Editing Model aircraft (section)

==Competitions and classes==
World competitions are organized by the [[Fédération Aéronautique Internationale]] (FAI) in many classes, groups, and subclasses:
*Class F – model aircraft
**F1''x'' – [[#Free flight (F1)|Free Flight]]
**F2''x'' – [[#Control line (F2)|Control Line]]
**F3''x'' – [[#Radio-controlled flight (F3)|Radio Control]]
**F4''x'' – [[#Scale aircraft (F4)|Scale Aircraft]] (a reduced-size reproduction of a full-size aircraft)
**F5''x'' – [[#Radio-controlled electric motor gliders (F5)|Radio Control Electric Powered Motor Gliders]]
**FAI – Drone Racing (F3U)
*Class S – space model
*Class U – unmanned aerial vehicle

===Free flight (F1)===
The Wakefield Gold Challenge Cup is an international modelling competition named for the donor, [[Charles Wakefield, 1st Viscount Wakefield|Lord Wakefield]]. The event was first held on 5 July 1911 at [[The Crystal Palace]] in England. There were contests in 1912, 1913 and 1914. No contests were held again until 1927, when the [[British Model Flying Association|Society of Model Aeronautical Engineers]] (SMAE) approached Lord Wakefield for a new larger silver trophy for international competition. This trophy is the present Wakefield International Cup and was first awarded in 1928. The SMAE organized the international competitions until 1951 when the [[Fédération Aéronautique Internationale|FAI]] took over, and has since been made the award for the rubber-power category at the FAI World Free Flight Championships.
The FAI free flight classes include:<ref>{{Cite web |url=https://www.fai.org/sites/default/files/sc4_vol_f1_freeflight_24_final.pdf |title=FAI Sporting Code - Free Flight Model Aircraft 2024 Edition |author=<!--Not stated--> |date=1 January 2024 |publisher=[[Fédération Aéronautique Internationale]] |access-date=30 November 2024}}</ref>
*F1A – Gliders
*F1B – Model Aircraft with extensible (rubber band) motors – Wakefield Trophy
*F1C – Power model aircraft (combustion powered {{cvt|2.5|cc|cuin}})
*F1D – Indoor model aircraft
*F1E – Gliders with automatic steering
*F1N – Indoor hand-launch gliders
*F1P – Power model aircraft (combustion powered 1.0cc)
*F1Q – Electric power model aircraft
*F1G – Model aircraft with extensible (rubber band) motors « Coupe d’hiver » (provisional)
*F1H – Gliders (provisional)
*F1J – Power model aircraft (provisional) (combustion powered {{cvt|1.0|cc|cuin}})
*F1K – Model aircraft with {{CO2}} motors (provisional)
*F1L – Indoor zone EZB model aircraft (provisional)
*F1M – Indoor model aircraft (provisional)
*F1R – Indoor model aircraft “Micro 35” (provisional)
*F1S – Small electric power model aircraft “E36”

===Control line (F2)===
{{Main|Control line}}
[[File:F2C flying models.jpg|thumb|F2C class control line models]]
Also referred to as U-Control in the US, it was pioneered by the late Jim Walker who often, for show, flew three models at a time. Normally the model is flown in a circle and controlled by a pilot in the center holding a handle connected to two thin steel wires. The wires connect through the inboard wing tip of the plane to a mechanism that translates the handle movement to the aircraft elevator, allowing maneuvers to be performed along the aircraft pitch axis. The pilot turns to follow the model going round, the convention being counterclockwise for upright level flight.

For the conventional control-line system, tension in the lines is required to provide control. Line tension is maintained largely by [[centrifugal force]]. To increase line tension, models may be built or adjusted in various ways. Rudder offset and [[thrust vectoring]] (tilting the engine toward the outside) yaw the model outward. The position where the lines exit the wing can compensate for the tendency of the aerodynamic drag of the lines to yaw the model inboard. Weight on the outside wing, an inside wing that is longer or has more lift than the outside wing (or even no outside wing at all) and the torque of a left rotating propeller (or flying clockwise) tend to roll the model toward the outside. Wing tip weights, propeller torque, and thrust vectoring are more effective when the model is going slowly, while rudder offset and other aerodynamic effects have more influence on a fast moving model.

