slightly modified version of the one designed by my engineering idol, Leonardo Da Vinci, back in the 15th century. The big difference between the Da Vinci catapult and earlier ones is that Leo used the energy of bent wooden beams to power the beast. My small model uses bamboo beams. Here's some photos of the first test shot. Naturally, Scruffy, Milky, Blu and Darcy had to be there to see how it worked. Scruff was the loader because he is the biggest of the others. His ammunition for this test was plasticine balls. Blu and Milky were the plasticine packers and passers-to-the-loader. Darcy and I cranked the beams to max and then I pulled the string that released the ratchet gear. The catapult arm swooshed over, faster than the eye could follow, and from somewhere near the top of the glass doors to the courtyard came a "thunk". Just as well it wasn't a ball bearing or one of Dad's fishing sinkers..... I thought we might get a range of a few metres, but instead the beast throws a 1cm ball of plasticine around 10 metres! Mum has banished catapult practice to the outdoors. Swooping magpies beware!

Labels: engineering, family, heroes

One of the things that I like doing on fine days is to stir the Oldies into taking me for a drive. We just drive around roads and lanes that we haven't been along before and see what's there. Last week we investigated some lanes just east of Canberra in NSW. There are lots of small hobby farms there and on one of their driveways we found this interesting bit of old farm machinery. Dad knew what it is, after all he is almost as old as it. It is a hay-rake that used to be dragged behind a team of horses or a tractor. Great for small bears to climb on, you can see that I managed to get onto the seat. If there had been a horse or a tractor around I would have loved to have a go at raking something. Actually, the only horses we saw on this "lane-cruise" were these two in a paddock near an electricity sub-station. I guess that if they had broken through the fence and touched one of the connectors they would have found another, shocking, meaning of horse-power. (Mum: Apologies for Bart's attempt at a word joke)

Labels: animals, Canberra, climbing, engineering, New South Wales

Today we went for a drive out to the Cotter Dam to see how the work is progressing. You can see how much the dam wall has risen by checking back to my post in November last year. Since November the work had a big holdup. We had lots of rain and the water flooded over the wall and washed lots of machinery and materials away and held up work for weeks. Work is progressing fine now. The new wall is about twice the height of the old dam and it has about as far again to go. One thing that I like is the way that the area in the valley below the dam is being turned into picnic grounds and walking trails. The trail up to the observation platform is an easy one, even for my Oldies. As you can see in the photos, it is being extended to go across the river by a cute little suspension bridge and will take you right up to the dam wall. I watched the truck tipping a load of sand and gravel ready for the next concrete section of the path. As soon as I can walk along it I will post more photos.

Labels: Canberra, dam, engineering

It seems like there is not much in the engineering line that Leonardo DaVinci didn't think of first. Here's another couple of things. The left model is of a ratchet gear to make it easier to lift weights. Just about every windlass and winch since then has used this system. Wind the handle around, the weight goes up.When you let the handle go a stopper slips into the cog teeth and stops the handle whizzing backwards and tossing the small bear off the table.
The gadget on the right is a model of probably the first extension ladder. The design is for a ladder that can extend its length, be raised and lowered, and mounted on a turntable so that it can reach in all directions. It also uses a ratchet gear to stop the moving bit of the ladder falling back when the winding handle is let go. You can see the modern version of this sort of ladder on some of the big fire trucks. Modern versions use hydraulics to do the lifting and extending, and guess who designed the first hydraulic machines? My cobber Leonardo, who I have now included in my list of heroes.

Labels: Canberra, engineering, heroes

Here's another one of the great models of Leonardo Da Vinci's machines in the exhibition at Floriade. This is his version of a tank. Imagine this thing creeping towards your castle or your mob of soldiers. Lots of soldiers inside the tank pushing it along, lots of cannons aiming in all directions, and the whole thing protected from arrows and muskets by layers of sloping wood and leather panels. Of course the section left open on the model would be covered in the real thing. The commander rode on a platform at the top where he could see out and tell the guys which way to push and what cannons to fire. The idea is not so different from modern tanks. No doubt about it, Leonardo was way ahead of his time. You may have noticed that the model is just the right size for a small bear. Now, if I can get Dad interested we could make one of these, put radio control in it and scare the dickens out of stray cats.

