Getting Started with DevFus Foam 2 – Hot Wire CNC Foam Fuselage

So you’ve made some wings with your Hot Wire CNC Foam Cutter and wondered if you can make fuselages as well   I’ve been on that journey to and now I can share my knowledge and experience.

I purchased DevFus Foam a few years ago and now there is a second release.   In my opinion its the best software for creating fuselages.  I did look for other options like Jedicut which you could make a fuselage with.  It will cut any shape from two profiles but you will need to lots of design work to create all the profiles.

I’ve made a Hawker Hurricane using the previous version of DevFus Foam and it was a challenge but turned out better than I imagined.  Here’s the build page

This article and the video series should help you to get started with DevFus Foam 2.  It’s not the easiest software to learn and the documentation is OK but more of a reference than a tutorial.  We are going to build a BAE Hawk jet with a 64mm EDF fan.  It’s also developed for the US Navy as the T45 Goshawk.

T45 Goshawk

Of course you can always buy one and they do look good and fly well.  But if you crash, it can be hard to repair if that’s possible.  Building your own if that happens means you can remake any broken parts.

How does DevFus Foam 2 work

We start off with a drawing of our intended model.  This can be a CAD drawing in DXF format or an image file, such as jpeg.  Several image formats are supported.

The image is imported, top and side views and then we calibrate it to our desired size.  Once we have the image DevFus Foam 2 creates outlines of the top and side views, but these usually need to be manipulated.

We are then asked for the size of foam to use and from that, the formers are generated.  Unless it’s a very simple design these will most likely need some work.  The first video is an overview and shows the basic operation.

DevFus Foam outlines

Once we have the formers we have some options for spars, lightening holes and sheeting.  DevFus Foam 2 introduced wing and canopy slots options.  On my Hawker Hurricane, I had to make a template for the wing slot and eyeball it on the fuselage and cut out the recess for the wing.  It was a bit tricky but worked out OK.


What do we need to get started?

DevFus Foam 2 isn’t free software but you can download the full version and use nearly every feature.  The only thing you won’t be able to do is to generate the g-code.  For that, you will need a license. Check .  In my opinion, the cost is well worth it and I haven’t found anything that’s come close.  Version 2 has some extra features such as wing and canopy slots.

Hot Wire CNC foam cutter – If you don’t have one yet then I have a series of articles and a free e-book.  This has all the details, plans and parts list.

Part 1

This video is an overview so you can see how the applications work without too much detail.

Part 2

This video starts at importing an image, our BAE Hawk and then covers creating the outlines of the fuselage.  The formers are generated and then we use some section cut images of our Hawk to get the jet intakes looking good.  The is probably where you will speed the bulk of your time. Quite a long video around 45 minutes

Part 3

In this video, I cover a quick tip to help align the formers with the image and then go one to create the wing and canopy slot.  I then show how to generate the g-code for one of the foam blocks.

Part 4

These are the foam parts of the fuselage made CNC foam cutter.

Dev Fus Foam 2 Hawk
devfus foam 2 hawk fuselage
DevFus Foam 2 fuselage parts

Part 5

Canopy and Wing/Tail slots

The Canopy and Wings/Tail slots were a little challenging and I did have an issue with the wing slot, which almost ruined 3 blocks.  The slot used the MH45 airfoil profile but came out too small.  After a lot of investigation, it turned out to be the kerf value (the amount of foam melted by the hot wire) causing the small size.  I did contact Stephano at DevCad and explained the issue and here’s a link to the post  

After some testing with scrap foam, I tried with a  kerf value of 0 and this fixed the issue.  It seems the inverse of what you would expect. 

Jet Intakes

The jet intake ducts were the next challenge.  To make these I created two templates using the DXF file you can export from DevFus Foam as a starting point.  After that, I used DraftSight to trace around the intakes of the reference image and copied these on the DXF file.  Almost there! 

Initially, I printed these out and pasted to some thin plywood and started cutting out by hand, which didn’t look great.  Why don’t I use my CNC router, that’s what it’s for making parts like this, doh.  So I imported the DXF into Fusion 360 and created the g-code.  The templates came out well and these were stuck to the former in front of the EDF.

Using a bow with a ni-chrome wire passing about 3 Amps was enough to allow me to follow the template manually and get the results below.  Quite pleased how they came out.


The wings can be made with free software such as JediCut and David the Swarfer G-code generator.  I have an article and a video on these

The companion program to DevFus Foam 2 is DevWing Foam  When I made the Goshawk I hadn’t upgraded to it But I have now and I’m very impressed compared to Profilli2 Pro which served me well. I have a full tutorial here

Part 6 Assembly

Here’s the video update on the assembly. Going together quite well with the wings covered in brown paper and PVA and will then be covered in white solar film. The fuselage is going to be covered with lightweight fibreglass cloth and Poly-C. I’ve decided to finish the Hawk as a US Navy T45 Goshawk

Getting close
t45 goshawk scratchbuilt
Nearly there just some decals to add
All done

Test Flight

Here’s the video of the finishing off and test flight that didn’t go so well. The problem was the jet tube was too small and I couldn’t get enough thrust for flight. Oh well, we live and learn. I converted here to a pusher prop but didn’t go too well either.

Where did I go wrong in the design?

The main problem was that I had the EDF in the wrong place with a too-small outtake nozzle size. I didn’t do enough research and fitted it in the widest part of the fuselage. Which was too far forward. After doing some research the EDF should be positioned around 4 times its fan diameter from the jet nozzle. I wish I read this before

Well, you live and learn as they say and the plane has now been scrapped. I will build another but this time following the recommended jet tube and nozzle size. This was my second build using DevFus Foam and despite it not flying I was pleased with the way it turned out from a visual perspective.

2 Responses

  1. David Ruiz

    Hola Keith, primero quería agradecerte, pues tus vídeos me han ayudado mucho a pesar de mi mal ingles, por eso te escribo en mi idioma nativo.
    La verdad esta es una petición algo peculiar, pues los software para cnc de corte con hilo son muy costosos y es por eso que tenemos que tomar las herramientas de código abierto que actualmente tenemos, ese es el caso del Jedicut, pues tu vídeo de como cortar las alas es muy bueno, pero seria excelente si pudieras hacer uno preparando y montando en Jedicut secciones de fuselaje, según ellos es posible hacerlo, ya lo he intentado pero las trayectorias son incoherentes. Gracias por tu ayuda.

    • Keith

      Hi David
      Thanks for kind words very much appreciated. Using Jedicut for fuselages is a lot of work because you need to create the profiles for each section cut. You would need to model the design in 3d with Fusion 360 and then slice the model and export the profiles as DXF so Jedicut can then create the g-code. I think this is why DevFus Foam is not free because it takes a lot of development. It is the best program for this. I’m very busy with other projects but maybe next year I can try and see if it is possible. What aircraft are you trying to model?

      Google translation

      Hola David
      Gracias por las amables palabras muy apreciadas. Usar Jedicut para fuselajes es mucho trabajo porque necesitas crear los perfiles para cada corte de sección. Debería modelar el diseño en 3D con Fusion 360 y luego cortar el modelo y exportar los perfiles como DXF para que Jedicut pueda crear el código g. Creo que esta es la razón por la cual DevFus Foam no es gratuito porque requiere mucho desarrollo. Es el mejor programa para esto. Estoy muy ocupado con otros proyectos, pero tal vez el próximo año pueda intentar ver si es posible. ¿Qué avión estás intentando modelar?


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