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The Anatomy of the Airplane
The Anatomy of the Airplane
Darrol Stinton
Past Senior Visiting Fellow, Loughborough University of Technology, Leicestershire, UK
Second Edition
Co-published by: American Institute of Aeronautics and Astronautics, Inc.
1801 Alexander Bell Drive, Reston, VA 20191 and Blackwell Science Ltd, Osney Mead, Oxford, 0X2 OEL, UK
American Institute of Aeronautics and Astronautics, Inc. 1801 Alexander Bell Drive, Reston, VA 20191
THE AUTHOR
Darrol Stinton MBE, PhD, CEng, FRAeS, FRINA, MIMechE, RAF(Retd) was born in New Zealand and grew up
in England. He is a qualified test pilot and aeronautical engineer who worked in the design offices of the
Blackburn and De Havilland aircraft companies before joining the RAF. His test flying spanned 35 years and
more than 340 types of aircraft, first as an experimental test pilot at Farnborough; then 20 years as
airworthiness certification test pilot for the UK Civil Aviation Authority on light airplanes and seaplanes, before
turning freelance.
He has lectured regularly at the Empire Test Pilots’ School, Loughborough University, the Royal Aeronautical
Society (of which he is a Past Vice President), and the Royal Institution of Naval Architects. His company
specializes in cross-fertilization between aircraft and marine craft design and operation.
ALSO AVAILABLE
The Design of the Airplane Darrol Stinton 0-632-01 877-1
Flying Qualities and Flight Testing of the Airplane DarrolStinton 1-56347-274-0
‘If anyone tries to tell you something about an aeroplane which is so damn complicated that you can’t
understand it you can take it from me it’s all balls.’
R. J. Mitchell (1895—1937)
Designer of the Supermarine Spitfire
Preface to the First Edition
One should never have too much reverence for ideas, no matter whose they are. Ideas are meant to be kicked
around, stood upon their heads, and looked at backwards in mirrors. It is only in this way that they can grow up
in the way that they should, without excessive self-importance. The ideas of one man are the food for thought
of another. Perhaps Oliver Wendell Holmes had this in mind when he said something to the effect that: ‘A
man's mind stretched by a new idea can never go back to its original dimensions’. And that is the reason for
this book.
The Anatomy of the Aeroplane was started in 1960 as a set of supplementary notes to the author’s
annual lectures on Aero-Structures given at the Empire Test Pilots’ School, at Farnborough in Hampshire. The
lectures were intended to give embryo test pilots an insight into the reasons for aircraft not being shaped in
ways that fitted the often more elegant theories. In so doing the inherent capabilities and limitations of an
aeroplane became more apparent. The capabilities and limitations were seen to be functions of specific
requirements: those formalized statements of human needs that cause aircraft to be made as useful and as
safe as possible within the ‘state-of-the-art’ at a given time. The seeming dichotomy of the two worlds of theory
and practice — usually more apparent to the practical man than the academician — is resolved by looking at
the development of an aircraft as a response to a set of requirements.
The aim of the book is to show students of aeronautics how requirements affect the application of
theories, causing aeroplanes to be twisted, bent, cambered and kinked, to end up without the flowing
perfection of their original, idealized, forms. It is aimed in particular at students in developing countries who,
the author has found, are bursting with the desire to learn and assert their own ideas, but who cannot yet gain
the practice they require. To this end a number of specialized subjects are introduced and shown in relation to
the end product of the finished aeroplane. In this way the student will be able to specialize later with some idea
of where his own subject fits into the whole.
The treatment of the subject is such that the reader should be able to reason for himself why every
salient feature of any aeroplane is shaped as it is. In doing this the book will probably make some enemies
among those who cherish a professional mystique behind which to hide. That does not matter, for the book will
have served its purpose if only one student gets a better feel for his subject than he might otherwise have had.
The word aeroplane is used throughout in preference to airplane, or the meaningless plane, for two
reasons. The first is that it is a scholarly word applied to a particular order of a class of aircraft. The second is
that it derives from two Greek words meaning, literally, airwandering. That is excellent, for the word touches in
part upon the spirit of aeronautics and the impulse to wander in the air that made men want to fly in the first
place. The Concise Oxford Dictionary describes an aeroplane as a ‘mechanically-driven heavier-than-air
flying-machine’. Taking the definition further: the Glossary of Aeronautical Terms of the British Standards
Institution defines an aeroplane as ‘a power-driven heavier-than-air aircraft with supporting surfaces fixed for
flight’. The name includes landplanes, seaplanes (float-seaplanes and flying boats), and amphibians
(float-amphibians and boat-amphibians).
