Category Archimedes

CONCLUSION

The story recounted here was, in sum, about the success and the failure of Leonard Bairstow. The whole story turned on the scientific and technological significance of the key instrument for aeronautical research: the wind tunnel. Bairstow made full use of it, defended the validity of the data from it, and argued for the continuation of model research in it. He further promoted the attempt to standardize the performance of wind tunnels all over the world and to accord the NPL a central role. For all these efforts to connect the inside and the outside of the laboratory, I compared him to a laboratory director in Latour’s Science in Action and Pasteur in Pasteurization of France.

At first, Bairstow was exceptionally successful. His prewar stability research was applauded at home and abroad. Despite an American request, the British regarded it too important to disclose. Through such accomplishment, Bairstow attained fellowship in the Royal Society, served on the Air Board, and became Professor of Aeronautics at Imperial College. He became an extremely powerful figure in the British aeronautical community.

Bairstow’s position would have been further enhanced had the NPL model of wind tunnel research been standardized around the world. That was one object of the decade-long International Trials project. During this project, however, it turned out that Bairstow’s previous argument for ignoring the scale effect was called into question. Prandtl’s new aerodynamic theory challenged Bairstow’s position. French use of the Prandtl correction sparked a scientific debate on the validity of Prandtl’s aerodynamic theory. Acceptance of the Prandtl correction implied criticism of Bairstow, who had insisted on the negligibility of the scale effect.

While Bairstow served as an excellent middleman between theoretical scientists and practical engineers in conducting model research on stability, he failed to be such a middleman between Teddington and Famborough. He might have been more sensitive and generous to the full-scale experimenters at Famborough, initiating a theoretical and experimental research program on scale effect. Instead, he defended his model research like a lawyer at court by pointing out possible weaknesses in full-scale testing. Perhaps the wartime emergency and the position of the Air Board prevented him from taking a more discreet stance on this matter. In any event, he left himself open to later criticisms and repudiation. In the end, the renamed Scale Effect subcommittee approved the desirability of constructing a new variable-density wind tunnel developed by American engineers. This was a clear judgment that Bairstow had been wrong.

If we take Latour’s argument seriously, we could pose a question. Why did Prandtl’s theory prevail in the postwar world? From 1904, when he arrived at Gottingen, to 1918, the year of armistice, Prandtl succeeded, like Bairstow, in conducting aerodynamic research and expanding his research facilities. But after the war, he was placed in severely limited conditions on poor financial and material bases and with almost no communication with foreign investigators. Yet his aerodynamic theory soon won over aeronautical engineers all over the world. It was mainly not through Prandtl’s own effort but through the efforts of foreign engineers, and his disciple in the case of the United States, that his theory was accepted worldwide. In this connection, we could turn our attention to the RAE engineers who championed the introduction of Prandtl’s theory in Britain. In arguing for the validity of the German theory and specifically promoting the application of Prandtl correction, they succeeded in restoring the position held by their colleagues at Famborough in the wartime scale-effect controversy.64

INDUSTRY-ORIENTED ENGINEERING EXCHANGE

The BDV and B-29 Committees were product-specific cooperative organizations. Creating broader industry-wide cooperation fell to a number of groups, the most prominent of which was the Aircraft War Production Council (AWPC). Begun in April of 1942 by eight of the largest Southern California aircraft manufacturers, the AWPC was an unusual departure from normal peacetime competitive operations. It involved the transfer of knowledge, materials, labor, and facilities among former rivals.33 One of the intriguing characteristics of the AWPC was the wide-ranging mandate to share any information that could aid the prosecution of the war. The Board of Directors, composed primarily of the presidents of the West Coast Companies, strongly supported exchange and set a clear policy for Council activities:

It is the instruction of the Board of Directors that members of the Advisory Committees shall be free to interchange all information which will help the war production of the company receiving the information, without regard to protection of manufacturing processes which in normal peace times might be regarded as a secret.34

The sentiment was genuine and followed resolutely by the committees. Like the BDV and B-29 Committees, many of the market-based obstacles normally hindering technology transfer among competitors in peacetime were thus removed. Similarly, the AWPC did not simply lower corporate barriers; it established direct channels for exchange. AWPC Committee workers had strong incentives to cooperate with each other since their immediate superiors in the Council were also likely to be their superiors at their respective companies (see figure 7).35

While never completely isolated from each other before the war, the manufacturers generated much of their engineering information, especially production information, in-house. The principal exception to this was wind tunnel data, the province of affluent institutes and organizations. The challenge for the Council was to establish means not only for sharing information, but generating it cooperatively. Encouraging disparate groups to exploit outside information led to special efforts to tailor information retrieval to the likes of engineers. Mutual engineering research, like cooperative aircraft production schemes, would eventually take on the methodology of standardization in order to make research results portable. The regularity of exchange, while not a direct indicator of

INDUSTRY-ORIENTED ENGINEERING EXCHANGE

Figure 7. Founders of the AWPC. From left to right: Harry Woodhead (Consolidated), Donald Douglas (Douglas), La Motte Cohu (Northrop), J. H. Kindelberger (North American), Richard Miller (Vultee), Courtland Gross (Vega), and Robert Gross (Lockheed). Source: Frank Taylor and Lawton Wright, Democracy’s Air Arsenal New York: Duell, Sloan and Pearce, 1947, 45.

successful technology transfer, indicates that at a minimum there was significant demand for outside information.

As early as 1936, the southern California manufacturers had begun their own in­house technical libraries. With the outbreak of war, it was to the Pacific Aeronautical Library (PAL), begun in 1941, that they turned as the locus for technical exchange. Operated by the Institute of Aeronautical Sciences, the PAL quickly became a natural partner to the AWPC and was ultimately subsumed into the Council itself in 1943. Collection, indexing, and exchange were the library’s three functions, and it became the principal means for publicizing and transferring written information between companies.36

While the PAL did serve as a simple repository, its real strength lay in its ability to make a wide range of materials available to professionals. In October, 1942, the librarians began an indexing project oriented towards engineers and comprising materials well beyond the PAL’s own collection. Finding traditional subject headings inappropriate for aircraft design and production, the librarians created their own. The standard indexes, including the Library of Congress subject headings, the Engineering Index, and the Industrial Arts Index, approached aviation in far too general terms. In consultation with workers from local companies, the librarians exploited the engineer’s lexicon. For example, they classified materials by vendors or trade names rather than under broadly scientific material categories. To satisfy the needs of both the design and production aspects of aircraft manufacture, topics were given multiple entries (for example, one applying to a particular material, another applying to the processes surrounding that material). Furthermore, the PAL attempted to be all inclusive, a single reference point for all matters. The index comprised articles from all the relevant engineering and trade journals, including NACA and SAE publications.37 Eventually the PAL index came to include the collections of member companies, creating a meta-collection available to everyone. Engineers could thus easily order information and have it quickly copied and delivered. Interchange among companies, institutes such as Caltech, and the PAL grew large enough to require a messenger service that traversed a 120-mile route between libraries and companies twice a week.38 The PAL’s indexes were reprinted many times over, being sent to manufacturers across the US and the NACA.39

As table 1 indicates, the PAL served customers throughout the local aviation community. Reinforcing the idea that the PAL acted as an information service, as opposed to a simple repository, is the high percentage of research questions asked relative to other services; they account for over 36% of the total. It is also interesting to note that Vega exploited the service the most, even though it was a smaller company compared to Douglas, Lockheed Aircraft Corporation, and North American Aviation. One probable explanation is that the larger companies were much more self-sufficient, and that the PAL was relatively more important to smaller firms, including subcontractors like Adel Precision Products Corporation and AiResearch. As this was a formative period in aircraft industry subcontracting, technology transfer and the establishment of basic aeronautical expertise would have been critical to these smaller companies.

The operation of a central library fulfilled only a small portion of the Council’s technology transfer goals. A principal objective – eliminating duplicated research among manufacturers – remained for the Council’s committees. The airframe firms continually carried out research in many areas, not just product design, but tests on materials and production processes too. These activities are not well known since the reports were normally proprietary, and tended to be destroyed as newer information superceded the old. They were directed at very specific design and production issues, giving information on how to do something, as opposed to why something occurs. In this, they were quintessential^ engineering, not scientific reports. Table 2 gives the results of the October 1943 survey in which the Engineering Committee found a total of 321 different research projects at all member companies (for an average of 49 projects per company, per month).40 Aside from the sheer volume of research, it should be observed that little of it was in the area traditionally associated with aircraft research – aerodynamics, which had the least number of projects of any other category. Not only was theoretical research a small fraction of the overall research scheme, but studies on manufacturing problems were as numerous as those on design-oriented research. Such research differed from traditional corporate research and development in that it was not restricted to a laboratory setting. What we might call production-design research took place at many levels throughout the factory and

Table 1. Pacific Aeronautical Library Statistics (10/42 to 9/43)

Company

Circulation

Research Questions By Phone In Person By Mail

Readers

Vega

738

668

20

1

97

Lockheed

391

485

15

87

Douglas

367

278

43

57

119

Northrop

271

213

24

76

Airport Ground School

448

21

31

257

AiResearch

284

157

13

28

16

North American

194

113

19

96

31

Vultee

148

138

6

5

28

Adel

185

111

1

1

11

Hughes

202

59

29

1

61

Interstate

75

31

5

10

Fedders

10

8

3

1

4

Miscellaneous

873

384

134

8

583

Total

4186

2666

343

198

1380

Source: Meeting Report, Librarians Specialists Panel, 4 November 1943, Committee Reports on Production Division (October 15 – November 15, 1943), box 24, NAWPC.

involved a wide variety of personnel, including engineers, technicians, tooling designers, and machinists. The research represented a systematic effort to quickly produce locally valuable design data, including design data for production.

The extent to which companies shared this information with each other can be gleaned from AWPC Engineering Committee statistics. Unfortunately only a partial record of these statistics remain, as indicated by table 3. Many different things

Table 2. Active Research Projects of AWPC Member Companies, October 1943

Research Category

Subtotal

Total

Material Investigations

67

Metals

38

Plastics

21

Lubricants

4

Miscellaneous

4

Manufacturing Investigations

86

Cementing

2

Sealing

9

Finishes and Coatings

22

Welding and Brazing

23

Metal Forming

17

Plastics Working

3

Riveting

7

Inspection Methods

4

Instruments and Testing Equipment

13

Electronic Test Equipment

9

Mechanical Test Equipment

4

Tooling Investigations

2

Structures and Strength Investigations

68

Structural Research

33

Fatigue and Vibration Research

18

Rivets and Fastenings

17

Power Plant

15

Hydraulics

11

Heating and Ventilating

8

Aerodynamics

2

Miscellaneous

12

Armament

11

Electrical and Radio Investigations

25

Source: Meeting Report, Engineering Committee, 9 Oct. 1943, Committee Reports on Production Division (September 15 – October 15, 1943), box 24, NAWPC.

