AIAA -93-3950

TECHNOLOGY ADVANCEMENTS AS APPLIED TO SIX SUBSONIC TRANSPORTS

T. Hoang and D. Soban California Polytechnic State University San Luis Obispo, CA

AI AA Aircraft Design, Systems

and Operations Meeting

August 11 -1 3, 1993 / Monterey, CA For permlsslon to copy or republish, contact the Amerlcan Institute of Aeronautlcs and Astronautlcs 370 L'Enfant Promenade, S.W., Washington, D.C. 20024

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TECHNOLOGY ADVANCEMEh'TS AS APPLIED TO

SIX SIJBSONIC TRANSPORTS

D & l l e SI-g)han* California Polvtechnic State 1 Jniversitv

The following paper presents summaries of six subsonic transports designed by the 1993 seniw undergraduate class at Cal Poly, San Luis Obispo. Advancements in subsonic technologies as applied hy these design teams are discussed. Two of the aircraft were designed to till the 100-150 passenger niche, one aircraft was designed for the mid-class 200-2.50 passenger niche, and one aircraft was designed for the ultra-high capacity 800+ passenger market. The final twu designs were global range military transports.

aerodynamic and fuel efficient configuration. the cost of a new ;urcraft hecomes more economically feasible than improving an existing design.

Twu Cal Poly design team have attempted to offer their version and competitor to this market. The new airframes offer more efficient configurations (larger aspect ratio wings) while decreasing direct operating ccist to the airlines (more efficient propulsion units). In addition. they cater more to passenger comfort hy offering wider cabin and lnrger s a t pitch.

Conticuration - the Weasel Works

Tlie g w l of this design team was simple and Each year, CaI poly San Luis OhisPo chooses s(r;lighttt)fWtd; 1 0 OUtperfOlln its competitor. T h s i WgeL

different aircraft design topic to assign the selli,,r aeronautical engineering design class. This tile topic was exploring the realm of subsonic flight, Four differen1 requests for proposals (RFP) were issued The first w:~s ii small 100-150 passenger 1500 nm range aircraft to succeed the Boeing 737 and McDonnell Douglas D C 9 family of aircraft. Two design teams opted for this challenge. Next was a 200-250 passenger, 5.500 nm range aircraft. One team chose this as their project. A single team also chose to design an ultra-high capacity, 7000 nin aircraft. The final two design teams elected to attempt the design of an 800,000 Ih payload aircraft cap:ihle r i f

traveling 6 0 0 nm, at which time 8% of the pay1o:id is off loaded, and the aircraft returns.

Each of the groups investigated recent advances i n subsonic technologies as they applied to their pnrticulu designs. These advances, along with a hrief summwy ( i f each aircraft and justification for their mission. iue discussed below.

the Boeing 737-500 fzunily (if ;lircraft. The SA-I50 is fairly convention:il ill design (Figure I ) , with ii high i~%pccI rxtio wing :ind the distillctive V-tail contigurati~~n~.

The

Justification

'i' 7 )' < . . - 1.50 pas-

Currently, there are over 2,100 transports reaching their 20th year of service and nearing their average Lifetime limit of 25 years I . within the next decade. more stringent environmental regulations will make it more difficult for airlines to justify the cost of maintaining :ind upgrading this older fleet. So an W P went out to two design team to fill this shortcoming. The W P sripu1;ited that these modern small transport he ahle to cmy I(X1- I50 passengers for 1500 nm.

To meet these regulations and reduce the age of their fleet, the airlines have two choices. They can either p;Iy the airframer for their latest version of an existing aircraft, with minor updates like extra fuselage plugs or engine upgrades, or buy a new aircraft. However, at some p(iint. because of new advances in technology like a more

*Teaching Assistant Student Member, AIAA

Copyright 0 1993 hy the American Institute of Aeronautics alld Astronautics. Inc. All ripht. reserved

Figure I - The SA-150 Top View

The SA-1.50 cruises at Mach 0.76 at ,an altitude of 40,000 feet. It can accommodate 10% 124 passengers in three cl:iss contiguratims. I n order to steal some of the mnrket share frtiin its ctimpetitiir, the design team made the SA-IS0 more economical to operate and more comforcrhle for ;ur travelers. Although the initial purchase price of the SA-IS0 ($37.7 million per unit) will he higher th:m the competitors, total operating cost will he lower as Icind factor and fuel prices increase. Through their studies, the We;isrl Works decided to optimize the de.si

Are:!.; of Adv:mcement

short Ii:iul trips, :is coinmuter m d feeder aircraft P .

