In 1987, a Washington Post headline read, "The aircraft engine of the future has propellers on it."¹ To many this statement was something like heralding "the reincarnation of silent movies."² Why would an "old technology" ever be chosen over a modem, new, advanced alternative? How could propeller technology ever supplant the turbojet revolution? How could the 'Jet set mind-set" of corporate executives, who demanded the prestige of speed and "image and status with a Jet," ever be satisfied with a slow, noisy, propeller-driven aircraft? ³ A Washington Times correspondent predicted that the turbojet would not be the propulsion system of the future. Instead, the future would witness more propellers than Jets and if "Star Wars hero Luke Skywalker ever became chairman of a Fortune 500 company, he would replace the corporate jet with a ... turboprop."⁴ It appeared that a turboprop revolution was underway.

NASA Lewis Research Center's Advanced Turboprop Project (1976-1987) was the source of this optimism. The energy crisis of the early 1970s served as the catalyst for renewed government interest in aeronautics and NASA launched this ambitious project to return to fuel saving, propeller-driven aircraft. The Arab oil embargo brought difficult times to all of America, but the airlines industry, in particular, suffered and feared for its future in the wake of a steep rise in fuel prices. NASA responded to these fears by creating a program to improve aircraft fuel efficiency. Of the six projects NASA funded through this program, the Advanced Turboprop Project promised the greatest payoffs in terms of fuel savings, but it was also the most conceptually radical and technically demanding.

The project began in the early 1970s with the collaboration of two engineers, Daniel Mikkelson from NASA Lewis, and Carl Rohrbach of Hamilton Standard, the nation's last major propeller manufacturer. Mikkelson, then a young aeronautical research engineer, went back to the old NACA wind tunnel reports where he found a "glimmer of hope" that propellers could be redesigned to make propeller-powered aircraft fly faster and higher than those of the mid to late-1950s.⁵ Mikkelson and Rohrbach came up with the concept of sweeping the propeller blades to reduce noise and increase efficiency and NASA received a joint patent with Hamilton Standard for the development of this technology. At Lewis, Mikkelson sparked the interest of a small cadre of engineers and managers. They solved key technical problems essential for the creation of the turboprop, while at the same time they attracted support for the project. After a project office was established, they became political advocates, using technical gains and increasing acceptance to fight for continued funding. This involved winning government, industry, and public support

An advanced propeller swirl recovery model is shown in the NASA Lewis Research Centers 8 x 6 foot supersonic wind tunnel. Propeller efficiencies and noise are measured at cruise much numbers up to 0. 80 and at takeoff and approach conditions. Vane pitch angles and propfan-to-vane axial spacings are varied. The testing was part of the Advanced Turboprop Project, with the goal of providing the technology base to enable the U.S. development of quieter, fuel efficient turboprop engines with a comfortable aircraft interior environment. (NASA photo no. 90-H-78).

for the new propeller technology. Initially the project involved only Hamilton Standard, but the aircraft engine manufacturers, Pratt & Whitney, Allison, and General Electric, and the giants of the airframe industry, Boeing, Lockheed, and McDonnell Douglas joined the bandwagon as the turboprop appeared to become more and more technically and socialIy feasible. The turboprop project became a large, well-funded, "heterogeneous collection of human and material resources" that contemporary historians refer to as "big science."⁶ At its height it involved over forty industrial contracts, fifteen university grants, and work at the four NASA research centers, Lewis, Langley, Dryden, and Ames. The progress of the advanced turboprop development seemed to foreshadow its future dominance of commercial flight.

The project had four technical stages: "concept development" from 1976 to 1978; "enabling technology" from 1978 to 1980; "large-scale integration" from 1981 to 1987; and finally "flight research" in 1987.⁷ During each of these stages, NASA's engineers confronted and solved specific technical problems that were necessary for the advanced turboprop project to meet the defined government objectives concerning safety, efficiency at high speeds, and environmental protection. NASA Lewis marshaled the resources and support of the United States aeronautical community to bring the development of the new technology to the point of successful flight testing. In 1987, these NASA engineers, along with a wide-ranging industry team, won the coveted Collier Trophy for developing a new fuel efficient turboprop propulsion system.⁸ The winning team included Hamilton Standard, General Electric, Lockheed, the Allison Gas Turbine Division of General Motors, Pratt & Whitney, Rohr Industries, Gulfstream, McDonnell Douglas, and Boeing —certainly the largest, most diverse group, to be so honored in the history of the prize.

Despite this technical success, the predicted turboprop revolution never came, and no commercial or military air fleet replaced their jets with propellers. The reason for this failure was socio-economic, not technical. Throughout the project, social issues influenced and defined the status of the advanced turboprop. From the beginning it was the perception of an energy crisis, not a technological innovation, that spurred the idea of the project itself. The Cold War and the existence of Soviet high-speed turboprops played a key role in convincing Congress to fund the project. As the project progressed, within each technological stage, the engineers used distinctive and creative approaches to deal with the complex web of government, industry, and academic contractors. More often than not, the main question was not does the technology work, but how can we get government, industry, and the public to accept this technology? In the end it was a socioeconomic issue again which shelved the program. The reduction of fuel prices ended the necessity for fuel conservation in the skies and today the advanced turboprop remains a neglected, or "archived" technology.

This is not to imply that the technical achievements were unimportant. Each distinct technical stage of the project determined a corresponding social action. During the concept development stage, creative advocacy was necessary to sell the government and industry on this radical idea. During the enabling technology stage, engineers used complex project management skills to ensure that this massive team would function effectively. During the large-scale integration stage, NASA had to deal with a competitor that surprised them by introducing its own high-speed turboprop. Finally, during the flight research stage, NASA became aware that no current airlines would adopt the advanced turboprop and thus the

engineers waged a battle to win the Collier Trophy to try and gain positive status and recognition for their technical achievement.