Table 3. AWPC Engineering Committee Information Exchange Statistics

Member

Company

Exchanges To East Coasf

To Non­Members

Inter­

Plant

Visits

Drawings

Manuals

Reports

Monthly

Total

New

Reports

To Dec. ’42

703

177

880

Nov. ’42

156

39

195

Dec. ’42

198

58

274

Mar. ’43

549

119

58

726

July ’43

394

64

70

528

Aug. ’43

189

54

34

277

19

Dec. ’43

348

13

37

398

115

Jan.-Feb. ’44

223

636

859

April ’44

264

96

32

54

143

589

210

June ’44

76

34

8

85

102

305

240

Sept. ’44

211

159

14

54

130

568

181

Oct. ’44

81

184

6

73

138

482

156

Nov. ’44

31

66

0

44

84

225

70

To Dec. ’44b

9,056

1,848

1,236

809

2,318

15,276

5,195

Sources: Meeting Report, Advisory Committee on Engineering, 2 Jan. 1943, Committee Reports on Production Division (December 1942), box 22, NAWPC; Meeting Report, Advisory Committee on Engineering, Committee Reports on Production Division (January 1943), box 22, NAWPC; Meeting Report, Advisory Committee on Engineering, 3 April 1943, Committee Reports on Production Division (March 15 – April 15, 1943), box 22, NAWPC; Meeting Report, 7 August 1943, Committee Reports July – Aug. 1943, box 23, NAWPC; Meeting Report, 4 Sept. 1943, Committee Reports Aug. – Sept. 1943, box 23, NAWPC; Meeting Report, 8 January, 1944, Reports on Committee Activities August 1944, box 23, NAWPC; Meeting Report, 6 May 1944, Reports on Committee Activities June 1944, box 25, NAWPC; Meeting Report, 8 July 1944, Reports on Committee Activities, box 25, NAWPC; Meeting Report, 9 Dec. 1944, Reports on Committee Activities January 1945, box 25, NAWPC; Warplane Production 2, no. 3-4 (March – April 1944).

a The AWPC EC number presumably is for information sent to the AWPC EC, since the Engineering Committee would not have been interested in how other organizations were benefiting the AWPC.

b The cumulative figures are those given by the AWPC. This includes some material that is not reflected in the given monthly numbers.

qualified as an incident of engineering exchange, though all of the data listed falls in the information category, as opposed to tooling or material exchanges. For the given sample, exchange between member companies accounts for 60 percent, while exchange with the East Coast accounts for 12 percent, and non-members for 5 percent. Because the Council was specifically interested in the amount of time saved through cooperation, Table 3 does not include duplicated reports. Additional statistics show that many of these engineering reports were reprinted many times over. For example, in August 1943, the AWPC mailed a total of 22,582 articles, 10,193 engineering reports, and 319 miscellaneous publications. Respective totals from the beginning of AWPC operations in April 1942 to the first of September, 1943, 17 months, are: 179, 241; 91,284; and 319.41

Underscoring the inability of written information to communicate all engineering knowledge was the role played by interplant visits. For the months in which they were included in Council statistics, they count for about ten to twenty percent of total exchange. Sometimes plant visits were incorporated into a panel’s meetings. For example the May meeting of the Subcommittee on Tooling Coordination took a tour of the Boeing plants in Renton, Washington. Minutes from the meeting note the following:

The Committee met at 10:00 a. m. and a tour was conducted through both Plant #1 and Plant #2 where the manufacture of roll forming, curving and stretching of sheet metal was in process. The committee was very interested in our methods of manufacture, and special interest was shown in the movable stretching tables built by Consolidated. The tour came to an end at 12:30 p. m. Discussion was then opened on the subject, and Mr. Englehardt, General Foreman of the Metal Bench Department, answered all questions asked pertaining to rolling, curving and stretching of sheet metal parts.42

This kind of interaction represents the height of tacit knowledge transfer. These processes existed in physical form on the plant floor and in the activities of the laborers. Such practices rarely warranted internal reports or studies, and in some cases, might only be known to shop workers. For example, it came to the attention of the Testing and Research Panel that “it is apparently common practice for draw press operators to heat aluminum alloy in warm water just before drawing.”43 Meetings between tooling engineers would have been insufficient to communicate all such facets of a production system. Instead, interplant visits were a crucial method of communicating differences in engineering practice and shop culture. Even in cases where there was published information, plant tours could be highly educational. In one instance, members of the Project Group of the Methods Improvement Panel touring the Northrop factory were able to each try their hand at Northrop’s Heliarc welding process44

On the occasions where the Council found common problems among the manufacturers, it often initiated cooperative research projects, or at least brought existing research groups together. Here again, the critical exchange of engineering information was impeded by differing traditions. In many cases, Council committees and subcommittees resorted to methods of standardization in order to overcome these divides. As such, standardization can be considered a means of achieving technology transfer. For the AWPC, standardization was unlike the SAE’s efforts in the automobile industry, where common parts, materials, and measures permitted external economies. Rather, the standardization of things like test procedures permitted the exchange and comparison of engineering knowledge. It permitted one company’s test results to be compared against another’s. This produced an external economy of a different kind, one based on abstract technical data rather than physical parts or materials. While the AWPC had removed proprietary restrictions on the exchange of data in 1942, it would require standardized company practices before data were truly interchangeable. Standardization efforts did not end there though. AWPC committees standardized language, defects, procedures, and training.

Standardization was not only a means of achieving internal and external efficiencies, it was a familiar method of establishing order and creating novel systems of engineering knowledge. It implied the exchange of best-practice technology as well as the consensual definition of what was appropriate behavior for a worker, an engineer, or a manufacturing firm. The pervasive and continued recourse to standards activities by engineers was due in large part to the fact that this was an extremely familiar form of engineering exchange within the context of industrial coordination. The AWPC committees themselves had been established in a manner very similar to the SAE’s committees, both characterized by technical expertise, small groups with a tight focus, company representation, and industrial coordination.45

CONCLUSION

In the early days of mobilization, it was commonly assumed that America’s industrial strength could be redirected towards the mass production of armaments. In an atmosphere of hopeful naivete, planners believed in a kind of design – production modularity, where one company’s high-performance designs could be transferred to another company’s high-performance production system. Ultimately the country did convert to wartime production and achieve remarkable success in the mass production of aircraft. Yet it required a painful education, one that exposed the extent to which design and production were embedded within a company’s engineering culture and traditions of practice. One might be able to explain away Ford’s well known difficulties in producing the B-24 as simply a case of inter­industry technology transfer, but just as many problems appeared among longtime members of the aircraft industry.

In ways that are often invisible to engineers and managers within a company, the mixing and matching of design and production systems and widespread technology transfer illuminates the nature of engineering information. Engineering knowledge is not solely the province of the research engineer or the product designer. Nor is it embodied succinctly and completely in numerical data or technical drawings. On the way to the final product, information is both lost and accrued. In an ironic turn to the historiography of technology as knowledge, we find engineering knowledge

embodied in physical artifacts, not simply in the final product as we would expect, but in design and production. In tools, machinery, processes, and plant layout, information is perpetuated within a company, reinforcing workplace traditions while simultaneously reflecting workers’ traditions of practice.

The process of production, hidden by scholarly emphasis on product design and performance, complicates our understanding of engineering knowledge. For the manufacturing firm, the ability to design and produce is not the function of a single engineer, but of an organization. We can neither presuppose that design exists outside of production, nor model the factory as a linear process from idea to finished product. Underlying this argument are the different factory actors who execute some manner of design: aeronautical engineer, structural engineer, production engineer, tooling engineer, machinist, foreman, worker, and occasionally, manager. The engineering department may arrive at what it believes to be a complete design, but what rolls out the factory doors will in all likelihood be a different product.

The historical circumstance of wartime cooperation is itself remarkable. The quantity of exchange, where it is documented, is staggering. Both the product – oriented and industry-wide organizations found ways to transfer information, however ungainly they might seem to those who believe in the power of the technical drawing. Drawings were complemented by thousands of master gages, jigs, fixtures, tools, and the occasional example aircraft. Where documents and physical devices could not guarantee precision, these organizations resorted to the exchange of personnel. Interchangeable airplane assemblies were as much a result of practice as they were of accurate measurement. So too, the AWPC promulgated standardized procedures in order to make engineering information interchangeable. Standardization served to expunge critical differences in culture and practice.

What this history tells us is that for many years prior to World War II, firms developed their own ways of doing things. They were content with their handling of engineering information so long as it produced the desired artifact. In manufacturing, companies are held to the success of their product, not the outside reproducibility of their engineering information, as in a scientific laboratory. World War II subjected the production process to new scrutiny as manufacturers attempted to understand why engineering information was not truly portable. In the end they found that production systems were as varied and idiosyncratic as the aircraft they produced.

TECHNICAL ADVANCE IN AVIATION

The starting point for any discussion of technical advance in aeronautics is the landmark study of Ronald Miller and David Sawers, The Technical Development of Modern Aviation:66 One of the authors, David Sawers, had collaborated on an earlier and even more famous investigation, The Sources of Invention,67 In the latter work, Sawers and his co-authors had studied fifty cases in order to determine how industrial inventions arise in the modem world. A second edition added ten new case studies.68 Only two of the inventions, helicopters and the jet engine, were peripherally related to the aircraft manufacturing industry.69 Nonetheless, the general conclusions had wide applicability.

The study found a trend away from the lone inventor of previous ages to large, institutional sites. In these, creative genius counts for less than enlightened management. All are vulnerable to ossification as they grow large and old. Eclecticism usually triumphs over monolithic agendas and methodologies. There is no consistent relationship between monopoly and invention, but the patent system, for all its imperfections, remains important to the individual inventor or the small firm.

Miller and Sawers sought to test these conclusions in their investigation of aircraft development.70 What they found was an industry in which progress was not steady and incremental but rather episodic and pivotal. Writing in the late 1960s, amidst the U. S. policy debate over whether or not to proceed with development of a supersonic transport, Miller and Sawers found only ten aeronautical inventions after the Wrights and Curtiss to have been seminal. They are listed in slightly modified form in Table l.71 Others might argue for a longer list, but this one serves the purposes of this paper.

It also provides a chronology that helps to understand how and when aeronautics made its greatest advances. The Germans, say Miller and Sawers, made the greatest technical contributions. Partly for that reason, Europe led the United States in aircraft development until the late 1920s. Following Lindbergh’s flight, however, American aviation caught up quickly. The airframe revolution of the early 1930s, much of it based on German innovations, catapulted the United States into the lead in commercial airliners. While the Europeans devoted much of their attention to the development of fighter aircraft between the wars, the United States focused instead on bombers and long-range airliners, both powered by air-cooled engines and both placing a premium on range and payload. Depending in part on government-funded research for the military, the American aircraft industry achieved a 33% cost reduction in airliner operations between 1927 and 1933.72 The experience was repeated in the 1960s, when the first American jet airliners, the Boeing 707 and the Douglas DC-8, were introduced.

Miller and Sawers found what the previous Sources of Invention had found: there is no dominant pattern of technical development. While “technical progress… seems to have been rapid” in the aircraft industry, the inventions themselves came in many different ways.

Подпись: Invention Подпись: Dates Подпись: Countries

Подпись:

Подпись: Aerodynamic knowledge permitting designs of well-streamlined airplanes Cantilever monoplane Slotted wing Flaps (four successive innovations) Cowling of radial engines Variable-pitch propeller Stressed-skin metal construction Jet engine Swept-back wings Variable-sweep wings Подпись: England, Germany, U.S.
Подпись: 1910-1915 Germany, Franсe 1917-1919 England 1908-1924 England, U.S., Germany 1921-1928 U.S., England 1923-1929 England, Canada, U.S. 1914-1929 Germany, U.S. 1929-1936 England, Germany 1935-1939 Germany 1941-1958 Germany, U.S., England

Table 1.

Some were made in times of prosperity – which, for the aircraft industry, usually means war – and some in depression. Some were based on scientific discoveries; others were straight inventions based on the state of technical knowledge where any was appropriate, the recognition of need by an alert mind, or a more or less chance discovery.73

The aircraft industry itself produced a low level of invention; most ideas came from outside, many of them from universities and government laboratories.

Patents, say Miller and Sawers, “have rarely been important in the development of the airplane.”74 Advances in aerodynamic efficiency and supersonic flow, for example, do not often take patentable form. Manufacturers guard new designs as proprietary information until it is made public by incorporation on an aircraft. Outside inventors, in contrast, are reduced to seeking royalties from manufacturers on those developments, such as wing flaps, that are easily patentable. These conclusions highlight two characteristics of the patent system that ill suit it for aeronautical developments. It forces disclosure of information in exchange for protection and reward, a trade-off that some industries find disadvantageous. And it focuses more on mechanical artifacts than on designs and processes, which are central to aviation progress.

