BOEING
B-29 SUPERFORTRESS
SOME FLYING INFORMATION
WARNING
This document contains information affecting the National Defense of the
United States within the meaning of the Espionage Act (U S.C. 50:31:32). The
transmission of this document or the revelation of its contents in any man-
ner to unauthorized persons is prohibited.
JF THIS DOCUMENT IS CARRIED IN THE AIRPLANE ON COMBAT MIS-
SIONS OVER ENEMY TERRITORY, SPECIAL CARE MUST BE TAKEN TO
SEE THAT IT IS DESTROYED BEFORE FALLING INTO THE HANDS OF
THE ENEMY.

Copyright, 1944
BOEING AIRCRAFT COMPANY
Seattle, U.S.A.
Document Number D-5655
Issue No. --------------------
Date ------------------ -------
Issued to --~~~-~.:-~~~,!!:,_!_
FIELD S!l!YJC! EHGINHII
■OEING AIRCRAFT COMPAN't
I AlTLI!:. WASIIINC.TON, U.S . -'•
Printed by
CRAFTSMAN PRESS
Seattle
TABLE OF CONTENTS
The B-29 Airplane
Page
Some of the Airplane's Background___ ____ 1
F1
ying Qualities ----------------------------------------------------------------__________ 4
Elevators __
_________________________
_____________----------------------------------___ 4
Ailerons ____ -------------------------------- ________________ 5
Rudder ---------------------------------------------------- ---------------------------· _ 5
Stability ____________
___
____________________________
______________
_
___________
___________ 6
More About Stalls _____ ____________________________ 6
Power Off Stalling Speeds__________________________________ _______ _____ 8
Performance -------------------------------------------
Dive Speeds _________
A Thing or Two
9
12
Taking Off .-------------------------------------------------------------- 13
Climbing ------------------------------------- ------------------------------------- 16
Leveling Off and Going Places___________________________________________ 17
Getting Maximum Endurance________________________________________ 27
Going a Long Way______________________ _
________________ 28
Flying in Formation ------------------------- __ 32
Emergencies in Flight_____________ 35
At Takeoff ________ ________________________ 35
Level Flight ---------------------·----- _________________ 36
Gliding ---------·- - - - - - _________________________ 39
Landing Approach ------------------------------------------------------------ 39
Landing _______.__________
_______________________________..________________________
_
______________ 40

Page
Emergencies in Landing ------------------------------------------------------------ 41
Refused Landing ----------------------------------------------------- 41
Short-Field Landing ________________
___ 41
Ditching or Water Landing ---------------------------------- 42
What to Do With the Power Plant________________________________ 46
Something About the Electrical System___________________
_______________ 50
Something About Cabin Pressure and Heat__________________________ 53
To Operate without Cabin Pressure________________________________ 55
To Operate with Cabin Pressure ------------------------ __________ 55
Testing Cabin for Leakage__________________________________________________ 56
Where to Get More Information________________________________________________ 57
LIST OF ILLUSTRATIONS
Page
Figure I-Comparison B-17, B-29, B-24___________________ 3
Figure 2-Center of Gravity Position Chart__________________________ 7
Figure 3-Ground Run vs. Airspeed Chart_____________ ___ 14
Figure 4- Engine Power Needed to Produce Lift_______________ 19
Figure 5-Engine Power Needed to Move____________________________ 20
Figure 6-Power Required Curve_______________ _ __ 21
Figure 7-Power vs. Speed Curve______________________ 22
Figure 8-Airspeed Conversion Chart __________________ 25
Figure 9-Airspeed Drag at 150 MPH and 220 MPH____________ 26
Figure IO-Airspeed vs. Miles per Gallon Chart_______________ 29
Figure 11-Long Range Cruising Chart_______________________ 30
Figure 12-Power vs. Speed Chart
(Comparative Conditions) ____ _ ___ 33
Figure 13-Propeller Windmilling Speed_______________ 38
Figure 14-Water Landing__________ _________________ 43
Figure 15-Engine Operating Limits___.__________ 47
Figure IS-Minimum Power Requirements Landing Gear
and Flaps --------------------------------------------------- 51
Figure 17- Cabin Supercharging___________________________________________ 54

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THE B-29 AIRPLANE
This book is written for those men who must know how
to use all they can get from the B-29. It will help explain
some of the things that must be understood. Here is what it
covers:
I. Some of the airplane's background
2. The flying qualities of the airplane
3. A thing or two about . ...
a. Taking off
b. Climbing
c. Leveling off and going places
d. Getting maximum endurance
e. Going a long way
f. Flying in formation
g. Emergencies in flight
h. Gliding
i. Landing approach
j. Landing
k. Emergencies in landing
4. What to do with the powerplant
5. Something about the . . .
a. Electrical systems
b. Cabin pressure and heat
6. Where to get more information
SOME, OF THE AIRPLANE'S BACKGROUND
The B-29 now goes under the name of "Superfortress."
It's up to the men who fly this airplane to show how "super"
it is. All of the men who have lived with it from away back in
1939 feel sure that it is "super". The story begins in the early
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part of 1939 when studies were started to find out how to
make a bigger and better airplane than the B-17. The XB-29
airplane design was determined in 1940 and three airplanes
were built as prototypes for the production of the B-29. The
first XB got into the air in the fall of 1942.
Even though the B-29 has gone beyond the abilities of
the B-17, it has a lot in common with the "Fortress". For
instance, the B-17 tail was one step in the development of the
tail now on the B-29. Many other qualities were copied
directly. A large amount of experimenting was done with a
B-17 to check the ideas that were thought of for the B-29. A
B-17 was flown with dual turbos, with the B-29 fin and rudder,·
with the B-29 stabilizer and elevator, and even with B-29
ailerons. The large props on the B-29 are the outgrowth of
experimental work on a B-17. All of the flight experience that
has made the B-17 what it is, was built into the B-29 in many
places.
However, every effort was made to design the B-29 so
that it was better than the B-17. It was made larger for one
thing. Aerodynamically it was made much cleaner so that it
would go farther and perform better. Although the B-17 was
continually improved as it grew older, gradually it was
realized that the only real way to beat the B-17 was to start
from "scratch" and build a new airplane. That airplane is the
"Superfortress".
Right now, the B-29 is the heaviest high speed American
airplane. The overall size is a little smaller than the Boeing
314 Clipper, but the weight, speed and power are much
greater. The diagram of the B-17 and B-24 compared with the
B-29 show why those two can be called medium heavies.
Their size isn't much different but the weight and power of
the B-29 is twice theirs and its speed is a good deal more.
When the airplane is loaded down with gas and oil for ferry-
ing, it holds almost as much fuel as a railroad tank car.
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824
BASIC WEIGHT
MAXIMUM GROSS WEIGHT
TAKE - OFF POWER
WING AREA
SPAN
LENGTH
37,400
60,000
4800 H. P.
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8I7 - G
BASIC WEIGHT 37,000
MAXIMUM GROSS WEIGHT 60,000
TAKE-OFF POWER 4800 H.P.
WING AREA 1,420 SQ. FT.
SPAN I 04 FT.
LENGTH 73 FT.
829
BASIC WEIGHT 72,000
MAXIMUM GROSS WEIGHT 120,000
TAKE-OFF POWER 8800 H. P.
WING AREA 1,738 SQ. FT.
SPAN 141 FT.
LENGTH 98 FT.
COMPARISON B-17, B-29 a B- 24
Figure 1 Page 3

