ARMAMENT
B- 2 9 A IR PLANE

ARMAMENT
TABLE OF CONTENTS
. PAGE
ARMAMENT (GENERAL DESCRIPTION)________________________________________.._______ 2
BOMBING EQUIPMENT ----------------------------------------------------------------- ···- 2
BOMBARDIER'S CONTROL STAND --------------------------------··------------------ 3
BOMB CONTROL SYSTEM ---------------------------------------------------------------- 5
BOMB CONTROLS ----------------------------------------------------------------------·_________ 7
COORDINATING UN IT ----------~--------------------------------------------------------- 8
BOMB BAY DOORS AND BOMB RELEASE COORDINATING UNIT______ 9
EMERGENCY BOMB RELEASE SYSTEM ---------------------------------------------- l 0
INTERLOCK AND EMERGENCY BOMB CONTRO'LS____________________________ 11
INTERLOCK SYSTEM ----------------------------------------------------------------··--- ____ 12
EMERGENCY BOMB DOOR RELEASE SYSTEM ----------------------------------~- 12
BOMB DOOR DRIVE _···----------------------------------------------------------------_____ l 3
BOMB DOOR LIMIT SWITCH______________________________________________________________ 14
BOMB BAY DOOR ACTUATOR --------------------------------------------------------- 16
BOMB DOOR CONTROL CIRCUIT -------------·------------------------------------------ 18
BOMB CONTROL CIRCUIT (DIAGRAM)____________________________________________ 19
BOMB CONTROL CIRCUIT ----------------------------------------________________________ 20
RS-2 RACK SELECTOR RELAY --------------------------------------------------------~---- 23
OPERATION OF RS-2 RACK SELECTOR RELAYS________________________________ 27
BOMB INTERVAL RELEASE CONTROL UNIT (INTERVALOMETER_______... 30
BOMB INTERVAL CONTROL UNIT______________________________________________________ 31
A-2 BOMB RELEASE ---------------------------------------------------------------------·-- __ 32
RELEASE UN IT ACTUATOR _______________________
____------------------------------------ 35
AX-5 AUXILIARY BOX -------------------------------------------------------------------_ 36
TIME DELAY RELAY -----------------------------------------------------------------------· 37
BOMB RELEASE FORMATION LIGHT ----------------------------------------------- 38 .
BOMB SHACKLES -------------------------------------------------------------------------- 38
BOMB RELEASE SEQUENCES ------------------------------------------------·----------- 40
BOMB RELEASE SEQUENCE CIRCUIT_________________________________________________ 41
BOMB RACKS (TEXT) ---------------------------------------------------------------------- 43
BOMB RACKS (ILLUSTRATION) ----------------·----------------------------------------· 45
BOMB HOISTING -------------------------------------------------------------------------· __ 47
HOISTING OF 500 POUND BOMBS ------------------------------------------------- _ 48
HOISTING OF l 000 POUND BOMBS ---------------------------------------------·--- 50
HOISTING OF 1600 POUND BOMBS -----------------------------------------------. 51
HOISTING OF 2000 POUND BOMBS ---------------------------.------------------- 52
HOISTING OF 4000 POUND BOMBS ---------------------------------------------- 53
DEFENSIVE ARMAMENT --------------------------~-______________________________________ 54
FORWARD GUN AND CAMERA LOCATIONS ----------------------------------- 55
REAR GUN AND CAMERA LOCATIONS -------------------------------------------- 57
PRIMARY AND SECONDARY GUN CONTROL ---------------------------------·- 62
ARMOR PLATE ·-----------------------------------------------------------------------------~-- 63

RESTRICTED 8-29 FAMILIARIZATION
AND MAINTENANCE
ARMAMENT
GENERAL DESCRIPTION: The B-29 airplane is
equipped with a General Electric Central
Station Fire Control System. This defensive
armament consists of two upper and two lower
turrets each mounting two .50 caliber machine
guns a·nd a tail turret which mounts a 20 milli-
meter cannon in addition to two .50 caliber
machine guns. All guns in these turrets are
aimed by means of computing sights and are
remotely controlled from one or more of the
five sighting stations.
Seven weight classes of bombs, carried on
interchangeable bomb racks in two bomb bays,
comprise the offensive armament of the air-
plane. The maximum bomb load is 20,000
pounds.
BOMBING EQUIPMENT
GENERAL DESCRIPTION: Bombs norm a 11 y
(armed) are released from the bomb racks
electrically. The bombs are carried on the
racks by shackles which contain the mechanism
for releasing the bomb lugs and retaining or
releasing the arming wire. Energizing a sole-
noid in the release box trips two spring-loaded
arms which operate the two shackle levers to
release the bomb and retain the arming wire.
The release circuit is closed either through the
bomb sight switch or the manual release
switch.
Bombs can be dropped either singly or in train
by use of the bomb interval release unit
(intervalometer) the settings of which deter-
mine the number of bombs in a train to be
dropped and their spacing when they hit the
ground. A limited selection of the sequence in
which bombs may be dropped is made pos-
sible by the four bomb group selector switches
and their rack selector relays. The several
dropping sequences, depending upon the
racks installed, were chosen to minimize the
adverse effect of unbalanced bomb release
on the airplane's center of gravity.
When abandoning the airplane, the emer-
gency exit for most crew members is through
the bomb bays. All of the bombs can be jetti-
soned by either of two cable-operated sys-
tems. When time permits, the bomb doors are
opened electrically and the bombs released
by the bombardier moving the door control
level to OPEN and the bomb release lever to
SALVO. When immediate action is important,
any of three emergency bomb release con-
trols can be used to drop open the bomb bay
doors and jettison the bombs. Emergency
releases are located at the bombardier's sta-
tion1 the pilot's station and the aft pressurized
compartment.
These emergency controls first disconnect the
bomb door actuating screws from the doors,
permitting them to drop open, and then move
the selector bars in the bomb racks to trip me-
chanically the release boxes. When mechani-
cally tripped, only the bomb release lever of
the shackle is operated by the release box per-
mitting the arming wires to drop free with the
bomb and in this way release the bombs
unarmed (fuse inoperative).
Bombs cannot be released either electrically
or mechanically until the bomb doors are fully
open because the circuit through the release
switches cannot be completed until the doors
open fully to operate safety switches which
complete the circuit to the bomb safety relay.
This relay supplies power to the bombsight and
manual release switches. In addition, the selec-
tor bars cannot be moved from the LOCKED
position to the SELECTIVE position (which
unlocks the mechanisms in the A-2 release
boxes so they may be tripped electrically or
manually) until the doors have fully opened.
The interlock mechanism is operated by the
doors through a cable system. The manual
bomb release switch is located on the floor left
of the bombardier's seat.
A switch on the bombardier's control panel
operates three automatic cameras installed in
the tail section near the auxiliary power plant.
To the bombardier's right is a wooden table on
which the bomb fixation chart is attached.
2 ARMAMENT

RESTRICTED
EMERGENCY BOMB RELEASE-------.
AND RESET WHEEL
ASH TRAY
8-29 FAMILIARIZATION
AND MAINTENANCE
,..___ _ _ BOMB RELEASE LEVER (LOCK POSITION)
.__---BOMB BAY DOOR SWITCH LEVER
(DOORS OPEN)
BOMBARDIER'S CONTROL STAND
LOCATION: To the left of the bombardier on the OPERATION: On the stand, convenient to the
forward face of the bulkhead at Station 44. bombardier's left hand, are the bomb release
lever, the bomb door switch lever, and the
emergency bomb release and reset wheel.
ARMAMENT 3

RESTRICTED
The bomb release lever positions the selector
bars in the bomb racks by means of a cable
system. The lever can be placed in three posi-
tions: LOCK, SELECTIVE, SALVO. The operat-
ing point of the SALVO position varies with
thermal change and is labeled SALVO NOR-
MAL TEMPERATURE and SALVO COLD
TEMPERATURE. A knob on the top of the
handle is pushed down to unlock the lever from
the LOCK and SELECTIVE positions. To move
the lever forward of SELECTIVE (to the
SALVO position), the knob must be down far-
ther, thus preventing accidental salvoing of
bombs when moving the lever to SELECTIVE.
The bomb door switch lever is moved forward
to open the bomb doors. A cam on the bottom
of the lever pushes a hinged bracket holding a
microswitch down, depressing the microswitch
pin against a screw in the bottom of the stand
cover. Loosening a locknut on the screw per-
mits adiustment of the switch operating point
with respect to the lever travel. The top of the
lever handle must be pushed down to unlock
B-29 FAMILIARIZATION
AND MAINTENANCE
the lever from CLOSE. When the lever is
pulled back to CLOSE, the top of the handle
must be pushed down again. In the CLOSE
position, the head of an adjustable screw on
the rear side of the lever strikes a micro-
switch button to close the circuits to solenoid
switches.The bomb bay door motors are wired
in parallel so both are energized at the same
time.
A lug on the bomb door switch lever projects
within the bomb release lever travel to pre•
vent the bomb release lever from being
moved out of t~e LOCK position if the switch
lever is locked in the CLOSE position.
For emergency jettisoning of the bombs from
the bombardier's station, an emergency bomb
release and reset wheel is located at the
inboard side of the bombardier's stand. By
reversing the wheel after an emergency
release, the coordinating unit is reset so that
the bomb doors may again be engaged by the
door screw mechanisms and the doors then
closed electrically.
4 ARMAMENT

RESTRICTED B-29
F"AMILIARIZATl □ N
AND MAINTENANCE
BOMB CONTROL SYSTEM
PURPOSE: To position selector bars in the bomb
racks to operate mechanically the A-2 bomb
release boxes.
OPERATION: Selector bars are flat bars of dural
mounted to slide vertically in each of the bomb
racks. Cam slots (see illustration) are cut in
the selector bars at each release box location.
A roller, pinned to a short crank arm, fits in the
cam slot so that the crank arm is rotated when
the selector bar is moved up or down. A
tongue on the A-2 release box salvo coupling,
fits into a slot in the axle of the crank arm. Thus,
when the selector bars are in their lowest posi-
tion, all of the A-2 release boxes installed on
the bomb racks are locked SAFE so that the
bombs cannot be dropped either electrically
or mechanically. With the selector bars in mid-
position, the release boxes will be in SELEC-
TIVE, unlocking them for electrical release. As
the selector bars approach their highest posi-
tion, the release boxes are tripped mechani-
cally, salvoing all of the bombs. These positions
are marked on the selector bars in reference
to a pointer secured to the rack.
The position of the SALVO portion of the cam
slots varies from the bottom cam slots to the
top slots, so that a lower release box trips
before the boxes above it. Thus, in a salvo, the
lower bombs are released first, and so on in
order from bottom to the top of the racks.
This eliminates the danger of a bomb striking
a bomb installed below it. The lower vertical
slot allows full travel of the selector bar.
Selector bars are positioned by a bell crank
linkage operated by push-pull rods. A line of
push-pull rods along each side of the body
interconnects the bomb racks on each side. A
third line of push-pull rods are rigged in place
when the center racks are installed.
Push-pull rods are provided of the correct
length for each of the bomb rack arrange-
ments. They are bolted to a crank arm to which
the permanent rods are secured. The arms are
attached to the fuselage structure above the
wing front and rear spars. Permanent push-pull
rods are connected to an arm on a pulley drum
at their interlock mechanisms above the wing
on the sides of the body. (See Interlock illus-
tration.) The p'ulley drums are operated by
3/32-inch 7 x7 cables keyed to the drums. The
cables are also keyed in their grooves in the
three-groove pulley drum on the left side of
the coordinating unit. The three-groove pulley
ARMAMENT 5

