The Edge supersonic transport

Table 12.5 Appendix Locations for The Edge Supersonic Cruise Data Q., Cm CD0 L/D Appendix p.7,8 p. ll p.15 p.19 (BA-BG) Datcom 4.1.1.2-A 4.1.4.2-C 4.1.5.1-C N/A 4.1.3.2-C 4.1.3.3-C 12.2 Summary of Performance Characteristics As shown in Figure 12.4, the immediate advantage of a variable sweep aircraft is evident. The superior subsonic and supersonic cruise L/D values are a direct result of flying a two configuration aircraft. Table 12.6 summarizes these performance values, and drag polars for all flight regimes are presented in Figure 12.5. With these performance characteristics, The Edge aircraft aLlows for efficient subsonic travel; therefore, The Edge has an improved ability to provide economical service subsonically overland.

= Takeoff 2O ¢ Subsonic Cruise a Supersonic Cruise 0 ! ! l 0.0 0.5 1.0 1.5 Lift Coefficient Figure 12.4 Comparison of Lift-To-Drag vs CL Values for The Edge Table 12.6 The Edge Performance Characteristics Summary L/D Mach # I C_uiro d AOA (deg) _c Configuration Takeoff 0.24 0.84 11.6" 0.73 7.6 TE flaps, LE slats & elevators @ full deflection Subsonic 0.7 0.68 !5.0" ' 0.73 11.0 Clean, unswept Cruise Supersonic 2.4 0.14 2_0" 0.52 9.6 clean swept Cruise Emergency 0.27 0.72 14.6" 0.56 2.4 TE flaps (outboard only) LE Landing slats, swept .57 2.0 " Takeoff 1.s * Subsonic Cruise • Supersonic Cruise 1.0 '_ 0.5 0.0 r- i 0.0 0.1 0.2 0.3 0.4 Drag Coefficient Figure 12.5 The Edge Drag Polar Comparison 12.3 Emergency Landing Conditions The Edge aircraft is at a most critical stage during takeoff. Namely, it is generating its greatest amount of lift. Once airborne, the aircraft must provide for systems failures and the need for immediate landing. Subsequently, The Edge has been designed with enough control power to accommodate such an event, as discussed in Stability and Control (Section 13.0).

Since The Edge is a variable sweep aircraft, the possibility of failure of its wing- sweeping mechanism is introduced as an additional safety concern. The Edge wing was initially designed to have enough surface area while swept back to provide adequate lift for landing in such a configuration should the need arise. This d_sign point has been met, and the aircraft can indeed land fully swept at 15" AOA and 180 kts 29. However, other issues need to be addressed in further analysis of this flight condition, such as possible tip stall due to an excessive AOA, which would severely limit or destroy longitudinal control power.

t Table 12.7 Appendix Locations for The Edge Emergency Landing Condition Data CI. CDo High Lift p. 3,4 (U-Z) p. 12 (DD-DI) p. 16,17 Appendix 4.1.1.2-A 4.1.5.1-A 6.1.1.1-A Datcom 4.1.3.2-A 6.1.1.1-C 4.1.3.3-A 6.1.4.2-1 12.4 Balanced Field Length In order for The Edge to be compatible with existing airports, the aircraft must have a total takeoff distance of less than 12,000 feet, including the distance required to clear a 35 foot obstacle with one engine inoperative. As can be seen from Figure 12.6, when the aircraft has accelerated to a distance of 4,422 feet, it begins to rotate; the time to rotate to a liftoff attitude is largely dependent upon the pilot, but is typically 3 seconds.

After this rotation point, however, the pilot is Committed to takeoff. Figure 12.6 also illustrates a ground run of approximately 5,232 feel From these considerations, the balanced field length is calculated to be 9,202 feet.

v V Decision Point --- 5185 ft Ground roll "- 5232 ft.

BFL 9202 ft _- Figure 12.6 The Edge Balanced Field Length

13.0 STABILITY AND CONTROL

13.0 Stability and control 13.1 Longitudinal Stability As can be seen from the table below, The Edge is longitudinally stable except in the supersonic cruise regime, where it has been designed to fly with approximately 4.5% instability.

The jump from a significantly stable configuration in the subsonic regime to a slightly unstable one in supersonic flight is a direct result of The Edge swing-tip design.

During acceleration throughout low speed and subsonic cruising flight, the aerodynamic center (AC) is being influenced aft by the loading of the wing tips; at the same time, the AC is being drawn forward by the lift generated on the main wing. The result is a virtual negation of any AC shift while accelerating to subsonic cruise at M = 0.7, resulting in a subsonic cruise AC located approximately 73% aft along the main wing root chord. This AC position may seem odd when compared to a typical delta wing subsonic AC location of approximately 25%; however, it should be clear that the high wing tip loading of The Edge is what drives the AC back to this aft position.

