The Norden Bomb Sight manual

speed after adjusting for high speed and also

be sure that the brake springs exert enough pres-

sure against the brake ring to hold the altitude

knob in any position.

The altituce knob is important in the solu-

tion of the boncing problem because

the springs

corero: tre steed of the telescope motor.

ready io consider the inter ..

of the sight.

we remove the five

holding the rate end and remove the rate end.

rate end, motor half, houses the

telescole

assembiy, displacement and

rate knob assembly,

search knob and disc assembly.

D. Teles-

cope

Motor

Assem-

bly

Fig. 33

E. Rate

and

Dis-

place-

ment

Knob

Assembly

The telescope motor assembly consists of the

following.

parallel wound constant speed motor,

field coils, carbon

brushes,

governor,

and necessary bearings,

screws and wiring.

The telescope motor drives and controls the

speed of the disc. The speed of the

motor is

controlled by having a set of breaker points wired

in series with the armature.

The breaker points

are kept closed by the

tension

of the altitude

springs until the governor overcomes that tension.

As the motor speeds up the arms of the gover-

nor tend to become parallel,

thereby puiling

the

connecting links and collar

toward the

center of

pivot of the

governor and at the same time moving

the breaker

with them.

The breaker arm is

attached

to

the

altitude shaft.

As the breaker

arm is pulled

toward the governor the

breaker arm

pivots the altitude shaft, overcoming the tension

of the altitude

springs,

and breaks the contact

between the

points.

circuit to the telescope

motor is broken.

The motor slows down; the pull

of the governor

becomes less than the tension of

the altidude springs and the breaker points are

closed

and the circuit is again completed.

is so rapid that the speed of the telescope

motor

remains constant.

This assembly consists of rate knob (inner

knob), displacement knob,

displacement clutch en-

gaging knob

shaft,

displacement shaft, bevel

pinion and intermediate gears.

The displacement knob enables the bombardier

to

move

the optics independently of the rate of

drive.