Back in December 2012 I helped The Register with a test flight for their “LOHAN” project. Sadly, that flight ended up very wet in the English Channel due to reality completely disagreeing with the predicted flight path, after the Met Office failed to fly any balloons themselves that day. The results was that a weather front arrived 6 hours earlier than the predictions suggested, taking the flight much further south and ditching 10 miles offshore.
So this flight was essentially a re-run of the original flight, but with some additions. On my side that meant adding a Raspberry Pi tracker to the nose of The Register’s “CHAV” paper plane, complete with Pi camera module to capture stills for transmission and a video of the landing. Now the UK laws don’t allow us to fly the plane from a balloon, so it had a tethered parachute plus a drogue chute to make sure the main one deployed. In the end, the release system didn’t work so the aircraft remain attached to the main payload throughout the flight until it hit a tree on the way down.
The Pi camera was fixed inside the nose cone, behind a small hole so it could see out:
I happened to have some RPi stickers, just about the right size to adorn the side of the plane 🙂
There was no room in the nose cone for the Pi, so this went into the front of the fuselage. It was a very tight fit. I’m sure we’d like to say it was planned that way but no, it was just good fortune that there was just enough space for the Pi, tracker board, regulator and batteries!
The standard camera cable was too short so I ordered some longer ones, opting for a 300mm cable. The camera worked just fine with this.
The launch itself went well, and with the flight path not going too far away we had time to stop en route. The only problem was that we had to reboot my car PC and it decided to install 37 Windows updates!!! Suffice to say that this errant behaviour is now disabled (and soon I’ll have a Pi-based car tracker anyway). You can see the infamous screen here:
We waited for the plane to release, but it never did (we later found out that the triggers all worked but the release system didn’t cut the line). So the entire flight come down underneath what was now a rather under-sized parachute, landing in trees. We’d opted for what turned out to be the wrong landing spot, so we didn’t see it come in to land.
When we arrived I started to upload pictures received from the Pi radio transmitter, and I could quickly see that it was in a tree just from those! When I arrived near said tree the others were there already, cutting down branches to free the plane.
The balloon and parachute came down easily too, so everything was recovered. Overall a pretty successful flight – now just the igniter system needs to be sorted.