F3B Competition Rules

5.3.1. General Rules

5.3.1.1. Definition of a Radio Controlled Glider

Aeromodel which is not provided with a propulsion device and in which lift is generated by aerodynamic forces acting on surfaces remaining fixed, (i.e. not rotating or ornithopter type surfaces). Models with variable geometry or area must comply with the specification when the surfaces are in maximum and minimum extended mode. The models must be controlled by the pilot on the ground using radio control connection. Any variation of geometry or area must be actuated at distance by radio.

5.3.1.2. Prefabrication of the Models

Para B.3.1. of Section 4b (Builder of the Model) is not applicable to class F3B.

5.3.1.3. Characteristics of Radio Controlled Gliders

a) Common characteristics:

Maximum surface area (St) 150 dm2

Maximum flying mass 5 kg

Loading on the St between 12 and 75 g/dm2

Minimum radius of fuselage nose . 7,5 mm

(see template)

F3B NOSE TEMPLATE 

No fixed or retractable arresting device (i.e. bolt, sawtooth like protuberance, etc.) is allowed to slow down the model on the ground during landing.

The underside of the model must not have any protuberance other than the towhook and surface control linkages. The towhook must not be larger than 5 mm in frontal width and 15 mm in frontal height.

b) The radio shall be able to operate simultaneously with other equipment at 20 kHz spacing. Where the radio does not meet this requirement, the working bandwidth (max. 50 kHz) shall be specified by the competitor.

Any device for transmission of information from the model to the pilot is prohibited.

The competitor may use three models in the contest.

The competitor may combine the parts of the models during the contest, provided the resulting model used for flight conforms to the rules and that the parts have been checked before the start of the contest. See also 5.3.2.1.

For the sake of randomness of the starting order among the successive rounds, each competitor must enter two different frequencies, distance of 20 kHz minimum. The competitor can be called to use any of these frequencies during the contest, so long as the call is made at least 1/2 hour prior to the beginning of a round and in written form to the affected team manager.

5.3.1.4. Competitors and Helpers

The competitor (pilot) must operate his radio equipment personally. Each pilot is permitted four helpers, including the Team Manager, who must not give any turning signals near base B during tasks B and C. Any use of telecommunication devices (including transceivers and telephones) in the field by competitors, helpers or team managers is not allowed.

5.3.1.5. Definition of an Attempt and an Official Flight

a) Attempts

aa) For each task (ref. 5.3.2.1.), during the working time allocated to him, the competitor is entitled an unlimited number of attempts. An attempt starts when the model is released from the hands of the competitor or his helper(s) under the tension of the tow line. No change of model or parts of the model is allowed after starting the first attempt.

ab) The competitor is entitled to a new working time period if any of the following conditions occur and are duly witnessed by an official of the contest:

- his model in flight collides with another model in flight, or another model in the process of launch (released for flight by the competitor or his helper) or, with a launch cable during the process of launching. Should the flight continue in a normal manner, the competitor may demand that the flight in progress be accepted as official, even if the demand is made at the end of the original working time

- his model or launch cable in the process of launch collides with another model or launch cable also in the process of launch (released for flight by the competitor or his helper), or with another model in flight. Should the flight continue in a normal manner, the competitor may demand that the flight in progress be accepted as official, even if the demand is made at the end of the original working time

- his launch cable is crossed or fouled by that of another competitor at the point of launch of his model (released for flight by the competitor or his helper).

- the flight has not been judged by the fault of the judges or timekeepers.

- in the case of an unexpected event, not within the control of the competitor, the flight has been hindered or aborted.

For all cases described above the competitor may demand that the flight in progress in which the event occurred will be accepted as official. Note is made that in the event the competitor continues to launch or does a relaunch after clearing of the hindering condition(s) he is deemed to waive his right to a new working time.

ac) When a competitor obtains a new working time period, and his model has been damaged beyond repair during the attempt where he obtained this new working time, he is entitled to continue flying the current round with his second model, and this notwithstanding rule 5.3.2.1.

This rule applies only when the damage inflicted to the model is directly linked to the incident that gave the right to the reflight.

b) Official Flight

The official flight is the last flight performed during the working time.

c) Additional Attempt - Group Scoring

In case of additional attempts in Task A (Duration) during a round or Task B (Distance) during a round, the pilots entitled to that additional attempt must fly within a group that is not complete in number or in one or more groups newly formed. If not possible due to clash of frequencies, those entitled to another flight fly within their group once more. The better of the two results will be the official score except for pilots who are allowed another attempt. For those the result of the repetition is the official score.

