A2A Piper Cherokee 180 User Manual
A2ASIMULATIONS
CHEROKEE
ACCU-SIM CHEROKEE 180
ACCU-SIM CHEROKEE 180
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Published by A2A Simulations Inc.
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Ergonomic Advice
▶ Always maintain a distance of at least 45cm to
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low, and the monitor should be tilted slightly backwards, to prevent strains to your cervical spine.
▶ Reduce your screen’s brightness to lower the con-
trast and use a flicker-free, low-radiation monitor.
▶ Make sure the room you play in is well lit.
▶ Avoid playing when tired or worn out and take
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A2ASIMULATIONS
CHEROKEE
ACCU-SIM
CHEROKEE 180
CONTENTS
6
34
36
38
40
44
48
54
PIPER CHEROKEE PA-28-180 AN
AEROPLANE FOR THE REST OF US
CHEROKEE SPRING
DEVELOPER’S NOTES
FEATURES
QUICK-START GUIDE
ACCU-SIM AND THE CHEROKEE 180
ACCU-SIM AND THE COMBUSTION ENGINE
PROPELLERS
58
GENERAL
60
LIMITATIONS
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NORMAL PROCEDURES
68
76
78
86
90
94
102
PERFORMANCE
WEIGHT AND BALANCE
AIRPLANE & SYSTEM DESCRIPTIONS
EMERGENCY PROCEDURES
EMERGENCY PROCEDURES EXPLAINED
AIRPLANE HANDLING,
SERVICE & MAINTENANCE
CREDITS
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PIPER CHEROKEE PA-28-180 AN AEROPLANE FOR THE REST OF US
By Mitchell Glicksman
This flying machine may rightly be called a “Goldilocks”
aeroplane. It is not too big and not too small, not too
complex and not too simple, etc. The Piper Cherokee
180 is, as the little flaxen-haired girl so famously declared, “Just right!”
The entire PA-28 Cherokee line from the humble
two- seat 150 h.p. PA-28-140 to the swi, retractable undercarriage PA-28R-200 Arrow, to the powerful, heavy
load-carrying 235 h.p. PA-28-235 Dakota, is respected as
being one of the most popular, commercially successful series of aircra containing within some of the most
pilot-friendly aeroplanes ever built. Each member of
the Cherokee family fills its particular niche at least as
well as, and oen better than other aircra of similar
type. However, of all of the many Cherokees the Cherokee 180, sitting as it does right in the middle of the pack
has proven itself to be most popular and justifiably so.
Introduced to the public in 1961, the first Cherokee,
the 150 hp PA-28-150 was immediately well-received
setting the pace for its later siblings who went on to
provide pilots of all levels of experience with honest,
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dependable and well-performing aircra which are fun
and satisfying to fly, reliable, safe and economical to
own and operate. However, getting to this place took
some time and some very astute business and aeronautical skills and sense.
HIGH FLYING ON HIGH WINGS
Aer a necessary hiatus during World War II the industry
known as “General Aviation” (GA) which encompasses
all privately (as opposed to government and airline)
owned aircra recommenced in a far better economic
environment, the Great Depression not actually having ended until the U.S. entered W.W.II on December 8,
1941. For the first post-war years of the later 40’s, however, it was very slow going in the GA market. The virtually universally held high expectations that droves of exservice pilots would enthusiastically seek to own their
own aeroplanes turned out to be more than somewhat
optimistic.
As the turbulent and violent early 40s and the uncer-
tain, transitory late 40’s passed into history, and aer
1961 Piper PA-28-150 Cherokee 150
the first three years of the next decade in which a new,
smaller, but no less vicious conflict in Korea came and
went, a new, thriving American middle class began to
enjoy the substantial positive changes engendered by
the new peacetime culture and economy. As the economic boom of the ‘50s began to improve the lives of
so many, all markets, and no less the GA market, began
to grow and thrive as well. By the end of the ‘50s very
few aircra of the pre-war era were still being manufactured; however, in their place promising, new, exciting,
and for those times revolutionary aeroplanes began to
become available.
But old conventions die hard. In the immediate postwar era and for more than a decade most GA aeroplanes
still had wings which sat up atop of the fuselage (known
as the “high wing” design) as they had in the pre - war
years. The prominent post-war manufacturers of GA
aeroplanes, Piper, Cessna, Taylorcra, Stinson, Aeronca, Luscombe and such all exclusively oered aircra
with high wings and, naturally, that was how the public
pictured all GA aeroplanes, all of which they generally
deemed to be “Piper Cubs”.
The prolific and successful high-wing design has a
number of virtues: it is easier to design and build a wing
which does not have to support itself (non-cantilever),
but which may be held up with struts attached to the
wings and the bottom of the fuselage. The high- wing
A real Piper J-3 “Cub”
1948 Stinson 108-2
1947 Luscombe 8a Silvaire
1948 Taylorcraft BC-12d
1950 Aeronca 7AC Champ
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AN AEROPLANE FOR THE REST OF US
Left: 1947 Cessna
190 showing
an unusual
cantilever
high wing
design was also the choice of most GA aircra manufacturers because a strut- braced wing is economical to
build being that it is lighter, thinner, and requires fewer
parts than a cantilever wing. Except for aeroplanes like
the Cessna 190/195 models, the Helio Courier STOL
(short take-o and landing), and the Dornier Do. 27/28,
high-wing aeroplanes of the 50’s were virtually all strut
braced.
Of course, the struts themselves add back some the
weight savings of a non-cantilever high wing and additionally impose a drag penalty which the cantilever wing
design, requiring no support struts, does not. However,
while more aerodynamically clean, the weight penalty
of the heavier and bulkier cantilever wing may be as
great a detriment in its way to overall aircra performance as is the drag coeicient produced by wing support struts. Properly designed, a wing strut’s production of drag may be minimised. Aside from economical
concerns, another of the virtues of a high-wing design is
that the pilot’s and passengers’ are granted an almost
unobstructed view of the ground during flight. In addition, for purposes of visual navigational orientation as
well as for sightseeing, a high wing gives good service.
Today, and since the introduction of the Cherokee
series of aircra in 1961, Piper Aircra has come to be
known as a manufacturer of mostly low- wing GA aeroplanes, the PA-18-150 Super Cub being the lone exception. However, for 24 years, from its founding in 1930,
when businessman and oil speculator William T. Piper
purchased the assets of the bankrupt Taylor Aircra
Company for $761.00, except for a small number of
interesting Piper low-wing prototypes along the way
(PT-1 Trainer-1942, PA-7 Skycoupe-1944, PA-6 Skysedan-1945, and PA-8 Skycycle-1945, none of which went
into production), Piper Aviation had exclusively produced high- wing aircra until the twin-engine PA-23
Apache in 1954. The Taylor/Piper Cub and its progeny,
the PA-15/17 Vagabond, the PA-16 Clipper, PA-18 Super
Cub and the PA-20 Pacer with its variants including the
revolutionary tricycle- undercarriage PA-22 Tri-Pacer
were all high- wing, fabric- covered aeroplanes. The PA22 Tri-Pacer which was introduced to the public as early
as February 1951 predated Cessna’s first tri-gear singles,
the 172 and 182 by five years.
Typical wing struts
1960 Piper Pa-18-150 Super Cub 1954 Piper PA- 23-150 Apache
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Piper Pa-22-150 Tri-Pacer
THE BONANZA BONANZA
Of course, amongst all of this GA high-wing high-jinx
there were a few exceptions with one very strong standout, the remarkably prescient Beechcra Bonanza
Model 35, designed in 1945 and introduced in 1947. Well
named, this aeroplane was a remarkable economic success for Beechcra, the first GA success story of the immediate post-war times. In fact, it was the enormously
positive response to the Bonanza in 1947 that fuelled
many GA aircra manufacturer’s starry-eyed optimism
and belief in the sales boom that never happened.
Designed by Ralph Harmon and his associates in
1945 as the war was coming to an end, Bonanza Model
35 had its first test flight on December 22, 1945. Incorporating what was then known of aerodynamics, aviation
technology and modern manufacturing techniques, its
clean, stressed skin (monocoque) all-metal structure
was reminiscent of the recently lionised Spitfires and
Mustangs and in many ways was a distinct departure
from previous GA aircra. With a retractable undercarriage, V-tail, seats for four adults, constant speed propeller and powered by a simple to manage and inexpensive to run six-cylinder, horizontally opposed, air cooled
165 hp Continental 0-470- E165 engine, it was the first
of a new breed.
In its class and for its time the Bonanza was the
epitome of aeronautical design and engineering — fast,
sturdy, and looking like nothing that had come before.
Sure, it was pricey at the then great sum of $7,975.00
($7,975.00 in 1947 had the same buying power as
$85,165.95 in 2013, annual inflation over this period
being 3.65%), but to its purchasers it was worth every
dime. Upon its introduction, corporations, businesses
and wealthy professionals placed almost 1,500 orders in
advance of its release making the Bonanza an unqualified and immediate roaring success.
While Cessna and many other manufacturers
seemed to be still tied to old, pre-war designs and concepts, Beechcra’s Bonanza was an entirely new breed,
a leap forward that looked like and in every way was
“the very model of a modern” aeroplane. Throughout
the 50’s the Bonanza’s sales continued to soar and its
place at the top of the food chain remained essentially
unchallenged.
1947 Beechcraft
Bonanza Model 35
instrument panel with
50’s style non- “T”
instrument layout and
early classic Narco
“Omnirange” VOR
receiver as almost an
afterthought. Note- no
ILS equipment and
30’s-40’s throwback
throw-over yoke system,
toe brakes only on left
rudder pedals.