For these reasons and others, say Miller and Sawers, the aircraft manufacturers embraced the Manufacturers Aircraft Association and the patent pool. “The existence of the MAA,” they believe, “is mostly evidence of the unimportance of patents in the aircraft industry, but it reduces their importance still more.” Innovation has been important to the American aircraft industry, but patents have not. Furthermore, the patent pool has undermined the outside inventor by reducing the incentive of any single manufacturer to purchase rights to an invention. In the final analysis, however, “one cannot blame the MAA for the lack of invention in the American industry. It seems to be more an effect than a cause of this condition.” The proof of this, they believe, is that the British industry, which has no patent pool, has shown no greater inventiveness.75

Other analyses of the American aircraft industry have come to similar conclusions. John Newhouse, for example, attributes competition in the aircraft industry to operating efficiency, engineering integrity, configuration of aircraft, and price.76 As the industry has contracted down to fewer and fewer giant firms, there has been a tendency to associate innovation with survival. The continuous, incremental, cumulative refinement of aircraft design, usually conducted below the patent threshold, is often lost to view amidst these market forces.

Robert Ferguson’s exploration of World War II aircraft production in the United States reinforces these findings. He discovered that shop-floor practice and unpatentable, short-term, localized research often accounted for the technical gains made during the war.77 Companies did use patents, but primarily to establish postwar claims of primacy and to provide modest incentives for employees.78 For example, the Guerin patent for sheet-metal pressing of aluminum fuselage, described by one authority as “the greatest single contribution to the manufacture of all-metal airplanes,” was freely shared within the industry during the war, different manufacturers adapting it to their particular shop-floor practice and culture. “No two companies,” notes Ferguson, “designed or produced aircraft in exactly the same manner,” so that even when they used the same specifications, they often manufactured differently and produced slightly different products. For all these reasons, “during the war, patents did not play a significant role in the transfer of technology” in the aircraft industry.79

Nor do patents loom large in the case studies in aeronautical engineering that Walter Vincenti has used to explore What Engineers Know and How They Know /L80 It might be expected that patents would embody what engineers know and therefore play a large role in these stories. But “patent” does not appear in the index, and patents do not play a significant role in Vincenti’s analysis. They appear in his account of flush riveting, but mostly in the footnotes; patents seem to have little impact on the process that interests Vincenti most, the way in which knowledge of this important technique circulated within the aircraft manufacturing industry.81

Patents play a somewhat larger role in Vincenti’s account of the Davis Wing. Inventor David R. Davis invented an airfoil profile, which he then shopped around the aircraft industry. Davis creatively got around the disclosure aspect of patents by withholding from his patent application two unspecified, assignable constants, lacking which his formula was useless. The Davis wing came to be used on the 19,000 B-24 bombers built by Consolidated Aircraft in World War II.82 This, the largest production run of any bomber in history, no doubt enriched Davis and made him famous as well. But Vincenti doubts that the secret Davis wing section really contributed much to the great range achieved by the B-24. “High aspect ratio and other features of the airplane,” says Vincenti, have greater explanatory power.83 His larger point is that the real source of aeronautical development lies in the great diversity of engineering knowledge and the various ways in which that knowledge is accumulated and transferred.

Unlike Ferguson and Vincenti, Seymour Chapin addresses patents explicitly in his analysis of an important aeronautical technology, cabin pressurization.84 More precisely, he studies a costly and consequential struggle over patent interferences in the introduction of automatic rate-of-pressure change controls in the 1930s and 1940s. Patent interferences occur when two or more parties file patent applications for similar inventions that make overlapping claims. In this case, researchers at Boeing Aircraft Corporation and Douglas Aircraft Company filed patent applications for automatic rate-of-pressure change controls within two years of each other, in 1937 and 1939 respectively. Both were building on previous work that had been funded by the Army. Had the companies retained the rights to the patents, the dispute could have been handled within the Manufacturers Aircraft Association, where the arbitration board would have determined the licensing fee due to either or both of the companies. But Boeing granted licensing rights for its device to a new firm, AiResearch Manufacturing Company, which was not a member of the MAA. This dispute dragged through the Patent Office review system throughout the 1940s, finally to be decided in Douglas’s favor in 1950. AiResearch urged Boeing to appeal or to sue for reversal, arguing that it had already paid Douglas close to $1 million in royalties, with the prospect of still higher rates if the decision stood.

But Boeing had had enough. Patents were granted to both applicants, in 1951 and 1952 respectively, and Douglas’s device continued to win significant royalties. Boeing, of course, did not have to pay that market rate, for it was licensed to use the Douglas patent through the cross-licensing agreement. But AiResearch did have to pay, and Boeing had to forgo the royalties it would have received from AiResearch had its patent prevailed. Patents may not have played a major role in the technical development of American aviation, but they could still command significant sums of money in those instances where they did appear.

Analysis of U. S. aircraft patents from 1900 to 1996 reinforces the conclusions of these case studies. Figure 1, showing total aircraft patents, indicates no decline when the cross-licensing agreement was created nor any immediate increase when it was abolished. The steepest spikes accompany the public demonstrations of the Wright airplanes in 1908, the Lindbergh flight of 1927 and the airframe revolution of the early 1930s, and the introduction of commercial jet airliners in the late 1950s. When aircraft patents are taken as a percentage of total patents (see figure 2), different trends are revealed. Steep rises during the world wars indicate that other industries tended to decrease patenting activity during the wars more than the aircraft industry did. Furthermore, aircraft patenting has declined relative to other industries ever since the peak associated with the introduction of jet propulsion in commercial service. The overall patterns in these data confirm Miller’s and Sawers’ belief that major innovations in aviation have been few and far between. Most of the remarkable refinement of the modem airliner has come in small increments outside the patent system.

TECHNICAL ADVANCE IN AVIATION

00 03 06 09 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84 87 90 93 96

Figure 1. U. S. Department of Commerce, Patent and Trademark Office, USPAT file, at North Carolina State University. Aircraft Patents are Classification Number 244.

Aircraft patents as a percentage of total patents

TECHNICAL ADVANCE IN AVIATION

00 03 06 09 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84 87 90 93 96

Figure 2. U. S. Department of Commerce, Patent and Trademark Office, USPAT file, at North Carolina State University. Aircraft Patents are Classification Number 244.

CONCLUSIONS

All the literature and all the data point to the same conclusion: patents have not been important in the development of aircraft manufacture in the United States. This answers some of the questions posed at the beginning of this study. Historians have neglected patents in aviation history because they did not play a large role after the early years. The patent pool appeared and survived because some such mechanism was needed in those early years, and it did little harm and perhaps some good thereafter.

But these conclusions leave unanswered the most vexing question: why was it that patents played so little role in the technical development of airframe manufacture, and what was driving that development? The answer to that question is complex and layered. It requires pulling together the findings of this study under five main headings.

First, the expectation that patents would play a role lacks warrant. Technical development does not necessarily depend upon, nor even correlate with, patenting. This is especially true in cumulative industries such as aircraft manufacture. In these cases, pioneering patents often dominate the field for a number of years. Thereafter, with the foundational ideas already introduced, the total body of knowledge at play is large and cumulative. New ideas are relatively less important. This seems to have been the case in aircraft manufacture. Technical development in this field has been continuous and significant, but it has proceeded incrementally below the patent threshold. Lucrative, important patents such as those for cabin pressurization devices, did appear from time to time, but they were comparatively few.

Second, airframe manufacture came to be conducted in a corporate environment increasingly less conducive to patenting. The industry gravitated from small companies reflecting the style and inventiveness of their founders to large corporations in which technical innovation flows from large, impersonal teams.85 Patents do issue from such institutions, but they are less important to these sponsors than they are to the lone inventor. Jacob Schmookler has found, for example, that as corporations grow larger, they pay more for research and realize fewer patents.86

Third, government funding of aeronautical research grew more important as the century proceeded. In universities and industry, as well as in its own laboratories, the government financed as much as 85% of aerospace research. Government and university laboratories were less inclined than industry and individuals to patent their developments. Even industry had less incentive to patent inventions made with government funds, for their contracts usually required free licensing to the government. Often the inventions of one industry contractor were shared freely by the government with others, further diminishing the value of patents.

This government-funded research, most often conducted under military auspices, was the principal way in which the United States subsidized aeronautical development. Many other countries adopted models of national airlines and research laboratories, directly supported by government funds. The United States eschewed such models, but found other, less obvious ways to support its aerospace industry. Research and development on military aircraft were often transferred to civilian aircraft, either through direct applications by companies such as Lockheed and Boeing that made both, or indirectly through publications such as NACA research reports that provided data applicable to both types of aircraft.87 This mechanism for the dissemination of research results became especially important during the Cold War, when aerospace research in the United States was driven by strategic and political considerations to be the best in the world. Spin-off from that research fueled the commercial aircraft industry throughout the second half of the century.

Fourth, in this competitive environment, companies often preferred proprietary knowledge over patents as a way of protecting their ideas. Indeed, patents were often avoided for the very reason that they made inventions public. An invention published in a patent could often be worked around faster by the competition than if it were kept secret until incorporated in an actual aircraft, whence the competition would have to reverse-engineer it, master its production, and redesign an existing plane to install it as a modification. As far back as the 1930s, aircraft manufacturers who came to NACA wind tunnels to test their aircraft and components were more interested in maintaining proprietary secrets than they were in patenting.88

Maintaining proprietary information in this industry was a difficult proposition. Aerospace engineers are mobile professionals. Companies can raid the staffs of their competitors to hire expertise and knowledge. Alternatively, some engineers may find themselves laid off, especially in the boom-and-bust atmosphere that came to surround the assignment of large contracts to increasingly fewer firms in the late Cold War. Furthermore, as aerospace engineering became more professional through the twentieth century, more and more members sought career advancement through publication. Walter Vincenti’s account of the development of flush riveting, for example, shows that even as companies and government employees were taking out patents on techniques of flush riveting, others were publishing the results of their research in the open literature. His account of the ways in which ideas about flying qualities circulated in the aeronautical community provides still more evidence of the multiple avenues of communication through which knowledge could travel.89 Keeping up on the state of the art, even as it advanced rapidly, was comparatively easy to do.90

But the free circulation of people and ideas did not mean that inventions in one firm were necessarily transferrable to another, at least not directly. Each of the major aerospace manufacturers developed a unique culture of management, design, and shop floor practice. So distinct were these cultures during World War II, that, according to Robert Ferguson, some firms could not replicate exactly the product of other firms even when they worked from identical specifications and plans.91 This points up the unusual tension between standardization and hand­crafting that has always shaped aircraft manufacture. Aircraft defy the kind of automation that has overtaken, for example, the automobile industry. Airframes are still put together by hand, albeit in an assembly-line style. Therefore, shop floor practice leaves its imprint on the final product far more than in other standardized industries.92 Know-how from one environment might require considerable adaptation to work in another.

This last point emphasizes a fifth and final reason why aircraft manufacture came to depend less on patenting than might have been expected. Specific inventions in this field, in the form of devices, are often less important than design and process. In aircraft manufacture, production economies and competitive advantages are more often achieved through superior design and efficient manufacture than through superior components. The cabin pressurization devices studied by Chapin, for example, were similar in their effect and both were workable. The patent fight was not over which was better but which was first. When Douglas won that fight, Boeing simply worked around the patent to install on its aircraft a functionally comparable device. This sort of skirmishing, while it entailed significant royalty payments, was not the kind of development that accounts for the rise of Boeing or the decline of Douglas. It is possible to win patents for designs and processes, but companies seldom invested their energies this way. Rather, they developed their own style and relied on that to give them economic advantage in the marketplace. Real competitive advantage in the aircraft manufacturing industry came from practice, more than it came from patentable ideas.

As the aircraft manufacturing industry in the United States contracted over the course of the twentieth century, it became both more and less competitive. It was less competitive in the simple sense that there were fewer competitors. But it was more competitive in the sense that each remaining competitor was larger, had more resources, and risked more in a market with fewer buyers. The industry moved toward oligopoly while the market moved toward oligopsony.93 In such an environment, marketing and business decisions loomed larger; the price of the aircraft and its operation and maintenance counted for more than technical features, which tended to be similar across the industry. And as always, the single most important determinant of aircraft operating efficiency was the engine, a technology that always fell outside the cross-licensing agreement.