5.3.1.6. Cancellation of a Flight or Disqualification

a) Unless otherwise specified a flight in progress will be annulled for an infraction of any rule. In the case of intentional or flagrant violation of the rules, in the judgement of the Contest Director, the competitor may be disqualified.

b) The flight in progress is annulled if the model loses any part during the launch or the flight time. The losing of a part during landing (i.e. in contact with the ground) is not taken into account.

c) The competitor is disqualified if the model is controlled by anyone other than the competitor.

d) If the model touches either the pilot or his helpers during landing manoeuvres of task A, no landing points will be given.

e) In case of hand or pulley towing the launching device (except the launching cable with or without any device of maximum 5 cm3 or 5 grams) must not be thrown by the competitor or his helpers, under penalty of cancellation of flight.

f) In case of launching by an electrical powered winch, the upwind turnaround device must be fixed safely to the ground. The flight is cancelled and no further attempt is permitted if the pulley comes loose from its mounting support or the turn around device is torn out of the ground.

g) In the case of launching by an electrically powered winch, the ejection of any part of the winch (excluding parts of the line) during its operation leads to cancellation of the flight, and no further attempt is permitted.

5.3.1.7. Organisation of Starts

The competitors shall be combined in groups with a draw, in accordance with the radio frequencies used, to permit as many flights simultaneously as possible. The draw is organised in such a way that, as far as possible, there are no competitors of the same nation in the same group.

The composition of the groups must be changed every round in order to have different combinations of competitors. For duration (task A), there must be a minimum of five pilots in a group. For distance (task B) there must be a minimum of three competitors. For task C (speed) a group may consist of a minimum of eight competitors or all competitors.

The result of a group is annulled if only one competitor is not entitled to a new working time. In this case, the group will fly again and the result will be the official result.

The flying order of different groups is established with the draw too. A different starting order shall be used for each round.

The competitors are entitled to 5 minutes of preparation time before the starter gives the order to count off working time.

5.3.1.8. Organisation of Contests

For transmitter and frequency control see Section 4b, para B.8.

The official will issue the transmitter to the competitors only at the beginning of their preparation time, according to 5.3.1.7.

Sighting apparatus, winches or any device constituting an obstacle, should be placed on Base A and Base B, a minimum of 5 metres from the safety line for Task C. Apparatus for judging the safety line in Task C shall be placed a minimum distance of 5 metres from Base A or B outside the course.

5.3.1.9. Safety Rules

The organiser must clearly mark the boundary between the landing area and the area assigned for other business (safety area).

Except in the circumstances described in paragraph 5.3.1.5 a) ab) alineas 1, 2, 3, and 5, after release of the model from the hand of the pilot or helper and until the model comes to rest, the contact of the model with any object (earth, car, stick, plant, line, etc.) or a person within the safety area will be penalised. The number of contacts during one flight does not matter (maximum one penalty for one flight). The penalty will be a deduction of 100 points from the competitor’s final score and shall be listed on the score sheet of the round in which the contact occurred.

5.3.2. RULES FOR THERMAL SOARING CONTESTS

5.3.2.1. Definition

This contest is a multi-task event for radio controlled gliders, which includes three tasks:

A) Duration

B) Distance

C) Speed

The combination of Task A, B and C constitutes a round. A minimum of two rounds must be flown. In the case of a World Championships each competitor is entitled a minimum of five rounds subject to the provision of rule B.11, Section 4b. At the discretion of the organiser any task may be flown first in a scheduled round.

Any single round must be completed with the same model, without any change of parts. Only the addition of ballast (which must be located internally in the model and with which the model must conform to rule 5.3.1.3.) and/or change of angles of setting are allowed.

Variation of geometry or area is allowed if actuated at distance by radio control.

5.3.2.2. Launching

General

All launching shall take place in an area as designated by the organiser with provisions made for launching into the wind. Unless otherwise specified, all launches will be made with equipment approved by the organiser or Contest Director. Contest notices shall contain a description of the launching equipment to be available and its general capabilities.

a) The launch of the glider may be one of the following means:

(1) hand towing

(2) electrical powered winch

(3) hand operated pulleys.

b) The total length of the towlines must be as follows:

a(1) Hand towing: must not exceed 175 m when tested under a tension of 2 kgf.

a(2) Electrical Powered Winch: line length must not exceed 400 metres. Upwind turn-around devices, which must be used, shall be no more than 200 m from the winch. The height of the axis of the turn-around pulley to the ground must not exceed 0,5 metre. Release of the model must occur within approximately 3 metres of the winch. An automatic means must be provided to prevent line reel from unwinding during launch.

