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4.4. |
CLASS F2D - COMBAT
MODEL AIRCRAFT |
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4.4.1. |
Definition of a
Combat Event
A combat event is a contest during which eliminating heats are
followed by a final in which two competitors with their model
aircraft fly in the same circle at the same moment for a
predetermined time, the object being to cut a streamer attached on
the longitudinal centre line of the opponent's model aircraft,
points being awarded for each cut taken. |
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4.4.2. |
Definition of a Combat Model Aircraft |
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a) |
Model aircraft in
which the propulsion energy is provided by a piston motor(s) and in
which lift is obtained by aerodynamic forces acting on surfaces
which remain fixed in flight, except for control surfaces. |
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b) |
The longitudinal
centre line shall be defined as the axis of the propeller in case of
a single engined model aircraft and the axis of symmetry in the case
of multi-engine model aircraft. |
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4.4.3. |
Combat Site
A combat site must consist of two concentric circles which shall be
marked on the ground. |
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a) |
The
flight circle: radius 20
metres |
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b) |
The
centre (piloting) circle: radius 2
metres. |
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The flight circle
must be laid out on grass. The centre piloting circle may be laid
out on grass or any other material having a maximum radius of 4
metres. |
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4.4.4. |
Competitor
The pilot, who shall be the entrant and known as the competitor, may
employ a maximum of two mechanics in any one heat. (In exceptional
circumstances of wet or extremely windy weather, an additional
helper may be used as a streamer holder and must perform no other
function for the duration of that combat period).
For World and Continental Championships, the helpers, a maximum of
six other than team members or the team manager (or assistant team
manager), must be registered for no more than one national team,
from the beginning of the competition throughout to the end. During
active combat periods, the pilot and his mechanic(s) must wear
protective headgear fitted with an effective retaining strap. |
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4.4.5. |
Characteristics of a Combat Model
Aircraft |
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Maximum surface area: |
150 dm2 |
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Maximum weight: |
5 kg |
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Maximum loading: |
100 g/dm2 |
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Maximum swept volume of motor(s): |
2.5 cm3 |
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Engines with glow
plug ignition shall have their exhaust port(s) connected to
silencer(s) (one or two), consisting of a simple chamber with one
circular cross-section outlet aperture of 8mm (1) or 5,65 mm (2)
diameter(s) opposing the exhaust port connection. The minimum total
volume of the exhaust system shall be 12,5 cm3. In the case of two
exhausts, each silencer shall have a minimum volume of 6,0 cm3. The
maximum total length of the exhaust system from exhaust port(s) of
the cylinder to and including outlet(s) is 15 cm.
The motor shall have a maximum effective venturi diameter of 4,00 mm
(see 4.4.6.d for field verification).
A safety wire with a minimum diameter of 0,5 mm must be attached
between the bellcrank bolt (axle) and the engine(s) so as to
withstand a minimum pull load of 100 N.
The model aircraft shall not carry any artificial aid intended to
assist the cutting of the streamers. The model aircraft shall be
equipped with a device specially designed to retain the streamer
which shall be fitted on the longitudinal centre line and
sufficiently strong so that the streamer shall not become detached
under normal flying conditions.
Standard fuel shall be supplied by the organisers to be used for
practice (minimum 0,5 ltr) and competition (sufficient to complete
rounds) to the following formula: 10% nitromethane 20% castor oil
lubricant (first pressing) 70% methanol. A reasonable charge may be
made for the fuel.
Note: Fuel for compression ignition engines is not restricted.
