Piper Twin Comanche B User guide

PIPER
TWIN
COMANCHE
B
OWNER’'S
HANDBOOK

Piper Aircraft Corporation, Lock Haven, Pa.
U.S. A.

NOTICE
THIS
HANDBOOK
IS
NOT
DESIGNED,
NOR
CAN
ANY
HANDBOOK
SERVE,
AS
A
SUBSTITUTE
FOR
ADEQUATE
AND
COMPETENT
FLIGHT
INSTRUCTION,
OR
KNOWLEDGE
OF
THE
CURRENT
AIRWORTHINESS
DIRECTIVES,
THE
APPLICABLE
FEDERAL
AIR
REGULATIONS,
AND
ADVISORY
CIRCULARS.
IT
IS
NOT
INTENDED
TOo
BE
A
GUIDE
OF
BASIC
FLIGHT
INSTRUCTION,
NOR
A
TRAINING
MANUAL.
THE
HANDBOOK
IS
DESIGNED:
1.
TO
HELP
YOU
OPERATE
YOUR
TWIN
COMANCHE
WITH
SAFETY
AND
CONFIDENCE.
TO
MORE
FULLY
ACQUAINT
YOU
WITH
THE
BASIC
PERFORMANCE
AND
HANDLING
CHARACTERISTICS
OF
THE
AIRPLANE.
3.
TO
MORE
FULLY
EXPLAIN
YOUR
TWIN
COMANCHE'’S
OPERATION
THAN
IS
PERMISSIBLE
TO
SET
FORTH
IN
THE
AIRPLANE
FLIGHT
MANUAL.
IF
THERE
IS
ANY
INCONSISTENCY
BETWEEN
THIS
HANDBOOK
AND
THE
AIRPLANE
FLIGHT
MANUAL
APPROVED
BY
THE
F.A.A,
THE
AIRPLANE
FLIGHT
MANUAL
SHALL
GOVERN.
Revised
text
and
illustrations
shall
be
indicated
by
a
black
vertical
line
in
the
margin
opposite
the
change.
Additional
copies
of
this
manual,
Part
No.
753
697,
may
be
obtained
from
your
Piper
Dealer.
Published by
PUBLICATIONS
DEPARTMENT
Piper
Aircraft
Corporation
753 697
Issued: August1965
Revised:
October
1973

SECTION |
SPECIFICATIONS
Performance .
Weights
Power Plant .
Fuel and Oil .
Baggage Area
Dimensions
Landing Gear.

TWIN COMANCHE ‘‘B” SECTION I
SECTION |
SPECIFICATIONS
PERFORMANCE
Performance figures are for airplanes equipped for cross-
country transportation and flown at gross weight under standard
conditions at sea level or stated altitude. Any changes in equip-
ment may result in changes in performance.
Take-off Run (short field, ft) 1250
Take-off Distance Over 50-ft Barrier (ft) 2160
Vmc
(mph)
(as
determined
by
the
F.A.A.)
90
Stalling Speed (gear and flaps down, power off, mph) 69
Stalling Speed (gear and flaps up, power off, mph) 76
Best Rate of Climb (ft per min) 1460
Best Rate of Climb Speed (mph) 112
Best Angle of Climb Speed (mph) 90
Single Engine Rate of Climb (ft per min) 260
Best Single Engine Rate of Climb Speed (mph) 105
Absolute Ceiling (ft) 20,000
Service Ceiling (ft) 18,600
Single Engine Absolute Ceiling (ft) 7,100
Single Engine Service Ceiling (ft) 5,800
Altitude Cruising Speeds (mph)
Top Speed (mph) 205
Cruising
Speed
(75%
power
at
sea
level)
(mph)
181
Cruising
Speed
(75%
power
at
8,000)
(mph)
194
Optimum
Cruising
Speed
(65%
power
at
12,000)
186
(mph)
700313
1

