Editing Control line (section)

===Combat (F2D)===
[[File:CL Combat.jpg|thumb|Denmark versus Australia at the Danish Combat World Cup 2008]]
[[File:CL Combat Launch.jpg|thumb|Mechanics launch an F2D combat model]]
Combat is an event where two pilots "dogfight" for cuts on their opponent's streamer, for a perscribed amount of time called the "Match". Models are fast and highly maneuverable typically of flying-wing types, which chase each other around the sky at speeds in excess of {{convert|100|mi/h|km/h|abbr=on}}. Despite deliberate mid-airs being banned, the carnage rate is high, and pilots commonly bring 10 or more models to a competition.

In the US there are three A.M.A. Events, which are Fast Combat (up to a .36 c.i.d. engine is allowed), Speed Limit Combat and 1/2A (up to a .051 c.i.d. engine is allowed) Combat which can be flown high or low performance.  In any event where the model exceeds 75&nbsp;mph, the model must be equipped with a fuel shut-off, which shuts the engine off, when the control lines are cut. Combat may be held as a kill event, or a no-kill event.  A kill is scored when one competitor cuts the string that holds the streamer (of his opponent), to the plane, and is an instant win of the match. Cutting the streamer however results in an award of points.  In No-Kill combat cutting the string is the same as cutting the streamer and only points are awarded. There are a lot of unofficial events held throughout the US, such as Northwest 80&nbsp;mph Combat, WWII combat, Formula GX Combat, 15 Fast and the like.  Combat requires perhaps the fastest reflexes of any CL event, and pilots skilled at combat typically compete well in other events like Stunt or Racing.  Combat has been described as a team sport, with the pilot relying on up to a two-person pit crew. As may be imagined, with two pilots not cooperating with each other, line tangles can happen suddenly, and crash landings are common. Despite the high speed of the models, most combat models are made to be quite robust, and when time allows may hit the ground and suffer little damage and be relaunched.  Although for the Speed limit events up to a .40 c.i.d. engine may be used, for the AMA fast event, there is only one manufacture of a high performance .36, that being Henry Nelson.  A well-tuned and fueled Nelson 36 may achieve 25,000 r.p.m. while statically running on the ground and gain significant r.p.m. in the air.  Current 1/2A engines in use are all from former soviet republics and include the Fora and Cyclon, both of which will run well above 33,000 r.p.m.  In all the AMA events pressure fed fuel systems are allowed and virtually every combat plane is equipped with a fuel "Bladder".  The Fuel Bladder gives the most consistent fuel feed while the aircraft is undergoing sudden and violent maneuvers, typical of flying in a match.

'''F2D combat''' - the international class for combat - is most popular in Russia and Europe, where some countries have professional or semi-professional teams. Russia and the former Soviet countries are currently the main producers of world-class equipment for this sport, including engines. Their combination of the latest engineering and design, with exotic metallurgy and experience, results in combat engines which reliably turn 32,000 rpm, and can be restarted easily in the event of a crash. Requiring lightning-fast reflexes, combat has frequently been used as a training-ground and/or hobby for many commercial and military pilots {{citation needed|date=September 2020}}.