The gate studies: Assessing the potential of future small general aviation turbine engines

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, ASA Technical Memorandum 79075 ^E N THE GATF. STICIES: %'7q-15958 (NA7-A-TM-79075) ASSESSING THE PCiENTIAL OF FUTURE. SMALL GENERAL 4VIATION TURBINE ENGINES (Nk5A) C'SCL 21E Jnclas 24 u HC A02/MF A01 63/07 13784 THE GATE STUDIES - ASSESSING THE POTENTIAL OF FUTURE SMALL GENERAL AVIATION TURBINE ENGINES U rJ N 616, William C. Strack Lewis Research Center Cleveland, Ohio TECHNICt. f. 0A PER to be presented at the International Annul Gas Turbine Conference sponsored by the American Society of Mechanical Engineers Swi Diego, California, March 11-15, 1979

H THE GATE STUDIES - ASSESSING THE POTENTIAL OF FUTURE SMALL GENERAL AVIATION TURBINE ENGINES W. C. STRACK Read, Propulsion Section.

NASA Lewis Research Center Cleveland, Ohio 44135 ABSTRACT cel 450 flights since 1973 and as many as 600 com- munities lost service. Further route trimming in ex- Four studies have been completed that explore pected since the CAB'a new deregulation policy facil- the opportunities for future General Aviation Turbine itates more service cuts. These trends together with Engines (GATE) in the 150-1000 SNP class. Detroit large technological improvements (notably in avionics) Diesel Allison, Garrett/AiRenearch, Teledyne CAE, and have been the major factors in establishing general Williams Research participated along with several aviation as a vital link in our air transportation nr airframers. These studies forecasted the potential system. Consequently, factory billings have exper- m impact of advanced technology turbine engines in the ienced rapid, steady growth - reaching $2 billion in ON post-1988 market, identified important aircraft and 1978 (incl. helicopters), or 55% of the air transport missions, desirable engine sizes, engine performance billings, as shown in Fig. 1. Over $600 million of and cost goals. Parametric evaluations of various thin total is exported.

engine cycles, configurations, design features, and A persistent myth holds that civil aviation is advanced technology elements defined baseline con- made up almost entirely of passenger carrying air- ceptual engines for each of the important missions liners with a sprinkling of light aircraft belonging identified by the market analysis. Both fixed-wing to a few privileged private owners luxuriating on and helicopter aircraft, and turboshaft, turboprop, weekends. On the contrary, 98% of the civil fleet is and turbofan engines were considered. All four con- made up of general aviation aircraft which perform a tractors predicted sizable performance gains (e.g., broad variety of vital public services: flying peo- 20% SFC decrease), and three predicted large engine ple and freight, surveying and mapping natural re- cost reductions of sufficient magnitude to challenge sources, seeding and treating crops, patrolling pipe- the reciprocating engine in the 300-500 SID? class.

lines, forests and fisheries, firefighting, mineral Key technology areas were recommended for NASA sup- prospecting, rescue and ambulance services, traffic port in order to realize these improvements.

control, and other utilitarian services. Only 5% of the genera] aviation operations involve sport flying INTRODUCTION while 72% of the flights are for business and com- mercial purposes. Business use is increasing as com- General aviation's spectacular growth in the panies have found that owning planes to transport key 1970's has.been propelled by significant changes in people and freight can be cheaper and moreconvenient the nation's transportation system and in corporate than using airlines. Another myth is that the bus- demographics. More and more American businesses are iness sector is made up solely of highly paid execu- expanding into less yspulated areas where tax rates tives flying opulent business gets. 6.uch of the usage are low and working r,onditiona are good. Reaching is for middle managers and equipment-maintenance peo- these small-town areas Is difficult without small ple. About 92% of the business fleet in piston-engine aircraft and is aggravated by the airlines' con- powered - only 8% is turbine powered.

tinuing trend to cut back on leas profitable routes.

As shown in Fig. 2, all categories, except agri- OPEC's oil embargo persuaded the major lines to can- cultural, share approximately equally in this $2

- Search for high risk technologies yielding billion/year market in terms of net factory billings, high payoffs that could be incorporated,into However, turbine-powered aircraft sales are increasing 1990 time framo engines at a much faster rate than the reciprocating-powered - Emphasize economics of aircraft ownership models, The turboprop segment in particularly strong - Involve airframsro for applications definition with a 9.22 10 - year unit annual growth rate and a and benefit assessments 20 times as 262 increase in 1978 alone. Yet more than Although these tasks were basically carried out se- many piston-powered airplanes are U.S. produced each quentially, iteration between them was necessary since 000 compared to turbines in year (over 655 1977).

