The use of the Dalton computer has now become rather academic, what many don't realise is that the primary use for this device was to actually calculate the wind. Before the days of sophisticated weather forecasting (The Met Office was developed to do this for the RAF) crews on long range flights had very limited wind information to work on.
Flying three different headings and measuring the drift by looking vertically downwards through a drift sight (ideally over the sea) drift lines could be plotted on the computer to give a 3 drift wind and from that ground speed could be deduced.
With the advent of doppler radar in the early 60s by plotting Heading/TAS and Drift/GS the local wind could be determined and then used for the next 20 minutes.
In all these cases, and when calculating an Air Release Point for objects dropped by parachute, the resultant wind is downward.
In most cases the Dalton was only used to calculate actual winds along a route so that they could be given the met man at the end of the flight. It was not used for preflight planning; a much simpler tool was available called a Drift and Wind Component Template that was calibrated for the aircraft TAS
Last edited by Whopity; 26th February 2008 at 08:18.