Table 13.1 The Edge Longitudinal Stability: Static Margin Subsonic Takeoff Supersonic Cruise Cruise Resime 2.4 0.24 0.7 Mach Number 11.6 4.6 2.0 AOA (deg) X'cg (% Cr) 0.54 0.54 0.56 X'ac (% Cr) 0.73 0.73 0.52 -0.19 -0.19 0.05 Static Margin (%Cr)

While passing through the transonic regime, The Edge wing tips sweep

incrementally aft. Upon the achievement of full supersonic cruising flight, the tips are fully swept, producing an arrow wing planform and a forward AC shift to about 52% aft along the root chord. It is clear that as the wing tips are swept back, the main wing is left to generate the vast majority of the lift required for cruise; and as expected for a planform such as that of The Edge, the supersonic AC position resides at about the 50% root chord position 29.

The Edge has been preliminarily designed with a center of gravity (CG) location as close as possible to the supersonic cruise aerodynamic center. The potential of this philosophy is that marginal positive stability or neutral stability favors extremely small control deflections resulting in lower induced drag. Although this was difficult to achieve for The Edge, as is evidenced by its 4.5% instability in supersonic cruise, further design work may indeed push this static margin to a marginally stable value.

Figure 13.1 below illicits the full CG envelope of The Edge. This envelope is notably small, allowing the aircraft to operate anywhere in this CG range with only minor affects on stability. As Shown, the range of CG shift is 54% to 56% of the wing root chord.

850000 P=x + Fuel _ I

_- 850000

=i It + Fuel o=o r- _?

o 3= 450000 Fuel _l_ <--- 59' -_ 250000 2000 2100 X cg (in.)

Figure ]3.1 The Edge Full Mission CG Excursion Diagram 13.2 Longitudinal Controls and Controllability A key point in The Edge design philosophy is to take the best ideas offered by previous supersonic transport designs, as well as any other maverick ideas of special potential, and evaluate their net worth in achieving the overall design goal of economic feasibility. One decision arising from this evaluation is the elimination of a horizontal taft. The subsequent benefits of reduced aircraft empty weight have been discussed previously in this report; the topic here is the longitudinal control challenge inherent in a tailless design.

In sizing The Edge elevon surfaces, the X-plot method 10 was attempted and furnished values of elevon area approaching the size of The Edges main wing (this attempt can be found in the Empennage design section of the Appendix). Preliminary design of these surfaces was therefore accomplished by an analysis of previous tailless transport configurations such as the Concorde and the TU-144. This initial analysis placed the existing elevons to within 10% of their final size, which was determined using longitudinal control analyses 32. The high aspect ratio wing tips allowed The Edge to use elevons which are markedly smaller as a percentage of overall wing area than those of the Concorde design 21.

Table 13.2 summarizes pertinent information for the flight conditions at which stability and control derivatives were calculated. Table 13.3 is a summary of these derivatives in the three flight regimes of greatest interest: takeoff, subsonic cruise and supersonic cruise. These values were calculated using the methods established in references 29 and 32. However, it is difficult to evaluate their import fully without comparison to other aircraft of similar size and configuration. And since such information is closely held by the private sector, the best information available has been the subsonic data relating to the Boeing 747-SP 23. Even in the subsonic regime, though, the limitations of using this data are evident since the 747 configuration is substantially different than that of The Edge 23.

With this in mind, initial concerns were focused toward the relatively small values obtained for elevator control power, namely Cm&= -0.25 at takeoff speed as compared to -1.4 for the 747 on final approach 23. However, Figures 13.2a, b,c verify that sufficient control power is in fact available to handle any normal configuration variations within takeoff, subsonic, and supersonic flight, as well as to maneuver the aircraft between these regimes. On each of these figures, the Cm = 0 line occurs at a reference CG of 0.58; The Edge design trim point locations are also shown. Cockpit control forces will be within standard limits 24 by means of an artificial control force feel system 10.

Table 13.2 The Edge Flight Condition Summary for Stability and Control Analysis I Flight Subeonle Supereonio Condition Takeoff 35.000 gO.O00 Altitude (ft) See Lev_ C4mtlr of 0.$02 0.$40 O. $42 Gravity (X'c|) 0.7 2.4 Mobil Numb4r 0.24 Ilonln|l 4.g 2 11.6 Attitude (deg) Ixx (_mlem_ 2.40 x 101o _lkl x 10 _ 2.64 x 10 w ly,/ (,,q_ma) 7.71 xl00 7.71 x 10 I e.04 x 10 e Ill (olug e_t't ) 4.09 x 10 • 4.09 • 10 m 3.87 x 10* Iu (-,q/#) 3.00 x 10* 3.03 X 100 2,81 x 10e Table 13.3 The Edge Stability and Control Derivative Summary Takeoff Subsonic Supersonic Stability Derivatives Cruise Regime Cruise -0.34 0.11 -0.34 Cll a -26.1 -26.6 -17.4 Cug -0.21 0.02 0.21 CLy 2.64 1.66 2.64 cL,, 1.35 0.83 0.12 CLq 0.01 0.04 0.14 Co u 4.25 0.51 0.44 CL_ 0.04 0.04 0.03 COlE -I .49 -0.25 -0.41 CMa_ -0.447 -0.014 -0.023 Cop -0.246 -0.24 -0,241 CIp 0.02 0.023 0.029 CILIA 0 0.009 0.003 Clsfl 0.408 -0.021 0.232 c.p 0.12 0.273 0.081 c.p 0 -0.0018 -0.0024 Cnl A -0.156 -0.367 -0.1 39 CnSR -0.07 -0.11 -0.02 0 -0. 006 -0.018 0.06 0.17 Cy r 0 0 CylIk 0.077 0.047 0.053 CYSR

