advanced high-speed aircraft: the next 30 years

Chapter II

ADVANCED HIGH-SPEED AIRCRAFT:THE NEXT 30 YEARS

Air transport technology is entering a newevolutionary phase. Both American and Euro-pean manufacturers are midway in the develop-

;

ment of the next generation of subsonic jet-liners, a first step along a path to create more <v

energy-efficient equipment for the air carriers.

The pattern is being established by the BoeingCompany’s 757 short-range transport and medi-um-range 767 and in Europe by the Airbus In-dustrie's A-310, another new medium-range air-craft , al l scheduled for introduction into service , -~ ‘,,:,J-:,.,/,during 1981 to 1983. New long-range aircraft, “ , ‘” ‘“*% “-”including derivatives of present models, are ex-pected to be introduced later in the decade by a Photo credlf. A/rbus Industne

number of manufacturers.Airbus Industrie's A-310

These new models are incorporating what theindustry calls “phased improvements” in tech- provement in fuel efficiency over the decade tonology covering materials, manufacturing tech- offset rising energy costs. Further substantialniques, aerodynamics, cockpit automation, and technological advances are expected in thepropulsion. The goal is a 15- to 20-percent im- 1990’s and beyond the year 2000.

Boeing’s 767 medium-range transport

Photo credit: Boeing A/rcraft Co

21

22 ● Advanced High-Speed Aircraft

OUTLOOK FOR NEW AIRCRAFT TYPES

Intercontinental versions of these aircraft,designated as advanced subsonic transports(ASUBTs), probably will carry between 200 and400 passengers, being sized to replace 707s andDC-85, which will be 30 years old by 1990, andto fill market gaps between these early jets andthe present generation of widebody aircraft. Therange of the ASUBTs will be about the same asthe present long-range jets or slightly greater—up to 6,500 nautical miles at cruising speeds ofup to 600 mph (Mach 0.85).1

IJ. M. Swihart, The Boeitlg New Airplane Family, paper pre-sented to the American Institute of Aeronautics and Astronautics,15th annual meeting, Washington, D. C., Feb. 6, 1979.

,

-.

Under the evolutionary approach, there willbe no quantum jump in size or performance,such as occurred with the widebody jets intro-duced in the early 1970’s, to greatly increaseproductivity (the number of seat-miles gener-ated by an aircraft per unit of time). Instead, theASUBTs will contain improvements leadingtoward reduced operating costs. The industryconsiders it possible over the long run to obtainfuel consumption rates in the ASUBTs that are20 to 30 percent better per seat-mile than the2,450 Btu per seat-mile typical of today’s wide-body jets.

Total operating costs (in constant dollars)could be perhaps 10 to 20 percent below those of

Photo credit: American A/r//nes

Boeing 707 transport

the most efficient aircraft now in service, evenwith increased fuel prices. High-bypass-ratioengines and noise suppression materials used ininlets and ducts will allow quieter operationover a wide range of power settings to increaseenvironmental acceptance.23

Beyond 1990, further development of subson-ic aircraft is possible and, therefore, so is thecontinuation of the trend toward more fuel-effi-cient, economic, and environmentally accept-able aircraft. These aircraft might be derivationsof the ASUBTs introduced in the 1980’s or mightbe of an entirely new design. There is also apossibility that very large advanced aircraft(400 to 800 passengers) will be developed to pro-vide service on high-density transcontinentaland transoceanic routes.

The demand for very large aircraft, however,is likely to be restricted because they could be

‘Ibid., pp. 1, 4-5.‘OTA Working Paper, Lockheed-California Co., Feb. 5, 1979.

productive only on routes with extremely highpassenger travel densities. At present, no esti-mates are available as to when there will be asufficient number of high-density routes to war-rant undertaking the development of such anaircraft.

A further option would be the development ofan advanced supersonic transport (AST), a sec-ond-generation aircraft with performance capa-bilities substantially better than those of theBritish-French Concorde and the Soviet TU-144.An AST operating at more than twice the speedof sound (Mach 2 + ) offers the only remainingpath to significantly greater aircraft productivi-ty. It could haul twice the number of passengersas a subsonic airliner of equivalent size in thesame time period. There are major questions,however, whether it is possible to create an ASTthat is both economically viable and environ-mentally acceptable. These questions are ana-lyzed at length later in this study.

60-285 0 - 8J - 3


Looking beyond an AST to the prospects ofhypersonic cruise aircraft coming into commer-cial service, the consensus of those involved inthis study was that it will not happen before2010. This judgment is based on the presentstatus of knowledge of the hypersonic regime,the time it would take to obtain a state of tech-nology readiness to design such a craft, plus thetime needed to go through a development cycleto produce one. Although research has beenconducted on problems associated with hyper-

sonic aircraft, the knowledge base is small com-pared to the status of knowledge in the super-sonic area. The technical problems and require-ments of a hypersonic transport, although moreextensive and severe, do contain all the require-ments of a supersonic aircraft. Therefore, itseems reasonable to assume that supersonictechnology readiness must be achieved beforehypersonic technology readiness and that anydecision to leapfrog the supersonic system for ahypersonic aircraft should come after super-sonic technology readiness is achieved.