Continental 0-470
1947 Beechcraft
Bonanza Model
35 3-view
1947 Beechcraft Bonanza Model 35
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AN AEROPLANE FOR THE REST OF US
1958 Piper PA-24-250 Comanche with one piece windshield and aftermarket spinner
THE BONANZA KILLER
Most painfully cognizant of the Beechcra Bonanza’s
well-deserved success, by the end of the 1950s Piper
Aviation was anxious to produce its own modern, all
metal, retractable undercarriage, high performance single-engine aeroplane. Seeking to enter and to dominate
the high-performance GA business aeroplane market
and unseat the Bonanza, Piper Aviation made ready to
topple the King and to take its place on the GA high- performance throne.
To this end, Piper designed and developed the PA-24
Comanche, “The Bonanza Killer”. Piper Aircra’s ambitious intent was to not only put an end to the Bonanza’s
long- held high-performance single- engine commercial
reign, but to put Piper firmly on the map as GAs leading
and most advanced aircra manufacturer. Piper knew
that to do all of this would require an exceptional aeroplane, one that performed to the highest standards,
was fast, comfortable and safe. Of all, this last requirement was key.
Piper Aviation has traditionally leaned heavily towards flight safety in its designs. Gentle and predicable
stall characteristics, inter-connected rudder and ailerons to prevent inadvertent spins on some models,
slow landing speeds and the like had been regularly
and scrupulously designed into Piper aircra from the
beginning. Accordingly, by the mid 1950s Piper had not
been historically known for producing fast, all-metal,
high-performance aircra; but all that was going to dramatically change before the decade was out.
TAKING THE LOW (WING) ROAD
TO SLAY THE KING
William T. Piper knew that in seeking to enter the highperformance, single-engine business aeroplane market
and challenging the iconic Bonanza that he was he was
taking on a very tough, commercially risky task.
By January 1958 the first Piper PA-24-180-Comanche
was delivered to the public. Its cruising speed at 75%
1960 Piper PA-24-250 Comanche instrument panel with 50’s style
non- “T” instrument layout. As in contemporary Bonanza, radios
seem to be almost an afterthought. Note- modern-style VOR but
no ILS equipment, dual controls but toe brakes on only left rudder
pedals, large ap handle but no Johnson bar brake handle.
1964 Piper PA-24250 Comanche with
unpainted spinner,
aftermarket onepiece windshield
and tip-tanks
1967 Piper PA-24250 Comanche with
3-blade propeller,
aftermarket
spinner, onepiece windshield
and tip-tanks
1959 Piper PA24-250 Comanche
Note- tail low
ground stance,
large nose wheel
and short main
undercarriage legs.
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at 8,000’ is 139 knots (159.85 mph) which in its day was
excellent for a four-seat, 180 hp aeroplane, but not quite
fast enough to seriously compete with the 165 knot
(189.75 mph) 240 hp Bonanza 35H at 75% power.
The first low-wing GA aeroplane produced in over a
decade, the Comanche was something new and exciting. A breathtakingly beautiful design, its novel sweptback tail, its gracefully tapering wings and sleek fuselage gave it the look of innovative modernity in the
same way that Lancaire and the Cirrus aircra appear
to us today.
Accordingly, Piper began to immediately test the
installation of a 250 hp Lycoming O-540 engine in the
Comanche. The PA-24-250, introduced in April 1958 has
a very competitive 75% cruise speed at 8,000’ of 160
knots (184 mph).
So, did the Comanche actually kill the Bonanza?
Well, the answer is clearly, no. However, it did compete
well with it and better in that regard than anything else
in its time. Piper and Beechcra continued to strive
with each other until the Comanche suddenly ceased
production in 1972, along with the excellent, sleek and
speedy Twin-Comanche, as a result of catastrophic
damage to Piper’s Lock Haven, PA factory caused by
the record rising of the nearby Susquehanna River due
to Hurricane Agnes. Today, as newer and even sleeker
modern composite designs vie with it for top dog in the
GA high-performance, single- engine market the Bonanza lives on, albeit in the shape (if not the name) of
the venerable, conventional tail Debonaire, and is still
in production with no end in sight.
While its time in the market as a new aeroplane
was relatively short (1958-72), since its introduction
the Piper Comanche has been and still is one the most
highly- respected and desirable GA aeroplanes. A good
one in good condition is considered a prime find on the
used aircra market. Today there are many thousands
of loyal Comanche adherents who firmly believe, and
with good reason, that it is the most beautiful, elegant
and overall best performing single-engine GA aeroplane
ever built. Right, Scott?
Second test
proto-type of
Piper PA-24-180
Comanche
1958 Beechcraft
Bonanza H35
with tip-tanks
1959 Beechcraft
Bonanza 35J
Lycoming 0-360
Piper PA-24- 250 all original contemporary Beechcraft Bonanza G36Piper PA-30- 160 Twin Comanche - R. I. P.
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AN AEROPLANE FOR THE REST OF US
HOW ABOUT AN AEROPLANE
FOR THE REST OF US?
Without any question, the Bonanza and the Comanche
were and are very high performance single-engine GA air
cra aimed at distinctly well-heeled potential private/corporate owners. However, there also existed a significant
segment of the GA market that wished to own a new, rea
sonably fast (if not the fastest), modern, all-metal, fourseat aeroplane, but who could not aord the Comanche’s
and especially the Bonanza’s high price tag. FBOs (fixedbase operators), flight school operators and flying clubs
were also looking for aircra that they could rent out at
rates that the average weekend private pilot could aord.
As the prosperous second half of the 1950s came to a
close, Piper understood that the time of the fabric- covered Tri-Pacer and Colt had come to its end. Studies within Piper Aviation in the mid- 50’s showed that with modern manufacturing techniques it was actually now more
cost-eective to produce an all-metal aeroplane than to
continue to produce the old school parts and labour- intensive, metal frame, fabric- covered Tri-Pacer and Colt.
Even with plans to build the Comanche already
drawn, the factory tooling up to manufacture it, and
with Piper’s well-founded hopes and expectations that
its new beauty would well-establish Piper Aviation in
the high-performance single-engine, business aeroplane market, William T. Piper knew that if Piper was going to survive and flourish into the next decade and beyond that, further aeronautical invention and progress
was wanted. He, his son Pug and the entire Piper team
knew that they had to produce a new, modern entry to
mid-market level aeroplane as soon as possible in order
to compete with Piper’s true rival, the only other major
aircra company that was actively and successfully servicing that segment of the GA market, Cessna.
Immediately upon the introduction of the all- metal
Cessna 172 in 1956 Piper knew that its internal evaluations regarding the obsolescence of fabric-covered aircra were indeed valid and that their then single-engine
star, the Tri-Pacer, had already been eclipsed. While the
exceptional Comanche had, in fact, turned out to be
highly competitive in the high-end GA niche, giving the
equally exceptional Beechcra Bonanza a good run for
the money, Piper well understood that in order to compete in and command a viable position in the entry/
middle price market it needed to oer something new,
-
-
Rib- stitching a
fabric covered
Tri-Pacer’s
wing before
doping —
one of this
process’s
many labourintensive steps.
something that would give potential owners an attractive alternative to Cessna’s popular 172.
Looking to produce a four-seat design which would
be simpler and which could be produced less expensively than the complex, retractable gear, constant- speed
propeller Comanche, Piper also knew that in order to be
competitive in the lucrative trainer market they needed
to build a replacement for the two- seat Colt which had
been commercially greatly overtaken by the all metal
Cessna 150. If these two needs could be resolved by one
overall design, so much the better.
A product of the prosperity and economic confidence
of the late ‘50’s in the United States was a wave of new
student pilots. Flight schools and clubs were popping
up at virtually every local airport and business was very
brisk. Since its introduction in 1958, the all-metal, twoseat Cessna 150 had become by far the most popular
aircra in this burgeoning trainer market. As the last of
the J-3’s, Aeronca Champs and other similar tail-wheel
(then called “conventional undercarriage”) aircra
began to disappear from attrition mostly due to tailwheel induced taxiing and landing accidents, they were
quickly being replaced by the tricycle undercarriage 100
hp Cessna 150 and, to Piper’s disappointment, to a far
lesser extent the 108 hp, two seat version of the old TriPacer, the fabric- covered Piper Colt. It was understood
that the old tail- wheel trainers did not oer as relevant
a training experience to student pilots who looked for-
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1961 Cessna 172
A2ASIMULATIONS
1959 Cessna 150
1960 Piper PA-22-108 Colt
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1956 Cessna 172
1956 Cessna 172 interior
ward to soon flying higher performance aircra, all of
which had tricycle undercarriages.
Also, unlike the J-3, etc. where the student and instructor sit in tandem, in the new trainers the instructor and
student sit side- by- side, facilitating communication as
well as increasing the confidence of the student and mak
ing it easier for the instructor to demonstrate maneouvers
and to teach the lesson. Additionally, and most signifi
cantly for FBOs, flight schools and clubs, with the advent
of these new tricycle- undercarriage trainers, ground
loops and nose overs whilst landing as well as collisions
whilst taxiing became a thing of the un- mourned for past.
The Tri-Pacer shared the same market as Cessna’s
172; however, except that they were both high-wing,
four place aeroplanes of similar power, they actually
shared few similarities, particularly with regard to construction and appearance.
Firstly, the Tri-Pacer was fabric covered whilst the
172 was all metal. The higher maintenance cost of a
fabric covering as well as the anticipated expense of an
inevitable fabric re-covering was a strong market motivator toward the all- metal l72.