Rule B.3.1. Section 4B does not apply to class F2D. |
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4.4.6. |
Controls - Technical Verification |
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a) |
Line
length: |
The length of the
control lines must be 15,92 +/- 0,04 m. It is measured from the
inboard face of the grip of control handle to the longitudinal
centre line of the model aircraft. |
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b) |
Control
System: |
Two multi-strand
control lines of a minimum diameter of 0.385 mm (no minus tolerance)
must be used. No free ends capable of entangling an opponent's
lines, and no line splices, are permitted. A safety strap connecting
the competitor's wrist to the control handle must be provided by the
competitor and worn at all times while his model aircraft is flying. |
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c) |
Line
Tests: |
Before each heat
any sets of lines which may be used must be checked for length and
diameter. A pull test shall be applied to the assembled handle(s),
control lines and model aircraft for all equipment to be used in
that heat. The pull test shall be equal to 150 N. |
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d) |
The motor shall be
naturally aspirated via a single round intake. For field
verification before a flight this intake opening shall be checked
with a simple plug gauge per the following sketch: |
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Any interconnecting
chamber between the air intake and the induction port of the motor
shall have a maximum volume of 1,75 cm3. This clearly prohibits
sub-piston induction for supplementary air intake.
Any venturi insert designed to accomplish this must be positively
retained so that it may not accidentally become dislodged during the
heat. |
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e) |
The silencer(s) on
the glow engines shall have a round exhaust the rearmost end of
which will not admit a 8,05 mm (one silencer) or 5,65 mm (two
silencers) diameter plug gauge(s). |
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OR

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Silencer
measurements will also measure:
1) the volume of the silencer by filling with an
appropriate liquid (oil or other);
2) inspecting the silencer's internal compartment to determine
if it is truly "simple", i.e. it is an empty container with no
internal components, a single exhaust opening and one allowable
pressure tap directly connected to the fuel tank, of maximum
diameter 2 mm. No other openings or vents are allowed. |
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4.4.7. |
Number of Model Aircraft |
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a) |
A competitor may
have processed a maximum number of model aircraft equal to twice the
number of heats a competitor may have to fly (excluding reflights).
Only one model aircraft specification certificate is required for
each design of model aircraft presented by each competitor. |
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b) |
Each competitor
shall be permitted a maximum of two model aircraft, two handles, two
pairs of lines and two engines in each combat heat. If the reserve
model aircraft is used, the streamer or its remaining parts must be
transferred to the reserve model aircraft. Handle plus lines for the
reserve model aircraft must be placed just outside the centre
circle. |
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c) |
Engines, control lines and handles may
not be replaced or interchanged during the combat period. |
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4.4.8. |
Streamer
The streamer shall consist of double weight crepe paper (80 g/m2) or
any replacement of equivalent strength, not less than 2,25 m or more
than 3 m long and 3 +/ 0,5 cm wide, fixed to a sisal string of 2,5 m
minimum length. All streamers must be of the same length. There
shall be a clearly visible ink mark 2,5 m from the junction of the
string and streamer. The streamer shall be attached to the model
aircraft in such a way that the ink mark is level with, or behind,
the rearmost portion of the model aircraft (see sketch). The
attachment part of the string shall have a minimum length of 0,75
metre.
The attachment end of the streamer shall be reinforced on either
side by tape approximately 2 cm wide affixed diagonally to the
length of the streamer with one at right angles to the other and
extending for a maximum of 5 cm. An additional fibre/fabric
reinforced tape 2 cm wide is affixed across the streamer (see detail
below). |
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STREAMER AND ATTACHING STRING SPECIFICATIONS |
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The colour of the
streamer must be different for the two competitors in the heat. Each
pilot/pit crew shall be issued with a streamer at the start of the
heat by the judge assigned to that competitor. A second streamer
will be available from this judge when needed. |
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4.4.9. |
Method of Starting |
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a) |
All signals shall be both acoustic and
visual. |
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b) |
During the starting
period the launching positions must be separated by at least a
quarter of a lap. The first named competitor in the draw shall have
the choice of streamer colour and the other the choice of starting
position. |
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c) |
The motor(s) must be started by
flicking the propeller by hand. |
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d) |
A first signal,
given by the Circle Marshal, shall signify the beginning of the 60
seconds period when the mechanic(s) or the pilot have the
opportunity to start, run and adjust their motors. |
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e) |
A second signal,
given by the Official Timer, shall signify the beginning of the
combat period on or after which the model aircraft may be launched. |
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f) |
From the moment the
Official Timer has given the signal to launch the combat heat lasts
for four minutes. |
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g) |
When the Circle
Marshal is satisfied that each model aircraft has completed two
level laps, anticlockwise, separated by approximately half a lap, he
will give a signal that combat may commence. |
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h) |
Combat may begin
after a restart signal from the Circle Marshal following an
interruption when one or both model aircraft have been grounded.