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Here are some more interesting numbers:
Weight in Tons Horsepower
Superfortress ________________ 50
Ford V-8 ______ __________________ 1.5
Railroad locomotive ____ 350
Destroyer ______________________ 1,850
Queen Mary liner________ 81,000
FLYING QUALITIES OF THE AIRPLANE
8,000
85
2,000
52,000
200,000
Even with its large size and weight, the airplane has just
about the same flying qualities as smaller airplanes. Large
airplanes are usually slower in responding to the pilot's con-
trols because of their larger inertia. The control forces on the
B-29 are very light ,and even at low flying speeds, the combi-
nation of light forces with the high inertia of the airplane
seldom gives the pilot any impression of sluggishness and
not enough control. Just after taking_ off and then agai,!!_
durin the short interval of time while landing, the rudder
and the aileron control r;;-;;nse is slow but ver ositive.
~ontrols are as good and in many ways better than those
of many small airplanes. Once the pilot becomes familiar
with the controls, he will realize that the B-29 behaves like a
much smaller airplane.
Elevators
The elevator control is almost exactly like that on the
B-17. The size of the horizontal tail is exactly the same except
that the B-29 elevators have a little more balance and the nose
of the tail airfoil section is turned up so that the tail won't
stall when making a power-on approach to landing with the
flaps full down. It will be found that the elevator trim tab is
quite sensitive in high speed dives and care should be taken
not to overcontrol the airplane when flying with the trim tab.
Overloading the tail surfaces and other portions of the air-
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plane may occur due to such overcontrolling. Diving in
rough air should also be avoided.
Ailerons
The ailerons are quite large and can move the largest
possible amount (18 degrees up or down) so that the pilot
has as good control as could be built into the system. At very
high speed, the large ailerons have larger control forces than
other airplanes. That is the main reason for increasing the
control wheel travel over that now on the B-17. The extra
control comes in handy when an engine fails just after take-
off; or when, for some reason, fuel is used on one side of the
airplane and the other wing gets heavy. The effect of dif-
ferent amounts of fuel in the two sides will be noticed in the
aileron control whenffying straight and level. If the speed
is allowed to go down near the stall, the amount of aileron
needed to offset uneven wing weights will grow very rapidly.
Don't try any landing with this unevenness until the aileron
control is checked in flight at the landing speed.
The aileron trim tabs are geared to move when the
ailerons move. The shape of the wing airfoil contour is such
that the part covered by the ailerons has a hollow on top andI
is full on the bottom. If the control cables get cut during com-
bat, the ailerons would ordinarily trim down because of this
shape. To avoid this, the trim tabs are rigged down one inch
at the trailing edge and if the aileron cables are "shot-up",
the ailerons will then tend to trim more nearly neutral.
Rudder
The rudder will give the maximum possible control and
stability and yet the pilot can move it without the help of
power boosts. The diamond shape of the rudder is the result
of studies to find a rudder which will behave normally under
all flight conditions. Besides that, a good rudder is one that
can be moved with a small amount of effort when an engine
fails at any speed but does not become overbalanced or
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locked. The pilot should not be <:QD.fused by the vet~ .lighi
for5:.:;_s since they don't tell him what the rudde is doing to
the airplane-In landing approach conditions, it is possible
to get appreciable amounts of ~kid with very small effort.
Remember that it takes a certain amount of time to skid a
large airplane and also to stop the skid.
Stability
The longitudinal stability is normal and satisfactory for
all conditions which can be flown with the airplane. For good
flying characteristics, it is very desirable to keep the center
of gravity position within the allowable limits shown in Fig-
ure 2 on page 7. The forward center of gravity limits are
fixed by structural strength. The elevator control for these
forward limits is good for all normal operations. The most
rearward center of gravity limit is determined by the longi-
tudinal instability which occurs at climbing power. Going
aft of this limit will make the airplane very difficult to fly
and will decrease the safety of the airplane. The center of
gravity position has little, if any, effect on the range and
speed of the airplane. However, it must be properly con-
trolled for safe and easy flying. Every possible effort must
be made to keep the center of gravity within the design
limits and to keep the gross weight of the airplane to the
absolute minimum for the mission to be performed. Using
a weight and balance slide rule before and during every
flight will help improve the airplane's usefulness.
More About Stalls
The stall characteristics of the B-29 airplane are entirely
normal. As the stall is approached a very noticeable lighten-
ing of the elevator loads will occur. It will be necessary to
move the controls an appreciable amount to get a response
from the airplane. Just before the full stall is reached, a
shuddering and buffeting of the airplane will occur. The
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airplane will recover from the stall very normally and no
excessive wing dropping will be encountered when the stalls
are properly controlled. Power reduces the stalling speed
but, in general, has no large effect upon the stall. Never fly
below the power-off stalling speed since any loss in power
when flying below this speed is liable to stall the airplane.
Very violent stalling of the airplane might be encountered
during these conditions. On all landing approaches extreme
care should be taken never to allow the speed to fall below
the power-off stalling speed. It might be well to try power-
off approaches whenever possible in order to become familiar
with the airplane under emergency conditions. Power should
never be used in order to reduce the landing speed.
When the airplane is stalled, recovery should always be
made by nosing the airplane down. This should then be
followed with more power. However, never apply power at
the stall without dropping the nose at the same time. In most
airplanes, it is possible to obtain a very high rate of descent
in a power-stall by applying power during the power-off-stall
without dropping the nose. These conditions must be
avoided in the B-29.
Power Off Stalling Speeds
Gross INDICATED STALLING SPEEDS
Weight Flaps up Flaps 25° Flaps_Full
140,000 145 131 119
130,000 140 126 114
120,000 135 121 110
110,000 129 115 105
100,000 123 110 100
90,000 117 104 95
80,000 110 98 89
70,000 103 92 84
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Performance 1
The B-29 is capable of being loaded to very high weights
and the effect of such weights upon the airplane performance
is very large. The rate of climb, takeoff distance, and other
such characteristics of the airplane are excellent at light gross
weights. As the weight increases these characteristics grad-
ually change and at the highest weights some of the air-
plane's performance characteristics become poor. The weight
to which the airplane may be loaded depends primarily upon
the ability of the crew to get the best from the airplane. The
maximum weight of the airplane is therefore limited only by
performance and it is of the utmost importance that it be
properly controlled. Even at weights below the maximum,
all equipment not necessary for a given mission and which
is readily removable from the airplane should be removed
for that mission. Every pilot knows that for each pound re-
moved, one more pound of fuel or bombs can be added; or
that the performance will be improved at lighter gross
weights. Incidentally, the maximum altitude for any mission
can be increased one foot for every two pounds removed
from the airplane.
The cowl flaps have a very large effect upon the drag
of the airplane. Changing the cowl flap position from closed
to 4½ inches open raises the drag of the airplane 50% at high
speeds. This effect is quite important at high speed but it is
equally important in getting maximum climb performance
under emergency conditions. The cowl flaps should always
be kept to the smallest opening possible while still retaining
engine cooling. At the larger cowl flap openings some buf-
feting will be encountered as well as a change in longitu-
dinal trim. The cowl flap openings that cause buffeting are
inefficient and do not give very much better engine cooling
than the largest opening which does not give buffeting.
Besides that, buffeting should never be tolerated. This is
particularly true in level flight.
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In level flight, the use of more than 3" cowl flap opening
will have no effect upon engine temperatures but will have
a very large effect on airplane speed. Each inch of cowl
flap opening drops the airplane speed 10 MPH, I.A.S., or
raises the power-required 10%. In a IO-hour flight at 15,000
feet altitude, each inch of cowl flap opening raises the fuel re-
quired for this flight by 350 gallons. It is therefore extremely
important to keep the smallest possible cowl flap opening
for all flight conditions.
Of course, it is equally important to keep the power
plant in good mechanical condition so that the engine will
not run hot. One very important item to check is the seal
between the engine baffles and the ring cowl. Never allow
any leakage of air through this seal. The seal should be
checked frequently to make sure that air loads during flight
do not deflect the seal and allow it to leak.
During all normal flying conditions, the pilot will find
no difficulty in controlling the airplane under any conditions
of symmetrical power. However, there is a range of speeds
near takeoff speed where the control is difficult or nearly
impossible when the power is not the same on bot~ sides of
the airplane. If the airplane is flown with high power on
three engines and with the other engine windmilling, there
will be a strong tendency for it to roll and yaw. This yaw
can be permitted, but it will require the use of the aileron to
keep lateral trim. The airplane will then fly in a crabbing
manner. By using rudder, the airplane can be made to fly
straight under this unsymmetrical power condition. If this
maneuver is tried at lower and lower speeds, there will be
more and more crabbing as the speed drops and then more
rudder will be needed to stop this crabbing.
When flying at light gross weights at a speed of around
120 MPH, I.A.S., it will take full rudder to just keep the
airplane from crabbing when an outboard engine is dead.
Page 10
. I
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If the speed is allowed to drop below this point the airplane
will start to crab still further and it will be impossible to
stop the crabbing even with the rudder hard over. As the
crabbing becomes worse, it will be necessary to use more
and more aileron to get lateral trim. If this speed is still fur-
ther decreased, the point is reached where full rudder and
full aileron are used. At any speed below this point, it will
not be possible to get lateral control and the airplane will go
into an uncontrolled roll. This can be prevented only by
reducing the power on the outboard engine opposite to the
dead engine side or by flying faster.
It is possible to fly with two dead engines on the same
side and still get good control down to 130 MPH, I.A.S. at the
lower weights. The two dead engines must have their props
feathered. Recent flight tests have shown that the airplane
will not be able to maintain altitude except at the very light-
est gross weight when two engines on one side are at rated
power and the other two have their props windmilling. The
drag of two windmilling props on one side increases the air-
plane drag 60% at all speeds. Feathering practically elimin-
ates this added drag.
All stalling speeds will go up at the higher gross weights.
Lateral control with unsymmetrical power can not be ex-
pected to be good at the stalling speed. In general, the pilot
should always stay at least 10 MPH, I.A.S., above the power-
off stalling speed. Consult the stalling speeds shown in the
table in the cockpit before the need comes to fly with un-
symmetrical power. It is expected that this airplane, like any
other airplane, will make very violent, possibly destructive,
maneuvers if stalled while flying with any appreciable
amount of unsymmetrical power. The ability of the airplane
to fly on two engines, even with these engines at military
power, is very limited at high weights. Large cowl flap set-
tings, extended landing gear, and deflected wing flaps will
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greatly reduce the rate of climb of the airplane. At 100,000
pounds gross weight, it is just possible to maintain level flight
on two engines with two propellers feathered and with the
landing gear down and flaps in the approach position. At
130,000 pounds a very nearly similar condition exists when
flying on three engines at military power. It is therefore nec-
essary to keep the drag of the airplane as small as possible
at all times and especially when flying at high weights. The
landing gear and flaps must be retracted as soon after take-
off as feasible and they must not be extended for emergency
landing until the landing is assured because the performance
will probably be so marginal with one or more engines dead
that only one try at landing can be made once the flaps and
gears are down. The best rate of climb under these critical
conditions of flaps and gear down will be for speeds 10
MPH, I.A.S., above the power-off stalling speed and in any
case not below 120 MPH, I.A.S. Any closer approach to the
stalling speed may cause a loss of lateral control when fly-
ing with unsymmetrical power.
Dive Speeds
The airplane is limited in its diving speed by both
strength and by control characteristics. As the speed is in-
creased the loads carried on nearly all parts of the airplane
increase very rapidly. This is especially true of the horizontal
tail surfaces. The present airplanes are placarded to not ex-
ceed 300 MPH, I.A.S. This placard speed was chosen to be
far enough above the level flight high speed of the airplane
to cover most of diving needs of this airplane. The airplane
has not been dive tested to higher speeds and contains a num-
ber of questionable items which may cause trouble at speeds
above 300. For this reason the placard dive speeds should
never be exceeded. It is expected that all placard speeds
will be increased in subsequent airplanes after they have
been fully investigated. At high altitudes it is necessary to
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keep the diving speed below 300 MPH, I.A.S. in accordance
with the values marked on the placard around the airspeed in-
dicator. This reduction in speed is required in order that un-
satisfactory longitudinal control will not be encountered in
diving at high altitudes. During high dive speeds at altitude
various compressibility effects can be expected on the air-
plane such as buffeting of the wing and the tail, extremely
large elevator trim changes, and even control ineffective-
ness.
A THING OR TWO
TAKING OFF
The B-29 takeoff distance is about the same as that of the
B-17 and B-24. The speed at which the airplane is pulled off is
very important. A high takeoff speed means a long takeoff
distance because the time to raise the speed above the nor-
mal takeoff speed is longer and the rate at which the airplane
covers the ground is greater. Extending the flaps to 25° will
raise the drag during the run but the flaps will also increase
the wing lift and therefore take load off of the wheels which
in turn decreases the wheel rolling-drag. The resulting net
drag is not changed much but the takeoff speed is consid-
erably reduced with 25° flaps. More than 25° flaps results in
takeoff losses. Figure 3 on page 14 shows how the distance
goes up with speed and how the flaps affect the run. It can
readily be seen that the best procedure for a short takeoff is
to get off at a low speed. Lower the tail easily near 90 MPH,
I.A.S. so that the airplane lifts off the ground as soon as it has
flying speed. Some longitudinal instability will be noticed
during the run below 90 MPH, I.A.S., before the elevators
become very effective. Some pilots like to hold the airplane
with the wheel brakes until the throttles are nearly full
open and then release the brakes, thereby helping to cut
down the takeoff distance.
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Once off the ground, the shortest distance to clear ob-
stacles may be covered by not allowing the speed to in-
crease too much. Tests have shown that the speed can be
held down to 10 MPH, I.A.S. above the takeoff speed without
getting into any control difficulties. The speed in the climb-
out must, of course, never be allowed to drop below the
takeoff speed.
The landing gear should be retracted as soon as possible.
Because of the aerodynamic cleanness of the airplane, the
landing gear drag on the B-29 is relatively much greater than
on the B-17 and B-24 airplanes. Pulling the gear up is equiva-
lent to adding more power. At high gross weights, therefore,
power should not be reduced until the gear has been re-
tracted.
Flaps should be retracted when the speed is 40 MPH,
I.A.S. higher than takeoff speed. The power-off stalling speed
with the flaps up is 15 to 20 MPH, I.A.S. higher than the
lowest takeoff speed with 25° flaps at any weight, so a mar-
gin of 20 to 25 MPH, I.A.S. above flaps-up stalling speed
must be held when retracting the flaps. The maximum al-
lowable speed with 25° flaps is 220 MPH, I.A.S.
Takeoff instructions for the B-29 are included in the
cockpit operational charts in all airplanes. These instructions
are based on actual flight operation and they will probably
be modified in the future when more is learned about the
airplane. They are also given here:
(1) On runup set 2600 RPM and 47.5 inches manifold
pressure.
(2) Set wing flaps to 25° and cowl flaps full open (4½
inch gap).
(3) Set elevator trim tab neutral.
(4) At 2600 RPM and 47.5 inches accelerate to 90 MPH,
I.A.S., with nose wheel on the ground.
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(5) Lower tail gradually and continue acceleration to
takeoff speed.
(6) Climb over obstructions at 140 MPH, I.A.S.
(7) Retract landing gear as soon as convenient.
(8) Retract flaps when convenient above 500 ft. and 160
MPH,I.A.S.
(9) At high weights do not reduce power below 2600
RPM and 47.5 inches until gear is retracted.
(10) Minimum speed for two engine control is 130 MPH.
These instructions are for the usual longer takeoff and in
order to make them good for a short takeoff the sixth step
should read, "Climb over obstructions at 10 MPH, I.A.S.
above takeoff speed."
The operation of the cowl flaps is important. They must
remain wide open during the ground engine run-up and held
to 4½ inches of opening in the takeoff. These settings will
give satisfactory engine cooling which is extremely import-
ant and must be watched closely.
The tailskid on the B-29 airplane is arranged to prevent
taking off at too low an airspeed. The minimum possible
takeoff speed is just about the power-off stalling speed and
well above the power-on stalling speed. The tailskid is de-
signed to be used, and minimum distance takeoffs will be
obtained by holding the tailskid to the ground as takeoff
speed is reached. After leaving the ground in this manner it
is extremely important to keep the airspeed above takeoff
speed.
CLIMBING
The best climbing speed is 195 MPH, I.A.S. under or-
dinary conditions and at all weights. The speed of 195 MPH,
I.A.S. is a compromise. It was chosen to give the maximum
rates of climb at high gross weights and to give good en-
gine cooling at low gross weights. The rate of climb at low
Page 16
RESTRICTED
gross weights will be more than sufficient even though this
speed is higher than the best. The speed for best climb
with two or three engines in operation is 180 MPH, I.A.S.
The B-29 rates of climb at rated power are nearly the same
as for the B-17 and the B-24 when the B-29 weighs twice as
much as they weigh. This is reasonable since it also has
twice their power. The B-29 will cover a greater distance in
the climb. The time to climb to any altitude will be roughly
the same.
On average days (about 60° F. on the ground), climb the
airplane at 195 MPH, I.A.S. with 2½ inches cowl flap gap. On
a hot day (about 100° F. on the ground) climb 10 MPH, I.A.S.
faster with one inch more cowl flap opening (205 MPH, I.A.S.
with a 3½ inch opening). Nothing is gained by opening the
cowl flaps wider than 3½ inches. If the cowl flaps are opened
one more inch than necessary, the rate of climb will drop 100
ft. per minute with no appreciable drop in cylinder head tem-
perature.
The best engine operating temperatures in climb are
248° C. (measured at the cylinder heads), but it must be re-
membered that the temperature indicators cannot be ex-
pected to be accurate to within 15°C. The above speeds and
cowl flap settings should be sufficient for cooling under all
conditions. Use the automatic oil cooler control and use ½
open intercooler opening, except at high temperatures use
full opening.
To obtain maximum climb performance, particularly at
high weights, climb at rated power, 2400 RPM and 43 inches
M.P. For normal operations where high rates of climb are
not important, it is probably easier on the engines to climb
at 2300 RPM and 39 inches.
LEVELING OFF AND GOING PLACES
Level flight is the easi.
est part of flying, but even here
there are some things which need to be understood very
clearly.
Page 17