Labels: Canberra, engineering, gardens

Last weekend was a long weekend. The weather was not so good, cloudy and showers so obviously the choices were stay in bed or drive somewhere interesting. No choice really, so we made a dam good weekend of it. That is, we went and checked some dams. Now for years the dams in this part of Australia have been getting emptier and emptier. The rain just hasn't been falling. They say it's because of somebody called El Nino. But now things have changed and we are getting skads of rain. The dams are filling up again and the dry old country is looking green. So green that some cows and horses are getting into trouble by eating too much fresh green grass. These are two of the dams we visited. The top one is Burrinjuck Dam, about two hours drive out of Canberra. It was built in 1928 to supply water to the Murrumbidgee Irrigation Area, one of Australia's most important farming areas. The good news is that it is totally full. The drive to the dam gets a bit hairy near the end. The road is narrow and winding and has some steep drops off the edge in places. You can't get any closer to the dam wall than the spot we were at, so you can't see the narrow valley that the dam is built across (of course you can always Google Earth it). All you can see is the control building on the top of the dam wall. The Oldies said "dam" about that. The bottom dam, Googong Dam, is the important one for Canberra because it is where most of the water for Canberra and Queanbeyan is taken from. There are other dams in the Canberra supply system. One of them is being extended right now and I will get pictures of the work soon. Googong was nearly dry last year but now it is around 75% full again. You could walk right across the dam wall the last time we were there, but now there is a lot of construction going on at the spillway on the far side and the dam is fenced off. The Oldies said "dam" about that too.

Labels: Canberra, dam, engineering

The Oldies get really excited about great engineering. On their big trip last year they managed to see lots of the classic structures in the UK, where modern engineering started. This is the world's first major steel bridge, the Forth Rail Bridge near Edinburgh in Scotland. The Oldies had dinner at a great little pub/resseturaunt (I still can't spell restaurant) that is between this bridge and the road bridge, also a spectacular one. Mum was really hyped up and spent most of dinner time counting trains. Forth Bridge was built in the 1880s to carry two tracks of the British North Railway across the Firth of Forth. The bridge is over 2.5 km long and has towers 140m high. The railway is 46m above the high tide level. A real engineering marvel. When the oldies were there the bridge was having some major maintenance done. The big white structures on the towers are supports to make sure that things don't fall apart while the bolts and rivets on the towers are being inspected and replaced if necessary. Trains keep running across the bridge all the time, even when it is being worked on. I think it is a really pretty bridge, I like red.

Labels: engineering, Scotland

Here's Mum at one of the great pieces of engineering the Oldies visited on their big trip. This is part of the Thames Barrier at Woolwich in London. The barrier is there to prevent London being flooded by a combination of high tides and storm surges. To get to the barrier the oldies had to take a long boat trip down the river. I would have enjoyed that, but they left me behind with Unka Paddy. The silver shells house the big motors that raise and lower the floodgates. The gates were all down when the oldies were there. I think it would have been fun if the gates had come up while they were on the outside and locked them out for a while.

Labels: boats, engineering, England

Wind can be useful, as well as being dangerous to sailing ships. On our Great Ocean Road trip we saw two windfarms. They are both on ridges near the coast where the wind from the Roaring Forties hits Victoria and South Australia. This one is at Codrington in Victoria. The other one is near Lake Bonney in South Australia. You can drive right through the Lake Bonney one, but at Codrington you have to be in a tour group. The oldies were very excited by these places. They have often argued that wind power should be used more in Australia. The old arguments that wind turbines make too much noise and are dangerous to birds don't make sense to this small bear. Even standing just about right under a turbine all you hear is a very quiet swoosh. And we saw a flock of crows fly right through a spinning turbine without injury to the crows or the turbine. I guess people think the turbine blades spin fast like aeroplane propellors, but they actually spin quite slowly, even in strong winds. The Codrington windfarm is Mum's favorite. Can you guess why? That's right. Cows. Sometimes I worry about her.

Remember, to see a bigger picture just click on this one. Check my archives out too, to see what I have been doing over the last year.

Labels: engineering, Great Ocean Road, South Australia, trips, windfarm