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Web Site www.ddsc.org.au OR www.gogliding.org.auddsc-chaotic.blogspot.com

Chaotic Darling Downs Soaring Club

Editor: Dave Holbrook [email protected] 0403948944

April 2010

A short edi+on at present, by the +me I get to

the end, who knows

In this edi*on:

Omarama wave ying

GUSS weekend Pictures

Cloud forma


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with experienced mountain pilots is that I yfurther away than I would being by myself.And ying together is so much fun, we alwayshave a ball! When we're getting low, we focuson the job of nding lift again. Once we'reclimbing again, the jokes and chatting come back too!

Her world record gain of height of 10,212mwhere she ew to 11,312m (37,114ft) to achievethis has not been broken yet. Jo and Jenny,consider breaking that record. That could beyour challenge and inspiration to come over!!

Flying in wave.Flying in wave is one of life's best experiencesin my humble opinion. It can take a while toconnect with the wave. Sometimes it takes afew hours of patiently working thermals or themountain ridges before the bottom layer of thewave is reached. Or the rotor pushes the glideraround before granted access to the silk roadsof the wave. I compare wave ying withmoving over asilk road. It'sso smooth. No

turbulence, just quietnesswith theneedle of thealtimeter goingcrazy, spinningaround like the needle of a stopwatch.

The acoustic variometer delivers high pitched

tunes of pleasure. 10-17 knots lift for minuteson end.

At times I need to pinch myself to make sure Iam not dreaming. The visibility and view ismagnicent.

Coming from Europe, I was used to seeingcities or industrial (smog!) areas during cross-country ights. Flying over Queensland was adifferent ball game with paddock afterpaddock and silos as turnpoints. Gliding overuninhabited valleys,snow topped mountainsand blue lakes withsometimes limited

outland possibilities ischallenging.

In the rare occasion, the only way to retrieve aglider after an outlanding is by... helicopter! Ihave paid plenty of attention to outlandingstrips on the map, watching thepictures&drawings in a special outlanding

book and by actually ying over them.

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What surprises me most about the south islandof New Zealand is that it is so sparselyinhabited. If the world population is nearly 7 billion people, where are they and why aren'tmore people living in Kiwi land? With the beautiful scenery, all the outdoorsports&hobbies, I expected more people to livein New Zealand. (Shsss keep it quiet - Ed)

Warm clothes shopping before you leaveAustralia.When you come over to taste the gliding overhere, bring warm socks, warm boots and awarm jacket with you. Two weeks ago we wentto 24,000 feet and despite warm clothing, mytoes were freezing cold. It's about -15 to -30degrees Celcius at that altitude. My feet tuckedaway in the nose of the Duo Discus, a singlelayer of socks and my Ozzie R.M. Williams boots didn't do a good insulation job. The nextight I was wearing 2 pairs of socks and thatwas much better. It's funny how having coldtoes can spoil the sheer joy of ying. Glovesaren't really necessary. The cockpit itself staysquite warm with the incoming sun. The canopycan ice up when you're going high, then it's

time to come down again. I am not sureactually how to prevent this ice from formingand still maintain altitude. Mmm.

Backup plans.From Christchurch it is about a 4 hours' driveto Omarama over good roads. Accommodationin all different price ranges: hotel, motel,chalets, and a large camp site with a large and

well-equipped kitchen and showers&toilets block. The gliding season goes from September

to April. If the weather is no good for gliding,consider going for walks in the mountains,shing, visiting Mount Cook, or bungee jumping and other adventurous stuff inQueenstown. I must admit, bungee jumping isnot so spectacular as you think. I have done 2 bungee jumps. The rst one was 43 metersfrom the Kawarau bridge, the second jumpwas from 134 meters from the Nevis Highwire.From a gondula. Another fun thing was doingthe latest thrill-seeking thing: The Nevis Arc.It's a 300 meter swing over a canyon. My brother and I decided to do it being suspendedupside-down. When released, the swing takesyou close over terrain in a canyon. Of coursethere's no way you ever ever hit the ground, a buzz it is!

Gliding over Mount Cook Mount Cook is the highest mountain in NewZealand, reaching a height of 12,316 ft(3754meters).