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In order to know how the power needed to fly changes
as the speed changes, it is necessary to understand how an
airplane uses power. Assume that an airplane is in level
flight. It requires power to keep flying. Some power is used
to keep just the airplane afloat in the air. The second part of
the power pulls the airplane through the air. These portions
change as the airplane changes its speed. When it is flying
slowly, a lot of power is used to support the airplane and
very little of it is used for moving. Then as the speed in-
creases, less and less power is used to keep the airplane in
the air and more power goes into pulling the airplane. Fig-
ures 4, 5 & 6 are curves drawn to show these effects. See
pages 19, 20 & 21.
The power required curve in Fig. 7, page 22, shows that
after the speed gets fairly high, raising the power will raise
the speed. However, at low speeds (below 170 MPH, I.A.S.
for the B-29), it is possible to use more power and yet get
less speed. It is easy to fly for hours on the "back side of
the curve" when this happens. It takes only a momentary drop
of the airplane's nose to boost the speed 20 to 30 MPH, I.A.S.
with the same power.
Sometimes pilots have had trouble in rough air when
they tried to hold the altitude constant when flying near the
bottom portion of the curve. The speed changed 20 to 30
MPH, I.A.S. They were flying first on the "front side" and
then on the "back side" of the curve. If they had held the
speed constant, instead of the altitude, flying would have
been easier and the altitude would not have changed too
much.
More power is required to fly when the airplane's weight
increases. Adding 100 pounds requires from 2 to 3 more
horsepower to fly the B-29 level at a set speed in the medium
speed range. One more horsepower per 100 pounds is
needed at higher flight speeds.
Page 18
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Page 20 Figure 5
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Then adding these parts and calling the curve "Power-
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The B-29 and B-17 Power-Required Curves are shown
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Page 22 Figure 7
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The effect of altitude on the speed and power combina-
tion must also be recognized. If the power is held constant,
the level flight speed will drop off at the rate of 1½ MPH,
I.A.S. for each 1000 feet increase in altitude but the true air
speed will increase 1%.
The previous discussion of the effects of cowl flap open-
ings needs to be emphasized further when the airplane is
flying level. To get the best performance, this is the way to
operate the cowl flaps:
A. On an average day (60° F. on the ground).
1. OPEN COWL FLAPS ½ inch when between sea
level and 10,000 feet.
2. OPEN COWL FLAPS 1 inch when between 10,000
and 20,000 feet.
3. OPEN COWL FLAPS 2 inches when between 20,-
000 and 30,000 feet.
B. On a hot day (100° F. on the ground).
1. OPEN FLAPS ONE MORE INCH AT EACH ALTI-
TUDE SHOWN ABOVE.
These openings will give satisfactory engine cooling.
Never exceed 3 inches of cowl flap opening in level flight.
As the head temperature gauges are only accurate to plus or
minus 15° C, the above openings should be used instead of
adjusting cowl flaps to obtain a given temperature. The head
temperature gauge should be watched to be sure that the
engines are not overheating excessively.
The intercooler cools the air entering the carburetor. For
normal operation, the best setting is half open. When the
engines are operating at high powers in hot weather, the in-
tercoolers should be wide open.
The temperature of the engine oil is controlled auto-
matically and unless mechanical trouble is present, the oil
temperatures will require no attention.
Page 23

