The Norden Bomb Sight manual

M-3

Fig. 50

M-6

Oiling

b.

Adjust low altitude, outer

spring. next.

Turn counter-clockwise

to decrease disc speed and

clockwise to increase disc

speed.

Always loosen

set screws before

attempting to adjust

spring.

The high altitude spring is approximatsly half

wound before the

iow altitude spring comes into

operation.

Minimumspeed 117 plus or minus 1/2 ..P.m.

Medium speed-202

Maximum speed 417 " "

After minimum

and maximum disc speed are ad-

justed rotate the altitude knob until the clutch

holder of the iow altitude spring barely contacts

the clutch no!der of the high altitude spring.

correct medium disc

speed is not obtained

ad -

just the stationary telescope motor point.

check minimum and maximum and then recheck

medium

disc speeds.

Adiust the

altitude springs to give the following

speeds.

Shift on low:

Low

Medium

101 plus or minus 1/2 r.p.m.

Fast

246 plus or minus 112 r.p.m.

Shift on high:

LoW

Medium

348-350

Fast

W.th the gear shift on low, the low altitude

spring should

cut in at 145,

and,

the gear

shift in hich position,

altitude spring

should cut in

at 348

to 350.

This can be

accomplished by removing the

outer case,

loosening

set screws and by rotat-

ing the

cases to obtain the correct tension on

the springs.

altitude knob creeps,

brakes, The brakes are the two flat

leaf springs,

screw through

the center, which apply a

tension against the fiber brake ring. Only the

calibrated knob needs to be removed for this

adjustment.

Oil the

bearings with one drop of light oil

if bearings

are removed and cleaned.

PRECAUTION:

must be removed for some reason, the spring cases

be very careful not to bend the

springs.

the springs are bent out of shape

the tension

applied will be different and it may

be difficult or

impossible to correctly calibrate

the altitude

knob.

3.

If

the

Re-

with

the

low

the

the

with

outer

must

be

Once

out

of

shape