The Norden Bomb Sight manual

the cross trail carriage moves to the right the

bottom of the telescope moves to the right.

I f

the cross trail carriage moves to the left the

bottom of the telescope moves to the left.

Thus

if the dove tail were not parallel to the fore

and

aft axis of the stabilizer you would have an in-

correct tilt of the telescope wich

would result

in a

delection error.

In bombing, under

any condition, the

bomb

will always trail directly astern of the airplane.

With no wind the collision course and the ground

track coincide.

This means that if the bombardier

has correctly

subtracted trail along the collision

course

and if he has properly synchronized on the

target, the bomb will hit its objective.

If a cross wind condition exists, the colli-

sion course and the ground track no longer coin-

cide.

If the airplane

flew directly over the tar-

get,

the bomb would fall down wind of the object-

ive; also it would be impossible to keep the cross

hairs on the target because the plane would drift

down wind.

It,

therefore,

becomes necessary to

crab the plane

into the wind and thereby move the

planes ground track upwind of

the collision course

so that the bomb,

trailing directly astern of the

plane, will hit

the objective.

plane

must fly upwind of the target is

distance which is

objectivearget

The distance the

cross trail

equal to the sine of the drift

angle

times trail in feet.

The drift angle is automatically set up by

the bombsight under these conditions

and is read

from the drift scale on the stabilizer. The cor-

rect drift

angle has been established,

under cross

wind

conditions,

when the fore and aft cross hair

remains on

the

target.

The sight stem is inserted in the sight stem

sleeve and is locked in

position relative to the

stabilizer with

a locking nut in the M-3 and a

locking pin in the M-6.

As the

plane is crabbed

into the wind and the

stabilizer turns under the

sight and

pivots the sight

stem

and dovetail. With

the eccentric disc back of

center, when

the sight

stem is pivoted, the eccentric stud moves through

an arc and in so doing carries the crosstrail car-

riage in translation.

The telescope

I S

tilted

through an

angle that will subtend

cross trail

distance on the

ground.

The telescope is tilted

independently of the vertical

gyro.

This is ac-

complished

as follows:

when

the airplane tilts

transversely, the gyro

remains vertical and holds

the cradle parallel to the gyro axis by the cradle