RESTRICTED
Speeds from the airspeed indicators need several large
corrections for finding true airspeeds. There is a correction
which must be made for the attitude of the airplane; one for
the effect of compressibility, a large one or the air density at
altitude, and one for temperature.
All of these corrections have been taken into account
in the chart in Figure 8, page 25, which should be used direct-
ly in converting the airspeed indicator reading to the true
airspeed.
To use the chart start at the upper left corner with the
indicated airspeed which the indicator shows. Follow direct-
ly downward from this speed to the diagonal line of the alti-
tude at which the airplane is flying. Then follow straight
to the right to the diagonal line of the temperature (OAT) of
the outside air. From this temperature line follow directly
downward to the true airspeed scale on the lower left of
the chart and read the true airspeed.
For example if the airspeed indicator shows 220 MPH,
I.A.S. while flying at an indicated altitude of 25,000 feet where
the outside air temperature is -30° C., enter the chart at 220
MPH, I.A.S. at (a), follow the arrows to 25,000 feet at (b), then
to -30° C. at (c) and finally to the 318 MPH true airspeed at (d).
Since the compressibility and airplane attitude correc-
tions incorporated in this chart are for the B-29 only, this en-
tire chart is for the B-29 and no other airplane.
Figure 9 on page 26 shows how the drag of various parts
of the airplane contribute their share in drag. As an example,
at 150 MPH, I.A.S. with the flaps and landing gear down, the
drag added to the airplane is almost 1½ times the drag
when everything was retracted. The total drag becomes 2½
times as large. Adding up the drags for 220 MPH, when
the airplane has the flaps down 25°, landing gear fully ex-
tended, and cowl flaps opened 4½ inches; the drag is almost
3 times what it was when everything was retracted.
Page 24
RESTRICTED
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Any other combinations can be found by adding differ-
ent amounts of the items that contribute to the drag.
GETTING MAXIMUM ENDURANCE
The way to stay in the air the longest possible time is
to fly at the speed where the engines use gasoline at the
slowest rate. That happens when the smallest amount of en-
gine power is used to keep flying. Going back to the Power
Required Curve shown in Figure 6 on page 21, it can be
seen that the bottom of the curve is the place where the
least amount of power is used for level flight.
Part of that curve is repeated here to help show a little
more of what the curve means.
C
AIRSPEED
Point C is the place where the power is the least. To reduce
the chances of flying first on the "front side" and then on
the "back side" of the curve, the B-29 endurance speed was
chosen to be a little way up the "front side" away from the
bottom point. The speed is 170 MPH, I.A.S. for airplane
weights up to 100,000 pounds and 190 MPH, I.A.S. for weights
Page 27

RESTRICTED
above 100,000 pounds. Actually, the B-29 endurance speed is
much higher than the B-17 long range cruising speed. To get
good performance, the airplane must be flown at a constant
indicated airspeed and this means that the power must be
adjusted to maintain altitude.
The less the airplane weighs and the lower the altitude
flown, the longer the airplane will stay in the air.
Maximum endurance can be obtained by trimming the
airplane for the best speed and dropping below the usual
cruising power by reducing RPM and holding the manifold
pressure to 28 inches (plus or minus 2 inches). When less
power is desirable, hold 1400 RPM as the absolute minimum
and then throttle the engines to lower manifold pressures.
The main reason for this is to avoid losing current from the
generators on the engines when flying at low RPM's.
Point A on the curve shows where altitude would in-
crease as the speed is decreased steadily while holding con-
stant power, whereas if the speed was increased, there would
be a drop in altitude. At point B the reverse is true. A slow
steady decrease in speed here actually lowers altitudes. These
are the reasons for saying that the pilot must hold airspeed
constant by nosing the airplane down when necessary to pick
up speed and control altitude with changes in power. Ob-
viously, sudden maneuvers of the airplane are not the things·
to do when the main object is to stay in the air a long time.
The warnings on cowl flap operation under level flying
apply here and they should never be forgotten.
GOING A LONG WAY
The B-29 is built to do one particular job well: To fly
a long way with a big load of bombs. It has excellent abilities
to fly fast and high, but its outstanding tactical ability is long
range bombing.
Maximum range is flown at the speed and altitude that
give the greatest mileage from each gallon of gasoline con-
Page 28
RESTRICTED
sumed. This is a higher speed than that for maximum en-
durance. Adding a little more power to the minimum power
needed to stay in the air (which also increases fuel flow)
produces a fairly large increase in speed and therefore an in-
crease in miles traveled for each gallon of fuel used. As the
power is increased further and further, both the speed and
the fuel consumption are increased. There is one range of
speeds in this process where the speed has increased the
most while the rate of using gasoline has not increased too
much. The middle of this range is about 15 MPH, I.A.S.
above the minimum power speed. Going above this speed,
the airplane gets fewer miles per gallon of gasoline. Actually,
it works out so that there is a fairly wide speed band within
which maximum miles per gallon can be obtained. This speed
band is normally at least 15 MPH, I.A.S. wide in terms of in-
dicated airspeed.
If the airplane is flown within this speed band, maxi-
mum range will be obtained. The lower portion of this band
is very difficult to use in "formation" and there is no reason
to fly at a low speed when a higher one will carry the air-
eo,ooo#
so,ooo#
100,ooof
110,000#
120,000#
LONG RANGE CRUISING
SPEED BAND
25,000 FT. ALTITUDE
140,000#
INDICATED AIRSPEED
MPH
AIRSPEED VS MILES PER GALLON
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Page 29