Since its introduction, control line flying has developed into a competition sport. There are contest categories for control line models, including Speed, Aerobatics (AKA Stunt), Racing, Navy Carrier, Balloon Bust, Scale, and Combat. There are variations on the basic events, including divisions by engine size and type, skill categories, and age of model design.

The events originated largely in the United States, and were later adapted for use internationally. The rules for US Competition are available from the Academy of Model Aeronautics. The international rules are defined by the Fédération Aéronautique Internationale (FAI). World Championships are held semiannually throughout the world, most recently in 2008 in France, with a limited slate of events – special varieties of Racing (F2C or "Team Race"), combat (F2D), and speed (F2A), all limited to engines displacing 0.15 cu. in (2.5cc), and Stunt (F2b), which is essentially unlimited with regard to design and size.

CIAM (FAI Aeromodelling Commission) designated the following classes in the F2 Control Line category:<ref>{{Cite web |url=https://www.fai.org/sites/default/files/sc4_vol_f3_aerobatics_23.pdf |title=FAI Sporting Code - Radio Control Aerobatics 2023 Edition |author=<!--Not stated--> |date=1 January 2023 |publisher=[[Fédération Aéronautique Internationale]] |access-date=30 November 2024}}</ref>

;F2A : CL Speed
;F2B : CL Aerobatics
;F2C : CL Team racing
The international class of racing is referred to as F2C (F2 = Control-line, C=racing) or Team Race. A pilot and a mechanic compete as a team to fly small {{cvt|370|g|oz}} {{cvt|65|cm}} [[wingspan]] semi-scale racing models over a tarmac or concrete surface. Lines are {{cvt|15.92|m}} long.

Three pilots, plus mechanic teams, compete simultaneously in the same circle, and the object is to finish the determined course as fast as possible. Tank size is limited to {{cvt|7|cc|cuin}}, requiring 2 or 3 refueling  pitstops during the race.

The mechanic stands at a pit area outside the marked flight circle. The engine is started and the model released on the start signal. For refueling, the pilot operates a fuel shutoff by a quick down elevator movement after the planned number of laps so that the model can approach the mechanic at optimum speed, of around {{cvt|50|km/h|order=flip}}. The mechanic catches the model by the wing, fill the tank from a pressurized can by a hose and finger valve, then restart the engine by flicking the propeller with his finger. A pitstop generally takes less than three seconds.

The course is {{cvt|10|km|order=flip}}, with 100 laps. Flying speeds are around {{cvt|200|km/h}}, which means that the pilots turn one lap in roughly 1.8 seconds. Line pull due to centrifugal force is {{cvt|85|N|lbf|order=flip}}. An overtaking model is steered over the heads of the competing pilots of slower models.

After two rounds of elimination heats, the 6, 9 or 12 fastest teams enter two semifinal rounds, and the three fastest teams in the semifinals go to the final, which is run over the double course. Single cylinder two-stroke [[Diesel engine|Diesel compression ignition engines]] designed for this purpose of up to {{cvt|2.5|cc|cuin}} are used. At the world championship level it is common for competitors design and build their own engines. Output power approaches {{cvt|0.8|hp}} at 25,000 rpm.