The winch shall meet the following specifications:

a) The winch shall be fitted with a single production starter motor having an internal resistance of at least 15,0 milliohms at ambient temperature corrected to 20 0C using the formula:

R(20 0 C) = R(T)/(1 + 0,003 X (T - 20 0 C)

where R = internal resistance and T = ambient temperature in degrees centigrade.

The measurement has to be made by a digital storage instrument no less than 150 milliseconds and no more than 200 milliseconds after the test voltage is applied and during which time the motor shall have stopped rotating.

The measurement should be made using the test equipment and procedure shown in Annex 5C.

Battery voltage, current flow and voltage at the motor terminals (including any additional adjusting resistor), shall be instantaneously displayed and then recorded to enable calculation of motor internal resistance. The resistance may be attained by adding an external resistor, but the design must not allow any change of total resistance (e.g. by overbridging the resistor). Resistance of any control device does not count.

The rotor of the motor may be fitted at each end with ball or needle roller bearings. Any further change of the original motor will lead to immediate disqualification of the competitor who used it.

b) The drum must have a fixed diameter and the width between winch drum flanges shall be at least 75 mm.

c) The power source shall be a 12-volt lead/acid battery. The maximum cold cranking ampere capacity should be not more than

275 Amperes DIN, or

310 Amperes IEC, or

460 Amperes SAE.

455 amperes EN

(This fixation of the maximum cold cranking ampere capabilities is in accordance with an internal resistance of the battery of about 6 milliohms).

If the battery is controlled by the organiser the measured internal resistance of the battery should not be lower than 5,4 milliohms (6 milliohms minus 10%).

Details of battery specifications and measuring procedure are given in Annex 5C.

The battery must supply the winch motor with current through a magnetically or mechanically actuated switch. The use of any electronic device between the winch motor and the battery is forbidden.

The battery may not be charged on the launching line.

d) The motor must not be cooled, and the battery must not be heated.

e) The purpose of this rule is to prohibit the use of significant energy storage devices other than those mentioned. With the exceptions of the single winch battery, line stretch, and the small amount of energy in the rotating motor and winch drum, no energy storage devices shall be allowed. This includes, but is not limited to, flywheels, springs, weights, and hydraulic or pneumatic devices. The flywheel-like properties of the winch drum shall not be exploited.

a(3) Hand Operated Pulleys: must not exceed 175 metres when tested under a tension of 2 kgf. One end of the towline must be attached to the ground during launch.

c) The towline (which must be of non-metallic material except for linkages) must be equipped with a pennant having a minimum area of 5 dm2. A parachute (5 dm2 minimum area) may be substituted for the pennant provided it is not attached to the model and remains inactive until the release of the cable.

d) Launching operations:

(1) Hand towing: After release of the model from the towline the towring must be retrieved without delay to the handreel.

(2) Electrical powered winch: After release of the model from the towline, the towline should be rewound without delay by operating the winch, until the parachute (or pennant) is approximately 10 metres above the ground level. Then, the parachute should be retrieved by hand to the winch. A powered winch must not be operated when the towline:

- is lying on the ground and across other towlines;

- strikes another towline during launching.

During complete rewinding of the line on the winch, the parachute, when used, must be removed and inactivated.

5.3.2.3. Task A - Duration

a) This task must be completed within 9 minutes from the order of the starter, including the towing time.

b) One point will be awarded for each full second from the time the model is free flying to the time the model comes to rest, up to a maximum of 420 points (i.e. 7 minutes maximum), for each full second of flight within the working time; no points will be awarded for flight time in excess of working time. The free flying of the model commences when the model is released from the towline.

c) One point will be deducted for each full second flown in excess of 420 seconds (7 minutes).

d) Additional points will be awarded for landing, depending upon distance from the spot, marked by the organiser, according to the following tabulations:

Distance from spot(m) Points Distance from spot(m) Points

1 100 9 60

2 95 10 55

3 90 11 50

4 85 12 45

5 80 13 40

6 75 14 35

7 70 15 30

8 65 over 15 0

The distance is measured from the model nose when at rest to the spot (centre of the circle of 15 m radius).

No point will be awarded for the quality of landing.

