The difference between magnetic and compass is deviation.
Positive deviation or variation is Easterly.
C-----D----M----V----T
200 +1(E) 201 31W 170
Find the heading in degrees TRUE by using the deviation and variation - see
above (170).
Drift is from Heading TO Track, and Heading is calculated (from
CDMVT) as 170ºT, therefore Drift = 10º Right (or Starboard, depending on your
type of Whizz Wheel).
So the drift is 211degrees (from the VOR radial) –
201degrees (magnetic from above) = 10degrees STBD.
Get the whizz wheel out. Centre dot on the TAS (390), TRUE heading (170) set at
the top of the wheel and then put a mark on the drift of 10degrees STBD (211 -
201) at a G/S of 360 kts.
Rotate so the mark is under the dot and read out TRUE wind direction and
speed...