Introduction to the Raspberry Pi Helicopter

The Raspberry Helicopter is a hobby project to convert a radio controlled helicopter to one that is controlled by a on board Raspberry Pi. The aim of the project is to create a small helicopter that can independently fly small missions whilst visually recording key positions on its flight. As well as video the footage of the flight, it will be required to fly, take-off, land and avoid obstacles. 

This project is in the beginning of its creation cycle. I have personally never even flown a radio controlled helicopter. Yet I am confident it can be done. My idea is to use a mobile phone dongle for communications (orange £5 per month one assuming open source drivers can be found). Otherwise use a wifi dongle with a wifi mobile bridge).
Navigation will be via a GPS dongle with antenna attached to one of the usb sockets again (open source driver required). Parking sensors will be added for extra navigation, aids for landing and collision prevention.
The Pi GIPO will be hopefully be used for the flight controls using a software neutral network with input feeds from Parking Sensors and GPS.
Any existing RF control system will be retained with a manual override RF switch. This will allow the helicopter to be brought back under human control during flight.
In addition an IP camera will be added to record flight and will be attached via the RJ45 network socket.
Currently I am on the waiting list for a Pi and have budgeted around £300 for the equipment. I have a GPS dongle and mobile internet. At this point I am looking to answer some questions. (see questions sections).