To reduce operating costs, the SA-150 employs a V- tail design and a wing aspect ratio of 12 to reduce drag. Tbe V-tail was originally chosen to reduce surface area and skin friction drag. However, after further analysis, the once small wetted area of the V-nil was increased to satisfy one engine out control requirement. Although skin friction saving was not achieved, a second benefit of using the V-tail was a reduction in interference drag at the nil - empennage junction. After final analysis, the team concluded that a V-tail configuration did not reduce or increase induced drag when compared to a conventionill configuration. However, because the V-tail offer ii reduction in manufacturing cost and a distinctive profile, the configuration was retained.

Another major area of technological advancement lies in the wing. The use of a high aspect ratio wing helps to reduce induced drag, fuel burn and operating cost. The SA-lSO's aspect ratio of 12 is considerably higher than its closest competitor, the Boeing 737-500 (AR of 8). But the use of a higher aspect ratio wing demands special requirements.

With a higher aspect ratio wing, susceptibility to aeroelastic flutter becomes more of a concern than otherwise. The SA-lS0 design team opted to alleviate this possible problem by using an elliptical all composite wing box (Figures 2, 3). The traditional aluminum twin sp;u design was replaced by a one piece composite structure.

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I.cd~?.ddl

Figure 2-SA-150 Elliptical Wingbox Cross Section

FiguE 3- SA-2 Elliptical Wing hox

A trzide study compming cost and ease of manufacturing, structural weighr, and aeroelastic flutter was performed and an elliptical wing box design proved to be the optimal design. Although unusual, the elliptial design offers tlie second largest cross sectional area while containing minimal, stre concentration points. The elliptical shripe :ilsti perm it to be fil,ament wound, and automated to reduce cost.

Pronulsion Svstrm

The utilization of ii more efficient propulsion system reduces the airline's direct operating cost. In this technological area, the :urfrnme manufacturer have trnly limited influence on engine performance. This is usually left up to the engine manufacturer. The design team examined a number of current propulsion systems and chose the BMW-Royce Rolls BR-700-17 as the propulsion unit of choice.

This propulsion unit provided the required thrust of 16,000 Ibf. The weight penxlty was minimal, the fuel consumption very competitive at 0.62 Ib/lblhr. With a low wing design and minimal ground clearance for this type of aircraft, fwi diameter dimension hecomes an important factor in foreign object ingestion and maintenance services. The BR-700 fan dimnerer is S3 inches. The SA- IS0 is expected to meet the proposed Stage IV noise requirement.

The SA- 1 SO can :rccommodate three passenger configurations: I O X dual class, 118 single class, and a 124 high density class. To make the flight more comfortable for the air traveler. :UI obvious solution is to provide more piissenger room. The decision was made to enlarge the diameter of the aircraft. The cabin di'ameter stood at 12 feet 8 inches compared to I 1 feet and 7 inches for the Boeing 737-SOO. Even with the wider fuselage, the fuselage friction drag is kept low by designing the SA-150 with a fineness riitio o f X.12. Eight has been determined optun:d 3,

With ii seat pitch slightly larger them current stmdards, and elimination of the fold down tray behind the seatback will create :in even more spacious area. By having a wider body diameter. the extra comfort went into wider arm rests. Having tlie fold o u t tray in the arm rest mated a roomier feel :ind eliinin;ited the problem of fallen trays due to f:iulty restraining levers.

The SA-150 retlects the design team's philosophy of incorporating new designs and technology only in the areiis that can return improved and economical performance. The V-tail provided lower manufacturing cost, while the higher aspect ratio wing increased efficiency, iind the larger diameter cabin should he welcome to air travelers.

