Cessna
120/140
by
Budd Davisson, courtesy of
www.airbum.com
Stacking
Cessna's Littlest Against Other Classics
In 1946, when
factories were cranking-out little airplanes
like elves making cookies, Cessna didn't
want to be left behind. They had done their
own marketing studies and they too were
convinced a world awash in ex-military
pilots and GI's waving their GI bill checks
would want airplanes. Lots of airplanes.
They couldn't know how wrong they were.
Cessna, however, didn't
have a design ready to go, where most other
manufactures had been cranking out two-place
training/recreational aircraft before the
war. Cessna had to start from scratch.
Although it isn't known how much, or if,
they studied the Luscombe, there are too
many configuration similarities to think
otherwise. It would have to be assumed, they
at least took note of that pre-war
airplane's size, construction and success
and took off from there.
120/140 Model
Differences.
Let's start the conversation about
Cessna 120/140's off right by passing along
the phone and address of the Cessna 120/140
club. They are the people with all the
answers.
Cessna 120/140 Club
Dave Lowe-President
Box 830082
Richardson, TX 75083
(502) 736-5392
The littlest Cessnas are
not easy to tell apart and, for most of us,
it was a proud day when we finally
understood the subtle differences between
the three basic models of two-place classic
Cessnas, the 120, 140 and 140A.
First of all, the 120 and
140 were initially produced concurrently.
It's unclear, however, whether the 120 was
to be an economy model of the 140 or the 140
was to be the luxury version of the 120.
However significant the marketing department
thought the differences to be in 1946, the
gap has narrowed to zero, since most
consider the airplanes to be nearly
interchangeable. The 140A, however,
signalled a relatively major design
improvement.
The 120 and 140
All
Cessna 120s and 140s originally had fabric
wings, two steel struts and completely
aluminium structure. A few have had the
fabric replaced with metal in the half
century since their birth. In fact, a few of
the airplanes were even converted to
tricycle gear. Don't ask why, we don't
understand either. Both airplanes had the 85
hp Continental, although the 140 had an
electrical system as standard equipment.
These days it's seldom a 120 is seen without
an electrical system. However, it's a fact
that a straight, clean 120 sans electrical
will out fly the rest. In little airplanes,
weight is everything.
The visual differences
between the two models include items which
only the 140 has: the rear quarter windows
and long, skinny flaps. We'll discuss the
flaps later, but they shouldn't be the
deciding factor between buying one model or
the other. Then, as if things aren't
confusing enough, a lot of 120s have
magically sprouted the quarter windows of
the 140.
140's received an
up-dated instrument panel in 1948 which
eliminated the "old-fashion" looking central
cluster of instruments. A new floating panel
spread the instruments across the cockpit.
Radios are usually mounted left of the
pilot's control yoke.
Cessna 140A
The "A" model was introduced in 1949,
presumably in an attempt to jump-start
flagging sales. An estimated 525 were built,
including a small number of "Patroller"
versions with Plexiglas doors, 42 gallon
tanks (!) and a message tube though the
floor. The fuselage remained the same, but
the wings were completely redesigned for the
140A. The blunt, rounded planform
disappeared to be replaced by an even more
"modern" appearing semi-tapered shape. When
Fowler flaps were later added, these were
the wings which would be used on the
still-to-come 150s. The C-85 was replaced
with a C-90 in the 140A.
140A wings are
stressed-skin aluminium, which eliminates
the need for the second strut. This is why
"A" models have a single, aluminum strut.
The ailerons run the entire length of the
tapered section and the tips are squared
off. The flaps were shortened, but are
several inches wider than straight 140 flaps
and seem to be a little more effective.
"A" model landing gear
legs are swept forward to place the wheels
further ahead of the CG than on the earlier
airplanes. This was done to protect the
airplane from pilots transitioning out of
other two-place airplanes who had never
flown with toe-brakes. This is why it's
common to see 120/140's with steel
extensions bolted to the gear legs which
move the wheels ahead about four inches.
Many consider this to be overkill, as the
brakes have to be hit fairly hard to make
the tail come up. It's a training problem
more than a hardware design flaw.
Mechanical Description
If you want to know how a 120/140 is
built, look at a C-150/152. Structurally,
with the exception of the welded steel
struts of the 120/140s, and the fabric
covered wings, they are almost identical.
The spring steel landing
gear of the 120/140 was the first
large-scale application of Steve Wittman's
patent and it obviously worked. There have
been a few incidents of gears cracking
through the rivet holes (many are now
bolted) which hold the steel steps in
position but a simple Zyglo test will show
if there are problems there.
Other than corrosion
problems typical of all old aluminium
airplanes (along the rear spars or anywhere
which can trap gravity-driven condensation),
the airplanes have been relatively free of
mechanical maladies. The most common
problems include cracked elevator hinges and
an occasional cracked rear fuselage
bulkhead.
The brakes are one area
of concern. The originals were Goodyears
with floating disks held in alignment with
spring clips. They used small, round brake
pucks which have gotten terribly expensive
and many owners machine down automotive
pucks to fit (ssshhhh, the feds might hear).
A much bigger worry is the possibility of a
brake locking, if a retaining clip is lost
and the disk cocks over and gets jammed.
Converting to McCauley or Cleveland brakes
is the usual fix.
Incidentally, because of
the outside storage and general age of the
airplanes, their wiring bundles are
sometimes frayed and brittle. Check all
wiring carefully.
A note about the
airplane's mechanical character: This is an
airplane that responds beautifully to TLC
and elbow grease. Everything about it is
easy to take apart for cleaning and
painting.