A similar situation exists for suborbital flight.Although technology advances appropriate tothis type of flight could come from the NationalAeronautics and Space Administration (NASA)space shuttle program, it is doubtful that thistechnical base could be translated into a sub-orbital commercial passenger airplane withinthe 1980-2010 time frame for this study.

As indicated, the consensus decision to deletethe hypersonic and suborbital commercialtransports from the current study was made onpractical considerations. This decision by nomeans implies that research should not continuein these areas in order to determine the potentialof such aircraft.

Illustration’ Courtesy of Lockheed Aircraft Corp.

Artist’s concept of Lockheed’s hypersonic cruise aircraft

Ch. II—Advanced High-Speed Aircraft The Next 30 Years ● 25

WORLD REQUIREMENTS FOR NEW AIRCRAFT

Perhaps one of the more surprising develop-ments during 1979, in view of economic uncer-tainties, continuing inflation, and an energysupply picture clouded by unrest in Iran and ris-ing oil prices, was the placement of multibilliondollar orders for the 757, 767, and A-310 by theair carriers. Boeing’s sales for the year increasedto an unprecedented $12 billion, according tocompany estimates. Moreover, these orderswere booked in the face of an expected U.S. eco-nomic recession in 1980 and at a time when thelong-range effects of passenger fare deregulationon airline revenues are far from clear.

Underlying the airlines’ decision to order hun-dreds of new planes are projections for con-tinued strong growth in air travel demand. An-nual traffic growth has averaged 11 percentsince 1977 and hit 15.6 percent in the first half of1979. While industry analysts expect a recessionto hold growth to only 2 percent in 1980, theyare forecasting an average annual traffic expan-sion of 7 percent through 1990.

If air traffic increases by only 6 percent annu-ally on average, passenger-miles over the next30 years would quadruple. A potential also ex-ists for a doubling of present airline route-milesin this period as more areas of the world, suchas the Orient, are opened to commercial traffic.

These projections assume that there will be nomajor disruptions in the growth of the worldeconomy and that the airlines, along with othertransportation sectors, will be able to meet their

needs for fuel that is becoming increasinglymore expensive. If traffic growth holds up, sowiIl the market for new aircraft. Both the air-craft manufacturers and the airlines agree an in-crease in passenger-carrying capacity already isindicated for mature travel markets over thenext decade, particularly for short- to medium-range routes.

Thus, based on current trends and projec-tions, there is a potential market over the1980-2010 period for 6,500 to 8,500 short- andmedium-range aircraft, both additional and re-placement. This part of the market could meansales totaling $235 billion in 1979 dollars. Overthe same 30-year period, the potential marketfor long-range aircraft (more than 2,700 nauti-cal miles) is estimated at 2,200 to 3,300 unitswith a sales volume of $150 billion. Should asuccessful AST be developed, it is believed itcould capture about one-third of the dollar vol-ume of this market with sales of about 400 air-craft between 1990 and 2010. But many techni-cal problems and other uncertainties need to beovercome in the near term before it is possible tocontemplate whether an AST is indeed feasiblein all respects.

To gain an appreciation of the magnitude ofthe difficulties—and the scope of the issues—itis instructive to review briefly the short historyof supersonic flight programs in the UnitedStates and abroad and to look at where super-sonic technology stands today.

BEGINNINGS OF SUPERSONIC TRANSPORT–THE CONCORDE

In the late 1950’s, commercial aircraft design-ers began turning their attention to passengertransports that could add the element of speedto aircraft productivity. In Great Britain andFrance, studies were initiated independentlyabout 1956 into the feasibility of supersonicpassenger aircraft. In the United States, techni-cal feasibility studies were begun slightly later.However, by 1959, NASA was giving seriousconsideration to a supersonic transport that

would be a civilian derivative of the XB-70bomber which was later canceled.

For the Europeans, the impetus to develop asupersonic transport came from several sources.In Great Britain, it was seen as a way of recoup-ing the loss in prestige and market advantagesuffered by the failure of the Comet jet trans-port. By the time the Comet’s problems hadbeen corrected and the aircraft was ready to re-

enter service, the U.S. Boeing 707 and DC-8 hadbuilt up an unassailable lead. In the words of SirCyril Musgrave, permanent secretary of theUnited Kingdom Aviation Ministry in 1956,“All the major airlines were buying the 707 orthe DC-8 and there was no point in developinganother subsonic plane. We felt we had to goabove the speed of sound, or leave [the mar-ket].” 4

The British aircraft industry had seriousdoubts about the economic soundness of the su-personic transport proposed at that time. Thedevelopment costs were estimated to be high, *the market for such an aircraft was uncertain,and the operating cost for a New York-Londonnonstop flight at Mach 1.2 to 1.8 was projectedto be five times greater than the cost of subsonicjets then in service. Designers later increased thespeed and capacity of the proposed aircraft, but

4P. Gillman, “Supersonic Bust: The Story of the Concorde, ”Atlantic, vol. 239, January 1977, p. 73.