engine cost and performance are needed in Task I but Coupling this with the fact that all sectors of avi- are not firmly established until the end of Tasks II ation have already transitioned to turbine power and III. Conversely, the engine sizes, engine re- (Fig. except these small airplanes, questions 3) quirements and production volume information pre- arise as to why this most numerous segment has not dicted in Task I in needed in Tasks IT and III to yet transitioned and what are the prospects that it properly conceptualize an engine and to obtain engine will sometime in the future.

coat, Recognizing that general aviation in an impor- tant and rapidly expanding industry and mindful that TURBINE ENGINE OPPORTUNITIES NASA sponsored engine research has been almost ex- alusively limited to large aircraft, the HASA Lewis The most fundamental objective during these Research Center decided to explore the opportunities iterations was the determination of superior op- time frame turbine engines applicable to the for 1990 portunities for advanced turbine engines. Since NASA smaller end of the general aviation spectrum. This Set the contractors make their own independent se- exploration was initiated in 1977 with four contracted lections on this broad issue, it is not surprising studies and one in-house study collectively known as that some diversity of views emerged. Allison's study 'GATE' - General Aviation Turbine Engine - with a focused on a relatively sophisticated, high- 1000 SHP upper limit for turboprops and turboshafts, performance engine concept that would compete well and a 1500 lb thrust limit for turbofans. This paper against current turbine engines, but was too expensive presents an overview of these studies which are in- to penetrate deeply into the reciprocating market.

dividually documented in much greater detail in sep- The other three contractors argued or. the basic of arate reports.

their analyses that the most challenging and important opportunity involved addressing the issue of turbines THE 'GATE' STUDIES APPROACH versus recipe in the size class now dominated by recap engines. Overcoming the turbine engine cost The four contractors were Garrett/AiResearch, barrier is clearly a requirement in this case, and Teledyne CAE, Williams Research, and Detroit Diesel these contractors devoted their efforts to finding Allison. Each spent 10-12 months of technical effort acceptable ways of meeting this difficult challenge.

independently addressing the four Tanks shown in Fig. 4. The first tank was to forecast a 1988 market SELECTING All ENGINE FOR LIGHT AIRCRAFT scenario in order to identify the aircraft and mis- sions likely to be suitable for advanced small turbine Since Teledyne, Williams, and Oarrett all pursued engines. Desirable turbine engine sizes and require- the low .ost versus recip theme, a few comments re- ments were established for both fixed and rotory wing garding this issue are offered. Piston engines aircraft. In Task TI advanced future engines were totally dominate, the market up to 400 SHP due almost ultimately selected and evaluated for each of the im- :1 cost advantage over turbine en- entirely to their 3 portant aircraft/mission categories identified in gines in a very coat sensitive market. Yet turbine Task I. This was done by subjecting baseline engine engines possess many supe:ior qualities: three times definitions to numerous cycle, configuration, and ad- lighter, much lower maintenance, less installation vanced technology tradeoff analyses. During these penalties, higher reliability, much lower vibration, broad-scope tradeoff studies, the 'optimum engine' noise and emissions, multifuel capability, and a bet- definitions were selected on the. basis of key air- ter safety record. These highly desirable turbine craft economic criteria such as aircraft acquisition qualities must be weighed carefully in selecting the cost, operating cost, and total cost of ownership.

most suitable power plant type. The challenge is to Concurrently, a set of advanced technologies was capture these acknowledged benefits by lowering en- screened to identify those technologies with the gine cost sufficiently to tip the scales in favor of greatest potential payoffs.

depicts the current situation and turbines. Fig. 5 Then in Task III theset of optimum engines de- indicates that, in addition to the engine cost dis- single fined in Task II was modified such that a advantage, turbine engines also burn more fuel.

common core could be utilized for all sizes and types Turbine SFC's are about lb/RP-hr com- 0.55 - 0.65 of engines comprising the Task II set. This 'common tared to 0.40 - 0.50 lb/HP-hr for recipe. However core' ;oncept vas then evaluated for additional eco- comparing bare SFC's is often misleading unless nomic benefits. Finally, in Task IV, each contractor other factors such as installation lasses, fuel type, recommended a technology program plan to develop and r and engine weight are also compared. As shown in demonstrate t.ae key technologies he previously installation losses for recipe reduce its Fig. 6, identified as being essential to his conceptual en- cruise SFC advantage considerably. Cylinder cooling gines.

losses can amount to 102 of the total aircraft drag.