Secondly, the Tri-Pacer’s frame has many steel components within which can and do rust, and eventually cause
major repair headaches. The 172’s stressed-skin covered
airframe is sturdy, low- maintenance and is all aluminium.
Thirdly, the Tri-Pacer, which had been introduced
in 1951 was distinctly showing its age and was, in fact,
something of an anachronism by the beginning of the
following decade. Its foreshortened appearance gave it
a somewhat stodgy look and sitting seemingly precariously upon its closely spaced undercarriage, it garnered
the unfortunate nickname “Flying Milk Stool”. Piper
-
had to face it; the Tri-Pacer just didn’t imply a clear and
definite sense of modernity as surely as the Cessna 172.
-
Taking everything into consideration, Piper saw the
writing on the wall.
Ironically, the Tri-Pacer’s performance is excellent,
competing well with and in some instances beating the
newer Cessna 172. The 160 hp Tri-Pacer climbs at approximately 800 fpm loaded at or near MGW with a top speed
of 123 k (141.5 mph) and a 75% cruise of 117k (134.5 mph)
at 7,500’. Its useful load is 890 lbs., and its take-o and
landing performance as well as its slow and departed
flight performance is overall better than the 172’s. The
Tri-Pacer is more responsive than the Cessna 172 and
many pilots have found it to be more fun to fly. Nevertheless, by the end of the 1950’s the more modern-looking
Cessna 172 was running away with the middle GA market.
Before 1961 one might well be excused for thinking
that with the exception of the low-wing twin-engine
Apache, the Comanche and the Pawnee crop-duster
that Piper leaned heavily towards the production of
high-wing aeroplanes. Aer three decades and thousands of fabric-covered, high- wing Pipers this trend
changed dramatically, marking the end of one era and
1959 Piper PA22-150 Tri-Pacer
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1967 Cessna 172/Skyhawk
1960 Piper PA-25-235
Pawnee crop duster
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AN AEROPLANE FOR THE REST OF US
Left: Fred Weick’s
brilliant and
innovative 1936
Erco 315CD
“Ercoupe”
Center: Very
rare photograph
of experimental
retractable
Ercoupe
Right: Fred
Weick with his
Ercoupe Noteconstant speed
propeller with
anti- icing boots
the beginning of a new one when the first of the all metal low-wing PA-28-150 and PA-28-160 Cherokees were
introduced to replace the Tri-Pacer and the Colt which
were then withdrawn from production.
CREATING AN AFFORDABLE LEGEND
In 1957, Karl Bergey, Assistant Chief Engineer at Piper’s
brand new Vero Beach facility which was built to design,
test and ultimately manufacture the Cherokee, led the
team of engineers and designers whose task it was to
create an aeroplane that would establish the new, modern Piper Aviation in the present and secure it well into
the future. Pug Piper sought to create a small team of
engineer/designers who had reputations for having the
foresight and imagination to create something new. To
that end, Pug Piper’s friend, the talented, progressive
and imaginative 1928 Collier Trophy winner, Fred Weick
was invited to join the team.
Weick was one of the first American aeronautical engineers who had, among other things, worked closely with
the United States Postal Service in the early 1920s to establish and to develop the U.S. Air Mail Service. In 1925,
whilst an engineer working for the National Advisory
Committee for Aeronautics (NACA), Weick was the chief
design engineer and responsible for developing streamlined cowlings to improve aerodynamic eiciency while
enhancing engine temperature control. He also helped to
design the first full-scale propeller wind tunnel.
By 1936, as chief designer at ERCO, Mr. Weick designed the revolutionary ERCO 310, better known as the
“Ercoupe”, designed to be virtually stall and spin-proof
with integrated rudder and aileron controls (no rudder
pedals), a crosswind resistant undercarriage, and one of
the first aeroplanes designed with a tricycle undercarriage.
Both William Piper and his son, Pug greatly admired
the extraordinary talents of the brilliant and prolific
aeronautical engineer/designer John W. Thorp who
agreed to join the team. In the course of creating the
Cherokee this stellar design team found Thorpe’s keen
aeronautical mind to be a great and powerful resource.
The design of the Cherokee ultimately greatly benefited
from many of John Thope’s ideas and from his excellent
past designs. In particular, the team incorporated many
features from Thorp’s amazingly ahead of its time, the
1945 all- metal T-211.
A MOST DELICIOUS WING
The first thing that Pug Piper told his team was that the
new aeroplane would have a low wing for a new Piper
look and so that drag producing struts of any kind could
be avoided. He wanted Piper Aviation to build on the
excellent reputation that the low-wing Comanche had
already established and envisioned an aeroplane that
would look and be as entirely dierent from the Cessna
172 as possible.
John W. Thorp
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1945(!) Thorp “Skyshooter” T211 showing the true
genesis of the Cherokee design. Note the Hershey
Bar wing, undercarriage conguration, corrugated
skin rudder and the stabilator with anti-servo tab.
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An all metal, cantilever 160 sq. . (15.14 m), 30’ (9.2
m) span, 5’ 3” (1.6m) constant-chord (non-tapering)
wing, popularly called the “Hershey Bar” wing because
of its similarity in shape to that most famous rectangular confection, became the basic platform upon which
this new aeroplane was built. This wing’s aspect ratio
(span divided by chord) is on the low side at 5.63. This
was not a problem or a new situation at Piper. The immediate predecessors of the Cherokee, the so- called
“short wing” Pipers, the Vagabond, the Clipper, the Pacer, the Tri-Pacer and the Colt which the Cherokee series
of aircra was to replace had even lower aspect ratios.
By comparison Cessna 172’s aspect ratio was 7.448.
It was a deliberate design choice to raise the new
Cherokee’s wing’s aspect ratio a bit from the shortwinged Pipers in order to increase its Cl (coeicient of li)
and thereby its eiciency. Up to a point, a higher aspect
ratio wing promotes better high altitude cruise, climb
and glide performance. However, a wing with a lower aspect ratio has at least one advantage — it has a higher
critical angle of attack (Alpha), i.e., the positive Alpha
at which it will stall; additionally the stall itself tends to
be gentle. The old short-wing Pipers were not very eicient power-o gliders (I recall that the Colt, particularly,
glided like a stone); however, they were extremely forgiving at low airspeeds and in extreme departed flight attitudes. They could, with suicient power applied, seem to
“hang on their propellers” with their noses sitting way up
in the air whilst flying at very low airspeeds. It had been
Fred Weick’s lifelong goal to build aeroplanes such as the
Ercoupe that were easy to fly and by extension, safe. All
agreed that forgiving flight characteristics would be a
most attractive feature to the low-time pilots and FBOs
that were Pipers commercial target.
The team designed the Cherokee’s wing to be
mounted at an angle of +2º to the fuselage’s longitudinal datum line in order to permit a distinctly nose-down
attitude, thus promoting good forward visibility for the
aeroplane’s occupants on the ground and in flight, and
Aspect Ratio - wing
span (tip to tip) divided
by average chord
reducing P-eect (combination of twisting slipstream*
and induced propeller yaw in the opposite direction of
the turning of the propeller when at positive Alpha) during the takeo run. They wanted to improve upon the
Comanche’s distinctly nose-high stance on the ground
which creates a good deal of P-eect on takeo requiring lots of right rudder to keep it on the centreline.
*For what it’s worth, this writer does not hold very
much with the theory of a twisting slipstream as a major
P-eect force for a number of reasons to lengthy to go
into here. Also, remember, P-eect operates in the yaw
axis, torque in the roll axis.
Being a low-wing aeroplane, the Cherokee’s overall
vertical centre of gravity (C.G. v) is low, however, it is
necessarily at a point above its low wing. This promotes
poor stability in the lateral (roll) axis while enhancing
maneouverability. While enhanced maneouverability is a good thing in a fighter, aerobatic show or sport
aeroplane, it is not necessarily so good in an aeroplane
Left to right:
1) Piper PA-16
Clipper
2) Piper PA- 17
Vagabond
3) Piper PA-22
Pacer (Tri-Pacer
in red above)
4)1964 Piper
PA-28-140
showing original
“Hershey Bar”
rectangular wing
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Angle of Attack (AOA) also called “Alpha”
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Hershey Bar Cherokee showing 7 degrees of dihedral
Cessna 172 showing 3.5 degrees dihedral
designed to be used for training new pilots and for comfortable and easy touring. To create good lateral stability a low- wing aeroplane requires dihedral, more dihedral than is required for a high wing aeroplane. Also, a
low wing aeroplane requires greater dihedral to provide
for adequate wingtip clearance when on the ground
and when a wing may be lowered during a cross-wind
landing. Accordingly, the Cherokee’s low wing has 7º of
dihedral which gives it very good lateral stability which
is especially welcome on long trips and when in mildly
turbulent conditions.
The vertical centre of gravity (C.G. v) of a high-wing
aeroplane is also low, but at a point below the wing
which promotes good stability in the lateral axis. This
means that less dihedral is required for high-wing aeroplanes. Accordingly, the high wing Cessna 172’s dihedral
is only 3.5º.
Dihedral causes a self-levelling force to occur when
the aeroplane is displaced from level in the roll axis. As
any force, such as turbulence, begins to roll an aeroplane from level, the downward moving wing’s Alpha
increases, creating li. In addition, the lowered wing assumes a more horizontal attitude than the higher wing
and, concurrently, the lower wing creates more li because of this, as well. Both of these eects tend to roll
the aeroplane back towards level.
Of course, too much dihedral can lead to a reduced
roll rate as well as over-sensitivity in turbulence, making for an uncomfortable ride in all but the calmest air.