The relationship between these technical and social spheres was never either a simplistic story of social construction or technological determinism. Rather, the relationship was one of interdependence. At times the project advanced on its technical merits; at others, it progressed through political persuasion. At each stage, only after NASA engineers and their industrial and academic partners solved both the social and technical problems holding it back, was the advanced turboprop project able to obtain funding and move forward. But ultimately, the socio-economic issue of petroleum price and availability managed to scuttle NASA's technical success.

Thomas Hughes, a prominent historian of technology, has argued that the research and development organizations of the twentieth century, no matter whether they are run by a government, industry, or members of a university community, stifle technical creativity.⁹ In these organizations there can be found "no trace of a flash of genius."¹⁰ In contrast, the late 19th century for Hughes was the "golden era" of invention —a time when the independent inventor flourished without institutional constraints. Recently, David Hounshell has challenged Hughes's contention that industrial research laboratories "exploit creative, inventive geniuses; they neither produce nor nurture them."¹¹ Not only can the industrial research laboratory nurture a creative individual, but collectively, people engaged in research and development contribute to making an invention a commercial reality. In his study of the organization of research at Du Pont, Hounshell paid tribute to the individual brilliance of the organic chemist Wallace H. Carothers, but he argued that the real "genius of nylon was in the organization that developed it into one of the most successful and profitable materials of the twentieth century."¹² In our view, the NASA Advanced Turboprop Project represents another case in which organizational capabilities, not individual genius alone, create the opportunity for significant innovation. The organization that supported the development of the turboprop was far more complex than the research laboratory of an industrial firm, yet it responded to the energy crisis to advance a radical idea. As Donald Nored, who headed the office at NASA Levis Research Center that managed the three aircraft energy efficiency projects remarked, "The climate made people do things that normally they'd be too conservative to do."¹³ The history of the advanced turboprop demonstrates how a radical innovation can emerge from a dense, conservative web of bureaucracy to nearly revolutionize the world's aircraft propulsion systems.

Although NASA won several Collier trophies for innovations related to the space program, it had produced no winners in aeronautics since the founding of the agency in 1958. NASA's predecessor organization, the National Advisory Committee for Aeronautics (NACA), had received five Collier trophies for contributions to aeronautics between 1929 and 1958. These trophies paid tribute to the individual creativity and the unique research environment of the NACA's research laboratories. James R. Hansen has described in this volume how engineer Fred E. Weick used the NACA's unique wind tunnel facilities to develop

the NACA low-drag cowling. Succeeding Collier trophies awarded under the institutional aegis of the NACA followed a similar pattern. Lewis A. Rodert won it for developing a thermal ice prevention system for aircraft (see the essay by Glenn E. Bugos, this volume), John Stack won it twice for his contributions to supersonic theory and the development of the transonic wind tunnel, and Richard Whitcomb carried off the prize for his discovery and empirical validation of the area rule. What made the award garnered by the NASA/industry team in 1987 different was that it recognized the collective talents of government engineers from four NASA research centers, academic researchers, and contractors from the propeller, engine, airframe, and airline industries.

The history of the turboprop project is interesting from an institutional standpoint because it took root and flourished within NASA's conservative, bureaucratic environment. It was modeled, not on NASA's small-scale aeronautical research projects (typically carried on by former NACA laboratories), but on the large-scale projects of the space program. The NASA Lewis Research Center adopted an administratively complex team approach that depended on input not simply from other NASA Centers, but also from numerous industrial and university contractors. Essentially, NASA Lewis Research Center became the center of an extensive government-industry-academic complex. At each stage in the project, the management team determined what needed to be done and sought the appropriate help both from within and outside NASA.

With its expertise in propulsion technology, the NASA Lewis Research Center was ideally suited to manage the turboprop project. Set up in Cleveland, Ohio, during World War II as an aircraft engine research laboratory, Lewis became the third laboratory of the National Advisory Committee for Aeronautics. Lewis engineers pursued aircraft engine research in the national interest—often over the objection of the engine companies who perceived the government as interfering with the normal forces of supply and demand. During the early years of the Cold War, the laboratory participated in engine research and testing to assist the engine companies in developing the turbojet engine. After the launch of Sputnik, the laboratory focused on a new national priority-rocket propulsion research and development. Almost all work on air-breathing engines ceased for nearly ten years.

The return to aircraft engine research coincided with drastic reductions in staff, mandated by cuts in NASA's large-scale space programs.¹⁴ The mass exodus of nearly 800 personnel in 1972 sparked an effort to redefine the center's mission and find new sources of funding. The following year, OPEC's oil embargo galvanized the Center's director, Bruce Lundin, to look for ways to use its propulsion expertise to help solve the energy crisis. In 1974, Lewis received $1.5 million for a wind-energy program from the National Science Foundation and the Energy Research and Development Administration (ERDA). A program in solar cell technology development followed on its heels with increasing funding of various energy-related programs by ERDA and its successor, the Department of Energy. The changing focus of the Center's activities prompted rumors-emphatically denied-that it would become part of ERDA. The new emphasis on energy efficient aircraft, unlike the ERDA projects, promised to keep Lewis strongly in NASA's fold.¹⁵ Moreover, it brought high visibility to the aeronautics side of NASA, long overshadowed by the enormous budgets and prestige of the space program.

