\[ \]
\[ \]
\[ \]
Issue No 67, 27 October 2025
By: Anthony O. Ives
Helicopters parts are usually more complex to make than airplane parts, when I started of building model airplanes I built them from balsa wood, spruce wood and plywood using hand tools. Its generally possibly to make a lot of things from on a fairly modest budget using wood but not really helicopters parts, which is the one thing which make helicopters more awkard for me however, it was the only thing I really liked about airplanes. I did a learn a lot about how to go about building aircraft parts from building airplanes so I cannot say it was a completely wasted experience and it helped me develop some woodworking skills. However, for helicopters particularly RC helicopters they are usually made from plastic or more correctly polymers, larger full scale manned helicopter were traditonally made from metal machined components. I really just started researching how to make helicopter parts myself so far I have thought about using 3D printing, CNC machining as well as various composite processes [1].
Out of all the ways I going research 3D printing is the one I know the least about and I would not say I do not know a lot about any of the other methods. However, from what I know about it 3D printing seems to be very easy to learn how to use, you can even use it to replicate parts if you have a 3D scanner. Generally you will a computer CAD model [2] and a 3D printer, once you have these you can simply print the model in 3D as you would print out a document. Your 3D printed component will be made from a polymer material however, I recently just found out there are 3D printers that use a range of materials including things like chocolate! The 3D printer usually builds you component in layers from the bottom to the top. In some cases the component may need a bit of finishing, e.g. sanding smooth any rough edges as well painted, etc.
My big apprehension is how a 3D printed part behaves structurally, so I would be more inclined to not use 3D printed parts for things that are likely to be exposed to high stresses such as main rotor blades. I might consider using 3D printed swashplate on smallish RC helicopter as it would think it is not exposed to too much stress. I would probably use 3D printer to create RC helicopter Tail rotor blades, control paddles (for flybar RC helicopters) and anything that is purely aesthetic with no real structural function. The main blades holders I might be tempted to use a 3D printer to make even though I think they would be high stress components but that is because two of the RC helicopters that I own which includes my largest RC helicopter uses plastic components. See pictures below of typical components that could be possibly made using a 3D printer.
For things like tail rotor blades, flybar paddles (on smallish RC helicopters) I would have no problem using a 3D printer to make them and maybe even swashplates, tail rotor holders, thought a swashplate would possibly need a bearing and other metal components to completely function. To use a 3D printer to create other components such main rotor blades holders I would like such reassurance that a 3D printed component could hold out to the stresses imposed. As the helicopter I was building becomes larger I would use CNC machined components or composite components for more structural integrity. 3D printing of course can be a very useful way to make mould patterns for composite parts, I will discuss this bit more later in the article. A typical 3D printer at the time of writing costs around $200.00 (or £149.99), for a typical example that I researched see the link below:
https://www.amazon.co.uk/WEEFUN-TINA2-3D-Printer-series/dp/B0DF1M4Z6N
If you have 3D scanner you can easy 3D print duplicate parts using an existing part or you could create a mould pattern similar to what is done in sand casting. The other way to do it is to create a 3D CAD model using CAD software [2]. If I wanted to use CAD to create a model for 3D printing I would probably use FreeCAD [3]
The FreeCAD manual [4] describes in detail how to prepare your finished CAD model for 3D printing. Obvious things about CAD model need to be checked before exporting your model for 3D printing such as that the CAD model is solid. 3D printers cannot take CAD files directly they have to be converted a machine language call G-Code which is specific to each 3D printer. The G-Code is generated by a program called a slicer which slices your CAD model into various different layers which if you remember how the 3D printer works it build ups your 3D printed part in layers. The 3D printing preparation process for FreeCAD is explained in more detail in the FreeCAD manual, in a section called 'Preparing models for 3D printing' [5], but you may need to look further if you want to delve into G-Code, etc as 3D printing is vast subject which I am only starting to learn about.