RESTRICTED
drum normally turns with the single-groove
pulley drum which appears to be on the same
shaft. (See Coordinating Unit illustration.} The
single-groove pulley is connected to the pulley
drum on the bombardier's control stand by
1/8-inch 7 x 19 cables. The drum in turn is oper-
ated by the bomb release lever.
RIGGING: Detach all of the push-pull rods from
the bell cranks at the selector bars in the bomb
racks. Place the coordinating unit in the LOCK
position (same position which would lock the
release box SAFE). Rig the cables from the
coordinating unit to the permanent rod sys-
tem (pulley-drum on the interlock mechanism}
so that all of the permanent rod crank arms are
30 degrees (plus or minus 'h degree} forward
of neutral. Rig all of the rods to match the
outer end of the rack bell cranks with all selec-
tor bar cam slots bottomed in the LOCK posi-
tion.
Rig the cables from the coordinating unit to
the bombardier's stand so that the bomb
release handle is one-half inch short of its
LOCK notch when the selector bar cam slots
are bottomed in their LOCK position. Move
B-29 FAMILIARIZATI □ N
AND MAINTENANCE
the bomb release lever to SALVO-NORMAL
TEMPERATURE and return the lever to the
LOCK notch. Check to see that all of the
selector bars have bottomed. If any selector
bar has not bottomed, shorten the bell crank
length at this rack to make the selector bar
bottom, and readjust the push-pull rod to this
rack only.
Move the bomb control lever to SELECTIVE
r
and check that the selector bar is at its marked
SELECTIVE position (cam rollers are just enter-
ing the vertical part of the cam slots). Be sure
to check all of the racks. If all of the racks are
not at SELECTIVE, change the 'hinch "cushion"
of the bombardier's release lever, as it enters
its LOCK position, by adjusting the cables
between the coordinating unit and the stand.
The cushion is decreased to increase the travel
at the selector bars.
Check again at all bomb rack stations to see
that the selector bar cams bottom in their
LOCK position when the bomb release lever
is in the LOCK position. Again check to see
that all of the cam rollers are just entering the
vertical portion of the slots when the lever is
placed in the SELECTIVE position.
6 ARMAMENT

m
C)
:!I:
m
..
::0
:!I:: n
.. C)
:!I::
l"l"'I :z
:::z: ....
-I
:a
C)
,-
en
......
FORWARD BOMB BAY
INTERLOCK MECHANISM ----==
INTERLOCK CABLE TENSION
30 TO 50 POUNDS --------,
IDENTIFICATION COLORS
ON ACTUAL CABLES
CABLE B R B _ ..;;..
•. >- ~
BOMB RELEASE ~~- ~• ,.,,
SALVO /.."';--· ·•-?
.~<~ · ·~
-- -·' CABLE BR A ,d
~> .~ ~ BOMB RELEASE
LOCK
BOMB RELEASE SALVO CABLE
BOMB RELEASE LOCK CABLE
CABLE TO LOCK BOMB I
DOOR INTERLOCK
CABLE TO UNLOCK BOMB
DOOR INTERLOCK
CABLE SIZES:
BOMB CONTROL l4 INCH 7 BY 19 EXTRA FLEXIBLE
INTERLOCK ¥.37 INCH 7 BY 7
BOMB DOOR
SWITCH LEVER
BOMB RELEASE
CABLE TENSION
70 TO 90 POUNDS BOMB RACKS
CO-ORDINATING
UNIT---
REAR BOMB BAY
INTERLOCK MECHANISM
ex,
~
cc
)>'T)
z>
c:I
-
:Ir
)>-
- )>
z ;u
-i -
ITIN
z )>
)>-i
z-
n □
ITI Z

RESTRICTED B-29
FAMILIARIZATION
AND MAINTENANCE
COORDINATING UNIT
PURPOSE: To release the actuating screws from
the bomb doors for emergency bomb release,
and to utilize the same bomb rack mechanisms
for both emergency and normal mechanical
bomb release.
LOCATION: On top of the wing center section,
below the tunnel.
OPERATION: The coordinating unit consists of a
gear box containing a set of differential gears
and a set of intermittent gears. The actuating
controls of the coordinating unit are the bomb
release lever and the emergency bomb
release controls. (See EMERGENCY BOMB
CONTROL and BOMB CONTROL illustration.)
The actuating cables of the emergency bomb
release system are wound around a cable drum
at the forward end of the unit. Cables from the
bombardier's release lever are keyed to a
single-groove pulley drum on one side of the
unit. The cables which actuate the bomb rack
selector bar linkages are keyed to a three-
groove pulley drum which appears to be on
the same shaft as the single-groove pulley
drum. A cable drum with two single cables
keyed to it actuates the emergency bomb
door release system. (See EMERGENCY BOMB
DOOR RELEASE SYSTEM illustration.)
Under normal operation by the bomb release
lever, differential gear F will not turn: there-
fore, the differential housing (spider) shaft,
splined to the three-groove pulley drum,
rotates to actuate the selector bars. The bomb
doors will have been previously opened elec-
trically, in order to release the interlock
mechanism.
When any of the three emergency bomb
release controls is operated, the drum on the
forward end of the unit is rotated. This drum
rotates a train of intermittent (partial) gears
(A and E) connected with the emergency
bomb bay door release system so that the
initial rotation of the cable drum rotates the
door release drum winding the emergency
bomb bay door release system cables, to
release the actuating screw mechanisms from
the bomb doors. The intermittent gears con-
tinue to turn until the second pair (C and B)
of intermittent gears turn differential gear F,
rotating the differential housing shaft which
rotates the three-groove pulley drum actuat-
ing the selector bars to trip the release boxes
and salvo the bombs unarmed. During this
emergency release action, the internal shaft
carrying the bomb control pulley drum and its
differential gear is held stationary by the lock
on the bombardier's release lever.
After the doors and bombs have been
released by operation of the emergency con-
trols, the bombardier should reset the inter-
mittent gear train. This is done by turning the
wheel on the bombardier's stand in the direc-
tion opposite to which it was turned for
release.
MAINTENANCE: No maintenance other than
lubrication is required. (See HANDLING.) Do
not disassemble the unit unless it is absolutely
necessary.
8 ARMAMENl

m
c:::,
:I:
m
m
>
-<
C,
c:::,
c:::,
:a
en
>
:z
C,
m
c:::,
=-- :I:
::a
:I: m
=-- :a
:I:
,..., I'll
:::z:: r-
..... I'll
>
en
I'll
n
c:::,
c:::,
:a
C,
:z
>
....
-
:z
a,
C:
:z
-
....
(
EMERGENCY BOMBBAY DOOR RELEASE
SYSTEM CABLE DRUM--------'
EMERGENCY BOMBBAY D O O ~ R
RELEASE . .
SYSTEM CABLES
INTERMITTENT GEAR A JiJI
BOMB BAY DOOR RELEASE SYSTEM .
- - - ·DIRECTION OF MOTION TO OPEN
BOMB BAY DOORS
DIRECTION OF MOTION TO RELEASE
BOMBS
( (
'
---INTERMITTENT GEAR B CONTINUED MOTION
TRANSMITTED THROUGH DIFFERENTIAL GEAR F
, ~ -- THESE SHAFTS ARE NOT INTERCONNECTED
.---,-,,.,,,,..------------DIFFERENTIAL GEAR F
BOMB CONTROL
PULLEY
(LOCKED
POSITION)
BOMB RACK SELECTOR BAR
LINKAGE ACTUATING
CABLES
:l>"'I
z>
0 3:
3: r
~;
z~
-i -
111 N
z>
> -i
z-
□ D
111 Z

RESTRICTED 8-29 FAMILIARIZATION
AND MAINTENANCE
EMERGENCY BOMB RELEASE SYSTEM
PURPOSE: To open the bomb doors and release
all of the bombs in one operation.
OPERATION: The emergency bomb release sys-
tem can be operated from three different
locations-at the bombardier's station by
rotating the emergency bomb release and
reset wheel: at the pilot's station by pulling
the middle of the three pull handles on his
engine control stand: and in the aft pressurized
compartment by pulling a handle on the lower
left side of the station 646 pressure bulkhead.
Operation of any of these releases first dis-
connects the bomb door actuating screws
from the doors so that the doors may fall open.
When fully open, the doors release the
mechanical interlock system so that a further
pull on the emergency release will move the
selector bars to trip the release boxes, salvo-
ing the bombs unarmed.
If, after releasing the bombs by emergency
release, it is desired to close the bomb doors,
turn the bombardier's wheel in the direction
opposite to that for release. This resets the
coordinating unit. Next, the bomb door switch
lever must be placed in OPEN so that the
bomb door actuating screws will extend to
engage the doors. As soon as the gears have
extended fully, close the doors by placing the
switch lever in the CLOSE position.
The release and reset wheel drum in the bom-
bardier's stand turns the drum on the coordi-
nating unit by means of 3/32-inch 7 x 7 cables,
keyed to both drums.
The pilot's pull cable is secured to a traveler
block sliding on the drum actuating cable.
When the handle is pulled, _
the block bears up
against a ball stop swaged to the cable, pulling
the actuating cable and rotating the coordi-
nating unit drum. The traveler block is enclosed
in a phenolic tube for the entire length of its
travel, which is about 30 inches. When the
bombardier's wheel is reset, the traveler block
is returned and held by spring jaws, resetting
the release for future operation. This tube and
traveler block is located below the pilot's floor
on the left hand side.
The emergency bomb release in the .aft
compartment is connected to the actuating
cable in the same manner. Its traveler block
is under the left hand forward catwalk.
10 ARMAMENT

::=
- ,..,
z c.-,
--t
-I
::=
c-:,
ffl --t
,..,
::a c::,
r-
C,
C,
~
J:a
z
C,
ffl
==
:::lllo ffl
=i::,
::a
al:
:::lllo a,
:ii:
ffl
r"PI
::z: z
-t
C,
~
m
=
==
m
ca
C, "'-:I
c.c
=
z )> "11
z ►
-I
BOMB RELEASE oI
RESET CABLE Ir
::a :'.·>
INTERLOCK-CABLE-LOCKING z~
C , INTERLOCK-CABLE-UNLOCKING -i -
l'1 N
r-
z )>
)>-i
z-
en
- nD
- l'1 z

RESTRICTED B-29 FAMILIARIZATION
AND MAINTENANCE
INTERLOCK SYSTEM
PURPOSE: To pr~vent release of bombs unless
the bomb doors are fully open.
LOCATION: Two interlock mechanisms are
mounted one on each side of the fuselage
above the wing center section.
OPERATION: The left aft bomb door operates
the left interlock mechanism. The right forward
bomb door operates the right mechanism. A
short rod, attached to these doors, is pinned
to a pulley drum which turns when the door
moves. From the pulley drum, 3/32-inch 7 x 7
cables turn a vertical pulley drum on the inter-
lock mechanism. The cable is keyed to both
pulley drums. An arm, hinged at one end, is
operated by a pin in the vertical pulley working
in a slot in the arm. A locking pin extending
from the arm is inserted into or retracted from
a mating hole in a horizontally mounted pulley
drum. This drum moves the arm which actuates
the push-pull rods to the bomb rack selector
bars. It is keyed to cables actuated by the
coordinating unit.
The locking pin is not disengaged until the door
is open past vertical. Therefore, the selector
bars cannot be moved and the release boxes
are locked against either mechanical or elec-
trical release. A c·ompression spring around
the pin forces the pin out of the hole if the
actuating cables are severed.
EMERGENCY BOMB DOOR RELEASE SYSTEM
DESCRIPTION: This cable system releases the
bomb doors from their actuating screw mech-
anisms so that the doors will fall open. The door
release drum on the side of the coordinating.
unit winds two single cables (one for both right
hand doors and one for both left hand doors),
when an emergency bomb release is operated.
To each single cable are attached cables from
both doors, on the same side of the airplane.
Inside the door,·the cable is keved to a three-
groove drum from which cables lead to the
pulley drum on each of the two screw mech-
anisms attached to the bomb door. The pulley
drums at the ends of the screw mechanisms are
keyed to shafts with S shaped cams. Rotation
of the cams forces two locking bars from the
slots in the locking lugs attached to the retract-
ing screws releasing the screws from the doors.
(See illustration.)
12 ARMAMENT

RESTRICTED 8-29 FAMILIARIZATION
AND MAINTENANCE
BOMB DOOR DRIVE
PURPOSE: To drive the actuator screw mechan-
,
isms that open and close the bomb doors.
OPERATION: Forward and aft bomb door drive
systems are not mechanically interconnected.
However, when the bomb door switch lever is
operated, the bomb door motors for both the
forward and aft systems are energized at the
same time through their solenoid switches.
An actuator screw mechanism is provided at
each end of each bomb door. The upper ends
of the two actuators at one end of a bomb bay
are connected by universal joints to a Y drive
bevel gear box. Each Y drive gear box is driven
by worm-type reduction gears which, in turn,
are driven by torque tubes from 90-degree
bevel gear boxes mounted on the outboard
face of the web of the right hand catwalk at
each end of each bomb bay. The two bevel
gear boxes, for one bomb bay, are also con-
nected by torque tubes to the emergency
drive gear box.
The forward bomb door motor is mounted
under the front spar on the inboard face of the
right hand catwalk web. It drives the door
actuators by a bevel gear box inserted in the
drive between the aft worm gear box and the
90-degree gear box on the catwalk. The aft
bomb door drive system is identical with the
forward system except that the motor is under
the wing rear spar. The four actuators in each
bomb bay operate at the same time.
An emergency-drive gear box with a vertical
shaft flush with the catwalk is located midway
on the right-hand catwalk of each bomb bay.
The portable bomb door and wing-flap motor
can be engaged with this shaft. The portable
motor is secured to the catwalk by winghead
"dot" fasteners. (See Wing-Flap Drive illustra-
tion.) It is used to operate the bomb doors if
the bomb door motors are inoperative. The
portable motor is identical with the bomb door
motors except for the addition of its handle,
switch, and mounting flange.
Bomb door motors are similar in construction
to the landing gear motors. They consist of the
electrical motor itself, planetary reduction
gearing, a torque limiting slip clutch, and a
solenoid dog clutch. The torque limiting clutch
is set to slip with a torque of 750 (plus or minus
40) inch-pounds. The dog clutch is engaged
only when the motor is energized. Therefore,
when the portable motor is used, no drag will
be incurred from the normal bomb door motor
because its dog clutch will not be engaged.
Torque drive tubes are aluminum alloy with
universal joints between sections and at each
gear box connection.
A limit switch assembly, essentially the same
as the one used for the wing flap drive is
installed on the torque tube to the left of each
motor.
MAINTENANCE: No maintenance is required
other than replenishing the lubricant in the
gear boxes and in the leather boots around the
universal joints. (See Handling Section.)
ARMAMENT 13

l"l""I
:z:
---1
r-
-
-
....
en
=e
-
....
n
=
SPUR GEAR
BOMB DOOR
DRIVE TUBE
CONTINUES
THROUGH
WORM GEAR
TUBE
► "11
z ►
O I
Ir
~;
z ;o
-1-
1'1 N
z ►
► -I
z-
oO
l'1 z