Although it shared similarities in management with NASA's space projects, the turboprop project differed in significant ways. First, although the advanced turboprop was the reincarnation of an old idea, it involved the creation of cutting-edge technology. Space

projects involved rigorous oversight, but generally relied on existing technology. When necessary, NASA contracted with industry to produce whatever new technology was needed for a particular mission. The turboprop project tapped the creative talents of engineers at NASA in ways that were reminiscent of the NACA tradition of in-house research, though in management scope it transcended the narrow institutional boundaries of NASA's research centers. Second, though all NASA projects of the early 1970s needed to be "sold" to an increasingly tight-fisted Congress, the controversial nature of the turboprop meant that NASA Lewis had to build support both at Headquarters and within the aviation community. What NASA referred to as "advocacy" needed to be vigorous and continuous throughout the life of the project.

The OPEC oil embargo of 1973 awakened the United States to the degree of control outside nations had over the lives of every American. The increased price of oil affected all areas of the economy, but none more than the airlines industry.¹⁶ Earl Cook, noted geographer and geologist, has argued, "Whoever controls the energy systems can dominate the society." ¹⁷ An extension of this argument is, whoever possesses the fuel supply controls the energy systems. Five sources of energy, including petroleum, natural gas, coal, hydropower, and nuclear, accounted for all fuel consumption in the United States during 1973. Of these five sources, America was most dependent upon petroleum, consuming approximately seventeen million barrels of oil a day.¹⁸ At no other time in American history was Cook's aphorism more evident than in 1973 when the United States imported six million barrels of oil a day, 64 percent of which came from the Organization of Petroleum Exporting Countries (OPEC).¹⁹ The concern in the United States was that since OPEC controlled the petroleum, could they dominate American society?

In response to the energy crisis, in 1973 the airlines industry initiated its own fuel-saving program which reduced fuel consumption by over one billion gallons per year.²⁰ But these measures were not enough. jet fuel prices jumped from twelve cents to over one dollar per gallon and total yearly fuel expenditures increased by one billion dollars, or triple the earnings of the airlines. Prior to 1972, fuel accounted for one-quarter of the commercial airlines' total direct operating costs.²¹ During the crisis, fuel represented over half of the airlines' operating costs. The result was a reduction in the number of flights, the grounding of some aircraft, and the "furloughing" of some 10,000 employees. If the situation in the early 1970s seemed bad, prospects for the future appeared even worse. Linking the fate of the airlines, the cost of jet fuel and the prosperity of the nation as a whole, airlines industry lobbyists rushed to their congressmen. The politicians, in turn, appealed to NASA.

Why was jet fuel so important to our national interest? Clifton F. Von Kann, senior vicepresident of the Air Transport Association of America, pointed out in a 1975 Senate statement that airlines were "more than just another means of transportation ."²² He asserted they played a major part in the economic and military success of the nation. They also

provided the infrastructure for the mail system, the national export system, and the $60 billion tourist industry. jet fuel was the "life-blood" of the airlines, but it was also their Achilles heel. He warned a failure to control the rising cost of fuel might result in either the nationalization or the withering away of the "basic building block in the structure of the U.S. economy."²³ Senator Barry Goldwater linked this crisis to the possible "loss of a large part of our world supremacy."²⁴ The fuel crisis created an opportunity for NASA at a time when Congress had drastically cut funding for the space program. Aeronautics, the first "A" in NASA, had long taken a back seat to the spectacular space missions of the Apollo years. Now the agency was ready to reassert its role as the nation's premier institution for research and development in civil aeronautics.

In January 1975, James Fletcher, the NASA Administrator, received a letter from Senators Barry Goldwater and Frank Moss. ²⁵ The letter suggested a massive technology project involving NASA and industry to help ease the burden on the airlines caused by the energy crisis. Its goal was the realization of a new generation of fuel-efficient aircraft. Goldwater and Moss asked NASA to propose a plan, develop the technology, and facilitate the "technology transfer process" to industry.²⁶ Technology transfer later became a particularly thorny issue in the debate over whether the government should carry development to the point of costly flight testing, or leave that phase to the manufacturers who stood to benefit handsomely from this government-generated technology.
In February 1975, NASA formed the Intercenter Aircraft Fuel Conservation Technology Task Force to explore all potential options .²⁷ Sixteen government scientists and engineers from NASA, the Department of Transportation, the Federal Aviation Administration, and the Department of Defense took part in the seven-month study. ²⁸ James Kramer, the task force leader, called for any new ideas that would satisfy government criteria, even those that might be considered "unusual." The task force defined six major areas with the potential for significant impact on aircraft fuel efficiency. It recommended the creation within NASA of the Aircraft Energy Efficiency (ACEE) Program, the administrative umbrella for six new aeronautics projects —three related to the airframe and three to the propulsion system.²⁹

NASA assigned management of the three propulsion projects to the NASA Lewis Research Center. The first of these propulsion projects focused on improving existing turbofan engines through the redesign of selected engine components. It was the least technically challenging of the three projects and aimed for a five percent increase in fuel efficiency within a few years. The second project, the Energy Efficient Engine (E³), involved building 11 a brand new engine from scratch" and offered a far greater payoff —an increase in fuel efficiency of ten to fifteen percent. In essence, NASA proposed to assume the risk for developing an "all new technology in an all up engine."³⁰ With a new "recoupment program" in place, the government expected to get back some of its investment out of the profits of the engine manufacturers, General Electric and Pratt & Whitney.

