Use the wind side of the Whizz-wheel.
(the following is the wind-down method)
1. Spin the rotating part (inner scale) so index points to 90 (wind direction)
2. Set the centre blue dot (wind index) over the 100 speed arc.
3. Mark (down the way) the wind speed in at 80 (80 because 100-20(wind speed) = 80)
4. Rotate the inner scale to set the true track, 180 (180 under index)
5. Move the vertical rectangle part down (in this case) until the mark you made sits on the 80 line. (80 because that's the groundspeed that you need to maintain)
6. Now you need to apply the drift, in this case it is right drift of 15 so rotate inner scale right by 15. Index now is 165. (you could've just done 180-15 also). The drift is shown as that's where your put the mark (step 3)
7. True heading is 165
8. Blue dot (not the one you made) is over the TAS which is 78kts.
Pretty sure this is the way to do it - I'm sitting my Nav exam on Sunday - if I'm wrong....oh b****cks.
I've have made a tutorial on how to do various calculations with the whizz-wheel and also complete a flight plan using it. PM me your email address if you want a copy.
Do you have the PPL Confuser? Its' got really good explanations on how to do various things with the whizz-wheel. Worth it.
Cheers,
Last edited by whoswho; 5th March 2009 at 20:33.