RESTRICTED
plane just as far and will do it in a shorter time. A headwind
decreases the range by its MPH value for every hour the
airplane flies. A greater range will be obtained when flying at
the higher end of the speed band in a headwind. For this
reason, cruising instructions are given for the upper five
MPH portion of this band. The weight of the airplane ma-
terially affects the speed but altitude has no effect upon
the indicated speed at which maximum range is obtained. The
speeds for maximum range are shown in Figure 10, page 29.
Gross Weight Indicated Airspeed
80,000-90,000 lbs.
90,000-100,000
100,000-110,000
110,000-120,000
120,000-130,000
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GROSS WT. - THOU SANDS OF POUNDS
INDICATED AIRSPEED VS GROSS WEIGHT
Page 30 Figure 11
70
RESTRICTED
When flying for maximum range, the speed should be
held within this speed band. The power should be obtained
by adjusting RPM while holding the manifold pressure to 28
inches (plus or minus 2 inches) and auto lean at 2100 RPM
(and below). When in formation, the formation leader should
hold the speed at the bottom of the band in order to allow the
other airplanes, which will have some changes in speed, to
stay within the economical speed band.
Maximum range is obtained at low altitudes. If operation
at powers of 2100 RPM and 31 inches in auto lean (or less)
can be accomplished in the desired speed band, there will
be no gain in range by flying at a lower altitude. The range
loss at high altitudes is caused almost entirely by the rich
mixtures required at high powers and the larger cowl flap
openings needed to cool the engines at high altitudes. In
general, there will be no loss in range up to 15,000 feet alti-
tude. The range losses at higher altitudes occur almost en-
tirely when flying at the highest weights. They can be
avoided, to a considerable extent, by flying at low altitudes
until a moderate weight is obtained and then climbing to a
higher altitude.
To obtain maximum range it is necessary to control the
airplane drag and weight. For each 6 pounds added to the
empty weight of the airplane, it is necessary to add one gal-
lon of gas to get the same range. This increases the gross
weight 12 pounds. Each inch of cowl flap opening used above
that required to cool the engines will increase the fuel used
by at least 35 gallons per hour. The airplane is very 9lean and
is affected considerably by added drag. Everything added
to the outside of the airplane, whether it is streamlined or
not, will add drag and decrease the range and maximum
speed. KEEP YOUR AIRPLANE CLEAN AND LIGHT. KEEP
THE COWL FLAPS AS NEARLY CLOSED AS POSSIBLE AND
USE AUTO LEAN IF ENGINE POWERS PERMIT. USE REC-
Page 31

RESTRICTED
OMMENDED AIRPLANE SPEEDS AND ENGINE POWERS.
(Figure 15, page 47, for recommended power settings.)
If the airplane has difficulty in keeping up with the
others, it is probably due to extra drag or extra weight. On
Figure 12, page 33, the powers required by three airplanes are
shown. Do not be one of the airplanes which takes more
power and gas.
To extend the maximum range, the descent should be
made with the recommended long range cruising speeds and
the lowest recommended power setting at the end of a long
range flight.
FLYING IN FORMATION
Skillful flying in large formations requires the pilot to be
alert at the controls at all times. To foresee and anticipate
each movement of the formation calls for teamwork. Smooth
operation of the pedals and wheel are important. Each mem-
ber's motion in the team depends on the changing speeds of
the others in the formation ahead. The tendency to overrun or
fall behind must be overcome by anticipating the action of
the airplane and the others in the formation. For increasing
speed there are two methods at the pilot's command: First,
to increase the power; and second, to dive the airplane
slightly. For decreasing the speed, reduce the power or
climb the airplane. NEVER USE the cowl flaps, wing flaps, or
landing gear to increase the drag for slowing down.
In some cases, it will be necessary to increase power. In
formation flying, the lead plane must set up the cruising
conditions according to the operating charts. The bottom
end of the long range speed band, explained under long
range flying, is the correct place for the lead plane. The
wing planes should set their RPM from 100 to 200 higher
than the lead plane at manifold pressures recommended for
these RPM's and then reduce the manifold pressures with
Page 32
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Figure 12 Page 33

RESTRICTED
the boost control to get the desired speed. Power should be
adjusted by the boost control with full throttles. The mixture
conrol should be set the same for all airplanes and it should
be the setting recommended for the power setting of the
lead airplane except when the lead plane is using 2100 RPM
or greater; then it should be automatic rich.
The response of the airplane to changes in power varies
considerably with different loadings and different altitudes.
Supposing a formation of B-29's, average weight of 105,000
pounds, is cruising for a long range at 25,000 feet altitude, and
after a maneuver, one airplane finds itself 100 yards behind
its assigned position. In order to catch up, the pilot may
apply rated power. The total time for him to gain 100 yards
and get back into position will be 35 seconds. Under similar
conditions, he would be able to repeat the same maneuver at
5000 feet in 25 seconds. The reason for the difference in time
is that there is more power available to use in accelerating at
low altitudes than at high altitudes since less of the available
power is required to cruise at low altitudes than at high alti-
tudes. When flying with 130,000 pounds at 25,000 feet, it will
be difficult to accelerate the airplane rapidly.
Changes in altitude are helpful in changing the speed
only when the change is needed momentarily. For instance,
if a very large formation makes a turn where inside planes
must slow down and the outside planes must speed up, the
outside planes can gain speed by diving slightly and the
inside planes can lose speed by climbing slightly. Coming
out of the turn, the outside plane may still have too much
speed and that can be eliminated by climbing a little more.
However, the wing planes will not be able to get back to
their former level until a turn is made in the opposite direc-
tion. Such a procedure may not always work; but it should
be used, if at all possible, for such maneuvers as flak evasion.
It is believed that better fuel consumption can be obtained by
Page 34
RESTRICTED
this procedure. A gain on loss in altitude of 100 feet will mo-
mentarily drop or pick up speed from 3 to 5 MPH, I.A.S. Of
course, such altitude changes can only be used in very large
or reasonably open formations.
EMERGENCIES IN FLIGHT
At Takeoff
The previous discussion on takeoff emphasized the short
field takeoff. However, when there is plenty of runway and
there are no obstacles to clear, higher takeoff speeds are
safer. 25° wing flaps should still be used. This is especially
true when considering the possibility of an outboard engine
failure. When this happens, there will be an immediate loss
of lift over the section of the wing back of the dead engine
due to the loss of its slipstream. In addition to this effect, the
loss in thrust plus the prop windmilling drag will tend to
make the dead-engine wing drop. Rudder and aileron must
immediately be applied to counteract this tendency. How-
ever, if the airspeed is too low, the control surface will not
have enough effect to counteract the yawing and rolling ten-
dency and the result will be an airplane out of control. The
airspeed at which control becomes insufficient, when an out-
board engine fails, is 120 MPH, I.A.S. Failure of an inboard
engine will be less critical than an outboard, but this speed
should be respected in all cases.
If an engine fails during the ground run below a speed
of 120 MPH, I.A.S., do not take off unless a speed of 120
MPH, I.A.S. can be reached (using three engines on the take-
off run) before getting to the end of the runway, and unless
all obstacles can be cleared. If an outboard engine should
fail in the climb-out at an airspeed below 120 MPH, I.A.S.,
airspeed must be gained rapidly by nosing the airplane
down even though close to the ground and control retained
by partial throttling of the opposite outboard engine. When
120 MPH, I.A.S. is obtained full power may be used. Any at-
Page 35

RESTRICTED
tempt to climb the airplane before this speed is reached will
be disastrous. The landing gear should be retracted as soon
as possible in all cases after the airplane has left the ground.
If a propeller runs away on takeoff, it will probably be
due to a failure of the governor; and the propeller controls
will do no good. Power should be reduced immediately with
the throttle sufficiently to bring the RPM down well below
2,800. This will get some power from that engine for takeoff
but as speed is increased the help from the runaway engine
will be less. At 150 MPH, I.A.S. it will be dragging rather than
producing thrust. A landing should be made as soon as pos-
sible.
If a turbo runs away, manifold pressure will become ex-
cessive. This will most likely be due to boost trouble or a
jammed wastegate and a reduction of boost setting will
probably do no good, but ,will only reduce power on other
engines. Reduce manifold pressure on the runaway engine
immediately to 40" with the throttle. This will prevent turbo
overspeed and yet will provide sufficient power to complete
the takeoff.
Full military power on all 4 engines is required for cor-
rect takeoff. Less total wear and tear of the powerplant re-
sults. Using less power is just asking for trouble. UNDER NO
CONDITIONS WHATEVER IS IT CONSIDERED DESIRABLE
TO TAKE OFF FROM A STANDSTILL WITH AN ENGINE
INOPERATIVE OR FEATHERED.
Level Flight
Flying above level flight high speeds through very gusty
weather such as thunderstorms may overload the airplane's
structural backbone. Up and down gusts around 30 MPH,
I.A.S. have been measured in heavy cumulus clouds. The
B-29 will not be in danger from gusts or excessive maneuver-
ing no matter what its weight might be or at what altitude it
might be flying if the speed does not go over 220 MPH, I.A.S.
Page 36
RESTRICTED
The long range cruising speeds are about the safest speeds
for all conditions. The safest flying is away from storms.
The B-29 propeller feathering system uses engine oil
pumped by an electric motor into the propeller dome. If a
damaged engine loses oil to the extent that there is a drop in
oil pressure, a 3 gallon oil reservoir will stipply oil for feath-
ering, unfeathering, and feathering once more. After that the
oil suply may be too low for the pump to furnish the oil re-
quired for feathering. (An airplane that has this reservoir
can be identified readily by checking the location of the
feathering pump. If it is in the accessory compartment be-
hind the engine the airplane is not up-to-date, and there is
no reservoir. If the pump is under the oil tank, the airplane
will have the 3 gallons available for feathering.) Propeller
governing will stop soon after that, since governing also uses
engine oil. At this time the propeller blades will go to their
lowest pitch due to centrifugal force. The prop will then
''windmill'' in low pitch.
The speed with which the props windmill will depend
upon the airspeed and the altitude. Rotation will be faster at
high altitudes and high speeds. The windmilling props will
- tend to follow the true airspeed instead of the indicated air-
speed. The approximate RPM at which a propeller will ro-
tate at different airspeeds and altitudes is shown in figure
13, page 38.
The chart shows that at 180 MPH, I.A.S., the windmilling will
be around 4200 RPM at 35,000 feet, while at 5000 feet it will
only be slightly over 2600 RPM.
Since very high windmilling speeds will cause cen-
trifugal explosion of the propellers or destruction of the en-
gines, it is necessary to reduce the speed enough to avoid
failure. On the other hand, quick reductions of airspeed by
means of pull-ups must be carefully avoided, since an inad-
vertent stall with a dead engine may occur at a high speed
Page 37

