F5J has arrived !

After a lengthy and by some accounts a sometimes difficult consultation between representatives of the many interested countries via the web, a set of F.A.I.  rules were finally agreed a few weeks ago. This now internationally accepted set of rules is provisional for the next 12 months during which time it is expected some ‘fine tuning’ will be found necessary after a few comps are run.

As with our UK ‘height limited’ competitions, virtually any electric powered model glider is suitable, and all must be equipped with a micro ‘data logger’ which has to be fitted between the receiver and the esc., but that’s about the only similarity.

With UK ‘height limited’ rules (BARCS version or BMFA) the data logger cuts the motor after 30 seconds run time or when the model reaches 200 metres, whichever comes first. The data is available to download via a computer for checking after the event or if it is required by the competition CD. This has evolved into a popular event with several leagues now running and it is felt that the limit on height ‘levels the playing field’ for everyone.

The new international class is different in a number of respects, the most important being that there is no ‘limiter’ to cut the height you can launch too. But the rules have been written so that the 200 metre mark is still recognised as a launch limit for scoring purposes.

The aim of the class is to have a competition similar in most respects to F3J.  A slot is 10 minutes duration, but unlike F3J, flight time starts as soon as the model is launched.  No re launch is possible and apart from that it follows long established and similar rules for landing precision, overflying etc.

The data logger controls the motor run time, and it will allow you to run your motor for up to 30 seconds. You can use the full motor run time or cut off earlier, the choice is yours, but it will not stop the motor at any given height. It’s worth noting that you only get one chance of a scoring flight in each slot because once you start your motor and launch, the data logger will not allow the motor to be restarted until it has been reset, and this requires all power to be disconnected.

What the logger records is the height your model reaches 10seconds after you cut your motor run. Once your flight is finished, your time keeper will plug  a hand held ‘card reader’ into the logger which reads the stored  launch height data and this is recorded along with your flight time and landing bonus or penalty. The recorded launch height is vital to calculate your score and if you fail to record the figure you get a zero flight score.

Scoring works like this.
Half a point is deducted for every metre of height your model reaches on launch up to 200 metres. If you launch above 200 metres a penalty of 3 points per metre is deducted.
This all makes for a very challenging competition, which will be won by the pilot who launches low, has the longest flight time and has the highest landing bonus. Oh and just like F3J you don’t have a motor to get you back if you fly too far down wind.

Peter Mitchell.