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_J The Edge will utilize a futuristic fly-by-light flight avionics package. As mentioned in Section 14.0 of this report, the several benefits offered by such a system include those of weight savings, maintainability, and insusceptibility to electromagnetic interference. Fiber optics will be employed to transfer pilot inputs to the appropriate hydraulic or electronic flight control actuators 23.

For the supersonic cruise condition wherein a longitudinal stability augmentation system (SAS) will be employed, the angle of attack feedback gain for the elevon control loop is determined to be Kct = 0.003 deg/deg. This gain is achievable with current technology 10.

13.3 Lateral Stability.

During low speed flight, and during takeoff in particular, unstable weathercock characteristics are present, as can be seen through Cn_! in Table 13.2. Lateral instability, however, while a concern, is not as inherently problematic for The Edge as is longitudinal stability; with the exception of structural weight, there are no pressing limits on lateral control surface sizes as there are in the longitudinal case. The vertical tail and rudder control of The Edge are designed such that substantial lateral control authority is provided in all flight regimes.

13.4 Lateral Controls and Controllability Lateral instability at takeoff is therefore addressed by using this control authority managed by a lateral SAS with a sideslip to rudder feedback gain of KI]= 0.016. It is probable here that the rate of sideslip will also be fed back to the rudder 10. As discus_d in Longitudinal Controls and Controllability, a futuristic fly-by-light flight control system will be employed aboard The Edge.

FAR 25.147 states that an aircraft must be able to effect reasonable sudden changes in heading with the wings approximately level. In order to meet this requirement, sideslip angle (13), aileron deflection (_a), and rudder deflection (8 r) for the control surfaces.must be within acceptable limits for the worst case scenario; this situation is that wherein the right outboard engine is inoperative during takeoff. Rolling moment, yawing moment and sideforce due to thrust exhibit their greatest values in this case. Table 13.4 illustrates that 13, _ia, _- and are will within the typically acceptable limits; therefore, the requirements of FAR 25.147 are satisfied.

Table 13.4 The Edge Lateral Controllability Summary FAR 25.147 Takeoff Subsonic Supersonic Requirements e < 12 -9.37 -I 1.36 -0.48 e w <25 0 17.49 -0.324 e 0.905" <25 10,3 -0.528 8r 13.5 Handling Qualifies Without a flight control system, an aircraft such as The Edge should exhibit vastly different handling qualifies in one regime than in another. This is true for The Edge. As can be seen in Table 13.5, the approximations for longitudinal and lateral control do not generate numbers in unstable regimes. The Edge aircraft is longitudinally unstable in supersonic cruise, and laterally unstable during takeoff. This can be corrected with the implementation of a flight control system with the appropriate control laws. In the remaining flight regimes, The Edge aircraft falls into either level 1 or 2 flying qualities for both longitudinal and lateral approximations 3].

Table 13.5 The Edge Handling Qualities Takeoff / (Level) Subsonic / (Level)

Supersonic / (Level)

Short Period

0.5 0.2 N/A 03sp (rad/s) 0.96 / (1) 0.61 / (1) N/A _sp (rad/s)

Phugoid

0.05 0.05 0.04 fop (rad/s) T 0.018 / (2) 0.02 / (2) 0.19 / (2) _O (rad/s)

Dutch Roll

NIA 0.78 / ( 1 ) 0.77 / ( 1 ) 03]3 (rad/s) N/A 0.08 / (1) 0.05 / (2) _p (rad/s)

It should be noted that thesenumbers representapproximations,and the actual

aircraft transfer functionscould exhibit other problemsand/or benefitsin the three flight

regimes. These approximations do, however, indicate the immediate benefits of the

variable sweepdesign: the achievementof superior subsoniccruise performance,a fact

moreeasily seenwhen consideringthe L/D ratio of 11 for this regime.

13.6 Proposed Flight Control System Using The Edge geometric data, flight conditions, and the stability derivatives shown in Table 13.3, a preliminary step was performed in the design of a longitudinal flight control system for The Edge aircraft in subsonic and supersonic cruise. Using small perturbation theory, aircraft transfer functions were calculated for relating the forward velocity, angle of attack, pitch angle, and pitch angle rate to elevon deflection. The corresponding root locus for pitch angle to elevon deflection was obtained, and a time response to an open loop unit step input for both cruise conditions was produced. These charts are presented in Figures 13.3-13.6 for the two cruise conditions.

