Even without plans, building your next dream model airplane is possible!
By Andy Kunz PHOTOGRAPHY: ANDY KUNZ & MICHAEL RAMSEY T 34
he summer of 2011 in our area was in a drought. I had not mowed my lawn since early May, and every- thing was brown. Some trees had already started turning as if it were Au- tumn. It made for great flying all summer, as we never missed a weekend due to rain. A week or so before Labor Day we had some rain, just enough to start reviving the grass enough to mow again. Then came the big news—remnants of Hurricane Irene would be visiting us for the Labor Day weekend. Three days of rain, no work and no flying. What to do? What to do? I know, I’ll build a model!
I had long wanted to build a stand-off scale micro model of the Fairchild A-10 Warthog. I had started gathering bits for it—two E-flite MiG-15 fans, some Spektrum ultra micro servos, Castle 5A ESCs—but didn’t have plans. I did find some good 3- views on the Internet, so I built directly from them. What I’m going to describe in this ar- ticle is how it was accomplished, and how
you can do the same for a model that you’ve wanted but don’t have plans for. We will look at techniques and some shortcuts that are appropriate for a one-off model, especial- ly a smaller one. Basically, we will scale the 3-views to the right size, sketch in some rough plans, and build.
There are many Internet sites with 3- views. I find them simply by searching for the plane I want, downloading several dif- ferent versions until I find one with the largest pixel count and detail. Get in the habit of collecting 3-views this way and you’ll never lack for a building project. I usually scale micro Pattern planes to about 100 square inches of wing area. For others I use a comparable Horizon Hobby UMX model as a reference. Horizon doesn’t have any twin EDFs though, so I looked up the MiG-15 specs and found that it had about 53 square inches. As a twin, I would want to have more area to carry the weight of the extra fan and battery. I decided to tar- get 90 square inches. The added weight
would mean it would need to fly fast too. It’s a jet—speed is a good thing!
I imported the 3-view images into Adobe Illustrator and scaled the wings to the area I wanted. The software doesn’t have to be as sophisticated as Illustrator, but it does have to have a scaling feature. You need to do a little math here to convert the image from the imported size to the desired size. For in- stance, if you calculate the wing area as im- ported and it comes out to 50 square inches at 20-inch span, and you want 90 square inches, you need to find the square root of the ratio 90/50 and scale the dimensions by that number. If you have a spreadsheet pro- gram this can be very easily performed. The 3-views I selected for my source were in three files, and scaled differently. After I got the top view scaled, I imported the side view and then had to manually scale it and align it so that the fuselage length was the same in both views. I got it to within 1⁄16 inch which was close enough and, because the side view was larger, it would also adjust au-
JANUARY 2013
Pro
Pad
Without Building
Plans Plans
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