The A4/V2 rocket was developed by German scientists, including Werner Von Braun, during the 1930s and early 1940s. It was adapted for use as a weapon by the Nazis in WWII.
This model is hollow with 1.2mm thick walls, allowing for two extrusion widths of .6mm. The Slic3r settings for some of the parts use an extrusion width of .63 to ensure good bonding between inner and outer walls. I used the Slic3r engine within Repetier for this project.
The entire rocket is 22" tall and 2.75" in diameter. The mid-section and fin sections are each about 7.6" tall. When printed at 100% scale, the fins fit within a print diameter of 6.2", just fitting within the print volume of an Orion Delta. Quarter-turn bayonet fittings connect most of the parts. The groove in the bayonet fittings includes a locking bump that will help lock the parts when turned 90 degrees. Index bumps on the outside of the rocket help you know when the bayonet fittings are aligned for disassembly.
The nose cone base will bayonet-lock to the nose code. The nose cone base then slip-fits into the mid-section. The jet-vanes assembly friction-fits into the tail of the rocket.
This model is mostly for display purposes, but I have added some features that should make it possible to use it as a flyable model rocket. The nose tip has a compartment for adding weight to position the center of gravity properly for stability. The fin section has supports so a motor tube with centering rings can be held in place when the mid-section is attached. The mid-section has an internal shock cord lug. I have posted two versions of the mid-section, one with 3/16" launch lugs and one version without.
If sliced using the Slic3r settings I have provided, the 5% Archimedean chord fill-in provides reinforcing ribs in the fins to make them strong at a minimal weight penalty. I tried using the Cura slicer, but it does not have a fill-in pattern that is as good as Archimedean chords is for this purpose.
When you slice each part, you must place it in the orientation shown in the third photo to avoid the need for support material.
If you get the warning that the fin section is not manifold, you can ignore this and go ahead and slice it, at least with Slic3r.
When printed on the Orion Delta using MARS PLA, the fin section depends upon retraction to keep oozing and stringing to a minimum. But the frequent retractions can cause the hot-end to partially clog, resulting in under-extrusion on the cylindrical parts of the fin section while the hot-end is catching up.
I solved this by using the retraction setting that pushes .5mm extra filament after retract. The price you pay for this is some extra material at the ribs within the fins. This is mostly hidden anyway, but you may have to experiment with that value to prevent the ribs from showing through on the outside of the fins, especially if you have a different printer or use a different filament. If a few of the ribs poke through, and you are using PLA, it is usually easy enough to sand the outside of the fin down to make them smooth.
As Robertbl22 mentions in the comments, the nose and fin sections have some faceting on the surface. This seems to be a result of how I modeled those sections with FreeCAD. It was not a big deal to me, since the sanding, priming and painting I did to get rid of layer lines also removed a lot of the faceting.
If you build one of these to launch, please post photos and video of your rocket in action. I will seriously consider requests for modifications to the design that will help make it flyable.
Historical information and blueprints of the A4/V2 can be found here:
http://www.v2rocket.com/start/makeup/design.html