Compensating for its generous dihedral, the rectangular wing Cherokee’s large and most eective ailerons
produce a rapid roll rate which is faster than that of
most GA aeroplanes. This is due in part to the reduced
lateral damping eect of the low aspect- ratio, slightly
foreshortened Hershey Bar wing. The Cessna 172’s
wingspan is 6’ greater than that of the rectangular wing
Cherokee and, accordingly, it creates more lateral axis
damping which somewhat reduces its roll rate. Accord-
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ingly, the Cherokee is maneouverable, laterally stable
and rides quite well in all kinds of turbulent air. Accordingly, it seems that the Cherokee’s wing’s dihedral, like
so much else about this aeroplane, appears to be just
right.
Adverse yaw is the tendency for an aeroplane’s nose
to yaw in the opposite direction of bank and is caused
by the rising wing pulling back because of increased
induced drag created by li. To reduce adverse yaw,
virtually all modern aeroplanes, including the Cherokee, have ailerons which are dierentially rigged; that
is, there is more upward aileron movement than down,
causing there to be less li- induced drag in the rising
wing and thereby reducing its tendency to yaw the aeroplane away from the turn.
To simplify the Cherokee’s construction and to keep
costs to a minimum, a few new wing mounting techniques were incorporated. As mentioned, the Comanche’s le and right wings are joined in the middle in the
factory making the wing one piece. The entire wing is
then attached to the bottom of the fuselage, the main
spar being bolted to a receiving 3-sided box. This construction makes for a very strong +7g wing, perhaps
stronger than necessary in a non-aerobatic GA aeroplane. It is also quite costly. Piper’s team looked for another way to mount the wing to the fuselage that would
be strong enough but also simple and economical.
What they came up with is this: The Cherokee’s wings
are attached individually to each side of the fuselage.
Each of the Cherokee’s wings’ main spar is in the form of
an “I” beam which is inserted into to a box beam built as
a part of the fuselage frame located under the rear passenger’s seat, spanning the width of the fuselage. Once
the wings’ spars are seated within the box beam they
are secured with eight heavy bolts essentially making
the wing one piece. The inner ends of the forward and
a wing sub- spars are bolted to the fuselage through
matching mounting plates in the wing root and on the
fuselage. This greatly simplifies assembly as well as
making major wing repairs or replacement less expensive. An additional plus is that this method of mounting
the wings separately permits the use of a much shorter
shipping crate, thus saving transportation costs of the
unassembled airframe.
Piper reports that it has thoroughly tested the Cherokee’s wing mounting system, running at least 480,000
load and unload cycles with no damage to the wing
mounts.
The Cherokee’s constant-chord, rectangular wing
planform did not, however, come about without some
friction and dissent within the design team. “Pug” Piper
wanted tapered wings as on the Comanche, both for
aesthetic and aerodynamic reasons. Both Thorp and
Bergey also initially thought that a tapered wing for
the new aeroplane would be best even though Thorp,
in particular, had been a long-time, outspoken advocate of non-tapered wings for GA aircra (see the Thorp
T-112).
Supermarine
Spitres showing
elliptical wings
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The team considered a tapered wing for three basic
reasons:
At first, Karl Bergey was, as was his boss, Pug Piper,
in favour of a tapered wing for the new design which he
said more closely emulated the commonly accepted
ideal wing plan form, the ellipse, as found on R. J. Mitchell’s spectacular and beautiful Supermarine Spitfire.
Piper, Bergey and Thorp initially agreed that an elliptical wing produces less overall li-induced drag than a
rectangular wing and is quite eicient.
The second argument for a tapered wing was that
since the tapered outer part of the wing has a shorter
chord it has less overall area than the inner part of the
wing. This reduced wing area would cause less upward
bending pressure on the root of the wing when in flight
than if it the chord was constant to the tip. With less
bending to worry about, a simpler, lighter inner wing
structure could be designed.
The third and perhaps the most practical reason for
a tapered wing (from a marketing perspective at least)
was that they look sleek and aerodynamically “correct”.
Always most aware of the importance of marketing with
regard to of any commercial product, Pug Piper, as had
his father so many times before him, found this argument to be highly persuasive.
It looked like the Cherokee was going to have a tapered wing similar to the Comanche’s when Thorp began to advocate for a rectangular wing instead. Aer
ruminating about the issue for a while and he began to
discount the structural argument for a tapered wing. He
reasoned that the dierence in the structural weight of
a tapered verses rectangular wing of the same size was
too small to consider. Combining this with his aerodynamic analysis he said that aerodynamic scale eect
makes it possible to use a smaller rectangular wing
(rather than a larger tapered wing) for a given stalling
speed. He went on to explain that therefore the tapered
wing, though possibly inherently slightly lighter, must
ultimately be of greater span in order to provide equal
wing area to that of the un-tapered wing, thereby erasing any weight saving.
As to the elliptical wing planform theory, Thorp rejoined Piper and Bergey’s opinions and held that there
was more to the issue than that so- called “ideal”.
He argued that while the total of aerodynamic forces
indeed seemed to favour an elliptical wing form, where
the wing’s chord was shorter near and at the tip of such
a wing, or in any tapered wing seeking to emulate an
elliptical form, the Reynolds Number (RN)* is similarly
lower near and at the wing tip, therefore causing a great
propensity for the wing tip to stall before the rest of the
wing.
Reynolds Number =
V(speed) x L (length of chord)
Kv (kinematic viscosity)
“stickiness” of the air. For simplicity you can use the
value 6327 for the Kv of air at the standard temperature
of 59 degrees Fahrenheit at Sea Level. The speed value
is in feet per second and the length is the chord of the
wing in linear feet.
The Reynolds Number is an essential measurement
of wing/aircra performance and if you are a serious
student of aerodynamics you will want to know a good
deal about it.
The others recognized Thorp’s argument to be sound
because, as is well-known, where the RN is lower the
maximum Cl is necessarily lower, creating less li at
any given airspeed as compared to any other part of the
wing where the chord is longer. Accordingly, it follows
that where the maximum Cl is smaller, that part of the
wing must stall first.
Thorp further argued that the relatively small size
of GA aircra’s wings and their relatively slow takeo
and landing speeds exacerbates the tip stall problem
in a tapered or elliptical wing as the outer wing’s RN is
therefore even lower. Additionally, a tapered or elliptical wing is more readily likely to have reduced aileron
eectiveness. While it makes sense that the aileron on
a tapered wing may be less eective being mounted
at the tapered portion of the wing which has a shorter
chord and thus a lower RN causing lower eiciency and
Without getting too deep into the math of this for-
mula, the kinematic viscosity (Kv) is a measure of the
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AN AEROPLANE FOR THE REST OF US
Some xes
for tip stall
a lower maximum Cl; it is also true that the tapered
wing’s outer section produces less aerodynamic lateral
damping force in a roll than does a constant chord wing.
Therefore, all else being equal, with properly designed
ailerons a tapered wing could have as fast or a faster
rate of roll than a constant chord wing of identical area
and span.
As a tapered wing for the Cherokee was being seriously discussed, the various known “fixes” for tip stall
were considered. The commonest of these is wing twist
or “washout” where the outer portion of the wing’s trailing edge is built to ride slightly higher than the leading
edge (producing lower local static Alpha). Additional
preventative measures for tip stall are aerodynamic devices which are attached and/or added to the wing such
as drooped or enlarged leading edges, stall strip at leading edge, more greatly cambered (curved) outer- wing
airfoil sections, fixed or automatic leading edge slots or
slats, and downward curved wing tips.
While these fixes do help the problem to some degree, they all add complexity, and/or weight to the
wing and all produce additional airspeed- robbing drag
which tends to negate the advantage that the tapered
wing was supposed to deliver in the first place.
In final analysis, Thorp, Bergey and Weick (who ad-
Piper PA-28-161
showing semitapered wing
PA-28-181 Archer
showing semitapered wing
mired Thorp’s sound reasoning on the matter) agreed
that nothing of any value, especially airspeed, would be
gained by incorporating a tapered wing, and admitted
that, in fact, the tapered wing in its pure “unfixed” form
was more prone to tip stalls and spins. They agreed that
a rectangular wing with a few degrees of washout would
be as or more eicient as an elliptical or tapered wing
without any of the tapered wing’s attendant tip-stall
problems and without the complexity and additional
expense of building a more complicated tapered wing
structure.
The team finally agreed upon a rectangular, constant- chord, “Hershey Bar” wing for the Cherokee,
which indeed proved to possess a high degree of cruise
eiciency, near to ideal li distribution characteristics,
and which is highly stable at low airspeeds, near-stall,
stall and departed flight conditions.
Always seeking to improve the Cherokee, in 1969 an
extension of the wing span was proposed in order to improve load carrying ability and rate of climb. However,
preliminary tests showed that a longer wing would necessarily increase positive bending pressure on the wing
root and inboard wing structure requiring an entirely
new and more robust inner wing design which would
necessarily add to manufacturing costs. The idea was
tabled for the time being.
In 1973 Piper revisited the Cherokee’s wing design
and decided to go with the original idea of a tapered
wing. While Thorp and Weick’s original theories regarding tapered vs. rectangular wings were correct and had
been well-proved, much to the dismay of many within
and without Piper Aviation, a new, tapered wing was approved for the PA-28-150.
This aeroplane also incorporated a few other upgrades, improved wing fairing and seals and was renamed the PA-28-151 “Warrior”. Thereaer, if a Piper
aeroplane has a “1” as its last number, as in PA-28-151,
etc. it has a semi-tapered wing. The “Warrior” broke Piper’s tradition which began in 1954 with the twin engine
Apache of exclusively naming its aircra aer the English language names of Native American tribes, and began a new tradition of also naming aircra using words
such as “Tomahawk”, “Arrow”, “Archer”, “Papoose”, etc.
that closely suggested and alluded to that noble culture.