I .3 / ICe m l Da-hetl 1 lae= t.elpre_wt a .24 -- lm lc m ilral ton dim= l nellal:iue fenetm_ lain • 18 3g -._) -- -,10 -.Z4 -- \ \ --.3 J ' I I I I l I l | t t i I i I - .31 - .22 -. 13 - .84 Figure 13.3 The Edge Subsonic Cruise Root Locus for Pitch Angle Transfer Function ICC u .0 t _ .

.3 LOop R_ ! UnL'& $'_ Input i luO 0 30 50 90 Tim_ Figure 13.4 The Edge Subsonic Cruise Time Response for Pitch Angle to Eievon Deflection I .Z II g poLe mIGn_htion due I:o _ I • 1"_1 ,iP • 0_67 mIgativc fm'tm_ gain 1,111 I il -. l16G?

-. l'n -.2 - .48B - .317_ - .2b5 -. 153 - .0417 .B7 ]ll_l s Figure 13.5 The Edge Supersonic Cruise Root Locus for Pitch Angle Transfer Function 0 1.0 ICe 1: P u 1.5 4: 1.Z .9 C leme<l Loop ]H_l_ Uwll_ :3t.cp Inlml; .6 .3 8 i i , , i l , I i I i i i i I i i l t I | i i i O 28 48 68 88 1BO Tim: Figure 13.6 The Edge Supersonic Cruise Time Response for Pitch Angle to Eievon Deflection From the subsonic cruise root locus shown in Figure 13.3, it is evident that the aircraft is stable providing there is no loop closure. With the addition of lag and/or lead compensators, the migration of the closed loop poles can be altered so as to provide a stable closed loop response. It is clear that the short period damping needs to be increased to reduce transient oscillations.

During supersonic cruise, The Edge is an unstable aircraft. This is evident from the root locus Of Figure 13.5, as there is an unstable pole, thus resulting in inherent instability. First, a negative forward gain would provide stable closed loop pole migration. Second, the addition of a lag and/or lead compensator, would provide

adequate phugoiddamping.By adjustingthe forward andfeedbackgains,the propertime

• response canbe achieved.

By utilizing feedbackto obtain the resulting g-forces,the constraintson the gains

will be evident. Further design would include a Bode plot analysis, and observing the

compensator effects on gain and phase margins, crossover frequencies and crossover magnitude curve slopes.

It must be clear.that this is the fast cut design of a flight control system for The Edge aircraft. Upon its completion, a sophisticated flight control system assembly will be required to monitor the a.c. location and its shifts from stable to unstable modes of flight.

Further analysis is required for power approach conditions for both unswept and swept configurations. Additions to the flight control system to compensate for these modes of flight will be necessary, with special consideration being given to the emergency landing (fully swept) condition, wherein a loss of control power at high angles of attack could produce a critical situation.

C-2-

14.0 SYSTEM LAYOUT

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14.0 System Layout

The overall aircraft systems placement is shown below in Figure 14.1.

1NT_bLF'I.IEL S'I'CI_G[ typ ---_, _ _-_ AVIONICS _ACIS Figure 14.1 The Edge Systems Layout 14.1 Fuel System The preliminary design of The Edge fuel system is such that the highest degree of versatility, dependability and maintainability will be achieved.

As shown below in Figure 14.2, The Edge utilizes two main integral fuel tanks for the storage of JP-4 fuel, one located in the midsection of both wings. These two main tanks make use of the lateral wing rib design of the wing by allowing them to act as longitudinal, unidirectional fuel baffles; two additional bi-directional baffles are located laterally. This design inhibits sudden fuel transfers, while using wing incidence and gravity to feed fuel to the two fuel pump locations aft and inboard in each wing. For in- flight engine starting, fuel may also be pumped using auxiliary DC pumps driven by the auxiliary power unit (APU), which can be operated in flight as well as on the ground 2].

/-_ FIRE WALL

/ _ FUEL PUMPS

SCAVENGER PUMPS

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FILL PORT

OVER lING _

TIO IAY \ FLO! BAFFLE typ

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\, \ \, The Edge Fuel Tank Configuration Both main tanks have identical capacities and, by means of the fuel tank cross flow tubes running bidirectionaUy along the carry through spar shown in Figure 14.2, both tanks can be used to feed any engine; likewise, each engine has an emergency fuel shut-off valve and backup valve. An electronic fuel imbalance monitoring system will regulate left/right tank pumping to maintain aircraft lateral balance.

The fuel tank cross flow tubes also provide a single point fueling capability

(simultaneous fueling of all tanks),with anoverwing fuel port locatedat the leadingedge

of both wings.

As Figure 14.2 suggests,the rear fuel tank f'trewalls are placed substantially

forward of the landing gear hardpoints, keepingthe tanks out of dangershould a tire or

gearfailure occurwith the gearextendedof retracted 21.

14.2 Hydraulic and Electrical Systems

The Edge hydraulic controls package will be designed around four separate 4000 psi systems, one driven from each engine, and each with the capability to assume vital flight control functions; all flight controls will therefore be thrice redundant. In addition, a Ram Air Turbine (RAT) will be provided with automatic and manual deployment systems in case of full engine failure in flight. The RAT will be capable of providing power to both the flight control computer and the hydraulic controls actuation system during flight at subsonic speeds.

