Whole range and actual time of fall
RESTRICTED
From tables, trall
and actual time of fall
are deterained for a particular type of bomb, for
a given altitude and calibrated
indicated
speed.
It is known that whole range equals Velocity
of Closure multiplied by the Actual Time of fall.
Yelocity of Closure is computed from cali-
brated indicated air speed by the use
of tables.
First drue air speed is determined and then ground
speed which is
equal to true air speed when there
is no wind.
If
there is a headwind, then the
around
speed is decreased by the number of miles
per hour the headwind is blowing.
Thus, if a true
air speed of 200 miles per hour is computed and
headwind
20 miles
per hour, the
around speed is 180 miles per hour.
Ground
speed
is also Velocity of Closure. if there is a tail
wind of 20 miles pee: hour and a true
air speed
of
200 miles per hour,
the ground speed
is 220 miles
per hour.
Thus, from the information given and computed,
namely, altitude,
traii, actual time of fall and
Velocity of Closure, the bombing problem
may be
solved
for the actual range angle.
However,
the
sight will also establish
the correct
actual
range
anale for the bomb to hit the target.
The sight
will do that,
provided
it is correctly calibrated
and the given
information
is correctly set into
the sight and provided
further that the
sight is
correctly synchronized by
the bombardier.
If the information concerning a
bombing prob-
lem is to be preset into the sight, the trigonomet-
ric functions must be understood.
trigonometric
function
is the expressed relationship between the
sides and angles of a
right
triangle.
In the solution of the bombing problem only
one angle is essential.
That is the
angle formed
by the altitude and
the hypotenuse.
The trigono-
metric functions of this angle are:
Sin LA
opposite side
divided
by
the hypotenuse.
Cos
LA
adjacent side divided by
the hypotenuse.
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