For all these reasons, patents have grown less salient in airframe manufacture than in U. S. industry in general (see figure 2). Individual decisions to seek a patent were no doubt shaped by these considerations and others, depending on particular circumstances. This account cannot begin to explain how those decisions were made. But it does provide some conceptual tools for thinking about aggregate patenting behavior in this field.

THE EVOLUTION OF AERODYNAMICS IN THE TWENTIETH-CENTURY:. ENGINEERING OR SCIENCE?

INTRODUCTION

The field of aerodynamics is frequently characterized as an applied science. This appellation is simplistic, and is somewhat misleading; it is not consistent with the engineering thought process so nicely described and interpreted by Vincenti.1 The intellectual understanding of aerodynamics, as well as the use of this understanding in the design of flight vehicles, has grown exponentially during the twentieth – century. How much of this growth can be called “science”? How much can be called “engineering”? How much falls into the grey area called “engineering science”? The purpose of this paper is to address these questions. Specifically, some highlights from the evolution of aerodynamics in the twentieth-century will be discussed from an historical viewpoint, and the nature of the intellectual thought processes associated with these highlights will be examined. These highlights are chosen from a much broader study of the history of aerodynamics carried out by the author.2

For the purpose of this paper, we shall make the distinction between the roles of science, engineering, and engineering science as follows.

Science: A study of the physical nature of the world and universe, where the desired end product is simply the acquisition of new knowledge for its own sake.

Engineering: The art of applying an autonomous form of knowledge for the purpose of designing and constructing an artifice to meet some recognized need.

Engineering Science: The acquisition of new knowledge for the specific purpose of qualitatively or quantitatively enhancing the process of designing and constructing an artifice.

These distinctions are basically consistent with those made by Vincenti.3

There is perhaps no better example of the blending of the disciplines of science, engineering science, and pure engineering than the evolution of modem aerodynamics. The present paper discusses this evolution in five steps: (1) the total lack of technology transfer of the basic science of fluid dynamics in the nineteenth century to the design of flying machines at that time (prior to 1891); (2) the reversal of this situation at the beginning of the twentieth century when academic science discovered the airplane, when the success of Lilienthal and the Wright brothers

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proved the feasibility of the flying machine, and when academicians such as Kutta and Joukowski developed the seminal circulation theory of lift and Prandtl introduced the concept of the boundary layer, all representing the introduction of engineering science to the study of aerodynamics (1891 – 1907); (3) the era of strut and wire biplanes, exemplified by the aerodynamic investigation of Eiffel, who blended both engineering science and engineering in his lengthy wind tunnel investigations (1909 – 1921); (4) the era of the mature propeller-driven airplane, characterized by the evolution of streamlining, representing again both engineering science and engineering; (5) the era of the modem jet propelled airplane, including the revolutionary development of the swept wing (see also the companion paper in this volume, “Engineering Experiment and Engineering Theory: The Aerodynamics of Wings at Supersonic Speeds, 1946 – 1948,” by Walter Vincenti). In the final analysis, we will see that the naive “engineering versus science” alluded to in the title of this paper fails to hold up, because the evolution of aerodynamics in the twentieth century was characterized by a subtle integration of both.

ASPECTS OF AMERICAN AIRPORT DESIGN BEFORE WORLD WAR II

INTRODUCTION

The “modem” American commercial airport was invented during the two decades before the start of the Second World War. This opening statement has to be written in the passive voice because while it is easy to speak of the invention of airports, there are no inventors – no “Wright Brothers” – responsible for this remarkable technological system which makes commercial air transportation possible. This paper explores a major aspect of the “invention” of airports which was the process of standardization of airport design. In particular, it emphasizes the interaction between and among three separate groups of professionals – engineers, architects and city planners.

The idea that airports were technologies which needed to be designed, let alone something which required the services of “experts” to undertake, did not always exist. Orville Wright argued in a special editorial for Aviation magazine in 1919 that: “The airplane has already been made abundantly safe for flight. The problem before the engineer today is that of providing for safe landing.”1 Few paid much attention to Wright’s pronouncement though. Commercial air transportation entrepreneurs and other aviation enthusiasts wanted to emphasize the image of an airplane whizzing freely through the sky unhindered by all earthly obstacles. Above all else, this preoccupation with unfettered speed worked to eclipse a nascent discussion about the infrastructure needed to transform civilian aviation from mainly a random and recreational activity to a regular and commercial operation.

As various enterprises got underway, most notably the U. S. Post Office’s Air Mail Service, attitudes changed. Whether pilot or passenger (or even just the shipper of a letter or parcel), only the knowledge that it was possible to depart safely and then later return to earth made flight desirable. Consequently, interest in the details – the technical problems associated with safe landing – became paramount. Subsequent sections of this paper describe how first engineers, then architects, and finally city planners came to form a partnership of experts whose coordinated services were required for the design of airports. The creation of this specialized technical community helped fix the fundamental design, shape and purpose of the commercial airport, as well as the technologies and techniques to build and operate them.

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The few historical accounts of airport development assume (either explicitly or implicitly) a deterministic relationship between airplane and airport. In other words, the size, shape, weight and speed of the airplane determined the physical characteristics of the place for taking-off and landing. Standardization of airport design then, it is argued, is a consequence of the emergence in the 1930s of the “modem” airliner, most especially the Douglas DC-3.2

Closer examination reveals a different story. Powerful political, economic, and cultural forces profoundly influenced airport design; even more than the performance characteristics of airplanes (which for commercial transports only rarely were designed to exceed the capacity of the existing infrastructure). Especially important to understanding this history is the story of the formation of the unusual interdisciplinary technical community responsible for airport design. It would be an alliance among professionals more typically noted for their extreme professional rivalry. Yet, there was more cooperation than conflict and that fact is critical to understanding how airport design was standardized.

This is not to say that there was no professional rivalry but the “struggle” among engineers, architects and city planners was limited.3 The relative harmony came through the steady expansion of the definition of what constituted the technological functions of an airport. Increasing consumer demand for air transportation profoundly shaped the technology of airports. So too did the participation of the federal government. The partitioning of a technological design problem does not necessarily result in positive relations among the participants but in this instance these factors served to mitigate conflicts. At the start of World War Two, this cooperative working arrangement among engineers, architects, and city planners mediated by government officials was manifest in an airport system design that had become a “normal technology.”4

PERORATION

These conclusions about the MAA raise one final irony. The criteria used by the Justice Department in 1972 to rationalize breaking up the Manufacturers Aircraft Association soon proved to be inappropriate. The Antitrust Division had identified nine restrictions that it believed should be applied to patent licensing. Restriction number two forbade a patentee from requiring a licensee to assign to the patentee any subsequently acquired patents.94 The cross-licensing agreement did this, and it was on this basis that the Justice Department filed against the MAA. By 1973, however, the Justice Department began to appreciate that these restrictions were, in the words of the Chief of the Intellectual Property Section of the Antitrust Division, “economically counterproductive in that [they] discouraged investment in R&D and discouraged efficient licensing of patents.”95 This revelation did not, however, stop the wheels set in motion in the U. S. District Court in New York. The same Justice Department that endorsed the cross-licensing agreement in 1917 brought it to a close in 1975. The agreement probably did restrain trade in 1917; it probably did not in 1975. The Justice Department got it wrong both times.

ROLES OF SCIENCE AND ENGINEERING IN NINETEENTH-CENTURY AERODYNAMICS

To understand the relationship of science and engineering to aerodynamics in the twentieth-century, we need to examine briefly the completely different relationship that existed during the nineteenth-century.

The history of aerodynamics before the twentieth-century is buried in the history of the more general discipline of fluid dynamics. Consistent with the evolution of classical physics, the basic aspects of the science of fluid dynamics were reasonably well understood by 1890. Meaningful experiments in fluid dynamics started with Edme Mariotte and Christiaan Huygens, both members of the Paris Academy of Science, who independently demonstrated by 1690 the important result that the force on a body moving through a fluid varies as the square of the velocity. The relationship between pressure and velocity in a moving fluid was studied experimentally by Henri Pitot, a French civil engineer in the 1730’s. Later in the eighteenth-century, the experimental tradition in fluid dynamics was extended by John Smeaton and Benjamin Robins in England, using whirling arms as test facilities. Finally, by the end of the nineteenth-century, the basic understanding of the effects of friction on fluid flows was greatly enhanced by the experiments of Osborne Reynolds at Manchester. These are just some examples. In parallel, the rational theoretical study of fluid mechanics began with Isaac Newton’s Principia in 1687. By 1755 Leonhard Euler had developed the partial differential equations describing the flow of a frictionless fluid – the well-known “Euler Equations” which are used extensively in modern aerodynamics. The theoretical basis of fluid mechanics was further enhanced by the vortex concepts of Hermann Von Helmholtz in Germany during the mid-nineteenth-century. Finally, the partial differential equations for the flow of a fluid with friction – the more realistic case – were developed independently by the frenchman Henri Navier in 1822 and the englishman George Stokes in 1845. These equations, called the Navier-Stokes equations, are the most fundamental basis for the theoretical study of fluid dynamics. They were well-established more than 150 years ago.

Thus, by the end of the nineteenth-century, the basic principles underlying classical fluid dynamics were well established. The progress in this discipline culminated in a complete formulation and understanding of the detailed equations of motion for a viscous fluid flow (the Navier-Stokes equations), as well as the beginnings of a quantitative, experimental data base on basic fluid phenomena, including the transition from laminar to turbulent flow. In essence, fluid dynamics was in step with the rest of classical physics at the end of the nineteenth-century – a science that was perceived at that time as being well-known, somewhat mature, with nothing more to be learned. Also, it is important to note that this science was predominately developed (at least in the nineteenth-century) by scholars who were university educated, and who were mainly part of the academic community.

The transfer of this state-of-the-art in fluid dynamics to the investigation of powered flight was, on the other hand, virtually non-existent. The idea of powered flight was considered fanciful by the established scientific community – an idea that was not appropriate for serious intellectual pursuits. Even Lord Rayleigh, who came closer than any of the scientific giants of the nineteenth-century to showing interest in powered flight, contributed nothing tangible to applied aerodynamics. This situation can not be more emphatically stated than appears in the following paragraph from the Fifth Annual Report of the Aeronautical Society of Great Britain in 1870:

“Now let us consider the nature of the mud in which I have said we are stuck. The cause of our standstill, briefly stated, seems to be this: men do not consider the subject of ‘aerostation’ or ‘avia­tion’ to be a real science, but bring forward wild, impracticable, unmechanical, and unmathematical schemes, wasting the time of the Society, and causing us to be looked upon as a laughing stock by an incredulous and skeptical public.”

Clearly, there was a “technology transfer problem” in regard to the science of fluid dynamics applied to powered flight. For this reason, applied aerodynamics in the nineteenth-century followed its own, somewhat independent path. It was developed by a group of self-educated (but generally we//-educated) enthusiasts, driven by the vision of flying machines. These people, most of whom had no formal education at the university level, represented the early beginnings of the profession of aeronautical engineering.

For example, this community of self-educated engineers was typified by the following: George Cayley, who in 1799 enunciated the basic concept of the modem configuration airplane; Francis Wenham, who in 1871 built the first wind tunnel; Horatio Phillips, who in 1884 built the second wind tunnel and used it to test cambered (curved) airfoil shapes which he later patented; Otto Lilienthal (who did have a bachelors degree in Mechanical Engineering), who carried out the first meaningful, systematic series of experimental measurements of the aerodynamic properties of cambered airfoils,4 and later designed and flew extensively the first successful human-carrying gliders (1892 – 1896); and Samuel Langley, 3rd Secretary of the Smithsonian Institution, who carried out an exhaustive series of well-planned and well-executed aerodynamic experiments on rectangular, flat plates,5 but who had two spectacular failures in 1903 when a piloted flying machine of his design crashed in the Potomac river.