● Depending on range, speed, and payload, the estimates at thattime varied from $165 million to $265 million. These estimatesproved to be wildly optimistic—the British Government’s finalfigures on Concorde development costs were $3.25 billion, sharedby Britain and France.

the industry members of the British SupersonicTransport Aircraft Committee remained skepti-cal.

While study and debate were going on in Bri-tain, the French Government and aircraft indus-try were also conducting preliminary studies ofa supersonic transport. The French design con-cept, like the British, was a Mach 2.0, all-alumi-num aircraft, but it had a shorter range and ahigher payload intended to serve a European,near Eastern, and African travel market, InFrance, the impetus for developing such an air-craft came largely from outside the sphere oftechnology and economics. The French Govern-ment was determined to enhance the role ofhigh-technology industries in both the nationaland the European economy. A supersonic trans-port was perceived both as a response to “theAmerican Challenge” and as a means to gener-ate the expertise and skills needed to build andsustain a European industry that could competein high-technology aerospace engineering.

Doubts about development and productioncosts and about the eventual world market forthe aircraft continued to nag the British and the

Ch. II—Advanced High-Speed Aircraft: The Next 30 Years ● 27

French. In 1960, both began to cast about forways to lessen cost and to reduce the techno-logical and capital risks. Negotiations betweenthe two governments began in the summer of1960 and culminated 2 years later in November1962 with an agreement for a joint effort tobuild an aircraft appropriately called Concorde.The design team consisted of the British AircraftCorp. and Sud-Aviation (later reorganized asAerospatiale) , with Bristol-Siddeley andSNECMA providing the engine.

The aircraft that emerged from the jointdesign effort had a thin, fixed ogee wing andwas powered by a “civilianized” version of theOlympus 22R—a then lo-year-old military en-gine that had been developed by Bristol-Sid-deley for the TSR-2 multimission combat plane(which was canceled in 1965 after $532 millionhad been spent). The Concorde originally wasintended to have a payload of 112 to 126 passen-gers (later reduced to 90 to 100) and a range of3,500 to 4,000 nautical miles. The speed of theConcorde was limited to Mach 2.2 because of adecision to employ aluminum instead of titani-um, which was more difficult and risky to usebut would have allowed speeds up to Mach 3.

The cost of the Concorde development pro-gram was estimated in 1965 at $400 million andlater revised to $770 million, then to $1.26 bil-

lion, $1.75 billion, and ultimately $2.63 billionby 1975. The final cost figures quoted by theBritish Government in 1977 were $3.25 billionfor development and $0.85 billion more for pro-duction costs and losses sustained in operatingthe Concorde, making a total program cost ofover $4 billion. Sales estimates made at varioustimes during the course of the program variedwidely—from 100 to 500—and the projectedpurchase price fluctuated accordingly, from $30million to $56 million.5 6 But only 16 Concordeswere built, 2 for testing and 14 for sale; 9 havebeen sold at a price of $80 million each to theState-owned airlines of the two countries,British Airways and Air France. The Concordeproduction line was closed in September 1979and the remaining seven planes were given tothe two airlines.

Construction of the first prototype Concordebegan in 1965. The first test flight was in March1969, and the first supersonic flight took place 7months later in October 1969. Commercial pas-senger service began in January 1976 with flightsfrom Paris to Rio de Janeiro (via Dakar) by AirFrance and from London to Bahrain by BritishAirways. Service from Paris and London to

‘D. Rodd, “The Concorde Compromise: The Politics of Deci-sion-Making, ” Bulletin of the Atomic Scientists, vol. 34, No. 3,March 1978, p. 47.

‘Gillman, op. cit., p. 78.

Photo credit: British Aircraft Corp

The Concorde

28 Ž Advanced High-Speed Aircraft

Washington started on May 24, 1977. 7 T h eConcorde now operates on routes from Parisand London to New York, Washington, Caracas(via the Azores), Rio (via Dakar), and Bahrain.The level of service for the two airlines com-bined was about 110 flights per month for thefirst year of operation and has risen to about140 per month since inauguration of flights toNew York in December 1977. Load factors forall routes have averaged slightly under 50 per-cent, but have reached as high as 85 to 90 per-cent for the North Atlantic routes. g The aircraftpresently operates at an average of 70-percentcapacity on these routes.

While many feel that the Concorde programproved economically disastrous, several bene-

7F. Melville, “The Concorde’s Disastrous Economics, ” Fortune,Jan. 30, 1978, p. 67.

