NavList:

I thought readers might wish to see how John Howard’s Navigator would have obtained the wind velocity from three drifts from a drift sight using his Dalton computer derivative, please see photos below.  I’ve done it for an initial heading of 360 degrees, then 045, and then 315.  I’ve done it for an aircraft flying at a true air speed of 150 kts.  Sorry John, I’ve only got a low speed slide.  I divided the speeds on my high speed one by 100 to use in TIKI.  I’ve also added a vector diagram drawn on squared paper (one square = 10 kts) to show what’s happening.

In fact, you could probably manage with just two drifts, e.g before and after a turning point, but using three gives a better idea of their reliability from the size of the cocked hat.  (Not to mention the opportunity for a symmedian point Bill L). DaveP

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