Langley clearly stated the prevailing attitude in his Memoir published posthumously in 1911.6

“The whole subject of mechanical flight was so far from having attracted the general attention of physicists or engineers, that it was generally considered to be a field fitted rather for the pursuits of the charlatan than for those of the man of science. Consequently, he who was bold enough to enter it, found almost none of those experimental data which are ready to hand in every recognized and reputable field of scientific labor.”

Langley considered himself one of the bold ones. This is particularly relevant because in the United States at the end of the nineteenth century the position of Secretary of the Smithsonian was considered by many as the most prestigious scientific position in the country. Here we have, by definition, Langley as the most prestigious scientist in the United States, and he is turning the tables on the scientific community by devoting himself to the quest for powered flight.

However, the prevailing attitude abruptly changed in the space of ten years, beginning in 1894.

DON’T TRUST AN ARMY MAN!

Archibald Black was a budding entrepreneur who found his niche as an airport engineering expert in the early 1920s. Bom in Scotland in 1888, Black emigrated to the United States in 1906 and became a citizen in 1913. His education was something of a hodge-podge, including three years at New York City’s Cooper Institute, plus courses at the Cass Technical Institute in Detroit and Columbia University’s extension school. Black became an electrical engineer and worked on a variety of electrical and construction jobs until discovering aviation in 1910. In 1915 he began working for Curtiss Aeroplane Company in 1915, transforming a hobby into a full-time vocation. Within a year, he had become an airplane designer for Curtiss. In 1917, he took a new job as chief engineer for L. W.F. Engineering Company where he designed the first airplane to incorporate the famous Liberty engine. A wartime stint in the Navy brought him to Washington where he was put in charge of preparing all of the Navy’s aeronautical specifications.5

After the war, he began a long and productive career as a consulting engineer. Over the decade he would emerge as the most influential figure in the design of

American airports. But it was with much bravado that the 33-year old would assert in a letter to Secretary of Commerce Herbert Hoover that: “in addition to being the most experienced consulting engineer in this field in the country, the recent dissolution of a competing firm now makes ours the oldest also.”6 It was a bold claim that said more about the newness of aviation than it did about Black’s engineering expertise.

Still, within a year, Black had managed to gain quite a bit of attention for himself. His article, “How to Lay Out and Build an Airplane Landing Field,” appearing in Engineering News-Record, was selected for reprinting by the National Advisory Committee for Aeronautics in its Technical Memorandum Series. Aerial Age said the paper was “probably the first really constructive discussion of the subject published.”7 Black, who had spent much energy beating the drums in a generic pitch for the contributions engineers could make to aviation, suddenly found a rhythm which resonated. While he never lost his broad interests in advancing commercial air transport, Black became a champion for “scientifically arranged landing fields in America.”8

In 1922, landing fields (the word airport was not in common usage until the late 1920s) for airplanes did not seem like much. In comparison with the stupendously complex civil engineering design projects for bridges, tunnels, canals, railroads, and hydroelectric dams, the small square (usually) sod fields with a wooden hanger, a gas tank, and a wind cone hardly seemed to demand the services of an expert, let alone a specially-trained engineer. Appearances were deceiving according to Black. Even in his earliest articles, he argues for careful planning based on significant technical knowledge of civil and mechanical engineering, meteorology, and construction technology. The term “scientifically arranged” referred only to the design of a facility which enabled aircraft to get in and out of the air.

Thus, Black’s early articles emphasize that the shape and size of the plot required the detailed scrutiny of meteorological data. The sky was not benign and aircraft were fragile. Soil samples were required to design the surfaces for take-off and landings. Regular use required a prepared surface able to bear the loads exerted by an airplane. There were formulas for calculating the impact of obstacles such as trees or tall buildings, landing gear stresses, and how much grass seed should be sown. The type and arrangement of buildings needed to be optimized for safety and functionality. And finally, it was necessary to develop various communications systems that enabled ground personnel to relay vital information to airborne pilots.9

Black was not the first to suggest these things, however. Desperately casting about for a postwar mission, aviation officers in the Army embraced the idea of sharing with the public the knowledge gained during the war. Right after the war the Army had decided to plan its own national airway system and had begun to survey potential sites for airports. That work was endorsed by President Harding who stated during a special message to Congress in April 1921 that the Army Air Service should take the lead and aid the “establishment of national transcontinental airways, and, in co-operation with the states, in the establishment of local airdromes and landing fields.”10

Harding’s pronouncement led to the establishment of the Airways Section within the Training and War Plans Division of the Air Service the following December and the creation of a “Model Airways” program in June 1922. Fulfilling its obligation for the “promulgation of information pertaining to airdromes and airways,” the Air Service issued “Airways and Landing Fields,” a new Information Circular in March 1923.11

Like its earlier “Specifications for Municipal Airports,”12 this Army circular includes details about what constituted an ideal landing field. The Army “ideal” was developed in the context of an expanded model airway that served, first and foremost, military objectives which were to provide for the aerial defense of the nation. The Army had included in the specifications for its very first airplane (ordered from the Wrights in 1908) that the airplane be easily disassembled and, preferably, easily shipped in a standard Army wagon crate 13 After the war, however, the Army expected to be able to fly from base to base. The typical range of aircraft in the early twenties required frequent stops (indeed, the working assumption of the time was that safety required an airfield every 10-25 miles). Lieutenant F. O. Carroll, a Landing Field Officer for the Army Air Service, wrote that the Army would follow along the same routes of the Conestoga pioneers and continental railroads. His challenge was to “arouse the interest and secure the co-operation of the cities in this important national enterprise, and make them see that their future and the future of the country depends on the establishment of landing fields.”14

What the Army wanted most of all was air fields that conformed to a set of standards. Recognizing that all communities could not afford to build the same sort of facility, the specifications proposed four classes of landing fields. A fourth class field was for emergency use only; its landing surface might be just a narrow strip of land about 600 feet in length. The very best, the first class field, would be a square field at least 2,700 feet in any direction. The surface for landing and taking-off would be improved – level, smooth, sodded and well-drained. All approaches to the field would be free from obstacles such as telephone poles, electrical lines, trees and tall buildings. The field would be well marked with a landing circle (a large white circle, 100 feet in diameter, set into the ground), wind direction indicators, and the name of the facility in 15 foot high letters. Finally, a well-developed field had hangars, shops, gasoline, oil, telephones and transportation to the nearest town. Second and third class fields had slightly smaller dimensions and fewer amenities although standards for marking the field remained the same. There was little change in the basic requirements for air fields between 1920 and 1922, although the “square” field design was no longer the only preferred landing field shape – An “L” shaped field was considered almost as good as the square-shaped field.15

There were some who felt the Army’s vision for airways and airports left something to be desired. It was not the generic vision of a well-functioning system of airports and airways that was problematic to these individuals. Rather it was the belief that the Army’s own airfields had little to commend about them and that most Army officers were unable to render good advice on how to design and build an airport. The leading critic was the engineer, Archibald Black. Black’s main purpose in making his complaint was to lend support to his conviction that the best possible training for a would-be airport designer was engineering. Pilots, of course, had a great interest in airports, but Black believed that merely possessing the skill to pilot an airplane was not adequate qualification to design an airfield.16

Black actually had three related concerns. His first concern related to the quality of existing Army air fields. The tremendous urgency to build military air fields during the war had meant relying on firms which had neither experience in designing and building such facilities nor the time to make a thorough study of the problems that were unique to aviation. This observation was not intended to be an indictment of either the Army or the construction companies. Rather, Black believed that given the poor result there was “no reason for ignoring past experience and common sense, and arranging fields without careful consideration of the entire subject beforehand.”17

Black’s second concern about relying on the Army example was that subsequent to the war, some of the fields the Army had completed were of very high standard – too high to be meaningful for the average municipality. “Army equipment,” he wrote, “is considerably more elaborate than is likely to become necessary at municipal fields for some time.”18 In one article scrutinizing various airport designs, Black was equally critical of fields that were too large or elaborate as he was of small or “carelessly” organized layouts. The former represented unforgivable profligacy with public monies; the latter were safety hazards.19

Black’s third and most doggedly asserted criticism was reserved for “the customary practice of consulting some local hero, in the person of a former Army pilot.. ..”20 The veteran pilot while worthy of veneration was unlikely to be familiar with both air field design and current commercial aircraft technology. Black repeated this assertion at every opportunity. In American City he wrote, for example, “it is more advisable either to obtain the services of a specialist or to appoint, as a substitute, a well-rounded committee to do the planning. Any other policy may prove surprisingly expensive at some later date and the cost may be counted in human lives as well as in dollars.”21

The resolution to all these concerns, according to Black was to establish airport design as an engineering function. Thus, the essence of good design was one which placed safety paramount, followed by the careful expenditure of funds.22 His fullest statement on this subject was in an article written for Landscape Architecture in 1923. The piece, “Air Terminal Engineering,” began: “The selection, arrangement and construction of aircraft landing fields and other types of air terminals represent an entirely new phase of engineering which is yet very much in the paper state.”23 The benefits to relying on an “airport engineer” were three-fold. First and foremost, while a bad design would absolutely result in crashes, a good design would prevent costly accidents. Second, good design would result in the best overall construction price. And third, Black believed an engineer was best suited to determine the airport location, as well as to plan the buildings at the facility to take advantage of existing ground transportation and power, water, and telephone utilities.24

Black had recently returned from a European study trip and his head was swimming with details related to airport construction. It was in Europe that he first formed the belief that airports ought to be engineered. He was especially enthusiastic about the developments at Croydon Airdrome in London. There were three airports in London but Croydon had become the city’s main commercial facility after the war. Black was undeniably impressed by what he saw but two things seem to have been especially influential – Croydon’s airport lighting system and its carefully designed landing area surface.25

In his influential Engineering News-Record article, it becomes especially clear why Black believed airport design should be done by engineers. In this article, Black makes a strong case for special analytical skills an engineer might bring to the problem of design. Existing grass fields were fast proving inadequate. As the number of airplanes taking off and landing at any given airport increased beyond a small handful, the sod-covered surfaces rapidly disintegrated. Airplanes of this period were all “tail-draggers” and their skids carved deep gouges into rain-softened surfaces. The Army had experimented with concrete landing and take-off crosses. Black urgently warned readers about the pitfalls of concrete as a landing surface (it was fine for taking off). In addition to the great expense, it was too smooth for an era when airplanes did not have brakes and pilots relied on a rougher surface to slow down the vehicle.26

There was a prevalent misconception that turf was “softer” than concrete and therefore safer. Black dismissed such ideas. The landing gear and tires of an airplane were designed to bear specific loads; one surface or another made little difference to the airplane (assuming the initial design was adequate). Based upon Black’s analysis of airplane tire sizes and their normal loads, he readily concluded that most landing surfaces were not adequate. He became an early advocate for “runways,” special strips 75 feet wide and 1000 feet long. Runways were part of the larger landing surface area but they would be specially designed and constructed to carry the full load of an airplane during take-off and landing. This necessitated careful preparation of the subgrade as well as some kind of special surfacing. It also required renewed attention to drainage matters. Conventional roads relied on crowning as the central element of drainage design but Black found that such curved surfaces were very hazardous.27

Black pursued his studies of runways, consulting with highway engineers as well as experts at the Bureau of Public Roads. In later articles (and books) he provided much more substantial discussion of runway surfaces as well as providing specifications and cost analysis information.28 These articles were of noticeably different character from the literature being supplied by the Army which continued in the “do-it-yourself’ manner. What Black wanted to demonstrate was that airport design would only mature when the designers were able to comprehend fully the assumptions and methods employed by aircraft engineers in the design of airplanes. Black, who had spent several years designing aircraft, believed that the symbiotic relationship between airplane and airport could be best characterized in engineering terms – in a language of speed, power, weight, size, wing loading, power loading, lift, drag, and aspect ratios. The development of airports and airplanes needed to proceed in a coordinated fashion or commercial aviation would falter. These lessons became especially ingrained during his tenure with the group of engineers writing the Aeronautic Safety Code. By 1925, it was clear that Black had made his point, although the full impact of it would not be perceived until the passage of the Air Commerce Act in May 1926.29

DISCUSSION PAPER

I

All the papers in this collection are highly accomplished exercises in the history of technology but, of course, they represent history of somewhat different kinds. For example, they assume different positions along the so-called “internal-external” dimension. Profs. Smith and Mindell’s admirably detailed history of the turbo fan engine largely, but not wholly, falls into the “internal” category, as do the authoritative accounts by Prof. Vincenti of work done in supersonic wind tunnels, and Prof. Suppe on the instrumentation used in test flying. Of a more “external” character are papers dealing with the economic, institutional, and legal setting of aeronautical activity, such as Profs. Crouch and Roland’s discussion of patents or Prof. Douglas’ account of the different professional inputs to airport design. Again on the “externalist” side we have Prof. Jakab’s account of the hypocrisy and profiteering surrounding the emergence of McCook Field.