Unfortunately, precise definitions of this kind miss out the most beautiful of all winged machines, that
comes nearer to wandering-in-the-air than any other: the sailplane. For the purposes of this book the definition
will treat an aeroplane as a heavier-than-air flying-machine with fixed wings (i.e. wings that do not beat the air
as a means of propulsion, although they may be moved fore and aft in flight) while avoiding any need to
specify the means of propulsion. There is no great inconsistency in doing so, for the first aeroplanes grew from
kites and gliders, and the sailplane is a highly refined glider.
The evolution of powered aeroplanes is such that they outstrip the definition. Since sustained flight
became a possibility, little more than half a century ago, the performance of the aeroplane has increased more
than one hundred fold. Cruising speeds and heights, range and endurance, carrying capacity and weight (and
complication) have all increased. In order to fly fast smaller wings are used to achieve optimum efficiency, but
smaller wings bearing heavier loads require more space for take-off and landing, and space is at a premium.
This has led, under pressure of military necessity, to the development of short and vertical take-off, STOL and
VTOL aeroplanes. We may not like to recognize it, but most significant advances are brought about through
military necessity. And now there are dreams of aeroplanes employing powered lift throughout the whole
envelope of flight, for cruising as well as for take-off and landing.
The scope of the book is broad. Essentially it is a physical textbook, written in five parts, with a number
of additional appendices. These have been added in order to focus attention upon some specific areas of
operation: supersonic transports, aero-buses, strike and reconnaissance aeroplanes of various kinds. As far
as possible early project aeroplanes have been used as illustrations, for these show most clearly the first
thoughts of designers, with little adulteration. Many of the aircraft shown are really in the form of feasibility
studies — the stage before becoming a project, in which a particular way of doing a job is investigated to see if
it is worth continuing with as a project.
Mathematical statements are simple, amounting to little more than 1 + 1 = 2, or 3 = 6/2, and using
symbols to say so. Although British symbols are used these are defined, and repeated where relevant, so that
the foreign reader should have no difficulty in converting them to the standard symbols of his own country.
Equations are, for the most part, unit-less —although the ft-lb-sec system is used where stated. The reason for
avoiding units is that the ideas count more than quantitative results, which belong properly in a handbook of
aircraft design. Some basic calculus symbols are used, but it is only necessary to know what is meant by Δ x
and dx when they appear.
A significant departure from standard works on aerodynamics is that to explain the nature of
aerodynamic phenomena and forces aeroplanes are considered in motion through the air, instead of the usual
reverse. There is plenty of time for the reader to come round to the conservative point of view, of visualizing an
aircraft somehow motionless in space, with air flowing past it. This view has been deliberately rejected, not
only because aeroplanes do not fly that way, but because certain concepts — like circulation, and its effect
upon aerodynamic forces — are more readily understandable if one goes straight to the point of trying to see
what really happens to the air. Furthermore, stability and control (neither of which are easily mastered if one is
not happy with textbook mathematics) become simpler when seen as the pilot sees them: as properties of a
machine that, under his hands, seems to be alive as it moves through apparently living air.
The author is indebted to a large number of people who, directly and indirectly, have either helped by
providing material, or have helped with the play of ideas thrown up as the book was written. Among these are
three test pilots: Wing Commander N. F. Harrison DSO, AFC, RAF, Don Wright, and Squadron Leader G. M.
Morrison, RAF. Others are Ernest Stott, the artist: Squadron Leader J. H. Maguire, MBE, RAF, Charles
Gibbs-Smith (who provided the copy of the Sir George Cayley medallion), Derek Dempster, Alastair Pugh, Dr
M. H. L. Waters, W. T. Gunston, W. W. Coles, and D. Howe of the College of Aeronautics. Thanks are also
due to the Blackburn and De Havilland Divisions of Hawker Siddeley Aviation Ltd, Bristol Siddeley Engines
Ltd, the British Aircraft Corporation, Short Brothers and Harland Ltd, The Royal Aeronautical Society, Air et
Cosmos, Flight International, Interavia, Shell Aviation News, and the Air Registration Board.
It should be noted that the views expressed are those of the author. The book does not reflect any
policy or opinion of either Her Majesty’s Government or the Royal Air Force.
Darrol Stinton
Mattingley, 1966
Preface to the Second Edition
Since 1966, when this book — which became known widely as The Anatomy — was first published,
developments and changes in the world of aviation have been vast. Most significantly the Cold War has
ended, empires have crumbled, the shapes and centers of gravity of states have shifted. Former large and
important aircraft companies, synonymous with past progress and national survival, have merged with or been
devoured by newly formed international and other conglomerates.