SECTION
|
TWIN
COMANCHE
“‘p’
SPECIFICATIONS (cont):
PERFORMANCE
Fuel
Consumption
(75%
power)
(gph)
(both
engines)
17.2
Fuel
Consumption
(65%
power)
(gph)
(both
engines)
,
15.2
Cruising
Range
(75%
power
at
8,000
ft)
(mi)
048
*
Cruising
Range
(65%
power
at
12,000
ft)
(mi)
1025
*
Cruising
Range
(45%
power
at
16,000
ft)
(mi)
1116
*
*
84
gal.
usable
fuel
Landing
Roll
(short
field,
flaps
down,
ft)
700
Landing
Over
50-ft
Barrier
(flaps
down,
ft)
2100
WEIGHTS
Gross
Weight
(lbs)
,
3600
Empty
Weight
(Standard)
(Ibs)
2207
*
USEFUL
LOAD
(Standard)
(1bs)
1393
*
*
These
weights
are
approximate.
710310

TWIN
COMANCHE
‘‘B”’
SECTION
I
SPECIFICATIONS (cont):
POWER PLANT
Engine - Lycoming 10-320-B
Rated Horsepower 160
Rated Speed (rpm) 2700
Bore (in.) 5.125
Stroke (in.) 3.875
Displacement (cubic in.) 319.8
Compression Ratio 8.5:1
Dry Weight (Ibs) 295
FUEL AND OIL
Fuel Capacity (U.S. gal) , 90
Unusable fuel (inboard tanks only) 6
Fuel, Aviation Grade (minimum octane) 91/96
0il Capacity (qts) (each engine) 8
BAGGAGE AREA
Maximum
Baggage
(lbs)
250
Baggage
Space
(cubic
ft)
20
Baggage
Door
Size
(in.)
19
x
21
700313 3

e
SECTION
|
TWIN
COMANCHE
“‘B’"
SPECIFICATIONS
(cont):
DIMENSIONS
Wing
Span
(ft)
36
Wing
Area
(sq
ft)
178
Length
(ft)
25,2
Height
(ft)
8.2
Wing
Loading
(lbs
per
sq
ft)
20.2
Power
Loading
(Ibs
per
hp)
11.3
Propeller
Diameter
(in.)
72
LANDING GEAR
Wheel
Base
(ft)
7.3
Wheel
Tread
(ft)
9.8
Tire
Pressure
(psi)
Nose
42
Main
42
Tire
Size
Nose
(six-ply
rating)
6.00
x 6
Main
(six-ply
tating)
6.00x
6
4
700313
e

SECTION |
TWIN
COMANCHE
“‘B”’
700313

SECTION 11
DESIGN
INFORMATION
Engine and Propeller
Fuel Injection
Structures .
Landing Gear.
Control System
Fuel System .
Electrical System
Vacuum System .
Instrument Panel
Instrument Static Pfessure System .
Heating and Ventilating System .
Seats
Finish |
Baggage Area
Stall Warning System
10
11
14
16
17
20
21
22
23
23
24

TWIN
COMANCHE
*‘B”
SECTION
1
SECTION i
DESIGN INFORMATION
ENGINE
AND
PROPELLER
The
Lycoming
10-320-B
four
cylinder,
fuel
injected
engines
are
rated
at
160
horsepower
at
2700
rpm.
These
engines
are
equipped
with
geared
starters,
fuel
injectors
and
shielded
ignition
systems.
Engine
mounts
are
of
steel
tube
dynafocal
mount
construction.
Engine
cowls
are
cantilever
structures
attached
at
the
firewall,
with
side
panels
which
are
quickly
removed
by
means
of
quick
release
fasteners.
The
exhaust
system
is
a
cross-over
type
with
exhaust
gases
directed
overboard
at
the
bottom
of
the
nacelles
in
the
area
of
the
cowl
flaps.
The
cowl
flaps
are
located
on
the
bottom
of
the
engine
nacelles
and
are
manually
operated
by
push-pull
controls
located
in
the
cabin
to
the
right
of
the
power
control
quadrant.
Oil
coolers
are
mounted
on
the
left
rear
baffle
of
each
engine.
Air
passes
through
the
oil
coolers
before
reaching
the
area
of
the
cowl
flaps.
The
propellers
are
Hartzell
HC-E2YL-2
constant-speed,
controllable,
full-feathering
units.
These
are
controlled
entirely
by
use
of
the
propeller
control
levers
located
in
the
center
of
the
power
control
quadrant.
Feathering
of
the
propellers
is
accom-
plished
by
moving
the
controls
fully
aft
through
the
low
RPM
detent
into
the
feathering
position.
Feathering
takes
place
in
approximately
three
seconds.
A
propeller
is
unfeathered
by
moving
the
prop
control
ahead
and
engaging
the
starter.
(See
Section
III
for
complete
feathering
and
unfeathering
instructions.)
700313
6

