I realized I had never created a thread for this model although it has been built (by me and others).
I know there are/were other F-18 models out there but it really bugged me that so many (all?) of them only had a single engine. The dual engine setup is something distinctive about the F-18 -- also why not embrace launching with a 2x engine cluster (and heck why not make it a pair of 24mm engines). This also turned out to be a model that really lent itself to 3D printing. The center transition from the front BT-60 tube to the rear pair of BT-55 tubes can also incorporate the underwing intakes. It is funny how sometimes a part I want to design winds up taking so long but this part actually came together pretty quickly and works really well to bring together all the tubes as well as to mount / align wings and vertical stabilizers (although went through a few revisions).
As always my goal is to be as close to scale as I can be while working with standard body tubes and motors/engines (also while keeping weight as well as print time reasonable - i.e., using tubes and plywood where possible). I decided to do the F-18 Super Hornet since I liked the look of the intakes more. Below are a couple of pictures I found comparing the F-18 versions.
I get my scale via a few different processes. Sometimes I have to measure hundreds of dimensions from pictures of prototypes, other times I can bring scale drawings or photos into my design software as references images, I almost always use available measurements to check my work (and in rare cases there are enough measurements available that I can use that + pictures to design the model). Lastly, I sometimes use an existing scale 3D model as a prototype to help me design everything to scale. I still have to design all the parts from scratch (so they print optimally) and adapt to work with standard body tubes and to fit motors, but it helps to not have to constantly check scale for each little detail on each component. It also takes quite a while to find a good 3D design that is accurate enough to use for scale (or costs $$$) but I was able to do that here. Below is a mock-up that might help show how the original design can help guide the design of components for the 3D printed rocket.
Unlike many build threads, my process is a bunch of boring design time in various CAD-like design software, with some printing of prototypes, building full models, launching, and lots of revisions / iteration. No definitive - here is how I milled, sanded, and built-up this one-of-a-kind (one-off?) nosecone piece or something. 3D printing allowing iteration in the design is actually critical but the revisions come so fast and frequent that I am not sure it would be interested to see many of them. Here you can see how the various parts fit together to match the prototype.
Here is an early prototype of the main 3D printed components. Front tube is BT-60 and rear tubes are BT-55. The front tube is more cylindrical than the body on the real F-18 so the intakes wind up a little closer to the main body tube than on the real plane.
Test fitting wings and stabilizers. I made this about as big as I am able with my 2mm x 300mm x 200mm plywood that I use for almost all my models. I thought about (and mocked up) a two-part wing setup, but decided to do a single piece wing even though this requires that I let the grain in the plywood run horizontally through the wing. These are a little floppy before gluing to the body (the plywood is a light-ply with 3 layers but the direction of the grain in the outer two layers makes a big difference in strength). As I hoped, the wings are very strong once glued to the body so I think the decision to use a single piece of plywood was ultimately a good one.
Finally, here is the complete model next to a Big Bertha for size comparison.
I know there are/were other F-18 models out there but it really bugged me that so many (all?) of them only had a single engine. The dual engine setup is something distinctive about the F-18 -- also why not embrace launching with a 2x engine cluster (and heck why not make it a pair of 24mm engines). This also turned out to be a model that really lent itself to 3D printing. The center transition from the front BT-60 tube to the rear pair of BT-55 tubes can also incorporate the underwing intakes. It is funny how sometimes a part I want to design winds up taking so long but this part actually came together pretty quickly and works really well to bring together all the tubes as well as to mount / align wings and vertical stabilizers (although went through a few revisions).
As always my goal is to be as close to scale as I can be while working with standard body tubes and motors/engines (also while keeping weight as well as print time reasonable - i.e., using tubes and plywood where possible). I decided to do the F-18 Super Hornet since I liked the look of the intakes more. Below are a couple of pictures I found comparing the F-18 versions.
I get my scale via a few different processes. Sometimes I have to measure hundreds of dimensions from pictures of prototypes, other times I can bring scale drawings or photos into my design software as references images, I almost always use available measurements to check my work (and in rare cases there are enough measurements available that I can use that + pictures to design the model). Lastly, I sometimes use an existing scale 3D model as a prototype to help me design everything to scale. I still have to design all the parts from scratch (so they print optimally) and adapt to work with standard body tubes and to fit motors, but it helps to not have to constantly check scale for each little detail on each component. It also takes quite a while to find a good 3D design that is accurate enough to use for scale (or costs $$$) but I was able to do that here. Below is a mock-up that might help show how the original design can help guide the design of components for the 3D printed rocket.
Unlike many build threads, my process is a bunch of boring design time in various CAD-like design software, with some printing of prototypes, building full models, launching, and lots of revisions / iteration. No definitive - here is how I milled, sanded, and built-up this one-of-a-kind (one-off?) nosecone piece or something. 3D printing allowing iteration in the design is actually critical but the revisions come so fast and frequent that I am not sure it would be interested to see many of them. Here you can see how the various parts fit together to match the prototype.
Here is an early prototype of the main 3D printed components. Front tube is BT-60 and rear tubes are BT-55. The front tube is more cylindrical than the body on the real F-18 so the intakes wind up a little closer to the main body tube than on the real plane.
Test fitting wings and stabilizers. I made this about as big as I am able with my 2mm x 300mm x 200mm plywood that I use for almost all my models. I thought about (and mocked up) a two-part wing setup, but decided to do a single piece wing even though this requires that I let the grain in the plywood run horizontally through the wing. These are a little floppy before gluing to the body (the plywood is a light-ply with 3 layers but the direction of the grain in the outer two layers makes a big difference in strength). As I hoped, the wings are very strong once glued to the body so I think the decision to use a single piece of plywood was ultimately a good one.
Finally, here is the complete model next to a Big Bertha for size comparison.