Conticuration - the AC-120

The AeroCoin design teiun of the AC-120 wanted to produce the most ;ieriidyiiainic;illy efficient small commerci:il aircraft without siicrificing p:u;senger comfort

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or minimizing direct operating cost 4. Like the other sin;dl commercial design team, the AeroCom team saw the role of the AC-120 as a commuter and feeder aircraft, s o ir too optimized the aircraft for a typical 500 nm city p i i r mission.

Their solution was to employ suitable amount of technology at crucial design criteria to m'ake the aircrnlt more economical to operate. Reducing induced drag :md noise level were two areas requiring new technology. Cost is always imprtant, so whenever possible, the AC- I 2 0 uses less expensive aluminum instead of composite materials.

Compared to current small commercial transpons. the AC-120 appeared very distinctive and unconvention;~l (Figure 4).

Figure 4- The AC- 120

The AC-120 employs a three lifting surface configuration with zero degree of sweep at the wing's quMer chord. Another distinctive feature is its app1ic;ition of a pai~ of swept-blades turboprop ell&' lines.

The aircraft's unique configuration was chosen to minimize drag build up, while retaining passe~~grr comfort, ease of manufacturiug and lower operating costs. With this configuration, the AC-120 can achieve :I cruise speed of Mach 0.68 at an altitude of29,ooO feet.

With a three surface design, drag is reduced hy using smaller control surfaces (skin friction drag) 'and frim drag. The small control surfaces were made possible hec;~use the AC-120 was designed to be neutrally stable during flight. Also since the control surfaces are placed i ~ t

extreme ends of the airmatt, the large moment m created required only minimal trim and control deflections. Although small, the cannrd control surface is flapped :I[ full span to produce the desired lift ctefticient.

Areas of Advancement

To make the wing more efficient. 'an aspect ratio of nine was chosen. This aspect ratio should produce improvements in induced drag while minimizing ;idw:rse aerodynamic effects like flutter.

A supercritical airfoil wa% used to provide greater tuel volume and extend the AC-120s range to 1550 n;iutic:il miles. It was also chosen for its high lift cciefficient ;ind drag divergence Mach numkr. To reduce cost without sacrificing performance, the wing uses single slot ted flaps. Winglets were also employed to further aid iii

induced drag rcduction ( ;~ l though the design was not oplunized).

Thc AC- 120 hw zero degree 0 1 sweep at the quarter chord. tlius ;11Iowiug for i i lower Mach number of 0.68. This ;iircraft : i p p ~ ; ~ e d outcl;issed at this Mach number

made diis compromise iii speed to improve fuel efficiency :uid cost. Since the primmy mission of this aircraft is to H y \hart hops, where the tn:ijority of the time is spent in cliinh :ind descesd segments. cruise performance at greater \peed wiis tiof delennined 111 he :I mqjor factor.

Pronulsion Svstrin

when coinpared to current turbofan trwsports. The team L/

While current design of the swept hlade turboprop engines exist, none ilre capable of producing the horsepower required (8,000 HP) to power for the AC- 120's. The design team, however. pro,jected a future growth derivative of the <;MA 2100 Turboprop to he a viable c;indid:ite. Such growth version would require a fan diameter of 54 inches and operate at a fuel c~)nsuinption of 0.41 Iblhplhr.

The turhoprop engines were choseo for their favorable ch;mcteristics. These include lower emissions over turhofiiiis, reduced ground handling expense and reduced miiiiitc~~iince ;ind ;squisitii)n cost. The design team coirteiids that swept hlade technology allows a 30% improvemelit in fuel s;lvings over turhofms.

P:issrneer Cointort

The AC- 120's passenger cabin is designed IO maximize p:lssenger comfort in ;I n:urow body aircraft. The iiirerior diuneter (1 1.6 t t ) of the cabin is kept to a

level ol comfort as current aircrxft. minimum (for drag reduction) while providing the sNne W

The interior I;iyout comes in two class configurations. The mixed cliiss seats 110 passengers (business and tourisi). while the all tourist class seats 120 passengers. Seat pilch range from 36 iilches (husinw class) to 31 inches (tourist cl;iss). The 31 inch seat pitch is coinp;uahle to the Boeing 777 economy seats.