RESTRICTED B-29 F"AMILIARIZATION
AND MAINTENANCE
BOMB DOOR LIMIT SWITCH
PURPOSE: To open the bomb door motor circuit
when the door actuating screws have reached
the limits of their travel.
LOCATION: On the drive torque tube between
the motor gear box and the adjacent Y drive
gear box. A limit switch assembly is provided
for each bomb door motor.
OPERATION: The limit switch assembly is essen-
tially the same as that used for the wing flaps.
The worm gear, mounted in the case in bronze
bearings, is bolted to the drive tube and drives
a spur gear. To each side of this spur gear, a
cam plate is secured° by three screws through
a cam retaining plate. The cams, through the
cam follower rollers, actuate the microswitch
pins. There is a switch for each cam: one being
actuated when the bomb doors have fully
opened, and one when they have fully closed.
ADJUSTMENT: The cams were pre-set at the
factory but they may be readjusted if neces-
sary Before the bolt is inserted through the
worm gear tube and the drive tube, torn the
drive tube to a dead stop with the bomb doors
fully closed. Then back off the torque tube
one and one-third turns to allow for coast. An
adapter, provided in the crew chief's kit, is in-
serted in the emergency drive shaft on the cat-
walk to aid in this adjustment.
Turn the worm tube in the same direction as
for closing the doors until the switch clicks off.
Insert the bolt through the worm tube and the
torque tube. To do this, it may be necessary
to turn the worm tube slightly but it is impor-
,
tan+ not to exceed one-eighth turn in either
direction.
If it is necessary to re-set the "opening" cam,
turn the hand crank until the doors are fully
opened, then turn back the drive tube two and
two-thirds turns. Loosen the "opening" cam
retainer screws and turn the cam until the
switch just clicks off. Then the retainer screws
are retightened and resafetied.
After adjusting the limit switc~, run the bomb
doors through several cycles to be certain that
the motor circuits break at the proper time.
ARMAMENT 15

RESTRICTED
NUT DRIVE
TUBE
FULLY EXTENDED
POSITION OF TUBE
ACTUATING SCREW LUG----
NOTE
ACTUATING
SCREW
ACTUATING
NUT
FLUID
CHAMBER
NUT
STOP LUG
HOUSING AND SHAFT
BROKEN AWAY TO SHOW
FULLY EXTENDED POSITION
8-29 FAMILIARIZATION
AND MAINTENANCE
EMERGENCY RELEASE
PULLEY
GUIDE
STOP
LUG
PULLEY
SPRING
TORSION
SPRINGS
BRONZE
BUSHING
LUG (DOOR
CONNECTION)
BOMB BAY AND NACELLE DOOR
OPERATING MECHANISM
IDENTICAL, EXCEPT IN LENGTH
FOR BOMB BAY DOORS-21 INCHES
FOR NACELLE DOORS-19 INCHES
RELEASED POSITION
OF ROLLER DOGS
r~--EMERGENCY RELEASE CABLE
(PULLED)
BOMB BAY DOOR ACTUATOR
PURPOSE: To open and close the bomb and
nacelle doors.
LOCATION: An actuator is located at each end
of each bomb door and at the forward end of
each nacelle door.
GENERAL DESCRIPTION: Bomb door actuators
are similar to nacelle door actuators except
that bomb door actuators are two inches
longer.
16 ARMAMENT

RESTRICTED
The nutdrive tube is driven by the Y gear box
and holds the bronze nut. The nut is screwed
into a steel retainer secured to the inside of
the tube by four bolts. These bolts also hold
the thrust bearing stop-flange on the outside
of the tube. The thrust bearing prevents bind-
ing, when the stop flange is in contact with the
stop at the upper end of the housing after
emergency door release. The nut retainer has
stop lugs at each end which engage lugs on
stop flanges bolted to the ends of the screw.
These prevent the nut from turning off the
screw if the limit switches fail to stop the door
motor.
The nut and screw have four right hand Acme
threads per inch. The upper end of the steel
screw is supported in the nut drive tube by its
upper stop-flange leaving the drive tube free
to turn. Screwed into the lower end of the
screw assembly is a locking lug, which is nor-
mally held by two rollers fitting into notches in
the lug. This lug is the screw's only connection
to the housing and the door. Torsion springs
force the rollers into the notches in the locking
lug. The roller axles are supported in slots in a
fitting secured to the housing and thus to the
door.
Two U-shaped castings, bolted to the lower
end of the screw, bear against the housing and
prevent the screw from turning with respect to
the housing.
Two guides on the upper end of the aluminum
alloy housing are spaced far enough apart to
prevent chattering and binding of the nut tube
when it is extended. The guides have an inter-
nal slot, holding a hard felt ring which acts as a
bearing surface against the nut drive tube.
The lower of these guides acts as a stop to
prevent the nut drive tube from slipping out
of the housing during emergency door release.
It then bears against the thrust bearing stop
around the outside of the nut drive tube.
The lower end of the housing holds the release
mechanism and the locking lug which connects
the screw to the door. The release mechanism
consists of a pulley drum keyed to a shaft with
8-29 FAMILIARIZATION
AND MAINTENANCE
two S shaped cams. When the pulley drum is
turned by operation of the emergency relP-ase
controls, the cams force the rollers out of the
notches in the screw locking lug. The screw and
the nut are then free of both the housing and
the door so that the door can drop open.
A torsion spring at the pulley drum helps to
place an initial tension on the operating cable.
Stops are cast on the inner side of the pulley
drum, one of which strikes a stop plate riveted
to the housing, to limit the pulley drum rotation
to about 90 degrees.
Movement of the doors at emergency release
is dampened by hydraulic fluid torced through
a 3/32-inch diameter hole in a piston sliding
within the inner bore of the screw. The piston
has a split cast iron piston ring and is secured
to the housing assembly by a piston rod which
passes through a seal at the lower end of the
screw When the actuator is in its compressed
condition and is standing vertically, the fluid
level should just cover the top of the piston.
The actuator is secured to the door by an
adjustable universal type fitting.
MAINTENANCE: If fluid leaks from the damping
cylinder, the actuator must be removed and
disassembled. The piston must be removed
from the piston rod so the rod can be slipped
out of its lower guide and the "O" section seal-
ing ring (AN6227-8) replaced in the guide.
When the piston rod is replaced, care must be
taken not to damage the new sealing ring.
Instructions for servicing the damping cylinder
with fluid are given on a decal on each actu-
ator: With piston extended and actuator in
vertical position (door end down), remove the
1/4-inch pipe plug in the upper end of the screw
and fill the cylinder to within 4.4 (plus or minus
0.1) inches of the upper end of the screw with
hydraulic fluid, Specification AN-VV-0-366a
(red color). Replace pipe plug and return
piston to compressed position.
A thin coat of light oil on the nut drive tube
prevents binding and chattering of the unit.
ARMAMENT 17

RESTRICTED
LEGEND
rrm COIL
➔=~ CONNECTOR
--<=J- SPLICE
-a:rf.p:D- FUSE
---0- MOTOR
:flffi, SOLENOID
..0.. OHMS
,----~L -Pl 19
I I
FORWARD<....----
: "--+-BOMB DOOR FUSE
l J (2 AMP.)
'- - - -,BOMBARDIER'S
FUSE PANEL
BOMB DOOR
8-29
F"AMILIARIZATION
AND MAINTENANCE
11 11 SWITCHES LIMIT SWITCH
l1 ,
9:Q~...J MD J_, MD
._____ p126---+-+----'
18
MD82+~MD88--➔. ~MD2l 388-foW10
MD87 l~-~-) MD89~ ~MD381 ~MD11
(
OPEN MD 387 AFT BOMB DOOR
P-120
LEFT HAND TUNNEYNl-lL-- MOTOR SOLENOID SHIELD.
BOMBARDIER'S PLUG POSITl9N 4 MD4+----''._-
__
SP_L_IC_EMDB~', MD389
CONTROL MD14......n...---MD9----!.-o
O
I MD390---
~AND ~--J
LuMIT sw1TCH
BOMB DOOR CONTROL CIRCUIT
Both the forward and aft bomb door motors
are energized simultaneously through solen-
oid switches controlled by the bomb door
switches in the bombardier's control stand. The
bomb door limit switches break the control
circuits at the limits of door travel.
These motors are reversible and have two sets
of series-wound field coils, one set for each
direction of rotation. When either field and
the armature are energized, the motor clutch
solenoid is also energized, engaging the dog
clutch with the output shaft.
Control circuits for opening and closing the
bomb doors are independent of each other.
Power for both control circuits is taken through
a single 10-ampere fuse in the fuse panel above
the bombardier's panel. From the fuse, the
wires run to the switches operated by the bom-
bardier's door control lever. The CLOSE con-
trol circuit wire joins with two wires. Each of
these two wires connects to its motor solenoid
switch through its CLOSE limit switch. The cir-
cuit for opening the bomb doors is similarly
wired. The motor solenoid switches are
located in shields near the bomb doors. When
either solenoid switch is energized, it makes
contact between a 24-volt direct current
power bus and the motor. The motor circuits
are not fused.
ARMAMENT

a,
c::,
:i:
m
c:,
=-- c::,
=al z
a: -I
=--
a: :a
...., c:::,
::z::
--1 r-
c:,
-
:a
c:,
C:
-
-I
-
co
B
-3 INTERVAL RELEASE l
DETAIL OF
TIMING CIRCUIT
(NOT SHOWN)
- -,
I
I
I
C
_ _ _ _ _ _ _ _ _ _ _J
RS-2 RACK SELECTOR RELAYS~
(
- BOMBSIGHT RELEASE SWITCH -r~ 7
{ P.D. I . < ' - - - - . I
GLIDE BOMB RECEPTACLE
t
r-7
(
ON BOMBARDIER'S
CONTROL PANEL t
/ ' . ~----11..J._----,
'- / ._ -,- - _/',._ - - ....A..J
- _J b 7 13 15
BOMBSl?HT STABILIZER . TI t '
I I
L-A...J ,----.
I 15 AMP. I
24 V. I
D. C. I
I
- - - - - RELEASE CONTROL CIRCUIT
- - - - - GROUP SELECTOR CONTROL CIRCUIT
RELEASE IMPULSE CIRCUIT
I ' NEXT IMPULSE GOES TO
I NEXT COCKED A-2 RELEASE BOX
F::~~f::~ET : _r;AX-5 ~X-~ox
___-
7
L I I ·-• -t f---1 4 D -=- t - A-2
r _ J I .- 1 _
f,-_ I RELEASE BOX
FRONT BOMB BAY TANK I> D > I ==~ 'L I
SAFETY SWITCH ' BOMB
,_iO - 8~~-L~-t= COCKE;O~T;N~ I
-, > C~ · ,· TO PIN A FRONT LEFT RACK PLUG
" TO PIN A RE:AR LEFT RACK PLUG
TO PIN A REAR RIGHT RACK PLUG
cc,
~
c=
), "'1
z),
oI
-
Ir
), -
- ),
z ;o
-i -
rriN
z),
),-l
z-
nD
rri z