Each independent hydraulic system will be operable on the ground by means of its own electric pump, and will be placed in the aircraft with serviceability as a primary consideration.

The Edge electrical system will feature fully isolated primary and standby systems, offering a thrice redundant electrical system arrangement. The flight control computer will be designed to operate if necessary from an additional electric backup motor driven by the RAT.

It must be noted that these systems are subject to increases in technology. For instance, by the time of The Edge construction, fly-by-light systems may well be at the forefront of technology; this would allow the use of small, DC hydrostatic pumps local to the actuators they are powering. These compact systems would be directed by a fiber- optics network interpreting pilot control inputs. Such a system would be advantageous not only due to its dramatic weight decrease and superior maintainability, but also because of its immunity to electromagnetic interference 23.

14.3 Environmental Control Systems Since The Edge cruises supersonically at altitudes well into the stratosphere, a safe and efficient pressurization system is a crucial priority.

To this end, The Edge fuselage will incorporate an extensive system of crack propagation stoppers as discussed in Structures, Section 11.0. The Edge's elimination of windows (with the exception of emergency doors) also aids in a more economical, and therefore, a safer design since this in effect reduces the number of structurally critical areas dramatically. The Edge fuselage will be pressurized to an equivalent altitude of 8,000 ft, providing a level of comfort competitive with today's 747-4002°. An illustration of the pressurized fuselage is shown in Figure 14.3.

The theme for The Edge equipment cooling and air conditioning systems will be one of efficiency and passenger comfort. These systems are included in the representation of Figure 14.1. Multi-zone automatic temperature control will be employed in the cabin and cockpit areas, utilizing what is likely to be a liquid-coolant based cooling system pending state-of-the-art improvements by the year 2015. Heating of the cargo compartment and/or the cabin areas may be effected using heat from the outer aircraft surfaces. Efficiency in the pneumatic system design will be achieved by using engine bleed air for only half of the conditioned air volume; the remaining half will be generated through recirculated air filtering 20.

_-- FORWARD PRESSIJq_E BULKHEAD \ '\ \,, \ AFTPRESSURE BULKHEAD '---_ Figure 14.3 The Edge Pressurized Fuselage Representation 14.4 Flight Control System Please refer to Section 13.6., Stability and Control 14.5 Emergency Systems The Edge aircraft is equipped with current state of the art emergency systems in the event of an emergency. In the event of a cabin pressurization failure, oxygen is provided for all occupants. The flight crew is provided with a gaseous oxygen cylinder and two oxygen masks. The passengers, flight attendants and observers are provided with chemical oxygen. If depressurization occurs the chemical oxygen masks will be automatically deployed; an alternate manual deployment is also provided. Additionally, two portable oxygen bottles are to be located at each flight attendant's station 21.

If evacuation from the aircraft is required, there are nine exits including: two forward loading doors, two aft loading doors, four over-wing emergency doors, one overhead flight deck emergency hatch. Inflatable slides are provided at all four loading doors andthe two aft emergency doors which will deploy automatically when an emergency door is opened as shown in Figure 14.4. In addition, a manual override is provided to either open the emergency doors without deploying the slides or deploy any number of slides in the event that an emergency door can not be opened. The evacuation will be aided by the nose gear strut retracting to its loading position automatically with the deployment of a slide 21. This retraction is fail-safe, since it will be effected under the weight of the nose itself; a manual override will be provided to ensure nose gear retraction.

14.6 Synthetic Vision System Adequate flight crew vision is challenging to provide in supersonic transport designs, in that aerodynamic concerns requinng long and slender noses conflict with vision needs necessitating extensive viewports nearly perpendicular to the oncoming flow. The Edge meets this challenge with a comprehensive synthetic vision system.

There are few methods by which to circumvent the aforementioned problem, one of which is the droop-nose design used by the Aerospatiale Concorde 27- Unfortunately, this compromise includes significant weight penalties, and its benefits are only utilized upon landing. As another alternative, the flight deck window can be designed at appropriate angles for acceptable vision, regardless of aerodynamic penalties; however, these penalties are substantial.

It would be naive to insist that a synthetic vision system is an ideal alternative.

Its compromises include a substantial reliance on electronics and artificial optical networks, and the likelihood af substantial expenditures for FAA certification. On the other hand, such a system has the potential to significantly increase the pilots' viewing capabilities, while also serving as an appealing passenger amenity by way of individual, interchangeable LCD screens placed at all seats in the main cabin. Moreover, there are no substantial weight or drag penalties associated with a synthetic vision system. On balance, the benefits of such a system appear to clearly outweigh the detriments.

The Edge will utilize this type of vision arrangement, while attempting to address the issues of systems reliability and overall safety. First, the see-by-wire or see-by-light system will incorporate substantial redundancy. Second, a mechanical backup system will be designed in addition to flight deck windows; in particular, this backup will be in the form of a gravity-dropped periscope which will lock into place beneath the cockpit fuselage area in emergency situations, and allow limited though crucial forward flight vision.