Within this basic framework each contractor re- Nacelles for the larger recip engines produce more ceived only very broad guidelines from NASA which drag. Ai:d, at least theoretically, recip propellers permitted each to emphasize aspects considered im- are less efficient due to their thicker structure re- portant in his judgement. These guidelines were: quired to withstand the high vibratory stresses - Consider engines up to 1000 SHP (or 1500 lb caused by the pulsating power generation. process.

thrust for turbofans, but emphasize the less Furthermore, turbine fuel contains 102 more energy/ SHP class than 600 s gallon and costa about 102 less - for a 202 total

F' coat advantage -ver Avgaa. Also, the 3tl weight ad- Allison'a them* differed in that they preferred vantage of turbines saves fuel since it permits a a relatively sophisticated high-performance engine.

significantly smaller aircraft size. The combination They concentrated mainly on a turbine engine which of these factors neutralizes the apparent recip SFC produced better fuel economy at Sower weight and re- advantnge in many applications. Thus the fuel pen- duced installation volume in comparison with their alty of turbines is more apparent than real. The 3:1 latest production small gas turbine engine. Their cost difference is the only true barrier to its wide- GATE conceptual engine costs more than their latest spread usage in airplanes below 8000 lb grace weight.

production engine which has a relatively large ad- vuotage in price primarily due to long production ex- MAJOR ENGINE IMFROVEMEIITS perience. Their theme, then, was to determine if the performance advantage of a new high pressure ratio gine Size En air-cooled engine was sufficient to offset the price All of the contractors chose baseline engine advantage acquired by engines with long production sizes within a band from 375 to 565 S11P. These sizes runs (e.g., their 250 aeries).

were chosen principally on the basis of the attrac- tive market opportunities, but, to a leaner degree, THE EFFECT ON AIRCRAFT ECONOMICS were also biased away from the 800 SIN' class already being addressed by the U.S. Army in its Advanced The impact of using GATE technology engines on Te c hnology Demonstrator Engine (ATDE) program.

aircraft economics was analyzed by each company with assistance from airframers, The cost analyzes in- Performance volved flying synthesized GATE-powered aircraft over After considerable tradeoff analyses wherein en- typical missions to determine fuel consumption and gine performance and weight were traded for engine aircraft sizes. Aircraft acquisition and operating cost, all study participants independently concluded coat models were then exersized to determine these that advanced component technologies can yield 20".

costa plus the total coot of ownernhip based on re- BSFC improvements relative to currently produced en- sale after several years of non-revenue service.

gines in the 400 SHP class. As shown in Fig. 7 this Table 1 illuatratea a typical aircraft/mission cate- would extend the flat BSFC trend line down into the gory breakdown resulting from the market analyses.

300-400 SHP range and represents a very substantial The aircraft and missions at the small sizes range performance gain. The trend toward better small en- from 2-place trainers up to 12-place heavy twine, plus gine fuel economy is also bolstered by the Army^a ag-planes and light helicopters. Only modest changes ATDE engine program. The Army has established a goal in aircraft capabilities are forecast during the next of 0.55 SFC at 480 SHP for an 800 sHP class turbo- decade except for the hi-performance single-engine shaft engine, It was also concluded that turbofans category whet . a new demand is emerging for pres- were not competitive with turboprops since they had surized, high-altitude flight using sophisticated much higher fuel eonoumption in addition to greater avionics such as weather radar. Itot surprisingly, weight and cost. This is not surprising in view of the GATE screening process eliminated the smallest the low flight speed requirements (less than 300 category as an attractive turbinization candidate.

knots) forecasted for GATE applications.

These categories differed somewhat among the con- tractors and each selected 2 or 3 representative Engine Cost categories for detailed application assessment.

While BSFC gains are important, even more signif- A typical example is given in Table 2 that il- icant are the forecast engine cost reductions that lustrates the large economic improvements of GATE accompany them. The average cost reduction of the technology turboprop-powered aircraft compared to three "low-cost" engine designs is estimated at 505. recip-powered aircraft. The example is a light un- This is the inherent coat reduction through applica- pressurized twin which is resized for several alter- tion of GATE advanced component and manufacturing native powerplant options to fly identical missions technologies and based on current production rates cf with name-technology airframes. Only very modest im- about 500 units annually per manufacturer, Once the provements result from postulating an advanced recip cost barrier is breached by such a magnitude, the with 109 better SFO than. current recipe. And a cur- market analyses' cost-demand relationships dictate rent technology turboprop (e.g., scaled-down T700 that much greater sales rates are triggered. This, rather than existing production engine technology) is in turz., opens up the possibility of a dedicated only a standoff in economic terms. But an advanced manufacturing facility which would reduce engine technology turboprop aircraft would be 20% cheaper costs even further. Garrett and Williams foresee to own, burn 8% less fuel and cost 14% les3 to pur- 6000-80oo units/year per manufacturer and a total chase than an equivalent aircraft powered by today's coat reduction of about 60% while Teledy„e foresees recip engines. It is even 15% cheaper to own than about 16 000/year and a correspondingly greater re- the postulated advanced recip aircraft.