‘P. Sweetman, “Concorde First Passenger Year, ” Flight Interna-tional, Feb. 12, 1977, p. 358.

fits were obtained from it. First, the Concordeshowed that an aircraft could be developed andproduced which is capable of safe, sustainedrevenue operations at supersonic speeds. Muchhas been learned about commercial supersonicaircraft operations which would be extremely

beneficial to any future generation of supersonictransports. Secondly, the British and Frenchgained much experience in working together,especially in learning how to manage an ad-vanced technology program with many coordi-nation problems. The Concorde has aided theFrench in a military regard, specifically in thetechnology applied to the Mirage series offighters (Mirage 2000) which is capable ofspeeds of Mach 2.5. Last, the project helpedpreserve and focus the French and British com-mercial aerospace industry, which has gone onto become a major contender in the world com-mercial air transport market.

THE AMERICAN SUPERSONIC TRANSPORT (SST) PROGRAM

The official entry of the United States in thesupersonic transport competition dates fromJune 1963 when President John F. Kennedy an-nounced at the commencement exercises of theU.S. Air Force Academy:

It is my judgment that this Governmentshould immediately commence a new programin partnership with private industry to developat the earliest practical date the prototype of acommercially successful supersonic transport su-perior to that being built in any other country inthe world . . .9

Actually, the U.S. interest in an SST beganmuch earlier. The Director of the NASA Officeof Advanced Research Programs had testifiedbefore the House Committee on Science and As-tronautics about the prospects of an SST asearly as 1960. 10

‘John F. Kennedy, commencement address, U.S. Air ForceAcademy, June 5, 1963, in Public Papers of the President, speechNo. 22., cited in M. E. Ames, Outcome Uncertain: Science and thePolitical Process (Washington, D. C.: Communications Press,1978), p. 50.

IOU*S. congress, committee on Science and Astronautics, %e-cial Investigating Subcommittee, Supersonic Air Transport, Hear-ings, May 17, 18, 19, 20, and 24, 1960, 86th Cong., 2d sess.(Washington, D. C.: Government Printing Office, 1960), p. 9.

From the outset, the U.S. concept of an SSTwas shaped by two primary considerations—technological preeminence and economic viabil-ity. It was recognized in President Kennedy’sspeech and specifically stated by NASA and theFederal Aviation Administration (FAA) laterthat the SST had to be a “better airplane” thanthe Concorde or the Soviet TU-144 and that“better” meant more advanced technologically

and more productive economically. Thus, theinitial design concept of the SST called for a400,0()()-lb titanium airplane capable of flying atMach 2.7 or faster with a range of at least 4,000nautical miles and a payload of 125 to 160 pas-sengers. The importance of sonic boom was alsorecognized, and the FAA request for proposalsin August 1963 specified that overpressure couldnot exceed 2 lb/ft2 during acceleration and 1.5lb/ft 2 during supersonic cruise. Further, the SSThad to be at least as quiet during approach andtakeoff as subsonic jets. 1

1

In January 1964, three U.S. aircraft manufac-turers submitted design proposals to FAA. The

I IM E, Ames, Outcome uncertain: Science and the pO/itJca/Proce;s (Washington, D. C.: Communications Press, 1978).

Ch. II—Advanced High-Speed Aircraft: The Next 30 Years . 29

Lockheed design theoretically was the fastest,flying at Mach 3.0 with 218 passengers. How-ever, the range of the aircraft was limited. TheLockheed “double delta” wing was designed toprovide safe and efficient operation at lowspeeds while offering good aerodynamic charac-teristics in the supersonic cruise regime. Boeingproposed a Mach 2.7 aircraft with a small pay-load of 150 passengers. The unique feature ofthe aircraft was a variable-sweep wing—devel-oped by Boeing in its unsuccessful bid for theTFX military fighter-bomber—which added me-chanical complexity to the design and was per-ceived as a serious technological risk. NorthAmerican Aviation, Inc., (now Rockwell Inter-national) proposed a commercialized version ofthe B-70 bomber design, which had a fixed deltawing and a forward stabilizing wing called acanard. The design speed was Mach 2.65 and itcarried 187 passengers. Three engine manufac-turers—Pratt & Whitney, Curtiss-Wright, andGeneral Electric—proposed various turbojetand turbofan designs, none of which were clear-ly superior to the others in noise characteristicsor efficiency. 12

The competing aircraft designs were eval-uated by the Government and a panel of 10 air-lines. None met both the range and payload re-quirements specified by FAA and none prom-ised to fulfill the general objective that the air-craft be profitable in commercial operation. InMay 1964, FAA awarded contracts to Boeingand Lockheed for further airframe designstudies and to General Electric and Pratt &Whitney for additional work on the engine. Im-provements in three fundamental areas weredesired: aerodynamic design (a fixed wing or avariable-sweep wing), engine performance(thrust, fuel efficiency, and noise), and operat-ing economics (payload, range, and commercialprofitability). Of these, the economic problemwas the most intractable.

