If you want to print this model yourself, your printer need a minimum build volume of 163x163x196mm

In-depth guide on how to print and assemble this model: “How to Print & Assemble The R4PTCR-M1”.

Scale: 1:8
Overall dimensions:

• Nozzle Diameter (bottom): 162.5mm
• Height (top of Engine Mount to bottom of Nozzle): 395mm

Manufacturing lead time: 1 week
Total number of 3D printed parts: 35

This model was designed using publicly available material from the internet including CAD models, videos and pictures. See list below for more details:

Engine
The Engine was designed based on the existing Rocket Engine model by Charles Lesher (see LINK). He has done a fantastic job modelling the engine so I used his model (with his permission) as reference and added my personal touches. I re-designed almost every part of the original model so they can be fitted together without having to use super glue. Instead, all parts are held together by magnets. This allows my model to be fully stripped down and rebuilt as many time as required. Only two small parts of the model need gluing together (the LOX Valve and LOX Distribution Valve)

Crossed Arms Man
I came across the Crossed Arms Man model, designed by mcramblet on GrabCAD (see LINK) and I think it would be a really nice touch to print this model at the right scale and put it next to the rocket engine. This would definitely help people (including myself) to understand the true scale of the real Raptor engine in reality (as many of us don’t have the luxury to see it with our own eyes)

Firstly, Charles has done a fantastic job modelling the rocket engine – there’s no doubt about it. However, I found a couple of issues with his CAD model when I started to look deeper into the design (some geometries overlaps each other, some parts are fitted together but there’s no clearance between them, some parts are supposed to be symmetrical (I believe) but aren’t, etc.) so I decided to give his model a complete makeover.

1. I scaled the design up to 1/8 instead of 1/11 – just because I want to make some small details easier to print on an FDM printer and also 1/8 scale is much more popular than 1/11
2. I modified every part of the original model so they can be printed either support-free or with very minimum support, hence, better surface finish.
3. I merged some parts together so the pieces are located more accurately (instead of gluing them into place by hand). Specifically, I merged the ‘Mounting Plate’ with the 2 ‘Gimbal Upper’ and the ‘Control Strut Collar’ with the 2 ‘Gimbal Lower’
4. I redesigned the LOX Turbopump from scratch to make it easier to print and also looks better
5. I modified how all the main components are fitted together – you can now fit magnets into them (the magnet I use is 5mm diameter x 3mm thick) and they’ll stick to each other without having to use glue. This makes the model really fun to assemble! (and disassemble)
6. I redesigned all the small pipes from scratch to make them look more realistic – as you know, all complex pipes are typically manufactured from straight pipes, they get bent at several locations and welded with other pieces (e.g. brackets, clips, fittings, etc.) to achieve the final desired shape. Therefore, when you look at a real pipe on any engine, it normally have several straight sections and several bends. I think Charles’s original design of the pipes are a little bit too ‘curvy’. In addition, because the pipes are so ‘curvy’, it’s very difficult to orientate them to get an optimum print on an FDM printer. That’s why I decided to re-designed them all – you can see on the new pipes that I designed, each one has at least a straight section to help alignment with the print bed.
7. I added magnets to both ends of every pipe (both small and large), so you can attach/detach them to/from the engine core.
8. I removed all the arrows from Charles’s pipes, just because they are not every visible, and also, because the new pipes are detachable, what you can do is simply print them in different colours to show the flow of LOX and CH4 around the core
9. I removed some of the small bolts from Charles’s design (e.g. the ones on the flange at the ends of each pipe) because I think they are too small to be printed on an FDM printer.