duction. These cost reductions are shown in. Fig. 8 Two other examples are shown in Table 3 where a which also contains a sketch of each company's base- maximum payload comparison is done on a. retrofit line engine concept along with other pertinent data. basis for existing airframea instead of all new air- These GATE engine coat predictions are compared frames as in the previous figure. Here gross weight with current engine costs in Fig. 9. Here the three is fixed and the retrofitted turboprop is derated low-cost GATE engines are plotted twice. The upper from 39G S11P to 352 SUP for the twin-engine Aerostar square represents current turbine production rates of 601P and to 305 SHP for the single-engine Mooney 201.

about 500 units per year per company, while the lower The GATE turboprop retrofit results in faster climbs square accounts for the additional effect of high to higher cruise altitudes and far greater ranges with volume production. Clearly neither advanced tech- full payloads. GATE, fuel economy is equal to the nology nor high production volume alone can push the recip version for the smaller Mooney and 54% better turbine engine into a solid competitive position with in the Aeror rar case. Productivity is improved by recips. It taken both factors, but the key that un- 12% for the Mooney and 62% for the Aerostar.

locks this potential is advanced technology (described 'R later).

The results shown in Fig. 10 of all the low-coat ogien. But due to the Phase bulk of concepts in- theme application studies reveal important coot of volved and their often proprietary nature detailed ownership trends. An expected, larger aircraft discussion in avoided.

benefit more from GATE turbinizmtion than smaller air- craft, Light to medium weight twino show impressive Teledyne. Teledyne's general approach is to 20 to 33% improvements. Even medium performance utilize the higher component efficiency levels made singly-engine models in the 200-IIP class reap come possible through advanced technology to drastically reduce the parts count while simultaneously retaining economic benefit. The conclusion to be drawn in that despite the fact that the case for turbine engines is high performance. For oxample, whereas a typical predicated on its numerous non-economic advantaged 700 SHIP current production engine might consist of (e.g„ safety, comfort, reliability and muitifuel two centrifugal compressor stages and 3 axial turbine capability), a very important economic bonue exists stages on two shafts, their 335 GBP conceptual GATE engine contains only a single, uncooled radial tur- which bolsters their position considerably.

Fig. 11 summarizes both the economic benefits bine connected to both a single centrifugal compreo- and the other desirable qualitieu (size Independent) cor and the load with a single shaft. F;'.g. 12 illuo- of GATE technology engines an acnenned by Garrett, trateo this approach and the amount of engine coot Teledyne, and Williams. The economic incentives savings attributable to each item. The key component range from strong for twins, to moderate for re- in this approach is the high temperature (2250 0 F mat) uncooled radial turbine. It is predicated on tractable singles, to neutral or negative for fixed the use of high tip speeds (2500 ft/a) and advanced gear singles (not nhown). This includes signifi- cantly lens fuel burned in concert with the national materials - rapid solidification rate powdered. met- energy policy. Similar economic benefits were deter- allurgy. This is a high risk technology to be sure, mined in Allison's high-performance theme except that but it also has the high potential payoff of a 16: the benefits occur only in comparison to current engine price reduction, The second largest price turbine euginen - with 20% lower cost of ownership drop comes via the replacement of hydromechanical due to lower SFC, lower weight, and longer overhaul controls with electronic controls. This is actually periods. judged to be a relatively low-rink item and capital- izes on the low-cost electronic controls technology IMPACT OF GATE ON MARKET anticipated for the automotive industry. A total engine cost reduction of 49"n is estimated through ad- vanced engine technology alone.

Raving determined the turbine-powered aircraft performance and economic characteristics, the Task I In addition to this savings, an additional 17% 1988 market forecasts were updated to reflect the savings is estimated to be achievable through ad- computed aircraft benefits. Representative results vanced fabrication methods and materials. The powder are illustrated in Table 4 assuming instantaneous en- metal/squeeze-cult compressor rotor and other tech- gine maturity. Substantial turbine penetration into niques defined on the lefthand side of Fig. 13 become the reciprocating domain is forecast with spectacular economically attractive at production. rates in excess gains in sales volume and market value. In this of 2000 units annually.

