BFV,if you go to the `flightglobal` website,archives,and look up 1956-1794/4 pdf file ,that might give you some background.Further searching for` heli autopilots` will also get you some more.If you want simplicity,remember Igor started by flying around his garden,in bowler hat and overcoat,next day he wanted to go further,and a bit faster,so he put a canopy on it,but got tired,and decided he needed some help,from a few mates called Sperry,Honeywell,Lear,Elliot ,who made `autopilot/auto stabs` things for aeroplanes; he could now go further,and in bad weather;he didn`t want to pay for another pilot to help all the time,and sometimes the system failed,dramatically,in cloud,so he had to work hard;so,he put 2 systems in his helo,now a bigger helo,to carry his military friends;he had also sold a few helos over here,and another mate called Louis Newmark knew a bit about electronics and `wiggly amps`,and he really improved it a lot.Igor could now fly day /night/IMC and his mil. friends flew his helos out/from their boats,and try catching big fish-submarines, by dipping their `ear-trumpets` into the water,and listening,but it was difficult; so LN designed an automatic`transition down/up`,and hover over the water,whilst the ear-trumpets were deployed, AFCS that could fly the helo in all weathers
and sea states,and all the overpaid pilots did was sit on their hands.Pretty good .Igor and his mates were very happy,especially the `Glovers` at Yeovil ,who made his helos,except they always had difficulty with windows,which leaked in wet weather..not good for Louis`s electronics,even to this day!!
Nowadays,its possible with improved nav systems(GPS/datalink) to fly coupled approaches to airfields and ships,and in some cases without a pilot.....B