Hello
As is widely known a major contributor to the defeat of the Luftwaffe in the Battle of Britain was radar… airborne radar, or more precisely the fleet of early warning aircraft (AEW) of the RAF.
Radar was used by the RAF for some time, but it was its force of AEW aircraft (or Air Controlled Interception, as it was known at the time) that helped turn the tide in favor of British forces in the BoB.
The first airborne and control aircraft were the adapted versions of the Bristol Bombay (the Bristol Bluebird ACI.MK.3), that entered service in 1935.
It is amazing that it was only in the middle of WWII that other Air Forces (namely the Luftwaffe) realized the tactical and strategic value of this system and started fielding their own.
We might say that it were the lessons learned form the BoB that shaped the future of the AEW aircraft; the Luftwaffe and other air forces introduced their own AEW aircraft and the RAF fielded even more capable ones.
Although some Bristol Bluebirds were used in the BoB, it was a version of the Armstrong Whitworth 23 (the AW Osprey ACI.MK.4) that was the main AEW aircraft used by the RAF at the time.
Although performing very well in the BoB and in the following Blitz, the Osprey had some serious performance limitations and soon a replacement was ordered (a version of the Avro York transport, the Avro Hawk ACI.MK.7)