In December 1966, after 2½ years of addi-tional design studies and reviews by 3 presiden-tial committees, the National Academy of Sci-ences, 7 congressional committees, 13 FederalGovernment agencies and departments, and un-

121 bid., p. 59-60.

told analyses by profit and nonprofit consultingorganizations, FAA announced that it wasawarding contracts to Boeing to build the air-frame and to General Electric to produce theengine. This decision was taken despite the find-ings of two FAA-sponsored studies—one by theRAND Corp. in 1962 and the other by the Stan-ford Research Institute—which concluded thatthere was “no direct economic justification foran SST program.”13 The cost of the program bythen had reached $311 million, PIUS another$200 million soon to be requested to help fi-nance the construction of two preproductionaircraft. Furthermore, there were major techno-logical problems of range, payload, weight, andengine noise still to be solved.

Why then did the Government (specificallyFAA) proceed with the SST program? In part, itwas because aircraft designers and Governmenttechnical experts presented strong argumentsthat, given enough money, time, and hardwork, the technological problems could besolved. There was some wishful economicthinking, supported by a series of studies com-missioned by FAA which raised the market fore-cast from the original estimates of 25 to 125 air-craft to 500 and eventually to over 800.14 Not tobe overlooked was the personal commitment ofthose in key positions at FAA from 1960 to 1970—Lt. Gen. Elwood L. Quesada, Najeeb Halaby,Maj. Gen. William F. McKee, Gen. Jewell C.Maxwell, and William M. Magruder. All werepublicly avowed proponents of an AmericanSST, and all had had previous involvement withhigh-technology aerospace programs in militaryor industrial settings. They never voiced anydoubt that the SST could, and should, be builtor that it would be technologically and commer-cially superior to the Concorde and the TU-144.

However, these factors may not have sus-tained the SST program, if it had not been thatthe SST had also become a political symbol ofthe preeminence of U.S. technology. The SSTwas seen, at that time, as a counterpart to the

13Fi~al Report: A n ECOnOrnir Analysis of the Supersonic Trans-port (Stanford Research Institute, SRI project No. ]SU-4266,August 1963), p. 1.

14L. D. C]ark, “controversy About Supersonic Transport in theUnited States, ” Miner-m, vol. 12, No. 4, 1974, p. 427.

.

30 . Advanced High-Speed Aircraft

Apollo man-on-the-moon program. By failingto keep up with foreign competition the U.S.aircraft industry might lose its leadership in theworld market. This argument was advanced in1962 by FAA Administrator Halaby who listedthe consequences of failure to develop an SST asloss of world civil transport leadership, an un-favorable balance-of-payments situation, loss ofexports, declining employment in the U.S. air-craft industry, and dependence on foreignsources.15 Halaby warned that a successful Con-corde, with no U.S. equivalent, could “conceiv-ably persuade the President of the United Statesto fly in a foreign aircraft.”16

By 1968, after a total of $650 million had beenappropriated for the program, the SST was stillbeset with technological difficulties and politicalcontroversy. Boeing announced that the swing-wing design would have to be scrapped on ac-count of its mechanical complexity and the 2 5tons it. added to the aircraft weight which af-fected the range requirements. The redesign tofixed-wing configuration would set back theschedule and raise the development costs of theaircraft. The estimated cost of the overall pro-gram, through testing and two preproductionaircraft, had grown to approximately $4.5 bil-lion of which the Government share was about$1.7 billion. The $4.5 billion broke down into:total costs through the prototype of $1.6 billion(of which the Government would supply $1.3billion); certification cost of $0.8 billion (ofwhich the Government would supply $0.4 bil-lion); and production startup cost of $2.0 billionto $2.5 billion (which the industries would un-dertake without Government support). Theforecasts of sales, return on investment, - a n doperating costs were still not very encouraging.

At about the same time, two new issuesemerged that were to prove decisive for the SSTprogram. The first of these was mounting con-cern about potential environmental and healthconsequences of a fleet of SSTs. Public reactionto sonic boom tests conducted by FAA con-

ISM. Horwitch, “The American SST Experience—The Trans-formation of Multifaceted Technological Enterprises, ” workingpapers for AAAS Symposium, February 1972, p. 5.

“N. Halaby, memorandum to President John F. Kennedy,11/15/62 (JFK Library, President’s Office Files), cited in M. Hor-witch, loc. cit.

vinced Boeing that it would be necessary torestrict supersonic flights by the future SST toover water routes, thus eliminating about one-third of the trips on which the original SST mar-ket estimates had been based.

The anticipated noise that the SST wouldgenerate over populated areas during takeoffand landing touched off intense public protest.The most heated controversy about environ-mental impacts, however, centered around thepossible changes in the upper atmosphere thatmight be caused by hundreds of SSTs operatingworldwide. Evidence was adduced to show thatthe water vapor and gaseous emissions releasedby the SST in the stratosphere could deplete theozone layer and might lead to irreversibleclimatic change or an increase in the incidenceof skin cancer. There was also concern aboutpossible health hazards to passengers and crewfrom exposure to cosmic radiation in prolongedand repeated high-altitude flights. These con-cerns, however, were based on preliminaryscientific evidence. They have since been shownto be overblown, but at the time they generatedwidespread fear of potentially catastrophicenvironmental damage from the SST.

