F2A or FAI speed is the premier speed event flown locally and at world championship level. It can be the most expensive and is definitely the most technically demanding of all the speed classes. Purpose built engines and models are the go here, no compromises at this level.
Over recent years models have evolved into single winged, side mounted streamlined speed machines. Nothing is there that isn’t necessary. Wings are made from strong aluminium formed to an airfoil section only a few millimetres thick. The bodies can still be made from wood or more up to date composites such as glass and carbon fibre.
Engines are purpose built with a maximum capacity of 2.5cc. Full length tuned exhaust systems are used to extract maximum power from these speed demons at over 40,000 rpm. World championship speeds are around 300kph.
These things will definitely get your attention, and well worth the trip to our field at Old Wells Road Seaford.
CLASS F2A – SPEED MODEL AIRCRAFT
|4.1.1.||Definition of a Speed Model AircraftModel aircraft in which the power is provided by a piston motor and in which lift is obtained by aerodynamic forces acting on the supporting surfaces, which remain fixed in flight except for control surfaces.|
|4.1.2||Characteristics of a Speed Model Aircraft|
|Maximum swept volume of motor or motors||2.5 cm3|
|Minimum total area (St)||2 dm2/cm3 swept volume of the motor(s)|
|Maximum loading||100 g/dm2|
|Maximum wingspan||100 cm|
|To determine the wingspan of asymmetric model aircraft the thrustline of the model aircraft is used. Refer Sporting Code Volume ABR Section 4C paragraph 1.4.5.The model aircraft must take off from the ground.A silencer is compulsory. Minimum internal volume 50 cm3. Maximum tailpipe internal diameter 6 mm.
An effective shutoff is compulsory so that the duration of high level noise can be limited to 20-30 seconds per flight.
Rule B.3.1. of Section 4B does not apply to class F2A.
|4.1.3.||FuelFuel to a standard formula for glow plug and spark ignition motors will be supplied by the organisers. Its composition shall be 80% methanol, 20% castor oil.Note: Fuel for compression ignition motors is not restricted.
Before each attempt for an official flight the fuel tank must be rinsed (washed out) with standard formula fuel.
|4.1.4.||Diameter of Control LinesOnly two line control is allowed, minimum control line diameter is 0,40 mm with a tolerance of minus 0.011 mm.|
|4.1.5.||Length of CourseThe measured distance covered by the model aircraft must be at least one kilometre. The radius of the flight circle must be 17.69 m. ( 9 laps = 1 km ).|
|4.1.6.||Line Tests (to be made before each attempt for an official flight)The radius is measured from the axis of the pivot on the pylon, to the axis of the propeller. Where two propellers are employed, the axis of symmetry is taken as the reference for measurement.A load test shall be applied to the assembled control handle, lines and model aircraft equal to 50 times the weight of the model aircraft and this test shall be applied separately to the safety strap when attached to the competitor’s wrist.
In each case the pull shall be applied three (3) times, slowly increasing to maximum load and releasing rapidly. The pull test should be made on the handle grip, not near the point of attachment of the lines (see sketch ).
The diameter of the lines shall be checked at random distances on at least three points along the length of each line.
|4.1.7.||Control Handle and Pylon ForkA pylon with supports as shown in the sketch, will be placed at the disposal of the competitors by the organisers. It is compulsory that a pylon fork and control handle of standard dimensions as specified, be employed. The distance between the flexible point of attachment on the control handle and the point of contact of the horizontal bar on the fork shall be a maximum of 6 mm. The horizontal bar (handle pivot) must be in continuous contact with the pylon fork during the official flights.The pylon fork shall be infinitely adjustable between 1100 mm and 1600 mm from the ground and be steadily fixed to the ground surface. Mandatory dimensions are shown in the sketch. The pylon fork in its highest position may not deflect more than 20 mm when it is subjected to a horizontal pull test of250 N.
No intentional twisting and/or linking of the two lines together shall be permitted from the point of exit of the model aircraft to the control handle. The lines shall be separated by at least 5 mm at the point of exit from the model aircraft and at least 25 mm at the handle.
The lines must be round in cross-section and may not have any liquid or coating material applied.
