The Norden Bomb Sight manual

tion of the rate

quadrant is to sight through the

positioning

the telescope

indicator

opposite the rate

mils on the

tapendicator and

read the number of

the point upon which

transverse hair lies.

divide this number of

mils by

1000, and

the exact tan function position

of the rate quadrant will be

revealed.

(NOTE: If the transverse hair is out

of relation-

ship to the position

of the tel. quadrant,

the exact position of the rate quadrant will not

be revealed by the use of the more accurate method

just cited.

case of any discrepancy

between

the mathematical

and mechanical

answers, this

be first checked for.)

Compare the position of the rate guad-

as actually found to exist in terms of tan

function in the bombsight, with the position of

the rate quadrant as it should exist according to

the mathematical

above.

E. If the results are consistent

but in error,

for example a 5 mil plus error exists at all points

the usual causes ar foller not zeroed.

Worn roller.

(3) Calibration

of the trans-

verse cross hair.

F. If the results are inconsistent, showing plus

or minus errors

be

checked

, and the cabie in-

spected for kinks or enlarged

Large

errors in the direction of increasing

dropping

angles, should lead one to suspect that the disc

correctly transmitting its rotation to the

roller.

If records are kept of the values found

at each 50 hour inspection, incipient troubles

may be discovered.

(1)

Slipping roller.

(2)

Erratic disc speed.

Foe range of dropping angles.

different problems to give a

optics

after

the

Then

then

{n

should

function

in

the

bombsight,

with

the

position

of

1)

not

zeroed.

erratically,sheaves

should

for

dirt

in

the

is

not

wide

range

of

dropping