Saturday, 3 January 2015

Multicopter, airframe changes (Part 2)

After my initial flights with the first incarnation of the multicopter I decided a few changes were necessary.

The square shape made for a machine that was a bit hard to keep up with in the air. Despite my making the two forward legs black when looking towards the sun the whole thing was pretty much black anyway, in silhouette, and it was difficult to sort out which way was forward. This can be a problem with a remote controlled hovering machine. Also, with the camera looking forward it was difficult to not get the rotors in shot. 

However, Thingiverse the 3D printer enthusiasts file sharing site, had the answer. I found a design by someone called Gyrobot who had created Spyda. This design uses the same arms as my copter, (Crossfire) so these could be reused. I downloaded the STL file for the Spyda centre plate and printed 2 copies, the top and bottom of a new chassis.

These give the desired new geometry. Gyrobot has also redesigned the arms to be deeper and stronger. This would give more room in the centre of the chassis for mounting equipment. But as each arm takes over 3 hours to print I've not tried these yet.

Additionally, the Spyda design included a new battery location with a new battery holder which I've printed as well. This will now go at the back.  

I also found a new mounting case for the flight controller. The previous design I found didn't print too well for me and this one has a set of buttons tops too!

I've also ordered new motors and speed controllers. When I started I hadn't realised that the SimonK firmware is better for multicopter operation and the new speed controllers come ready 'flashed', (programmed) with the new firmware. I also ended up with some inferior motors to the ones I'll need when the camera, streaming video link and GPS capable flight controller is added. 

The next job to do though is to work out how to set up the flight controller for the new geometry. This will need a little bit of trigonometry, more on this next time. 

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