Famous family names have disappeared. Political and industrial change has brought new possibilities,
the effects of which, both favorable and adverse, can only be guessed. In the UK the Royal Aircraft
Establishment at Farnborough, which served both military and civil contractors, is no more. It has been
replaced by the Defence Evaluation Research Agency (DERA).
The once supreme pair of airworthiness authorities — in 1966 the Air Registration Board (ARB) in the
UK (which became the Civil Aviation Authority (CAA) early in the 1970s) and the Federal Aviation
Administration (FAA) in the USA — have been joined by the complex European Joint Aviation Authorities
(JAA), of which the CAA is now part. Authorities elsewhere, in Canada and Australia for example, take national
initiatives with consequences on a world scale of utmost importance for operators, manufacturers of engines
and airframes, which cannot be ignored by the JAA, CAA and the FAA.
Among outstanding civil successes are three of many. The first has been that of the Anglo— French
Concorde which in the first edition was only an elegant shape. Now, just as elegant as any current project, and
in spite of back-biting and lightweight criticism, it has been in safe service for more than 20 years, with no end
to its operational life in sight as this is written. Second is that men and women have flown into Earth orbit,
worked in space, and returned in the Shuttle — a powered aeroplane outbound and a dead-stick glider
inbound. Third is the round-the-world non-stop flight of Burt Rutan’s canard and twin-boom Voyager, cruising
on its rear engine and crewed by co-builders, Dick Rutan and Jeana Yeager. Other developments include
successful man-powered flight.
That is not the end of it, because there is now the powerful microlight aeroplane movement; and the
parapente (French — a para-glider inflated wing with a lightweight motor); and massive homebuilt aircraft
movement which experiments with man-made materials, and new types. Within that movement people like
Burt Rutan and Jim Bede have been a moving force. The air is now within reach of the individual as never
before.
Fresh concepts abound and there are new terms to describe applications of older physics in the main
The historic, classic and vintage aircraft movements thrive in Europe, America and Australasia, with
air-shows coming second only to football as the most popular spectator sport.
Civil aeroplanes have grown in size with the trend towards fewer and larger turbofan engines, even for
long-haul operations, instead of three or four smaller turbojets or turbofans. The turboprop — a tiny jewel of a
gas-generating jet engine turning a propeller — is now used more commonly where the piston propeller engine
once reigned supreme. Turboprops are super-reliable high cost units compared with piston-propeller engines.
Reliability and high cost force operators and manufacturers to argue seriously the case for public transport
certification by the airworthiness authorities of relatively large aircraft containing nine, ten, or more people,
hauled behind a single turboprop. There are arguments on both sides, but it looks like the authorities will yield
to urging from the market place.
On the military scene, while the heavy V-bomber conversion, together with converted airliners, remains
relevant as a tanker for in-flight refueling, the age of the 'smart’, the ‘fire-and-forget’ projectile, bomb and mine
is with us. One relatively small bomb, placed with pinpoint accuracy by laser target-marking, delivered by a
two-seat aeroplane no larger than a jetfighter, can today do at least as much to neutralize an enemy as 1000
bombers, propelled by 4000 piston-propeller engines and manned by 10000 aircrew in 1944. Couple this with
in-flight refueling over continental ranges and a small aeroplane, once regarded as tactical, can deliver a
strategic punch.
Powered (jet) lift, still in operational infancy 30 years ago, had revitalized the aircraft carrier. First came
vertical take-off and landing (VTOL). Now, using conventional runways, or modified flight decks on warships
no larger than light cruisers or large destroyers of World War II, one may create agile, stealthy aeroplanes with
thrust vectoring, which further combine heavier load-carrying with short take-off and vertical landing (STOVL).
The technology of flying controls has changed everything. We use the term 'high-order’ (advanced)
flying controls, meaning those which employ fly-by-wire, or fly-by-light, using fiber optics and 'active controls’
(constantly moving) to replace stability. Such controls rely upon one or more computers, interposed between
the pilot and the aircraft. They are expensive, special-purpose systems, not found on light or other subsonic
aircraft.
text, and in the appendices: stealth, radar-absorbent materials and uses of shape; small, regional/commuter
and business aeroplanes, with discussion of handling and commercial disadvantages; utility and freight (cargo)
carriers, and arguments for single vs twin engine, coupled engines and contra-props; post-aero-bus
developments; design for emergency evacuation; trends with long-haul aeroplanes; SST research for the 21st
Century, and current research with slewed (yawed) wings; military design for agility and stealth; the fate of the
TSR.2 and a review of its lost potential; aircraft designed for wide speed-range, VSTOL and STOVL; ram-wing
and ekranoplan (Russian), designed to utilize ground effect, and their commercial possibilities; AeroShip, a
heavy-lift delta wing for disaster relief, with an on-board field hospital; nuclear propulsion and uses of solar
energy to provide unlimited range.