Teledyne example, 31450 GATE engines are sold annu- Finally, and as an example of the Task III com- ally with a market value of $120 million per company mon core evaluation, the righthand side of Fig. 13 if two companies split the market about equally. illustrates one example solution to the problem of Market potential of this magnitude commando serious accommodating various engine size and type require- attention. The other compa,lys l forecasts are less ments. The simple 335 ESHP design is uprated to 565 optimistic bit still impressive: Garrett, 15120 ESHP through the addition of an axial compressor and total units/yrar; Williams, 20500; and Allison, 2250. an axial turbine stage plun a duplicate set of gears to handle the increased loads (as shown in the dia- Anot:,er common result is that substantially greater fixed-wing market potential exists than gram). Thus cost in only added when needed and rotory-wing. A direct outcome of this result was affordable. Preliminary analysis also indicates that the preference for a single-shaft engine configura- one satisfactory way to obtain a lower power version tion by both Teledyne and Williams to save cost. (265 ESHP) is through the addition of inlet guide While the previously discussed coat of ownership vanes to reduce airflow while maintaining constant turbine inlet temperature. Lastly, since helicopter savings accrue to individual owners, cummulative fleet savings is a more meaningful parameter when ,fudging turboshafts are preferably free turbine configura- the overall impact of GATE technology engines. Tele- tions, a free turbine may be added to the baseline dyne estimates that if GATE engines attained sales design (. and gearbox removed) to obtain commonality of maturity within years, the average total GATE- core parts over a complete family of engines. The powered fleet savings would amount to nearly $350 extra cost of the free turbine version is ,fudged a million per year. reasonable compromise in view of the much more num- erous airplanes and the reduced emphasis on cost for Advanced Technology helicopters. The power range investigated by Tele- dyne in this approach was wider than the others and The foregoing shows that the potential improve- ments in small turbine engines could lead to dra- helps to explain their larger market expectations.

matic aircraft benefits and a major shift toward turbinization of the general aviation fleet. But Williams. Williams Research advocates a unique what does it take to unlock this potential? The in- approach that begins with known low-cost manufactur- gredients of the hypothetical assault on the all- ing techniques and attempts to achieve acceptable en- important cost barrier consisted of: innovative ad- gine performance within the geometric constraints im- vanced component and manufacturing technologies, posed by such techniques. The concept (Fig. 14) in- judicious engine design concepts, and parts common- volves design stresses about 1/2 of conventional levels which leads to moderate turbine inlet temper- ality over a wide range of engine sizes and applica- ' tions. This section will discuss the individual atures (e.g., 1850 0 F) in an uncooled engine with extremely high time between overhaul (never needs an approaches advocated and identify the key technol- h

overhaul). Further downutrem could be versions util- 2-opool design with two centrifugal compressors Wfa izing advanced, high temperature materials to achieve P/P), two cooled axial gas generator turbines, and 350' F higher turbine inlet temperature, still un- two uncooled axial power turbines. While come cost cooled and fully compatible with low cost manufactur- saving features were identified (e.g., composite ing techniques. The manufacturing techniques for gearbox housings and shafts, powdered metal gears, these low-strewn, low-speed designs lend themselves ceramic turbine vanes and tip shrouds) moat of the to the choice of multi-stage axial compressors and technologies recommended by Allison were of the tradi- turbines which is seemingly expensive in comparison tional component performance improvement variety, to aingle-stage radial components. However, by re- Interestingly, the resulting improvements in engine stricting the blade geometry in order to capture the performance yielded lower aircraft gross weight and ultra-low coot manufacturing advantages of using reduced airframe costa such that 10 to 15H reductions simplified blade shapes and attaching them to a in aircraft ownership costa were realized in compari- single hub at one time, significant coat savings are son with their latest engines with long production feasible. The resulting constant-chord, constant run cost advantages.

airfoil section, constant camber and uniform twist configuration departs radically from traditional Recommended Technology Programs (Task IV) concepts in its attempt to properly trade off per- As a result of their studies, each contractor formance for cost. Some limited hardware work has recommended a 5-year technology program to NASA that already been done with these manufacturing techniques would establish the technical readiness and economic in conjunction with the WR-33 limited life expendable validity of his concept, A general picture of these turbojet. To date, the results have been encourag- programs is given in Fig. 16. It consists of several ing but, of course, are very preliminary.

years of component technology efforts followed by ex- perimental core and engine (not a production proto- Garrett. Garrett's approach is generally simi- type) phases which integrate the various components lar to Teledyne's, namely, design a simple engine by into a matched system. The key technologies required sacrificing some performance and weight (mainly to obtain the large estimated benefits are definitely weight) to obtain fewer and less difficult to manu- high-risk types beyond those expected to become avail- facture parts. The baseline design differs from able through ordinary private funding sources. Hence Teledyne's in that Garrett selected a two-spool de- the likelihood of actually experiencing these benefits sign with a 2-stage axial power turbine for all sizes depends critically on the degree of government- and applications. It also differs considerably in sponsored support.

the kinds of technologies required to achieve low cost (Fig. 15).