RESTRICTED 8-29 FAMILIARIZATION
AND MAINTENANCE
BOMB CONTROL CIRCUIT
GENERAL DESCRIPTION: Be fore re Ie a s i n g
bombs electrically, the bombardier must:
Open the bomb doors: place the bomb release
lever in SELECTIVE to unlock the mechanical
safety in each of the A-2 release boxes: turn
at least one bomb group selector switch to the
ON position: and at least one minute prior to
releasing the bombs, pre-set the bomb inter-
val release control unit.
Opening the bomb doors closes the four bomb
door safety switches, one of which is located
at the forward end of each bomb door. The
switches are connected in series and close
the circuit between the two-ampere (BOMB
SAFETY) fuse in the aft bomb door motor
solenoid shield, and the bomb group selector
switches on the bombardier's control panel.
Each of the four bomb group selector switches
and the solenoid of the bomb safety relay are
energized from this fuse through the safety
switches. When so energized, the relay closes
the supply circuit to the bombsight release
switch, the manual release switch, the time-
delay relay, the bomb release formation light,
and the bombardier's bomb door signal light,
from the IS-ampere (BOMB RELAY) fuse in
the fuse panel above the bombardier's control
panel. The power supply of-the bomb interval
control is connected to the same IS-ampere
fuse. Power for the glide bomb attachment
and the bombsight is taken from another IS-
ampere (BOMBSIGHT) fuse in the same
panel.
The manual bomb release switch is a momen-
tary contact double-pole switch with a central
OFF position. Flipping the switch handle in
either direction initiates an impulse from the
bomb interval control unit. A hinged guard
prevents accidental release.
The bomb interval control unit delivers
momentary impulses to the rack selector relay.
It may be set for SELECT or TRAIN by means
of a toggle switch. In SELECT, the bomb inter-
val control unit transmits a single electrical
impulse to rack selector relays each time the
circuit is closed through the bombsight, or
through the manual release switch. In TRAIN,
a predetermined number of timed electrical
impulses are transmitted from the unit when
electrical contact is made by the bombsight
or the manual release switch. These impulses
are directed by the two rack selector relays
to the four bomb group circuits in sequence;
provided the rack selector relays are ener-
gized by closing the bomb group selector
20 ARMAMENT

RESTRICTED
switches. Current for the relays is supplied
from the two-ampere (BOMB SAFETY) fuse in
the aft bomb door relay shield through the
bomb door safety switches.
No current can flow in any electrical circuit
unless a return path is present to complete the
circuit. In the release circuits, the return path
for release impulses is through the airplane
structure {ground). As will be seen, the only
available path to ground is through a cocked
A-2 release box. When all the release boxes
in a given bomb group circuit have been
f
tripped, no path to ground exists for the
next impulse to follow. The rack selector relays
are so designed that under this condition the
set of relays controlling that particular bomb
group circuit will automatically transfer the
release impulse to the next set of relays having
a ground return through a cocked release box,
to prevent idle or dead impulses in the bomb
train.
From the rack selector relays, the impulse
travels to the first of the beginning sequence
bomb group rack receptacles into which the
rack connector is plugged. The release impulse
then enters the AX-5 auxiliary box at the lowest
bomb station on the rack. If an A-2 release box
is installed but is not cocked, the impulse con-
B-29 F'AMILIARIZATl □ N
AND MAINTENANCE
tinues through the A-2 release to the AX-5 box
next higher where, if there is no A-2 release
box installed, the impulse will again be trans-
ferred to the next higher AX-5 box. If at this
station, an A-2 release box is installed and is
cocked, the impulse grounds through the sole-
noid coil of the cocked A-2 release box. The
solenoid is thereby energized and trips the
spring-loaded release box mechanism to actu-
ate the bomb shackle and thus release the
bomb.
When the release box has been tripped and
the impulse has ceased, contacts within the
box make a new connection which transfers the
next impulse of that bomb group circuit to the
next cocked A-2 release box.
From the description given, it is seen that an
impulse passes in order through the AX-5
auxiliary boxes, or through uncocked A-2
release boxes, until it enters a cocked A-2
release box, for only in a cocked release box
may it find a path to ground. Should any
cocked A-2 release box fail to operate
because of internal failure, or jamming of the
bomb shackle engaged with it, the impulses
entering the box will continue to ground
through the solenoid coil attempting to trip
ARMAMENT 21

RESTRICTED
the release box. The impulses are transferred
by a release box only after it has tripped and
so cannot reach the next station above on the
rack. This prevents the dropping of any more
bombs in the group controlled by the corre-
sponding rack selector relay and in this way
eliminates any possibility of a bomb being
dropped upon another because of release
failure.
AUXILIARY FUEL TANK SAFETY SWITCHES:
When auxiliary fuel tanks are installed in a
bomb bay, the tank safety switch in that bay
must be placed in the OFF position. This opens
the bomb group circuits of that bay so the
tanks cannot be dropped by accident.
The switch for the forward bomb bay is located
on the left hand forward side near the top of
the bomb bay. The switch for the aft bomb bay
is in a corresponding location aft of the wing
rear spar.
SIGNAL LIGHTS: A red signal light on the bom-
bardier's panel is lit when the bomb doors are
open. An amber colored indicator light on the
pilot's instrument panel flashes with each
bomb release impulse as the bombs are
dropped.
To indicate to airplanes following in formation
when bombs are to be dropped, a bomb
release formation light shows to the rear. The
B-29 FAMILIARIZATION
AND MAINTENANCE
light illuminates white while the bomb doors
are open. When the first bomb is released, the
light flashes red. Through the action of the
time-delay relay, the red color shows for
approximately five seconds after the last
bomb in the train has been released.
BOMBSIGHT: The M-7 bombsight is essentially a
computing mechanism which, as the airplane
approaches the target, predetermines the
instant bombs are to be released. After suit-
able corrections have been made and the
bombsight is tracking the target, the release
switch in the bombsight is automatically closed
at the predetermined instant. To insure a
steady bombing platform, and to allow the
bombardier to guide the airplane to track the
target on the bombing run, the bombsight is
mounted on and operates in conjunction with,
the directional stabilizer of the autopilot. The .
use of the autopilot in combination with this
bombsight makes possible bombing of a high
order of precision.
Directional movements of the bombsight rela-
tive to its mount are transmitted to the pilot's
indicator (PDI) on his instrument panel. When
the autopilot is not being used, the PDI
indicates to the pilot the direction in which
to turn the airplane to track the target.
22 ARMAMENT

RESTRICTED
PART No.
RS-2
MALLORY
COIL
NOTE COVER
REMOVED
8-29
COIL
FAMILIARIZATION
AND MAINTENANCE
· CONNECTOR
j
RS-2 RACK SELECTOR RELAY
RS-2 RACK SELECTOR RELAYS
PURPOSE: To distribute the electrical impulses
from the bomb interval control unit among the
four bomb group circuits so that the bombs
will be dropped in sequence causing a mini-
mum unbalance. Also, the relays permit the
omission of any bomb group or groups from
the release sequence without omissions from
the train when the remaining bombs are being
dropped.
LOCATION: Two RS-2 units are mounted to the
left of the bombardier's feet on the lower side
of the fuselage.
GENERAL DESCRIPTION: Each RS-2 rack selec-
tor unit contains two pairs of relays, each pair
controlling one bomb group release circuit.
ARMAMENT 23

RESTRICTED
The relays of both rack selector units are so
connected that the sequence of release
impulses will be I, 11, Ill, IV, I, II, Ill, IV, etc., when
the two pairs of relays in each RS-2 unit are
designated I and II in the first unit, and Ill and
IV in the second unit. This sequence will con-
tinue until the number of bombs dropped com-
pletes the number set on the bomb interval
control, or until there are no more cocked A-2
release boxes in the bomb group circuits. If the
sequence of the train release should end on
Ill, for example, the sequence will resume with
IV when bombs are again released, unless all
of the bomb group selector switches have
been turned OFF and then returned to the ON
position, or if the bomb doors have been
closed before the next series of releases. If
either has occurred, the sequence will again
start at I.
Bomb racks are wired so that the lowest sta-
tions release first and so on up the rack as the
release sequence progresses to each of the
four bomb group circuits. For all sizes of bombs
loaded, the first bomb released is from the
lowest loaded station in the front right bomb
group in the forward bomb bay. The next bomb
for all but the 500-pound bomb racks is
released from the lowest loaded station in the
rear right bomb group in the aft bomb bay,
and so on. This "layer" release, alternating
from the forward and aft bomb bays, is not
B-29
FAMILIARIZATION
AND MAINTENANCE
always possible since the loading of different
size bombs, the installation of auxiliary fuel
tanks in a bomb bay, etc., alters the sequence
of transfer from one rack to another. (See
BOMB RELEASE SEQUENCE.)
Rack selector relays are so wired that bomb
groups may be omitted from the release train
without skipping an impulse or having dead
spaces in the train. This transfer feature allows
a bomb loading by which a limited selection
of type of bomb can be used against targets
of opportunity. It also automatically prevents
dead impulses in a train if the release circuit is
open in a bomb group. When an open circuit
occurs in a bomb group, the RS-2 relays trans-
fer the release impulses intended for the faulty
circuit to the next bomb group circuit in which
there is a cocked release box.·
Before the first bombs are released, all four
of the bomb group selector switches should
be flipped to the OFF position, then, to the ON
position. This insures that the release sequence
will start with the correct {I relay) station. This
can also be accomplished by opening and clos-
ing the bomb doors.
OPERATION: Each of the two RS-2 relay pairs
controls two bomb group circuits. These pairs
are indicated on the diagram as I and II in one
RS-2 unit, and Ill and IV in the other RS-2 unit.
ARMAMENT

RESTRICTED
The current through the bomb group selector
switches, from the two-ampere fuse in the aft
bomb door solenoid shield, is indicated on the
diagram in green; the release impulse from the
bomb interval control unit is indicated in red.
FIGURE 1: When all four bomb group selector
switches on the bombardier's control panel
are flipped to the ON position, control current
(green) passes through relay pairs I. 11, Ill, and
IV, energizing coils 17, 18, 19, and 20 in each.
The magnetic flux thus created by the current
flow through the coils closes relay switches 11,
12, 13, 14, I5, and 14 in each unit. The control
current is grounded through the solenoid coil
of the first cocked A-2 release box in each
bomb group circuit. The control current is too
small to energize the release box solenoid suffi-
ciently to trip the mechanism.
FIGURE 2: The bomb release impulse (red) from
the bomb interval control enters through ter-
minal D to switches 12 and 14 in relay pair I.
The major portion of the impulse current goes
through switch 12 and the low resistance coil
20 (.234 ohms) then out terminal Bto the first
cocked release box in the front right bomb
group, where it energizes the release box sole-
noid to trip the release mechanism.
A small portion due to the relative coil resist-
ances of the impulse current finds a path to
8-29 FAMILIARIZATION
AND MAINTENANCE
ground through switch 14 and coil 6, energizing
coil 6 to close switch 3. This action opens.switch
4 and establishes a new path for the control
current (green) through coil 8 which then holds
switch 3 closed after the impulse has ceased.
The control current grounds through switch 15
in relay pair II, and through switch 16 in relay
pair I, as long as the impulse current holds
switches 12, 14, and 16 down by the magnetic
flux it creates by passing through coil 20. Relay
pairs 11, 111, and IV are not affected by the first
impulse.
FIGURE 3: This figure shows the condition exist-
ing in pairs I and II in the interim between the
first and second release impulses. Pairs Ill and
IV are not shown as they are unaffected and
remain as shown in figure I. Coils 18 and 20 of
relay pair I are no longer energized; therefore,
switches 14 and 16 are open and switch 12 has
closed the circuit through contact I0.
FIGURE 4: The second impulse from the bomb
interval control enters through terminal D of
first unit (I and 11) and goes through switch 12
to contact IO in pair I. From here the impulse
progresses to switches 11 and 13 of relay pair
II. The major portion of the impulse current
goes through coil 19 from switch 11 to the first
cocked release box in the rear left bomb group
circuit, energizing its solenoid to trip the
release mechanism. A small portion of the
ARMAMENT 25

RESTRICTED
NOTES
B- 29
FAMILIARIZATION
AND MAINTENANCE

RESTRICTED
NOTES

RESTRICTED
I
C A H
FIGURE No. 5
BETWEEN SECOND AND THIRD IMPULSE CONTROL CURRENT
FINDS GROUND IN Ill AND IV
B D
--i10
~ -
--
~r
i
~
:c:-1
~--------1
.~ ~I
I_,_
,;~i
~;
r-i- ~·
B E D
,____-=.-::.::.+::.==y
===:- TO
• ;;, µ-~- A~~
~ ·~ Ill
~., ~
~~v
-!~l
BOMB RELAY FUSE (15 AMP.) LOCATED IN BOMBARDIER'S FUSE PANEL
FIGURE No. '2
FIRST IMPULSE TRIPS FIRST RELEASE BOX IN FRONT
RIGHT BOMB GROUP
!
+2::tC
A
flJSE ·
.
l
FIGURE No. 6
THIRD IMPULSE PATH IS THROUGH I AND II TO Ill TO TRIP
FIRST RELEASE BOX IN FRONT LEFT BOMB GROUP
FIGURE No. 3
BETWEEN~ FIRST AND SECOND IMPULSE
C A H B D
FIGURE No. 7
BETWEEN THIRD AND FOURTH IMPULSE
OPERATION OF RS-2 RACK SELECTOR RELAYS
ARMAMENT
FIGURE No. 4
SECOND IMPULSE TRIPS FIRST RELEASE BOX
IN REAR LEFT BOMB GROUP
---- -~ 10
--.-+--+-::~
+-· (
fR()M)-._,0
n ;
•ND ~ "
I ( ,-
II = +24V
FIGURE No. 8
FOURTH IMPULSE TRIPS FIRST RELEASE
BOX IN REAR RIGHT BOMB GROUP RELAYS THEN
RE TURN TO POSITIONS SHOWN IN FIGURE No. 1
21