A second issue which became the subject ofpublic debate centered on the social implicationsof high technology as represented by the SST.The SST was portrayed by some as an elitist air-craft, financed by taxpayer money for the bene-fit of a privileged few. It became another objectof a growing resistance to technology for itsown sake, especially when the costs of that tech-nology were high and its potential consequencesfor the health and well-being of present andfuture generations might be harmful. This viewwas summarized in a New York Times editorial:

The attitude . . . was that technology existsto serve mankind and that proposals to move itahead at great expense must be judged on thebasis of cost-benefit analysis of the widest andmost comprehensive sort .. .17

The widening of the debate over the SST toinclude issues of social goals and priorities wasto spell the cancellation of the program. Publicdiscussion about the appropriateness of the SST

17 Ames, op. Cit. P. 73.


as a technological undertaking for the Nation,coupled with the growing societal concerns andcost, brought the matter to a head in House andSenate votes on fiscal year 1972 appropriations.The cost of the program including preproduc-tion development was $1.6 billion. Design prob-lems for the airframe and engine were still to besolved. The commercial success of the airplanewas severely questioned. Fears about environ-mental effects added fuel to the debate. InMarch 1971, the House, by a vote of 217 to 203,deleted all SST funds from the Department ofTransportation appropriation for fiscal year1972. An amendment to restore SST funds wasdefeated in the Senate, 51 to 46. On May 1,1971, the Senate approved $156 million in ter-mination costs. Thus, after 8 years of R&D andan expenditure of approximately $1 billion, theUnited States withdrew from the supersonictransport competition.

The total cost of the original SST programthrough prototype and certification would havebeen shared by the Government and industry ona 73- and 27-percent basis, respectively. As in-dicated previously, the production startup costwould have been totally supported by industry.At the same time the program was canceled, 9U.S. trunk carriers, 2 supplemental, 1 leasingcompany, and 14 non-U. S. flag carriers had in-vested $59 million of risk money and $22million for delivery reservations for 122 U.S.SSTs. The manufacturers had invested approx-imately $322 million. The program was con-structed so that the U.S. Government invest-ment would have been returned on delivery ofthe 300th production aircraft.

The U.S. SST program did generate a numberof technical developments that have contributedto advancing aircraft technology. For example,in the area of aerodynamics, relaxed static sta-bility and variable camber flaps on the wingleading edge were developed and evaluated inthe U.S. SST program and have since been ap-plied to the F-16/fighter plane. With regard tohuman factors technology, various elements inthe 747 cockpit are direct descendants of devel-

opment work on the SST. Other examples in-clude digital displays and advanced navigationsystems developed for the SST that are nowbeing incorporated in the 767 aircraft design.

In the structures and materials area, the air-frame design problems associated with the SST—more complex than those associated with con-ventional subsonic designs—prompted the de-velopment of more sophisticated and accuratecomputerized structural design and analysismethods. Methods based on these SST develop-ments are currently employed in the design ofadvanced subsonic aircraft and are being ap-plied to automotive and other vehicle designs.Also, the work on titanium sandwich struc-tures, formerly conducted concurrently in theSST and 747 programs, contributed to the 747aircraft and is being applied to military aircraftand missiles. In the propulsion area, the originalSST program added substantially to the tech-nology of high-temperature turbines and ad-vanced materials which in turn led directly toimprovements in the high-bypass-ratio enginesused on most current subsonic transports.

In retrospect, the SST program was probablyneither as well-founded an undertaking as itssupporters claimed nor as ill-considered as itsopponents argued. The goal of the program, inbuilding two preproduction aircraft, was todetermine whether a technologically advancedand commercially viable supersonic passengeraircraft could be achieved. The program dem-onstrated that the technology available at thattime would have resulted at best in an economi-cally and environmentally marginal airplane.But it is also true that the technology base wasgreatly enhanced by the effort and that valuablelessons were learned. However, whatever wasachieved was lost from sight in the conflict thatled up to cancellation. One of the most impor-tant lessons learned is that a genuine and impor-tant national interest will have to be clearlyidentified before any future high-technologylarge-scale commercial undertaking can expectto receive significant Government support in thefuture.

32 . Advanced High-Speed Aircraft

Photo credit Nat/ona/ Aeronaut/es and Space Adm/n/straf/on

Cockpit of Boeing’s 747 aircraft

Photo credit Boeing Aircraft Corp.

