Engineering Science
Science leads to
applied science leads to technology--NOT
SO
(or not always)
What are the
possible
relationships between science and technology:
- new scientific discovery
provides the basis for a new technology
- use scientific
information
or research to improve an existing product
- new science can grow out
of
trying to understand existing technology
- scientists develop
instruments for scientific research that turn out to be
useful for
other things
- engineers can use the
scientific method and do their own research
Physics couldn't tell you anything useful about
aerodynamics until after World War II. Therefore aviation
is a
good example of the
complex ways in which engineers use science.
Systematically vary the relevant parameters and
learn the relationships (eg. between wind shape and lift).
Represent the results
as a mathematical relationship or as a table of data
The invention of the airplane:
- Flight had been a dream for a long time,
but
generally by direct analogy to birds and therefore with
flapping wings (Leonardo).
Balloons
came into use in the late 18th century and saw significant
use in
the Civil War and for sport, so there was some familiarity
with the
atmosphere
as an environment.
- By the end of the 1800s gliders
had been flown
successfully and a number of people were working on powered
gliders.
- The Smithsonian Institution's head, Samuel
Pierpont
Langley, had a government grant to build a
heavier-than-air
craft.
His approach was to "urge a system of rigid planes through
the air at
great
velocity," in other words like running a knife through
butter. He
visualized
air as a series of identical elastic cubes.
Langley
Aerodome--National Air and Space Museum
- He tested one design before the Wright
brothers,
but couldn't get off the ground. But he owned the
Washington
establishment--nobody paid any attention to the Wright
Brothers.
- the Wright brothers
emphasized the fluid nature
of air, and sought a plane that was flexible and adjustable,
not rigid.
- Now mind you, they were not scientists,
but
they
were bicycle-makers and racers who read the professional
literature,
studied the problems of aviation with great care and
corresponded with
other aeronautical researchers such as Octave
Chanute.
The Wright brothers even built their own wind tunnel--6
feet long and 16 inches square to study the relationship of
various
wing
shapes and lift and also propellers. Some of the other
researchers were
professional engineers and scientists, but the Wrights could
do just as
good
empirical research.
- they developed a system to turn the plane
with
a rudder linked to a system to warping
the
entire wing so that the plane
would bank in flight, tested it extensively in
gliders. They
built
their own gasoline
engine, because they could not find a suitable one on
the market, and a much more efficient propeller.
They
successfully
flew a powered airplane Dec. 17, 1903 (for more
on the
Wright
Brothers and their process of invention--and lots of pictures
and
quick-time
movies--see To
Fly
is
Everything )
Wright
Brothers flight, National Air and Space Museum
the Wright brothers had a terrible time
interesting
anyone
in their success--the U.S. military did not purchase its first
plane
until
1909
- Europeans were more
interested, and during World War I learned to use aircraft
for reconnaissance, bombing,
and fighting
- when the U.S.
entered World War I in 1917, we lagged
far behind in military aircraft
- In the year before the U.S. declared war
the
U.S. aviation
industry produced 411 planes, though a large number of
airplane
engines were shipped to Europe by one company partnership
that had
designed
a good lightweight engine and techniques for mass-producing
it (the
Liberty
Engine, Packard and Hall-Scott).
- by the end of the war in 1919 the army
had
5,500
planes, though most of the fighters were purchased in
Europe. The
U.S.
industry did successfully produce trainers, and many planes
were in
production
when the war ended
French
Spad WWI fighter--National Air and Space Museum
there was a need for
research also, or at least coordination, and it almost instantly
outgrew the resources of amateurs like the Wright brothers or
even the
small firms that were building
aircraft.
- The National
Advisory Committee on Aeronautics was
one of a number of organizations created as a result of
lobbying by
scientists and engineers for a new government role in
research and
development in World
War I.
- President Wilson signed the naval
appropriations
bill that created the National Advisory Committee on
Aeronautics in
March
1915. The scientists, engineers and enthusiasts who
had lobbied
for
the bill for more than four years wanted government funding
of
aeronautical
research to allow the United States to catch up with rapid
developments
in
Europe. But the legislation did not pass until the
outbreak of
war
provided an additional push, and the bill did nothing more
than create
an
advisory committee and provide it with a small
appropriation.
- The NACA then set out to invent its own
role.