B- 29
NOTES
F'AMILIARIZATICN
AND MAINTENANCE

RESTRICTED
impulse current grounds through switch 13 and
relay coil 5, energizing coil 5 to close switch 2.
This also breaks the contact at switch I and
establishes a new path to ground for the con-
trol current (green) of relay pair II energizing
coil 7 and holding switch 2 closed when the
impulse stops.
Switches 11, 13, and 15 are held down by the
magnetic flux created by the release impulse
passing through coil 19. When the impulse is
completed, switches 13 and 15 open and
switch 11 contacts at 9.
FIGURE 5: As soon as the second impulse stops,
the control current for unit I and II finds a
ground at switches 15 and 16 in the next RS-2
relay unit containing relay pairs Ill and IV. In
unit I and II, coils 17, 18, 19, and 20 are no
longer energized sothatswitches 13, 14, 15, and
16 in that unit will open. Switches 11 and 12
make contact at 9 and IO respectively, pro-
viding a path for the third release impulse
through terminal H of unit I and II to unit Ill
and IV.
FIGURE 6: As noted above, the third bomb
release impulse enters the first RS-2 relay unit
through terminal D. It then passes from ter-
minal H of the first RS-2 unit to terminal D of
the second RS-2 unit.
The action will now be the same as in figure I,
except that the solenoid energized by the
bomb release impulse will be in the first cocked
release box of the front left bomb group cir-
cuit.
8-29 FAMILIARIZATION
AND MAINTENANCE
FIGURE 7: Relay pairs Ill and IV will be in the same
condition as that shown for I and II in figure 3.
FIGURE 8: The fourth impulse from the bomb
interval control will release the bomb con-
trolled by the first cocked release box in the
rear right bomb group circuit in the same
manner as that explained in figure 4.
After the completion of the fourth impulse in
the series, all of the relays return to the con-
dition ready for the next series of impulses in
the train as shown in figure I because no fur-
ther grounds {switches 15 and 16 in each unit)
exist within the relay units for the control cur-
rent to maintain a holding magnetic flux for
switches 2 or 3. When these switches open,
contact at switches I and 4 is re-established
and the control current again seeks a ground
through the first cocked release box in each
of the bomb group circuits. This continues until
all of the bombs in the train are released.
Reference to the diagram will make clear the
sequence of events occurring when one or
more bomb group selector switches are
open. The same will occur when there are
open circuited release boxes in the group cir-
cuits.
MAINTENANCE: No repair of the rack selector
relays beyond removing the cover to blow
dust from the contact points should be
attempted. If such cleaning of the contact
points does not correct erratic operation,
replace the unit. Do not lubricate the relays
or bend the leaf springs of the contacts, as the
tensions of these springs have been carefully
set for correct operation.
ARMAMENT 29

RESTRICTED 8-29 FAMILIARIZATION
AND MAINTENANCE
BOMB INTERVAL RELEASE CONTROL UNIT (INTERVALOMETER)
PURPOSE: To time the bomb release impulses to
obtain a desired ground spacing of a train of
bomb bursts, and to govern the number of
bombs to be dropped in a train release.
LOCATlON: On the left hand side of the bom-
bardier's control panel.
OPERATION: Electrical impulses originating in
this unit are delivered to the rack selector
relays. These impulses are timed electronically
through the interaction of two type BR I05050
or RCA 2050 gas thyratrons and capacitators
in the unit. The desired timing, or ground spac-
ing of bursts, is set into the unit by means of
a dial on the face. This dial is calibrated in terms
of the ground speed of the airplane in relation
to the desired ground spacing of the bombs.
The desired number of bombs to be dropped
in train release is set on a counter dial on the
face of the unit. As each bomb is released, the
counter drops back one division until all of the
bombs in the train have been released.
A toggle switch in the lower forward corner
momentarily closed. When the toggle switch
is in the TRAIN position, and the bombsight or
manual release switch is closed, bombs drop
to the number pre-set on the counter dial, and
are spaced as pre-set on the ground spacing
dial without further action by the bombsight
switch or the manual release switch. The unit
is turned on by setting the switch to SELECT
or setting the switch to TRAIN and moving the
counter to any desired position above zero.
It should be turned on at least one minute
before bomb release to allow the vacuum
tubes to warm up.
.A red pilot light, next to the toggle switch,
lights when the unit is on and the jewel rim is in
the ON position.
The illumination of the pilot light may be varied
or extinguished by turning the jewel rim. The
unit may be shut off by flipping the switch to
the TRAIN position and setting the counter to
zero. The unit should be left OFF when it is not
to be used.
of the unit has two positions, - SELECT and MAINTENANCE: If one of the thyratron tubes
TRAIN. When the switch is in the SELECT posi- fails, replace it with a properly aged and tested
+ion, one bomb is released each time the tube. Replace the unit if poor operation is
bombsight switch or manual release switch is experienced.
30 ARMAMENT

RESTRICTED 8-29 F"AMILIARIZATIDN
AND MAINTENANCE
BOMB INTERVAL CONTROL UNIT
TIMING ADJUSTMENT: Check the interval tim- variable calibrating resistor. This is a screw
ing by setting the switch on TRAIN, the coun- adjustment and is accessible by taking the unit
+er at 50, and the interval dial at 750 feet at 500 from the panel and removing the back cover
miles per hour. Close the manual release plate. The adjustment screw is the one to the
switch and time the period required for 50 aft end of the unit as it is installed in the air-
•
release impulses: in other words, the time plane. Turning the screw clockwise decreases
required for the counter to click back to zero. the time: turning it counter-clockwise increases
The time should be between 45 and 55 seconds. the time required under the conditions out-
If the time is not within this range, adjust the lined above.
ARMAMENT 31

RESTRICTED B-29 FAMILIARIZATION
AND MAINTENANCE
SAFETY STOP NUT
ON ARMATURE--
---RELEASE LEVER (COCKED)
- - - - - RELEASE LEVER ASSEMBLY
---ARMING LEVER (TRIPPED)
- - - RELEASE LEVER (TRIPPED)
CONTACT
CAM
DOWEL
PIN
MECHANICAL ACTUATOR----
ARMING
LEVER ASSEMBLY
BUMPER PLATE
A-2 BOMB RELEASE
ELECTRIC
CONNECTOR
PURPOSE: To operate the bomb release and arm- LOCATION: An A-2 release box must be installed
ing levers of the bomb shackle by means of a at each loaded bomb station on the shackle
cocked spring mechanism, tripped electrically. side of the racks.
The release mechanism may also be tripped GENERAL DESCRIPTION: The A-2 release box is
mechanically, and in this case only the bomb an electrically-operated mechanical device
release lever of the shackle is operated. which arms the bombs and releases them
32 ARMAMENT

RESTRICTED
from their racks by actuating the bomb
shackle levers. Through operation of the salvo
couplings (actuator crank) by the rack selec-
tor bars, the release boxes may be locked or
placed in condition for electrical release or
for mechanical salvo of the bombs unarmed.
The release mechanism is mounted in a pressed
steel, dust-tight housing. Two movable arms
are mounted on the front of the housing; one
for operating the arming lever of the shackle1
and one for operating the release lever of the
shackle. For emergency use, the release arm
has a hinged ear permitting release of the
bomb by prying over the shackle release lever
with a screw driver or similar tool if other
release methods fail.
For manually tripping the release, a small stud
with a screw driver slot is provided on the front
of the case. Use of this release method causes
the bomb to be dropped armed, and the inter-
nal transfer switch to direct future release im-
pulses to the next cocked release box above
on the rack. This release method is useful in
case a faulty release box prevents electrical
release of bombs from the remaining stations
on the rack.
The tongued salvo coupling is located on the
back of the case. When the release box is
installed, this coupling mates with the slot on
8-29 F'AMILIARIZATION
AND MAINTENANCE
the rack lever arm which is rotated by the cam
slot in the selector bar. (See page 35). The
selector bar, in turn, is operated by the bomb
control cable system.
A three-pronged electrical plug, located in
a corner of each A-2 release box, fits into the
receptacle of the AX-5 auxiliary release box.
Two dowel pins in the other two corners help to
locate the release box on the bomb rack. Two
snap fasteners secure the release box to the
bomb rack.
The release boxes are marked FRONT at their
forward ends. A right hand box cannot be
installed on a left hand rack.
OPERATION: To cock the A-2 release box, the
arms must be pulled outward with the arming
arm slightly in advance of the release arm.
Inside the case, the arming arm latch engages
the catch of the arming arm assembly. As the
arming arm assembly is raised, the release arm
latch is pulled into position and hooked under
the release arm catch.
When the arms are cocked, the contact lever
of the transfer switch breaks the connection
between contact B and contact A and makes
a new connection between contact Band con-
tact C which then completes the release circuit
to ground through the sol_
enoid coil, when an
impulse energizes the solenoid. This causes
ARMAMENT 33

RESTRICTED
the movable core of the solenoid to withdraw
the arming arm latch, tripping the arming arm
assembly. Near the end of travel of the arm-
ing arm, a pin in the arm assembly contacts the
release arm latch, tripping the release arm
assembly. This causes the release arm to actu-
ate the bomb shackle release mechanism,
releasing the bomb.
When the electrical release impulse ceases,
the solenoid core returns under spring pres-
sure to its normal position. The transfer sw~tch1
actuated by movement of the release arm,
breaks the circuit between contact Band con-
tact C, and establishes connection between
contact B and contact A. This transfers the
release circuit to ground in the next cocked
release box above in the rack.
When the bomb release lever in the bombar-
dier's control stand is placed in SALVO posi- ,
+ion, the bomb rack selector bars rise, causing
the small crank arms in the racks to rotate each
of the salvo couplings of the release boxes. A
pin in the end of the salvo lever inside the box
engages the release arm latch, tripping only
the spring-loaded release arm. The arming arm
remains in its cocked position and, therefore,
the shackle releases the fuse arming wire and
the bomb drops unarmed.
When the bomb release lever is placed in the
LOCK position, the salvo couplings are rotated
8-29 F"AMILIARIZATION
AND MAINTENANCE
in each release box, forcing the pin in the end
of the salvo lever against a leg of the release
arm latch, preventing the release arm assem-
bly from tripping. Also, when the salvo cou-
pling is turned in its LOCK direction, a notch
in the salvo lever is turned out of register with
the safety stop nut, preventing the solenoid
core from moving. This locks the arming arm
latch, preventing the arming arm from being
tripped. Thus, when the bombardier's bomb
release lever is in the LOCK position, the
release box cannot be tripped either manually
or electrically.
INSTALLATION: Before installing the release
boxes on the bomb racks, set the bomb release
lever at the SELECT position. Then set the
tongues on the salvo couplings of the release
boxes to approximately vertical so they will
slip into the slots in the selector bar crank arms.
Mate the dowel pins in the holes in the rack;
then push the release box against the rack. The
snap fasteners should lock. If the plunger in the
fastener does not snap flush, use a pencil or
screw driver on the plunger allowing the wings
of the fastener to snap out. With the point of
a screw driver inserted between the rack and
the release box, pry slightly to make sure that
the fasteners are holding properly.
34 ARMAMENT

RESTRICTED
SALVO POSITtON
B-29 FAMILIARIZATION
AND MAINTENANCE
SELECTIVE POSITION
MECHANICAL
ACTUATOR
CRANK
ARM
CAM
SLOT
LOCKED POSITION
- , LENGTH OF THIS PORTION VAR-
.____r--IES FROM BOTTOM TO TOP OF
- SELECTOR BAR SO THAT THE
LOWEST BOMB RELEASES BEFORE
NEXT BOMB ABOVE AND SO ON
UP THE RACK.
RELEASE UNIT ACTUATOR
When the A-2 release box is installed, a short-
ing switch in the AX-5 auxiliary box opens to
break the by-pass circuit to the next above
AX-5 auxiliary box. Thus, when a release box is
installed, it is automatically inserted in the
bomb release circuit.
When both arms are cocked after installation
on the rack, place the bombardier's bomb
release lever in the LOCK position. When the
bombs, with shackles attached, are hoisted into
position and the shackles attached to the sup-
porting hooks on the racks, the shackle levers
will fit into the ends of the release box arms.
ARMAMENT 35