SECTION I TWIN COMANCHE “‘B”
FUEL INJECTION
The Bendix RSA-5 fuel injection system is based on the
principle of measuring engine air consumption by use of a venturi
tube and using airflow to control fuel flow to the engines. Fuel
distribution to the cylinders is accomplished by a fuel flow
divider.
Fuel pressure regulation by means of the servo valve causes
a minimal drop in fuel pressure throughout the metering system.
Metering pressure is maintained above vapor forming conditions
while fuel inlet pressure is low enough to allow the use of a
diaphragm. pump. Vapor lock and associated problems of difficult
starting are thus eliminated.
Incorporated in the servo regulator is the airflow sensing
system which contains a throttle valve and venturi. The differ-
ential pressure between the entrance and the throat of the venturi
is the measurement of air entering the engine. These pressures
are applied across an air diaphragm in the regulator. A change in
power changes the airflow to the engine and across the diaphragm
in the regulator.
Mounted on top of the engine is the ported fuel flow divider
with four nozzle lines routed to the cylinders. The divider con-
tains a spring loaded positive shut-off valve. Within each cylinder
are continuous flow air bleed nozzles with provisions to eliminate
the adverse effects of low manifold pressure when idling. Since
fuel metering is provided by the servo regulator rather than the
nozzles, more uniform cylinder head temperatures result and a
longer engine life is possible.
Induction air for the engine enters the opening in the nose
cowl and is picked up by a large air duct at the right rear baffle.
The air is directed through a filter and on to the servo regulator.
An alternate air source for the induction system contains a spring
loaded door at the throat of the servo regulator. This door op-
erates automatically if primary source is obstructed or manually
by the push-pull control on the right side of the power control
quadrant. The primary system should always be used for take-off.
7
700313
R

TWIN
COMANCHE
“‘B”
SECTION
Il
STRUCTURES
Structures are of sheet aluminum construction and are de-
signed to ultimate load factors well in excess of normal require-
ments. All components are completely zinc chromate primed and
exterior surfaces are coated with acrylic lacquer.
The main spars of the wings are joined with high strength
butt fittings in the center of the fuselage, making in effect a
continuous main spar. The spars are attached to the fuselage at
the side of the fuselage and in the center of the structure; wings
are also attached at the rear spar and at an auxiliary front spar.
The wing airfoil section is a laminar flow type, NACA-
642A215, with maximum thickness about 40% aft of the leading
edge. This permits the main spar, located at the point of max-
imum thickness, to pass through the cabin under the rear seat,
providing unobstructed cabin floor space ahead of the seat.
LANDING GEAR
The nose gear is steerable with the rudder pedals through a
40 degree arc. During retraction of the gear, the steering mecha-
nism is disconnected automatically to reduce rudder pedal loads
in flight. The nose gear is equipped with a hydraulic shimmy
dampener.
Retraction of the landing gear is accomplished through the
use of an electric motor and gear train, actuating push-pull cables
to each of the main gear and a tube to the nose gear. The landing
gear motor is beneath the center floor panel and the selector
switch on the instrument panel to the left of the power control
quadrant.
To guard against inadvertent movement of the landing gear
selector on the ground, the handle must also be pulled aft before
moving
it
upward.
The
gear
selector
has
the
shape
of
a
wheel
to
700313 8