In contrast to these two relatively conservative projects, the advanced turboprop offered dramatic increases in fuel efficiency. NASA planners believed that an advanced turboprop could reduce fuel consumption by twenty to thirty percent over existing turbofan engines with comparable performance and passenger comfort at speeds up to Mach 0.8 and altitudes up to 30,000 feet. (It should be noted that commuter turboprop-powered aircraft in current use fly at far slower speeds and lower altitudes.) The ambitious goals of the turboprop project made it controversial and challenging both from a technical and social point of view. Technically, studies by Boeing, McDonnell Douglas, and Lockheed pointed to four areas of concern: propeller efficiency at cruise speeds, both internal and external noise problems, installation aerodynamics, and maintenance costs.³¹ Socially, the turboprop also presented daunting problems. Because of the "perception of turboprops as an old-fashioned, troublesome device with no passenger appeal," the task force report noted, "the airlines and the manufacturers have little motivation to work on this engine type."³² Clifton Von Kann succinctly summed up these concerns to Barry Goldwater during his Senate testimony when he said that of all the proposed projects, "the propeller is the real controversial one."³³

What made the government willing to assume the risk for such a difficult project? Proposed fuel savings was one important factor. However, the task force report indicated another significant and related issue —the Soviet Union had a high speed "turboprop which could fly from Moscow to Havana."³⁴ The continuing Cold War prompted the United States to view any Soviet technical breakthrough as a potential threat to American security. During the energy crisis, the knowledge that Soviet turboprop transports had already achieved high propeller fuel efficiency at speeds approaching those of jet-powered planes seemed grave indeed and gave impetus to the NASA program. During the government hearings, NASA representatives displayed several photos of Russian turboprop planes to win congressional backing for the project.³⁵ The Cold War helped to define the turboprop debate. No extensive speculation on the implications of Russian air superiority for American national security seemed necessary. The Soviet Union could not be allowed to maintain technical superiority in an area as vital as aircraft fuel efficiency. Thus, the report included the demanding Advanced Turboprop Project as part of the ten-year, $670 million Aircraft Energy Efficiency Program to improve fuel efficiency.

Industry resistance and NASA Headquarters' sensitivity to the public relations aspect of this opposition were among the key reasons that of the six projects within the Aircraft Energy Efficiency (ACEE) program, only the advanced turboprop failed to receive funding in 1976. John Klineberg, later director of Lewis Research Center, recalled that it was delayed "because it was considered too high risk and too revolutionary to be accepted by the airlines."³⁶

If the advanced turboprop was so important to the national welfare, why did it encounter such opposition from the airframe and aircraft engine manufacturers? Donald Nored, the division chief in charge of the three propulsion projects at Lewis, remarked that his engineering peers in industry were "very conservative and they had to be." They were "against propellers" because they had "completely switched over to jets." Because of their commitment to the turbojet, they continually cited problems that they believed resulted from propellers. This included noise, maintenance, and the fear that the "blades would come apart." Nored recalled each problem had to be "taken up one at a time and dealt with."³⁷ It appears the government's revolutionary vision of the future frightened the aircraft industry with its large investment in turbofan technology. Aircraft structures and engines are improved in slow, conservative, incremental steps. To change the propulsion system of the nation's entire commercial fleet represented an investment of mind-boggling proportions. Even if the government put several hundred million dollars into developing an advanced turboprop, the airframe and aircraft engine industries would still need to invest several billion dollars to commercialize it. Revolutionary change did not come easily to an established industry so vital to the nation's economy.

Turboprop advocates encountered not only the opposition of industry representatives, but the hesitation and timidity of NASA Headquarters. By default, the advocacy role fell to NASA Lewis engineers, though the public relations aspect of technology funding had never been the Cleveland laboratory's strong suit. Lewis had a reputation for being more conservative and technical than the other NASA Centers.³⁸ One Lewis engineer remarked that when other Centers sent five representatives to important meetings, Lewis sent one. Moreover, research engineers from the aeronautics side of NASA had little experience managing major contracts. Yet the energy crisis and the need for projects to sustain the Center's viability within NASA galvanized a small cadre of Lewis engineers into action. They used their technical and new-found managerial creativity to sell NASA Headquarters and industry on a revolutionary new propulsion system —one that might forever ground all existing subsonic turbojets.

Technically, the entire future of the advanced turboprop project initially depended on proving whether a model propfan could achieve the predicted fuel efficiency rates.³⁹ If this model yielded successful results, then project advocates would be able to lobby for increased funding for a large research and development program. Thus, even during its earliest phase, the technical and social aspects of the project worked in tandem.

Lewis project managers awarded a small group of researchers at Lewis and Hamilton Standard a contract for the development of a two-foot diameter model propfan, called the SR-1 or single-rotating propfan. Single-rotating meant that the propfan had only one row of blades, as opposed to a counter-rotating design with two rows of blades, each moving in opposite directions. This model achieved high efficiency rates and provided technical data that the small group of engineers could use as ammunition in the fight to continue the program.

At the same time that they proved the technology using small-scale models, Lewis engineers built a consensus for the project, defending it against objections of skeptical segments of industry and government advisory committees. Advocacy is essentially "marketing" or "selling" to gain government funding and industry backing for new programs like the advanced turboprop. Funding government programs is neither scientific nor entirely rational, but depends on people and how they navigate a complex bureaucracy,

while avoiding numerous political entanglements. During the Apollo years, NASA had what amounted to a blank check to land a human being on the Moon within a decade. Not needing to spend time and energy fighting for funding, engineers had greater freedom to focus on building and testing hardware and managing space missions. But to keep the programs of the 1970s alive, even those that responded to a national crisis, required effort in non-technological spheres of activity.