The key technology is a cooled SUMMARY radial gas generator turbine constructed of many photoetched laminates, activated-diffusion bonded General aviation already constitutes a vital link together for a near net-shape piece. Another im- in our air transportation system and its importance portant technology is the near net-shape single- is expanding rapidly. Yet the overwhelming majority stage centrifugal compressor using powdered titanium of these aircraft have not captured the increased metallurgy.

safety, comfort, reliability, productivity, multi.

Screening assessments of each technology element fuel flexability and emission advantages available were also carried out as illustrated in Table 5.

with turbine engines due to high acquisition cost in Shown are the fundamental changes in engine criteria relation to piston engines in small sizes. The tech- which ultimately react on aircraft economics for each nological progress in small civil gas turbine engines technology surviving the screening. Only those tech- has traditionally been slower than in large engines nologies that survived are shown here, many others due to the inherently more difficult design problems were considered but rejected. The changes are rela- compounded by a lack of research funding. Despite tive to a hypothetical baseline representing current these impediments, it now news probable that a state-of-the-art technology - i.e., the best turbine proper combination of advanced component technolo- engine that could be built today without GATE ad- gies, improved materials, innovative manufacturing vancements. For example, the current technology engineering, and design simplifications could over- baseline engine would use a cooled, axial HP turbine come the turbine engine cost barrier. The resulting' configuration with inserted blades. But the use of engine improvements are so major that the turbine a cooled, radial turbine of laminated construction engine could be expected to successfully challenge could by itself reduce engine cost 22$, 8FC 8%., the reciprocating engine in all sizes above 250 SHP weight 7%, and airflow 10%.

(Fig. 17). The acknowledged attractive features of The 3 righthand columns of this table show the turbine engines could in fact usher in a new era of overall cost saving for a total fleet of GATE- dramatically improved business/commercial air trans- powered medium pressurized twins over a 20 year per- portation.

iod and the estimated development cost in order to rank the technologies on a benefit/cost ratio basis.

The actual development cost estimates are not shown here (propriety), rather they are normalized such that the total component development cost was arbi- trarily set to $10 million. Although the radial HP turbine technology is twice as expensive as any other element, its high benefit gives it the top priority position.

Allison. As already mentioned, Allison concen- trated on performance, weight, and maintenance im- provements rather than initial cost. Consequently their concept evolved into a . relatively sophisticated

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• VITAL PART OF AIR TRANSPORTATION SYSTEM 981. OF AIRCRAFT (170 0001 96`k OF AIRPORTS X13 000, 381% OF INTERCITY PASSENGERS 1110 millionlyr) • INCREASING IMPORTANCE OF BUSINESS AIRCRAFT INDUSTRY'S DECENTRALIZATION TREND AIRLINE ROUTE TRIMMING TREND AIRCRAFT TECHNOLOGICAL IMPROVEMENTS • FACTORY BILLINGS UP SHARPLY $? bil' i on SHIPPED IN 1978 $600 million EXPORTED IN 1978 BOTH RISING AT 15 to ?OVyr r- 4,0

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CAR GENERAL DERt ULATION 1.0 AVIATION OPEC OR PRICE HIKE 71 72 74 75 70 73 76 77 78 79 80 yr Figure 1. - General aviation is important and expanding rapidly.

nrTr.TKAI, I' UNITS 10 yr RETAII PRICE UNIT FACTORY BILLINGS, $ millions GROWTH RATE, % 400 500 0 100 200 300 I ;Slfy^lE. EN61NE PISTON, .;, 435 13 167 4.3 $15K 100K 389 2 195 4.4 70K 300K MUL f-MIN 9.2 UREO PROP 295 428 !)(W - 2M JET 328 227 6.1 1M 6M TURBOFANS AGRICULTURAL 37 890 6.7 40K - 200K HELICOPTERS, i 454 8.7 50K - 1M $1938 M 17 847 - U.S. general aviation aircraft sales in 1977.

2.

100 p BUS INESSIEXECUTIVF Lj CGMMEF<CIAI TRANSPORTS = w - LIGHT 50 / MILITARY BOMBERS HELICOPTER U, TRANSPORTS, & ? FIGHTERS —.

MEDIUMfHEAVY m HELICOPTERS LIGHT AIRPLANE,, O 1940 19% 1960 1970 1980 Figure 3. - All aviation segments have transitioned to turbine power except light airplaines.

TASK I - MARKET SURVEY (3 mor,thsl FORECAST 1988 MARKET SCENARIO FOR G.A.