The new PA-28-151 was very similar to the old PA-28150, except for its tapered wing, which is actually only
tapered from the mid - span point to the tip on each side
and therefore ought to more properly be called “semitapered”. The new wing was also increased by 5’ in
span to make up for the decreased area of the tapered
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section, as Thorp had said would be necessary. The increase in span raised this new wing’s aspect ratio to 6.66
from 5.63 and likewise slightly raised its Cl. The product
of the additional span is a slight gain in rate of climb and
high altitude cruise speed and a flatter power-o glide.
Some of these performance gains were initially credited solely to the new semi- tapered wing itself; but
upon closer inspection and analysis it was discovered
that they were at least partially, if not mostly due to the
improved wing/fuselage seals and fairing incorporated
in the PA-28-151. At the same time, the semi-tapered
wing’s increased aspect ratio, which in addition to its
said performance enhancements also reduces the eective range of Alpha at which the Cherokee may fly before
stalling. This causes the semi-taper wing Cherokee’s Alpha at the stall to be lower than that of the Cherokee
with a rectangular wing.
In 1976 the PA-28-180 was re-designed with a semitapered wing becoming the PA-28-181 “Archer”; and by
1979 all Piper single- engine aircra had received semitapered wings, all of them, accordingly, both gaining
and losing therefore as mentioned above.
As far as performance goes between the Cherokee
with a rectangular or semi-taper wing, all else being
equal and without wheel pants, from sea-level to approximately 6,000’ the rectangular wing is actually faster than the semi-tapered wing. However, as altitude increases past 6000’ the rectangular wing loses airspeed
more rapidly. As mentioned, the semi-taper wing Cherokee has a slightly better rate of climb and also a flatter
glide. Flatter glide is good in itself, but has a down side
in that the semi-tapered wing Cherokee is more sensitive to airspeed when landing than is the rectangular
wing. This means that if there is any amount of excess
airspeed at the flair, the semi-tapered wing tends to
float a while before touching down where the rectangular wing settles down more quickly and with less float.
Whatever the reasons may be, the semi-taper wing’s
performance increases are very slight. This writer, having flown both versions of Cherokees prefers the rectangular wing over the semi-tapered wing for its speed,
sprightlier handling and its excellent landing, low-airspeed and stall characteristics; or perhaps it’s also out
of a sense of tradition and nostalgia.
Hershey Bar vs. semi-tapered wings
FOILED AGAIN
Aer careful analysis, the team selected the rather thick
at 15% NACA 652-415 laminar-flow airfoil as it was highly eicient at the airspeeds and altitudes at which the
Cherokee was expected to cruise while still preserving
good low airspeed characteristics and a most gentle,
benign stall.
This airfoil is an NACA “6” series airfoil, has its area
of minimum pressure 50% of the chord from the leading
edge, maintains low drag at 0.2 above and below the li
coeicient of 0.4, has a maximum thickness of 15% of
the chord, a= 0.5 means that the airfoil maintains laminar flow over 50% of the chord.
Despite the NACA numbers, the Cherokee’s wing’s
thickest point is actually closer to 40% back from the
leading edge.
Just a quick word or two about airfoils and what a
“laminar flow airfoil” is. The wing’s airfoil is its crosssection shape from leading to trailing edge and is primarily and most importantly an air diverter*. Among
other things, the airfoil diverts the air through which an
aeroplane’s wing travels downwards at the wing’s trailing edge so that li may be generated (see Newton’s
Third Law of Motion). In order to do this the “boundary
layer”, which is the very thin, viscous layer of air closest
to the surface of the wing, must adhere to the wing and
not become turbulent or detach from the surface of the
wing. As long as the boundary layer adheres smoothly
and uninterruptedly to the surface of the wing, the wing
will continue to divert air downward at the trailing edge
and thereby produce li.
*There are many theories of li, some traditional,
some imaginative and seemingly intuitive. However, in
recent years most of the traditional theories have been
discredited as they were found to be flawed, entirely
improbable or simply wrong as aeronautical knowledge
and understanding has progressed. It is most likely that
there are numerous ways in which a wing produces li.
The airfoil as a downwash “air diverter” at the trailing
Cherokee wing
root without ap
or aileron, “wet
wing” fuel tank
removed (leading
edge facing left)
This is the
Cherokee’s airfoil
straight black
line- chord
curved grey line mid line or mean
camber line
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edge is and has for many years been what this writer
thinks is the most probable correct theory. Of course,
the true scientific mind must always be open to new
facts and disclosures. This writer awaits with great interest what is yet to be discovered.
Also, a smooth and adherent boundary layer produces minimum pressure and/or parasite drag enabling
the aeroplane to fly faster for any given amount of power. Slight micro-turbulation in the boundary layer actually increases its adherence to the surface of the wing;
but, when this turbulation becomes more severe and
becomes a turbulent flow, li is reduced and pressure
drag increases. If this turbulence becomes too severe,
which typically happens at critical positive Alpha, the
turbulent boundary layer detaches from the surface
of the wing creating random eddies and vortices causing considerable parasite and pressure drag to be produced. Upon boundary layer flow separation from the
surface of the wing the former downward diverted air
flow ceases and, concurrently, the wing ceases to generate li. This is the “stall”. An airfoil designed to produce
maximum uninterrupted, adhesive boundary layer flow
at the surface of the wing and minimum drag is called a
“laminar flow airfoil”.
Laminar Flow
NACA NUMEROLOGY
The first number, “6”, of NACA 652-415 indicates that
this is a NACA “6-series” airfoil. The second number, “5”,
indicates the position in percentage x 10 of the chord
(leading to trailing edge) where minimum pressure occurs — here indicating the 50% chord position. Minimum pressure usually occurs at the thickest part of the
airfoil.
The subscript “2” indicates that this airfoil’s drag
coeicient approximates its minimum value between
plus or minus 0.2 of the airfoil’s design Cl. The NACA
65(9)-415 airfoil which is a later refinement of the NACA
652-415 has been used in the Cherokee as well, the only
dierence between it and the NACA 652-415 being that
in the latter airfoil the airfoil’s drag coeicient approximates its minimum value between plus or minus 0.9 of
the airfoil’s design li coeicient.
The number “4” indicates the li coeicient in
tenths; here, 0.4.
The last two numbers, “15”, indicate the wing’s maximum thickness as a percentage of the chord; here, 15%
of the chord.
A laminar flow airfoil is typically designed so that its
thickest point is usually at approximately 50% of the
chord. A normal airfoil’s thickest point is usually at approximately 25% to 33% of the chord. The laminar flow
airfoil shape combined with a very smooth wing surface
best promotes a smooth and adherent boundary layer.
The North American P-51 “Mustang” was the first mathematically designed aeroplane and its wing was the first
to be deliberately designed with a “laminar flow” airfoil,
however, even a very slight ripple or bump in or on the
surface of the wing can prevent the true laminar flow effect. Despite all good intentions the P-51’s wing surface
is not suiciently smooth and uninterrupted nor was
it optimally built or usually suiciently maintained in
the field to promote true laminar flow. The Cherokee’s
wing surface, however, is actually far smoother and if
kept scrupulously clean, promotes a stable, adherent
boundary layer very well.
A salient characteristic of the Cherokee’s airfoil is
that it has a fairly flat Cd (Coeicient of Drag) curve and
thereby looses li very slowly as the stall is approached.
Unlike many others, this airfoil does not possess a single
critical angle of attack (positive Alpha) at which it will
stall. The NACA 652-415 airfoil flies within a fairly broad
range of positive Alpha and does not break sharply at
the stall unless very aggressively forced into an extreme
positive Alpha condition called a “deep stall”. Spins
are likewise very diicult to enter unless aggressively
pursued. Additionally, the Hershey Bar wing’s low 5.63
aspect ratio helps to promote the Cherokee’s distinctly
anti-stall/spin behaviour. That these gentle stall/spin
characteristics were incorporated in the Cherokee’s design is no coincidence and very much in keeping with
Fred Weick’s life-long design practices, particularly with
regard to his Ercoupe design which, as mentioned, was
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Simple Polar showing relative differences between
high and low aspect ratio wing (here - AR)
specifically designed to be virtually stall and spin-proof.
Those who have flown a Cherokee will surely attest
to its remarkably benign handling at low airspeed and
its reluctance to stall or spin. In fact, at one “g” with
power o it does not really break at all at the stall, but
merely oscillates gently forward and a while descending rapidly, which is the only indication that the wing
has in fact stalled. Pilots generally find the Cherokee to
be reluctant to stall with power on; although in this configuration the stall break may be a bit more definite with
the le wing falling due to engine torque at high power.
With power on the Cherokee rarely loses aileron control.
This is a sharp contrast to the Cessna 172 which loses
aileron control quite readily when near or at the stall.
These stall characteristics apply to both semi-tapered
and rectangular wing Cherokees, the rectangular wing
being the more benign and reluctant to stall due to its
higher Alpha before stall due to its lower aspect ratio.
Because the Cherokee’s NACA 652-415 laminar-flow
airfoil’s thickest point is near the wing’s mid-chord, approximately 40%, the main wing spar is located farther
a than is possible with non-laminar airfoils. Accordingly, as the main wing spar runs longitudinally across
the wing at its thickest point, its profile is deep and
great strength is gained therefrom. Also, the location
of the main spar so far a locates it under the rear passengers’ seat, permitting the cabin floor to be flat and
unobstructed.
surface is displaced and is more eicient than a conventional fixed stabiliser and hinged elevator. Accordingly,
it may be of less overall area than a similar conventional
fixed and hinged pitch control surface. Accordingly, the
early Cherokees’ stabilator was designed to be approximately two feet shorter in span than later ones making
these Cherokees with shorter stabilators slightly less effective in pitch control, particularly at slower airspeeds.
