... that when gliders compete they carry up to 150 litres of water in tanks inside their wings? The reason, strangely, is to make the glider heavier.
Imagine a child's slide - a high one. Now suppose you had a table tennis ball (feather light) and a billiard ball (much heavier), both of the same diameter. You take them up the steps to the top of the slide, place them side by side at the top of the slope and release them simultaneously.
The heavy billiard ball will accelerate rapidly down the slide and be travelling very fast when it reaches the bottom. It has converted its potential energy (due to its weight and height above the ground) into kinetic energy (speed) and would shoot over the end of the slide and travel quite a distance.
In the meantime, the table tennis ball is trundling slowly down the slope, arriving eventually at the bottom to stop, totally out of energy. It had the same advantage of height but not of weight, thus far less potential energy to convert.
Now replay the scenario with the wind blowing up the slide. Unless the wind was blowing at gale force, the billiard ball would still punch through it, albeit not as fast. The table tennis ball would just blow back up the slope and go nowhere.
That's the principle; a heavy glider will punch through the air losing far less height in the process than a light glider. The down side is that a heavy glider will not climb as fast in a thermal as a light glider. If the day's thermals are strong, the overall advantage is with the heavy glider. If the thermals are weak the lighter glider has the advantage BUT the pilot of the heavy glider has the option of dumping some, or all, of his water ballast to even things up.
Pilots don't want to land with a heavy glider full of excess energy so shortly before the end of a race the pilot operates a 'dump valve' from the cockpit and the tanks empty into the atmosphere. This can look quite spectacular as the water streaming out behind forms a white vapour trail behind the aircraft which may well be flying at over 200 kilometres per hour as the pilot converts all unnecessary height into speed to cross the finish line as soon as possible.
If you don't know, you're not alone. One theory is it was derived from an Aboriginal name but more popular theories are that it came from a place in Scotland or Ireland. Another theory is that it was taken from a poem. The town's name certainly came from Temora Cattle Station which existed long before the town but no one knows why the cattle station was so named.
In the early days the town was renamed Watsonford, probably after some politician, but the townspeople rejected it and thankfully the name reverted to Temora.
. . . that some glider pilots can fly over 1,000 kilometres in a day without an engine? Just how do they do that? Well, solar energy is the answer, though not to power the aircraft in any conventional way. Much simplified, the sun warms the ground, the air near the ground heats up, that warmer air rises in a column called a 'thermal'. The glider pilot uses his skill to locate a thermal and circles within it as it rises.
Because air pressure reduces with altitude, the rising air cools at about 3° Celsius for every thousand feet it rises. Eventually the thermal reaches the same temperature as the surrounding air and it rises no more. This could occur at 2,000 feet or 20,000 feet above the ground, depending on the conditions. And the conditions may change from hour to hour.
If a pilot hopes to fly 1,000 kilometres he must judge precisely when to leave a thermal and move on. He must judge which thermals are worth taking and which are not; thermals begin weakly, reach a peak and then decay. Or they might cycle and regain their former strength.
Not only must the pilot be at one with his aircraft, but also with the air, the clouds and what their height and shape may mean to his flight. As he crosses the terrain below he must understand how changes on the ground ahead will affect the air higher up. Dry ploughed paddocks will generate thermals, green wetlands will not. Smoke from a fire, dust from a farmer working a paddock, or ripples on the surface of dam water will show him the wind direction on the ground and an indication of its strength.
To accomplish such a long flight the glider must have an excellent glide angle and be rigged perfectly. For example, the water ballast (mentioned above) is often carried a little forward of the centre of gravity making the glider a little nose heavy. These days this is countered by a small water tank in the tail, otherwise the aircraft would have to be trimmed with a little 'up elevator'. That would cause drag and reduce the airframe's efficiency.
The very best modern gliders have a glide angle of 60:1. In other words, from a height of one mile (5,280 feet) the glider could fly for 60 miles through still air before touching the ground. In theory.
To accomplish a thousand kilometre flight a pilot needs to be almost fanatical about his sport and possess an intuition about weather and atmospheric conditions that most of us will never understand.
One thousand kilometre flights have been achieved on several occasions in Australia. All that distance on energy from the sun, ninety three million miles away. And it's a race against the clock, for once the sun sets, the energy supply will go with it.
On December the fourth we celebrated the seventh anniversary of leaving Perth to explore this wondrous continent; seven years of trepidation (initially), excitement, awe, curiosity, amazement, sadness at the history that is being lost, despair at the behaviour of our political leaders, but above all, gratitude that we live in what must surely be the most friendly, beautiful place on earth.
In seven years of travelling this enormous land we have encountered no problems from the indigenous population or anyone else. Only once have we 'mislaid' anything and that was a new blouse of Pam's that disappeared from a washing line in Cooktown.
We have made some truly fabulous friends and enjoy keeping in touch with all of them and holding reunions whenever an opportunity presents itself - which is surprisingly often.
Let's drink to seven more years.
An invitation from our great friends, Greg and Bev, to visit them in Sydney meant a slight change to our route from Temora to Tamworth. I was very reluctant to take the caravan over the Blue Mountains and into metropolitan Sydney - though we have done both previously - and opted instead to drive to Bathurst, leave the 'van in a caravan park and continue on without it, staying for three days with Greg and Bev. Pam insists we can't go to Sydney without also calling on niece, Amy, and Pam's friend of long standing, Rosalie.
Make it so, she commanded, after the style of Captain Pickard
on Star Trek.
Yes, Ma'am, I replied, snapping to attention.
me up Scotty, we're off to the Big Smoke.
During our three day stay in Sydney with Greg and Bev, Greg decided to have his 57th birthday. What better excuse to eat drink and be merry? Like we need an excuse.