Apart from the “internal – external” divide we also have other kinds of variation. Some papers are clearly more descriptive, while some are more explanatory. I think it is true to say, however, that most contributors have chosen to keep a low profile when it comes to questions of methodology or theory. This is a wise strategy. Concrete examples often speak louder than explicit theorizing. Readers can put their own gloss on the material and see for themselves points of contact with other ideas. Nevertheless it is in the area of theory and method where I may have a role to play. I am not an historian of technology, indeed I am not an historian at all, and I have no expertise in aerodynamics. My comments will all be from the standpoint of sociology. I shall focus on what I take to be the more significant sociological themes that are explicit, or implicit, in what has been said. I shall try to suggest ways in which sociological considerations might be brought into the discussion or where they might help in taking the analysis further. Adopting a sociological approach biases me towards what I have called the “external” end of the scale, but there are some points of contact with the more technical, “internal” discussions, and I shall do my best to indicate these. Here I shall be struggling somewhat, but for me these points of contact between the social and the technical represent the greatest challenge, and the greatest interest, of the whole exercise.

II

Let me begin with Prof. Galison’s paper. His claim, and I think he makes it convincingly, is that aircraft accident reports are beset by an unavoidable

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P. Galison and A. Roland (eds.), Atmospheric Flight in the Twentieth Century, 349-360 © 2000 Kluwer Academic Publishers.


indeterminacy. Investigators confront an enormously complicated web of circumstances and actions. How is this manifest complexity to be handled? There are two possible directions in which to go. One direction is to narrow down the explanation of the accident on to one or more particulars and highlight these as the cause. We will then hear about the Captain who chose to take-off in bad weather, or the co-pilot who was not assertive enough to over-rule him, or the quality control inspector who, years before, let pass a minute metallurgical flaw. The other direction leads to a broader view, embracing a wide range of facts which can all be found to have played a contributory role in the accident. Had the de-icing been done properly? Was the company code of practice wrong in discouraging the use of full – throttle? What is it that sets the style and tone of group interaction in the cockpit? Who designed the three hydraulic systems that could be disabled by one improbable but logically possible event? Accident reports, he argues, tend to oscillate between specific causes and the broad range of other relevant particulars.

Prof. Galison has put his finger on a logical point similar in structure to that made famous by the physicist Pierre Duhem in his Aim and Structure of Physical Theory (1914). No hypothesis can be tested in isolation, said Duhem. Every test depends on numerous background assumptions or auxiliary hypotheses, e. g. about how the test apparatus works, about the purity of materials used, and about the screening of the experiment. When a prediction goes wrong we therefore have a choice about where to lay the blame. We can, logically, either blame the hypothesis under test, or some feature, specified or unspecified, of the background knowledge. Prof. Galison is saying the same thing in a different context. No causal explanations can be given in isolation. Whether we realize it or not, the holistic character of understanding always gives us choice.

How are those in search of causes to make such choices? Prof. Galison tells us not to think in terms of absolute rights or wrongs in the exercise of this logical freedom. The unavoidable fact is that there are different “scales” on which to work. This, “undermines any attempt to fix a single scale as the single ‘right’ position from which to understand the history of these occurrences” (p.38). What, then, in practice inclines the accident report writer to settle on one or another strategy for sifting the facts and identifying a cause? Legal, economic and moral pressure, we are told, has tended to favour the sharp focus. This has the advantage that it offers a clear way to allocate responsibility: this person or that act was responsible; this defect, or that mechanical system, was the cause. The utility of the strategy is clear. Individuals can be shamed or punished; and a component can be replaced. Now, we may be encouraged to feel, the matter is closed and all is safe again.

Is this a universal strategy rooted in some common feature of human understanding, or near universal social need? Do accident reports from, say, India and China, have the same character as those from France and America? Or are some cultures more holistic and fatalistic and others more individualistic and litigious? It would be a fascinating, though enormous, undertaking to answer a comparative question of this kind. Prof. Galison gives us some intriguing hints to be going on with. In his experience there is not much difference between, say, an Indian and an

American report. What stand out strongly are not broad cultural differences but sharp conflicts of a more local kind. While the National Transportation Safety Board blames a dead pilot, authoritative and experienced pilots dismiss the report as pedantic and unrealistic. While official American investigators point to the questionable behavior of the control system of a French built aircraft under icy conditions, the equally official French investigators point the finger at the crew who ventured into the bad weather. Prof Galison speaks here of the “desires” of industry, of the “stake” of pilots, and of the “investment” of government regulators, as well as economic “pressures”. All of these locutions can be brought under the one simple rubric of ‘interests’. The phenomenon, as it has been described, is structured, strongly and in detail, by social interests. Let me state the underlying methodology of Prof. Galison’s paper clearly and boldly. It is relativist, because it denies any absolute right, and depends on what is sometimes called an ‘interest model’. As we shall see, these challenging themes weave their way through the rest of the book as well, and inform much that is said by the other contributors.

Ill

A number of papers take up a comparative stance – perhaps the most explicit being Prof. Crouch’s discussion of the differential enthusiasm with which governments encouraged aviation in Europe as compared to the United States. It wasn’t the Wright brother’s insistence on taking out patents that held back American aviation, it was lack of government awareness and involvement. Prof. Roland takes up the story of patents to show how the earlier shortcomings were later dramatically repaired. Once the government had got the message, expedient ways were found for circumventing legal issues. One of the themes of Prof. Roland’s paper is that of a culture of design, craft-skill and engineering expertise. His point is that if anything inhibited the flow of information and expertise it wasn’t patents, it was the localized character of engineering practices and the desire to keep successful techniques away from the gaze of competitors. So significant was this local character of engineering knowledge that when different firms came to produce aircraft or components according to the same specifications, they still turned out subtly different objects. Prof. Ferguson gives a stunning and well-documented example of this. He looks at the wartime collaboration of Boeing, Douglas and Vega in producing B-17 bombers. Despite the intelligent anticipation of such problems, and a determined attempt to overcome them, these three companies could not build identical aircraft. The ‘same’ tail sections, for example, proved not to be interchangeable. The lesson, and Prof. Fergusen draws it out clearly, is that practical knowledge does not reside in abstract specifications (not even in the engineer’s blue prints.) Knowledge is the possession of groups of people at all levels in the production process. It resides locally in their shared practices. The problem of producing the same aircraft remained insurmountable as long as the three local cultures survived intact and in separation from one another. It was only overcome by removing, or significantly weakening, the group boundaries. This was done by deliberately making it possible for people to meet and interact. In effect, it needed the three groups to be made into one group.

Others tell us of similar phenomena. Profs. Smith and Mindell speak of the different engineering cultures of Pratt and Whitney, on the one hand, and General Electric, on the other. General Electric’s rapid and innovative development of the CJ 805 by-pass turbofan engine was helped by their recruitment of a number of key engineers from NACA. Again, we see that knowledge and ideas move when people move. Smith and Mindell characterize the culture of Pratt and Whitney as “conservative” – and explain how, nevertheless, contingencies conspired to ensure that its incrementally developed JT8D finally triumphed over the product of the more radical group at General Electric. Their history of the triumph of the Pratt and Whitney engine shows how different groups produce different solutions to the same problem. Add to this their discussion of the Rolls Royce Conway, and the debatable question of which was the ‘first’ by-pass engine, and we have another demonstration of the complexity of historical phenomena and the diversity of legitimate descriptions that are possible. Finally, they address the general question of why turbo-fan engines emerged when they did – some twenty five years after Whittle and Griffith had suggested the idea? The concept became interesting, they argue, because of decline in commitment to speed and speed alone as the arbiter of commercial success in civil aviation. Turbo-fans could succeed economically in the high sub-sonic realm in a way that jets could not. We are dealing with new measures of success, “measures that embody social assumptions in machinery” (p.47). This pregnant sentence once again gives an interest-bound and relativist cast to the argument.

The theme of the local engineering culture, whether it be Pratt and Whitney versus General Electric, or Boeing versus Douglas, strikes me as sociologically fascinating. And it is, of course, something calling out for comparative analysis. How many kinds of local engineering culture are there? Are there as many cultures as there are firms? Ferguson’s work suggests that there are, and that we are dealing with a very localized and sharply differentiated effect. Nevertheless, even if local cultures are all different from one another, they might still fall into classes and kinds, perhaps even a small number of kinds. If they were to fall into a small number of kinds then comparison should enable us to see the same patterns repeating themselves over and over again. This might allow us to identify the underlying causes of such cultural styles. Calling Pratt and Whitney “conservative” might tempt us to think in terms of a dichotomy, such as conservative versus radical. Other dichotomies, such as open societies versus closed societies, or Gemeinschaft versus Gessellschaft, the organic versus the mechanical, or markets versus traditions, will then suggest themselves as models. But there are other options. Why work with a dichotomy? If we follow the suggestions of the eminent anthropologist Mary Douglas we arrive at the idea that there might be, not two, but four basic kinds of engineering culture (cf. Douglas,1973,1982).

Let me explain how this rather striking conclusion can be reached. The first step is to notice that the basic options open to anyone in organising their social affairs are limited. They can attend to the boundaries around their group and find them, or try to make them, either strong or weak. They can then structure the social space within the group in a hierarchical or an egalitarian manner. If we assume that extreme, or pure cases, are more stable, or self-reinforcing, than eclectic or mixed structures, this gives us essentially a two-by-two matrix yielding four ideal types.

The same conclusion can be arrived at by another route. Think of the strategies available to us for dealing with strangers. We can embrace strangers, we can exclude them, we can ignore them, or we can assimilate them to existing statuses or roles. To embrace strangers means sustaining a weak boundary around the group, while to exclude them requires a strong inside-outside boundary. Having a pre-existing slot according to which they can be understood and their role defined means having a complex social structure already in place which is sufficiently stable to stand elaboration and growth. Responses to strangers thus etch out the pattern of boundaries around and within the group and the options, of embracing, excluding, ignoring or assimilating, generate four basic structures – arguably the same four as identified above.

The second step in Mary Douglas’s argument is to suggest that our treatment of things is, at least in part, structured by their utility for responding to people. We have seen the principle at work in the large scale in the case of the by-pass engine as a response to market conditions. But the idea can be both deepened and generalized. Perhaps our use of objects, at whatever level of detail, will always be monitored for implications about the treatment of people. Do they leave existing patterns of interaction and deference in tact, or do they subvert them? Do they provide opportunities to control others, or opportunities to evade control? Take some simple examples. A place may be deemed “dangerous” if we don’t want people to go there. Or a thing is not to be moved or changed, because it embodies the rights of some person or group, say the right of ownership or use. Or the introduction of a new practice may render existing expertise irrelevant, and hence existing experts redundant. Put these two ideas together, social interaction as the necessary vehicle and unavoidable medium for the use of things, and the limited patterns of such interactions, and we may have a basis for a simple typology of cultures or styles in the employment of natural things and processes. We may even have a basis for a typology of styles of engineering.

