If Thermal Duration and ALES contests are the plain vanilla formats for non-electric and electric R/C gliders respectively, then F3J and F5J can be considered their advanced counterparts. That is to say, both F3J and F5J contain elements that award extra points for demonstrating greater launching control (in F3J) and thermaling and flying skills (in both). While F3J has been around for many years F5J is still a relative newcomer in the US. With the still growing popularity of electric soaring worldwide the F5J contest format is destined to grow considerably over the next few years.

F5J – Thermal Duration Gliders with Electric Motor and Altimeter/Motor Run Timer

F5J is very similar to F3J as another man-on-man format but with electric powered models that are fitted with a special altimeter/motor run timer. Another fundamental difference is that F5J pilots are not organized into teams.

Qualifying and Fly-off rounds: An F5J contest consists of a minimum of 4 qualifying 10-minute rounds in which all pilots participate. As of the 2017 FAI rules the CD now has the option of having flyoffs, or not. If flyoffs are held then the top 30% of pilots are placed into a single group for 3 or 4 fly-off 15-minute rounds. Scores from qualifying rounds do not carry over to the fly-offs.

In both the qualifying and fly-off rounds flight durations must be performed within the working time limits (i.e. 10 or 15 mins) or a penalty will result. This means that pilots who launch at the very start of the working time and land closest to the end of the working time will have the highest duration scores. Note that the start time in F5J is the moment of release of the plane.

Launch height penalty:  In the F5J rules there is a height penalty based on “…the maximum altitude recorded from the moment the model leaves the launcher’s hand until 10 seconds after the motor is stopped.” This penalty deducts 0.5 points per meter for start heights up to 200 meters, and 3 points per meter for start heights above 200.  e.g. a start height of 201 meters would incur a height penalty of 103 points.

For a thorough explanation of F5J Start Height see this page.

After each flight the plane’s altimeter must be read and recorded by the scorekeeper. Same as with F3J, flight time points are computed at a rate of 1 point per second up to the working time period maximum.

Overfly penalty: in F5J if you overfly the working end time you lose all bonus landing points. Overflying past 1 minute gets you a zero flight score.

Landing:  Landing bonus points (50 maximum) are made by landing as close to a marked landing spot as possible. Scores are computed at a rate of 5 points per meter e.g. if the nose of the plane was between 3 and 2 meters away from the spot the score would be 40 points. Note that no landing bonus will be awarded if the plane’s duration exceeds the working time limit.

Scoring: An F5J task score is made up of:

  • One point per second of flight duration,
  • plus the F5J landing bonus (only awarded if the plane does not overfly the working time limit),
  • minus the height penalty.

There is no penalty for motor run time but there is a specified maximum motor run time of 30 seconds. The maximum duration score you can get on your stopwatch is 9:59:99 which is still a 9:59 score. If your scorekeeper writes down a 10:00:00 that means either a human stopwatch button press error or the announced flight time window is in error i.e. not exactly 10 mins long between the working time horns. As such it’s very important that the scoring announcement system is verified to give exactly 10 mins (or 15 mins for fly-offs) between the horns.

(updated 1-2-2017)

F5J Strategy Primer — The Basics

f5j-flightline-04In ALES competitions everyone launches and gets essentially the same height since there is no penalty for flying all the way up to the cutoff altitude. In F5J the higher you fly during the launch phase the greater you are penalized. So the biggest additional challenge (and source of extra points) of F5J compared to ALES is to try and find as low a thermal as possible before the launch period is over. As it turns out this single difference significantly changes the game from what often is a “landing contest” in ALES to a thermal skills competition in F5J.  i.e. you can gain far more extra points by choosing to cut your motor at a lower altitude than by nailing a landing.

As fundamental of a goal as lower launch heights may sound, aside from the obvious increased difficulty of working lower narrower thermals, in practice it can add several additional layers of challenge. First, it is not uncommon that an area of the field with known “thermal bubbles” will attract multiple planes during a given round’s launch. This means the area can become congested (video example). So use extra caution if you choose to enter such an area.

A related challenge has to do with the plane’s launch phase speed when performing low altitude thermal searches. Unlike ALES launches where you are essentially gunning your motor to get to maximum altitude as soon as possible, in F5J the optimum launch speed may in fact be much slower so as to enable better thermal detection. So on some flights you may be balancing launch speed with thermal search ability which can be highly plane and thermal-spotting-skills dependent.

Other differences in rules and how they might affect task strategy can be explored on the FAI rules page.

(updated 1-2-2017)

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