Summiry

Thc AC-120 uses suitahle iunount of new technology to m;ike the aircrzlft more efficient and priced competi~ively while keeping oper:ition and maintenance cost d~iwii . And the bottom liiir is that the AC-120's :squisition cos1 is 1524.5 million. At this price, the huyer gets ;III ;iircraft with advanced wing design. exotic styling. with ii more efficient configuration and propulsion system The iiircraft price is kept low by using inexpensive : i luminum construction with minimal ~~ppIic:ition of more expensive composite materials.

Thc 250 - 150 P;~sse~izer Airccdt Desizn Proiects

.lustitic:itioii

Any xircraft entering Ihis segment of the market had hetter come fully equipped 11) challenge the established fleet\. The current lleet includes tierce competitors like

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expected to uavel the Transpacific region. This msIaic\ into an average growth rate of 8% annUdly between 1090 and 2001. In addition. 24 million passengers me e x p i ~ d IO mvel h e between Empe and Atlalpacific.'

These significant increases in passenger travel h;i\fe recently sparked inlerest in the development of a very large transpon aircraft. As one analyst put it. "...The growth in long-haul mffic poinu 10 a need for very long nnge aircraft chat rn bypass the Tokyo botcleneck ;md fly fmm 8 ~ - ~ srat. mi unrefue~ed ..." 8. This need IS

being given serious attention: Boeing and the Europein parmers of Airbus announced last January that they were joining to conduct a feasibility study on the posbihle development of an aircraft that would fit this niche 9

In keeping with t h a e developments. one design grtiup at Cal Poly was provided with a request for propowl (RFP) to design such an nircraft. The requirementh specified the n d for an aircnft capable of carrying d(X) passengers a distance of 7.000 nm. with an addition;il 30,000 Ibs of cargo. A growth version, capable o t unying IO00 psengen: a reduced & a c e of 5.500 nm. was also required. The aircmft was to enter service hy Ule year 2005.

the VLCT- 12

The group discovered slime serious difficulties whuii developing an aircraft of this size. Airpon cornpatihilit) wm chief .among these. The sheer physical size ( 1 1 the aircraft led to questions of gale compatihility. ndequ:ite maintenance facilities. and runway strength\. Slructdly. the aircraft needed to be sound. lightweight. and economically feasible. An engine capable of Inrge amounts of thrust was required IO keep number of engines Io a minimum. And finally. the aircraft need t i i he comnetitive economicallv. These dwllenees were met Ulhr bestihey could by the Aeroheaas design-team with their aircnft the VLCT-13.

At a takeoff weight of 1.4 million pounds, the VLCT- 13 weighs almost twice as much as the Boeing 747. The aircraft was sized assuming an L/D of 25 and a specific fuel consumption (Ib/lb/hr) of 0.49. While these values may seem optimistic, they nonetheless were required in order to bring the rakeoff weight down to a somewhat reasonable value. The direct operating cost of this aircrafi was determined to be 2.36 per passenger seat mile.

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Win. n m

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The VLCT- 13 spends approximately R-13 hours cruising at Mach 0.83. A high performance wing, therefore. was crucial to mnking the aircraft a success. The X,(X)0 ft2 wing has an aspect ratio of 11.6, daignrd to significmtly reduce the induced drag. This high mpect ratio. combined with a sweepbnck of 35' to minimize compressihility effects. necessitated a structural root chord of SO i t i l l a thickness [if 6 feet. A supercritical airfoil w:is ch~isen for this :iircmft, n 12% thick CAST 10- 2.

I n order for :uqxins to ;icccinuniKL?te this huge a i r d t . che VLCT-13 includes the ciption rif a folding wing-tip. sunil;u to the Btring 777.

Pronulsioii Svstrins

The vLcT-13 '~ huge takeoff weight required 400,000 Ihs of thrust for wkeiiff. For a four-engined aircraft. this trnnslated into the need to have an engine in the 100,000 Ih thrust cntegory. Engines of this size are currently being devebiped h Rolls-Royce, Pntt 1G Whiney, and Genenl E la r i c l ! . f2 ,

Beciiuse of the low specific fuel consumption required, W engine bleeding had t o be kept to a minimum. The VLCT-13 uses vnrlex turhines located on the winglips in order to help aenerate power for the .airplane's electrical,

these rimes.