RESTRICTED
TYPE No.
AX-5
MALLORY
---ELECTRICAL
RECEPTACLE
-----BY-PASS
SWITCH
B-29 FAMILIARIZATION
AND MAINTENANCE
AX-5 AUXILIARY BOX
PURPOSE: To provide an electrical connection
for the A-2 release box. It also contains a short-
ing switch which automatically by-passes the
release circuit for its station if the A-2 release
box is not installed.
LOCATION: One AX-5 auxiliary release box is
permanently installed at each bomb station
on the bomb racks.
OPERATION: Each box has an electrical recep-
tacle into which fit the three pins of the A-2
release box plug. Only two pins are wired in
the B-29 airplane since no bomb position signal
lights (third pin) have been provided. When
the A-2 release box is not installed, the release
circuit 'is continuous through the shorting
switch in a given AX-5 box to the succeeding
AX-5 boxes above.
Each AX-5 box has a small bakelite button
which is depressed by the A-2 box when in-
stalled. When depressed, this button opens
the shorting switch to .the circuit through the
AX-5 auxiliary box to succeeding stations.
When plugged in, the A-2 release box con-
tinues the circuit to the succeeding stations as
long as its arms are not cocked. When the
arms are cocked, the circuit is established by
the transfer switch through the solenoid coil
to ground.
36 ARMAMENT

RESTRICTED
INTERVAL ADJUSTMENT-----------=.;
B-29 FAMILIARIZATI □ N
AND MAINTENANCE
,._----DIAPHRAGM CHAMBER
-----SOLENOID ACTUATING SHAFT
Tl'M E DELAY RELAY
TIME DELAY RELAY (AGASTAT)
PURPOSE: To close the circuit to the solenoid
which thrusts a red filter over the bomb release
formation white light when a bomb is released:
and, to delay the opening of this circuit until
five seconds· after bomb release.
LOCATION: In the bombardier's instrument panel.
OPERATION: The time delay relay is connected
in parallel with the RS-2 rack selector relays.
Thus, when the bomb interval control unit origi-
nates a release impulse, the solenoid coil of
the time relay is energized. This causes a mov-
able core to compress a spring, closing the
switch contacts to the formation light solenoid,
and pulling a diaphragm down to draw air
through a quick-release valve into the lower
chamber of the timing head of the unit. After
the release impulse ceases, the solenoid coil
in the time-delay relay is de-energized. The
spring forces back the core and the diaphragm,
forcing the air in the lower chamber through
an orifice to the upper chamber. At a prede-
termined point in its upward stroke, the dia-
phragm strikes the quick-release valve, remov-
ing the restriction to the air flow. The resultant
accelerated movement of the diaphragm dur-
ing the rest of the stroke opens the switch con-
tacts with a snap action which minimizes arcing
across the contact points. When the circuit is
broken, the formation light solenoid is de-ener-
gized, removing the red filter from the white
lamp.
The time-delay period is controlled by the rate
of air flow through the orifice and is adjusted
by a thumb screw on the face of the unit. The
delay period is preset for approximately five
seconds.
ARMAMENT 37

RESTRICTED 8-29 FAMILIARIZATION
AND MAINTENANCE
BOMB RELEASE FORMATION LIGHT
PURPOSE: In mass or pattern bombing. to signal
airplanes following in the formation when
bombs are being dropped.
LOCATION: The light is mounted on the fairing
above the tail gunner's rear window.
OPERATION: The light consists of a white lamp
mounted in a reflector and a solenoid-oper-
ated transparent red filter. The lens is painted
black except for a clear, narrow vertical strip
at the center, and is mounted flush with the tail
gunner's enclosure fairing.
When the bomb doors are open. the light
shines white to the rear. As each bomb is
released, the red filter is thrust over the light
by a solenoid energized through the time
delay relay. The red light shows for approx-
imately five seconds after the bomb is
released. If the release interval in a train
release is less.than five seconds, the light shows
red continuously until about five seconds after
the last bomb in the train has been released.
The lamp is connected to the bomb safety
relay so that it will light when the bomb door
safety switches close, energizing the bomb
safety relay. The bombardier's bomb door light
will glow amber at the same time, as it is also
connected to the bomb safety relay.
A toggle switch on the bombardier's control
panel controls the brightness of the bomb
release formation light. The switch has three
positions: OFF-BRIGHT-DIM. In the dim
position, a resistor is inserted in series with the
lamp.
BOMB SHACKLES •
PURPOSE: To carry the bomb on the bomb rack
and to release the bomb and release or retain
the loop of the fuse arming wire when the
shackle levers are operated.
LOCATION: The shackle is hung on two self-lock-
ing bomb hooks on the sides of the bomb rack.
The two lugs of the bombs fit into the ends of
the shackle.
DESCRIPTION: Three types of bomb shackles are
used for various bomb loadings: Type B-7
shackle for I00-pound to I000-pound bombs,
D-6 shackle for 1600 and 2000-pound bombs,
and D-7 shackle for 4000-pound bombs.
The three types of shackle are identical in func-
tion and general arrangement, differing only
in detail. The type B-7 is described below.
The frame is made from two steel stampings.
At the upper ends are the pins by which the
shackle is hooked to the bomb rack. At the
lower ends, two hinged release hooks hold the
bomb lugs. The forward end of the frame is
stamped FRONT. The shackles can be used on
either the left or right hand racks. There are
two levers at the upper side of the shackles.
The release lever is to the front and the arm-
ing leveris to the rear. When the release lever,
which is hinged at the bottom, is slanted for-
ward, it is engaged by a hinged pawl. A trigger,
attached to the interconnecting link between
the two hinged release hooks, extends through
the top of the shackle, forward of the release
lever.To lock the release hooks closed, a lug on
the bottom of the connecting link engages a
notch in the pawl.
To install the shackle on the bomb lugs, slant
the release lever back, releasing the pawl at its
aft end. A screw driver inserted in the forward
inspection hole forces the pawl down against
its spring. The release hooks are then opened
by pushing the trigger aft. The release lever is
then slanted forward so that after pushing the
trigger forward, the pawl engages both latch
surfaces. When the trigger is released, the
release hooks will close on the bomb lugs.
The bomb drops free when the release lever
is forced aft by the arm on the A-2 release box.
(See A-2 RELEASE BOX.)
The small propeller on the nose of the bomb is
spun off th~ fuse shaft by the air stream during
fall, arming the bomb to explode on impact.
To prevent the arming propeller from being
spun off by the air stream when the bomb doors
are opened, and to make the bomb safe to
handle on the ground, a safetying pin is in-
serted through holes in the propeller and the
threaded shaft of the fuse. A length of arming
wire is secured to this pin and is led up through
the front bomb lug to the shackle. The end of
the wire is formed into a loop which is inserted
in the slot in the shackle. A spring-loaded hook
must be pushed back so the loop will enter the
38 ARMAMENT

RESTRICTED
TO RACK
TO BOMB---
COCKING TRIGGER
TYPE D6
BOMB SHACKLE
1600 AND 2000 POUND BOMBS
TYPE 87
BOMB SHACKLE
100, 300, 500 AND 1,000 POUND BOMBS
-----ARMING ARM
TYPE 07
BOMB SHACKLE
4,000 POUND BOMB
BOMB SHACKLES
B-29 FAMILIARIZATION
AND MAINTENANCE
slot and be held. The hook is wedge-shaped so
that a force not greater than four pounds is
required to pull the loop out of the slot when
the arming lever is sl~nted aft.
pin from the hole in the arming propeller and
shaft so that the propeller may turn free on
the threaded shaft.
When the bombs are dropped electrically, the
arming lever is pushed forward and the lock on
the bottom of the arming lever is forced under
the hook. When the bomb falls, the wire loop
will be retained in the slot, pulling the safetying
When the bombs are salvoed mechanically,
only the release lever is moved and the arming
lever remains in its initial position, the wire loop
is pulled out of the notch free of the spring-
loaded hook. The wire falls with the bomb and
the bomb is not armed to explode on impact.
ARMAMENT 39

RESTRICTED B-29 FAMILIARIZATI □ N
AND MAINTENANCE
40
==== -= - =----c I
BOMB RELEASE SEQUENCES
With the aid of the diagram shown on the
opposite page, the sequence of release can
be determined for any bomb loading. A check
should be made to insure that the following
conditions are met:
I. No center racks must be installed if side
racks are installed at positions Front Left-2,
Front Right-2, Rear Left-2 or Rear Right-2.
2. With a partial bomb load, each rack must
be loaded so that unloaded stations always
occur at the top of the rack.
3. 4000-pound bombs must not be loaded at
any stations other than those shown on the
4000-pound rack diagram.
4. Bombs larger than those indicated at each
station must not be loaded at that station.
5. When auxiliary bomb bay fuel tanks are
installed, the corresponding bomb bay tank
safety switch should be turned to the OFF
position. This will eliminate bomb groups I and
Ill from a release sequence if the tanks are in
the front bomb bay: groups II and IV will be
eliminated if the tanks are installed in the aft
bomb bay.
The release sequence will always start with I
and proceed through 11, Ill and IV in that order,
if:
a. All four bomb group selector switches are
flipped to OFF, then ON before releasing
bombs: or,
b. the power to the buses is completely shut
off: or,
c. the bomb doors are closed between bomb
releases.
As shown on the diagram, there are three
receptacles on each side of each bomb bay
and two receptacles for the center racks in
each bomb bay. When a rack plug is inserted
in the receptacle, the jumper switch connec-
tions between terminals A and 81 and between
terminals C and D are opened so that the two
rack circuits are inserted in the release cir-
cuits.
On the I000-pound racks, stations I, 2, 3, 4, and
5 are in series from terminal A through to ter-
minal B. From here, the circuit continues to the
next receptacle in that bomb group. Rack sta-
tions 6, 7, 8, 9, I0, and 11 are in series from ter-
minal C through to terminal D and, from this
terminal, the release circuit continues to the
next receptacle in the circuit.
On the center racks, station I is served by ter-
minals A and B, and station 2 is served by
receptacle terminals C and D. On the left hand
4000-pound racks, terminals A and Bserve only
station I: terminals C and D serve the other
three stations. The wiring for the right hand
4000-pound racks is similar except that ter-
minals A and Bserve the two lower stations of
the five provided, and terminals C and D serve
the upper three.
Note that on receptacles Front Left-2 and
Rear Left-2, terminals Band Care permanently
interconnected so that the release sequence
is from the bottom to the top of the rack,
releasing a bomb each time the bomb group
circuit for the rack receives a release impulse.
When rack plugs are inserted in receptacles
at Front Left-2, Front Right-2, Rear Left-2, and
Rear Right-2, no other receptacles will have
rack plugs installed. Therefore, the impulse
connections from Front Right-2 and Rear
Right-2 are tapped off the interconnecting
wires to the other right hand receptacles.
The bomb group circuits are identified as I, 11,
111, and IV to correspond with the identification
of their respective rack selector relays as
shown on the BOMB CONTROL CIRCUIT
DIAGRAM and on the RS-2 RACK SELEC-
TOR RELAY OPERATION. This designation
also corresponds to their sequence of release
when all bomb group selector switches are in
the ON position.
ARMAMENT
- 1

