Calculating actual wind
If you are flying an aircraft not equipped with an air data computer, is there a formula that allows you to work out exactly what direction the wind is coming from and its strength by seeing the single drift on the RMI and the groundspeed from a DME unit? Given a wind direction and strength from the MetOffice, I have no problem calculating the theoretical single drift and groundspeed to be expected, but I am more interested in the real world case where you have to work backwards from the information presented to you on your instruments. Am I correct in thinking that there is such a formla/formulae, and, if so, what is it/are they and in what order do you go about solving the wind? Perhaps I am wrong and you need information not available to you to solve the exact wind direction and speed.
Any ideas?
Thanks