Designing an RC Model Airplane with CAD
Tips and techniques for designing with CAD programs
Computer Aided Design, or CAD programs, has revolutionized the field of design. From cars to architectural plans to full scale aircraft production, the ability to design something with CAD makes the job fun, easy and quick. Designing radio control model airplanes with a CAD program is no exception to this process. You will find that once you make the jump to using a CAD program for your design efforts, there is no going back to paper and pencil.
3D CAD drawing of a park model airplane nose
You need to consider a few items before starting on a path for using CAD on your next radio control design project. Clearly, you will require a computer with at least Windows XP and enough RAM and disc memory to load whatever CAD program you will use. Just about any computer purchased within the past two to three years will have enough graphical and computational horsepower to perform typical CAD tasks.
Develop 2D CAD skills
I will make the assumption at this stage that you will be developing your two dimensional (i.e. line drawings) CAD skills. 3D CAD graphics require a higher level of computer performance and training, which will not be a part of this discussion.
CAD programs can apply colors to different airplane parts
I recommend that you practice your initial CAD designing efforts on a large computer screen. While one can certainly operate a CAD program on a laptop, the smaller screen may hinder your learning progress. I would recommend accessing a larger screen to have a better visualization of what could turn out to be a detailed model plan.
CAD is used for accurate laser cut balsa ribs on the Electro Aviator
Once you have the hardware issues settled, the next step is to select a CAD program. There are numerous quality CAD programs available for designing an RC plane. I have tried several, to include AutoCAD LT, QuickCAD and Drawing Board. I have been using TurboCAD since 2000, and I am completely satisfied with this product. TurboCAD is a mature, affordable and intuitive CAD program aimed at the home user. My initial plans, such as for the Electro Aviator, where prepared with TurboCAD Ver 8. I have since upgraded to Ver 16, which I used to draw the Robin plans.
Practice CAD model plane design skills with a notional aircraft
It will be a challenge the first time you design with CAD. Remember, CAD is just a precise method of putting lines and curves down for a final drawing. The more you use a CAD program, the quicker you will be able to think ahead on techniques required to draw whatever object you are working on.
Design a notional airplane
For a first model airplane CAD project, I highly recommend that you prepare a set of plans for a “dummy airplane.” Just make up an airplane layout and design it. The idea is we are focusing on how to use the various tools available in a CAD program without worrying about the exact placement of wing or tail surfaces. You will be using these program drawing tools - lines, curves, bisecting, snap, trim - with every project. By starting with a notional airplane subject, we do not have to worry about correct dimensions for a true flying model. All that will come later.
Chickadee CAD model airplane plan
Once you get proficient with drawing the basics of an RC model airplane plan, the next step is learning how to draw specific objects. One of the really cool features of a program like TurboCAD is that every object is drawn “full size” within the program. For example, a wing may be 20 inches in span. You can zoom in or out to make the image on your computer screen appear larger or smaller, but TurboCAD “knows” the wing is always 20 inches in span.
Learn TurboCAD with this video CD training
CAD keeps true dimensions
This invaluable feature allows you to draw anything that will be part of the airplane and retain its real dimensions. You can draw servos, receivers, and engines to their full size. It is a simple matter, for example, to see how your electric motor will fit into the airplane nose section you are creating. Once these components are drawn, you can save and use them for future projects. It really is amazing to “fit” modules like a servo or a motor onto a design and make any necessary changes before you start cutting wood.
Designing with CAD makes model aircraft prototype updates very easy. You will eventually make a finished outline of your design, and build and fly a prototype. As part of the flight test process, you will make changes to the original layout. You may wish to widen the fuselage a bit, extend the wingspan, or change the shape of a tail surface. This is where CAD really comes to the rescue. You can make these changes instantly. It is a simple matter to take the original design, use only half of a view, and draw your update on the other side. Once complete, erase the older version, and using the mirror command, quickly make the new model’s shape complete. The Finch is a good example of a free CAD plan you can download here.
Example of using TurboCAD to design an RC model airplane - buy the complete two CD set here
Using a program like TurboCAD is very much like progressing from a manual typewriter to a computer word processing program. There is a learning process to grasp how the computer operates. But once you prepare a letter in Word, there is no going back to the manual typewriter. As you gain experience with various kits and plans, you will appreciate the linkage of a well designed CAD plan with a laser cut kit, such as with the Pietenpol Air Camper homebuilt aircraft.
To help with your practical understanding of TurboCAD, please consider purchasing my two CD training for TurboCAD. These computer screen videos take you from a clean sheet of paper to a finished RC model airplane plan. The videos are will save you months of work figuring out TurboCAD on your own. Please note that you do not have to own TurboCAD to view these videos, as the files play with Windows Media Player.