Evening star., 1941-02-18
Faster Range Finder
Directs Britain S New
Night Aid Defense
Four Times os Many
Raiders Being Brought
Down in Dark Now
BY the Associated Press.

BY the Associated Press.
LONDON. Feb. ia range
finder with the speed of an electric
eye is directing the fire of Britain's
anti-aircraft guns in what has been
described here as an entirely new
type of co-ordinated ground
warfare against night bombers.
Increasing experience of the gun
crews and picked night fighter
pilots in operating in the dark, plus
a new night defense scheme and
advantages gained by use of the
faster range finder, were said to
have enabled the British to knock
out of the skies greater numbers
Of invading planes.
Although German air activity
over Britain in January was on a
comparatively small scale, British
anti aircraft gunnerS were credited
WI h bagging II night raiders. Night
f?htcr planes reported bringing
Gown four and three crashed for
reasons not disclosed officially.
So far this month. seven have
been destroyed-all but two by anti
aircraft fire.
Kills" Now Four Times Greater.
Last Nocember, a month of heavy
warfare. only IA night raiders were
shot down, although they came in
hundreds. In December, only 10
we're bagged at night. That month.
too. the raiders were over England
in large numbers night after night.
Sources here estimated not more
than 1900 Nazi planes were over
Britain at night during the whole
month of January, whereas in No
vember the total of night raiders
was thought to have been 5000.
On the basis of these figures, the
January ratio of kills" was approx
imately four times greater than
during November.
The new predictor orange finder
has been a hush-huSh device. but
this much has leaked through the
official secrecy: 1t is a sort OF light
ming calculator which at least makes
a stab at getting around the big
difficulty in range finding-the
ratio between the speed of attack
ing planes and the speed at which
the sound of their motors travels.
Coordination and Experience.
The old projectors failed to work
satisfactorily because by the time a
plane flying at $4,000 feet was heard
by mechanical ears it would be as
much as miles from where it was
detected.
Coordination of defenseS and i'll
creasinG experience we're said. how
ever, TO be even greater factors
toward solving the night bomber
problem than the use Of the new
range finder.
The new tactical system includes a
combination of the use of search
lights anti-aircraft guns and fight
er planes equipped with two-Way
radios by which they can be guided
by ground observers.
For ground observation purposes.
the sky is divided into cubes of re-
Sponsibility, with each observer as
signed to watch specific cube
When the action starts. guns and
searchlights switch from one cube
or group of cubes to another. letting
night fighters take over. and vice
versa.
Pilots Specially Trained.
Night fighter pilots - especially
picked for ability to see in the dark
Gc- special diets. including a heavy
ration Of carrots and cod liver oil.
They also receive special training.
md there are a number of R. A. F.
nosts where the night air is almost
literally filled with students of the
special technique.
These night pilots are using mostly
Bolton Paul two-SeaterS. Blenheim
fighter -bombers and Hurricanes, but
some American-made planes also are
coming into use.