SECTION
I
TWIN
COMANCHE
‘B’
distinguish
it
from
the
electric
flap
control
which
has
an
air-
foil
shape.
As
an
added
safety
@ / feature, the warning horn is
connected
to
the
gear
selector
%
WMAX.
GEAR
(\
;
OOWN
SPEED
i
switch.
The
horn
will
then
op-
i
150
Mo
erate
if
the
selector
is
moved
|
i
i
AR
Doww
to
the
UP
position
with
the
4
ATETET
master switch on and the
weight of the airplane on the
landing gear. To prevent gear
retraction on the ground, an
anti-retraction switch is in-
Gear
Selector
Switch
stalled
on
the
left
main
gear.
This
prevents
the
completion
of
the
electric
circuit
to
the
landing
gear
motor
untilthe
gear
strut
is
within3/4
inch
of
full
extension.
The
gear
indicating
lights
are
located
conveniently
above
and
below
the
gear
selector
switch.
The
green
indicating
light
(located
below the selector switch) shows that all gears are down and locked.
The amber light (located above the gear selector switch) is the gear up
indication. The amber light will flash when power is reduced on one
engine and the gear is up. The warning horn will operate when power is
reduced (below approximately 12" of manifold pressure) on both
engines and the gear is not down and locked. The pilot should become
familiar with the gear warning horn to distinguish it from the stall
warning horn. GEAR INDICATION LIGHTS ARE AUTOMATICALLY
DIMMED WHEN THE INSTRUMENT LIGHTS ARE TURNED ON,.
The brakes are actuated by toe brake pedals mounted on the left
set of the rudder pedals. Hydraulic brake cylinders above the brake
pedals are accessible in the cockpit for servicing. Parking brake valves
are incorporated in each cylinder and have two cables attached from -
the parking brake “T” handle. To prevent inadvertent application of
the parking brake in flight, a safety lock is incorporated in the valves,
thus eliminating the possibility of pulling out the “T’” handle until
pressure is applied by use of the toe brakes. Toe brakes for the right
side are available as optional equipment.
710310

TWIN COMANCHE “‘B”
SECTION II
A tow baris provided with
each aircraft. When not in use
it is stowed next to the main
spar. It may be removed by
lifting the flap covering the
forward side of the spar and
removing the bar from its
fasteners.
When towing with power
equipment, caution should be
used not to turn the nose
gear beyond its 40 degree arc
as this may cause damage to
the nose gear and steering
mechanism.
CONTROL SYSTEM
Dual
flight
controls
are
Cables
connect
the
movable
pedals
and
control
columns.
Directional
and
longitudi-
nal
trim
is
provided
by
an
adjustable
trim
mechanism
for
the
rudder
and
stabilator.
The
manual
rudder
trim
control
is
located
to
the
right
of
the
throttle
quadrant.
Max-Lift
electrically
op-
erated
flaps
are
used
on
the
Twin
Comanche.
The
flaps
are
operated
by
an
electric
motor;
they
can
be
lowered
700313
Tow Bar Stowage
provided as standard equipment.
control surfaces with the rudder
e
Rudder Trim and Flap Controls
10

SECTION
I
TWIN
COMANCHE
““‘B”
and
stopped
in
any
desired
position.
The
airfoil
shaped
flap
con-
trol
is
to
the
right
of
the
power
control
quadrant.
Located
on
the
instrument
panel
is
a
flap
position
indicator
marked
to
show
the
position
of
the
flap
relative
to
the
wing.
A
range
for
take-off
operation
is
also
shown.
Located
in
the
inboard
end
of
the
right
flap
is
a
lock
which
holds
the
flap
in
the
UP
position
so
that
it
can
be
used
as
a
step
for
entry
or
exit.
A
second
lock
is
incorporated
to
prevent
the
flap
from
going
full
down
in
case
a
step
load
is
applied
and
the
up
lock
is
not
fully
engaged.
FUEL SYSTEM
The
fuel
is
carried
in
four
integral
fuel
cells
located
in
the
leading
edge
sections
of
the
wings.
Capacity
of
the
two
main
fuel
cells
is
30
gallons
each,
of
which
27
gallons
is
usable.
The
auxiliary
fuel
system
consists
of
two
15
gallon
cells
(all
usable)
installed
in
the
wings
just
outboard
of
the
main
fuel
cells.
Wing
tip
tanks
are
available
as
optional
equipment.
Auxil-
iary
fuel
and
tip
tank
fuel
is
to
be
used
in
level
flight
only.
The
cells
should
be
kept
full
of
fuel
during
storage
of
the
airplane
to
prevent
accumulation
of
moisture
and
deterioration
of
the
cells.
For
storage
of
more
than
ten
days
without
fuel,the
cells
should
be
coated
with
light
engine
oil
to
prevent
excessive
drying.
During
normal
operation
use
the
engine
driven
fuel
pump
to
draw
fuel
from
the
cell
directly
adjacent
to
that
engine.
How-
ever,
fuel
can
be
drawn
from
any
cell
to
both
engines
through
use
of
the
engine
driven
fuel
pump
or
the
electric
auxiliary
fuel
pump.
For
emergency
single
engine
operation
a
crossfeed
is
pro-
vided
to
increase
the
range.
When
using
fuel
from
tanks
on
the
same
side
as
the
operating
engine,
the
position
of
the
fuel
se-
lector
will
remain
the
same
as
for
normal
operation
with
the
11
700313

