Cradle differential action
RESTRICTED
0. Bomb-
sight
Gyro
connecting rod.
If there is no change in position
of the cross trail carriage the cross trail conn-
ecting rod stands fast
and rotation of the cradle
I S
about the cradle end of the cross
trail conn-
ecting rod.
When
the cross
trail connecting rod acts
(assuming the
plane is not tilted transversely).
cradle differential lever pivots
about the
cradle
end of
the cradle connecting rod,
and the
resulting
motion of the cradle differential lever
pivot pin
the M-s the cra
amount of
trail that
can be set in on the cross trail knob is 23 mils.
The
maximum
amount of trail is about 70 mils.
We have stated that if the drift is correct
the bomb,
when
released,
will hit its objective.
This is
Slightly in error because when the optics
tilt a slight error causing an overshot occurs.
The amount of
this error is known as Range Compon-
ent of Cross Trail.
The formula for Range Compon-
ent of Cross
Trail is trail
times l minus the co-
sine of
drift angle--T(-Cos e).
The bombsight gyro assembly consists of
a
case
which is of
two parts (held together
with
gyro caging pin,
leveling bubble
tubes,
fore and
aft and
transverse gyro
balance weights,
two carbon brushes, armature,
field, two retor
bearings,
and rotcr.
The bombsight gyro rotor is an inverted cup-
shaped wheel driven clockwise at about 7800 r.p. m.
direct current. The gyro
spins on an axis,
which
for the correct solution
of the bombing
problem must
be vertical.
Around the
top and low-
er edge of the rotor are 10 screws.
These
screws
are balance screws and are never
removed
axcept
when
balancing the gyro.
inside the wheel and
bolted
to it is the armature of the motor which
drives it.
The entire wheel or rotor is enclosed
gyro casing.
The upper part of the case
carries
the gyro caging pin, the upper rotor bear-
ing:
the
transverse leveling
bubble tubes and the fore and aft and transverse
weights.
The lower half of the gyro
carries,
on its inside, the field colls,
fit between
the gyro rotor and motor armat-
lower rotor bearing.
Extending through
lower casing and at right angles
to the comm-
utator are the brush
tubes which hold the carbon
brushes.
Attached to the bottom of the casing are
79