Case Study - Flying Quadcopter: Attack of the Drones

 

ImageThis month our Case Study focuses on another project created by the multi-talented Michael Castor who built the Pi-Pad we showcased last month. In this article we focus on a Flying Quadcopter that he built using Aspire and his home built CNC. He starts by explaining how the need for this particular project came about.

Drones are an addiction. You start with something small to learn on, then move on to something bigger like a 3D Robotics drone. You build it, you fly it, and it’s awesome. Then you crash it and turn your $600 quadcopter into a an unrecognizable pile of parts. At least that’s what happened to me...

Having crashed the Drone on the test flight Michael took the wreckage home and examined damage. Having turned the airframe into a tangled spaghetti type mess of fibreglass and aluminium he was suprised at the fact the majority of the electronic survived. Still with a fully functional APM (autopilot unit) with a nice crack in the case a perfectly working GoPro with another shattered case and two completely broken motors, Michael decided to dust off the salvaged parts and try again. In the words of Michael, "What goes up must come down and what comes down can sometimes go back up". So after a great test flight soaring above rooftops to a very turbulent landing, it was back to the drawing board for Michael. His deadline, the Maker Faire in New York 2013.

ImageI had never been a huge fan of the 3D Robotics frame. Yes it was rigid and light but it was rather big. It was a pain to store and difficult to transport in my car or anywhere else. My goal for this project was to make a new drone frame that was light, robust, easily transportable, and about the same dimensions as the my previous drone so I wouldn't have to re-tune the flight controller.

After spending some time online looking at folding frame designs I decided that a "folding 'H'" would work best for what I was trying to accomplish and would give me plenty of room to mount a GoPro or similar action camera. I needed a strong, lightweight material for the arms so I went to the local home improvement store to see if I could get any ideas. I found inspiration in the bathroom section and came back with two 24" long 5/8" aluminum towel bars.

Using the dimensions from these arms I used Aspire to draw up my own frame. I decided to make the top and bottom plates interchangeable for simplicity. I somehow managed to fit these plates, motor mounts, and camera riser onto 1 – 24″ x 12″ sheet of 0.063″ G10 fiberglass. I considered 3/4″ square aluminum tubing for the arms but I was concerned about weight – especially if this thing was going to carry FPV gear. 

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After I was happy with the design I machined the frame from black 1/16" G10 fiberglass using a 1/16 carbide grout removal bit (Dremel #569). I cut the arms to 7" each and machined a jig to keep them in place from 1/2" MDF. The arms themselves were machined using a 1/8" straight bit which worked wonderfully. I sanded the fiberglass parts using 220 grit sandpaper under running water to remove any possible splinters.

I originally considered using nylon screws to keep the frame together but after seeing the prices on McMaster Carr I opted for traditional M3 screws and lock nuts. I also priced standoffs but wow – those things are pricey! I started thinking about alternatives and went down to the workbench. I had some small poly tubing so cut off several pieces to try to get a consistent length. That didn’t work. Then I thought – “Hey, I have a 3D printer – I’ll CAD some up and print them!” So I did. And they worked! I CADed up some that were 5/8" tall and printed them on my 3D printer.

The frame is held together using M3 screws and locknuts, and pins hold the arms in place during flight. When not in use, the drone folds up small enough to put inside your carry-on suitcase making it perfect for travel.

 

There are plenty of features and gadgets that enable the users to make their work flow more efficiently for any project, so we asked Michael if there were any other stand out features that helped him with his project.

Yes of course, I used mirroring quite a bit for this project, as well as the rotate feature to individually rotate the arms to make sure everything would fold up nicely.

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So what tips does Michael have for other makers out there?

Spend time watching Vectric's tutorials - they are very well done and will speed up your workflow and help you get the most out of the software and your machine. Also, when trying to do multi-sided machining, take your time, save everything as a separate file, and clearly label and organize all your cut files. Finally, take extra time to document your projects while you are making them. This will enable you to not only share your project with the world but also to have a record incase you need to repeat the project or repair it down the road!

And what of the future?

I have too many projects and not enough time! I'm planning on making a PiPad Mini based on a 7" screen, a small (sub 12") hex-copter, and a PID controlled coffee maker. I also have a 1968 Ducati Monza that I'm gradually turning into a cafe racer. Vectric software will play a key role in making each project happen.

To download the design files for this project please visit:

www.mkcastor.com

 

 


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