CNC machining can create parts similar to 3D printed parts but using a different process. In CNC machining parts are machined out of a block of material. Typical materials used in CNC machining are wood or aluminium. I have gave some examples of helicopters parts made using CNC machining in the pictures below:
A hobbyist or small project CNC machine can be purchased online for $945 (or £699) at the tíme of writing. However,these seem to be mainly for engraving in wood or soft aluminum how suitable they are for making RC helicopter parts I am not sure. Professional CNC machines are still revelantly expensive, but you make use of CNC service provided by a professional machinist. I have read some Popular Woodworking articles [6] on CNC machining mainly for woodworking but the same principles apply for other materials such as aluminium [7].See the link below for typical CNC machine that can purchased online for hobbyist.
https://www.amazon.co.uk/Genmitsu-3030-PROVer-Accuracy-Precision-Engraving/dp/B0CH9KCQ6C
Like 3D printing a CNC machine requires a CAD model in order to produce the part, you could probably also produce replicate parts using a 3D scanner as can be done 3D printed, thought I am not entirely sure. The process of converting CAD files to files needed for CNC machining probably varies, so best to find out the process before purchasing the CNC machine. If you are using a CNC service, you may only have to provide the CAD model file and machinist can convert the files or they might want a specific file type, etc.
As with 3D printing, CNC machining can also be used to create mold patterns rather than just creating parts directly. Mold patterns are needed for most processes which are used to make ccomposite parts. The next section will discuss the processes for making composite parts.
Composites were introduced briefly in a previous article [8] . In summary a composite consists of two different components, a reinforcement and a matrix. The reinforcement is a fibre material which gives the composite strength whilst the matrix is a polymer type material which gives the composite stiffness. Wood is actually considered a naturally occurring composite.
Composite parts can be made using a range from very simple home made methods to highly sophisticated industrial processes. Some of the simplest methods use glass fibre lay ups which essentially just paint on the epoxy resin. The lay up is usually done on a mold pattern. Other more advanced techniques use autoclaves, which are essentially pressured ovens which can be used to create highly accurate composite parts. Most composite making techniques require a mold pattern. Obviously mold patterns can be made using 3D printing or CNC techniques as I mentioned earlier. The material choice is important depending on the process that you are using, certain temperatures and pressures will not be suitable for some materials. For more on composite making processes visit https://www.easycomposites.co.uk, [9] or https://www.compositesworld.com, [10]
Composites are ideal for making components that require high strength such as rotor blades although you can use them to make other components such as canopies which do not necessarily require high strength.
Most of the techniques described in this article can apply to kit helicopters as well as RC helicopters just obviously the components have to be to higher specifications but all components should be made carefully as even small RC Helicopter can be very dangerous if their components are poor quality. Hopefully in a future article I will dicuss kit helicopters a bit more.
Please leave a comment on my facebook page or via email and let me know if you found this blog article useful and if you would like to see more on this topic. Most of my blog articles are on:
Mathematics
Helicopters
VTOL UAVs (RC Helicopters)
Sailboat Design and Boatbuilding
If there is one or more of these topics that you are specifically interested in please also let me know in your comments this will help me to write blog articles that are more helpful.
References:
[1] https://www.eiteog.com/EiteogBLOG/No59EiteogBlogStructure.html
[2] https://www.eiteog.com/EiteogBLOG/No60EiteogBlogFreeCAD.html
[4] https://wiki.freecad.org/Manual:Introduction
[5] https://wiki.freecad.org/Manual:Preparing_models_for_3D_printing
[6] https://www.popularwoodworking.com/techniques/mill-brass-aluminum-with-a-cnc-router
[8] https://www.eiteog.com/EiteogBLOG/No59EiteogBlogStructure.html
[9] https://www.easycomposites.co.uk
[10] https://www.compositesworld.com/
Disclaimer: Eiteog makes every effort to provide information which is as accurate as possible. Eiteog will not be responsible for any liability, loss or risk incurred as a result of the use and application of information on its website or in its products. None of the information on Eiteog's website or in its products supersedes any information contained in documents or procedures issued by relevant aviation authorities, manufacturers, flight schools or the operators of aircraft, UAVs.
For any inquiries contact: [email protected] copyright © Eiteog 2023