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Old 4th Jan 2012, 09:16
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Piltdown Man
 
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You should be able to do this just by looking at the possible answers. Take drift. Will that be 10 or 20 degrees? Which way should be it be applied? For the range, it will be about 2 hours at 110 kts (less the headwind) but if you answer No. 2 first - you should be able to figure out No. 1. So if you are flying into a headwind, will you fly for more or less than half of your endurance? The only real question is here is by how much? Is is seven minutes (12 miles or so) or is it 14 minutes (30 miles)? The difference in the groundspeeds is about 20 knots - I'll go for 2 hours, 24 minutes.

As for headwinds and crosswinds, just remember 0.5, 0.7 and 0.9. The numbers 1 and zero or already in your brain. Use the numbers as sine or cosine, as appropriate for the intermediate angles of 30, 45 and 60 degrees. It's close enough for the real world.

So 70 degrees off track, as in this case, gives a crosswind of (0.9 x 20) 18 knots and a headwind/tailwind of (0.5 x 20) 10 kts.
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