Tuesday 31 October 2023
Wednesday 18 October 2023
FreeCAD, aside from generally being an excellent free and opensource CAD environment is ever developing and being extended. Over the last year or so a really interesting development has been the Rocket workbench. If you are new at the zoo, FreeCAD works with a workbench system where different workbenches contain lots of different tools grouped into themes. So for example if you want to convert a 3D part into a technical drawing there is a specific Techdraw workbench which, when you switch to it, has all the tools to lay out a technical drawing. Many workbenches are built in but you can also download and install extra workbenches of which the Rocket workbench is a good example. I’d love to see more rocketry people using FreeCAD and so this post is aiming to show why FreeCAD, as well as Openrocket, might be well worth learning!
Openrocket and FreeCAD have lots of active development happening and it just happens that an amazing contributor, Dave Carter, AKA DavesRocketShop, is contributing development to both these excellent opensource pieces of software. Further than that Dave realises how powerful interaction between Openrocket and FreeCAD might be and is working to make both these packages work together usefully.
As a starter example (but frankly enough of a reason for many rocketry types to learn some basics of both these packages) is the built in parts database. In Openrocket if you are designing a rocket from scratch you might chose to incorporate an off the shelf nosecone for example. Clicking the Nosecone icon in openrocket the component database will either launch automatically, or you can launch it from the regular nosecone dialogue window by clicking the “parts library” button in the upper right hand corner. Either way you’ll see a well maintained and curated list of commercially available nosecones from a range of manufacturers.
OK, Over to FreeCAD. Say we now can’t find that commercial part to buy in our local rocket shop we might think about having to draw it in CAD and perhaps 3D print it. Well, the exact same database is available in the Rocket Workbench in FreeCAD. Clicking the nosecone tool icon should launch a nosecone parameter dialogue in the combo view window on the left of the screen. Scrolling down you can click “Lookup” to launch the exact same database of components as you just launched in openrocket. You can scroll to the same nosecone and select it and it will appear as an object in the live preview and also as an object in the combo view. If you wanted to simply 3D print this you can select the object in the combo view window and then click “File-Export” to export the nosecone ready for printing. You can pretty much do this without learning any more about FreeCAD and Openrocket if you wanted too, but, if we learn a few more skills, we can do some other really simple yet useful rocketry tasks.
Another simple example perhaps of use is imagining we want to build an upscale version of a rocket with a scaled up nosecone. If we select a nosecone from the database in FreeCAD we can then jump over to the Draft Workbench. With the nosecone selected we can now click the “Scale” tool icon. As a tip to help you find tools, if you hover over any icon in FreeCAD it will say the name and a small description of the tool and I describe the tools with the names these rollover descriptions use. In the scale dialogue click the “enter point” button and in the next dialogue make sure that both the “Uniform Scaling” and the “Create Clone” buttons are selected. Then change any one of the X Y or Z axis scale amounts to the scale you require, so for example if you want to double the size of the nosecone change one value to “2”. The other values should change automatically and then when you click OK an upscaled (or downscaled) version of your nosecone will appear as an object.
Finally, for this example, if you know a little about using FreeCAD you can easily add geometry to parts you create on the rocket workbench. In the image I’ve simply brought a cloned nosecone part into the Part Design workbench and then added some features to make an attachment point for a recovery system. If you are interested in developing your FreeCAD skills my free to download tutorial book FreeCAD for Makers is available from the Raspberry Pi Press here.
This is only the tip of the iceberg in terms of what what FreeCAD and Openrocket are capable of. The Rocket workbench is amazing in terms of what it can automatically generate parts wise. Nosecones, transitions, tubes rings, rail buttons, rail guides and more; there is a really impressive fin can generator as well as some pretty high end fin flutter analysis tools. The real beauty is that you can simply transfer dimensions and data over from a design you have worked on in Openrocket. Having rebuilt it quickly in FreeCAD there are so many options available, as an example I can simply select a centring ring in the FreeCAD design and take that part to the Path workbench and create toolpaths to then cut the rings on my CNC router. I can export all manner of files for parts for laser cutting or other processes. It’s a really good tool to learn some skills on if you are a rocket fanatic!
Monday 2 October 2023
So this could win the award for the most overdue blogpost ever. Back in summer I attended Liverpool Makefest as a maker and showed off lots of flying stuff under the title "Concretedogs Flight Lab", which coincidentally is also the title of book of projects I've been not finishing for a long time! One of the activities I showed and told at Makefest was my DIY Hot Air Balloons.I originally wrote about these ideas back in Hackspace Magazine Issue 61 where I talk about their construction. As most councils have quite rightly banned the use of fire filled disposable balloons the approach here is to heat the balloons to perform shorter hop like flights and, when indoors, use a light kite line as a tether.
Monday 4 September 2023
Sunday 20 August 2023
Monday 24 July 2023
I'm really lucky that over the years I've got to visit and work out of loads of makerspaces, hackerspaces, fablabs and others. Mostly in the UK but a few notable overseas ones also. I can't say that this one is overseas, well apart from you need to get a ferry to visit Makerspace Arran on the fantastic and beautiful Isle of Arran.
In fact, if memory serves this is only my second ever Scottish makerspace, my first being the sadly missed Maklab in Glasgow which I was lucky to visit and hot desk from a few times over the years. I was really interested to have a quick look at Makerspace Arran as it's in a similarly remote and rural position as some of the Ffiws makerspaces I've been involved with here in North Wales. It was only a flying visit but it was lovely to see a few of the projects I'd spotted on Makerspace Arran's social media in the flesh. The space is actually on two levels with the ground floor being a shop. The location of the shop is right at the start of a very popular walking trail up Goat Fell which is the highest summit on the Isle of Arran. Also at the foot of the path around the makerspace are a garden centre, a pub (which does great chips) a microbrewery and a leather workers workshop and shop. There's a stack of parking and a lot of tourist footfall in the area.
The shop sells stuff that has either been made in house or has been made on the island and has a great range of gift items that are really nicely curated and relevant to the location. There are no "kiss me quick hats" or other generic stuff, everything is made here, and has links to Arran. It's really impressive. There's lots of stock of tee shirts commemorating your walk up Goat Fell and small lasercut medals as a reminder of your successful ascent. They've researched some of the traditional historical games that would have been played on the island in times gone by and reproduced them using the laser cutter. They are also up for helping out other producers and makers.
There were some lovely cast epoxy broaches and necklaces where the epoxy has been cast into the shape of Arran itself and Mark told me about how they had used the 3D printers to help create objects to then create silicon moulds from to help the maker increase production and accuracy. One fantastic project is the lasercut Liberator 1 LB30A kit which has a sad connection to Arran in that one crashed into Mullach Buidhe in 1941. The lasercut kit is created in 1.5mm plywood and has interestingly used as a source an old book of air plane silhouettes which was created in wartime as a guide for civilians to identify aircraft.
They aren't all about the profit though, the small makerspace located above the shop is beginning to look at running workshops for anyone to book into. There's currently an exploration to see if there is enough interest in workshops around scale modelling using kits. I did offer to run a FreeCAD workshop up in the space whilst we were visiting but sadly, due to some makerspace members being off the island that week it wasn't to be! Ah well maybe next time!
Tuesday 9 May 2023