This kind of thing is required to be worked out in your head when your doing the CPL
It is? It wasn't when I did my CPL
Rowley, there's nothing wrong with using the Max Drift rules in practice. If you do need to work things out in flight (not for the CPL, but for any other reason), or even on the ground if you don't have a flight computer handy, that's fine.
But at the end of the day, it's just an approximation.
However, Dufwer was after the exact formula, not an approximiation. Just purely as a theoretical exercise, because we all know that neither the forecasts nor our flying are accurate enough to get any real benefit from dusting off our scientific calculators to get the exact numbers - but that doesn't stop it being a useful exercise in trigonometry, as long as we all agree that that's all it is.
This thread has definitely got my brain-cells going... I had a go at solving this before PA28 and Oxford Blue posted, but couldn't remember enough of my A-Level maths to be able to do it. It's slowly coming back to me now though
FFF
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