In its first few years the new Committee played a
significant role in
the wartime coordination of industry and used some of its
small budget
to sponsor research at private institutions, but its leaders
made the
building of a
new laboratory their highest priority. The laboratory
at Langley Field,
in Virginia, established the NACA as a federal research
agency despite
its
title as an advisory committee. After the war ended,
debates over
the
role of the federal government in supporting and regulating
aviation
created
considerable uncertainly about the future of the NACA, but
the final
result
strengthened the Committee's emphasis on research because
other
aviation-related
functions--regulation and the sponsorship of
infrastructure--were
assigned
to the Department of Commerce. The federal government
also helped
the aviation industry by funding air
mail service.
- At the Langley
Memorial Laboratory, dedicated in
June 1920, NACA scientists and engineers set out to invent a
role for
the
federal government in peacetime aviation research. The
laboratory
provided fairly up-to-date facilities: a wind
tunnel, an engine-dynamometer laboratory, and a general
research
laboratory building.
- The laboratory developed a focus on
aeronautical
principles both in order to take advantage of its wind
tunnel
facilities
and to avoid competition with the military services (which
wanted to
maintain
control of testing and setting specifications for new
aircraft designs
for
miliary missions) and the National Bureau of Standards and
industry
(which
had facilities for engine research).
- The NACA found a niche not only in its
choice of
research program but also in how it approached research
problems: "The
strength of the NACA seems to be that it had the luxury of
pursuing
incrementally over
a long period of time answers to problems that were of great
interest
to
the commercial and military worlds."
- The leaders of the NACA initially thought
that
the committee had to establish its reputation by scientific
(not
engineering)
achievement, and hired Max
Munk from
Germany because of his theoretical reputation. Munk
made a key
discovery, that by compressing the air in a tunnel you could
use scale models in wind tunnels to provide results that
would
correlate with
data from a full-sized plane in actual use. This idea
was put
into
use in a 5 foot diameter variable density tunnel in 1923,
and then was
followed
by a 20 foot diameter tunnel for full scale research in
1927.
NACA's
first
wind
tunnel
- the NACA used the large tunnel for
research
on propellers, landing gear, and drag. They discovered
that the
engine provide as much
as 1/3 of the plane's total drag, and invented
a way to cover the engine
to enhance cooling while reducing drag. During a test
a plane that normally averaged 157 mph averaged 177
mph. But this
wasn't a theoretical breakthrough--each cowling was custom
developed
for
a particular combination of airplane and engine by wind
tunnel
experiments.
detail from Diego Rivera mural at Detroit Institute of Art
- The necessity of practical results to
justify federal funding and the dominant role of engineers
on the NACA
main committee gradually reversed that attitude,
establishing the
relationship between theoretical and practical research as a
central
tension within the laboratory and the agency as a whole.
Development of Aeronautical Engineering:
- Expertise spread: in 1929 1400 students
were
studying aero-engineering in more than a dozen schools.
- Meanwhile, aircraft design was developing
in
the
1920s and 1930s as the market finally began to expand again.
- Ford
trimotor of 1926--metal structure and cantilevered
wing.
Ford
Trimotor, National Air and Space Museum
- People began to predict
that soon there would be an
airplane in every garage
- Aluminum propeller developed in 1925, and
variable
pitch propellers by the end of the decade.
- The first successful helicopter
flew in Germany
in 1936; Russian emigre Igor Sikorsky
had a U.S. design in tests by 1939
and got a contract from the army in 1940
Sikorsky's
first
helicopter
research became more complex.
- As aviation technology became more
complex
in the late interwar period, the NACA found itself
sponsoring not only
research on components and design parameters but large-scale
research
and development projects.
- World War II brought a return to more
practical
concerns, but with the greater emphasis on government-funded
technology
characteristic of the war years it also provided the NACA
with broader
experience in large development programs and some push to
take bigger
risks.
- Perhaps most notably, members of the
aviation community saw supersonic flight as the next step,
but making
that step required both theoretical research, wind tunnel
testing, and
actual building of experimental aircraft. Those
experimental
aircraft were no longer prototypes of new
military aircraft, but now were designed solely for research
purposes.
- The NACA therefore found itself in the
business
of contracting with industry for the design and manufacture
of
radically
new vehicles. The X-15
project supersonic test vehicle project in particular
differed little in scale and scope from space projects of a
few years
later.
X-15--National
Air
and Space Museum
Engineering science is systematic experimentation
aimed
at seeing the overall patterns, not just solving specific
practical
problems.
It may be simply empirical work, but it aims at describing
patterns,
hopefully
in equations.
this page written and copyright
Pamela E. Mack
History
122
last updated 10/8/2003