Tuesday, 25 September 2012

Passing the time

Over the last few months I've been taking the time to learn about something that has always been of interest but was unfortunately difficult to indulge due to living in the middle of a city.  Well actually more than one thing but they're all fairly intertwined.

As a child I'd always been very interested in radio controlled thing... pretty much anything that moved and could be controlled was cool, but things that could fly, well now, that was super interesting!  As an adult and having the means I've now had the chance to start indulging!

The other side of RC aircraft is that you often have to either build of assemble these things which in my mind is as much fun as the actual flying.  There is something extraordinarily gratifying about taking something in it's component parts and assembling them to a state where they will not only fly, but fly well.

I started the process with attempting to build a small glider out of balsa wood and taking the motors off a small F22 RC toy... this ended in abject failure.  The reason for this failure was unknown to me and yet to be learned.  Well actually there were multiple reasons - wood too heavy, wings not big enough, centre of gravity all wrong.  Informed hindsight can be a damning thing sometimes!

Of course the next logical step was to up the complexity odds... or not.  Watching videos on Vimeo got me a bit interested in Quadrotor helicopters, specifically this one:

mwc quad - fiberglass frame from warthox on Vimeo.

So doing the standard guy thing, I took the suggested parts list from www.quadframe.com and bought them with the absolute bare minimum experience in either the electronics or the radio gear.

The process of building was as much about learning about the technologies involved as it was putting the stuff together.  It also gave me the opportunity to re-learn my soldering skills.

Quadrotors or quadcopters are very clever things that rely on the torque from the motors for yaw and motor speed for pitch and roll.  They have small electronic gyroscopes on the controller board that help to damp out any instabilities but they need to work in unison with the motors speed controllers which unfortunately mine didn't.  The end result for me was that any large control inputs resulted in a large oscillation and having it fall out of the sky.

Not having the disposable cash has meant that I haven't been able to revisit the project but it's certainly on the books for very soon.

I did manage to get it up and flying though and got a fair amount of joy out of it but I did manage to chew through propellers a tad faster than I might've liked.  Here's a vid of it in flight.  You'll see at a couple of points what it looks like when the oscillations kicked in.  To try to minimise the damage I put some aluminium rods on the bottom and an old helicopter canopy on it to keep oriented whilst I was learning.

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