Of this year's ights, the ight to-and-fromMount Cook was the most memorable. Yvonneand I ew in the Duo Discus. The weather

forecast was for a South-West gale withpredictions for good wave.

I spare you the ne details of the rst part of the ight. By the time we reached Mount Cook at 16,000ft a Canadian glider pilot in a LS4 joined the party. We did a photo shoot.

And boy, amazing pictures were taken from

the two gliders. One of the Intensive Careconsultants printed 10 of them out on quality

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A3 photo paper, I will bring them to DDSCwhen I'll be back in October. Also, I put someof them on Facebook, so if you are on Facebook you can have a look as well.

On the way back an altitude of 24,000feet wasreached. Then, we plummeted in 10 minutes to12,000 feet. Unbelievable. The variometer wasstuck to the bottom corner for a long period.High enough to glide back to Omarama, still ashocker of a drop. A Duo Discus has got a niceglide angle, I have got a lot of respects of theglider pilots who did similar ights in (now)old timer gliders. Before I forget, if you need

nasal prongs for the oxygen system in yourglider for ying over 10,000 feet, I can get them

easily from the hospitals I work at.

Terry Delore's 2500 km. A few weeks ago, Terri Delore gave apresentation about his recent big ight. Worldopen declared distance using up to threeturnpoints - 2,499.2km (with John Kokshoorn)on 13th December, 2009 surpassing theprevious world record held by Klaus Ohlmann by 93km. They took off from Omarama, ewto Ward in Marlborough, back to Clyde, nearAlexandra, and then back up and level withTaihape in the North Island, before turningaround and landing at Omarama - ying for just over 15 hours. Currently he ies anASH25, previously owned by Steve Fossett. Itis the same glider they used for their record breaking ights over the South AmericanAndes a couple of years ago. He often takesclub members up to share his cross countryying skills with them. (Together Mr Fossettand Mr Delore set 11 world records between2002 and 2007 - source NZ Herald: Ed).Additional -Klaus Ohlmann beat the record thenext day ying 2,511.1km and on the 28thDecember took the record to 2,643.2km.

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InvitationMembers of the Canterbury Gliding Club arekeen to have more DDSC pilots glide here,since they enjoyed having us over in 2007.Flying with club rates is very attractive,compared to hiring gliders from the 2commercial gliding operators at Omarama. Ihave fallen in love with Omarama 8 years ago.A love for life. I have enjoyed sharing this withyou now.

In October I will work for CareFlight inBrisbane and will be back at the DDSC. I missthe LS7, the Ventus, beautiful Alice andying friends around in the Grob 103. If allgoes well, I will leave New Zealand with myPPL, which I have to convert to an AustralianPPL. And then getting a tow rating, if the clubstill needs tow pilots.

Combining ying lessons with a full time ICU job is challenging, though achievable I reckon.

I'd love to hear from you and you can ask mequestions about New Zealand any time!

Warm regards,Koert-Jan Schonewille

All pictures by Koert, except the ones with theDuo in them, taken by the Canadian pilot.

GUSS PICS:

Libby took a few pics on the Grifth UniSoaring Soc weekend, I have put a few on thenext page.

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Koert and Yvonne in the Duo near Omarama

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The Physics of thermalsand cloud formation.Robert Hart.

Warm air rises

Thermals form when the sun heatsthe ground and this heats the air incontact with it. This causes a bubbleof air warmer than its surroundingsto form.

When air is heated, its molecules become more energetic (speed up)and they collide more energetically.This causes the average distance between molecules to increase and sothe air becomes less dense. Thismakes the 'bubble' of heated airlighter than the same volume of cooler air surrounding it. Thisdifference in weight between the bubble of warm air and theequivalent bubble of cooler air resultsin a buoyancy force (the Archimedes

principle you learned in school) and

the bubble of warmer air starts torise.

As long as our bubble of air iswarmer than the air around it, the bubble will continue to rise.Air cools as it climbs in a thermal

The pressure of the atmospheredecreases with height. As our bubbleof warm air is not contained inanything, it must be at the same

pressure as the surroundingatmosphere.It turns out that the bestway to model this bubble of rising airis to think of it as never mixing withthe surrounding air: we can think of this bubble as isolated from the airthat surrounds it. Science calls this

sort of isolated process 'adiabatic'.

