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F2D News Ė 6 March 2004
Mark Rudner
rudner@mit.edu

Well I donít know about you, but Iím sure ready to start hitting the circle pretty hard as soon as the weather allows it. This winter stuff has gone on long enough, and if the frequency of sunny days is any indication, the time for flying is just about here. In light of this, Iíll devote this monthís column to actually flying combat. So far Iíve discussed a bit about general rules, getting equipment, preparing that equipment, and trimming models. Once thatís taken care of, thereís only one thing left to do Ė tie some streamers on and have at it. Since most readers are primarily familiar with GX combat, Iíll try to compare and contrast the typical FAI match procedure and scoring with that of Formula GX. For those of you who are not familiar with Formula GX, just ignore the ďcompareĒ and stick to the ďcontrast.Ē

Match Procedure

Possibly the biggest difference between FAI combat and GX combat in terms of match preparation is that in FAI combat, each pilot is allowed to bring two models to every match (you still only fly one at a time). Itís not just two models either, itís two models, ready to go with engines mounted, bladders filled, each with its own set of lines, handle, everything. If the first model comes down for any reason, the spare can be started and launched fairly quickly to keep the action going.

Each pilot always takes two mechanics with him out to the circle. In contrast to GX combat, pitting often plays a major role in the unfolding of an FAI combat match. When a pilot and his mechanics arrive at the circle for the match, theyíll set the two models down (one in front of the other) outside the outer line of the circle marked on the grass, with both sets of lines pointing straight in towards the pilotís circle. Itís important to remember where you set your handles down, because if you need to switch to your spare model at some point during the match you wonít want to be searching around in the grass for your handle. One model, the ďprimaryĒ model, will be the one launched at the start of the match. The other model will serve as the spare.

See the figure below for a typical pre-match layout.

Notice that the two teams are separated by more than 90 degrees, and that each modelís inboard wingtip is outside the pitting circle marked on the ground. Leaving parts of the model sticking into the circle will land you with a 40 point penalty, so itís important to pay attention to where you are on the ground. The reason for this rule is safety Ė itís just not safe to be working on downed models underneath another model thatís still flying.

Once both pilots have arrived at the circle and have been handed their streamers, the circle marshal will start the one minute warm up period, often called the ďminute to the minuteĒ. This minute is vestigial in origin, dating back to when most combat engines were diesels. Itís a good time to check that all of your bolts are tight and that your bladders are topped off.

At the end of the warm-up minute, the circle marshal will call ďone minute to launch.Ē You may start your engine any time after a minute to launch has been called, but may not launch until the launch signal is given. Unlike in GX combat, in FAI combat one airtime point is awarded every second that one of your models is airborne starting from the moment that the launch signal is given by the circle marshal. One point is subtracted for every second that youíre not in the air. As a result, itís imperative that your mechanics get your engine started during the one minute long starting period so that you will be able to take-off on time. Fortunately, one minute is usually plenty of time to get the engine running and needled before it is time to launch.

One thing that I should mention at this point is that although it is okay to run the spare engine during the one minute starting period, after the launch signal is given each team may only have one engine running at any instant. The most that is allowed is up to a 10 second burst of the spare engine to burn out a prime Ė it may not be run from the tank. In the event of a crash, one of the mechanics must start the engine on the spare model (by hand), while the other mechanic runs over to the downed model to recover the streamer and transfer it to the spare.

Just as in GX combat, both pilots must fly level from the time of launch until the signal to begin combat has been given. The circle marshal will wait to give the combat signal until the models are separated by approximately 180 degrees so that neither pilot starts off from an advantageous position.

Each team is given only one streamer; in the event of a crash, one mechanic must recover the crashed model and transfer the streamer to the spare model while the other mechanic starts the engine on the spare model. Thus you need to equip your models with a secure quick-release mechanism for attaching/detaching the streamer. The drawing below shows the most common streamer-attaching system.