Figure 6- The VLCT-13 Figurr 7- VLCT-13 Vonex turhines

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The goal of the design team was to accommodate the structural requirements imposed by aerodynamic .and inertial loads at the lowest possible cost and weight penalty. At Mach 0.83, thermal considerations were not design drivers. To achieve this, the VLCT-13 uses Aluminum-Lithium for 80% of its exterior material. Al- Li has high strength, superior fatigue resistance, and a relatively low cost 14 Compared to conventional aluminum alloys (2024-f3 and other series) AI-Li is 10% lighter and stiffer. Table 1 shows the advantages and disadvantages of this material.

Table 1- Advantages and Disadvantages of AI-Li

Advantages * Existing machinery & equipment to work material

- Worker; require no special ~ i n i n g . reducing production CQSU

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of payload, and return, without refueling. The technology date of this aircraft wm to be 2010, with an operational capability date of 2015. Each desibm group took a unique and challenging approach to the prohlem.

ConfiL.uration - the O s m

Weight. aerodyn'mic efficiency. loadahility, and cnst were the chief design drivers for the Ostrich (Figure 8) 16. Its three fuselages support a huge, 420' wing, mnking airstrip ccnnpatrhility a mqjor concern. Wing!% help reduce Uie wingspan ;ind aid iii the reduction ot induced drag.

Dbadvantages * Tiwee times higher wst Wan aluminum. hut lower rhnn titanium or campsites

*Superiorfatigucrcsistance

- Grenter corrosion resistulw

* IO% greater tensile sixength over common aluminum

* Lighter weight dloys

* Higher producliiin tolerances required

* Safety precautions in cisling

a i d ! . This & r a f t must be cipabfi of carrying R00,(11H) pounds of payload a distance nf 6,SOO nm. off h ~ d XS'% 'vi

Figure X- The Ostrich

The Ostrich sports two T-tails. mounted on the outer two fuselages. 11's six engines. generating more than IOO,O(N) Ihs of Uirust each. are mnunled along the wing. outho:ud trf the outer fuselages. The wing has an mr0dyn:unic :ispect ratio (if 13, but a suuctunl aspect ntio c i l only 10 due tu the outer fuselages. The airfoil used was ii derivative (if the superwiticiil MS-86. Active I.unin;u Ilow cniitr(~I is used. The total cost of the Ostrich is S1.2 hillioii d(11I:us.

,4n:a of Atlv:iiiceincn!

mtihmlv de^

A rnultihrrdy xirmitt (iffers mmy of the :idvanLiges of ii sp:in-disuihuted ;iircr:ilt while retaining contiguntional :ind oper:iti~in;il c1i:ir:tcteristics like those of a convention:il design. B y distrihuting the lond along the wing, ii reduction i n wing root hending moment is :ecriinplished. This iri turn lightens the required suucture. ;ad reduccs Uie (iverdl wing weight.

Chst was kept to :I minimum hy electing to use existing fusel;iges for !he ouler two. McDoimell D~ugl:~% C-17 fusel;lges were used lor llle outho:ud fuselageS. :I separate center fusel:ige was designed. Further reduction in cost is oht:tined through part common:tlity ; i ~ ~ ~ c i a t e d with the use o f multiple fuselages and empennages.

Altliough i t two-hody aircraft offers the same ndv;tnt:iges 21s :I three-body, this concept was rejected. A signiticmt reduction in ride qu:dity during mimeuvers exists hecause the Uocips :md crew are not situ:tted along the centerline of the aircraft. In addition, existing

fuselages could not be used hecause of insufticient cargo capabilities.

m n a r Flo w Control

In order to achieve the necessary L/D ratio of 24 for this aircraft. the Ostrich incorpclrates the use of a n active laminar flow control system (LFC) on the leading edge and top of the wing. LFC works to increase the L/D hy sucking the shear layer through a porous titanium skin. increasing lift, and reducing the skin friction drag hy delaying transition. The LFC runs full span, and up to 70% of the wing chord.

Studies show that by the year 2010, the technolq!y date of the Ostrich, a 20% increase in L/D can he achieved through the use of LFC l7 . This in turn results in less mission fuel, lowering the takeoff weight. The added LFC system weight is more than offset hy this reduction in fuel.

