by BomberWestern Soarers HG Club



    This article looks at some small things you can do that should increase your chances of getting to where you plan to.


   The first tip is to estimate how long it will take you to fly your chosen course. Given you know the thermal heights for the day, the strength of thermals and the wind speed (all can be calculated from a temp trace) the table below provides the average cross country speed at best L/D.


thermal strenght 
d km/h
  0 5 10 15 20 25 30
0.5 16 21 26 31 36 41 46
1 24 29 34 39 44 49 54
1.5 28 33 38 43 48 53 58
2 31 36 41 46 51 56 61
2.5 33 38 43 48 53 58 63
3 35 40 45 50 55 60 65
3.5 36 41 46 51 56 61 66
4 37 42 47 52 57 62 67
4.5 38 43 48 53 58 63 68
5 39 44 49 54 59 64 69


    Given you know your average Cross Country speed, you can work out how long the flight will take.

    Example: 2 m/s thermals to 2,300 m with 10 km/h tail winds. Average cross country speed is 41 km/h. If your flying a 160 Km course it should take about 4 hours.


    The second tip is knowing what time to take off. If you know how long the flight is going to take and what time thermals will start (this can also be calculated from the temp trace) you can figure out the best time to take off.

    Example: The flight above will take 4 hours and thermals will start at 10 am. The best part of the day is 2 pm till 4 pm. So we want to fly during this time and an hour either side. Therefore take off time is 1 pm with ETA at 5 pm. If you want to play safe you could take off early. However, it would be risky to wait till 2 pm and fly from 2 pm till 6 pm.


    Fly with a digital watch with an alarm. This seems a bit odd but apart from knowing what time it is you can do two useful things. The first is to set the watch to beep on the hour – this provides a prompt to think about the following:

• How far did I fly in the last hour?

• Is this the average speed I expected?

• Can I still get to goal at this speed?

    The second is to set your alarm for 2 hours before sunset (sunset times can be gained from your Garmin GPS). At about this time you should be thinking of getting as high as possible as it is nearing the time for the last good thermal of the day. To get to goal or extend your flight you want to be high at the end of the day and use the good air.


    When leaving the paddock in your first thermal note the angle that you are climbing away from the thermal source. This will provide you with a visual reference of how far down wind to fly of any thermal sources to find the thermal.


    Stay up wind of the course line. When you first start your flight you are fresh and unstressed. By the time you finish your flight (depending on the length) you can be tired, impatient, dehydrated and stressed. By being upwind of the course line you can afford to dribble downwind into goal when the lift gets weaker and your decision making is less efficient.

To plan to stay up wind of the course line you can do the following:

• Draw a straight line on your map between goal and take-off

• Figure out what the wind might do during the day (eg typical at Wylie an Easterly swings to a South Easterly)

• Plan to fly on the up wind of the course line (eg South of the course line). Check out the roads you might follow


    Check your stress levels in flight. As you become more stressed your brain shuts out external stimuli. If this occurs you might not notice those clues that often provide indications of lift. To check your stress levels try the following:

• Each hour (or more often) check your grip on the base bar – if your knuckles are white your holding on too tight

• Check the level of fatigue in your shoulder or legs from pushing out in the harness

• To relax look around you and enjoy the view. The best way to stay relaxed is to realise when you’re not.


    Know roughly how far from goal you can glide in from. This is simple if you have a final glide table (available on the club web site). During the flight you know what height thermals are going to. If you have a GPS and wind speed indicator then the difference in reading represents the wind speed at a given altitude. Knowing this allows you to calculate how far from goal you need to be to glide in. This can be done way before you get to goal.


L/D   25.26 22.45 19.65 16.88 14.15 11.49 8.93 6.57 4.56  
  0.935 0.94 0.945 0.955 0.975 1.005 1.065 1.19 1.1485  
Air spd
  40 40 41 41 42 44 46 50 56  
              0.5 1.5 2.5  
Wind spd
  -50 -40 -30 -20 -10 0 10 20 30  
  0 330 330 330 330 330 330 330 330 330 0
  5 560 594 627 660 726 825 957 1155 1518 5
  10 759 825 891 990 1122 1287 1551 1980 2706 10
  15 990 1056 1188 1320 1485 1749 2178 2805 3894 15
  20 1488 1320 1452 1617 1881 2244 2772 3630 5082 20
  25 1419 1551 1716 1947 2244 2706 3366 4455 6270 25
  30 1617 1782 2013 2277 2640 3168 3993 5280 7458 30
  35 1848 2046 2277 2607 3036 3630 4587 6105 8646 35
    -50 -40 -30 -20 -10 0 10 20 30  


By way of example we’ll look at three scenarios.

Scenario 1: Thermals to 2.300 m with 20 km/h of tail wind. Glide in distance with a safety margin of 330 m at goal is 30 km.

Scenario 2: Thermals to 1,650 m in nil wind. Glide in distance with a safety margin of 330 m at goal is just under 15 km.

Scenario 3: Thermals to 2,805 m in 20 km/h of headwind. Glide in distance with a safety margin of 330 m at goal is 15 km.


Reduce parasitic drag.

    Check out you’re A-frame on the ground. When you have set up the glider and put all the crap (eg GPS, Vario, Maps, Compass, etc.) on the A-frame walk to the front of the glider and have a look at what the wind sees. You can reduce your drag by simply lining up your instruments with your down tubes and making sure your maps are in a good streamline position. 

    Check your angle of dangle during glides. If your feet are too low when gliding then you are creating a heap of drag you can get rid of easily.

Pull up your tow bridle and store it out of the way.


    Always try to thermal with the smallest bank angle and as slow as you can. This will allow you to reduce the sink rate of your glider. If your are thermalling with a bank angle of 45 degrees in 1.5 m/s and you can decrease your bank angle to 30 degrees (given the thermal is big enough and of the same strength) your rate of climb with increase to 2 m/s. This means within 10 minutes of climbing you’ll be 264 m higher than the other guy.

    Also if your thermalling at 30 degrees in 1.5 m/s at 46 km/h and you slow down to 35 km/h you’ll increase you climb rate to 1.75 m/s. Again 10 minutes of climbing and your 165 m above the other guys.

    This is one reason some pilots climb away from you in the same air. They are flying flatter and slower. If you’re climbing at a steady rate (given you’re not too low trying to save your butt or the thermal is tight) try and widen your turn and slow down. I know that I don’t do this and I’m often content to maintain the same bank angle if I’m getting a good climb rate.


    Use other pilots as information sources rather than following them or letting them make decisions for you. One example of this is seeing a gaggle downwind of the course line. No point gliding to them (unless desperate) as when you finish climbing with them you have to punch head wind back to where you came from. 

    Try to follow the pilots better than yourself. If you fly with someone who is slower than you, you’ll slow yourself down by waiting for them. This means you’ll only be as fast as they are.

Hope these help.