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4000
~ 3600
n.
ct:
3200
2800
2400
2000
1600
140 160 180 200 220 240
INDICATED AIRSPEED-MPH
APPROX. PROPELLER WINDMILLING SPEED
Figure 13
and will be much more severe than the symmetrical power-
stall. Indications are that the props may rotate at somewhat
over 4000 engine RPM for a short time without destroying
the prop or engine. It is believed that an exploding prop at
high altitude might be less hazardous to the airplane and
crew than a dead engine stall.
Therefore, at all altitudes, throttle the engines complete-
ly and reduce the airspeed slowly to 160 MPH, I.A.S. This
procedure will avoid both the stall and the possibility of an
exploding prop at altitudes as high as 35,000 feet. If vibration
or some other trouble makes further speed reductions nec-
essary, the flaps should be lowered. In any case, the altitude
should be reduced as soon as possible but always without
getting high air speeds by diving. At low altitudes, cruising
Page 38
RESTRICTED
speeds may again be maintained for the flight back to base,
without causing trouble from windmilling.
For straight level flight with one engine feathered, the
flight of the B-29 seems little different from 4 engine flight.
There may even be a temptation to maneuver and handle
the airplane in the same way with a dead engine. To be safe
in turning into a dead engine to the extent of 180° a minute
(approx. 1 needle width on the flight indicator), the speed
must be at least 20 or 25 MPH, I.A.S. above the power-off
stalling speed of the airplane. To avoid trouble never turn
into a dead engine even at only one needle width or at any
altitude at less than 150 MPH, I.A.S. For steeper turns or
high weights, the speed should be higher.
If two engines are out on the same side the crabbing
spoken of on page 35, becomes worse. The minimum air-
speed will be accordingly higher and it will also be harder
to maintain.
GLIDING
The range of the airplane can be extended by starting the
descent at the proper time. Present knowledge of the air-
plane indicates that a moderate rate of descent at the level
flight cruising speed will be the best. In all cases, the im-
portance of holding the airspeed cannot be overstressed.
To obtain a high rate of descent in the glide, where glide
stretching is not required, close the cowl flaps and throttle
the engines. Glide at 220 MPH, I.A.S. Clear the engines
thoroughly when any sudden power requirements are an-
ticipated. If a still higher rate of descent is required extend
the wing flaps or landing gear and be sure to observe their
placard speeds.
LANDING APPROACH
At the beginning of the approach, the flaps should be
down to 25° and the speed should be 160 MPH, I.A.S. Keep
the gear up until the landing is a "sure thing." Allow one
Page 39

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minute in which to lower the landing gear. Then the final
approach should be 30 MPH, I.A.S. above the power-off
stalling speed with the flaps all the way down. Set the boost
control full-on and set the RPM to 2100 RPM.
It is very important not to reduce power rapidly during
any part of the approach. Never allow the speed to fall below
the power-off stalling speed even when landing.
LANDING
The correct landing approach will make the landing
simple. The flaps should be full down by the time the air-
plane reaches the edge of the field. Don't lower the flaps
completely until the airplane's speed is down to 180 MPH,
I.A.S. Any higher speed will damage, if not destroy, the
flaps. The airplane should be flared rapidly just before con-
tact and then the airplane should land on the main wheels
with the tail low. Some pilots prefer to bring the airplane in
so that the tail skid touches first. If done properly, this method
is quite satisfactory. The airplane has been designed to with-
stand inadvertent 3-point landings on the main wheels and
nose wheel and no difficulties will be encountered when the
airplane weighs 120,000 pounds and the impact on the three
wheels is 2.7 times that weight (2.7 G's).
Brakes should be applied after the nose wheel has
touched the ground. Be careful to keep the tires from skid-
ding "or they won't last long". Besides that, an airplane skid-
ding on the ground is uncontrollable.
One thing more might be mentioned here before the air-
plane comes to a stop in its roll. It is the opinion of some
pilots that the pilot's chair should be adjusted so that there
will be at least 2 inches of clearance between the pilot's hand
and his leg when the stick is back and the wheel is turned.
This will allow complete freedom of movement in case of an
emergency when landing.
Page 40
Refused Landing
RESTRICTED
EMERGENCIES IN LANDING
The technique to be used for a refused landing is not
complicated. Flaps should be raised from full-down position
to 25° immediately after full power is·applied. Continue on
the same approach angle until a safe flying speed is reached.
Raise gear as soon as it becomes apparent that the rnnway
will not be touched. Flaps and gear should be raised together
if at least 3 generators are functioning. Raising the flaps im-
mediately to 25° is of paramount importance rather than wait-
ing for a "safe airspeed" as a "safe airspeed" will never be
reached as long as the flaps are full-down due to the high flap
drag and the reduced acceleration with the possible operation
on three engines.
A "go-around" should not be attempted on less than
three engines.
Short-Field Landing
Fundamentally, there is no important difference in the
emergency landing technique of the B-29 and that of other
airplanes such as the B-17.
The approach should be the same as for the normal ap-
proach but a somewhat slower landing may be made with a
low-angle power approach and. also better selection of the
point of landing is possible. Using a landing speed of 100
MPH, I.A.S. at 100,000 pounds, and full brakes, requires 1300
feet of runway for stopping. After contact the brakes should
be used as soon and as hard as possible without banging the
nose wheel to the ground or skidding the tires. The actual
ground contact may very likely be tailskid first under these
conditions, and this will not be dangerous. If the flaps are
retracted after contact the full braking power may be used
with less tendency to skid the tires and this will give a shorter
roll.
If the terrain is either too rough for a successful wheel
Page 41