Cockpit of Boeing’s 767 aircraft now under development

Ch. II--Advanced High-Speed Aircraft: The Next 30 Years “ 33

CURRENT STATUS OF SUPERSONIC TECHNOLOGY

Generic research on supersonic cruise aircrafthas been continuing at a low funding level sincecancellation of the SST program in 1971. Initial-ly, between 1971 and 1973, FAA had responsi-bility for this research and allotted it a totalbudget of $15 million, The program was trans-ferred to NASA in 1972 and named the super-sonic cruise aircraft research program. In 1979,the name was shortened to the SupersonicCruise Research (SCR) program. The total ap-propriation for the NASA program in the fiscalyears 1973 through 1979 was $72.9 million, oran average of about $10 million a year (table 2).

Table 2.—NASA Supersonic Cruise ResearchProgram R&D Expenditures

(in millions of dollars; FY 1973.79)

Propulsion . . . . . . . . . . . . . . . . . . . . . . . . . $29.5Structures and materials . . . . . . . . . . . . . 16.7System integration studies . . . . . . . . . . . 15.8Aerodynamics . . . . . . . . . . . . . . . . . . . . . . 5.1Control systems . . . . . . . . . . . . . . . . . . . . 4.2Emissions. . . . . . . . . . . . . . . . . . . . . . . . . . 1.6

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . $72.9

SOURCE. F. E McLean, Working Paper for OTA, Mar 15, 1979.

Research has concentrated on propulsion,structures, materials, and aircraft and airframesystems technology that might be applied to anyAST. At this point in time there are no specificaircraft designs. The results so far indicate thatrather impressive improvements over the 20-year-old technology of the Concorde now ap-pear possible. For example, new wing config-urations have been tested in wind tunnel testsand have indicated lift-to-drag ratios above 9,which would allow approximately 20-percentmore efficient operation than the ratio of theConcorde’s wing in supersonic cruise. In thestructural area, NASA officials say the most ex-citing development has been the application offinite-element modeling and advanced computa-tional methods to the design of large aircraftcomponents, allowing for a reduction in designtime from 3 months to 1 week. This not onlypermits rapid analysis of various models but of-fers promise of lower development costs.

NASA’s studies performed with the assistanceof aircraft manufacturers show that superplasticforming and concurrent diffusion bonding of ti-tanium may be able to reduce the weight of air-craft structures by 10 to 30 percent and, at thesame time, achieve cost savings of more than 50percent. Various forms of high-temperaturepolyimide composite structures have been in-vestigated and they show even greater weight-cutting potential.

Variable= Cycle Engine

As seen in table 2, a major portion of the SCRprogram has been devoted to propulsion tech-nology. These investigations have producedconcepts for a variable-cycle engine able to varythe airflow at different power settings. Theengine may be able to operate at near optimumfuel efficiency while cruising at either supersonic(turbojet) or subsonic (turbofan) speeds. Be-cause the engine’s internal configuration allowsthe exit nozzle to move and alter the exhaustvelocity, it also has potential for reducingsideline noise at takeoff and landing. In addi-tion, an indicated greater combustor efficiencymay be able to reduce nitrogen oxide emissionsby more than 50 percent, thereby cutting theamount of atmospheric pollution.

Presently within the aerospace industry thereis considerable optimism about the engine.Many experts feel that, should the engine proveout in a development and test program, it wouldbring a second-generation supersonic transportmuch closer than is generally realized.18 T h eengine’s promise is twofold:

1.

2 .

There is a possibility the engine may beable to meet the Federal Aviation Regula-tion part 36, stage 2 noise rule which wasestablished in 1969.If able to operate optimally at both sub-sonic and supersonic speeds, the enginewould enhance the prospects for integrat-ing an AST into regular airline route

18C. Driver, “Advanced Supersonic Technology and Its Implica-tions for the Future, ” paper presented to the Atlantic AeronauticalConference, Williamsburg, Va., Mar. 26-28, 1979.


structures, as opposed to the limitedroutes flown by the Concorde. For exam-ple, it would become possible to originateAST service to London or Tokyo in Chi-cago, Denver, or Dallas. The over landlegs would be flown subsonically and thenthe AST would switch to supersonic cruiseoverseas. In theory, this extra utilitywould greatly improve the sales potentialfor the aircraft. But it still would havehigher total operating costs than an ad-vanced subsonic aircraft.

Technology Validation Program

In August 1979, in response to the House Sci-ence and Technology Committee, NASA out-lined possible plans for technology validation,which were identified as focused initiatives, in anumber of aeronautical fields. 19 The completionof generic research in technology validationwould be a necessary step in the future develop-ment and production of an AST. In supersoniccruise research the plan concentrated on propul-sion, airframe, and aircraft systems technology.The propulsion part of the program would bebroadened to include research on a variable-flow system and an advanced core engine sys-tem that would be integrated with the variable-cycle experimental engine. The aim would be toproduce design options for an array of super-sonic aircraft applications, plus potential mili-tary applications. The airframe technology pro-gram would concentrate on nacelle/airframe in-tegration and suppression design methods, anddesign and high-temperature structures prob-

““Potential Future Initiative Directions in NASA AeronauticsPrograms, ” Office of Aeronautics and Space Technology, Na-tional Aeronautics and Space Administration, August 19791

lems, including the selection, fabrication, andtesting of titanium and composite materials.The aircraft systems technology effort wouldidentify those portions of the engine and air-frame programs requiring inflight investigationand validation. Accomplishment of these objec-tives would be expected to take up to 8 yearsand would bring the SCR program throughtechnology validation leading toward “technol-ogy readiness, ” regarded as a decision point onwhether the aerospace industry would considerfurther development of an AST feasible. Thereis presently some question whether the aero-space industry on its own would be willing atthese decision points to initiate activities leadingto full-scale production.

