The Battle of Britain Five Months That Changed History, May—October 1940 by James Holland (z-lib.org).epub

fields. Billy Drake was also back in England, although not with 1 Squadron.
Although recovered from his wounds, he had been posted to 6 Operational
Training Unit at Sutton Bridge as an instructor. It was Billy’s job to make
sure the pilots now coming through training were fit to be sent to
operational squadrons. Most were Volunteer Reserves or overseas pilots. To
begin with, he would take them up in a Harvard or Miles Master two-seater
trainer, and when satisfied that they could handle themselves, would send
them up in a Hurricane, following in his own. They would practise
formation flying and then Billy would try and teach them rudimentary dogfighting.
His combat experience was invaluable.
Yet while it was the fighter aircraft that were to shoot down enemy
aircraft, there were other weapons in Dowding’s armoury – weapons that he
hoped would greatly improve the efficiency, and chances, of his pilots. Now
dotted along the British coast was a series of twenty-one high metal masts,
as much as 360 feet tall like giant Meccano. Also standing sentinel looking
out to sea were thirty shorter, more squat stations. These together were
Britain’s RDF, or radar, chain, a key component in Dowding’s early
warning system.
The genesis of such a system had begun six years earlier, in 1934, when
Harold Wimperis, Director of Scientific Research at Dowding’s then
department in the Air Ministry, had set up a committee under the wellknown
physicist Henry Tizard, with the idea that it should investigate the
possibilities offered by science to assist air defence. Wimperis immediately
consulted Robert Watson-Watt, a Scottish scientist who had for many years
been studying high-frequency radio and atmospheric research. Wimperis
had asked Watson-Watt first about the possibility of developing a ‘death
ray’. This Watson-Watt thought unlikely, but he did have ideas about how
radio wave reflections might be used to detect, rather than destroy, aircraft.
Watson-Watt put forward his theories on ‘Detection and Location of
Aircraft by Radio Methods’ to the Tizard Committee. In essence, he argued
that an aircraft meeting a short-wave radio pulse would act as a kind of
radiator, and reflect the signal, which, if powerful enough, could be picked
up. The time lag, measured in microseconds, between the emission and
reception of this reflected signal could be shown on a cathode ray tube as a
blip of light on a fluorescent screen. Thus once a suitable time base was
established, the distance of the aircraft from the radio base could, in theory,
be worked out. The Tizard Committee was impressed and asked Dowding