ENGINES IN THE 150-it100 horsepower CLASS FIXED & ROTARY WING AIRCRAFT SELECT MAJOR TURBINE ENGINE SIZES AND CONFIGURATIONS DtFINE AIRCRAFT CHARACTERISTICS 112 months) TAFK 11 - BROAD-SCOPE TRADEOFF STUDIES (4 ORECAST APPLICABLE ADVANCED TECHNOLOGY CONDUCT PARAMETRIC STUDY (PERFORMANCE. COST & WEIGHT) SELECT & EVALUATE OPTIMUM ENGINE FOR EACH APPLICATION TASK III - COMMON CORE CONCEPT EVALUATION (1 112 months) EVALUATF THE USE OF A SINGLE CORE ENGINE FOR ALL OR SOMF OF THE TASK I I APPLICATIONS TASK V TECH N OLOGY PROGRAM PLAN DEVELOP A PLAN TO DEVELOP AND DEMONSTRATE ADVANCED - 'CHNOLOGIES FOR SMALL TURBINE ENGINES Figure 4. - Gate study approach.

I \

`^ggOE T I R ^ I vIBRATIONS RELIABILITY MULTIFUEI SAFETY WEIGHT EMISSIONS NOISE FI^EL MAINTENANCE INSTALLATION LOSSES ENGiNE COST TURBINE ADVANTAGES TURBINE DISADVANTAGES Figure 5. - Current engine selection for light airplanes.

;AL PAGE Li .

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WEIGHT 2.5 ro RECIP 2 , 0 TURBO-RECIP ^ 18 000 (t 225 m ;^ m

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W 1.0 TP (TURBOPROP) "—' ^ .45 - - .5 - - I - —^ v . 35 0 200 400 600 0 200 400 RECIP TP COOLING LOSS 10% 0 NACELLE DRAG 8% 4% COST - 1977 OEM W 5 PROPELLER 77 .86 .88

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31 T ° Ee 50— RECIP RECIP 3; .31^_--- wwor -0 -J 600 900 0 700 400 0 300 600 SHP Figure 6. - Current small engine trends.

SEA LEVEL

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C20B T PE 331 ^ C30 C28B ` .58 - LTS 10 , \1 v' .54 50 501 D 22A 1 "^` CURRENT T700 T701 •46 GATE I I I i I .42 —I - 0 2 3 4 6810 SH PI1000 Figure 7. - Gate SFC improvements.

TELEDYNE GARRM ^— 419 shp 565 shp 9: l pr 11. 3.1 pr 22000 F ^^ 22500 F 0.44 lb/hp 0.36 lb/hp W ILL IAMS ALLISON 376 sh

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500 shp 13` cr 12, 8:1 pr 14:1 pr i –^ _ 18500 F _^ 22000 F 0.48lb/hp

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1.10 CURRENT TECHNOLOGY R EL.

ENGINE COST 5 ALLISON GATE GATE TECH.

TECHNOLOGY & DED. MFG.

PLANT Figure 8. - The conceptual gate baseline engines and forecasted costs.

^, AV'V, 15 • CURRENT TURBOPROPS H200/yrl° rr' \j rt.1.11`Y `TOTAL U.S. PRODUCTION AI I )SON GARRETT * TELEDYNE

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CL GATE 50 WmS RATE x t T CURRENT 1--500/yr/Co. I i TURBORECIPS POI EN11Al (6 - 1600(YyrlCo. 1 RECIPS 125000/yr) _----

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100 200 300 400 500 600 700 800 900 THERMODYNAMIC SHP Figure 9. - Gate engines are forecast to be nearly cost competitive with reciprocating engines.

knots n, m.

GARRETT 0 MED. PRESS. TWIN 18 000 240 840 n LIGHT TWIN 10 000 225 1100 O TELEDYNE 6-9 PLACE TWIN 1R 000 250 1200 • 4-PLACE UTILITY 10000 170 700 0 ► WILLIAMS 6-PLACE AEROSTAR 601 TWIN (RETROFIT • 4-PLACE MOONEY 201 (RETROFIT) a_

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-- SINGIJ 5^ Z o W F- LD 0) 500 200 300 SHAFT HORSEPOWER FOR RECIP VERSION Figure 10. - Gate powered aircraft have lower cost of ownership than equivalent recip powered air- craft.

4• "r`r TS TURBOPROP POWERED PRESSURIZED TWIN AND LIGHT TWIN TURBOPROP POWERED HEAVY AND LIGHT RETRACTABLE SINGLE ENGINE 20- 25% 10 -15% LESS GROSS WEIGHT 10- 15% 0- 15% LESS FUEL BURNED 10- 15% LESS INITIAL COST 15 - ?>°lo 7 - 15% LESS OPERATING COST 30 - 40°<0 25 - 35% 8 - 15% LESS LIFE-CYCLE COST HIGHER RELIABILITY GREATER SAFETY AND COMFORT QUIETER AND CLEANER MULTIFUEL CAPABILITY Figure 11. • Beoefits relative to current reciprocating engine.