Flying Characteristics
Each classic airplane has its own flying
personality and so does the 120-140. It's
important to remember it's a post war
design. Most of its contemporaries were
originally designed before the war to
perform on the A-50 or A-65 so they are
smaller and lighter. The C-120/140 is a
bigger airplane and is a little heavier
feeling and flying than something like a
Luscombe or a Taylorcraft. It doesn't feel
quite as much like a maple seed in the wind,
as do some of the others. Make no mistake,
however, it is still a very light airplane.
Depending on the model, they'll weigh-in
empty at 950-1000 pounds and gross at 1,425
pounds (525 pounds useful).
The first thing you'll
notice on boarding a 120/140, is that
getting in isn't much of a hassle. Although
some purists de-cry the use of control
wheels rather than sticks, having the floor
free of obstacles does ease entry.
Once in, the next thing
you notice is that seeing over the nose is
possible with only a slight stretch. With a
cushion behind them, the average-height
pilot can see the centreline without
stretching. The cockpit is slightly narrower
than the latest C-152, but about the same as
its contemporaries. This makes it fine for
the FAA-standard 170 pound pair but gets
crowded rapidly as crew dimensions increase.
Unless converted to key start, the airplane
has a separate pull-to-start handle which,
to a pilot used to modern Spam cans, seems
unusual. Once the engine is running, the
straight exhausts are evident even at idle.
On takeoff they really bark. It's hard to
believe we all used to fly these without
headsets, as a matter of course. No wonder
we're all half-deaf.
If the tailwheel is in
even remotely good shape, the airplane will
taxi nearly as effortlessly as a nosewheel
airplane, needing an occasional tap on the
brakes to make sharp corners. The excellent
visibility makes it that much easier.
Take-off performance is
directly related to the amount of weight on
board. As with all lightly wing loaded,
low-powered airplanes, the two-place Cessnas
are different airplanes solo or dual. In no
case, however do they float off the ground
like a Cub or Luscombe. Actually, they
takeoff remarkably like a Cessna 152,
although without as much ground roll.
When the tail is raised
during takeoff, the spring gear is
immediately noticeable because it doesn't
have the solid feel of a bungee gear and
"wallows" just a little. Here, it feels
almost exactly like a Citabria and for the
same reason. If the wind is on the nose, the
airplane will track almost perfectly
straight. It will, however, try to gently
turn into a crosswind. A little rudder
pressure takes care of that.
If the crosswind is a
real howler, the pilot will have to work to
keep the wing down because the ailerons
don't get effective until there is a fair
amount of wind going across them. Somewhere
around 25-30 mph, they start coming alive.
The handbooks
say a Cessna 140 will climb at 700 fpm at
sea level and gross weight. There are
probably some that will do that, but most
are closer to 500-600 fpm in that situation.
As density altitude increases expect climb
to go down accordingly. Most pilots use fuel
load as the variable factor. With 22 gallons
usable and a fuel burn of only 5 gallons per
hour, leaving 60 pounds of fuel on the
ground, still gives a two-plus hour
endurance and affects climb performance
noticeably. Here again, overall performance
is in the ball park with the C-152.
The climb and cruise
performance of 120/140's varies drastically.
The primary factors are propeller installed
and weight, with rigging coming close
behind. 100-115 mph is the normal range.
With a climb prop, which is good for at
least 100-150 fpm extra climb, expect to be
at the bottom of the speed range. The
cleaner airplanes with a cruise prop will
easily touch the top end, 115 mph. Weight
also changes cruise drastically. It's not
unusual for an airplane to give up 10 mph to
carry an extra person and full fuel.
In cruise, the airplanes
are among the most comfortable and stable of
the breed. Visibility is excellent,
although, with your eyes just barely below
the wings, it's a good idea to raise the
inboard wing to clear before turning. Once
the airplane is "on the step" and trimmed,
it'll fly a straight line until running out
of fuel although it will ride the tiniest
thermals. Of the airplanes of its type, it
is one of the more stable cruisers,
primarily because it is heavier. It also has
some of the best over-the-nose visibility in
cruise. A headset, however, is mandatory for
comfort and hearing protection.
When landing, thermals
aside, the airplane will hold approach speed
reasonably well if trimmed to it. If the
pilot tries to hold speed by hand, rather
than trimming, however, the airplane seems
to want to pick up speed. At 60-65 mph on
final the airplane gives the pilot all day
to set up the approach. Also, compared to
something like a Cub, it is a lousy slipping
machine. In fact, if you don't get the speed
down to around 65, a slip has almost no
effect.
Most 140 pilots don't
bother with flaps on landing because they
have only a marginal effect. They do
increase drag slightly and kill just a
little float. 140A flaps seem more effective
and worth using.
A three-point landing is
almost a non-event, as long as the airplane
touches down straight with no drift. Even if
put on crosswise, however, the airplane just
jumps and jiggles and has little tendency to
swerve quickly. This is one of the strong
points of the spring gear. It is very
forgiving of misalignment on touchdown. Even
if the airplane does decide to head for the
bushes, the rudder is quite effective and a
quick punch is generally all that's needed
to set it straight. It is only marginally
more demanding than a Cub and about the same
as a lightly loaded Citabria.
Wheel landings take a
little getting used to because the airplane
seems so close to the ground. If the pilot
just tries his best to hold the airplane
barely off the ground, letting it find the
runway itself with no help from the pilot,
it will roll on smoothly. If the pilot tries
to "help" it find the ground with a gentle
push, a bounce is in the offing. Fighting
the urge to push is the most important
ingredient of a wheel landing with spring
gear.
The Cessna 120/140 series
has always brought a premium price in the
two-place classic pack for a reason. The
airplane's near-modern utility combines with
a structure that can weather the elements in
outside storage better than most to make it
very attractive. This is an airplane with a
foot in both camps; classic and contemporary
and combines the best of both.
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