Lewis was fortunate that Donald Nored, a maestro of project management, played a strong role in building a constituency in support of the project. Unlike most of the other Lewis engineers involved in advanced turboprop development, he hailed from the space side of NASA's house. He had worked on chemical rockets and high power lasers prior to taking up his post as head of the Aircraft Energy Efficiency Program Office at Lewis in 1975. He helped to show aeronautical engineers, more at ease with in-house research, how to negotiate the system to win funding. In 1981, with Frank Berkopec, Nored attempted to demystify the advocacy process by laying down guidelines for others within the Aeronautics Directorate. They disabused their order-seeking engineering colleagues of the notion that advocacy could be compressed into a series of well-defined steps. Rather, they wrote, it is

"basically informal, unstructured, and quite often confusing."⁴⁰ Since only a few of the proposed NASA programs received funding each year, they argued, the advocacy process had become essential and activities related to it should receive a "high priority."⁴¹

The advocacy guidelines indicated that the interactions with "industry, advisory groups, and especially Headquarters will often require rapid, comprehensive, and in-depth respondents [sic] to requests."⁴² One early request of the turboprop project centered on the aircraft industry's concern over the safety of propellers. An aircraft accident advisor raised a question during a meeting of the Industrial Advisory Board at NASA Headquarters concerning the "safety aspect of propellers breaking away from the engine and the damage caused by their impingement into the fuselage."⁴³ Lewis engineers quickly launched their own study into propeller safety and commissioned similar studies at Hamilton Standard and Detroit Diesel Allison. The results were overwhelmingly positive. Lewis examined over 12,000 accident reports from 1973 to 1975 and found no instance where a propeller blade broke away from its engine.⁴⁴ Hamilton Standard reported that after fifty million hours of propeller flight time there had never been an instance of structural failure.⁴⁵ While after twenty million hours, Detroit Diesel Allison found one structural failure; they were quick to point out that "the aircraft landed routinely without further incident and no one was injured in the aircraft or on the ground."⁴⁶ This example typifies not only the early skepticism and resistance by industry to the idea of returning to propeller aircraft but also the "rapid, comprehensive, and in-depth responses" of NASA to industry's concerns. The advocacy process required to "market" and "sell" the radical turboprop project was in full swing. It continued to effectively diffuse the concerns of skeptics.

Successful advocacy brought the formal establishment of the Advanced Turboprop Project in 1978 and initiation of the enabling technology phase. As the lead Center for the project, NASA Lewis had full responsibility for the management of its increasingly far-flung and complicated pieces. Before this phase began, NASA engineers devised a detailed "management approach" and the plan was approved in 1977. Officially, Lewis was to have "responsibility to execute all detailed project planning documentation, develop and implement the procurement of components and systems, provide technical direction to contractors, perform contract administration, perform engineering functions, coordinate the related in-house research and technology programs, and exercise the usual project review reporting and control functions."⁴⁷ These interrelated activities put Lewis in the middle of an intricate web of government (other NASA Centers), industry, and academic contracts. Project managers were responsible for assigning the technology contracts. They also had the equally important function of ensuring that both the public and the government viewed the ATP positively.

Once the management structure was in place, the technology studies could begin. Technically, this phase dealt with four critical problems: modification of propeller aerodynamics, cabin and community noise, installation aerodynamics, and drive systems.⁴⁸ Propeller aerodynamic work included extensive investigations of blade sweep, twist, and thickness. The late 1970s was the first time that engineers used a high speed computer to analyze the design of a propeller. Computers were not yet in widespread use when the turbofan replaced propeller-powered planes in the 1950s. Lewis programmers used their Cray supercomputers to develop the first three-dimensional propeller aerodynamic analysis, A further structural and aerodynamic achievement was to use thinner titanium blades to reduce the flutter problems associated with the steel propeller blades used in the 1940s and 1950s.

The advantage of propellers to save fuel had to be balanced against the potential harm to the environment their noise caused.⁴⁹ New computer-generated design codes not only contributed to improved propeller efficiency, but contributed to solving problems associated with noise. Engineers closely monitored the effect of propeller noise on both cabin occupants and people on the ground. To study propeller acoustics, they mounted propeller models on a JetStar aircraft fuselage at the NASA Dryden facility. Microphones located on the airframe and also on a Learjet chase plane provided data at close range and at a distance. After reviewing the sound pattern data, they concluded that substantial

noise reduction technology was necessary to meet the established goals. Eventually, they achieved a reduction of sixty to sixty-five decibels of noise through a combination of structural advances and flight path modifications.

The final two technical problems of the enabling phase dealt with installation aerodynamics and the drive system. Numerous installation arrangements were possible for mounting the turboprop on the wing. Should the propeller operate by "pushing" or "pulling" the aircraft? How should the propeller, nacelle, and the wing be most effectively integrated to reduce drag and increase fuel efficiency? Wind tunnel tests were able to reduce drag significantly by determining the most advantageous wing placement for the propeller. Engineers also examined various drive train problems, including the gearboxes.

Solutions to all the enabling phase technical problems was still not enough to guarantee the continued funding of the program. Key social questions were still associated with this controversial technology. A vital concern for the advanced turboprop project managers was the social question concerning passengers: how receptive would they be to propeller-driven aircraft? In 1975, a government panel reported that they were "generally opposed to the turboprop aircraft, primarily because they felt that there would be little or no public acceptance." ⁵⁰ If the public would not fly in a turboprop plane, all the potential fuel savings would be lost flying empty planes across the country.