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landing or too soft to support the airplane's weight, the air-
plane should be landed on its belly. The technique for a belly
landing is not greatly different from the ordinary landing, but
the behavior of the airplane is very much different because
the drag of the landing gear is large. The proper approach
angle to the normal landing is quite well determined and
pilots soon learn the amount of power and rate of descent to
to get this approach with the gear down. Unless this is taken
into account in a belly landing, the rate of descent will be
too high for the same flight path angle and excess speed will
result in severe overshooting of the intended landing point.
Approximately the ·same approach and landing speeds should
be used for the belly landing as for the wheel landing, but
this will require less rate of descent and/ or power.
Since the lower front turret will probably be pushed up
in landing, clear that area of all crew members.
Ditching or Water Landing
Detailed ditching information including crew positions
have been published by AAF organizations. No attempt will
be made here to cover the detailed instructions, but merely
to discuss the airplane's characteristics and the proper tech-
nique.
The primary object in ditching is to lower the airplane
into the water with as low a downward and forward speed as
possible. Secondarily, the attitude of impact must be one
which will produce a planing instead of a diving or gouging
action following the first contact with the water.
No ditching _
tests are available at this time for complete
verificaion, but apparently both of these requirements are
met by making a landing very similar to the slow or short-
field belly landing on a runway, with the gear retracted and
the airplane trimmed. The sketch on page 43 shows ap-
proximately the best attitude for the water landing.
Page 42
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The stalling speed with power on is approximately 8 to
10 MPH, I.A.S. less than with no power. If any of the engines
are feathered, most of this reduction will be lost. If any pro-
pellers are windmilling, the landing speed should be some-
what higher than the power-off stall speed. If the landing is
being made due to fuel shortage, it might be well to land with
a few minutes fuel supply remaining for each engine to avoid
a power-off landing.
The stall speed difference between flaps up and full flaps
down is over twenty miles an hour and it is not probable
that safer contact could be made at the higher speed. The
picture shows that with full flaps the maximum lift is obtain-
able with the body at approximately 8° to the water (12°
angle of attack of the wing). This allows the body to touch
first in the region of the rear turret with the propellers still
clear of the water. The flaps will touch at approximately the
same time, but they will break immediately and will have no
effect upon the airplane's actions.
After the initial contact, all the available elevator should
be used to prevent the nose from diving into the water. If
this can be done the deceleration will be smooth and gradual.
The wings should be as level as possible at the time of con-
tact and should be kept as level as possible to prevent pivot-
ing on a wingtip.
The direction of the landing will depend on the velocity
of the wind and the size and shape of waves. If the wind is
slight and the troughs are wide, the landing probably should
be made cross wind with the body just to the down-wind side
of the crest. The main consideration here is to prevent a
wingtip or nacelle from gouging a wave and thus spinning
the airplane. If the wind velocity is high the landing should
by all means be directly into the wind, regardless of the size
and shape of the waves. The wave, not the water, is moving;
therefore wave velocity is not added to the impact speed.
Landing directly into the wind subtracts the wind velocity
Page 44
RESTRICTED
from the impact speed, whereas a cross wind landing adds
a component of the wind to the impact velocity. No exact
figure has been determined, but indications are that some-
thing over a 15 MPH wind should be the maximum for a cross
wind landing.
The use of power on all engines provides a means of
selecting a time and place for the landing. If the power
approach is made so that the final flare brings the airplane
just a few feet above the water at approximately the speed of
the power-off stall (or even slightly less), cutting the master
switch will allow the airplane to drop into the water almost
immediately. No particular danger is involved, (providing
the landing is under control), in actually powering onto the
water as in a ground landing. Propeller clearance (as shown
by the sketch) is adequate even at contact, and still longer
neglect to cut power would merely bend blades. As in the
ground belly landing, it must be remembered that since the
landing gear has as much drag as the entire airplane in flying
condition, excess speed will be dissipated very slowly during
the flare, and unless this is fully taken into account, the air-
plane may float another mile further than the point the pilot
intended conacting the water in using the wheels down
technique.
If any or all engines are dead, the approach will be
accordingly steeper to provide speed for control. This speed,
however, should be dissipated in the flare before contact.
Full consideration should be given to the fact that if no
severe damage is incurred on landing, the pressure sealed
cabins of the B-29 may keep it afloat almost indefinitely.
Salvage of the airplane then becomes an important possi-
bility. The lower hatches and seals should then be given
attention. Even the empty fuel tanks (including the bomb bay
tanks) will keep the airplane afloat with some margin. How-
ever, until the airplane's characteristics are better known,
Page 45

RESTRICTED
entering the life rafts to watch the airplane's actions from a
safe distance is strongly recommended.
WHAT TO DO WITH THE POWERPLANT
The chart in Figure 15, page 47, shows the conditions
under which the powerplants operate.
The shaded part is the region for all normal operations.
These combinations of manifold pressures and engine RPM's
give the maximum available engine and propeller efficiencies
and also prevent excessive strains on the engine, for all pow-
ers from takeoff to very low cruising power. It is seen that
two inches of manifold pressure above and below the mean
is considered allowable at cruising powers. The following
recommended settings which are given in T.O. No. 0l-20EJ-l,
lie in the center of this operating region.
RPM M.P. GPH (approx. per engine)
1300-2000 28 62-95 l Use auto lean
2100 31 110 J at these powers
2200 35 160 l
2300 39 200 l Use auto rich
2400 43.5 250 ( at these powers
2600 47.5 290 J
The fuel flow in gallons per hour (GPH) for each engine
is indicated at each setting.
Power increase is always obtained by increase in RPM
followed by opening the throttle. When full throttle is
reached, further increases in power are obtained with the
turbo boost. The numbers on the boost control are for refer-
ence only. Control is not arranged to give the same manifold
pressure at any one number at all altitudes. No harm can
come from using full available boost as long as manifold
pressure settings for each RPM are not exceeded. The aver-
age effective pressures within the cylinders remain about the
same at all powers below 31 inches and 2100 RPM and thus
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there is no bad effect upon the engine when RPM is reduced
as low as 1400 at the same manifold pressure of 28 inches
plus or minus 2 inches. In fact, this must be done to prevent
burning excessive fuel per horsepower.
In the region to the left of the operating region which is
described as the "Region of Excessive Fuel Consumption",
the manifold pressure is too low for the given RPM. The
powerplant efficiency decreases in this region as it is oper-
ated farther from the recommended settings. The lower the
manifold pressure or the higher the RPM for a given power,
the greater will be the quantity of fuel used to produce a
given power. This region is not critical in that there is no
danger of damaging the engine unless engine speeds in
excess of the highest on the chart (2600 RPM) are used. The
approach to landing is usually made in this region.
·In the region to the right of the "Desirable Region" de-
scribed as the "Region of Excessive Engine Pressures", the
manifold pressure is too high for a given engine RPM. Engine
damage as well as severe loss of efficiency is the danger of
this region, and detonation (possibly with pre-ignition) is
usually the direct cause of this damage.
With the turbosupercharger boost controls installed on
the B-29 a governor automatically limits the turbo speed to
26,400 RPM. There is no region of turbo overspeed for any
altitude. The turbo continues to turn faster at higher altitudes
at any given power, and at 30,000 feet the turbo speed at mil-
iary power is 26,400 RPM. If altitude is increased above
30,000 feet the boost control will prevent the turbo from turn-
ing any faster by automatically reducing manifold pressure
approximately I½ inches per thousand feet.
There is no need for the pilot to decrease manifold pres-
sure at altitude to prevent turbo overspeed if the boost con-
trol is working properly. However, it is well to know what
the control is supposed to do. If military power manifold
pressure (47.5 inches) is indicated above 30,000 feet, (rated
Page 48
RESTRICTED
power 43.5 inches M.P. at 34,000 feet) the control is not work-
ing properly. Since the consequences of serious turbo over-
speed might be explosion of the turbos, perhaps damaging
the front wing spar or puncturing a fuel tank, the crew should
recognize faulty boost operations and correct it by reduction
of manifold pressure with the throttles. Trying to use the
calibrating screw for reduction of manifold pressure will
likely be entirely ineffective. Probably no malfunctions
would originally occur if the individual boost system would
respond to the calibrating screw.
Malfunctioning of any boost control will most likely be
noticed in the climb when that engine holds its manifold pres-
sure as the others start dropping off at about 34,000 feet (at
rated power).
Turbo life is being sacrificed by setting the turbo
governors to the maximum allowable speed of 26,400 RPM.
It is suggested that for conservative operation and longer
turbo life, a manifold pressure reduction of 1½ inches per
thousand feet be begun for rated power at 32,000 instead of
34,000 feet. This would limit the turbo speed to approxi-
mately 24,000 RPM.
Nearly all types of flying will require some attention to
proper engine cooling. Cowl flap openings already have been
mentioned, and the following cylinder head temperatures
are allowable at various power settings:
RPM
1400-2000
2100
2200
2300
2400
2600
M.P.
28"
31
35
39
43.5
47.5
Max. Allowable
Cyl. Head Temp.
232°c.
232
232
232
248 Maximum Continuous
260 5 Min. Max. and takeoff
In hot weather be sure to let the engines cool off after
Page 49