SECTION I
TWIN COMANCHE “B”’
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700313

SECTION
II
TWIN
COMANCHE
“‘B"
auxiliary
fuel
pump
off
unless
the
engine
driven
pump
is
inoper-
ative.
NOTE
Do
not
put
both
fuel
selectors
in
the
crossfeed
position
at
the
same
time.
When
using
fuel
from
cells
on
the
opposite
side
of
the
oper-
ating
engine,
move
the
fuel
selector
for
the
inoperative
engine
to
the
main
or
auxiliary
position;
then
move
the
fuel
selector
for
the
operating
engine
to
the
crossfeed
position.
For
single
engine
landing,
fuel
must
be
pumped
from
the
main
cell
on
the
same
side
as
the
operating
engine.
The
fuel
strainers
for
the
system
are
located
beneath
the
floor
panel
in
the
center
section
of
the
fuselage.
Daily
draining
of
the
strainers
may
be
accomplished
in
the
cockpit
by
opening
the
hinged
access
door
located
in
the
floor
panel
just
aft
of
the
fuel
selector
handles
and
pulling
up
on
the
knob
located
in
the
center
of
the
selector
valve.
The
general
procedure
for
draining
the
fuel
system
is
to
open
the
strainer
quick
drain
for
several
seconds
with
the
fuel
cell
selector
on
the
main
cell,
then
to
change
the
selector
to
the
auxiliary
cell
and
repeat
the
process.
Allow
enough
fuel
flow
to
clear
the
lines
as
well
as
the
strainer.
Positive
fuel
flow
shut-off
can
be
observed
through
the
clear
plastic
tube
that
carries
the
fuel
overboard.
Located
inside
the
fuel
valves
is
a
by-pass
valve
which
will
open
at
1/2
psi
differ-
ential
pressure
if
the
strainer
screen
becomes
blocked.
Fuel
quantity
is
indicated
by
two
electric
gauges
located
be-
low
the
instrument
cluster.
The
instruments
are
connected
to
a
transmitter
unit
located
in
each
fuel
cell.
The
gauges
will
indi-
cate
the
amount
of
fuel
available
in
the
cells
that
are
selected.
13
700313

TWIN
COMANCHE
‘““B”’
SECTION
Il
ELECTRICAL SYSTEM
Electrical
power
for
the
Twin
Comanche
is
supplied
by
a
12
volt,
direct
current
system.
Incorporated
in
the
system
as
standard
equipment
are
a
12
volt
50
ampere
generator
and
a
35
ampere-hour
battery,
which
furnish
electrical
power
during
op-
eration.
The
battery
is
located
in
the
fuselage
nose
section,
in
a
sealed
stainless
steel
battery
box.
Refer
to
the
Maintenance
Section
for
servicing
of
the
battery.
Dual
generators
are
avail-
able
as
optional
equipment.
Electrical
switches
for
the
various
systems
are
located
on
the
lower
left
instrument
panel.
The
circuit
breakers,
located
under
the
floorboard
aft
of
the
nose
wheel
well,
automatically
break
the
electrical
circuit
if
an
overload
occurs.
To
reset
the
circuit
breakers
simply
push
in
the
reset
button.
It
may
be
neces-
sary
to
allow
approximately
two
minutes
for
the
circuit
breakers
to
cool
before
resetting
them.
Corrective
action
should
be
taken
in
event
of
continual
circuit
breaker
popping.
It
is
possible
to
manually
trip
the
breaker
by
pulling
out
on
the
reset
button.
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