The synthetic vision system itself will be used in the form of a head's-up display (HUD), whereby the views naturally blocked from the pilots' eyes by the aircraft nose will be seen by means of artificial images projected onto a screen below, and extending up to the bottom of, the flight deck window. This screen can be seen clearly in Figure 14.5.

14.7 Flight Deck The Edge SST is a state-of-the-art commercial aircraft which will begin service in the year 2015. The two-pilot flight deck of this aircraft will therefore be a product of the future, incorporating fly-by-wire or even fly-by-light avionics, and a comprehensive synthetic vision system as described above in Section 14.6.

Additionally, the flight deck as shown in Figure 14.5 will include the use of head's-up displays (HUDs) situated on the flight deck window, providing all critical flight information at an infinite focal point on the pilots' horizon; and while this HUD and the HUD described in Section 14.6 will provide the largely intangible benefit of increased flight safety, they may also translate into a tangible easing of vision requirements by the FAA, since HUD systems will allow superior vision in poor weather environments 23. Of course, multiple LCD displays will be provided in the cockpit to supplement the functions of the HUD.

jl J rlig|t laq_tt C?,te t ,..J Lj, Figure 14.5 The Edge Flight Deck

15.0 AIRPORT MAINTENANCE AND

OPERATION

15.0 Airport Maintenance and Operation

15.1 AirpOrt Maintenance The Edge is designed to be compatible for use in all existing major airports. This means that it will require no special fueling, cargo handling, servicing, or maintenance provisions. In particular, The Edge provides roughly equivalent airport compatibility to that of the currently popular 747-400.

Figure 15. l(a) shows the servicing arrangement utilized by The Edge during stop- overs, and Figure 15.1 (b) shows a modified configuration for turnaround servicing.

Figure 15.1 (a) The Edge Stop-Over Servicing Arrangement

Figure 15.2(b)

The Edge Turnaround Servicing Arrangement 15.2 Airport Operation In order to deliver the maximum benefits of The Edge's time-saving flights to its customers and operators, it has been designed for minimum stop-over and turnaround times. Table 15.1 illustrates a temporal representation of The Edge's stop-through service procedure. It is notable that The Edge will be able to stop for fuel and take off again within 45 minutes 20. As well, Table 15.2 presents a similar diagram for turnaround times. Once again, efficiency is the prevailing concern.

Table 15.1 The Edge Stop-Over Servicing Breakdown 2° IL Engine Shutdown ]_] Peamimger Service Position Pass Bridge/Stairs Deplane Passengers-40 per minute" Service Cabin I, 15r Service Galleys ! 1_1 Board Passengers-30 per minute" Remove Pass Bridge/Stairs Baggage Service

t--'c-'t

Unload Containers Load Containers Airplane Servioe I, 111 Fuel Airplane-8,800 gals" Engine Start 10 15 20 25 30 35 40 0 5 II Elapsed Time (Minutes) • 800 gels per minute ** 1000 load factor 50% exchange of passengers Table 15.2 The Edge Turnaround Servidng Breakdown 20 I F._,,e Shu_own Iq.menger Setvlae pot_. pa. Or_g_S_ Deplane Palam,¢tgors-40 _ minute "° _IP_ C4_ I 22 i CmJleyl I 29' '] Board Pmmengers-30 per minute "" r T n 1 Remove Pus Bridge/Stalral Baggage Servi_e Unload Containers I 1 A i Load Cont_ners | _ a ' I Alrpbme Sendce Fuel Airphlne-17,600 pls" Service Lmvstoriee Serv0ce Potal_e Water z_-zL__s_,__ 0 5 10 15 20 25 30 35 40 45 50 I I Elapud Time (MinutN) "OO0 gale per minute ""100% load Factor It should be clear from these tables that fueling is a major influence on ground servicing times. One aid in reducing these times, however, is the exclusive use of LD-W baggage containers; these allow the quick and efficient transfer of passenger belongings.

16.0 MANUFACTURING

16.0 Manufacturing

Planning the manufacturing process entails organizing the material flow, so that everything is in the proper place at the proper time. As well, major aircraft sections must be constructed from several smaller parts in order to yield a maximum production rate.

Close tolerances and careful planning must always be used when constructing an aircraft, in order that it will not only meet all the requirements, but also be safe.

Since The Edge will be largely constructed of titanium or other exotic materials, forming and machining will be relatively difficult and expensive. To help reduce manufacturingcosts, parts will be made right/left interchangeable whenever possible. Of course, many of the several million aircraft pieces and components will be subcontracted, entering The Edge factory in finished form.

The assembly of The Edge will occur in several phases, similar to the assembly of modem transport aircraft. Figure 16.1 allows a glimpse of these steps, which include the assembly of the six fuselage sections, and the subsequent attachment of the vertical tail and wing surfaces to the full fuselage.