This signal shall be given as soon as the Circle Marshal is
satisfied that there is approximately half a lap separation between
the two model aircraft. |
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4.4.10. |
Termination of the Contest |
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a) |
The Circle Marshal shall give an acoustic signal to terminate the
combat heat four minutes after the
signal to launch, i.e. five minutes after the first signal to run and
adjust motors. |
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b) |
The same acoustic signal shall be given if the heat has to be
terminated due to disqualification of one
or both competitors or for any other reason. |
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c) |
The Circle Marshal shall signal both pilots to fly level and
anti-clockwise and to cease combat when
both streamer strings have been cut. If one pilot has only the string
remaining he may request the
circle marshal instruct both pilots to fly level and anti-clockwise and to
cease combat. This decision
may not be reversed, once made. |
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4.4.11. |
Method of Scoring |
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a) |
Scoring shall commence from the signal to launch and continue for the
four minute period. |
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b) |
100 points shall be awarded for each distinct cut off the opponent's
crepe paper streamer. There is a
cut each time the model aircraft, propeller or lines fly through the
opponent's streamer resulting in
paper particle(s) becoming detached from the streamer. |
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c) |
A cut must contain at least one part of the paper streamer. A cut that
contains string alone will not
count. |
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d) |
Should the string become
detached from the model aircraft while airborne the competitor shall
be
penalised by 100 points and must immediately on a signal from the Circle
Marshal land and replace
the streamer. Ground time will be counted from the moment of such a signal
being given.
If after a mid-air collision no streamer can be found and the streamer
retaining device is missing or
bent, then, with the permission of the judges, it is acceptable to
continue the heat without replacing the
streamer. |
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e) |
One point shall be awarded for each whole second that a model aircraft
is airborne during the four
minute period. |
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f) |
Each whole second of stay on the ground of the model aircraft shall be
penalised by 1 point. In the
case of a model aircraft fly-away, with or without lines, this ground time
shall commence from the
moment of such fly-away (see 4.4.12.b)). |
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g) |
Each warnable offence (see 4.4.14.) shall be penalised by the deduction
of 40 points from the
competitor's score. |
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h) |
Should the mechanic(s) damage the streamer, or the model aircraft cut
its own streamer, whilst the
model aircraft is on the ground the mechanic(s) must replace it with a new
streamer. If they launch the
model aircraft without so replacing it, the competitor shall be penalised
by 100 points. Ground time will
be counted while the model aircraft is airborne with the damaged streamer. |
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4.4.12. |
Attempts
Only one attempt will normally be allowed to complete a combat heat except
for when: |
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a) |
A streamer breaks or fails to unfurl from the rolled state. |
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b) |
In the event of a model aircraft fly-away, as a result of the lines
having been severed by his opponent's
model aircraft, lines or engine, in which the model aircraft and streamer
may not be retrievable due to
the distance flown, the circle marshal asks the affected pilot whether he
wants a new attempt or not.
The affected pilot must respond immediately, without consulting others
about the status of the heat. If
the pilot wants to continue the flight he must use a new full-length
streamer.
