Design with CAD

 

Computer Aided Design programs have revolutionized the field of creating construction plans. From cars to architectural projects to full scale aircraft production, the ability to design with CAD makes the job fun, easy and quick when compared to hand drafted plans.

Initial pencil sketch of the Chickadee

Initial pencil sketch of the Chickadee

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.


You need to consider a few items before starting on a path for using CAD on your next 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.

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.

I recommend that you practice your initial CAD 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.

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.

CAD sketch of the Chickadee

CAD sketch of the Chickadee

I have tried several CAD programs 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 am using now.

CAD plan of the Yard Ace fuselage

CAD plan of the Yard Ace fuselage

It will be a challenge the first time you design with CAD. Remember that CAD is simply 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.

For a first model airplane CAD project I recommend that you prepare a set of plans for a “dummy airplane.” Just make up an airplane and draw it out.

The idea is we are focusing on how to use the various tools available in a CAD program without worrying about the exact placement or size of a 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.

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.

Hand drawn plans for the Yankee Mike, my first RC plane design

Hand drawn plans for the Yankee Mike, my first RC plane design

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.

TurboCAD drawings of ParkZone radio control electronics

TurboCAD drawings of ParkZone radio control electronics

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.

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 program operates. But once you prepare a letter in Word there is no going back to the manual typewriter.

To help with your practical understanding of TurboCAD, consider purchasing my two CD training program for TurboCAD. These narrated 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. Note that you do not have to own TurboCAD to view these videos as the files play with Windows Media Player.

Author: Gordon McKay