The most dramatic excursion from current manufacturing processes occurs in the attachment of The Edge wing tips to the main wing. First, the wing tips are fitted with heating blankets to expand the fitting material. While this is being done, the pins are frozen in liquid nitrogen. These processes take approximately fifteen minutes, after which the tips are slipped into position, and the joint is allowed to swell for an interference fit 33.

Although this process may appear exotic, it is actually no more than an extension of methods being used today. That is, liquid nitrogen freezing, as well as the preheating of parts is common, though not typically on such a large scale. Aside from this, however, The Edge will be constructible using contemporary methods, thus aiding in the ultimate goal of low overall cost.

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17.0 COST ANALYSIS

17.0 Cost Analysis

The economic viability of a Supersonic Transport (SST) is of the upmost concern for The Edge design team. Due to the plane's extensive use of high technology materials, the manufacturing techniques will be the very latest available to the airframe builder. A cost analysis is performed here based on contemporary commercial transports for manufacturing and operating costs 30 using 1989 dollars. The Edge economic study is scaled to 1992 dollars using a Cost Escalation Factor (CEF), and a price of $167 million per aircraft is determined for a production run of 400 supersonic transports.

17.1 Costs for Research, Development, Test, and Evaluation The cost for research, development, test, and evaluation (RDT&E) is based on an Aeronautical Engineering Manufacturer's Planning Report (AEMPR) value of 205,000 lbs. This is the weight of the aircraft that the airframe manufacturer will be building. This cost is broken down into seven categories as shown in Figure 17.1.

0.09% 12.07% 25.30% 10.48%

I Development, Support and Testing

1.92% I[_ Right Test Planes [_ Right Test Operations [-'1 Right Test and Simulation 1 Profit Lml Financing 41.50% [] Prototype Figure 17.1 Summary of Research, Development, Testing and Evaluation Costs for The Edge

17.1.1 Engineering and Design Cost

Based on the AEMPR, an estimation for the number of hours required for airframe engineering and design is 89 million hours. This translates into 8,000 engineers working for 5 and one half years. Producing a total of three aircraft for testing should be sufficient; one will be exclusively for flight test, and two for ground static tests.

Accounting for the design difficulties caused by the materials currently being considered, and offsetting these with future computer-aided design capabilities, a total cost for engineering and design is estimated at 570 billion dollars.

17.1.2 Development Support and Testing The cost for development and support for three aircraft is estimated at $350 million 30.

17.1.3 Flight Test The cost of building three flight test aircraft must include engine costs, avionics, materials, tooling, and quality control. An estimated 76 million hours will be required to build the tooling for manufacturing at 1992 tooling labor rates of $45 per hour. In addition, manufacturing labor rates of $35 dollars per hour and 47 million hours are estimated to build these test aircraft. Thus, a total projected flight test program cost of 574 million dollars will include the cost of the engines, avionics, tooling, manufacturing, materials, and quality control 30.

17.1.4 Flight Test Operations Aircraft flight testing operations for airworthiness and FAA certification is estimated at $26 million 30.

17.1.5 Test and Simulation Facilities Test and simulation facilities will provide a place for static ground testing and simulator testing for the pilots and avionics. This was estimated at 10% of the total cost for RDT&E 30

17.1.6 Profit and Financing

Adding a 10% for profit and an interest rate of 15% to the total cost for RDT&E will account for financing while allowing an acceptable profit margin. This estimate for profit is an approximate estimate and could range between 8% and 12%. Due to the high cost of an SST program, a consortium of companies and countries will doubtlessly be involved in the project, and the cost of financing will subsequently be affected by this influence 3o.

17.1.7 Prototype The first article prototype is estimated to cost $83.8 million. This amount reflects only the cost to manufacture one airframe, excluding engines and avionics. After all costs are taken into account for RDT&E, an estimation of the total program cost is approximately $580 billion 3o.

17.2 Manufacturing Cost and Acquisition Manufacturing cost and acquisition is delineated into four categories and will yield a projected cost for manufacturing as described below.

17.2.1 Airframe Engineering and Design Airframe engineering and design, including a production run of 200 aircraft results in an estimated airframe engineering and design cost of $12.3 billion 30.

17.2.2 Manufacturing Cost The manufacturing cost for a 300 seat SST consists of interior, tooling, materials, and quality control. Estimating an average value of $2000 per seat 30 results in $125 million for the interior. It must be noted that this is only an average and may fluctuate depending on the airline. A total manufacturing cost of $32.5 billion is estimated for the manufacture of 200 aircraft at a production rate of 5 aircraft per month, allocating 10% of the total cost for quality control.

17.2.3Flight Testing

Flight testing must be performed for every aircraft manufactured. An operating

cost of $4,190 per hour and 10 hours of testing for each aircraft will cost approximately $35.5 million for 200 aircraft.

17.2.4 Financing Costs The cost of financing is challenging to estimate due to the fact that a consortium of countries will most likely be involved throughout the SST project. Therefore, although it may vary for different countries depending on their relative project involvements, an approximate f'mance cost is 15% of the total manufacturing debL Profit also fits into this category. No one country will be building an entire SST as a sole venture, so profits will be taken out of each manufacturing phase as it is completed. For the purpose of this design report, a 10% profit margin will be assessed to the total cost of manufacturing.