An anti-servo tab is located at the trailing edge of the
stabilator, similar to a trim tab; however an anti-servo
tab is mechanically linked to the stabilator to move in
the same direction as the stabilator when the stabilator is displaced by the pilot. This provides a proportional opposing force to the displaced stabilator, thus
avoiding negative aerodynamic stability (the tendency
of a balanced, moving, aerodynamic surface to deflect
further as it is displaced from neutral) and which, by
increasing the load on the stabilator as it is displaced,
prevents over- sensitivity in the pitch axis control system at all airspeeds.
In the Cherokee pitch trim is controlled by changing
the angle of the entire stabilator and anti-servo tab. At
the time that the Cherokee was being designed the allflying anti-servo stabilator was already a well-proved,
smooth and highly eicient pitch control system which
possessed the additional properties of being lighter
and, as mentioned, producing less overall drag than
Cherokee
showing
stabilator and
anti-servo tab
KEEPING THINGS STABLE
Following the successful Comanche design, instead of
the usual horizontal rear flight surface consisting of a
fixed stabilizer with a hinged elevator, the Cherokee incorporates a one piece, all- flying “stabilator” with an
anti-servo tab (also called an anti-balance tab) upon
which, not likely coincidentally, John Thorp holds the
patent. A one-piece (i.e. non-hinged), all moving stabilator pitch control surface produces less drag when the
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An antiservo
tab attempts
to streamline
the control
surface and is
used to make
the stabilator
less sensitive
by opposing the
force exerted
by the pilot.
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How a
stabilator with
anti-servo
tab works
the usual hinged stabilizer and elevator. A stabilator/
anti servo tab horizontal surface very similar to that
which was incorporated in the Cherokee appeared on
John Thorp’s 1945 T11 and T211. While Thorp’s original
design for the stabilator was innovative and eective,
it was also a bit complicated as to linkages and such.
Ever seeking to economise on production costs, Piper’s
Assistant Chief Engineer Karl Bergey modified Thorp’s
system and was able to simplify it while still bestowing
its essential benefits on the new aeroplane.
Speaking of pitch trim, early Cherokees followed
Piper’s unique method of elevator trim control, a horizontal hand-crank and position indicator located in the
ceiling between the front two seats. Tri-Pacers, Colts
and the first Comanches have the same control. It works
fine except that even though it is well-marked, many pilots (me too) have a devil of time remembering which
direction to turn the handle for up or down trim. BTW,
it’s clockwise for up and anti-clockwise for down.
SWEPT AWAY
We might as well get it out of the way here — the swept
back rudder and fin — does it serve any useful aerodynamic purpose as opposed to a straight tail or was it
merely intended to sweep customers o their feet with
a sweeping new design? (apologies)
Piper had incorporated a swept vertical tail on the
1958 Comanche, which this writer believes is the first time
such appeared on any mass-produced GA aeroplane. The
Beechcra Debonaire with its swept rudder and fin was not
introduced until 1960. Having innovated this feature, Piper
made it a priority to incorporate it as a signature design
on its next and subsequent Piper aeroplanes. In any event,
the aeroplane that Piper was most competitive in the GA
entry/middle market, the 1960 Cessna 172A, now had one.
In the late 50’s a swept vertical tail on a GA aeroplane was
new. It certainly looked modern and streamlined and sug
gested the tail surfaces of jet fighters and all. The marketing strategy went something like this: Everyone knows that
jet fighters go fast and that they have swept back surfaces;
so, if your Piper has a swept back rudder/fin similar to a
jet fighter, well then, it ought to go fast as well, right? Of
course, the swept surfaces on jet fighters have much to do
with trans-sonic and super-sonic flight which Comanches,
Cessnas and Cherokees, etc. have little to worry about. For
all of that did the swept rudder/fin on the Comanche, any
of the Cessnas or, more to the point, the Cherokee enable
any of them to fly faster? No, knot at all.
From a strictly aerodynamic perspective a sweptback rudder, its uppermost portion anyway, is located
slightly farther rearward than a straight rudder mounted
in the same position. This slightly moves the rudder’s CP
(centre of pressure) rearward and increases the uppermost part of the rudder’s moment arm which therefore
ought to increase its eectiveness to a small degree.
Others have postulated that the swept back fin/rudder is actually less eective and that it somewhat compromises directional stability and spin prevention. It
may be, however, that with regard to this it was an earlier straight- tailed 172 which was compared to a 1963 or
later swept-tail Cessna 172/Skyhawk with “Omni-Vision”
. If so, it is more likely that the cause of any perceived reduced rudder/fin ineectiveness, etc. was not necessarily the swept vertical surface but was actually the later
-
Piper PA-28-160 Cruiser showing
swept-back n and rudder 1967 Mooney M-20C Ranger 1962 Mooney M-20C Ranger
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aircra’s cut - down rear fuselage which provides for the
“Omni-Vision” rear cabin window, and that the reduced
side area of the fuselage behind the C.G. is the real culprit for any directional stability or spin issues.
Also, if the aeroplane is banked a displaced sweptback rudder will tend to couple with both the aircra’s
pitch axis (as usual) and also positively to greater than
usual degree with the aircra’s roll axis. Accordingly, a
swept forward displaced rudder will couple negatively
with the aircra’s roll axis.
What a swept rudder/fin actually does as compared to a
straight one with regard to relatively low- speed GA aircra
might be able to be measured in a wind tunnel or by a very
sensitive set of in-flight instruments, but this writer is not
aware that any such study has been conducted. Having of
ten flown versions of the same aircra (C-172 and 182) with
both straight and swept tails this writer has not noticed any
appreciable dierence in the performance and handling
thereof that might be due solely to the rudder/fin configu
ration. Taking everything we know into consideration it
seems that a reasonable conclusion regarding this matter
is that the swept back rudder/fin on GA aeroplanes is noth
ing more than an eye- catching marketing tool which is, after all, still a legitimate reason for its existence.
One last, possibly definitive note on this subject; Al
Mooney ostensibly designed the Piper Comanche with
its swept back rudder/fin. However, all of his designs for
Mooney Aircra incorporate rudder/fins that famously
sweep forward.
COMFORT AND ECONOMY
Comfort: One of the important issues that Piper’s design
team had to consider was the creation of a new aeroplane that would cost far less to build and thereby be
able to be sold at a much lower price than the Comanche.
While the team considered that designing an aeroplane
that was less costly to build would not be so arduous a
task (Weick and Thorp had been designing inexpensive to
build aeroplanes for decades), simultaneously providing
the new aeroplane with a cabin as or more comfortable
than anything in its class was a bit more daunting.
Cabin size and particularly cabin width is a tricky
thing to consider when designing a small aeroplane. Every extra inch expands the frontal area and, accordingly,
increases parasite and form drag, resulting in a higher
Cd and reducing performance for available power
across a broad spectrum.
Piper’s target competition, the Cessna 172’s cabin is
a fairly cosy 39 ½” wide. This is a relatively tight fit for
full - sized adults, 1/2” narrower than Piper’s previous
single- engine flagship, the Tri-Pacer, with its snug 40”
cabin width. In years past this writer flew many pleasant
hours in Tri-Pacers and somehow does not remember
that it was such a tight fit; but then that was many years
ago and this writer was then, let’s say, a bit smaller.
The planned cabin width of the new aeroplane was
at first to be a generous 44”, the same width as their then
single-engine flagship, the Comanche. However, Piper
felt that its new, more economical aeroplane ought not
compete so closely with its flagship aeroplane and it
wanted to reserve to the Comanche just a bit more cabin comfort than its less expensive brother. Accordingly,
the Cherokee, as the new aeroplane was finally named,
would have a 40 1/2” wide cabin, still an inch wider than
its closest competitor, the Cessna 172.
Another way that the Cherokee was designed to
increase cabin space while keeping construction cost
low was by utilizing the fuselage’s external belly skin,
strengthened with external stiening members, as the
cabin floor. This was inexpensive, light and required
fewer parts than did many contemporary designs. This
ingenious design treatment added cabin headroom
without the need to expand the outer dimensions of the
fuselage and thus increase parasite and form drag.
In addition to cabin size, Piper wanted their new
aeroplane to be quieter than its competition. The Cessna 172’s design approach is towards a definite lightness
of structure which results in a less noise- insulated cabin
due to the 172 having a rather thin firewall, doors, windows and other structural members resulting in a fairly
noisy cabin. Well-understanding Cessna’s design preferences, Piper looked to find a way to gain an advantage
by reducing the Cherokee’s cabin noise. This was done
by generally using thicker, sturdier structural members
particularly in and around the cabin and by placing the
engine as far forward as possible without jeopardizing good pitch control balance. This kept the engine’s
twin exhaust stacks, which are located near the front of
the engine, as far away from the cabin as possible. The
upshot is that the Cherokee has a very quiet cabin, not
usually requiring headphones for its occupants to converse in flight.
