Wind Calculations
 

Hi,

I would be grateful if anyone can provide me with any advice on an easy way to mentally calculating what heading to steer whilst flying. e.g. w/v 250/5 and the course heading is 120, What is the heading to steer.

Thanks.

Work out your max drift = 60 * Wind Speed / TAS.

Your drift will be equal to max drift if the wind is a >= 60deg cross wind. It will be three quarters if the cross wind is 45deg, half max drift if the cross wind is 30 deg, quarter if 15deg, you get the idea. Use your analogue watch face to get the fraction.

Assuming 100kts TAS. You max drift is 5 * 60 / 100 = 3deg. Your cross wind angle is 250-120 = 50 deg so you could round your drift to 3 (more than 3/4), wind from starboard so you should initially steer 122.

If the wind were 150/20 then your max drift would be 12deg. The cross wind would be 30deg and so your drift would be 6deg port so would need to steer 126.

Thanks for that, the worked out example made sense.

The max drift is a magic tool for working out headings. If still not convinced, check out a few examples on a whizz wheel and you'll find your within a few degrees.

anyway, i found that hardest part of teaching this method in the air is peoples lack of mental capacity to work out how what the angle between the track and wind. and hence how much max drift to apply on diversions or replans. it's much easier to use the DI (or OBS if available) and imagine an arrow for the wind. this will help you to 'see' the angle between the track and wind.