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reaching the end of the runway before takeoff. This will
help keep the engines cool during takeoff.
The B-29 induction system including the carburetor may
be easily and completely protected from ice in all weather.
There is no source of heat for carburetor air other than
the turbosupercharger. When there is danger of icing, use
more boost. This should be done by throttling back 3 to 5
inches manifold pressure and then moving the boost control
until the desired power setting is reached. Closing the inter-
cooler (hot position) merely prevents air from flowing over
the tubes in the intercooler radiator, and this allows hot air
to go to the engine without cooling.
The necessary steps to prevent carburetor icing are:
(I) Increase to rated power if possible (part throttle)
(2) Close intercoolers
(3) Use additional boost
(4) Climb out of icing conditions
SOMETHING ABOUT THE ELECTRICAL SYSTEM
The six 28.5 volt generators on the B-29 furnish 300 am-
peres apiece for a total of 1800 amperes if all generators are
working and if the engines are turning 1600 RPM or faster.
Engines must be turning at least 1200 RPM or the generators
won't furnish any current. The auxiliary powerplant fur-
nishes an additional 200 amperes but it won't run above
10,000 feet. The 34 ampere-hour battery isn't suposed to
furnish anything continuously. For a minute or less this
supply, including the auxiliary, can be ov~rloaded to nearly
150% for a total of nearly 3000 amperes.
The first B-29s had P-2 generators which furnished only
200 amperes apiece. Some of them may still have the old gen-
erators and the total current supply will be lower.
All engine-driven generators must always be turned on
from takeoff to landing unless malfunctioning of a unit occurs.
The defective generator should be switched off.
Page 50
RESTRICTED
The auxiliary power plant and battery furnish an addi-
tional source of power for ground operation and emergencies.
The auxiliary should not be considered as a source of power
during flight. It should be used for ground operations and
during takeoffs and landings.
Normally there is no need to operate the flaps and gear
separately since the combined current is well within the
output of the generators. If the flap and landing gear motors
were started simultaneously, the starting curent peaks would
overload the system; however, snapping the switches a frac-
tion of a second apart sufficiently separates these peak loads.
Sudden reversal in the direction of either the flap or
landing gear causes peak· loads of several thousand amps
more than the capacity of the system. A pause of aproxi-
mately 10 seconds to let the motor slow down helps avoid
this overload.
In the event that one or more of the engine-driven gener-
ators are inoperative, the load on the system should be re-
duced, if possible, to values within the capacity of the system,
before attempting to operate the landing gear and flaps in
takeoff or go-around. The following table shows the minimum
system capacity that should be available before attempting
the indicated operations.
NOTE: This table is based on the assumption that other loads in the system
will be essential flight loads only
OPERATION MINIMUM POWER SUPPLY
Retracting Wing Flaps
Extending Wing Flap
Retracting Landing Gear
Extending Landing Gear
Emergency Landing
Extending Landing Gear
Normal Landing (Extending
Landing Gear and Flap)
Go-Around (Retracting Landing
Gear and Flap Together)
*A.P.P. and Battery or 1 Generator and
Battery
A.P.P., 1 Generator, and Battery; or
2 Generators and Battery
A.P.P., 2 Generators, and Battery; or
3 Generators and Battery.
A.P.P., 1 Generator, and Battery; or
2 Generators and Battery.
A.P.P. and Battery; or 1 Generator
and Battery; or 2 Generators.
A.P.P., 2 Generators, and Battery; or
3 Generators and Battery.
* Auxiliary Powerplant.
Figure 16 Page 51

RESTRICTED
The B-29 has two sets of retraction motors for the nose
gear and main landing gear: the normal and emergency
motors.
The wing flap and bomb bay doors may be operated by
using their normal motors or a portable motor usually located
to the left of the tunnel, above the rear spar on the inner
wing.
The emergency landing gear motors and the portable
motor outlets, 3 of which are located in the bomb bays, are
connected to a separate system and may be used independent
of the normal system.
The emergency system may be run by the engine gen-
erators when the landing gear transfer switch, located on the
pilot's control stand, is in the "Emergency" position. This
system may be run by the auxiliary power plant alone and
the battery or the battery alone when the landing gear trans-
fer switch is in the "Normal" position and the bus selector
switch, located in the battery solenoid shield, is in the "Emer-
gency'' position.
The nose gear and main landing gear operate one at a
time instead of all together when they are powered by the
"Emergency" motors, and then allow from 2 to 3 minutes for
them to go up or down.
When the landing gear is to be lowered by the emer-
gency system the landing gear nacelle doors must first be
opened by pulling the emergency release handle located
adjacent to the emergency landing gear switch. The landing
gear nacelle doors can be closed only by their individual
normal motors.
The order of operation by the "Down" or "Up" position of
the emergency landing switch, located in the pilot's control
stand is: (1) Nose Gear, (2) L.H. Main Gear, and (3) R.H. Main
Gear.
The tail skid can be operated only by the normal system
as it is not considered essential to emergency landing.
Page 52
RESTRICTED
The normal system may be energized by the auxiliary
powerplant and/ or battery when the bus selector switch is
in its "Normal" position.
SOMETHING ABOUT CABIN PRESSURE AND HEAT
The diagram in Figure 17, page 54, shows the way air
is supplied to pressureize the cabin. Cabin air is taken from
the duct leading from the engine turbosupercharger to the
carburetor. The amount of air going to the cabin is very small
in comparison to the air going to the engine. To prevent
very large losses of supercharger air into the cabin duct
(which would leave the engine unsupercharged) in case of
the duct being shot away, a restriction is located in the duct
near the nacelle. The air then goes through the aftercooler
which acts as a radiator, cooling the cabin air if it has been
heated by turbo supercharging. If no turbo is being used the
air may be cold, and hot air from the exhaust shroud is passed
through the aftercooler instead of the alternate cold air from
the leading edge. The air then passes through the cabin air
valve into the distribution ducts in the tunnel. A safety fire
valve at the nacelle automatically closes if the cabin air tem-
perature raises sufficiently to melt its lead alloy fuse.
To get any air flow into the cabin, the pressure of the
turbo air must be greater than that in the cabin. This requires
a certain minimum turbo speed which means a minimum
engine power on the inboard engines. To keep the drain on
the turbo small, the cabin airflow should be kept low.
When cruising at low weights, the power of the engines
may not be sufficient to keep up the cabin pressure even at
low flow. The RPM of the inboard engines may be increased
about 200 RPM above that of the outboard engines to furnish
enough boost for cabin pressure. For best range do not syn-
chronize inboard and outboard engines. The cruising air-
speed should be kept at the recommended for long range;
if this is done there will be no loss in range, provided not
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more than 2100 RPM and 31 inches in auto lean is used on
the inboard engines.
The following is a check list for getting heat and pressure
in the cabin when it is needed:
To Operate Without Cabin Pressure
(A) Ground running, Takeoff and Descent
(1) Open at least one pressure door
(2) Turn cabin flow control off
(3) Turn cabin temperature control on automatic
(B) Flying in Hot Weather
(I) Open all pressure doors
(2) Turn cabin flow control off ·
(3) Turn cabin temperature control on automatic
(C) Flying in Cold Weather
(1) Open only rear door in rear compartment, close all
others
(2) Turn cabin air valves on
(3) Turn cabin flow control on
(4) Turn cabin temperature control on
(5) Set the minimum flow control low unless there is
insufficient heat and air for defrosting
To Operate With Cabin Pressure
(A) General Procedure
(1) Close all pressure doors
(2) Turn cabin air valves on
(3) Turn cabin temperature control on automatic
(4) Close pressure relief valve
(5) Unlock cabin pressure regulators
(6) Turn cabin flow control on
(7) Retard throttles on No. 2 and No. 3 engines to hold
desired manifold pressure
(8) When changing from unsupercharged to super-
charged cabin above 8,000 feet altitude, the rapid
change in cabin pressure may be uncomfortable. Re-
Page 55

RESTRICTED
tard throttles on No. 2 and No. 3 engines until descent
on cabin climb meter is less than 2000 feet per minute
(B) Flying at Medium and High Power
(1) Turn cabin flow control on
(2) Set manifold pressure and RPM according to cruising
charts
(C) Flying at Low Power for Range or Endurance
(1) Turn cabin flow control on low
(2) Set manifold pressure and RPM to maintain cruising
or hovering airspeed. If power is too low to give suf-
ficient airflow on gages, there is insufficient power on
the inboard engines and the warning light will go on.
Then:
(a) Increase RPM of inboard engines to give low flow
(b) Set outboard engines at RPM to maintain proper
airspeed
(c) Transfer fuel to correct for unequal power
NOTE: When the above steps are followed, the max-
imum range will not be affected, providing power
does not go above 2100 RPM, 31 inches M.P. Syn-
chronization of propellers will decrease range.
(D) Flying at Maximum Altitude- Above 33,000 Feet
(1) Turn cabin flow control to low
(2) Close cabin air valve to give low flow on gages
(E) Descending
(1) Keep enough power on either inboard engine to give
low flow on cabin flow gage.
Testing Cabin for Leakage
(1) Fly the airplane above 20,000 feet
(2) Turn cabin flow control to No. 2 engine off and to No.
3 engine on
(3) Turn minimum flow control to low flow
(4) Turn cabin air valve to No. 2 engine off, and set that
to No. 3 engine to obtain "low flow" on the airflow
gage.
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RESTRICTED
(5) The cabin rate of climb should stay at 0, and the
cabin altimeter should remain steady after stabilizing.
(6) If cabin leakage is too great to keep cabin pressure,
open the cabin air valve on No. 3 engine and set the
minimum flow control to get sufficient flow to main-
tain a steady cabin pressure
(7) Check for leaks-see the diagram in the cabin
WHERE TO GET MORE INFORMATION
At the present time, all of the flight testing is not com-
pleted. Most of the B-29s that are flying now are going to do
important work aside from routine flight testing. Therefore,
there still are some items of information which are, at best,
only estimates. In general, the information in this book super-
sedes all previously issued information where there is dis-
agreement. As later information becomes available probably
some of the items discussed here will be further modified.
The book is considered to be supplementary to B-29
Technical Orders and the Operations Manual. These should
be consulted for more detailed informati;n, Service represen-
tatives will always be on hand to assist the pilots in securing
more information.
If this book helps the B-29 pilot to be confident that he
can fly the airplane in any condition, it will have served its
purpose. No matter how well any airplane is designed and
built, it will be only as good as the man who flies it.
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