A safety strap connecting the competitor’s wrist to the control handle must be provided by the competitor and used during all flights.
|4.1.8.||Definition of an AttemptIt is considered an attempt when the pilot does not engage the control handle in the pylon fork within 3 minutes after the starting signal.|
|4.1.9.||Number of AttemptsIn the case of an unsuccessful first attempt for an official flight, the competitor is entitled to a second attempt.|
|4.1.10||Definition of an Official FlightThe flight is official when the timekeepers start the watches.|
|4.1.11.||Number of FlightsEach competitor is entitled to three official flights.|
|4.1.12.||Number of HelpersTwo helpers and the team manager are admitted to the contest area. A pilot may start and adjust his own motor and at most one other motor as a helper. Only team members (including the Team Manager) are allowed to start and adjust the motor(s).In case of an incomplete national speed team supporter(s) may act as helper(s) provided that he (they) is (are) registered as such for no more than one national team from the beginning of the contest through its close, and provided that the team member(s) plus helper(s) do not exceed three persons.|
|4.1.13.||Starting of TimingThe timing commences officially when the competitor has placed his handle in the pylon fork and the model aircraft having made 2 complete circuits again passes the height marker on the edge of the circuit directly opposite the timekeepers.|
|4.1.14.||Height of FlightDuring the timing of an official flight, the flying height must not be less than one metre and not more than 3 metres.|
|4.1.15.||Cancellation of the FlightA flight is cancelled when:|
|a)||any physical effort for the purpose of increasing the speed of the model aircraft during an official flight is applied by the pilot.|
|b)||if at any time during the speed course the model aircraft exceeds a height of 6 metres or sustains a height in excess of 3 metres or less than one metre for more than one lap.|
|c)||continuous contact is not maintained with the pylon fork during the official flight.|
|d)||jettisoning occurs during the official flight.|
|4.1.16||Number of Timekeepers and Judges|
|a)||The time shall be taken by either three timing officials equipped with 1/100-second resolution digital stopwatches or by an optical electronic system with equal or better resolution or accuracy. For World and Continental Championships this system must be duplex so that the duplex system serves as the required backup system. For other contests, the required backup for a single system may be by some other electronic device or by two manual timekeepers.|
|b)||Speed judges, at least two in number, shall be responsible for observing the conduct of the pilot and the altitude of the flight.|
|c)||For World and Continental Championships, a senior judge will be appointed to supervise the conduct of the timekeepers and judges.The senior judge will be selected from a list of persons who are nominated by NACs for their proficiency and experience and approved by the CIAM.|
|a)||The individual times recorded by each timing official and/or by an optical electronic system shall be recorded in writing and retained by the senior judge or other official.|
|b)||Times recorded should be handled as follows:|
|i)||In the case of manual timekeepers, the mean time of the three stopwatches shall be taken to calculate the result, unless:a) One of the stopwatch times differs from the closer of the other two by more than 12/100 seconds, or the official reports that he made a mistake. In this case the mean time shall be calculated from the other two stopwatch times.b) Two stopwatch times differ by more than 12/100 seconds from the middle one, or two officials report a mistake. In this case this fact should immediately be reported to the competitor or his team manager. The competitor then has the choice of using only the remaining stopwatch time to calculate his result, or to be allowed an attempt. His decision must be given to the F2A Circle Marshall without delay, and is irrevocable.
c) No rounding off of decimals should be made when calculating the mean time. The time thus obtained for calculating the speed should be recorded and retained.
|ii)||In the case of an optical electronic system, the senior speed judge should check the result by looking at the logged individual lap times of the official flight, as well as the laps before and after the official flight. If there is any anomaly, the backup system should be consulted. If the backup system is manual and both timekeepers report a mistake (they may have timed one lap short), the competitor should be given a replacement attempt. If the backup time, either manual or secondary electronic, is within 12/100 of the primary system time, the primary system time is used. If the backup time, either manual or secondary electronic, differs by more, but is in itself consistent, its time should be used. If an uncertainty in excess of 12/100 seconds remains, then the competitor has the choice of choosing the slowest recorded speed or being allowed a replacement attempt. His decision must be given to the Circle Marshal without delay, and is irrevocable.|
|c)||The result of the speed in km/h shall be calculated by dividing 3600 by the time according to b), and then taken to the nearest lower 1/10 km/h.|
|d)||The best speed attained during the three flights is used for classification. In case of a tie, to separate the fliers, the second best speed, and if still a tie, the third best speed is used.|
|e)||The three first positions are subject to rechecking of the declared model aircraft characteristics.|
|4.1.18.||International team classificationTo establish the national team scores for the team classification, add together the best speed attained by each individual member of the team. In a case of a team tie, the team with the lower sum of place numbers, given in order from the top, wins. If still equal, the best individual placing decides.|