Economy: One of the ways that an aeroplane may be
produced more economically is for it to be designed with
as few parts as possible. The Cherokee was, accordingly,
designed to be extremely simple to construct with much
redundancy (i.e., all wing ribs were the same size, identical le and right parts where possible, etc.) as well as having very few complex curves requiring more costly and
labour intensive aluminium panel construction, shaping
and fitting. Accordingly, the new Cherokee was designed
with less than ½ as many parts as the more complex and
more expensive to build Comanche. A demonstrative example of this is that the Cherokee uses 1,785 rivets while
the Comanche uses more than twice that amount at
3,714. (Yes, I did count them all myself — not)
Another example of intentional simplification is that
the Cherokee’s ailerons require ten parts to construct
while the Comanche’s ailerons require thirty-six parts.
Additionally, and in keeping with his long-held and successful design practices, John Thorp designed all of the
Cherokee’s tail surfaces, flaps and ailerons to be as lightweight, simple and thereby less expensive to construct
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AN AEROPLANE FOR THE REST OF US
Corrugated skin on 30’s W.W. II era transport Junkers
JU-52 “Iron Annie”
Piper Cherokee
rudder showing
corrugated skin
Cherokee
unpainted
stabilator
showing
corrugated skin
as possible by requiring no internal ribs or heavy internal
structures within them. This particular weight- saving
practice is also found in the designs of many GA aircra.
Stiness of the Cherokee’s tail surfaces, flaps and ailerons is provided by beaded (corrugated) surface skins,
similar to that which was pioneered by and appeared on
Junkers aircra of the W. W. I era and later and which was
also largely utilised by John Thorp on many of the aircra
which he had previously designed in order to save weight
and to foster simplicity of construction. Piper was familiar with this construction technique as its PA-18 Super
Cub’s metal ailerons and flaps are covered with the same
kind of corrugated skin for stiness.
Another parts- count, weight and cost saving was
the Cherokee’s incorporation of “wet wing” or “integral”
fuel tanks formed by the wing’s leading edge structure
rather than the usual practice of installing separate fuel
cells within each wing. The wet-wing fuel tank maximises the quantity of fuel that may be carried on board
while requiring the least amount of wing structure to
contain it. Of course, the fuel- carrying part of the wing
must be designed and built with great integrity so that
all panels, rivets, connectors, etc are leak-proof and will
not even slightly separate under flight loads. Possibly
the earliest application of wet wing fuel tanks appeared
in Fred Weick’s remarkably prescient 1936 Ercoupe.
Another cost and weight saving measure applied to
the Cherokee was the innovative and extensive use of
inexpensive- to- produce fibreglass parts in place of aluminium for the wing and stabilator tips as well as for the
cowling. The use of fibreglass in these areas was also
potentially cost-eective for the Cherokee’s owner in
the event that these parts were ever damaged and had
to be replaced as the vulnerable wing and tail tips and
cowling are oen the common victims of “hangar rash”
and other inadvertent abuse.
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A2ASIMULATIONS
Cherokee with
Cherokee
unpainted
fuselage and
n showing
corrugated skin
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“wet wing” fuel
tank removed
Cherokee breglass
wing tips
WHEELS AND FLAPS
The Cherokee’s undercarriage is tri-cycle with a fully
steerable nosewheel, independently sprung but directly connected to the rudder control system which was
the same arrangement as was used in the Tri-pacer and
Comanche. In early Cherokees the main undercarriage
brakes were not operated by toe pedals but by a single,
centrally located “Johnson Bar” brake handle, also as
in the Tri-Pacer. This system somewhat limited tight,
precise ground steering and was not a popular feature.
While trying to save on manufacturing costs by using
previously designed, well-proved and readily available
parts and components from the Tri-Pacer, the fact was
that some of these were long overdue for an upgrade.
The Cessna 172 had toe- operated brakes on both sets
of rudder pedals from the get go which was a notable
feature discrepancy. Within a few years and aer many
complaints Piper relented and installed dual individual
main toe brakes for both sets of rudder pedals in the
Cherokee, operated by depressing the tops of the rudder pedals individually to turn or both together to slow
or stop.
Simple, easy to manufacture and to maintain
straight oleo (compressed nitrogen and hydraulic fluid)
struts are used throughout. The Cherokee has a distinct
advantage over the Cessna 172 in that, as a low-wing
design, its main undercarriage is attached directly to
the main wing spar providing maximum strength and
stability. The Cherokee’s 10’ wide main undercarriage
tread provides excellent and stable ground handling
under all conditions while the Cessna 172’s main undercarriage which is a pair of steel struts attached to the
fuselage, has a tread of a little more than 8’ 4”.
Fred Weick had done a number of advanced undercarriage tests when he was designing the Ercoupe which
showed that in a tri-cycle undercarriage the nosewheel
was oen under the greatest load. He also determined
that for operations on grass and on other so fields that
all three tires ought to be the same size. Accordingly,
the Cherokee has 6.00 x 6 tires on all three wheels. With
regard to the Cherokee’s undercarriage, Piper evidently
got it right as pilots have universally praised the Cherokee’s easy, dependable ground handling.
With regard to the Cherokees’ flaps, they are narrow
in chord and have a simple, inexpensive up/down linkage with an over-centre lock when up. They are manually controlled by a bar with a release button at its top
located between the front seats. The flaps have four
positions: up, 10º, 25º and 40º down. Although the rectangular wing’s flaps are more eective than those of the
semi-taper wing’s, with regard to flaps the palm must
go to the Cessna 172. It has larger and more eective
broad-chord flaps, linked so that as they lower they also
move rearward out of the wing, increasing their overall
area.
Most (me, too) would call the C-172’s flaps “Fowler
flaps” because of their rearward-moving, area-increas-
Simple ap - Piper
and most GA aircraft
Slotted ap –
Cessna and some
other GA aircraft
Split ap - Many
1930’s and W.W.
II era aircraft
Fowler ap – mostly
airliners and
heavy aircraft
ing feature; but in all of the FAA approved oicial C-172
POHs, Cessna calls them “Slotted Flaps” and therefore
that is the only correct answer if you ever are tested on
the subject by your instructor or the FAA (you’re welcome). The Cessna’s flaps have slots (openings along
the hinge line to allow oncoming air to pass through
when the flaps are lowered) which prevent their large
size from creating uncomfortable induced rumble, vibration and turbulence when deployed. As it is there
is still a distinct audible and visceral rumble when you
lower the flaps in a 172, but most pilots don’t mind this
much as the flaps are eective and do their job well.
In any event, don’t get too exited by the Cherokee’s
40º down flap position. The Cherokee’s flaps do what
flaps are intended to do, but even when fully lowered
they perform to a lesser extent than those of the 172. In
1964 when the Cherokee had been out only two years
Cessna “upgraded” the 172’s manual flaps to an electric
operating system. Whether or not this was intended as
a one-up on the Cherokee, this writer does not see this
as a positive advance as electrically operated flaps are
not really necessary in an aeroplane as light as the 172.
In aeroplanes of this class, this writer prefers the direct control granted to the pilot with the manual flap
control. For instance, with a manual flap control the
pilot can instantly raise the flaps and thereby dump li
upon touchdown to set the tires firmly against the runway for braking if and when such is desired. A manual
flap system allows them to be extended or retracted
at any rate the pilot wishes while the electric system
extends and retracts the flaps at a fairly slow, pre-set,
non-adjustable rate. Also, should the aeroplane’s electrical system fail, manually operated flaps would be unaected.
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AN AEROPLANE FOR THE REST OF US
VICTORY — EVOLUTION AND REFINEMENT
Once Pug’s, Weick’s, Thorp’s and Bergey’s design was
named, solidified and its exact details determined,
the Cherokee was assigned Piper Aviation production
model number PA-28 and a prototype for flight testing was built. This first flying Cherokee was essentially
what would become the PA-28-160 and was powered
by the highly reliable 160 hp Lycoming O-320-B2B engine (later PA-28-160’s would also use the O-320-D2A).
Thomas Hener, chief test pilot for Piper, had the honour of being the first Cherokee pilot to fly the first of over
33,000 Cherokees built on either 10 or 14 January 1960
depending upon what you may read.
The new Piper flew, as it is said, “Right o the drawing board” and everything that its brilliant design team
had intended and built in to it was realised. The first
production Cherokee, the 160 hp PA-28-160 was type
certified on 31 October 1960 and went into production
in January 1961. Aer a short period of pre-release
promotion it was released for sale to the public, and
soon thereaer it was joined by the slightly less expensive 150 hp PA-28-150. Both of these aeroplanes were
instant hits with the aviation public. Flight schools,
clubs and private owners all throughout the Unites
States placed orders and Piper sold 286 Cherokees in
its debut year. Gratified (but not, I dare say, entirely
surprised) with this a great success, plans which had
been made to expand the Cherokee family if all went
well went into immediate action.
It is said that when one door shuts, another one
opens, and vice versa. This was no less true at Piper Aviation. Simultaneously with the introduction of the Cherokee, the parts inventory, tooling, jigs and part manufacturing stations, all of which had been used to build
the once revolutionary PA-22 Tri-Pacer and its two- seat
version, the Colt, were disassembled and disposed of.
With a sigh and perhaps a tear or two, these aeroplanes
passed into aviation lore.
For one year the 150 and 160 hp Cherokees represented the entire line. However, Piper’s well-laid plans
to expand it to include Cherokees of greater power were
busily being implemented. On 3 August 1962 the PA-28180 powered by the versatile and by now ubiquitous
workhorse of GA, the 180 hp Lycoming O-360 A2A (yes)
was type certified and began to roll out of the new Piper
factory at Vero Beach, Florida in early 1963. With a useful load of 1,170 lbs., this was the first Cherokee in which
four substantially sized adults could fly in addition to
full tanks (50 US gallons).
