Introduction

The CAD class recorded here was held in January & February 2009. This is a class on how to design a scale model airplane in CAD, using 3-view drawings as a starting point. The concepts covered are applicable to designing any model airplane. The course consists of approximately 10 hours of instruction.

Introductory Price: $59.95

If you're interested in taking the class, see the Wings on the Web Store for pricing and availability. The first session (both sections) can be downloaded free of charge for evaluation. Upon payment, you will be given a URL, login and password to access the full course content.

Software

The class is based on TurboCAD Designer 15 . This is an inexpensive CAD program which has all the features needed for basic model airplane design. Earlier versions of TurboCAD are usable, though the features and interfaces may be slightly different from what you see in the class. Later versions may have additional features not seen in version 15.

Sections

The first part of the class (CAD 101) was held in two sections. This was done because there were too many people for a good interactive session. We ended up with about 5-6 people per section. CAD 102 was the follow-on class. We had only one section of that because not everyone from CAD 101 went on to take CAD 102.

The main difference between Section 1 and Section 2 was the subject chosen. Since we had two groups, each was allowed to choose a subject aircraft. Section 1 chose the Klemm 35, section 2 chose the Aichi D4Y "Judy". The content of the two sections was more or less the same. The presentation was a bit smoother at times in section 2, since I learned a few lessons in Section 1 that were applied in section 2.

WebEx Recording Players

The class was held and recorded using WebEx, the excellent web based meeting tool by Cisco Systems. You should check the WebEx website for the latest info, but the links below work as of March 2010. The files are in ARF format. The player allows you to pause and skip any time you like.

Player for Windows/PC
Player for Mac (Intel)
Player for Mac (powerpc)

Class Content - CAD 101 (four sessions)

CAD 101 - Session 1

To download files, either Shift-left-click or Right-click then "Save As".

WebEx (ARF) Recording - CAD 101 Section 1 Session 1

WebEx (ARF) Recording - CAD 101 Section 2 Session 1

TurboCAD Interface

• Menus
• Toolbars
• Coordinate Entry
• Message Bar
• Coordinate Space
• Method - list vs. discovery

Importing and Tracing Raster Images

• Image Formats (JPG, BMP, etc.)
• Tools (Image editor) http://www.freeserifsoftware.com/software/photoplus/
• Insert -> Picture -> As Object
• Reference Lines

CAD 101 - Session 2

Justifying & Aligning the Raw Tracings

• Rotation & Scaling
• Cleaning up the drawing
• Grouping Objects

Scale & Size considerations

• Using reference lines and symmetry
• Scaling commands and procedures
• Model size considerations (Giant/peanut, accessories, Reynolds number)
• Removing unnecessary detail
• Power requirements
• Accessories (availability)
• Stock & sheet sizes

Bulkhead (former) and Rib/Spar placement

• Spacing formers & ribs
• Interior components
• Wing/fuse and wing/tail interface

Laying out Fuselage Formers

• Thickness (offset)
• Making reference polylines (bounding box)
• Cross section - splines
• Interpolation - lofting
• Fuse construction method (e.g. crutch)

CAD 101 - Session 3

Former Design; Lofting

• Dividing line segments
• Construction methods; crutch, box, stilts/jig
• Fuselage shape & curvature
• Offset command; sheeting
• Stringer size & placement

CAD 101 - Session 4

Misc. Commands

• Explode-Join (polylines, figures)

Wing Design

• Airfoil selection - using Profili2 - UIUC Airfoil Database - http://www.ae.uiuc.edu/m-selig/ads.html
• Incidence - wing & stab
• LE & Spar layout
• Rib design & layout
• Aileron & Flap placement
• Landing gear support

Printing & Plotting

Class Content - CAD 102 (four sessions)

Class Project Review

• Klemm & Judy
• Remaining work & assignments

Judy:

• Fuse - former thickness & draw on plans
• Wing layout, ribs
• Sub-spars, dihedral bracing
• Stab & fin framework
• Wing-fuse interface

Klemm:

• Fuse - finish formers
• Wing
  • finish layout & ribs
  • sub spars, dihedral bracing
  • landing gear support
• Stab & fin framework
• Wing-fuse interface

Wing Design (cont.)

• Trailing Edge Options
• Jigging & Washout

Material Selection

• Thickness of Formers & Ribs
• Cutouts (lightening)

Major Assembly

• Wing to Fuselage attachment
• Stab/Fin/Fuse interface

Printing & Plotting

• Plans layout
• Line Weight

CAM (Computer Aided Manufacturing)

• Laser cut parts
• Laying out parts for cutting
• CNC & future CAM

3D CAD (Vector)

• 3D Visualization & Orientation
• 3D Rotation, Right-hand rule

Also...

• Calculating the Center of Gravity using graphical methods
• Calculating cross sectional area and 3D volume for things like intake and exhaust ducts on jet powered aircraft (useful when designing ducts for EDF powered aircraft)

CAD 102 - Session 1

CAD 102 - Session 2

CAD 102 - Session 3

CAD 102 - Session 4

Further Info

There is a Google Group for exchanging information among class members. The original "live" participants are still on this group and many would be interested to hear from others who are learning CAD model airplane design.