Synopsis of FAI Class F3C Operation

By Horace Hagen, Chairman of the CIAM F3C Sub-committee (2006 Update)

For the FAI/CIAM F3C competition class pilots must perform complex hovering and aerobatic manoeuvres with a radio controlled model helicopter. Each manoeuvre must be executed with high precision and skill in any attitude and under all weather conditions. F3C model helicopters have a weight limit of 6kg, a maximum rotor disc area of 250dm2 and are powered by internal combustion engines with a maximum displacement of 15ccm or electric motors with a maximum battery voltage of 42 Volts. The engines/motors must be adequately silenced to meet a specified noise limit. The on-board radio control equipment, receiving signals from the competitor’s transmitter, actuates the engine throttle, main rotor lateral and longitudinal cyclic pitch, main rotor collective pitch and tail rotor pitch to guide the model helicopter through hovering and aerobatic manoeuvres.

Manoeuvre schedule A is used for the preliminary rounds and more difficult schedules B and C are used during the fly off rounds. Each schedule contains three hovering manoeuvres that are performed directly in front of the judges over a designated helipad layout. Aerobatic manoeuvres are performed in a window that extends 60 degrees to the left and right of a centre line, and at an elevation of no more than 60 degrees. A prescribed aerobatic manoeuvre must be performed each time the model helicopter crosses the centre line. Aerobatic manoeuvres consist of a combination of loops, rolls, pirouettes, lines and stall turns. Aerobatic manoeuvres or parts thereof performed outside of the window are penalised by loss of points, proportional to the degree of infraction. The hovering manoeuvres are flown at a distance of 15 metres from the judges. The aerobatic manoeuvres are typically flown at 100 metres in front of and parallel to the judges’ line.

Each competitor’s performance is assessed by a panel of judges who award marks between zero and ten (0.5 increments) for each manoeuvre. Judging is based on four basic criteria: Precision , Smoothness and Gracefulness, Positioning and Display/Size of manoeuvres. Points are subtracted for various types of defects observed by the judges, the severity of these defects, and the number of times the defects are observed.

Each competitor participates in four preliminary rounds, of which the best three flight scores determine his/her placing. The F3C class is a team as well as an individual competition. FAI member countries may enter a team with a maximum of three competitors as a national team for World- and Continental Championships. Team results are based on the sum of each country’s team members’ preliminary round scores and determine the F3C World Champion Team. The top 15 pilots of all competitors then participate in three fly-off rounds to determine the F3C World Champion.