The pilots should be informed before the beginning of the competition
where the fly-away area is
defined. This area should be clearly defined by the organisers. |
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c) |
In the event of a line tangle resulting in the control line(s) breaking
and only one model aircraft being
grounded, making it impossible to clear the line tangle. |
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d) |
If, as a result of a line tangle, an opponent’s model aircraft cuts its
own streamer in flight or the
streamer, unless only string remains, becomes wrapped around the model
aircraft and/or the lines, the
heat shall be re-flown. |
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4.4.13. |
Conduct |
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a) |
A pilot must remain inside the centre circle while his model aircraft
is flying except at the moment of
release of his model aircraft by the pitman. |
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b) |
During the combat period each competitor (and his pit crew) shall be
watched by at least one member
of the F2D panel of judges specifically assigned to him, in addition to
the Circle Marshal, to ensure that
they behave in a fair manner according to the rules. |
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c) |
After a mid-air collision the heat shall continue as if both model
aircraft had landed, subject to articles
4.4.15.c), e), k), l), and m). |
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4.4.14. |
Offences
The following are warnable offences and shall attract the appropriate
penalties (4.4.11.g): |
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a) |
if a pilot unintentionally leaves the centre circle while his model
aircraft is airborne; |
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b) |
if the mechanics enter the flying circle at an oblique angle or cut
across the flying circle to reach a
downed model aircraft. One penalty only will be incurred for each offence
even if more than one
mechanic is involved; |
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c) |
if the mechanic(s)/pilot do not immediately, or after a line
disentanglement, withdraw a grounded
model aircraft to outside the 20 metre circle prior to servicing it; |
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d) |
if the model aircraft is launched prior to the starting signal; |
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e) |
if the mechanic(s)/pilot allows both engines to be running at the same
time during the 4 minute flight
period; brief bursts, not longer than 10 seconds to warm the engine with a
prime or to clear a flood is
permitted. Running the engine from the tank is not permitted. |
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f) |
1) If the silencer falls off during the flight or ceases to operate,
the pilot must land immediately and
replace the silencer, 100 points penalty.
2) If, as a result of a mid-air collision, the silencer is detached and
the model aircraft remains airborne,
the heat may continue but the silencer must be replaced on landing before
the model aircraft can be
used again. |
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4.4.15. |
Cancellation of the Flight
An entrant will be eliminated from the heat and his opponent declared the
winner, subject to 4.4.12.c), if: |
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a) |
he deliberately attacks the streamer of his opponent's model aircraft
prior to the Circle Marshal's signal
to commence; |
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b) |
his model aircraft fails to become airborne within two minutes of the
signal to launch; |
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c) |
he attempts to fly a model aircraft which at the time of launch does
not have a strong effective control
mechanism, or does not have a secure engine attachment or does not have a
running engine; |
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d) |
he interferes with his opponent, or forces his opponent to leave the
centre circle; |
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e) |
he leaves the lines or any of his model aircraft, which at that moment
are not airborne, in the centre
circle; |
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f) |
he attacks his opponent's streamer without his own, or the remaining
parts, attached to his model
aircraft; |
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g) |
he is not present at his allotted flight time, unless he has the
express permission of the Circle Marshal; |
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h) |
he leaves the centre circle, intentionally while his model aircraft is
flying, or without informing his
opponent of his intention to do so when his model aircraft is grounded for
a purpose other than to pick
up the lines of the reserve model aircraft or to allow his model aircraft
to be serviced; |
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i) |
he or any of his mechanics does not wear a protective helmet; |
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j) |
he flies in such a manner as to inhibit his opponent, or his opponent's
pit crew, from clearing any line
entanglement; |
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k) |
he flies other than level in an anticlockwise direction when only his
model aircraft is airborne and there
is no line entanglement; |
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l) |
he fails to clear any line tangle prior to launching his reserve model
aircraft unless both he and his
opponent have informed the Circle Marshal that they have agreed to
continue the heat without
clearing the line tangle. In this event the Circle Marshal must agree to
the continuation, only doing so
when he is satisfied that it is safe to continue; |
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m) |
for any other flagrant breach of the rules; |
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n) |
he releases the handle, or removes the safety strap, for any reason,
while the model aircraft is flying; |
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o) |
