On the SDT stuff, don't forget the old trick - second nature to aged pilots
comme moi - that 6 mins is one tenth of an hour, so you travel one tenth of the speed.
Was reminded of this recently when trying to explain the "whizz wheel" on the back of the DR Computer to some Air Cadets. The phrase "circular slide rule" clearly meant nothing - "Wotsa slide rule Sir?
" - so we tried a practical example:
Give me a speed - Bloggs. 130 knots Sir.
Give me a distance between 45 and 90 nautical miles - Trenchard. 52 Sir.
Too easy sez I, putting down Whizz wheel - it's 24 minutes.
Teenage jaws could not have dropped further or quicker if I'd made sparks come out from under my fingernails.
Then came the satisfying grins when I explained:
130 kts is 13 miles in 6 minutes, 4 thirteens in 52, 4 x 6 = 24!
And there are more "tricks" like that of which Yoof seems unaware....