RESTRICTED
NOTES

RESTRICTED
...--+--''---.----<' A
---..rB
,--.+----.---<'C
,....:---<D
FRONT RIGHT
No. 1 RECEPTACLE
'-f--....---< A
...........-~-B
--..;...._--c
D
FRONT BOMB BAY
FRONT RIGHT
No. 2 RECEPTACLE
._____-<A
------B
r-+------<C
---<D
FRONT RIGHT
No. 3 RECEPTACLE
----..rA
---..........-B
-----<C
--4---<D
REAR RIGHT
No. 1 RECEPTACLE
r - - A
......+----<B
-1------<C
L-_-_--<D
REAR BOMB BAY
REAR RIGHT
No. 2 RECEPTACLE
'-------<A
,____ _ _ _ _ _ _........__...,.---< B FRONT CENTER
C No. 1 RECEPTACLE
---------+--.......,-<D
---.--<A
.....____ B FRONT CENTER
----<C No. 2 RECEPTACLE
-----<D
FORWARD~
L---------+----.--<A
-------<B
-----------11-----.--<c
D
REAR CENTER
No. 1 RECEPTACLE
...____<A
-----s
----c
.....,._..,_<D
FRONT
BOMB BAY
SAFETY
SWITCH
t
o-........i1-----......-<A
B
---------c FRONT LEFT
No. 1 RECEPTACLE
~--<A
__._____._-<B
------<C
FRONT LEFT
No. 2 RECEPTACLE
i...+--.---<A
--+----<B
............---<C
----<o
FRONT LEFT
No. 3 RECEPTACLE
D -------D
FROM TERMINAL E ON FIRST RS-2 RACK SELECTOR RELAY, BOMB GROUP CIRCUIT I } SEE RS-2 RACK SELECTOR RELAY
FROM TERMINAL EON SECOND RS-2 RACK SELECTOR RELAY, BOMB GROUP CIRCUIT Ill CIRCUIT AND OPERATION DIAGRAM
____ + RA,.....C_K_S_T_A_T1_o_N_s_____________.__ __,
liooLB.~~ ®7
I300LB.~~ '1o
I 500 LB. - - .J ~ I
lOOOLB.[~ ® I
100 LB.,-:---, © I
300LB.L~ I
500LB.[~ 01
r---, IL' I
100 LB.L _ J .V I
300LB.rr~ © 1
1000 LB.L - .J ___,;:=--+------'
lOOLB.r~ 14' I
SOOLB.L - J '-:v
100 LB.r- - :, (j I
300LB.L~ .VI
1
,gggt~:r~ 0 I
, ,oo LB.r,--~ 0 1
300 LB.L - J
L ____ _
LEFT AND RIGHT 1000 POUND
BOMB RACKS
ABCD
CONNECTOR PLUG TERMINAL
FOR
LEFT 100, 300, AND
500 LB. BOMBS
FRONT LEFT No. 1
FRONT LEFT No. 3
AND
REAR LEFT No. 1
REAR LEFT No. 3
LEFT 1000 LB.
BOMBS
FRONT LEFT No. 2
REAR LEFT No. 2
RIGHT 1000 LB.
BOMBS
FRONT RIGHT No. 2
REAR RIGHT No. 2
RIGHT 100, 300 AND
500 H. BOMBS
FRONT RIGHT No. 1
FRONT RIGHT No. 3
AND
REAR RIGHT No. 1
REAR RIGHT No. 3
r __ -- _ 4~c_K_S_T_AT_IO_Ns
______
lsoo LB.,--, 12" 1
I L - J ~ I
I r - - - 7
I500 LB. L I 0 I
L _____ .J
CENTER 500 POUND
BOMB RACKS
(FOUR IDENTICAL RACKS)
ABCD
CONNECTOR PLUG TERMINAL
FRONT CENTER No. 1
FRONT CENTER No. 2
REAR CENTER No. 1
REAR CENTER No. 2
I2000 LB.r - - - i
I L - J
I
I r---,
I1600 LB.L _ J
I
I
I
01
I
I
0'I
l2000LB.r - - -1 I
11600 LB.L - J 0 I
L_____ __j
LEFT 4000 POUND BOMB RACK
(TWO IDENTICAL RACKS)
r---,
I
I
I
A BCD
CONNECTOR PLUG
TERMINAL
FRONT LEFT No. 2
OR
REAR LEFT No. 2
NOTE
DC BA
CONNECTOR PLUG
TERMINAL
FRONT RIGHT No. 2
OR
REAR RIGHT No. 2
1000 POUND BOMB RACKS ALSO
ACCOMMODATE 100, 300
AND -500 POUND BOMBS.
4000 POUND BOMB RACKS ALSO
ACCOMMODATE 1600 AND
2000 POUND BOMBS.
B-29 FAMILIARIZATION
ANO MAINTENANCE
......,__.,_<: REAR RIGHT
-..;...._----rc No. 3 RECEPTACLE
D
REAR CENTER
No. 2 RECEPTACLE
1
~RA~TATION~
I©I~i]1600LB.1
I14'
1
r~~f2000LB_I
I:) - J I
Ir,; r---, I
I0 L - J 1600 LB.
I
I01 [~3J4000LB.I
I(j'I r - - - 12000LB.I
I.V L _ J1600LB.I
L _____ _j
RIGHT 4000 POUND BOMB RACK
(TWO IDENTICAL RACKS)
- - - - - - -~-~~.
~-~~--~~~~-~~~~~~~~~~~~~~~~~~~~~~~-~--~~~-~~~~~
BOMB RELEASE SEQUENCE CIRCUIT
- - - - - - - - -
- - - -
- - - -
- - - -
- - - - -
- ====== -========== - - ~~~~====-
ARMAMENT 41

B- 29 ,-AMI LIARIZATION
ANO MAINTENANCE

RESTRICTED 8-29 FAMILIARIZATION
AND MAINTENANCE
BOMB RACKS
PURPOSE: To support the bombs and bomb
release mechanisms.
GENERAL DESCRIPTION: Three sizes of bomb
racks are provided for the forward and aft
bomb bays. These are: the center racks for
500-pound bombs, the left and right hand
racks for I000-pound bombs and the left and
right hand racks for 4000-pound bombs. Each
rack is interchangeable with others of its own
· size on the same side of the airplane. All the
center racks are interchangeable.
A I000-pound bomb rack has eleven stations to
hold bombs weighing I00, 300, 500, or I000
pounds. On later airplanes, all stations for I00
or 300 pound bombs will be eliminated.
Bombs may be loaded in the racks in the follow-
ing groupings:
IO00-pound side racks-500-pound center racks
Number of racks Bomb Number of bombs Total number
(both bomb bays) on each rack of bombs in
(left} {center) (right) {pounds) (left) (center) (right) both bomb bays
4 4 4 100 6 2 6 56
4 4 4 300 5 2 5 48
4 4 4 500 4 2 4 40
2 none 2 1000 3 none 3 12
4000-pound side racks - no center racks
Number of racks Bomb Total number
(both bomb bays) Number of bombs of bombs in
(left) (right) (pounds) on each rack both bomb bays
2 2 1600 3 12
2 2 2000 2 8
2 2 4000 I 4
ARMAMENT 43

r----~--~~- ----~- - .-- -
RESTRICTED
The rails of the side racks mate with fittings on
the catwalks and the bomb rack support beams
above the catwalks. The entire weight of the
rack and its bomb load is carried by the lower
fittings on the catwalk.To insure this, the holes
in the upper rail fittings are slotted vertically
and as a consequence the support beam only
stabilizes the bomb rack. Since bomb racks do
not contribute to the strength of the airplane
structure, the airplane may be flown without
racks installed.
Bomb SURport hooks are bolted to the sides of
the rails. They have a spring-loaded catch or
guard which prevents the bomb shackles from
becoming unhooked accidentally. Gusseted
cross members space the two rails the proper
distance to accommodate the bomb she1'.;kles.
To a vertical panel secured to these cross
members are attached the AX-5 auxiliary
boxes, the permanent wiring of the racks, the
A-2 release boxes, and the selector bar with
its associated linkages.
The center racks have two semi-circular yokes
to which the rails attach. The yokes attach to
B-29 FAMILIARIZATION
AND MAINTENANCE
support beams on either side of the tunnel. A
brace is rigged between the two center racks
in the forward and aft bomb bays. The aft cen-
ter rack in the forward bomb bay is braced
against fore and aft loads by a tripod structure
attached to t~e wing front spar. Bracin
1
g for
the forward center rack in the aft bomb bay is
attached to the rear spar.
Decals on the catwalk and on the bomb rack
support beams indicate fittings in which each
rack may be installed. Ei.ght receptacles for
the rack electrical plugs are provided in both
forward and aft bomb bays. Three are located
on each side and two in the center in each
bomb bay.
Self-locking pins att.ach the racks to the body
fittings. To insert the pin, its plunger is
depressed. When the plunger is released, the
compression spring pushes the plunger back
out, forcing a ball, held in the side of the
inserted end of the pin, out above the pin sur-
face, safetying the pin.
44 ARMAMENT

RESTRI CTED
NOTES
- ~ - --- - - -
- -

(
RESTRICTED
BELL CRANK----
SELECTOR BAR-------::;::
CENTER RACKS FOR
100, 300 AND
500 POUND BOMBS
RACK PLUG CABLE
ELECTRICAL CONNECTION
= - ~ - -
,....-:-----CABLE
ELECTRICAL CONNECTION ---e~~i:::::=;;;;::=;::===~
BELL CRANK
MECHANISM,---.=-~
BOMB RACK
FRAMES--------~
LOWER
ATTACHMENT
SIDE RACKS FOR 100, 3001 500
AND 1000 POUND BOMBS
BOMB RACKS
ARMAMENT
..,,.____ RACK PLUG
~-~~-=b.~JiJ--ELECTRICAL
CABLE
UPPER
ATTACHMENT--..::.:
AX-5 AUXILIARY
RELEASE BOX--.;...._.=:.____
CAM SLOT
RACKS FOR 1600
2000 AND
4000 POUND BOMBS
- -- - -~-§-~-~-~-~ - - -
- - -
CONNECTION
......--- SELECTOR BAR
ACTUATING
ROD
45

B- 29 P'AMILIARIZATIDN
AND MAINTENANCE

RESTRICTED 8-29
FAMILIARIZATION
AND MAINTENANCE
BOMB HOISTING
DESCRIPTION: Components of the C-3 bomb
hoist consist of two opposite-hand support
brackets, a windlass assembly to fit on each
support bracket, and hand cranks to drive the
windlasses. Electric motor drives, instead of
the c11anks, may be used to operate the wind-
lasses.
Two hoists, one on each side of the bay, are
used for all weights of bombs up to and includ-
ing 2000 pounds. In this way, both ends of the
bomb sling are raised and the bomb is pre-
vented from rolling. Four hoists and two slings
are used for 4000-pound bombs.
Bomb hoist brackets are aluminum alloy cast-
ings. Two brackets, on opposite sides of the
bomb bay, are mounted on four steel bolts on
the outboard side of opposite bomb racks. The
primary purposes of the brackets are to hold
the windlass assemblies, to secure the motor
drives when installed, and to support the pulleys
at their upper ends over which the windlass
cables lead. The windlass bearings on the
bracket have hinged bearing caps to facilitate
installation of the windlass. The caps are held
in place by wing nuts.
A spur gear on the shaft of the windlass cable
drum is turned by a worm gear. Since the same
windlass unit can be used on either the left or
the right hand brackets, the worm gear shaft
is designed to be driven from either end by the
hand crank or the electric motor unit. The
motor drive units must rotate in the same direc-
tion, not left hand and right hand, as normally
supplied with the C-3 bomb hoist.
Crank handles have three box type sockets,
providing different crank lengths for hoisting
various sized bombs and are stowed on the
support brackets.
Bomb hoist slings consist of two webbing straps
parallel to each other, their ends joined and
bolted to metal yokes to which the hoisting
cables are attached. When hoisting, the weight
of the bomb must be evenly distributed
between the straps of the sling. The straps
must be straight and lie flat on the surface of
the bomb. Chain type slings are used for some
bomb types.
HOIST MOTOR DRIVE: The bomb hoist motors
are energized through a control box from a
24-volt D.C. or from a 110-volt A.C. external
power supply. A control box at the end of a
flexible cable is held by the hoist operator. The
main hoist control box is on the ground. The two
hoist motors are operated together to turn
the two windlasses on opposite bomb racks at
the same rate of speed and in this way pre-
vent the bomb from rolling.
PULLEY YOKE: A removable sheet metal pulley
yoke is pinned to fittings on the center rack
support beams at either side of the tunnel, to
hold pulleys for the windlass cables before
hoisting bombs of less than 4000-pound weight.
The yoke has 12 holes for various pulley combi-
na.tions which are used so the cables can lift
vertically from the bomb sling. This avoids the
placing of greater load than necessary on the
hoisting cable. The fittings on which the yoke is
hung allow the yoke to swing fore and aft, to
align with the hoist cable.
ARMAMENT 47

CENTER BOMB RACK YOKE
::z:
C,
CENTER BOMB RACK
- B-7 BOMB SHACKLE
en FUSE
-I
-
:z
m
C,
~
::s-,
:a
Cl'I
:I:
::s-, 0
:I: C,
l"'l"I
::z:
..... -a
c:,
=
:z
C,
m
C,
==
m
en
PULLEYS LOCATED AT---------
YOKE HOLES 4-5-9
FOR CENTER RACKS
~>-:----- SELECTOR BAR
ACTUATING ROD
BOMB HOIST
BRACKET
SUPPORT
WING FRONT
SPAR
__.;;,__ BOMB HOIST
WINDLASS
SELECTOR
BAR
:.,._.;=.-BOMB DOOR
::-=---------BOMB BAY DOOR~(OPEN)
--;--~.........-----------STATION 218
ACTUATOR
► "'1
z ►
0 ~
~r
►-
-►
z;1:1
-i -
l'l N
z ►
► -i
z-
nD
(Tl z