Out of these other subjects arise: use of the air for an attempt upon the water-speed record, ablation of
surfaces and cavitation; supercritical aerofoil sections; the electromagnetic spectrum, ionization,
radio-interference and blackout; comparison between single, canard, tandem and three aerofoil-surface
configurations; the combination of aerodynamic and aerostatic lift within one airframe; solar energy, nuclear
propulsion, and use of liquid hydrogen (LH 2 ) as a fuel in place of hydrocarbons; turbofan and propfan engines;
glass cockpits; powered lift and thrust-vectoring; elimination of tail-surfaces, replacing them with
thrust-vectoring and artificial control and stability; super-maneuverability; structures using carbon-fiber and
glass-reinforced plastics.
Appendices which included design projects intended for criticism were praised in reviews of the first
edition. In this second edition the appendices have been updated and extended. As before, there is meat
enough to foster and stimulate criticism, while deliberately hanging in the air is the unstated question: ‘OK,
then show us how you would have done it better?’
As the French-born Octave Chanute, later to be a valuable advisor to the Wright Brothers, said in 1870:
‘I have always thought that aviation would never be the invention of a single person. I never patented anything
and I published all my designs so that they could be useful to others.’
Chanute’s philosophy is important today, when engineers and technicians, insulated from the real
world of machinery which often goes wrong, fiddle around on computers with images which look convincing,
but which just as often are inadequate when built and flown. This book encourages you to learn from the work
of others, and to be critical above all.
The author has never tested an aeroplane that was not flawed, sometimes severely. It would be
tempting to use existing aircraft as illustrations, for criticism or praise, but the first would be unethical without
knowledge of what was in the designer’s mind at the time. Praise would be mere advertising, and of little value
to students of design. Instead, as many examples as possible have been included which are projects with
which the author has been closely involved, in project design, as an aero-marine consultant, or generalized in
35 years experience as a qualified test pilot. Their purpose is to be pulled apart to reveal the good and the
bad.
Finally we are now faced with the incredible length of service life which can be achieved by an aircraft
of one type. Often, in place of new prototypes are aeroplanes which have been stretched and added to. One
case in point is the De Havilland Comet, the first jet airliner anywhere, the prototype of which flew in 1949. Its
buried wing-root jet engines were at first rejected by other designers, in place of the podded wing-mounted
units favored by the Americans. However, over the intervening half-century the Comet was metamorphosed
through the Royal Aircraft Establishment at Farnborough as an experimental test-rig. Its shape further evolved
into the maritime reconnaissance backbone of the RAF, growing a deep weapon-bay and an array of
electronic intelligence equipment, radar and, through several variants, into the glass-cockpit Nimrod 2000,
which is expected to serve well into the 2020s. The buried engines are still there, as turbofans, their mounting
within the wing roots provides a degree of stealth, impossible with podded units. If it serves out its life as
planned it will then be 80 years since the basic Comet was first sketched on a table cloth — or so the legend
has it.
In the early 1960s the author was one of the experimental test pilots at Farnborough whose reports
contributed to the American McDonnell Douglas F-4 Phantom entering service with the Royal Air Force. A
quarter of a century later his eldest son was flying them operationally in the Falklands: a time-span akin to
taking an aeroplane into service in 1915 and flying it in combat in the Battle of Britain in 1940. One
consequence of such longevity is that there are teams working in airframe and engine design offices of various
manufacturers who might never see anything they have designed actually fly.
Do not be discouraged though. There is work to be done by use of the air, un-thought of previously. It
is a time of consolidation and adaptation. Operationally, the world is bigger and more complex than ever
before. That such size and complexity exist is the best justification for this book, and the second and third
which followed — the Design of the Aeroplane (1983) and Flying Qualities and Flight Testing of the Aeroplane
(1996) — making this the first of a trilogy.
All three books are a practical consequence of cross-fertilization between design, operations, test flying
and, years ago, the author leaving his milk-teeth on the factory floor during World War II, as an apprentice in
aeronautical engineering. In short, as far as the eye can see into the next millennium, there are broad new
fields opening and waiting to be explored by you, and others like you, in our use of the air for more than simply
breathing, burning and polluting.
Darrol Stinton
Farnham, 1997
Theory and practice. Schlieren photo of wind tunnel model of a Lightning (a), and a Lightning (b) and a
Phantom (c) of the RAF, showing similar effects of shock wave formation in moist air
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