his model aircraft(s) does (do) not conform to para. 4.4.5.; |
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p) |
he interferes to cause a ground hit of, or collides with his opponent's
model aircraft that clearly has no
streamer left and flies level in anticlockwise direction without any
manoeuvres to chase and attack; |
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q) |
if the streamer becomes detached from the streamer retaining device
during combat, but not as a
result of the mid air collision; |
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r) |
if the model aircraft lands with no streamer string and the streamer
retaining device is missing or bent,
but not as a result of a mid-air collision; |
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s) |
if the mechanics jump over the opponent's model aircraft(s) and lines
kept within the pitting area; |
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t) |
if the pilot fails to land (subject to 4.4.14f); |
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u) |
the pilot's aircraft takes off without a complete and operating
silencer; |
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v) |
if a mechanic carries a model aircraft and lines over an opponent’s pit
crew he will be disqualified; |
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w) |
if one or both opponents are guilty of either:
a) causing line tangles; or
b) a “sawing” action on the line(s)
he or they may be disqualified at the discretion of the Circle Marshal. |
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x) |
if, during a line tangle where one or more models remain airborne, his mechanic(s) enters the flying
circle without explicit permission of the Circle Marshall. |
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4.4.16 |
Classification |
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a) |
The contest shall be run as a knockout tournament. |
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b) |
The competitor who obtains the highest score in points shall be the
winner of each heat. |
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c) |
A competitor shall be eliminated from the competition when he has lost
two heats. |
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d) |
Each round shall be randomly drawn (subject to 4.4.16.j)) from the
competitors remaining in the
competition. |
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e) |
In the event of an unmatched competitor remaining in any round, that
competitor shall be matched
with the first competitor drawn (subject to 4.4.16.j)) in the next round
and if he is not first eliminated in
each successive round, unless such time as there is again an unmatched
competitor remaining in a
round. At that time these two competitors shall be matched (subject to
4.4.16.j)) to complete that
round. |
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f) |
Individual and team standings will be based on the number of heats won.
Losses will not be
subtracted. |
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g) |
In the event of a tie for second or third place (both cannot happen)
fly them off using the above
procedures except allowing only one loss during the fly-off. |
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h) |
In the event of a two way tie for third remaining after a fly-off for
second, match them with the winner to
take third. |
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i) |
In the event of a tie score in any heat, that heat shall be re-flown. A
heat is considered a tie if the score
difference is 5 points or less. |
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j) |
Previous opponents and competitors of the same nationality shall be
drawn apart if possible with
competitors of the same nationality to fly against each other only if
there are no remaining opponents.
Defending champions, not members of their national team, are considered as
individuals not
possessing any specific nationality. |
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k) |
A specific junior final tournament will be organised if juniors are at
the same placing (tie) in the general
tournament, in order to define who is first, second and third for the
specific individual placing and will
have no influence on the general individual placing (no change in the team
classification). |
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4.4.17. |
International Team Classification |
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a) |
Each competitor shall be ranked according to his number of wins, not
counting fly-off heats, with the
fly-off heats being used to establish second and third place as necessary. |
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b) |
The competitors "win" scores, not counting fly-offs, shall be added for
the participants of each nation. |
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c) |
The team classification is established by taking the total scores,
obtained in 4.4.17.b) above, of the
three best scoring members of the team together. In the 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. Complete three-competitor teams are ranked ahead of
two-competitor teams which, in turn,
are ranked ahead of single competitor entries. |
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4.4.18. |
Judges and Timekeepers
The organisers shall appoint a panel of three judges who shall be selected
from a list of persons
proposed by National Airsport Controls for their proficiency and
experience and approved by the CIAM.
The judges must have at least one language in common. At World and
Continental Championships and
other limited entry international competitions the judges must be of
different nationalities. In open
international competitions the judges must be of at least two
nationalities and only two of them must be
approved by CIAM. Three timekeepers/scorers, efficiently briefed about
their task and trained on the field
during the practice flights, shall be allotted to each competitor for
World and Continental Championships,
two for open internationals. They are only responsible for the
competitor's score. If required, they can ask
the advice of the judge/circle marshal. |