In response to this concern, NASA and United Airlines initiated an in-flight questionnaire to determine customer reaction to propellers. Both NASA and industry were aware of the disastrous consequences for the future of the program if this study found that the public was against the return of propeller planes. As a result, the questionnaire de-emphasized the propeller as old technology and emphasized the turboprop as the continuation and advancement of flight technology. The first page of the survey consisted of a letter from the United Airlines vice president of marketing to the passenger asking for cooperation in a "joint industry-government study concerning the application of new technology to future aircraft."⁵¹ This opening letter did not mention the new turboprops. The turboprop, inconspicuously renamed the "prop-fan" to give it a more positive connotation, did not make its well-disguised appearance until page four of the survey where the passenger is finally told that "'prop-fan' planes could fly as high, as safely, and almost as fast and smooth as jet aircraft." This was a conscious rhetorical shift from the term "propeller" to "prop-fan" to disassociate it in peoples' minds from the old piston engine technology of the pre-jet propulsion era. Brian Rowe, a General Electric vice president with oversight of the advanced propeller projects, explained this new labeling strategy. He said, "They're not propellers. They're fans. People felt that modern was fans, and old technology was propellers. So now we've got this modern propeller which we want to call a fan."⁵² The questionnaire explained to the passenger that not only did the "'prop-fans' ... look more like fan blades than propellers," they would also use twenty to thirty percent less fuel than jet aircraft.

The questionnaire then displayed three sketches of planes-two were propeller driven and the third was a turbofan. The passenger had to choose which one he or she would "prefer to travel in." Despite all the planes being in-flight, the sketches depicted the propellers as simple circles (no blades present), while the individual blades of the turbofan were visible. These were all subtle and effective hints to the passenger that the "prop-fan" was nothing new and that they were already flying in planes powered by engines with fan blades.

Not surprisingly, the survey yielded favorable results for the turboprop. Of 4,069 passengers surveyed, fifty percent said that they "would fly prop-fan," thirty-eight percent had "no preference," and only twelve percent preferred a jet.⁵³ If the airlines could avoid fare increases due to the implementation of the turboprop, eighty-seven percent of the respondents stated they would prefer to fly in the new turboprop. Relieved and buoyed by the results, NASA engineers liked to point out that most of the passengers did not even know what propulsion system was currently on the wing of their aircraft.⁵⁴ According to Mikkelson, all the passengers wanted to know was "how much were the drinks, and how much was the ticket."⁵⁵ Equally relieved was Robert Collins, vice president of engineering for United Airlines, who concluded that this "carefully constructed passenger survey ... indicated that a prop-fan with equivalent passenger comfort levels would not be negatively viewed, especially if it were recognized for its efficiency in reducing fuel consumption and holding fares down."⁵⁶

At times project management also involved informing and changing government opinion. Aeronautics programs within NASA, because of the low levels at which they were traditionally funded, had never required close oversight by the General Accounting Office (GAO). The large budget and greater visibility of the Aircraft Energy Efficiency Program (ACEE) suddenly brought it unwanted attention. The first draft of the General Accounting Office's 1979 review, though generally favorable toward the ACEE program, was highly critical of the advanced turboprop project. It concluded with the statement that the "GAO believes that much of the fuel savings under ACEE attributed to the turboprop will not be realized. "⁵⁷

The draft's "negative tone" and "misleading and distorted view of the program" deeply concerned NASA Lewis project managers who feared the repercussions it would have on funding decisions.⁵⁸ They quickly went on the attack. Center Director John Klineberg heatedly responded that the GAO had treated the turboprop project unfairly in comparison with the other aircraft efficiency projects, calling the GAO ignorant of the project's "inherent uncertainties."⁵⁹

NASA Lewis project managers prevailed in the battle against the negativity of the GAO draft report. The final publication specifically contained a retraction. The "GAO carefully reevaluated its presentation and made appropriate adjustments where it might be construed that the tone was unnecessarily negative or the data misleading." An example of these "appropriate adjustments" is apparent in a comparison of how one sentence changed from the draft to the final version. In the draft, the sentence appeared as: "The Task Force Report shows that in 1975 there was considerable disagreement on the ultimate likelihood of a turboprop engine being used on commercial airliners."⁶⁰ In the final publication, the GAO amended the same sentence to: "The possible use of turboprop

engines on 1995 commercial aircraft is still uncertain, but has gained support since 1975."⁶¹ These editorial changes giving the report a positive spin indicate the effectiveness of project managers in changing public opinion. Everyone, it seemed, had begun to associate the advanced turboprop technology with the possibility of bringing about an aeronautical "revolution," a paradigm shift, or as Forbes magazine headlined in 1984, "The Next Step." As surely as 'jets drove propellers from the skies," the new "radical designs" could bring a new propeller age to the world.⁶²

It is important to underscore how important the interpersonal skills of the project managers were to continuation of the program throughout this enabling technology phase. They were responsible not only for managing the project's technology, but also for enabling, proving, maintaining, and adjusting support for the turboprop. They continued to push this controversial technology against the conservative interests of the government, industry, and the public. Their consistent success paved the way for the third stage.

After two years of work, the advanced turboprop idea began to attract greater commercial interest. As a result of NASA's advocacy efforts, news articles began to predict the coming propeller "revolution." All indicators pointed to the introduction of the new turboprops on commercial aircraft by the 1990s. With the small-scale model testing complete, a data base, and an acceptable design methodology established, the project moved into its most labor and cost intensive phase —that of large-scale integration. The project still had serious uncertainties and problems associated with transferring the designs from a small-scale model to a large-scale prop-fan. Could engineers maintain propulsion efficiency, low noise levels, and structural integrity with an increase in size? The Large-Scale Advanced Prop-fan (LAP) project initiated in 1980 would answer these scalability questions and provide a database for the development and production of full-size turbofans.

