tag:blogger.com,1999:blog-39330614709729633792024-03-13T22:30:31.019-07:00Virtual WirrawayThe creation of a 3D virtual Wirraway aircraft.Anonymoushttp://www.blogger.com/profile/06811490501507172228noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-3933061470972963379.post-29507180786237070352012-09-06T06:10:00.004-07:002014-02-04T12:05:56.888-08:00Starting with the frame<div dir="ltr" style="text-align: left;" trbidi="on">
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<span style="line-height: 107%;"><span style="font-family: Trebuchet MS, sans-serif;">The
Wirraway is constructed around a welded chrome-molybdenum steel allow tube
framework, so that’s where I need to start as well. Here is what the steel tube
framework looks like:</span></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZNpD7h0SuHUy8wq9jxgytqx1QVFsEdK_AfLPyEVhLjaA7ndJhyphenhyphen9-n4h4N8fGP6EfylKjboMmljXaC8LRnAu61yGUGKufTYZ_WhWZt9YgPDM7rVZ5fumrTb_OgfCAKl7rDqawUl6ki9wrc/s1600/31+frame+actual+01.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Trebuchet MS, sans-serif;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZNpD7h0SuHUy8wq9jxgytqx1QVFsEdK_AfLPyEVhLjaA7ndJhyphenhyphen9-n4h4N8fGP6EfylKjboMmljXaC8LRnAu61yGUGKufTYZ_WhWZt9YgPDM7rVZ5fumrTb_OgfCAKl7rDqawUl6ki9wrc/s400/31+frame+actual+01.jpg" height="251" width="400" /></span></a></div>
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<span style="font-family: Trebuchet MS, sans-serif;">The dimensions for each of the tubular members (length, outer diameter and gauge) are listed in the Wirraway Overhaul and Repair manual, so this will be the data I use to create the virtual framework. The fuselage frame is divided into four sections:</span></div>
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<li><span style="font-family: Trebuchet MS, sans-serif;">Main frame</span></li>
<li><span style="font-family: Trebuchet MS, sans-serif;">Aft fuselage frame</span></li>
<li><span style="font-family: Trebuchet MS, sans-serif;">Engine mount (not shown in the picture above), and</span></li>
<li><span style="font-family: Trebuchet MS, sans-serif;">Aft fuselage monocoque</span></li>
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<span style="font-family: Trebuchet MS, sans-serif;">Three of these sections are constructed from welded tubes and the fourth is an aluminium sheet monocoque construction. First I will start on the main frame. The fuselage reference line (F.R.L.) or centre-line is 14¾ inches below the top cross-member in this front face, and the thrust line is another 4 inches below the F.R.L. The side frames are 30 inches apart (from the centre of the tubes), and the main frame is 106 ½ inches long from the centre-line of the front verticals to the centre-line of the rear verticals.</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">The diagonal bracing tubes down each side of the main frame are not symmetrical, a fact missed by many scale modellers. On the starboard (right) side of the main frame, the 4 tubes next to the rear seat are angled outwards, to allow the rear seat to pivot so it can face forwards or backwards. In the centre of the main frame, there is a strong roll-over brace to protect the crew in case the aircraft overturns. The starboard side frame is also missing one upper diagonal bracing tube at the very front, to allow for the installation and removal of the magazine for .303 rounds for the front guns. And at the bottom of the main frame below the rear seat there is a heavy structure supporting 2 plates for mounting the seat pivot bearing. </span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">The first step in constructing the frame is to create all the tubes, and the result looks like this:</span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDuMWQ__bVMFWqOI8ER_hpGgO3F8VDlcOJyZAbqThZgqlOwfSTh86xFijGeSr7Qn2tkTmjsnVhS2V8qgWPgkRAuP7ArVEYx0WB3DHkBSxZGtpPjPdKUsB5QX0CXpWBugy_V0jB4YSdYmTN/s1600/31+frame+fwd+01.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Trebuchet MS, sans-serif;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDuMWQ__bVMFWqOI8ER_hpGgO3F8VDlcOJyZAbqThZgqlOwfSTh86xFijGeSr7Qn2tkTmjsnVhS2V8qgWPgkRAuP7ArVEYx0WB3DHkBSxZGtpPjPdKUsB5QX0CXpWBugy_V0jB4YSdYmTN/s400/31+frame+fwd+01.jpg" height="252" width="400" /></span></a></div>
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<span style="font-family: Trebuchet MS, sans-serif;">The next step will be to start adding all the fillets, brackets and attachments which are also welded to this basic structure…</span></div>
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Anonymoushttp://www.blogger.com/profile/06811490501507172228noreply@blogger.com0tag:blogger.com,1999:blog-3933061470972963379.post-62774517042786999662012-08-22T11:45:00.000-07:002012-09-06T06:14:46.714-07:00Building a CAC Wirraway in 3D CAD<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4hseNCpHNPMCP2HBNx2rRhS8Q78dwtF0AxXntl9ScGfIu3iqZEFZ6Xx5wqRXSaJEIqT6X1XdJzx-z31zxdA91pHIQ36TrzxMa6e4JUXBVzp-cD35TyT5PMNPgS606guQiBLKT7OAderRp/s1600/cac_ca-1_wirraway_side.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Trebuchet MS, sans-serif;"><img border="0" height="195" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4hseNCpHNPMCP2HBNx2rRhS8Q78dwtF0AxXntl9ScGfIu3iqZEFZ6Xx5wqRXSaJEIqT6X1XdJzx-z31zxdA91pHIQ36TrzxMa6e4JUXBVzp-cD35TyT5PMNPgS606guQiBLKT7OAderRp/s400/cac_ca-1_wirraway_side.jpg" width="400" /></span></a></div>
