The planetary burn rate

In economics the burn rate is synonymous for how fast a company will use up its shareholder capital. Once exhausted, the company will either have to make a profit, find additional capital, or default.

offsetting my carbon footprint

Living and working in Boston makes me fly a lot. I fly back home on a regular basis to visit family and friends. International conferences make me travel by air as well. This year I decided to offset all my flights to reduce my carbon footprint from flying and go CO2 neutral on this front.

Although offsetting my carbon footprint is not substitute for not accruing one in the first place this is the best what I can do as of now, given my work situation. I hope my actions might inspire other people to start thinking about their carbon footprint and how to offset it.

I offset my footprint using a Belgian company called co2logic, but other companies offer similar services.

Quadcopter parts are milled!

Thanks to Ryan Nolin at Skyview Images I could mill my quadcopter parts. Below a snapshot of the parts. I’m anxiously awaiting the parts so I can finish my build.

[caption id=”” align=”alignnone” width=”640”] CNC milled carbon fibre parts, thanks to Ryan.[/caption]

 

Final quadcopter layout

I finalized the layout of my drone design. It now includes a top and bottom plate, a canopy to protect the autopilot and a platform for a GPS (if needed). It also includes legs to be attached to the current 3DR arms.

In detail, the bottom plate includes 3M hole pinouts for the old and new arducopter power distribution boards. The bottom plate also has holes to attach the ESCs with zip ties, and this at three locations depending on ESC size etc.The top plate includes an extension and holes to hold a standard XBee module. There is also room and holes for the standard 3DR GPS stand. Holes in the canopy allow for access to analogue inputs and to check autopilot warning lights.

The model accepts the Xaircraft F4005 arms, and the current 3DR aluminium arms. I’m willing to adapt the model to the more common flamewheel plastic arms but I lack the measurements. If someone could provide them I can adjust the design.

The current design is drawn in FreeCAD and can easily be exported DXF format for compatibility with other CAD software or laser cutting, cnc milling.

The FreeCAD model can be downloaded using this dropbox link.

All feedback is appreciated!

 

Quadcopter frame build

I dusted of some old quadcopter hardware and have begun rebuilding my beloved ‘drone’. My last platform was a bit crowded as I crammed everything in an old CD spindle on top of the original top plate. However, this added weight and the internal layout was rather messy making maintenance difficult. On top of that I want to keep the centre of mass as low and central as possible, not stacking things up high.

So, I decided to redo the bottom and top plate to accommodate all the electronics in a nice and orderly fashion. After some initial fighting with FreeCAD I managed to get some drawings out.

[caption id=”” align=”alignnone” width=”640”] FreeCAD drawings of quadcopter parts[/caption]

I have access to the Harvard engineering facilities (thanks Don) where they have a high powered CO2 laser cutter. So today I made the first prototypes of the top and bottom frame plates out of cardboard. Below you see the laser cutter at work.

The cardboard is amazingly stiff so this allowed me not only to check the location of all the mounting holes but actually build the frame. Although it is not flight ready it does give me a far better idea what the final result will be and where I can improve upon it. Go go for cardboard prototying I would say.

[caption id=”” align=”alignnone” width=”640”] Assembled cardboard quadcopter centre plates[/caption]

Pagination


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