So as it climbs without mixing withthe cooler surrounding air, the bubble's pressure drops and the bubble expands. This expansionspreads the heat energy in our bubble

over a larger volume and this means

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the temperature falls. The rate atwhich air cools adiabatically is calledthe adiabatic lapse rate which for thelower atmosphere is 3 oC per 1,000ft.

Our bubble will continue to rise aslong as it is warmer than thesurrounding air. Eventually, the bubble will rise and cool adiabaticallyuntil it is the same temperature as thesurrounding air and it stops rising.

Moisture in the air and its energy

The lower atmosphere containssignicant amounts of water in theform of vapour. We feel this moistureas humidity. When the atmosphere isdry, our bodies can cool efciently by

transpiring water through our skinsto evaporate into the air using our body heat as the energy source (weloose heat energy and feel cooler as aresult). When the atmosphere ishumid, sweat builds up on our skinas the atmosphere already contains

much water vapour and cannot

absorb more from us as fast as weproduce it.

It takes energy to change water fromliquid to vapour state about 2.4million Joules per kilogram at oursummer temperatures of about 30 oC.This is enough energy to heat about 8litres of water to boiling point fromtap temperature. So we have to put ina great deal of energy to turn liquidwater into water vapour.

The important point in terms of clouds is that when the water vapourcondenses back to liquid form as thewater droplets that make a cloud, allthat energy is released back into thecloud as heat.

It is this energy (the latent heat of condensation of water) that drivesthunderstorms.

If this does not sound like much,think about this: if a thunderstorm

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drops 5mm of rain on 1 squarekilometer, it has dropped0.005 x 1000 x 1000 = 5,000 m3 or5,000,000 kg of water

As all this water started off as watervapour. When that amount watervapour condensed into rain inside theclouds it released 12 million million Joules of energy. For comparison'ssake, the Hiroshima nuclear bombreleased 84 million million Joules, so

it would only take a thunderstorm of about 7 square km (about 2.65km x2.65km) dropping 5mm of rain (asmall to medium thunderstorm) toequal the energy released by theHiroshima bomb!

A sobering thought when you look atthe next thunderstorm and I hopesufciently sobering to deter youfrom ever going near one in a glider.Cloud formation

Now, returning to our bubble of

warm air; it contains water in the

form or vapour. The amount of watervapour air can hold depends on theair temperature as you can see fromthe chart below.

Water vapour in air at varioustemperatures

Source: Wikipedia Creative CommonsAttribution-Share Alike 3.0 Unported

The red line shows the maximumamount of water vapour that air canhold as temperature varies. This isalso called the saturation line (on thisline the air is saturated as it cannot

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http://creativecommons.org/licenses/by-sa/3.0/http://creativecommons.org/licenses/by-sa/3.0/http://creativecommons.org/licenses/by-sa/3.0/http://creativecommons.org/licenses/by-sa/3.0/


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hold any more water as vapour). If we track down the temperature linefrom any point on the 100% relativehumidity line, we can read thesaturation temperature , also known asthe dew point.

So from this chart, we can see that at35oC and 50% relative humidity (thegreen line on the chart), 1kg of aircontains 20gm of water. We can alsosee that, by tracking leftwards along

the 20gm line until we hit the redsaturation line, 20gm/kg would besaturated at 25 oC.

As our 35oC and 50% relativehumidity bubble of air rises andcools, it can cool to the saturation

(dew point) temperature of 25 oC. Wehave cooled adiabatically 10 oC (at3oC/1,000ft) and so have risen justover 3,000ft wen we reach the dewpoint.

If our bubble of air cools any further,the air cannot hold all the water as

vapour and so some of the vapourcondenses into tiny droplets of liquidwater and we see this as cloud.

The water vapour that condenses toliquid water releases the heat energyused to turn it into vapour and thisrelease of energy results in our bubble of air cooling much slowerthan before at about half the rate inthe lower atmosphere (ie about1.5oC/1,000ft).

This results in our bubble of warm airrising higher than would have beenpossible if it was dry air. If theatmospheric conditions are right andthe bubble contains enough moisture,the bubble can rise to 30,000ft or more

and be part of a thunderstorm.

Thanks to Robert Hart for providingthis; off his websitehttp://the-white-knight-speaks.blogspot.com/

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