Driving from Warriewood into the centre of Sydney was stressful. We followed Alice's instructions until, about two kilometres after a fork in the road, a very pretty police car with red and blue flashing lights blocked the way and all traffic was ordered to turn around and go back.
It was a very overcast day with rain falling and, as we backtracked, we tried to get Alice to find us an alternative route, but the silly girl kept insisting we should do a U-turn and go back to the police car. After advising her of the deficiencies of her parenthood we continued blindly following the rest of the traffic, a suggestion that Pam put forward, the logic being that these drivers, too, would be seeking an alternate route. However, as intersections were reached, the traffic dispersed in various directions and fresh traffic joined us.
In the end we decided to turn around yet again and try the other fork this time, a suggestion that was endorsed by Alice. If there was any logic in her thinking, it totally escaped me but eventually we arrived at our destination in Surrey Hills where Rosalie, a good friend of Pam, lives.
Surrey Hills conjures up images of lots of space, green grass and trees. In fact, it is close to the Harbour Bridge and full of narrow streets and tall buildings with every available parking space occupied. I dropped Pam off and drove in circles looking for a gap. On the second circuit I found one!
Walking back to Rosalie's apartment in the rain I could hear a muffled voice telling me to take the first exit at the next roundabout. Alice, snug and dry in my shirt pocket, was being as helpful as ever.
Rosalie was as lovely as ever and her little son, Felix, and baby daughter, Maggie are really charming. Kent, her husband was at work, unfortunately. We spent about an hour with them before having to leave to pick up our niece, Amy, who is working in the Opera House and wanted to treat us to lunch there.
Once again, navigating around the city was a nightmare, especially as a GPS has great difficulty differentiating between the road over the ANZAC Bridge and the road vertically under it. So we crossed the bridge, then crossed back. Ho-hum.
Previous research on Google Earth had enabled me to give Alice co-ordinates that placed us right outside Amy's apartment block, as it had outside Rosalie's. However, the same problem faced us again - no parking spots within sight. So again Pam disembarked. This time I sat in the car in a No Stopping zone and watched for anyone in uniform so that I could drive off before he/she got close enough to place an invitation to donate under my wiper blade, but I was lucky.
As Amy guided us towards the Opera House she explained that Sydney was really quite easy to negotiate, it's just a grid. Find George Street first and the rest is a doddle. Thanks, Amy. I expect it does look like that from a bus window.
Amy bought us a very nice lunch in the restaurant at which she works beneath the Opera House and then we walked up some steps for a close-up view.
Our journey home (to Bathurst) was more of the same. Everything on the M2 Motorway came to a standstill and Alice advised us that there was an accident ahead. We took the next exit and then had no idea where we were or which way we should be heading. Naturally Alice exhorted us to go back to the M2 but we ignored her and went to Plan B which was Pam and a paper map.
The idea became, "Head for Katoomba" so I mentioned to Alice that we'd like to go that way if it wasn't too much trouble and she obliged. Just before we arrived in Katoomba we modified our destination to "Home" and she took us right to our caravan in Bathurst.
Next morning there was a lot of aircraft noise and glider after glider was towed overhead and released. This went on for most of the day. And yes, I took a couple of photos, but I promised you not to print them here.
Named after British Colonial Secretary, Lord Bathurst, this city was the first inland settlement to be built in Australia. Why that should be significant beats me. It does mean that there are plenty of old buildings and a bit of history here. For the first week or so we explored no further than Woolworths and Dan Murphy's discount liquor store because of the bad weather and our Sydney visit. As a result we had formed a somewhat myopic and erroneous impression of the place. Pam, the Tour Director, ploughed through the tourist literature and organised a few days of sightseeing.
Day One saw us start our tour by visiting the railway cottage once occupied by Ben Chifley. Who? I hear 99% of non-Australians (and probably 55% of Australians) asking. Apart from being a train driver ...
... Joseph Benedict Chifley, 1885-1951, was the 16th Prime Minister of Australia. He took over the Australian Labor Party leadership and Prime Ministership after the death of John Curtin in 1945, and went on to retain government at the 1946 election, before being defeated at the 1949 election.
Thank you, Wikepedia. The cottage in which JBC lived told us nothing about him as we couldn't get access. The plaques around the place gave the impression that he was a wonderful man, loved by everyone. Research on the internet reveals he was as human as the rest of us.
Chifley had lived apart from his wife for many years: his secretary, Phyllis Donnelly, was with him when he died. Long-held suspicions that she had been his lover were confirmed in David Day's 2001 biography.
Thanks again, Wikepedia.
So there you have just a little of Ben Chifley.
Our next attraction was Mount Panorama, for today Bathurst is best known for motorsport. The Mount Panorama motor racing circuit hosts the Bathurst 12 Hour motor race each February, the Bathurst Motor Festival every Easter, and the Bathurst 1000 motor race each October. However, just as when we visited the Phillip Island racing circuit, it was just a quiet road with normal suburban speed limits applying. We drove around it to the top of the 'Mount'.
There were several residential properties around the circuit and we wondered what happened to the residents during practise and race days. It appears that they rent out their homes for very tasty figures and have an all-expenses-paid weekend away. Alternatively, according to the lady in the shop in the National Motor Museum which is part of the Mount Panorama complex, most residents have access to a tunnel under the mountain through which they can drive to reach the outside world.
The Museum itself was very interesting and we - well, I - spent ages inspecting the cars and motorcycles exhibited.
More of Bathurst on the following page.
Footnote: This re-working of Page 157 was completed on 6 April 2013. It conforms to HTML5 and CSS level 3.