The LFC consists of a titanium skin placed on the leading edge and top surface of the wing. Titanium w a chosen for its hardness ;md low coefficient of thermil expansion, ensuring the integrity of the very small holcs used in the system. The holes are machined such that the diameter of the holes decrease as they approach the surface, reducing clogging. A glycol solution is hlowo outwards from the holes prior to takeoff to clear the holes and to prevent insects from sticking.

Cornnosite S t r u a r

The final advance in suhsonic technology used iii the design of the Ostrich is in its exlensive use of comp(isites. Figure 9 shows the materials breakdown for the Ostrich. Weight issues become extremely important for this aircraft, sized at a takeoff weight of 2.3 million p(iunds. The extensive use of composites was necessary io generate even this extremely high value.

Gnphh9epory

Tmnim sun. Graphne Structure

Figure 9-The Ostrich 's Materials hreakdowrl

The composite used was graphite/epoxy. Although it provides high strength and low weight, it is hritUe :itid does not yield before failure. The entire structure is 56% composite, allowing an overall 30% reduction in empty weight '* Although today's aircraft typically use no more than 20% composites in their structure, trends suggest t11;it hy the year 2010, most aircnft structures will he prim;uily composites 19,

Cost of these composites is dehatahle. While genenlly composites are more expensive to manufacture and m:unt;un. there may actually he ii reduction in overall cost due tu weight s:ivings and reductions in operating and liti-cycle costs 18.

I

< I I 1 - , W

Figure I O shows the three view of the Cet:iceopteryx2". 11's most ~iutst:inditig fcatures include the .i(iitied wing :ind the caiiwd. I t has ii conventional. ;dthough huge, fuselage, and ii conventiomal empennage. It's six engines each generate about IW,OW Ihs of- thrust and the Cet;iceopteryx weighs in zit 2.14 million pounds.

Figure 10- The Cet;lceopteryx

Joined W b

The chief iidvantages of the joined wing are threefold. First, the wing cain he constructed 6.591 to 7R9, lighter than ;in :ierod n:unically equivalent cantilever wing-tail cont'igur:uion 31. 22. 27. For the joined wing, the bending axis of' [he front and rear wing comhination is a plnne through the neutriil axes of the front and rear wings (Figure 11) . The lift may he decomposed into two components- one par;illel to the bending axis and one perpendicuku to it. The wing's truss structure effectively dissipates the inpliine load component, and the out-of- pliine component is dealt with hy the appropriate distrihution of m:iterial in the wing's hox structure (Figure 12).

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Figure 11 -Bending Axis, .Joined Wing

Figure 12- Wing Box. Joined Wing V'

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Secondly, a higher aspect ratio can he achieved. coupled with an increase in aerodynamic efficiency. The higher aspect ratio is achieved through the structural bracing of the fore wing by the aft wing. In addition, due to the increased surface area (two wings instead of one, but one wingspan) the Oswald’s efficiency factor increases, and can have a value greater than one. The inherent superiority of the rear forward swept wing is preserved by its wingtip bracing to the front wing; its suuctural divergence is thwarted.

The third chief advantage to having a joined wing is its increased fuel capacity (Figure 13). This is due to the increased wing box structural area caused by relocating the fore and aft wing spars outward, a. discussed above. Also, the additional span from having two wings increases the fuel capacity when compared to a conventional aircraft of equal span, planform area, and airfoil thickness.

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Figure 13-Fuel Volwne Compnrison . .

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The mission specified for the global range military transports requires both extremely large payloads and range. This in turn necessitates a very large, heavy aircraft. These requirements induce unique design challenges. Two creative solutions were provided by design teams at Cal Poly: the Ostrich :ind the Cetaceopteryx.

The Ostrich consists of a three fuselage design to accommodate its huge payload requirements and to distribute the load across the wing. Other technology advancement5 used in its design include the use of a laminar flow control system to help increase the LID, and extensive use of composites to help keep the aircraft weight as low a5 possible.

The Cetaceopteryx has ajoined wing on ill1 otherwise conventional aircraft. This wing ha.. a lighter structure than a comparable conventional aircraft, has increased aerodynamic efficiency, and has the ability to c q more fuel. These traits become very important when considering the unique and difficult mission this aircraft is asked to perform.

