F1Q in a nut shell
The only limitation is the battery’s weight (including leads). Lithium Polymer batteries can weigh up to 90 grams, Nickel based batteries up to 120 grams. (They are practically obsolete).
There are no area or loading requirements.
There is no BOM requirement.
Motor runs are up to 25 seconds. In practice 15 seconds are sufficient. There are 7 official rounds (remember – this is an FAI event) followed by flyoffs. The max is set at 3 minutes for all flights. In the flyoffs (again FAI specs – 10 minute windows, two timers etc.) the motor run is cut 5 seconds each consecutive flight, till reaching 5 seconds, while keeping the max at 3 minutes. So if the motor run is 15 seconds in the 7 regular rounds, the first flyoff will have a 10 seconds motor run, and all the following 5 seconds motor runs. And if one start with 20 seconds motor runs, the first flyoff will have a 15 second motor run etc.
These rules can be found on the official FAI site. (Just Google FAI free flight.)