NLH: Nominal Launch Height

Nominal Launch Height (NLH):

Starting an F5K plane is very similar to starting an F3K DLG plane. Launches are sort and spectacular. Difference is the speed which is applied during start and end of the launch. At F3K the start speed is very high (leaving hand) and the end speed is low (flying speed DLG). At F5K the start speed is low (leaving hand with motor on) and the end speed is high. Every second the plane flies, the speed is increasing. Result is an additional “zoom” height after the stop of the motor due to the “kinetic energy”.  

The motor stop is arranged by two parameters: the “Nominal Launch Height”and the “Motor time”. Both parameters can be set in an altitude device such as an Altis Nano from Aerobtec. Both height as motor time are announced by the Contest Director.

Please find all information about the Altis Nano device on their website: https://aerobtec.com/altis-nano/

 

Settings Altis – Nominal Launch Height (NLH) and Motor time:

Wind Forecast

Between [ m/s]

Nominal Launch Height (NLH) in ALTIS

Motor time [sec]

in ALTIS

Light breeze

0

3

60

7

Moderate wind

4

6

70

8

Strong wind

7

9

80

9

The wind forecast site from Windfinder will be used to define the expected average wind speed during the contest day. All details can be found on their website https://www.windfinder.com/

One (1) day before the beginning of the contest the Contest Director (CD) will announce the nominal launch height for the contest day. For this he will take the average windspeed between 11h and 17h. Some examples:

Windspeed 11h: 4 m/s 

Windspeed 14h: 2 m/s 

Windspeed 17h: 2 m/s 

Average speed: 2,7 m/s 

 Nominal launch height: 60 mtr

Windspeed 11h: 7 m/s 

Windspeed 14h: 8 m/s 

Windspeed 17h: 6 m/s 

Average speed: 7 m/s 

 Nominal launch height: 80 mtr

The CD may decide to change the nominal launch height in the event that the actual wind speed is very different compared to the expected wind speed.

Altis settings:

The Altis Altimeter can be programmed with the free Aerobtec software called “Flightmanager” . Please find all information on their website, https://aerobtec.com/altis-flight-manager/. For F5K you need to download version V4.4.0, which is released on the 20th  September 2019.

Altis – Logging settings:

Altis – Competition settings:

The next tab is the most important: Competition settings:

In this menu you have to program the Nominal Launch Height. In this example the NLH is 60 meter and the Time Switch is set on 7 seconds. Select “Altitude switch and F5K”.With these settings, the Altis is automatically reset in case the height is below 8 mtr. This setting is important as we fly multiple starts during one F5K task. Also select “Time switch” and set it to 7 seconds.

Select the “F5K height”button. Enter the maximum number of starts for which the Altis Nano should capture the height. During the F5K contest the maximum number of starts is 4. The Altis Nano will capture 4 launches. It is possible to have more than 4 starts, but this launch height will not be captured. Save this settings and push the “Back” button.

In the tab “Other” you can program the Screen type. Select “F5K”at the Screen type.

In the last Tab “Finish” you can save the settings:

Penalty and bonus rules during launch: 

As described before the Nominal Launch Height and motor time settings are saved in the Altis beforethe contest. During launch a penalty or bonus rule applies. No penalty applies in the event the zoom after motor stop is equal or less than 2 meter related to the Nominal Launch Height.

In the event the zoom is more than 2 meter and less than 6 meter a penaltyof 1 point per meter will be applied. If the zoom is more than 6 meter a penalty of 2 points per meter will be applied. All counted from the nominal launch height.

In the event the height is less than the Nominal Launch Height a launch bonusis applied. In the event the launch height is less than 2 meter and less than 6 meter a bonus of 1 point per meter will be applied. If the launch is less than 6 meter a bonus of 2 points per meter will be applied. All counted from the nominal launch height. You can find all details below in the “Nominal Launch Table”.

Penalty examples with different launch heights:

The Contest Director announced a nominal launch height of 60 mtr, PENALTYrules:

No launch penalty for heights           : 61 (0 points) and 62 (0 points)

1 point per meter penalty                   : 63 (-3 penalty), 64 (-4 penalty), 65 (-5 penalty), 66 (-6 penalty)

2 point per meter penalty                   : 67 (-14 penalty), 68 (-16 penalty), 69 (-18 penalty), 69 (-19 penalty), etc

The Contest Director announced a nominal launch height of 60 mtr, BONUSrulse:

No bonus penalty for heights            : 59 (0 points) and 58 (0 points)

1 point per meter penalty                   : 57 (-3 bonus), 56 (-4bonus), 55 (-5 bonus), 54 (-6 bonus)

2 point per meter penalty                   : 53 (14 bonus), 52 (16bonus), 51 (18 penalty), 51 (18 penalty), etc

For the NLH 70 and 80 meter the same penalty range / bonus is applicable (see table)

The launch altitude is recorded and captured in the Altitude device (Altis). After the task, the different launch altitudes are shown on the display. The pilot only has to put his launch scores on the score card. The Competition software counts the penalty or bonus points in the task score.

Be aware the launch height is measured during the 10 seconds after you have switched off the motor. The highest altitude is captured. In this example 66 mtr. This altitude was at the end of the zoom phase. The launch penalty for this example is -6 points.

Another examples, which shows that it is important to control your zoom altitude to avoid launch penalties.

Author: Brian van der Gouw