By the end of 1963, Piper could quite rightly claim
victory and justifiably feel that its bourne had indeed
gloriously arrived and had produced most excellent
fruit. The Cherokee PA-28-160 equalled or bested the
Cessna 172C in virtually every area of performance.
Additionally, and surely much to Cessna’s discontent,
when Piper installed the 180 hp 0-360 Lycoming in the
Cherokee airframe creating the Cherokee PA-28-180 for
which Cessna had no equivalent model, the additional
20 hp gave it even better performance over the 172. (Figures below supplied by Piper and Cessna*)
*Just a note about manufacturer’s published performance figures: Of course, there is always the temptation
to, let’s say out of politeness, “exaggerate” these numbers. However, the FAA does not permit this practice to
go too far as pilots must be able to rely on accurate published performance numbers so that they may, among
other things, safely plan cross-country flights. All oicial
aircra POHs must be certified as containing information which is based upon real-world testing and which
is as accurate as possible. To get around this, manufacturers have been known to publish performance numbers, particularly in advertisements, that were obtained
when the aeroplane was loaded at less (sometimes
much less) than MGW.
Versatility is one of the many charms of the Cherokee’s basic airframe and it has been eortlessly adapted
28
Service ceiling (100 fpm climb) 15,000’ 16,000’ 14,550’
Note: The Cherokee 160 and 180’s performance reports were made while being tested at MGW. We cannot confirm
that Cessna 172 was similarly tested at its MGW. Also, note that the Cherokee 180’s excellent performance was
measured while it was carrying 180 lbs. more useful load than either the Cherokee 160 or the Cessna 172.
A2ASIMULATIONS
Cherokee 160 Cherokee 180 Cessna 172C
Max. speed at sea level 120 kts (138 mph) 132 kts (151.8 mph) 120 kts (138 mph)
Cruise- 75% power at 7,000’ 115 kts (132.25 mph) 124 kts (142.6 mph) 114 kts (131 mph)
Rate of Climb @ gross
weight - sea level
Stall – flaps down power o 48 kts (55.2 mph) 50 kts (57.5 mph) 45 kts (51.75 mph)
Takeo: ground roll 740’ 720’ 825’
over 50’ 1,700’ 1,620’ 1,830’
Landing: ground roll 550’ 600’ 690’
over 50’ 890’ 1,150’ 1,140’
Useful load 990 lbs. 1,170 lbs. 990 lbs.
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700 fpm 750 fpm 700 fpm
Lycoming 0-320 B2B
1963 Piper PA-28-180
to engines of varying power, from 150 to 300 horsepower, with little airframe modification being required.
Piper Aviation and its brilliant engineering team
had accomplished what it had set out to do, to provide
a real choice in the GA market between the new Piper
aeroplane and the Cessna 172. As William T. Piper, with
his hand ever firmly on the aviation public’s pulse had
predicted it would be, the introduction of the Cherokee
was greeted most enthusiastically, which enthusiasm
has not and shows no sign of waning.
THE CHOICE
Fitting neatly between the Cessna 172 and 182, when
it was introduced in 1963 the Piper Cherokee 180 filled
a niche that had long wanted filling. Accordingly, it became and remains on
In both its latest incarnation, the PA-28-181 Archer TX
and LX, and in the many PA-28-161 Warriors which have
had a 180 hp Lycoming engine replacement,* the combination of the Cherokee airframe and a 180 hp engine truly is the magic touch, the Goldilocks aeroplane indeed.
The first dierence that one notices regarding the
Cherokee vs. the 172, putting all of the performance
* Just a word about Warrior engine upgrades, it is
this writer’s understanding that the popular Sykes STC
(Arch-Warrior SA2946SO) and the few others that exist
which permit and regulate the installation of a 180 hp
Lycoming 0-360, and which also require the installation
of a larger propeller on the Warrior airframe, curiously
do not include a concurrent increase in he Warrior’s
MGW (maximum gross weight), making the choice to
do this expensive, PITA upgrade somewhat dubious.
Better to just sell the Warrior and buy a good Archer.
*
e of GA’s most popular aeroplanes.
numbers aside for a moment, is obvious — the wing.
172s have a high wing, Cherokee’s, a low one. As mentioned, the pilot and passengers of a high wing aeroplane have and almost entirely unobstructed downward view which is excellent for sightseeing and which
facilitates navigational orientation. The problem with
most high - wing aeroplanes (excepting those few highwing designs where the pilot sits well-forward of the
wing) is that the wing obstructs visibility whilst in a
turn. This may not be much of a problem enroute when
few turns are made and the sky is mostly clear of traffic; however, when in the pattern at a busy airport, the
problem becomes clear.
In a high-wing aeroplane, even though a pilot may
be properly diligent in checking that the sky is clear prior to making a turn, once in the turn he or she is blind
to all that may be to the inside of the turn. Additionally,
for the duration of the turn, short of liing the wing and
stopping the turn to re-clear the sky, the pilot has no
way to know if another aeroplane has entered that area.
A low- wing aeroplane has no such problem in the
pattern. The inside- turn wing politely gets right out of
the way in the direction of the turn, granting the pilot
an unobstructed view of where he or she is flying. As
to downward visibility, the low wing does not obstruct
the view nearly as much a one might think. In all of the
many, many hours that this writer has spent flying low
wing aeroplanes, there has never been an instance that
comes to mind when a want of downward visibility was
an issue.
Another dierence between the high-wing 172 and
the low-wing Cherokee is ground eect during takeo
and landing. Ground Eect is that property of aerodynamics which causes a “bubble” of liing air to form under a wing when it is flying within approximately at ½ of
its span from an incompressible, solid surface which, of
course, includes water. Because of its proximity to the
ground a low-wing aeroplane will usually create stronger ground eect than a high-wing aeroplane, and when
descending to the runway, it will be felt sooner as well.
During takeo as well, all else being equal, the pilot of
a low-wing aeroplane will most oen feel the onset of
li more readily than the pilot of a high wing aeroplane.
Of course, the pilot of the low wing (or any) aeroplane
must be cautious and not try to climb out too soon on
the ground eect bubble, but must wait until the aeroplane has accelerated to its proper airspeed before
climbing further.
On takeo, at neutral trim the Cherokee will not (unless somewhat a loaded) li o by itself as will the
Cessna 172. Some airmative, but gentle a yoke at the
appropriate airspeed, approximately 50-55 knots (57.5
63.25 mph) depending upon gross weight, will be necessary to rotate and li o. This is because the Cherokee
normally sits at a level or slightly negative Alpha during
the initial takeo run. Also, and for the same reason, in
neutral wind conditions, minimum right rudder input to
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AN AEROPLANE FOR THE REST OF US
Fuelling a Piper
Cherokee
Checking fuel
level in Cessna
172 left tank
Piper Cherokee
with left cowling
open for engine
inspection
during walkaround (both
sides open
similarly)
Some Piper
Cherokees offer
large doors on
both sides of the
cowling while
others offer
the entire top
cowling to be
easily removed.
oset P-factor is required during the takeo run.
The Cherokee’s roll rate, particularly with a rectangular wing, is faster than that of most other GA aeroplanes. At the commencement of a turn the rectangular wing produces little or no adverse yaw, less in any
event than does the semi-tapered Cherokee wing and
definitely less than does a Cessna 172. Overall, the Hershey Bar wing Cherokee feels more maneouverable and
sprightly than the 172, and very like a sport aeroplane.
When landing a Cherokee the onset of ground eect
can be clearly felt and may enable very gentle and satisfying touchdowns. While a gentle landing may certainly
also be made in a Cessna 172, in this regard the Cherokee is more consistent and seems to require less finesse.
When the wind blows strong the Cherokee has an
obvious advantage over the Cessna 172 whilst on the
ground. As mentioned, the Cherokee’s vertical centre of
gravity (C. G. v) is much closer to the ground than that of
the Cessna 172. Also, the Cessna’s wing sitting up above
is more likely to catch the wind than the Cherokee’s low
wing. Accordingly, the Cherokee naturally sits on the
ground more firmly and stably and is less prone to be
tipped over by a mighty blast than is the 172. Additionally and most significantly, as mentioned, the 172’s wide
undercarriage is only 83% as wide as the Cherokee’s undercarriage which also handicaps it when attempting
tight turns whist taxiing.
Not only does the Cherokee’s wider undercarriage
permit easier and tighter turns, it is far more stable than
the 172 in a fast turn. Additionally, the high-wing Cessna
172 is more vulnerable to cross- winds on takeo than is
the Cherokee. This writer recalls being almost tipped up
onto the downwind wheel in a Cessna 172, when a sudden powerful cross- wind gust struck the aeroplane during takeo. This writer recalls that the Cherokee in similar winds just tends to shrug o such a gust and takes o
with little problem. Our good friend Darryl knows something about dangerous cross winds in a Cessna 172.
The Cherokee’s stall and departed flight characteristics are far gentler than that of the Cessna 172. As mentioned, the Cherokee does not break much if at all at
the stall while the 172 has a most definite and vigorous
break. While neither the Cherokee nor the Cessna 172
may be legally spun whilst at normal category, at any
weight the Cessna 172 is far more likely to inadvertently
spin out of even a mildly a cross- controlled stall than is
a Cherokee.
More practically, because of its low wing it is much
easier to look into and fill the Cherokee’s fuel tanks than
the Cessna 172’s tanks which require a somewhat awkward and tenuous step up and climb to check the fuel
quantity. On the other hand, it is far more awkward to
stoop down low under the Cherokee’s wing to check
and to drain the wing tank’s sumps prior to takeo than
to do the same under the high wing of a Cessna 172.
Also, where the Cherokee allows a complete visual inspection of the entire engine and its components during
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