48″ Convair 240 for Electric RC
My whole love affair with CAD/CAM got started about somewhere around 2004 when I decided to start building balsa model airplanes again. I was very involved as a kid in building and flying radio control aircraft – mostly Antiques/Old Timers, which are pre WWII designs. But, with college and work and such, there was a good 15 years or so where I didn’t build or fly RC planes. In 2004 I got inspired to build planes again (really, I’m more of a builder than a flyer) and I also got some idea stuck in my head that I wanted to learn AutoCAD. Actually what I started with was a product called TurboCAD, but let’s not dwell on that…. What I found was that in the time I had not been making models, CNC laser cutting had become a viable and cost effective way of making kits. The idea that you could take a set of plans, trace them in a CAD program, email the file off and in three or four days these perfectly fitting balsa parts would show up was just too cool. Very quickly, the desire to build airplanes and the desire to learn some CAD basics merged. After a few people starting asking if they could buy the kits I was making for myself, I declared myself to be in the model airplane kit business, and purchased a 24″X48″ 70 Watt laser cutter from Emission Technologies. The Emission Tech laser cutter is a kit affair, which saves a considerable amount of money. The larger bed size is also perfect for doing kit production work, as you can load a bunch of wood sheets in it and let it rip. I had a fantastic time running my little kit company – Acme Aircraft Company – but made absolutely no money at it. Even in just the past 5 years, kit building has just gone to such a niche market – ready to fly planes that are more toy than anything else have really come to dominate the market. Oh well, I can certainly understand why those who primarily love to fly don’t want to spend hours on end toiling to build an airplane, and mass production has really brought the cost of the components way down, so at least there’s that. After running Acme, I went to work for AirCrafters, a homebuilt and experimental aircraft shop at the Watsonville airport. I basically showed up with a bunch of my balsa models in the trunk of my car and said “okay, I know you don’t make big airplanes out of balsa, but hey these things show I can make stuff.” I spent about three years at AirCrafters working on all manner of experimental aircraft – I learned a lot and was able to work on some really cool projects. Now that I’ve got my own company, I had to setup a proper office space, and so I decided to convert what was my model airplane studio – full of dust and tools and clutter – into a nice tidy design studio. One thing I found was that when you sit in your old model airplane shop, with a big laser cutter in the corner and a closet full of carefully sorted and weighed balsa, you start thinking, “You know what? I should uh…build a model airplane!” When I was active with Acme, I would often post on the Ezone forums, in the Scale Electric Planes section. I was browsing through the site a few weeks back, and noticed a posting about a Fun Build Contest for multi engine aircraft. I’ve always loved the propeller airliners of the late 40’s and early 50’s, particularly the Convair 240/340/440 series. To me, there’s just something so cool about these planes. The classic lines, the great color schemes of the era, I love it all. I collect documentation on pretty much any airplane that catches my eye, and so I already had a good stash of 3-view drawings, photos and other material on the Convair. So, I declared myself in the contest and started to peck away at the surface modeling in the off hours. I’m really thrilled to be designing a model again, and really looking forward to the build. It’s going to be a “stick and tissue” affair – think of a blown up Guillow’s model. I’ll be modeling it after this early 240 version, with the super cool retro Mohawk Airlines livery:
Okay, so that photo is black and white, but it really captures the lines of the plane. Here’s a color photo, you can see the color scheme has been updated a little bit in this one – I myself prefer the older version, but this will at least let you figure out which colors go where:
Here’s some screen shots of the surface modeling progress:
It’s a mix of T-Splines surfaces and standard Rhino NURBS surfaces. I’m hoping to get the surface model finished in the next two weeks or so so I can move on to the really fun part – making some balsa dust!