The proposed program would cost $662 mil-lion (1981 dollars) over an 8-year period, as op-posed to an alternate program offered by NASAin 1978 ,20 which was priced at $561 million(1979 dollars) over a similar 8-year period. Inaddition, NASA also prepared a $1.9 billionplan (1977 dollars) in 1977 which would havesustained full competition in the U.S. industryand would lead directly to “technology readi-ness.” 21 These three plans have raised a questionfor Congress as to what is the proper level ofFederal support for supersonic research, becauseany one would mean a substantial increase overthe approximately $10 million a year that hasbeen invested in SCR since 1971.

‘“”A Technology Validation Program Leading to Potential Tech-nology Readiness Options for an Advanced Supersonic Trans-port, ” Office of Aeronautics and Space Technology, NationalAeronautics and Space Administration, September 1978.

“’’Program Options for Achieving Advanced Supersonic Trans-port Technology Readiness, ” Office of Aeronautics and SpaceTechnology, National Aeronautics and Space Administration,September 1977.

PROSPECTIVE ISSUES

The issues surrounding the development of an technically feasible in view of the environmentalAST, including the technical difficulties, have objections and economically viable from an en-been given a considerable amount of study by ergy standpoint.the aircraft industry both here and abroad. Thecollective judgment on both sides of the Atlantic One question concerns the degree of technicalappears to be that more intensive generic re- sophistication an AST should achieve. Essen-search is needed to determine whether an AST is tially there are two choices, which are the sub-


ject of the analysis in chapters IV and V: 1) a200-passenger, Mach-2 aluminum aircraft witha design superior to that of the Concorde whichcould be introduced around 1990 and 2) an ad-vanced titanium aircraft capable of carrying 200to 400 passengers at speeds of Mach-2.4 or high-er at ranges of up to 5,500 nautical miles.

In the United States, the aviation communityappears to be persuaded that the more advancedversion has the best chance of meeting the de-mands of the marketplace. There is guarded op-timism that, in terms of development costs, op-erating expense, and market potential, such anAST could be made a commercial success. Thetechnological problems of aerodynamic and en-gine design, structural materials, and aircraftrange and payload are regarded as not insur-mountable. It is believed that such effects asnoise, emissions, and fuel use can be held withinacceptable limits through adequate R&D ef-forts.

Beyond these concerns there are issues of pub-lic policy involving value judgments and alloca-tions of costs and benefits among individualsand segments of society. Energy consumption,environmental effects, costs of the program tothe public, and societal benefits have to be ad-dressed in the debate over whether or not theUnited States should continue to support super-sonic research and at what level of funding.

The issues are not new. They were raised inconnection with the Concorde and the SST.Back then, proponents emphasized such advan-tages as contributions to national defense, bal-ance of trade, and the health of the aerospace in-dustry. The arguments against the Concordeand the SST centered on the high cost to tax-

payers, noise in the vicinity of airports, sonicboom, air pollution, potential harm to people,and climatic effects because of changes in theupper atmosphere. It can be expected that theseissues will arise again in connection with theAST, although perhaps not in the same form orwith the same emphasis.

There is also a more comprehensive set ofissues to be addressed—issues that concern pos-sible choices between supersonic and subsonicaircraft. Regardless of whether an AST is devel-oped, the world market for advanced subsonicaircraft over the next 30 years is expected to belarge, perhaps up to 12,000 aircraft to replaceolder subsonic aircraft in the fleet and to accom-modate the growth in travel demand. 22 Histori-cally, the United States has been the principalsupplier of passenger aircraft for the world mar-ket (as of 1978, over 80 percent of the passengeraircraft in the free world were of U.S. manufac-ture), but there is concern about the ability ofthe U.S. industry to sustain this market suprem-acy in the face of growing competition fromforeign government-industry consortia, such asthat producing the A-300 and A-310. This raisesa question as to the long-term importance ofsupersonic technology to a competitive andviable domestic aircraft industry and a favor-able balance of trade. An allied issue is themagnitude of U.S. Government support to theaircraft industry in the interest of optimizing theprospects for long-term growth and to main-taining a major U.S. share of the world aircraftmarket.

ZZOTA Working paper, Working Group A—Advanced High-Speed Aircraft, Boeing Commercial Airplane Co., January 1979.


These U.S. manufactured aircraft are serving worldwide fIeets

advanced high-speed aircraft: the next 30 years

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