====F2D – control line combat====
CLASS F2D -  Control Line Combat Model Aircraft - Two pilots compete, with four mechanics in the pit. The aircraft are light and stubby so as to maneuver quickly in the air. Each has a {{cvt|2.5|m|order=flip}} crepe paper streamer attached to the rear of the aircraft by a {{cvt|3|m}} string. Each pilot attacks only the other aircraft's streamer, to attempt to cut it with their propeller or wing. Each cut scores 100 points. Each second the model is in the air scores a point and the match runs for 4 minutes from the starter's signal. At the almost {{cvt|200|km/h|order=flip}} speeds of the aircraft, mistakes often lead to crash damage so two aircraft are permitted for each match. The mechanics are prepared for crashes and quickly start the second aircraft and transfer the streamer to the reserve model before launching. The action is so fast that an observer may miss the cuts of the streamers. A second loss eliminates a competitor, and the last pilot still flying wins.<ref>{{cite web |title=F2 - Control Line |url=https://www.fai.org/page/f2-control-line |publisher=FAI Aeromodelling Commission (CIAM)}}</ref>

===Radio-controlled flight (F3)===
The FAI radio control classes include:<ref>{{Cite web |url=https://www.fai.org/sites/default/files/sc4_vol_f3_aerobatics_23.pdf |title=FAI Sporting Code - Radio Control Aerobatics 2023 Edition |author=<!--Not stated--> |date=1 January 2023 |publisher=[[Fédération Aéronautique Internationale]] |access-date=30 November 2024}}</ref><ref>{{Cite web |url=https://www.fai.org/sites/default/files/sc4_vol_f3_aerobatics_23.pdf |title=FAI Sporting Code - Radio Control Soaring Model Aircraft 2021 Edition |author=<!--Not stated--> |date=1 January 2021 |publisher=[[Fédération Aéronautique Internationale]] |access-date=30 November 2024}}</ref>
;F3A : RC Aerobatic Aircraft
;F3B : RC Multi-Task Gliders
;F3C : RC Aerobatic Helicopters
;F3D : RC Pylon Racing Aeroplanes – Pylon racing refers to a class of air racing for radio controlled model aircraft that fly through a course of pylons.<ref>{{cite web |title=National Miniature Pylon Racing|url=http://www.nmpra.net/|website=nmpra.net|publisher=NMPRA|access-date=6 July 2015}}</ref> The sport is similar to the full-scale Red Bull Air Race World Series.
;F3F : RC Slope Soaring Gliders
;F3J : RC Thermal Duration Gliders
;F3K : RC Hand Launch Gliders
;F3M : RC Large Aerobatic Aircraft
;F3N : RC Freestyle Aerobatic Helicopters
;F3P : RC Indoor Aerobatic Aircraft
;F3H : RC Soaring Cross Country Gliders
;F3Q : RC Aero-Tow Gliders
;F3R : RC Pylon Racing Limited Technology Aeroplanes
;F3S : RC Jet Aerobatic Aircraft
;F3T : RC Semi-Scale Pylon Racing with Controlled Technology Aeroplanes
;F3U : RC Multi-rotor FPV Racing – The FAI Drone Racing World Cup is in the F3U class (Radio Control Multi-rotor FPV Racing). This is a highly competitive [[drone racing]] activity, involving mental exertion and big cash prizes.

=== Scale aircraft (F4)===
The FAI classes for scale model aircraft (a reduced-size reproduction of a full-size aircraft) include:<ref>{{Cite web |url=https://www.fai.org/sites/default/files/sc4_vol_f4_scale_24.pdf |title=FAI Sporting Code - Flying Scale Model Aircraft 2024 Edition | author=<!--Not stated--> |date=1 January 2024 |publisher=[[Fédération Aéronautique Internationale]] |access-date=30 November 2024}}</ref>
;F4B : control line scale aeroplanes 
;F4C : radio control scale aeroplanes 
;F4H : radio control stand-off scale aeroplanes

=== Radio-controlled electric motor gliders (F5)===
The FAI classes include:<ref>{{Cite web |url=https://www.fai.org/sites/default/files/documents/sc4_vol_f5_electric_21.pdf |title=FAI Sporting Code - Radio Control Electric Powered Motor Gliders |author=<!--Not stated--> |date=1 January 2021 |publisher=[[Fédération Aéronautique Internationale]] |access-date=30 November 2024}}</ref>
**F5B – Electric Motor Glider – Multi Task (held in alternate years only)
**F5D – Electric Pylon Racing
**F5J – Electric Motor Glider – Thermal Duration