Below are the FAI rules for setting speed records.
Speed Records in a Straight Line 5.3.1.
a) For model aircraft of the Free Flight sub-classes, the record is measured over a base of 50 m for model aircraft with elastic type motors and of 100 m for model aircraft with piston type motors.
b) For radio controlled model aircraft, the base must be 200 m, except for airship indoor records, where the base must be 25 metres.
c) The course must be flown in both directions within 30 minutes. For all radio-controlled model aircraft, it must be traversed in both directions without any intermediate landing.
d) For a base of 200 m, the altitude of the model aircraft must remain below 35 m and above 5 m during the 100 m entry and 200 m course. These altitudes are measured from the point where the pilot is standing. For other bases the descent must be less than 15% of the base.
e) The dossier of the record must include a certified measurement of the course and a statement of the methods used to determine altitude and speed. Note: For radio control speed record attempts, the model aircraft must be fitted with a device to stop the motor by radio control.
a) The timing of speed records must be accomplished by timing instruments approved by the organising National Airsports Control. If electronic stopwatches are used, timekeeping must be effected by two timekeepers, utilising devices which register to at least 1/100 of a second. The difference between the times registered by the two timekeepers must not exceed 0.05 second. Automatic and other electronic timing devices which register a single time are allowed, provided the system is properly documented in the dossier and approved by the NAC of the claimant(s).
b) For speeds above 300 km/h, manual activation of timing devices is not permitted. Only automatic means of timing which eliminate human error factors are permitted and must be certified accurate within 1/100 of a second and +/- 0.5 metre for position on both sides of the course.
c) The data that the Directing Official signs must be the data generated automatically at the time of the flight. Hand-written data is not acceptable. These data must be included in the record attempt dossier (par. 7.3)
d) The speed of a run is calculated by dividing the measured time over the 2 runs by 400 metres. e) The measured speed will be rounded to the lowest 0.1 km/h. 5.3.3. Minimum Difference between Consecutive Records The minimum increase of a speed record in a straight line is 1%.
5.3.4. Safety Distances For records with RC airplanes or helicopters, the closest point of the course to the pilots and all the officials shall be 100 metres minimum