Frequent Questions
- Why F5J?
- What equipment do I need in my glider?
- How does the points scoring work?
- Is flight time measured by the altitude limiting device?
- Does the motor run time need to be logged?
- What is the F5J altitude?
- How long are the flights?
- How much power do I need?
- What does the altitude limiting device do?
- How many motor runs are allowed?
- Can one adjust the cut off altitude to below 200m on the Altis?
Why F5J?
If you are tired of carting around a heavy and expensive electric winch, or you cannot persuade your two tow-men to come fly with you, then you are ready for F5J.What equipment do I need in my glider?
- A suitable electric motor, brushed or brush-less, in-runner or out-runner.
- A folding prop to minimize drag once the motor shuts down.
- An electronic speed control (ESC) for the motor.
- An altitude limiting device.
How does the points scoring work?
The points system work by penalty for altitude. You get penalized 0.5 points per meter from ground level up to 200m after which you get penalized 3 points per meter.For example:
- You launch to 160m (160 x 0.5 = 80 points)
- You launch to 225m (200 x 0.5 = 100 + (25 x 3) = 175 points)
Is flight time measured by the altitude limiting device?
No, it is measured by stopwatch. From when the plane leaves your hand, to the time it touches the ground or any other grounded object.Does the motor run time need to be logged?
Motor run time is not logged, you get one motor run of maximum of 30 seconds, use it or lose it. The more powerful gliders will use maybe 10 or 15 seconds to reach altitude, but it gives them no real advantage.What is the F5J altitude?
To prevent zooming to a higher altitude using stored speed or kinetic energy, the F5J altitude is the maximum altitude attained from the time of launch, until 10 seconds after the motor is cut. In other words, if you have a hot-liner and cut the motor at 150m it might be possible to still reach 200m due to the high speed (kinetic energy). The altimeter will then record not the 150m where you cut the motor, but the higher altitude attained by coasting along. It might be possible to launch into a good thermal and attain over 200m, thus penalty points, but in reality you are still in control, as you can cut the motor early or fly level. The power to weight needs to be optimized to get to 200m within 30sec...so outright power ending up with a weight penalty is not optimal.How long are the flights?
Working time is 10 minutes (600 seconds). In F5J it is possible to fly the full 10 min. Time starts as the glider leaves your hand, and stops when you land. Fly-off rounds are 15 minutes.How much power do I need?
I fly a Tsotsi (2m wingspan weighing about 1100g) with a Park 480 (brushless) and it has more than enough grunt to get up to 200m in about 25 seconds. Some pilots have rocket like fully moulded carbon gliders that gets them there in about 10 seconds. (these rigs can be quite heavy). I work by trial and error (I know that is not very scientific) but 300 or 350watt should get a 1500g glider up there in the allotted time.What does the altitude limiting device do?
The altimeter device has 2 functions for strict F5J competition.- It limits the maximum motor run time to 30 seconds.
- It measures the highest attained altitude within a 10 second period after the motor is shut down either automatically (after 30 seconds) or manually by the pilot.
- Records altitude, temp, throttle position, battery voltage etc.
- Allows motor emergency on for practice purposes.
- Allows setting the motor cut-off altitude.
- Allows changing the motor cut-off time.