As a first step, NASA had to establish the structural integrity of the advanced turboprop.⁶³ Project managers initially believed that in the development hierarchy performance came first, then noise, and finally structure. As the project advanced, it became clear that structural integrity was the key technical problem.⁶⁴ Without the correct blade structure, performance could never achieve predicted fuel savings. NASA awarded Hamilton Standard the contract for the structural blade studies that were so crucial to the success of the whole program. In 1981, they began to design a large-scale, single-rotating prop-fan made of composite material. Five years later they completed construction on a 9-foot-diameter design very close to the size of a commercial model. The model was so large that no wind tunnel in the United States could accommodate it. The turboprop managers decided to risk the possibility that the European aviation community might benefit from the technology that NASA had so arduously perfected. They shipped the large-scale propeller, called the SR-7L, to a wind tunnel in Modane, France, for testing. In early 1986, researchers subjected the model to speeds up to Mach 0.8 with simulated altitudes of 12,000 feet. The results confirmed the data obtained from the small model propeller designs. The large-scale model was a success.

Success spawns imitators. While NASA continued to work with Allison, Pratt & Whitney —and Hamilton Standard to develop its advanced turboprop, General Electric (GE)—Pratt & Whitney's main competitor— was quietly developing an alternative propeller system. A feature of radical inventions is that competitors often introduce alternative forms of a similar technology before one form can prevail over another. Historians of technology have shown many cases of "interpretative flexibility" when "two or even more social groups with clearly developed technological frames [artifacts] are striving for dominance in the field."⁶⁵ This happened when General Electric introduced its own radical alternative to NASA's advanced turboprop project-the Unducted Fan (UDF). GE sprang the unducted fan on NASA completely by surprise.

In NASA's design, the propeller rotated in one direction. This was called a single rotation tractor system and included a relatively complicated gearbox. Since one of the criticisms against the turboprop planes of the 1950s (the Electra, for example), was that their gearboxes required heavy maintenance, GE took a different approach to prop-fan design. Beginning in 1982, GE engineers spent five years developing a gearless, counter-rotating, pusher system. They mounted two propellers (or fans) on the rear of the plane that literally pushed it in flight, as opposed to the "pulling" of conventional propellers. In 1983, the aircraft engine division of General Electric released the unducted fan design to NASA shortly before flight tests of the NASA industry design were scheduled. Suddenly there were two turboprop projects competing for the same funds. Nored recalled: "They wanted us to

drop everything and give them all our money and we couldn't do that."⁶⁶ NASA Headquarters endorsed the "novel" unducted fan proposal and told NASA Lewis to cooperate with General Electric on the unducted fan development and testing.

Despite NASA's initial reluctance to support two projects, the unducted fan proved highly successful. In 1985, ground tests demonstrated a fuel conservation rate of twenty percent.⁶⁷ Development of the unducted fan leapt ahead of NASA's original geared design. One year later, on August 20, 1986, GE installed its unducted fan on the right wing of a Boeing 727. Thus, to many NASA engineers' dismay, the first flight of an advanced turboprop system demonstrated the technical feasibility of the unducted fan system —a proprietary engine belonging entirely to General Electric, rather than the product of the joint NASA/industry team. Nevertheless, the competition between the two systems, and the willingness of private industry to invest its own development funds, helped build even greater momentum for acceptance of the turboprop concept.

NASA engineers continued to perfect their single-rotating turboprop system through preliminary stationary flight testing.⁶⁸ The first step was to take the Hamilton Standard SR-7A propfan and combine it with the Allison turboshaft engine and gearbox housed within a special tilt nacelle. NASA engineers conducted a static or stationary test at Rohr's Brown Field at Chula Vista, California, where they mounted the nacelle, gearbox, engine, and propeller on a small tower. The stationary test met all performance objectives after fifty hours of testing in May and June 1986. This success cleared the way for an actual flight test of the turboprop system. In July 1986 engineers dismantled the static assembly and shipped the parts to Savannah, Georgia, for reassembly on a modified Gulfstream II with an eight-blade, single-rotation, turboprop on its left wing.⁶⁹ The radical dreams of the NASA engineers for fuel efficient propellers were finally close to becoming reality. The plane contained over 600 sensors to monitor everything from acoustics to vibration. Flight testing-the final stage of advanced turboprop development-took place in 1987 when a modified Gulfstream II took flight in the Georgia skies. These flight tests proved the predictions of a twenty to thirty percent fuel savings (made by NASA in the early 1970s) were indeed correct.

On the heels of the successful tests, of both the GE and the NASA-industry team designs, came not only increasing support for propeller systems themselves, but also high visibility from media reports forecasting the next propulsion revolution. The New York Times predicted the "Return of the propellers" while a Washington Times headline read, "Turboprops are back!"⁷⁰ Further testing indicated that this propulsion technology was ready for commercial development. As late as 1989, the U.S. aviation industry was "considering the development of several new engines and aircraft that may incorporate advanced turboprop propulsion systems."⁷¹ But the economic realities of 1987 were far different from those predicted in the early 1970s. Though all the technology and social problems standing in the way of commercialization were resolved, the advanced turboprop never reached production, a casualty of the one contingency that NASA engineers never anticipated —that fuel prices would go down. (See figure 5) Once the energy crisis passed, the need for the advanced turboprop vanished.