W ADVANCED TECHNOLOGY LESS THAN 500 hp — r GA TE \ CURRENT TECHNOLOGY MORE THAN 500 hp ENGINE COST SAVINGS, percent 2 CENTRIFUGAL COMPRESSORS 1 CENTRIFUGAL COMPRESSOR 1 RADIAL TURBINE 3 AXIAL TURBINES HYDROMECHANICAL CONTROLS ELECTRONIC CONTROL VAPORIZING PLATE COMBUSTOR ATOMIZING COMBUSTOR 8 112 PRI1900P F CYCLE 9.0 PR12250P F CYCLE Figure 12. - Advanced technology investment reduces engine price (teledyne).

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ADVANCED FABRICATION METHODS & MATERIALS POWDER METAL TURBINE ROTOR POWER METALISQUEEZE CAST COMPRESSOR ROTOR POWDER METAL GEARING `., TOTAL COST REDUCTION 17. 7% DIE CAST ALUMINUM HOUSINGS -j COMMON CORE APPROACH 2 -- - `I r - 38.

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12.4 16.4

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lb Ibis 3-OEM ESHP ESFC 2.9 7 830 BASELINE 565 203 0.46 335 .52 2.2 5080 REMOVE AXIALS 172 & GEARS .54 5 080 ?65 17? 1.8 ADD IGV & REMATCH .46 18 ?30 ADD FREE 565 178 2.9 TURBINE Figure 13. - Additional engine price reduction concepts (teledyne).

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LOW-COST SIMPLIFIED BLADE MANUFACTURE II - . MULTIPILL ROW BLADE MANUFACTURE • BLADES IN PLACE AS HUB IS FORMED ALL BLADES. SAME AIRFOIL SECTION CONSTANT CHORD & CHAMBER UNIFORM TWIST DIFFERENT LENGTHS i W 40K CONVENTIONAL HiuH STRESS DESIGNS 30K ,n `" MA 6000E W IN-100 v+ — 20K \ z "' LOW STRESS LOW SPEED ° 10K DESIGNS 1 1 i i 1 1 0 1 1600 1700 1800 1900 2000 2100 METAL TEMPERATURE, of Figure 14. - ;Manufacturing technology areas compatible with restricted aerodynamic shapes (Williams).

DESIGN

I

SIMPLICITY

X L -^] 17

MINIMIzi COMPONENTS, BEARINGS, FRAMF S NET SHAPE INTEGRAL COMPONENTS P E' IOW-CO ST COOLED TURBINE Figure 15. - GATE approaches to low cost IGarrettl.

(1PIGTIIAL PAGE I5 YEAR TASK 3 4 5 ?

DETAILED DESIGN TRADE-OFFS PRELIM. DESIGN AND BASELINE SYSTEM DESIGN DEMONSTRATE BASIC TECHNOL- OGY FOR LOW-COST, HIGH- COMPONE,.r- PERFORMANCE COMPONENTS EARLY D;SCOVERY OF CRITICAL GAS COMPONENT IIJTEGRATION GENERATOR REQUIREMENTS N h a DEMONSTRATE GATE TECHNOL- w • T OGY READINESS AND PER- EXPERIMENTAt W FORMANCE AND PRODUCTION ENGINE POTENTIAL CONTINUING COST/ PERFORMANCE SYSTEM TRADE-OFFS AND UPDATE OF ANALYSIS AND PREDICTED ENGINE AND SYSTEM DEFINITION PERFORMA'.^E AND ECONOMICS MILESTONES ♦ PRELIMINARY DETAIL DESIGN • TECHNOLOGY n FIRST READINESS DESIGN REVIEW REVIEW TEST REVIEW Figure 16. - Candidate gate technology program tGarrett).

• SIMPLER DESIGNS • IMPROVED MATERIALS • HIGHER COMPONENT PERFORMANCE • CHEAPER MFG. TECHNOLOGY • CORE COMMONALITY • LOWER ENGINE COST • LOWER ENGINE SFC • LOWER ENGINE WEIGHT ENGINE COST BARRIER / r CURRENT 1 000 000 4* TURBOPROP POWERED 14001yri RECI P < POWERED a GATE POTENTIAL 116 0001y r) a II 0 200 400 600 800 1000 ENGINE SHP Figure 11. - Gate technology could expand domain of small turbine engines.

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