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<span style="font-family: Trebuchet MS, sans-serif;">The <a href="http://dbdesignbureau.buckmasterfamily.id.au/cac_files_ca-1.htm">CAC Wirraway</a> was a training and general purpose aircraft built in Australia around the time of World War Two. It was representative of the transition point in aircraft design from "rag and tube" construction to "stressed skin" construction, with different sections of the airframe being made using both methods.</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">This blog will trace the creation of a 3D virtual Wirraway, incorporating all the structure and components of the real aircraft.</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">First, we need to get organised.</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">CAC based the Wirraway on a design which they had licensed from North American Aviation, Inc. - the NA-16-2K.This design was modified according to RAAF requirements with extra capabilities (such as an increased bomb load) plus RAAF standard communications equipment and armament. However much of the structure remained common to the NA-16-2K. The design drawings also remained common and CAC followed the NAA part numbering system, as follows:</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">aa-01xxx General assembly drawings</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">aa-10xxx Wing installation</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-11xxx Wing centre section</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-12xxx Wing outer panel</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-13xxx Wing centre section</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-14xxx Wing outer panel</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">aa-20xxx Empennage installation</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-21xxx Horizontal stabiliser</span></div>
<span style="font-family: Trebuchet MS, sans-serif;"> aa-22xxx Elevator</span><br />
<span style="font-family: Trebuchet MS, sans-serif;"> aa-23xxx Vertical stabiliser (fin)</span><br />
<span style="font-family: Trebuchet MS, sans-serif;"> aa-24xxx Rudder</span><br />
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<span style="font-family: Trebuchet MS, sans-serif;">aa-30xxx Fuselage installation</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-31xxx Fuselage</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-32xxx Engine nacelle</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-33xxx Landing gear</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-34xxx Tail wheel</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">aa-40xxx Power plant installation</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-41xxx Engine assembly</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-42xxx Engine accessories</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-43xxx Engine controls</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-44xxx Propeller</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-45xxx Starting system</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-46xxx Cooling system</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-47xxx Lubricating system</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-48xxx Fuel system</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">aa-50xxx Fixed equipment installation</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-51xxx Instrumentation</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-52xxx Surface controls</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-53xxx Furnishings (seats, etc)</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-54xxx Electrical equipment</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-55xxx Handling gear</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">aa-60xxx Armament installation</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-61xxx Fixed guns</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-62xxx Flexible gun</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-63xxx Bombs</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-65xxx Pyrotechnics (flares)</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-66xxx Gun camera</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">aa-70xxx Auxiliary equipment installation</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-71xxx Communication equipment</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-72xxx Navigation equipment</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;"> aa-73xxx Auxiliary equipment (photographic, safety, tools, etc)</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">Where aa represents the contract (or project) number for the particular aircraft design, as follows:</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">01 - Wirraway Mk I (CA-1)</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">03 - Wirraway Mk II (CA-3)</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">05 - Wirraway Mk II (CA-5)</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">07 - Wirraway Mk II (CA-7)</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">09 - Wirraway Mk II (CA-9)</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">16 - Wirraway Mk III (CA-16)</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">20 - Wirraway Mk III (CA-20)</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">and so on...</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">So I will be following the same organisation for this blog and the parts for my virtual Wirraway. The tags shown on the right side of the blog will refer to the drawing system listed above.</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">Next, we need to decide which model of the aircraft we will replicate. This is relatively easy. The Mk II Wirraway was the most numerous version, and was involved in the most interesting episodes in the Wirraway's service life, so that gets the nod. But unfortunately there are many minor variations within the "Mk II version", depending upon the production contract, as well as which CAC Engineering Changes, RAAF Technical Instructions and RAAF Technical Orders were implemented onto each particular airframe. So I'll start with a generic Mk II aircraft (say a CA-3 production contract) and see where that takes me.</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">I will also need a virtual engine for this virtual Wirraway, and luckily a lot of documentation is available for the <a href="http://www.flickr.com/photos/46332425@N04/sets/72157625357618053/">Pratt & Whitney Wasp R-1340 S1H1-G</a> engine used in the Wirraway.</span></div>
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<span style="font-family: Trebuchet MS, sans-serif;">Stay tuned...</span></div>
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Anonymoushttp://www.blogger.com/profile/06811490501507172228noreply@blogger.com0