ready to fly

Decoration

I decided my airplane needed some identifying insignia, so I set about figuring out how to do that.



The tail surfaces are flat and present no difficulty, but the fuselage and wing surfaces have curves that resist direct drawing techniques.

The maltese cross image was projected onto the slightly curved sides with a technique demonstrated in a video tutorial by Aidan Chopra, author of "SketchUp for Dummies".

For the crosses on the wings, I tried a plug-in tool that allows drawing on curved surfaces, but I couldn't achieve the kind of precision needed to complete the design successfully. In the end, I used the same technique that allowed me to cut the hole for the cockpit.

A form with the desired profile is pushed through the surfaces, the two objects are merged, and new edges and surfaces are created. Once an area is enclosed with a continuous perimeter, materials and images can be projected or painted onto it without leaking onto the contiguous surfaces.

I've also scaled back the cowling a bit to give the plane a profile a bit more in line with photos I've seen of it. I'm planning on tweaking a few more details, laying on some color, and hope to wrap up this project in a week or so.

All the parts together

I'd like to do a bit more with this Fokker d.VIII, but my old Dell computer is balking at the prospect. In order to display the shadows in this image I had to turn off hardware acceleration, so the process really slows to a painful crawl. I have learned quite a bit from doing this model, however, so I think I can put this one in the success column too. I can go back to doing simpler models for a while as there is still a lot of the basics I need to learn.

around and around

I'm working on a new SketchUp model of a WWI plane. The 110 hp engine in it was an Oberursel Ur.II, a German product copied from a French design. I was vaguely aware that in such rotary engines, much of the machinery went around along with the prop. It wasn't until I began looking at CAD representations that I began to understand why the rotary was considered a good idea at the time, or what made them work. Two CAD depictions in particular make the functioning of rotary engines a lot easier to understand.

The cut-away depiction below is from the marvelous Vintage Aviator site. If you look closely you will see the key feature of the engine, which is that there are two axes of rotation.



How the machinery is linked by the two axes is illustrated with great simplicity by an illustration at the Animated Engines site. Once there, click on the "Gnome Rotary" link to view the animation. Under the "About" link, you will also find an excellent explanation of how the engine animations are produced.