One of the main difficulties in the development of a radical new technology is the potential project threatening problems that arise. If they are left unsolved they can destroy an entire project. Historian of technology Thomas Hughes called these problems "reverse salients." Hughes argues that all large technological systems (of which the turboprop is an example) include political, economic, social, and technological components.⁷² These system components are interrelated so that if one of the components is changed or altered in any way, the rest of the system will also be affected. The systems themselves grow and gain momentum by the process of removing "reverse salients," which arise and could potentially cause the system to fail. An example will help clarify the importance of solving these critical problems. In 1878, Thomas Edison encountered a technological reverse salient in his attempt to develop his electric-lighting system. This problem was the short-lived filament of the incandescent bulb. Edison realized that even if he solved this problem, a further economic reverse salient remained. The expense of the copper wire needed to link the entire system together was cost prohibitive for potential wide-scale acceptance. If Edison could not reduce the amount of copper needed for his electric system, then gas-lighting systems would become the more attractive alternative to the problem of street lighting. What is important to understand is that either the technological or the economic reverse salient could have caused the Edison system of electric-lighting to fail.⁷³

Like Edison, the managers of the turboprop project also confronted a variety of critical problems. These problems included economic (the necessity of maintaining a favorable ratio of cost to implement turboprop technology versus savings in fuel efficiency), political (how to receive funding for a long-term project), social (how to implement a technology which the public could perceive as a "step backward"), institutional (how to successfully manage the government, industry, and academic relations), and technical (how to actually build a turboprop that improved fuel efficiency by twenty to thirty percent). Each of these problems had the potential to sabotage the entire system. NASA engineers had their own, more practical and direct term for "reverse salient" —a "showstopper." In 1984, engineers listed a number of technical show-stoppers that threatened to derail the project if left unsolved—for example, unacceptable levels of cabin noise.⁷⁴

As system-builders solve critical problems, the system itself generates momentum. This momentum continues to increase and build until, according to Hughes, either a conversion, a catastrophe, or a contingency occurs. Conversions and catastrophes break momentum through either a change in societal belief, like a religious conversion, or a massive technological failure, like a nuclear-reactor catastrophe. But, it is the role of contingency which interests us here as the key factor in the current neglect of the advanced turboprop technology. Hughes identified one particular "contingent environmental change" that altered the course of the entire automobile industry —the energy crisis. He argues, "The oil embargo of 1973 and the subsequent rise in gasoline prices ultimately compelled U.S. automobile manufacturers to change substantially an automobile design that had been singularly appropriate to a low-cost-energy environment."⁷⁵

The development and subsequent neglect of advanced turboprop technology is the result of this same environmental contingency. In the early 1970s, the energy crisis created a situation which made it a national necessity for the government to explore new ways to conserve fuel. What the managers of the Advanced Turboprop Project (ATP) did not anticipate and could not control was a decrease in the cost of fuel. As the energy crisis subsided in the 1980s and the fuel prices decreased, there was no longer a favorable ratio of cost to implement turboprop technology versus savings in fuel efficiency. As John R. Facey, advanced turboprop program manager at NASA Headquarters, wrote, "An all new aircraft with advanced avionics, structures, and aerodynamics along with high-speed turboprops would be much more expensive than current turbofan-powered aircraft, and fuel savings would not be enough to offset the higher initial cost."⁷⁶ In the case of the ATP, its managers overcame all of their critical problems. However, when contingent economic conditions changed so that fuel cost was no longer a critical problem, regardless of the technical success of the project, the advanced turboprop lost its potential market in the industrial world.

Yet Keith Sievers, at that time the manager of the ATP, along with a handful of project staff, was convinced that the NASA industry team had made a significant contribution to aviation that ought to receive recognition. To win the Collier Trophy, he again summoned up the advocacy skills that had proved so valuable in bringing the controversial advanced turboprop to the point of technical feasibility. He used them to lobby for the prestigious Collier Trophy among the wide aeronautical constituency that had participated in advanced turboprop development. NASA Headquarters initially expressed some reluctance to lobby for awarding a prize for technology that was unlikely to be used —at least in the near future. But the timing was perfect. There was little competition from NASA's space endeavors since staff in the space directorate were still in the midst of recovering from the tragic Challenger explosion. As a result, the National Aeronautic Association awarded NASA Lewis and the NASA Industry Advanced Turboprop Team the Collier Trophy at ceremonies in Washington, DC. Today, the technology remains "on the shelf," or "archived," awaiting the time when fuel conservation again becomes a necessity.⁷⁷

Despite the current neglect of the advanced turboprop, this case study demonstrates how radical innovation can emerge from within a conservative, bureaucratic government agency. The government—not industry—assumed the risk for developing the new technology. It used taxpayers' money to advance a radical idea to the point of technical feasibility. Engineers involved in the project used advocacy to build a consensus among the members of the aeronautical community that the advanced turboprop would prove a viable alternative to the far less energy efficient turbofan technology. Indeed, the technical and social achievements of the project were convincing enough to drive General Electric to invest its own funds to develop a competing design. This competition was evidence of wide acceptance for the turboprop concept.

The Collier Trophy in 1987 was presented to the "Lewis and the NASA Industry Advanced Turboprop Team.'' The team, defined in its widest possible context, included General Electric's independent contribution of the UDF and its subsequent flight testing by NASA. In contrast to previous Collier trophies in aeronautics won by the NACA, no individual received special mention. Certainly, throughout the eleven years of its existence the project had encouraged inventiveness of individuals in a variety of disciplines, from highly theoretical contributions in blade design and acoustics to more routine testing.

Participants in the project ran the gamut from government, university, and industry researchers. But what the prize recognized above all was the project's management genius. NASA Lewis managers did not simply manage contracts. They kept the project alive. They used advocacy to win industry participation and cooperation, as well as stimulate competition. They pushed both the technical and the social aspects of the project to create the system's momentum. Yet once the energy crisis passed, this momentum was insufficient to dislodge the massive technological momentum of the existing turbofan system.

NASA engineers involved in the ATP project still remain confident that the future economic conditions will make the turboprop attractive again. When fuel becomes scarce and fuel prices begin to rise, the turboprop's designs will be "on the shelf' ready to respond with tremendous fuel-efficient savings. But, technological neglect is not the enthusiastic success on which NASA engineers built their careers. Donald Nored wistfully reflected on the project and said, "We almost made it. Almost made it."⁷⁸

78. Noted interview.