Whatever your reaction to this idea, I hope you will agree that we badly need intellectual resources with which to think about such difficult themes. That is why I should like to hear a lot more about the sociology of Pratt and Whitney and General Electric, and a lot more from Prof. Suppe and Prof. Vincenti about the groups with whom they worked. How strong were the boundaries between the inside and the outside of the group? Did members of the group readily work with those outside it, trading ideas and information? How hierarchical or internally structured was the inside of the group? Did people swap roles or was the division of labor clear cut? Did they eat and relax together as well as work together? Who and how many were the isolates or outcasts -1 mean: those who were considered unreliable, incompetent or downright dangerous? These are the questions that Mary Douglas wants us to ask.

They may shed light on why some parts of a design are held stable while others are changed, or why a problem may be deemed solved by one group while another treats that solution as an unsatisfying expedient.

I say that these ideas may provide the basis of a typology. There are many ways of criticizing the line of thought I have just sketched. But I would ask you not to be too critical too soon. Give the idea time to settle. It may start generating connections that are not at first obvious to you. For example, Prof. Bilstein’s account of the international heritage of American aerospace technology connects with what I have just said about responses to strangers. He is telling us about a segment of culture that was eager to embrace strangers, where ‘stranger’ here means experts and outsiders from Europe. The European input is sometimes retrospectively edited out, but in practice and despite difficulties, it was seen as a source of opportunity rather than threat.

Or consider the “ways of thinking” alluded to by Prof. Vincenti. Here too we are dealing with questions of group culture and group boundaries. His first-hand account describes the problems of understanding an aerofoil in the transonic region. Two different groups of people had reason to address this issue: those designing wings, and those who worked on propellers. Those who work on wings routinely use the categories of ‘lift’, ‘center of lift’ and ‘drag’, but this is not exactly how the designers of axial turbines and compressors think: “because the airfoil-like blades of their machines operate in close proximity to one another, [they] think of the forces on them rather differently” (p.23). If NACA had structured its research sections differently and with different boundaries from those which actually obtained, might Prof. Vincenti’s group have had a different composition, and could that have enabled them to think about the forces on their wings “rather differently”? Or, to put the point another way, what would have happened if propeller and wing theorists had switched roles? Would the same understanding have emerged, or would they, like the teams at Boeing, Douglas and Vega, have made subtly different artifacts? These are enormously difficult questions that we may never be able to answer in a fully satisfactory way. The need to think counterfactually may defeat even the most well – informed analyst, but these, surely, are the ultimate questions that we cannot avoid addressing.

There is one misunderstanding that I should warn you against. Theories such as Douglas’s tend to be seen, by critics, in terms of stereotypes. The stereotype has them saying that “everything is social” or that “the only causes of belief are social.” Douglas’s approach is not of this kind at all. Society is not the only cause, just as it was not the only cause at work in the episode when the tail-sections from different factories would not fit together. We must also remember that certain large-scale pieces of equipment such as wind tunnels (or great radio telescopes or particle accelerators) have a way of so imposing themselves on their users that they actually generate a characteristic social structure. Given certain background conditions, the apparatus itself may be a cause of the social arrangements. This is compatible with what Douglas is saying. Her ideas would still come into play. The point would be this: suppose people have to queue up to use such things as wind tunnels, radio telescopes and accelerators. If so, there has to be a decision about who comes first, and how long they can have for their experiment. Things have to be planned in advance, timetables have to be drawn up and respected. These are all matters which presuppose a clear structure of authority. Someone must have the power to do this. These are not, perhaps, easy environments for the individualist. Having said that the physical form of the apparatus can be a cause, it would still be interesting to know what leeway there is here. To what extent is it possible to operate such things as wind tunnels, or huge telescopes, in different ways? And if it is possible, how many different ways are there?

IV

Two papers that I have not yet mentioned seem to me to provide a particularly good opportunity for opening up themes bearing on local cultures in engineering or science. The first of them is Prof. Schatzberg’s account of the manufacture of wooden aeroplanes during World War II. The British and Canadians were successful in their continuation of this technology, the Americans had ‘forgotten’ how to do it. Although not presented in these terms, this episode clearly bears on the question of local engineering culture and style. There must have been something about de Havilland which explains why they could and did build in wood and which differentiates them from the American manufacturers, such as Curtiss-Wright, who did not or could not. And presumably there was something equally special about the Canadian firms who were especially keen to get in on the act. Prof. Schatzberg grounds these facts about the culture of firms in the wider culture. He suspects that we need to go to the symbolic meaning of the material under discussion, namely wood. Wood for the Americans meant outmoded tradition; metal meant modernity. Wood for the Canadians meant the mythical heart of their nation, with its great forests. Wood for the British was more neutral, having neither strongly positive nor negative connotations. In that matter-of-fact spirit they built the formidable Mosquito – made of ply and balsa.

Symbolic meanings are not easy to deal with, so it is worth seeing if the argument can be recast in simpler terms. Would it suffice to appeal to, say, vested interests? Canada’s wood was a major economic resource – what better stance to take than to advocate a use and a market for it? Self-interest would dictate nothing less. The American manufacturers had moved on from wood, they had gone all out for metal so as not to be left behind in a competitive market. Who wants to go backwards in a manufacturing technique? It is expensive to re-tool and re-skill. What about de Havilland? They were still building the famous Tiger Moth trainer out of wood, and supplying it in great numbers to the RAF. Even more to the point, as Prof. Schatzberg points out, they could cite their experience with wooden airliners which had important similarities with the Mosquito (p.20). Perhaps economic contingencies such as these are basic, and explain the phenomenon attributed to symbolic meanings. But as Prof. Schatzberg argues, such contingencies often balance out. Canada may be rich in forests, but so was the United States. Canada was no more short of aluminum than the United States. Britain was short of both aluminum and timber and had to import both. As for the market, why did it lead manufacturers to metal in America but not in Britain? Why was demand differently structured in the two cases? That points to a difference of underlying disposition. Perhaps the presence and operation of such dispositions can be illuminated by the idea of symbolic meaning. But whatever our thoughts about the relation of symbolic meanings to interests, Prof. Schatzberg’s intriguing study raises important questions. How local are local engineering cultures, and to what extent do they depend on the wider society?

V

I now want to focus on Prof. Hashimoto’s paper. You will recall that this deals with the work of Leonard Bairstow and his team at the Natural Physical Laboratory in Teddington during and after World War I. We are told of their problematic relation both to PrandtTs school in Gottingen and the (mostly) Cambridge scientists who worked at the Royal Aircraft Establishment in Famborough. Bairstow worked with models in a wind tunnel. He had made his reputation with important studies of the stability of aircraft. Divergences then began to appear between the results of the wind tunnel work and those of the Famborough people testing the performance of real aircraft in the air. Bairstow took the view that his wind tunnel models gave the correct result and the full scale testing was producing flawed and erroneous claims.

Prof. Hashimoto’s account is a clear and convincing example of an interest explanation of the kind I have spoken about. Bairstow and his team had invested enormous effort into the wind tunnel work. Reputations depended on it. Is it any wonder, when it comes to the subtle matter of exercising judgement and assessing probabilities, that Bairstow should be influenced by the time and effort put into his particular approach? Notice I say “influenced” rather than “biased”. I don’t think that there is any evidence in the paper that Bairstow was operating on anything other than the rational plane. He seems to have been a forceful controversialist, but those arguing on the other side had their vested interests as well. Time, energy, skill, and not a little courage, had gone into their results too. Rational persons acting in good faith can and do differ, sometimes radically. To my mind the only questionable note in Prof. Hashimoto’s analysis is when a negative evaluation of Bairstow creeps into the historical description. I suspect that the analysis goes through as well without it.

Bairstow did not just argue in defense of his wind tunnel work on models. He also held out against Prandtl’s “boundary layer” concept. This stance seems to me even more intriguing than his opposition to scale effects. If I understand the matter rightly, Prandtl’s idea of a boundary layer functioned as a justification for certain processes of approximation and simplification which made the treatment of the flow round an aerofoil mathematically tractable. For example, it allowed the problem to be divided into two parts. Bairstow’s opposition seems to have centered on his suspicion of these mathematical expedients. His obituarist, in the Biographical

Memoirs of Fellows of the Royal Society (Temple, 1965 ), suggested that Bairstow didn’t want a simplified or approximate solution to the Navier-Stokes equation for viscous flow, but a full and rigorous solution for the whole mass of fluid. He tried to produce such a treatment, but with only limited success (p.25). So again we are dealing with a matter of scientific judgement on Bairstow’s part. His response to Prandtl was not foolish or dogmatic, but a rational expression of a particular set of priorities and intellectual values. I should like to know where these priorities came from, and if they can be explained.

At first sight it seems odd that a person such as Bairstow, who placed so much weight on the experimental observation of models in wind tunnels, should incline to a mathematically rigorous and complete solution to the equations of flow. We might expect an experimentalist to embrace any clever expedient that would get a plausible answer, even at the cost of a certain eclecticism. So there is a puzzle here. Of course, it may be that we are dealing with nothing but a psychological idiosyncrasy of Bairstow as an individual, but we should at least explore other possibilities. If his strategy commanded the respect of some portion of the scientific community then we are certainly dealing with more than idiosyncrasy. I have already suggested that large installations, like wind tunnels, may demand or encourage clear-cut social organisation and hierarchy. Could it be that living with the demand for rigorous and extensive social accountability lends credibility to the demand for a correspondingly rigorous and general form of scientific accountability? Or is the issue one of insiders and outsiders, of the boundary round the group? If there were a body of existing mathematical techniques which had always sufficed in the past then why import potentially disruptive novelty from the outside? Here we see the relevance of Mary Douglas’s observations about strategies for dealing with strangers. What she says about ways of dealing with novel persons applies on the cognitive plane too. Typically, dealing with new ideas means dealing with new people. A disinclination to do the latter might explain a disinclination to do the former. Clearly all this is speculation on my part. It is no more than a stab in the dark. But however wrong the suggestions might be, I think that this is the area where the argument can be developed.

Interest explanations, it seems, are ubiquitous, and beginning with Prof. Galison and ending with Prof. Hashimoto, we have seen how naturally the different contributors have had recourse to them here. Nevertheless, there is a great deal that we do not yet understand about the operation of interests. For example, the trade-off between long term and short term interests is little understood, though they often incline us to quite different courses of action. Prof. Deborah Douglas’s account, of the relation between engineers and architects, suggests that at first these two groups felt they were in competition with one another. In the event they reached a working relationship, seeing the advantages of co-operation rather than conflict. Prof. Jakab describes how the drying up of government contracts, in 1919, led to a change in the relation between the Engineering Division at McCook Field and the private manufacturers of aircraft. After a period of plenty, a divergence of interests came to the fore and set the stage for a decade of bickering. In offering an interest analysis, then, we are not dealing with a static and unchanging set of oppositions, but a potentially flexible and evolving system of self-understanding. Critics of interest explanations, and there are many of them, often assume they are static and forget that change and flexibility are actually inherent to this manner of explanation.

VI

A further theme I could have pursued is brought out with great clarity in Prof. Anderson’s paper (a paper which, for non-specialists such as myself, was invaluable for introducing some of the basic ideas in aerodynamics). Prof. Anderson’s theme was the coming together of academic or ‘pure’ science with the needs of the practical engineer, and the synthesis of a new form of knowledge that might be called ‘engineering science’. There is a temptation, amongst intellectuals, to treat theory as higher, or more profound, than practice. Practice is the application of theory so, (we might be tempted to conclude) behind every practice there must lurk a theory. In opposition to this, Prof. Anderson reminds us of the post hoc character of the circulation theory of lift. Similarly, with regard to drag, the theoretical explanation of just why engine cowling was so effective came well after the practical innovation itself. There is a whole epistemology to be built by insisting that practice can, and frequently does, have priority over theory. That epistemology will be the one needed to understand the history of aviation and the science of aeronautics. The theme of the priority of the empirical is also made explicit at the end of Prof. Suppe’s paper which tells us about the growth of instrumentation in the history of flight testing. He argues for the significance of this site as a source of new ideas to revivify the philosophy of science. That discipline has, arguably, been too closely linked with the academic laboratory, or at least, with the image of scientific work as theory testing. Prof. Suppe takes us out of the laboratory into the hanger, where the price of failure is far greater than the disappointment of a refuted theory. The aim is to discern useful patterns in the mass of data produced by probes and gauges, it is to root out systematic error, and to find the trick of making signals stand out from noise. Again, there are no rules and no absolute guarantees. Even, or perhaps especially, in these practical fields, reality cannot speak directly to those who want and need to act with the maximum of realism.

