I wanted to add the official rule book from the FAI website to here so that I can share, but it seems like the file of 1.4mb is too big to upload here.

Here's the link address:
http://www.fai.org/downloads/ciam/SC4_F3Helicopters_2015

F3C:

The rule book contains all the rules and regulations of the model required. Here's a basic summary as of 2015:
- 6.5kg max AUW(All up weight)
- 250dm2 main rotor size (~800mm blades max depending on your rotor head width)
- 51v max (12S Lipo)

Each competitor has 9 minutes to complete schedule P which will be flown in front of a panel of judges. After every competitor has completed a single round of flight, the scores will be tabulated and ranked accordingly. After 4 rounds, the ranked scores(not the actual score from each flight) will be added to come up with a table which the top 15 pilots will do 3 rounds of flying using the more challenging schedule F.

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