No landing bonus will be awarded if the flight time exceeds 450 seconds (7,5 minutes).

The measured distance is rounded up to the nearest higher metre.

e) For models still in the air when the 9 minutes expire, the elapsed flight time only will be taken into consideration for scoring, without any additional points for the precision landing.

f) A classification based on decreasing number of points awarded will be compiled, called "Partial Score A" - see 5.3.2.6.

5.3.2.4. Task B - Distance (see sketch)

a) This task must be completed within 7 minutes from the order of the starter, including towing time. The trial begins only after the glider has been released from the tow.

b) When the model, in gliding flight, first crosses the Base A (imaginary vertical plane) in the direction to the Base B, the actual flight time of 4 minutes maximum starts during which the model must complete as many laps as possible from the starting Base A to the Base B and return.

c) A judge (or an audio system) announces the pilot when his model crosses the Base A and a flagman (or an audio system) is used to signal crossing of the Base B (imaginary vertical plane). The absence of a signal will indicate that the model has failed to correctly cross the base. The instruments used to check the crossing of the vertical planes must assure the parallelism of such planes. Timing or flagging shall occur when the nose of the model crosses the base.

d) Before the beginning of the working time, the model must be presented for identification at Base B. The pilot must stay within a distance of 10 m either side of Base A during the timed flight.

e) For a model which lands within 4 minutes flight time only the full 150 m laps will be counted. For models still in the air when the 4 minutes flight time or 7 minutes expires, whichever comes first, only the completed laps at that moment will be taken into account.

f) A classification based on decreasing number of total flown laps during the flight time will be compiled, and points given as described in 5.3.2.6., thus establishing the "Partial Score B".

5.3.2.5. Task C - Speed (see sketch)

a) This task must be completed within 4 minutes, from the order of the starter including towing time. The trial begins only after the glider has been released from the tow. After release of the towhook, the model must start the task at Base A within one minute. If the one minute period expires before the model has crossed Base A for the first time, flying from Base A to Base B, then the model must be landed and relaunched within the original working time period.

b) The task consists of flying the distance starting from Base A, to Base B, and conversely, four times in the shortest possible time.

c) The flight time in seconds is recorded to at least two decimal places when in gliding flight the model first crosses Base A and completes four laps of the 150 m course.

d) A flagman or an audio system announces to the pilot when the model crosses a Base (imaginary vertical plane). The absence of a signal will indicate the model has failed to correctly cross the Base. Turning or flagging shall occur when the nose of the model crosses the base.

e) During the timed flight the pilot must stay within a distance of 10 m either side from Base A.

f) After having completed the task, the model can land anywhere.

g) Models which come to rest before having completed the task will receive score zero.

h) During Task C the timed flight shall take place to one side of the safety line, whilst all judges/time-keepers shall remain on the other side of the safety line. The side which is to be flown shall be indicated by the organisers taking into account the direction of the sun, etc. The flight is annulled if, when sighted by means of an optical aid, the safety line is crossed by any part of the model.

I) After release of the towhook, when the model has crossed Base A for the first time, flying in the direction from Base A to Base B, no further attempt is permitted unless the competitor signals his intention to relaunch before Base A is crossed.

j) A classification based on increasing times to complete the four 150 m laps will be compiled, and points given as described in 5.3.2.6., thus establishing "Partial Score C".

5.3.2.6. Partial Scores

a) For each task the winner of each group receives 1000 points.

b) Partial Score A for each competitor is determined as follows:

P1

Partial Score A = 1000 X -----

PW

Where P1 = points of the competitor obtained as 5.3.2.3.

PW = points of the winner in the relating group.

c) Partial Score B for each competitor is determined as follows

D1

Partial Score B = 1000 X -----

D W

Where D1 = distance covered by the competitor as for 5.3.2.4

D W = distance covered by the winner in the relating group.

d) Partial Score C for each competitor is determined as follows

T W

Partial Score C = 1000 X ----

T1

Where T1 = time of the competitor as for 5.3.2.5.

T W = time of the winner of the relating group.

Total Score

The competitors Total Score for each round is compiled by adding the Partial Scores of all three tasks.

5.3.2.8. Classification

If only five rounds are flown, the competitor’s classification is determined by the sum of all Total Scores for each round. If more than five rounds are flown, the lowest Partial Scores for task A, B and C are omitted from the sum of Total Scores. To decide the winner when there is a tie, a whole round (three tasks) is repeated.