If we were looking for a philosophical standpoint that does justice to the practical character of knowledge, for an epistemology for the engineer or aviator, where might we look? I can think of two sources that would be worth exploring, though both suggestions may seem a little surprising. First we could follow the lead of Hyman Levy. Levy was professor of mathematics at Imperial College, London, and had written one of the early textbooks in aeronautics, Cowley and Levy (1918). His theoretical work in fluid mechanics linked him with Bairstow, and he had worked in this field at the National Physical Laboratory. Levy wanted to understand his science philosophically and to develop a philosophy appropriate for “modem man”. He was also a Marxist and belonged to that impressive band of left-wing scientists in Britain in the inter-war years which included J. D. Bernal, Lancelot Hogben, J. B.S. Haldane, and Joseph Needham [see Werskey (1988)]. They did much to spread the scientific attitude and to educate the public about the potential and importance of science. As a Marxist, Levy accepted the laws of dialectical materialism, one of which is the law of the unity of theory and practice. In his Modern Science. A Study of Physical Science in the World Today; published in 1939, Levy devoted a chapter to ‘The Unity of Theory and Experiment.’ He did not here talk in the language of philosophical Marxism, but about wind tunnels and the measurement of lift and drag. His exemplar of the unity of theory and practice was aeronautical research. This might commend itself to Prof. Anderson and Prof. Suppe. But I can also think of another source of philosophical inspiration, one coming from what, at first sight, appears to be the opposite ideological direction. For a philosophy which grounds theory in practice, and meaning in use, we could hardly do better than to consult Wittgenstein’s Philosophical Investigations (1953) and his Remarks on the Foundations of Mathematics (1956). The formalistic concern with theory testing that, as Prof. Suppe observes, limits so much academic philosophy, is wholly absent from Wittgenstein’s work. Perhaps it is no coincidence that Wittgenstein was trained as an engineer and did research on propeller blades. The young Wittgenstein once asked Bertrand Russell if he (Wittgenstein) was any good at philosophy. Wittgenstein’s reason for asking was that if he was no good he intended to become an aviator.1 [3] 1909 they set up the Advisory Committee for Aeronautics under the eminent Cambridge physicist Lord Rayleigh, and dedicated a section of the National Physical Laboratory to aeronautical questions. Prof. Schatzberg reminds us that such facts stand in opposition to many a political lament about Britain’s national decline and lack of industrial spirit. But can this rapid response really have come from a culture that was (as the stereotype has it) dominated by an anti-technological elite steeped in the classics?2

As the papers in this collection make amply clear, the history of aviation as a field of study is rich and many-faceted. There is material enough here to prompt major, and exciting, revisions in the history of culture – as well as in the theory of scientific and technical knowledge.

[1]

P. Galison and A. Roland (eds.), Atmospheric Flight in the Twentieth Century; vii-xvi © 2000 Kluwer Academic Publishers.

ACADEMIC SCIENCE DISCOVERS THE AIRPLANE

Between 1891 and 1896, Otto Lilienthal in Germany made over 2000 successful glider flights. His work was timed perfectly with the rise of photography and the printing industry. In 1871 the dry-plate negative was invented, which by 1890 could freeze a moving object without a blur. Also, the successful halftone method of printing had been developed. As a result, photos of Lilienthal’s flights were widely distributed, and his exploits frequently described in periodicals throughout Europe and the US.

These flights caught the attention of Nikolay Joukowski (Zhukovsky) in Russia. Joukowski was head of the Department of Mechanics at Moscow University when he visited Lilienthal in Berlin in 1895. Very impressed with what he saw, Joukowski bought a glider from Lilienthal, one of only eight that Lilienthal ever managed to sell to the public. Joukowski took this glider back to his colleagues and students in Moscow, put it on display, and vigorously examined it. This is the first time that a university-educated mathematician and scientist, and especially one of some repute, had become closely connected with a real flying machine, literally getting his hands on such a machine. Joukowski did not stop there. He was now motivated about flight – he had actually seen Lilienthal flying. The idea of getting up in the air was no longer so fanciful – it was real. With that, Joukowski turned his scholarly attention to the examination of the dynamics and aerodynamics of flight on a theoretical, mathematical basis. In particular, he directed his efforts towards the calculation of lift. He envisioned bound vortices fixed to the surface of the airfoil along with the resulting circulation that somehow must be related to the lifting action of the airfoil.

Finally, in 1906 he published two notes, one in Russian and the other in French, in two rather obscure Russian journals. In these notes he derived and used the following relation for the calculation of lift (per unit span) for an airfoil:

L = pVT

where L is the lift, p is the air density, V is the velocity of the air relative to the airfoil, and Г is the circulation, a technically-defined quantity equal to the line integral of the flow velocity taken around any closed curve encompassing the airfoil (Circulation has physical significance as well. The streamline flow over an airfoil can be visualized as the superposition of a uniform freestream flow and a circulatory flow; this circulatory flow component is the circulation. Figure 1 is a schematic illustrating the concept of circulation.) With this equation, Joukowski revolutionized theoretical aerodynamics. For the first time it allowed the calculation of lift on an airfoil with mathematical exactness. This equation has come down through the twentieth-century labeled as the Kutta-Joukowski Theorem. It is still taught today in university-level aerodynamics courses, and is still used to calculate lift for airfoils in low-speed flows.

The label of this theorem is shared with the name of Wilhelm Kutta, who wrote a Ph. D. dissertation on the subject of aerodynamic lift in 1902 at the University of Munich. Like Joukowski, Kutta was motivated by the flying success of Lilienthal. In particular, Kutta knew that Lilienthal had used a cambered airfoil for his gliders, and that, when cambered airfoils were put at a zero angle of attack to the freestream, positive lift was still produced. This lift generation at zero angle of attack was counter-intuitive to many mathematicians and scientists at that time, but experimental data unmistakenly showed it to be a fact. Such a mystery made the theoretical calculation of lift on a cambered airfoil an excellent research topic at the time – one that Kutta readily took on. By the time he finished his dissertation in 1902, Kutta had made the first mathematical calculations of lift on cambered airfoils. Kutta’s results were derived without recourse to the concept of circulation.

ACADEMIC SCIENCE DISCOVERS THE AIRPLANE

Figure 1. The synthesis of the flow over an airfoil by the superposition of a uniform flow and a circulatory flow.

Only after Joukowski published his equation in 1906 did Kutta show in hindsight that the essence of the equation was buried in his 1902 dissertation. For this reason, the equation bears the name, the Kutta-Joukowski Theorem.

This equation became the quantitative basis for the circulation theory of lift. For the first time a mathematical and scientific understanding of the generation of lift was obtained. The development of the circulation theory of lift was the first major element of the evolution of aerodynamics in the twentieth century, and it was in the realm of science. The objective of Kutta and Joukowski – both part of the academic community – was understanding the nature of lift, and obtaining some quantitative ability to predict lift. Their work was not motivated, at least at first, by the desire to design a wing or airfoil. Indeed, by 1906 wings and airfoils had already been designed and were actually flying on piloted machines, and these designs were accomplished without the benefit of science. The circulation theory of lift was created after the fact.

Contemporary with the advent of the circulation theory of lift was an equally if not more important intellectual breakthrough in the understanding and prediction of aerodynamic drag. The main concern about the prediction of lift on a body inclined at some angle to a flow surfaced in the nineteenth-century, beginning with George Cayley’s concept of generating a sustained force on a fixed wing. In contrast, concern over drag goes all the way back to ancient Greek science. The retarding force on a projectile hurtling through the air has been a major concern for millenniums. Therefore, it is somewhat ironic that the breakthroughs in the theoretical prediction of both drag and lift came at almost precisely the same time, independent of how long the two problems had been investigated.

What allowed the breakthrough in drag was the origin of the concept of the boundary layer. In 1904, a young German engineer who had just accepted the position as professor of applied mechanics at Gottingen University, gave a paper at the Third International Mathematical Congress at Heidelberg that was to revolutionize aerodynamics.7 Only eight pages long, it was to prove to be one of the most important fluid dynamics papers in history. In it, Prandtl described the following concept. He theorized that the effect of friction was to cause the fluid immediately adjacent to the surface to stick to the surface, and that the effect of friction was felt only in the near vicinity of the surface, i. e., within a thin region which he called the boundary layer. Outside the boundary layer, the flow was essentially uninfluenced by friction, i. e., it was the inviscid, potential flow that had been studied for the past two centuries. This conceptual division of the flow around a body into two regions, the thin viscous boundary layer adjacent to the body’s surface, and the inviscid, potential flow external to the boundary layer (as shown in Figure 2), suddenly made the theoretical analysis of the flow much more tractable. Prandtl explained how skin friction at the surface could be fundamentally understood and calculated. He also showed how the boundary layer concept explained the occurrence of flow separation from the body surface – a vital concept in the overall understanding of drag. Since 1904, many aerodynamicists have spent their lives studying boundary-layer phenomena – it is still a viable area of research

today. This author dares to suggest that PrandtTs boundary layer concept was a contribution to science of Nobel prize stature. Perhaps one of the best accolades for Prandtl’s paper was given by the noted fluid dynamicist Sydney Goldstein who was moved to state in 1969 that: “The paper will certainly prove to be one of the most extraordinary papers of this century, and probably of many centuries.”8

As in the case of Kutta and Joukowski, Prandtl was a respected member of the academic community, and with the boundary layer concept he made a substantial scientific contribution to aerodynamics. This was science; the boundary layer concept was an intellectual model with which Prandtl explained some of the fundamental aspects of a viscous flow. However, within a few years this concept was being applied to the calculations of drag on simple bodies by some of PrandtTs students at Gottingen, and by the 1920s, research on boundary layers had become focused on acquiring knowledge for the specific purpose of drag calculations on airfoils, wings, and complete airplanes. That is, boundary layer theory became more of an engineering science.

In retrospect the beginning of the twentieth-century was the time of major technological breakthroughs in theoretical aerodynamics. These events heralded another breakthrough – one of almost a sociological nature. Wilhelm Kutta, Nikolay Joukowski, Ludwig Prandtl were all university-educated with Ph. D.s in the mathematical, physical, and/or engineering sciences and all conducted aerodynamic research focused directly on the understanding of heavier-than-air flight. This represents the first time when very respected academicians embraced the flying machine; indeed, the research challenges associated with such machines absolutely dictated the direction of their research. Kutta, Joukowski, and Prandtl were very much taken by the airplane. What a contrast with the prior century, when respected academicians essentially eschewed any association with flying machines, thus

ACADEMIC SCIENCE DISCOVERS THE AIRPLANE

Figure 2. PrandtTs concept of the division of the flow field into two regions: (1) the thin viscous boundary layer adjacent to the body surface, and (2) the inviscid (frictionless) flow outside the boundary layer.

causing a huge technology transfer gap between nineteenth-century science and the advancement of powered flight.

What made the difference? The answer rests in that of another question, namely, who made the difference? The answer is Lilienthal and the Wright brothers. Otto LilienthaTs successful glider flights were visual evidence of the impending success of manned flight; we have seen how the interest of both Kutta and Joukowski was motivated by watching Lilienthal winging through the air, as seen either via photographs or by actual observation. And when the news of Wilbur’s and Orville’s success with the Wright Flyer in 1903 gradually became known, there was no longer any doubt that the flying machine was a reality. Suddenly, work on aeronautics was no longer viewed as the realm of misguided dreamers and madmen; rather it opened the floodgates to a new world of research problems, to which twentieth-century academicians have flocked. After this, the technology transfer gap, in the sense that occurred over the previous centuries, began to grow smaller.