Transition of the bombing problem to the sight
RESTRICTED
Transition
of Bombing
Problem To
The Sight
1. General
when the cross
intersected the
target, the
should hit the objective.
However, the Nor-
den Bombsight, or any synchronizing sight, will de-
termine the correct dropping
angle provided the
sight is accurately calibrated,
correct data
set into the sight, namely, trail and actual time
of fall, and
siaht is correctly synchronized.
angle as
The sight detfalines the correct dropping
follows:
for the particular type
of bomb is taken
from trail charts.
The number of
mils of trail is set into the sight by rotating
the trail arm-from zero mils
to say 50 mits as in-
dicated by the scale on
the trail plate.
Actual
time of fall, which is also taken from charts,
set into the sight.
This is done by positioning
the altitude knob
so that the proper disc speed
may be attained.
If 20 seconds is the actual time
of fall, the disc speed for an M-6 sight and up
is computed
use of
disc speed
formula:
Disc Speed = Sight constant divided by the actual
time of fall.
In this case DeS. = 5300 = 265
R. P.M.
a tachometer and position altitude knob
until the disc speed
of 285 r.p.m. Is obtained.
Make three or four checks at 6 to 10 second inter-
vals to be sure the disc speed
is correct.
when trail was set in, the roller was posit-
loned from
center of the disc a distance pro-
portional to trail.
The correct rate of drive for the optics Is
determined by positioning the roller whole range
distance from the center of the disc. This Is ac-
complished by rotating
the rate knob and through a
system of gears the spindle screw is rotated, caus-
ing the
roller
to be moved upward on the spindle
screwe
When the roller turns it transmits through
a system of gears and by
means of tha telescope
cable the
drive
to the mirror in M-4s
and up and
to the telescope in the M-3.
When the
Intersection of the cross halrs re-
mains on the target, as
to fore and aft movement,
the optics are driving at an angular speed procor-
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