5.3.2.9. Site

The competition must be held at a site having reasonably level terrain, with a reasonably low probability of slope or wave soaring.

F3B FLYING FIELD LAYOUT

(left hand layout shown) 

ANNEX 5C, CLASS F3B

SPECIFICATIONS AND TEST METHOD

FOR THE WINCH BATTERY AND THE WINCH MOTOR

Standards for the Specification of the Cold Cranking Capability (See 5.3.2.2.b) a(2) c)).

The cold cranking capability of the winch battery must be specified according to one of the following standards:

275 amperes max. according to DIN 43539-02 (30s/9V at – 18°C)

310 amperes max. according to IEC/CEI 95-1 (60s/8,4V at – 18°C)

460 amperes max. according to SAE J537, 30s Test (30s/7,2V at O°F, approx. –18°C)

                    455 amperes max. according to EN 60095-1 (10s/7,5V at – 18°C)

Other standards are acceptable if evidence is provided that these standard are equivalent to one of the above-stated standards.

Test Method to Measure the Internal Resistance of the Winch Motor and the Battery (See 5.3.2.2.b) a(2) a) and c)).

The measurement of the total internal resistance of the motor (including any external resistor) and the measurement of the internal resistance of the battery are accomplished under stalled motor conditions. The motor is locked with a belt or a rope allowing rotation of the motor shaft by a few degrees. Two tests must be performed; i.e. Test H at high current (see Figure 1) and Test L at low current (see Figure 2). The notations for current and voltage are shown in Figure 3. For both tests, a calibrated resistor (0,1 milliohm +/- 0,5%) is inserted in the negative path to enable the current to be measured. For Test L, an additional resistor of approx. 60 milliohms is inserted in the positive path, and the coil of the magnetically operated switch (if used) is connected directly to the plus pole of the battery.

When presented for testing, the winch battery must be fully charged. The motor, wiring, adjusting resistor (if used), battery and battery acid must all be at or near ambient temperature.

The measuring equipment measures simultaneously the voltage of the battery (Ub), the voltage drop at the motor Um and the current I, no less than 150 milliseconds and no more than 200 milliseconds after the voltage is applied and during which time the motor shall have stopped rotating.

The total internal resistance of the motor Rm at ambient temperature T is calculated from Test H as follows:

Rm(T) = 1000 x UmH/IH

(UmH in volt, IH in ampere, Rm in milliohm),

and then corrected to 200 C by the following formula, see 5.3.2.2.b)a (2) a):

Rm (20 0 C) = Rm (T)/[1 + 0,003 x (T - 20 0 C)]

(Rm in milliohm, T in degrees centigrade)

The voltage of the battery UbH should be greater than or equal to 9 volts for a reliable test of the motor.

The internal resistance of the battery at ambient temperature T is calculated from Test H and Test L as follows:

Rb (T) = 1000 x (UbL- UbH)/(IH - IL)

(UbL, UbH in volt, IL, IH in ampere, Rb in milliohm),

and then corrected to 20 0 C by the following formula:

Rb (20 0 C) = Rb (T)/[1 - 0,006 x (T - 20 0 C)]

(Rb in milliohm, T in degrees Centigrade).

A first measurement is taken in order to check the correct functioning of the measuring arrangement, and then discarded. Three subsequent measurements should be made at high current (Test H) with an interval of approx. 30 seconds followed by three similar measurements at low current (Test L). The total internal resistance of the motor and the internal resistance of the battery is the average of the three respective results. This procedure is repeated once if the average total internal resistance of the motor is less than 15,0 milliohms and/or the average internal resistance of the battery is less than 5,4 milliohms. The motor is declared as being in accordance with the rules if its total internal resistance (first, or second average if applicable) is greater than or equal to 15,0 milliohms. The battery is declared as being in accordance with the rules if its internal resistance (first, or second average if applicable) is greater than or equal to 5,4 milliohms.

If the measurements show that the resistance of the motor is decreasing, more measurements should be carried out.

The accuracy of the measuring equipment (shunt included) shall be better than or equal to +/- 2%.

The following tapping points must be readily accessible with alligator (crocodile) clips for voltage measurements (required for a fast and accurate field test):

A) positive pole of battery.

B) negative pole of battery.

C) motor body (close to brushes).

D) motor terminal or adjusting resistor if used.

Fig. 1: Test H at high current.

Version with magnetically operated switch shown

Fig. 2: Test L at low current.

Version with magnetically operated switch shown

Fig. 3: Notations for Current and Voltage.