References

1. Aviation Week Group, “World Aviation Dictionzy”, M&w Hill, Inc. New York, New York

hd

2. Alkema, Kevin, et al,“Weasel Works SA-150 Design Study of ii 1IH) to lS0 Passenger Transport Aircraft”, Aeronautical Engineering Dept., Cal Poly State IJniversity, San Luis Ohispo, CA May 1993

3. Roskun, I:m, s.c~ Roskxn Aviation and Engineering Co$oration, 1085.

Dur;m, D et al. “The AC-120 Advanced Commercial Trmsport”, Aeronautical Engineering Dept., Cal Poly State Ilniversity, S:UI Luis Obispo, CA May 1993

S. Moskalik, S. et al, “JB-300 An Advanced Medium Size Transport for 2005”. Aeronautical Engineering Dept., C;iI Poly State University. Sail Luis Obispo, CA May I093

Pratt & Whintey, “Information Package on STS90A Turhofxi fix 2015 Entry to Service”, 1W3

7. Oft, James. “Competition to force new airline structures”, Aviution Week rind Spucr Technology, Much IS, 1993

Kandeho, St;mley W., “Stahle Engine Sales seen in late 1994“. Aviution Week rind ,Spuco T(xhno1og.v. Mnrch IS. 1003

‘1. Butterworth-Hayes. Philip, “Europeans to he ma.@ partners in XOO-seater development”, Aerospiicr Anierico, April IO93

10. Be:il, Pameki et A, “VLCT-13, A Transport for the 21st Century”, Aeronautic;il Engineering Dept., Cal Poly State University, Sail Luis Ohispo, CA May 1903

4.

6.

8.

11. Rolls Royce Pamphlet, I903

12. “105,400 Ih Thrust Reached in GE9O Test”, Aviutim Week rind Spticr fi!c/mobgy, April 12, 1993

13. Patterson, James C., and Flechner, Stuart G., Exploratory Wind-Tunnel Investigation of a Wingtip- Mi)unted Vortex Turbine for Vortex Energy Recovery”, NASA-TP-2468. Langley Research Center, Hampton, VA 19X.5

14. Niu, Mi, Airframe Structural Design, Commilit RKSS Ltd, CA April 19x9

IS. AIAAICieneral Dynamics Coipration. Unilnrlergruduure Tuiiii Aircrurfr Df,.si,vn Coniixrifion (RFP), AIAA Student Programs, W:ishingttni, DC, 1992

16. Aguizu, ldin et :iI, “A Global Range Military Transport, The Ostrich”, Aeronziutical Engineering Dept., Cal Poly State I.Jniversity, San Luis Obispo, CA May 1903

Control for Transnort Ai rmf t , American Institute of Aeroileutics and Astrmxmtics, New York, New York, 19x3

17. Lang, R.H., -tion I )f L;uninar Flr )W

I X . L;rng, R.H. and Moore, I.W., Application of Composite Materi:ils :ind New Design Concepts for

X

Future Transport Aircraft, International Council 1 1 t Aeronautical Sciences Proceedings, American Institute of Aeronautics and Astronautics. New York. NY, 1982.

19. Niu, Michael C.Y., 7 c , Conmilit Press Ltd., Hong Kong. 1992

20. Brivkalns, Cahd et al, “The Cetaceopteryx, A Glohal Range Transport Aircraft”, Aeronautical Engineering Dept., Cal Poly State University, San Luis Ohispo, CA May 1993

21. Cliff, S.E., moo, I. M., and Smith, S. C., The Design of u Joined Wing Flight Demonstrutor Aircrufr, AIAAIAHSIASEE Aircraft design, Systems and Operations Meeting, AIAA 87-2930, St. Louis, Missouri, 1987

AIAA 23rd Aerospace Sciences Meeting, AIAA 85- 0274, Reno, NV, 1985

23. Hajela, P., Weight Evuluution qf Joined Win,p Configuration, NASA Contractor Report 1665‘12. 1984

22. Wolkovitch. J., The Joined Wing: An Ovcrvien.

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