RESTRICTED
Self-locking pins are used for pulley axles and
to secure the yoke to the beam fittings.
HOISTING: Bombs arrive under the racks on a
bomb cart. The bomb shackles are snapped on
the bomb lugs and the arming wire is rigged.
The sling is then placed under the bomb in the
proper position for balance. The hoist cables
are routed over the pulleys properly located
for vertical hoisting, and then hooked to the
slings.
If the motor drives are used, the operator
pushes the lift control button. Both hoist
motors are energized simultaneously. When
the bomb is in position to be rolled, the opera-
tor pushes the "roll" button. One motor slacks
off and the other takes up cable, rolling the
bomb into position so that the shackle can be
hooked on the rack. The arming and release
levers fall into place in the arms on the A-2
release box, which has been cocked and
locked against mechanical or electrical release
by placing the bombardier's bomb control
lever in the LOCK position.
After the bomb shackle is hooked, slack off the
hoist cables and unlock the sling.To unwind the
cables, push the "down" button.
Bombing-up time can be reduced considerably
with a well-coordinated team. Because of its
8-29 FAMILIARIZATION
AND MAINTENANCE
large bomb capacity, this factor is particularly
important when loading bombs in the B-29 air-
plane.
If the motor drives are not available, the wind-
lasses are operated with the hand cranks. Care-
ful coordination of cranking rate is required to
avoid rolling the bomb in the sling until it is in
the proper position.
Bomb hoisting ·procedure is essentially the
same for all bomb sizes except for 4000-pound
bombs.
The pulley yoke will not handle 4000-pound
bombs,which require four hoists. A derrick-like
structure is mounted on the fore and aft mem-
ber of the right hand rack to support the pul-
leys over which the hoist cables run to hoist
the left hand bomb.
To provide a vertical hoist for the left hand
cables for hoisting the right hand bomb, a rod
is attached to each of the right hand bomb rack
rails. Pulleys at the lower ends of the rods carry
the cables from the left hand hoists so that
these cables lift vertically from the slings.
Two slings are employed for hoisting 4000-
pound bombs. Extremely careful coordination
of the four hoists is required to prevent tipping
or rolling the bomb.
ARMAMENT 49

:z:
c::»
- ARMING WIRE
en
....
-
z
a,
c:::,
-n
-
:a ...
:!ii: Q
- m
:!ii:
,., Q
::z:
.....
-a
c:::,
C:
:z
Cl
m
c:::,
~
m
en
TUNNELSUPPORT------------
PULLEY YOKE-------
B-7 BOMB SHACKLE---------
FUSE------
;:::::;;;:;,,---
· PULLEYS LOCATED AT YOKE HOLES 5-8-12
~ ,~R,. BOMB RACK SUPPORT BEAM
,~~-'------SELECTOR BAR
ACTUATING ROD
BOMB HOIST
BRACKET
SUPPORT
:....--..,:;:.,..---WING FRONT
SPAR
~'"---BOMB HOIST
MOTOR DRIVE
BOMB DOOR
ACTUATOR
~;;;;,.-- AX-5
~ AUXILIARY
BOX
BOMB SLING
--------CATWALK
-------
✓
~Y
:.....·-~TA110-N_2_1__
8______BOMB BAY DOORS (OPEN)
)>,i
z )>
cI
-
Ir
)> -
- )>
z ;u
-1-
1'1 N
z>
)>-t
z-
nO
11'1 z

c.n
-
-
-
z
a,
....
en
C,
C,
(
TUNNEL SUPPORT
PULLEY YOKE------------.....
A-2 RELEASE BOX---------.
D-6 BOMB SHACKLE-------
(
--,.--~-,------PULLEYS LOCATED AT
YOKE HOLES 4-5-8-9
~ ~--------BOMB RACK
SUPPORT BEAM
,~-------SELECTOR BAR
ACTUATING ROD
:;.,----FORWARD BOMB DOOR
DRIVE MOTOR
BOMB DOOR
LIMIT SWITCH
----BOMB DOOR
ACTUATOR
BOMB DOOR
DRIVE GEAR BOX
.a.......--BOMB HOIST
WINDLASS
SELECTOR BAR
CAM SLOT
AX-5 CONNECTOR BOX
'---------------STATION 218
)>"'1
z ►
al'.
-
l'. r
►-
- )>
z ;o
-i -
Ill N
z )>
)>-i
z-
Cl □
Ill Z

c.n
TUNNEL SUPPORT
....,
PULLEY YOKE
D-6 BOMB SHACKLE
=
= FUSE
-
en ARMING WIRE
-I
-
:z
en
=
..,,
=--
::a N
:I: c::»
=-- c::»
:I:
,.., C,
::z
......
-a
=
C:
:z
~
a,
=
a:
a,
fA
.----~~;,;,,,,---PULLEYS LOCATED AT YOKE HOLES 6 AND 8
~-----------BOMB RACK
SUPPORT BEAM
~
~:~,,...-.,----SELECTOR BAR
ACTUATING ROD
FORWARD BOMB DOOR
DRIVE MOTOR
BOMB DOOR
LIM IT SWITCH
---BOMRDOOR
ACTUATOR
"'- BOMB DOOR
DRIVE GEAR BOX
.......---'--BOMB HOIST
BRACKET SUPPORT
-----MOTOR DRIVE
=---...;.._ BOMB RACK RAIL
~ - - CAM SLOT
~--SELECTOR BAR
~~:;'-~.;-,..;-..:..;.../
_
. -~......
,~,...;:;...-------STATION 284.29
...,__;;;~-
/:-----~------BOMB SLING
- -
/ -~;;..._---------CATWALK
~ / - - - - B O M B BAY DOORS OPEN
-----------STATION 218
)>-ri
z ►
oI
Ir
►-
- )>
z ;o
-1-
"' N
z ►
)>-I
z-
nO
"'z

( (
TUNNEL SUPPORT COMMUNICATION ::a
TUNNEL ....,
~
BOMB HOIST BRACKET SUPPORT BOMB RACK .....
(FOR UPPER 4000 POUND BOMBS ONLY) SUPPORT BEAM
::a
c-,
.....
A-2 RELEASE BOX SELECTOR BAR
....,
C,
ACTUATING ROD
=
C) D-7 BOMB SHACKLE
-WING FRONT SPAR
-
en
....
-
z FUSE
C,
C)
-n
:a::-, BOMB HOIST
::a .. BRACKET SUPPORT
:I:
= CAM SLOTS
:a::-,
C,
:I:
....,
=
::z:
_,.
-a
C,
C:
z
c:,
m AX-5
C) AUXILIARY BOX cc,
== STATION 284.29 ~
CJ:)
m BOMB SLINGS )>"TJ
en z ►
cI
CATWALK Ir
)> -
- )>
z ;o
-i -
BOMB BAY DOORS (OPEN)
111 N
z )>
)>-i
z-
n □
c.n
STATION 218 111 Z
~

RESTRICTED B-29 FAMILIARIZATION
AND MAINTENANCE
DEFENSIVE ARMAMENT
GENERAL DESCRIPTION: Guns in the turrets of
the B-29 airplane are sighted and fired from
sighting stations remote from the turrets. The
electrically-powered and controlled turrets
are located in the most advantageous positions
relative to their fields of fire. Sighting stations
are located to obtain the best visibility and for
operation within the pressurized compart-
ments.
Both upper turrets and the lower front turret
extend into the pressurized compartments, but
are sealed from the cabin so that the air pres-
sure within these turrets is atmospheric. The
tail turret is sealed by the armor plate bulk-
head from the tail gunner's (pressuri~ed) com-
partment.
Each upper and lower turret mounts two .50
caliber Browning machine guns, with 500 rounds
of ammunition per gun, carried in removable
magazine cans. The interior and exterior tur-
•et domes must be removed to load the ammu-
nition cans in the turrets. On later airplanes,
the ammunition carried will be increased to
1000 rounds per gun.
Two .50 caliber machine guns and a 20 milli-
meter cannon are emplaced in the tail turret.
110 rounds of 20 mm. ammunition is carried
in a removable magazine in the tail turret.
Machine gun ammunition is carried in two
boxes forward of the tail gunner's compart-
ment on either side of the walkway. Ammuni-
tion belts pass through sealed tubes in the tail
gunner's pressurized section to the unpressur-
ized tail turret. The belts are pulled from the
boxes by an automatic electrical feed system
relieving the gun of this load. Whenever there
is any tension on the ammunition belt, a switch
is closed to start a motor-driven sprocket
which pulls the belt.
There a re five sighting stations: one upper
station employing a ring sight with which the
operator has primary control of the aft upper
turret, and secondary control of the forward
upper turret; the tail sight section, employing
a pedestal sight with which the tail gunner
has primary control of the tail turret; the two
sideblister stations employing pedestal sights,
which share primary control of the lower rear
turret and, in addition, have secondary control
of the lower front turret and the tail turret.
The sight at the bombardier's sighting station
is mounted on a pantograph bracket so that
the sight can be swung out of the way when not
in use. With this sight, the bombardier has pri-
mary control of the upper and lower front tur-
rets. Secondary control is available to the aft
compartment stations when the operator at
the bombardiers station (who normally has pri-
mary control) releases his action switch on the
sight.
The fire of the forward turrets converges
ahead so that the fire of both turrets can be
concentrated to combat head-on attacks. As
the front sight moves in elevation, control will
pass from one forward turret to the other, so
that at least one turret will bear on a forward
target.
The upper forward turret of early B-29 air-
planes was under primary control of only the
top gunner with no provisions for secondary
control. This system, however, will have been
modified to the present system as described
above.
54 ARMAMENT

RESTRI CTE0
NOTES

RESTRICTED
BOMBARDIER'S
TABLE
STATION
23.5
GUN SIGHT AIMING POINT CAMERA
.50 CALIBER GUNS
SERVO AMPLIFIER
LOWER FORW ·' CAME I
ARD TURRET CONTROL BOX RA INTERVALOMETER
AMPLIDYNE
FORWARD GUN AND CAMERA LOCATIONS
ARMAMENT
PRESSURE
BULKHEAD
STATION
218
TURRET SAFETY SWI /". ..i.·.•.
TCHES , , .•.~
ALTITUDE T
AND EMPERATURE
AIRSPEED UNIT
STATION 185
.50 CALIBER GUNS
~·
~ J,
· . ~
SINGLE PARALLAX
COMPUTER
LOWER FORWARD TURRET
STATION 135
55

8 - 29
NOTES
FAMI LIAAIZATION
AND MAINTENANCE

RESTRICTED
NOTES

CONTROL BOX
.50 CALIBER AMMUNITION TRACK
TURRET SAFETY SWITCH
.50 CALIBER AMMUNITION BOX
.SO CALIBER GUNS
UPPER REAR TURRET
SERVO AMPLIFIERS
AMPLIDYNE
BLISTER CONTROL BOX
AMf'LIDYNES
UPPER SIGHTING
BLISTER-
UPPER GUNNER'S
SIGHT-
AUXILiARY CONTROL
SWITCH BOX-
RIGHT ,HAND
UPPER CONTROL
BOX
.
VERTICAL CAMERA
RIGHT HA
OBLIQUE CA~~RA
TYPE K-20 CAMERA
PRESSURE
BULKHEAD
STATION
834
I
-DYNAMOTOR
STATION 696
COMPUTER VOLTA,..
BLISTER SWITC JE REGULATOR
H BOX
,------l
STATION 1039.9
DYNAMOTOR
I lJ,,___ AMMUNITION BOX
L__ .50 CALIBER GUNS
LOWER REAR TURRET
CAMERA JUNCTION BOX
LEFT HAND OBLIQUE CAMERA
TURRET SAFETY SWITCH
STATION,706
COMPUTER .ARMOR PLATE
SINGLE PARALLAX COMPUTER
DOUBLE PARALLAX COMPUTER
AUXILIARY CONTRO
DOUBLE PARALLAX L SWITCH BOX
LEFT HANDCOMPUTER
GUNNER'S SIGHT
REAR GUN AND CAMERA LOCATIONS
ARMAMENT
- - - - - - - - - - PRESSURE BULKHEAD STATION 1144
------------TAIL GUNNER'S ARMOR
PRESSURE BULKHEAD STATION 1114
ill...-------- TAIL GUNNER'S SIGHT
--------20 MM CANNON M-2
:--,------.SO CALIBER GUNS
- - - - - - - - - - GUN CAMERA
TAIL TURRET
20 MM AMMUN
20 MM AMMUNITION BOX
·20 MM
GUN SWITCH
20 MM
FEED CHUTE
ASSEMBLY
SERVO
AMPLIFIER
AMPLIDYNES
ELEVATION DRIVE MOTOR
ELEVATION DR
VE MOTOR
AZIMUTH DRIVE MOTOR
57

B- 29
·NOTES
F'AMILIARIZATIDN
ANO MAINTENANCE