F5B

F5B is a type of radio control electric model aircraft contest that consists of doing as many laps as possible between 2 poles 150 meters apart in 200 seconds followed by 10 minutes of thermalling, and then landing on a 30-meter landing circle.

It is a competitive discipline in radio-controlled electric-powered model aircraft, governed by FAI (Fédération Aéronautique Internationale). It combines speed (or distance), duration, landing (or precision), and energy management. Pilots fly high-performance gliders through a challenging course consisting of timed speed runs, distance tasks, and thermal gliding. The goal is to optimize battery usage while achieving maximum performance. Models are lightweight, aerodynamic, and equipped with powerful electric motors and high-efficiency propellers. Pilots must skillfully control their aircraft to excel in multiple segments, requiring both technical expertise and strategic planning. F5B events showcase advanced engineering, pilot skill, and the excitement of high-speed, high-precision flying.

The Rules (F5B sporting code) of 2024 can be found here

Speed (or distance): In a timeframe of 200 seconds (3min and 20s) from the moment the model is launched one needs to complete as many 150 meter 'laps' as possible. Each lap scores 10 points. You can use the motor to climb a maximum of 10 times but all laps must be completed with the motor off.

Duration: At the end of the distance task you have to fly for a further 600 seconds (10 minutes). Each second airbourne scores 1 point but 3 points are deducted for every second of motor you use. You also lose a point for every second you fly in excess of the 10 minutes.

Landing (or precision): The flight ends when the model comes to rest on the ground. A landing bonus of 30 points is added if the nose of the model is within 5 metres of a pre-determined landing spot. 20 points are added if the nose is within 10 metres, and 10 points if it is within 15 metres.

Energy management: The amount of energy in one flight must be stored by a logger and the maximum to be used is 1750 W*min. Anything over this will result in a deduction of 1 point per 3 W*min over 1750 W*min.

The results of most year's Belgian competitions can be followed on the specialised website managed by Jacques Sansdrap. Thnakf to him for the very valuable efortsd.