Advertisement
11
SECTION
T h e F I p e r
C a m u n c h e
. -
ing airspeed
Mow
95
MPH
at
low
alti~udes has
the
added disad-
vantage
of cuuing down forward visilility,
so
no speeds below
that
figure are
recommended.
The
gross
weight
stalling speed of
the
two
Comanche
models
with
full
flaps is 61 and
64 MPH
respecliveIy.
The
stall speed
increas-
es
about
5
MPH
with flaps up. All
controls
are effective
at
speeds
down
to
ihe
slatling speed,
and
stalls
are gentle and
easily controlled.
V.
Cruising:
The
cruising speed
of
the Comanche
models
is
determined
by
many iactors
including power setting, altitude,
temperature,
load, and
-
equipment
installed on the
airplane.
For
h e
180
Comanche,
d ~ e
normal recommended
cruising
speed is
160 MPH
at
75% power
at
8000 feet
al~itude. This
power
setting is obtailied under standard conditions
at
2400
RPM
and a t m t
22''
M. P.
Fuel
consumption
at
this speed approximates 10 gallons
*
per
hour.
This
gives a cruising
range
with standard fuel of
5 hours
or 800
miles,
and with reserve fuel 6 hours
or 960
miles.
The 250
Comanche bas
a
maximum recommeded
cruising speed
of
181 MPH
at
75%
power
at 7000 ieet,
24.00
RPM
and
22.6N
M .
P.
With
a
iuel
consumption
of 14
gallons per hour, this cruising bon-
dirion gives
a
range of
4.3
bours or
785
miles.
T o
keep engine
wear,
fuel
consumption, and noise at reasonable
levels, cruising
RPMb
horn 2100
to
24.00 are recommended,
wjkh
apprupriale Manifold Pressures
to
attain
power settings
of 65%
to
75%
pawcr
at low
and intermediate altitudes.
With
the Harkell propeller installation
on h e
180 HP
engine,
Manihld
Pressures
o f
more ihan
23.5" should
not be used
a L
less
than 2250
RPM
l o
avoid undesirable
propeller
stresses. Qihcrwise,
there arc no pnwer setting limitations on
this installation. Jn !be
case
of the
McCauhy propeller, cruising at 2450
RPM
or
higher
with Manifold
Pressures over 24.5'' must
be
avoided.
T h i s
indbces
no
operhional handicap because
thcse
power seuings are too
high
(over
8 0 ! %
puwer)
to
be
practical.
With
this installalion, Mani-
fold
Pressures over 25''
should not be
used at
less
than
2100
RPM.
Far minimum
iuel
consumption
and
maximum eiticicncy, the
best power ser~ings during
cruising Aight are with minimum RPM
and
the
necessary Mnnifold Pressures
to
obtain
a
given percent of
power,
consislent
with the
above
limita~ions.
Engine smoatlinesa
and
noise level
should
be
major
factors
in
delermining the best
RPM.
Advertisement
