Competition Ballooning – Land Run

The rule (or information) for this task is set out in Chapter 15 of the Event Rules

The idea of this task is to fly in one direction making point A at the start of that first leg and point B at the end and then make a change in direction from that first leg such that the third point at the end of this second leg creates a triangle with the largest area possible. The area made depends on how the 3 points are determined. In some LRN tasks you are given a circle on the map as the area within which the three points have to be. To make the perfect LRN in this situation you need a change in wind direction with height of over 120o. Point A is when you enter the circle and point C is when you leave it. You then have to fly within that circle such that point B creates an equilateral triangle and with that you will have created the largest area within that circle (figure 1). Sometimes you are given the centre point of the circle on the task sheet and sometimes you have to declare your own centre point. cIn both situations you have to enter the circle such that it gives you the best angle within that circle. This requires pre-planning and knowledge of the wind directions with height which hopefully you will have been given in the met briefing. Possibly the best way of approaching this is to work out the best angle you will achieve with the wind conditions. As in the example (figure 1), if the wind on the ground is heading roughly due north and that at 4000’ comes round to a direction of 1500 degrees you need to enter somewhere on the southwest border of the circle. This is now where you have to have to be clever in maths to solve the equation – I am not! The sides of an equilateral triangle within a circle of 3km is 5.19km (Google it!!). You then draw your 5.19km line to where it touches the top of the circle and you aim for that. Remember the turn. In this task if you leave the circle you have finished the task. After declaring point B you then head down to point C which should be where the next 5.19km line hits the circle. This task is rarely set with markers as a means of scoring; it is now almost always done with electronic scoring. This may be where you only have a simple logger and point A and point C is where you enter and leave the circle and point B will be determined by the scorers as giving you the best area. In the new FAI loggers you may have to press the logger button to indicate point B and sometimes you may also have to do the same to indicate points A and C. It is very cruel if you produce a perfect equilateral triangle and end up forgetting to press the logger at point C before you leave the area!

Figure 1: Example of a LRN with a circle as the scoring area

In some LRNs you are not given an area but a time to complete it within; commonly 30 minutes. Point A may be your last marker drop or a point you decide yourself on the logger. The largest area you will make in this situation is to fly both legs of equal time i.e. 15 minutes each in this example. Where you need a mathematical degree is calculating whether to go for speed or change in direction. If you look at the next example (Figure 2) you will see that after the first leg A-B you have the choice to fly at two different heights; one gives you a greater change in direction but less speed than the second. The balloon following the blue path to point C1 is travelling in a direction of 0490 at 3kts. By going higher (balloon taking the red path) you achieve a direction of 0170 at 8kts. In this situation the blue pilot achieves 1.62km2 whereas the red pilot achieves 2.1km2. The faster (red) pilot does better. However if the red pilot had only reached a speed of 7kts in a direction of 0170 he/she would have only made 1.5km2 and the slower blue pilot would have been better. As I am not a mathematician you can understand why I am not very keen on this task!

Figure 2: A LRN with a set time

However this task can be rewarding if there are good predictable wind velocities that allow you to calculate the best area you can achieve. It has also produced some interesting results as well. In the European Championships in Belfort in 1992 when it was set for the first time Point B was set as a grid reference on the map. Point A was something like your take off point and B your landing point. By flying past point B as far away as possible gave you the LRN area though you were only flying in a straight line. There was a prior task that evening with certain take off parameters so most pilots took off south west of point B to comply with this and flew easterly to the edge of the scoring area. Uwe Schneider realised that within the rules one could ignore these take off parameters and chose the area north of point B which gave a longer flight. His ultimate area was vastly superior to everyone else’s except for one pilot. A Russian pilot had no idea how to fly this task so followed Uwe and took off with him. Seeing Uwe land he followed him in but misjudged the approach and landed one field further on and thus won the task!

Belfort 1992

Written by David Bareford