This is a two-piece system, with a metal hook that attaches to the top of the model using one of the engine mounting bolts, and a soldered metal ring that snaps securely into the hook. The streamer string is tied directly to the metal ring. In the event of a crash, the mechanic simply pulls the metal ring out of the hook on the crashed model and runs over to snap it back on to the hook of the spare model. Each model has its own hook, but the ring/streamer is shared between them. You will be penalized if your streamer attaching system fails by itself in the air causing the streamer to fall off without being cut, so itís pretty important to put some thought into your streamer attaching system.

Although it might seem harsh that there are many ways to be penalized in FAI combat, the rules are there just to ensure safety and fair-play for all competitors. In the case of the streamer hook, without a penalty one could just invent a system to dump the streamer off 15 seconds into the match, and his opponent would never be able to cut him.

The flight period of an FAI combat match is 4 minutes, counted from the moment that the launch signal is given. Regardless of what happens (mid-airs, crashes, etc), the timing continues uninterrupted from the launch signal until the 4 minute match period expires.

Scoring Summary

Hereís a quick run-down on the scoring of an FAI match. Please see the official rules (available on the webpage) for a full listing.

These were all good questions, and I hope that they have answered some concerns for more than just those individuals who asked them. If you have other questions, please donít hesitate to contact me so that I can address them in future columns. Happy flying!

Airtime: +1 point for every second airborne, -1 point for every second not airborne

Cuts: +100 points for each cut of the crepe paper streamer. 0 points for a cut consisting of string alone (but a cut of the string to which there is still paper attached does count)

Penalties: -40 points for a) pilot unintentionally stepping outside of the pilot circle while flying, b) mechanics servicing a model inside the pitting safety line, c) mechanics leaving a downed model inside the pitting circle. -100 points for damaging the streamer during a pitstop; additionally, a new streamer must be obtained from the judges to continue the match. Disqualification will result if a) after a crash, a pilot leaves his handle or any part of his lines inside the pilotís circle, b) the mechanics jump over or cut through the equipment of their opponents, c) the pilot intentionally steps out of the pilotís circle to avoid being cut or to gain an advantage over his opponent, d) pretty much any type of blatantly unsafe or unsportsmanlike conduct.

Let me comment briefly about two of the disqualifiable offences. First, after a crash takes place, the pilot whose model has come down must clear all parts of this lines/handle from the pilot circle. After doing so, he may then walk over to pick up the handle/lines attached to the spare model. This is a very simple rule to follow, and should never be forgotten. If you leave lines inside the pilotís circle (Iíve seen this happen), you or your opponent may become tangled up in them which could result in a very big mess. Additionally, when you set your lines down outside the pilotís circle, you must be careful not to lay them down across your opponentís spare lines Ė if he needs to use his spare model and your lines are laying on top of his, he will not be able to take off and you will be held responsible for it by means of a disqualification. Again, these rules are entirely about safety and fair-play.

Last, a few words about pitting. The rule is that the mechanics may not jump over or cut through the equipment of their opponents. The mechanic who is running to recover a downed model may go around the outside of his opponentís pit, but may not cut through it. On the other hand, the mechanic holding the spare model may not carry the model over the opponentís pit, even if he walks around the outside of them. If he wishes to move to a different location, he must walk around the circle in the direction that does not take him through the opponentís pit.

Hopefully this gives you a good heads-up about the specifics of how an FAI combat match is run. Itís a lot of stuff to think about, but weíll have plenty of time to discuss it and to get familiar with these rules. Neil has scheduled a few FAI practice sessions, at which we can all get together and try out our new equipment and get a feeling for how all of this stuff goes. If you have any questions, please let me know. I think it would be great if I could do a Q&A column next month answering specific questions that people have. Be assured Ė if thereís something youíre unclear about, there are undoubtedly many others who feel the same way. Having been exposed to this event from the very beginning of my flying career, sometimes itís hard for me to know what issues people may find confusing or weird. See yíall soon!


If you have any questions or comments, please email Mark at rudner@mit.edu