The total cost of manufacturing 200 SST aircraft is estimated to be $52 billion.

17.3 Direct and Indirect Operating Cost Direct and indirect operating cost is divided into several categories as illustrated below.

1.4_ 3_z1% 40.39% Figure 17.2 Summary of Operating Costs for The Edge 17.3.1 Flying Flying the aircraft incurs several costs, including flight crew, fuel and oil, and insurance. As previously explained, a crew of two will fly The Edge . Use of this minimal crew will cut operating costs. The cost incurred by the crew includes their salaries, travel expenses, vacation, sick leave, insurance and miscellaneous expenses.

Average salaries for the captain and first officer are estimated at $150,000 and $70,000, respectively (1992 doUars) 30. Considering the costs mentioned and flying 750 hours annually yields a flight crew cost of $0.46 per nautical mile. Fuel and oil costs are substantial to an airline; at a fuel cost of $0.60 per gallon and oil at $15 per gallon, the total costs for fuel and oil are estimated at $0.31 per nautical mile. Additionally, insurance is estimated at $0.03 per nautical mile. This projects a total flying cost of $0.80 per nautical mile.

17.3.2 Maintenance Maintenance of the airframe and engines is essential to the safety of the passengers and crew. The man-hours required to maintain an aircraft of this size total approximately 21.7 per hour of flight time. Materials for engine maintenance is the largest expense at $356 per hour of flight time. Combining the cost for labor and materials for the airframe will bring the total cost for maintenance to $46,344 per hour of flight time 30.

17.3.3 Depreciation Depreciation allows the airline to know how much its investment is worth after the aircraft has served its life cycle. This cost includes the depreciation of the airframe, engines, avionics and spare parts. The depreciation period is difficult to project due to the high speed and exotic aircraft materials being used. This period has been projected to 10 years for the airframe, 7 years for the engines and 5 years for the avionics. The total depreciation of The Edge is estimated at $8.92 per nautical mile 30.

17.3.4 Fees Fees for landing, navigation, and various taxes will vary since the plane is designed for intercontinental travel. Expenses incurred as the aircraft travels internationally and uses each county's navigational equipment are difficult to estimate due to the fact that fees differ in different countries and are levied in different ways. An average cost for this has been estimated at $0.32 per nautical mile 3o.

17.3.5 Financing The means by which each airline is financed is dependent upon the country of its operation and the condition of the overall market. An average f'mance cost has been estimated at 7%. The total direct operating cost of The Edge SST is estimated to be $23.62 per nautical mile 3o.

The aircraft cost model outlined in Reference 30 yields a statistical price of $240 million per aircraft based on the gross takeoff weight 30. The Edge cost analysis yields a cost of $167 million per aircraft (in 1992 dollars) for a production run of 400 supersonic transports, as can be seen in Figure 17.3.

1 ._9 1.0e*9 Price per Aircraft 5.0e+8 0.0e+0 0 100 200 300 400 500 600 700 800 900 1000 Number of Aircraft Figure 17.3 The Edge Price per Aircraft vs Production Number

18.0 CONCLUSION

18.0 Conclusion

The Edge supersonic transport aircraft is designed specifically to capture a substantial share of the international travel market, particularly in the trans-pacific and trans-Atlantic areas. As a result of this, it is comparable to its main competitor, the 747- 400, with regards to ergonomic, service, maintenance, and airport compatibility considerations. Moreover, at a cruise speed of M = 2.4, The Edge provides the remarkable benefit of cutting travel times for its 294 passengers in half for distances reaching up to 5750 rim.

The Edge is a futuristic design, in that it will not begin service until the year 2015. It is expected by this time that engine SFC values of 1.0 will be achievable, and that pollutants destructive to the stratosphere will be reduced dramatically, making The Edge fully environmentally compatible. In consideration of established aircraft noise limits, The Edge will also be able to meet all FAR Part 36, Stage III noise requirements.

However, excessive over-pressure levels generated in supersonic cruise will likely inhibit The Edge's ability to fly supersonically over land; while on the other hand, with a subsonic cruise I.,/D = 11, The Edge will be able to perform efficient subsonic flights overland.

The Edge clearly rides the outer limits of technology. Utilizing a fly-by-light flight control system, an advanced synthetic flight vision system, and new-age materials, The Edge is indeed a revolutionary transport. But it is not without technical hot-spots, the most significant of which is the weight of The Edge's wing tip load transfer structures. It is therefore in the materials and structural areas that technological improvements will be most helpful in confh'ming The Edge as a second generation supersonic transport possibility. For as these areas improve, so will the overall economic feasibility of the aircraft itself.

The Edge shows an education from past errors. Specifically, it represents a design methodology focused on economic viability. And from this preliminary view, it does seem feasible With a production run of 400 aircraft, The Edge will be sold for $167 million per transport.

19.0 REFERENCES

19.0 References

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