The Norden Bomb Sight manual

are the

and displacement knobs. The

displacement knob

allows

bombardier

displace the optics independently of the rate

of drive.

The inner knob

is the

rate knob, and

angular speed of

the optics.

will discuss

these knobs more fully later.

At

the very bottom

of the rate end is a knob which

the rate end at an angle.

This knob is

called the search knob and rapidly. displaces the

optics.

Situated within the displacement knob is

a locking clutch (locked when pushed

in and un-

locked when

pulled out.) This clutch merely en-

gages the displacement knob.

The search knob must

never be used

when

the clutch is engaged.

The

rate and displacement knobs are located together

so that they can both be used at one time by

double gripping.

1. Sight

Assem-

blies

A. Course

Knob

Assembly

Fia. 31

On the rear and lower part of the sight case

Is attached the course knob assembly.

This ass-

embly consists of the turn knob,

drift knob,

the turn worm,

the drift worm

and the

intermed-

iate gears which drive

the drift worm.

The turn

knob is fastened to the inner turn rod

and carries

the

turn worm directly.

The turn

worm

acts

dir-

ectly upon

the

rack

of the

stabilized sector.

The drift knob is fastened to the outer shaft

which is connected to the drift worm

through two

gears.

worm. acts

directly

upon the

drift gear which

is collared around the sight stem

sleeve.

The drift worm

is mounted in a swivel

housing which

is adjustable so that proper clear-

ance between the drift gear and drift worm may

be maintained.

The assembly is fastened

to the sight case

with seven screws.

The course knobs are used to

set up the course of the airplane in relation

the

line

of sight.

When the turn knob is rotated

the turn

worm.will track

around

the rack of the

stabilized sector which is stabllized by the bomb-

sight clutch.

The drift worm will drag the drift gear as

the sight tracks about the rack of the stabilized

sector.

when the drift gear turns the stabilized

is displaced and a reading is registered

on the

PDI. The PDI tells the pilot which way to

turn the plane to bring it back to straight flight.