14th AlAA/AHI Space Planes and Hypersonic Systems and Technologies Conference AIAA2006-7984 ALAA2006-7984 Preliminary Definition of Supersonic and Hypersonic Airliner Configurations Martin Sippel',Josef Klevanski Space Launcher Systems Analysis(SART),DLR,51170 Cologne,Germany The propulsion system investigations of the EU sponsored LAPCAT study require the definition of generic reference vehicles to e.g.define the thrust level or assess a specific engine performance considering the reference mission of non-stop Brussels to Sydney flight. This paper describes DLR's Space Launcher Systems Analysis SART group's iterative definition of two configurations:The generic supersonic cruise airplane for a cruise Mach number of about four(designated LAPCAT-M4)is considerably enlarged compared to an earlier NASA design to meet the ambitious range requirement.Its propulsion system is based on Turbo-RAM with JP-propellant.The generic hypersonic Mach 8 cruise airplane (LAPCAT-M8)has been initially based on an innovative concept dubbed HyperSoar.The latter configuration uses hydrogen as fuel and an RBCC propulsion system.The paper gives an overview on the recent conceptual design status of the two passenger cruise vehicles presenting geometrical size and mass data and describing results of trajectory simulations and thus actually achievable range.Crucial system related design issues of the propulsion system,especially for the RBCC,will be discussed and critically assessed.Finally,an alternative technical option for high speed intercontinental passenger transport without air- breathing propulsion will be presented as a competitive benchmark. Nomenclature D Drag N M.Ma Mach-number T Thrust N W weight N 1 body length 今 m mass kg 9 dynamic pressure Pa sfe specific fuel consumption g/kNs sfr fuel consumption per range kg/km angle of attack flight path angle expansion ratio Subscripts,Abbreviations CAD computer aided design CFD Computational Fluid Dynamics CFRP Carbon Fiber Reinforced Polymer EASA European Aviation Safety Agency FAA Federal Aviation Administration GLOW Gross Lift-Off Mass 'Department Head,Space Launcher Systems Analysis(SART),DLR,51170 Cologne,Germany,Member AIAA "Aerospace Engineer,Space Launcher Systems Analysis(SART),DLR,51170 Cologne,Germany 1 American Institute of Aeronautics and Astronautics Paper 2006-7984 Copyright2006 by DLR-SART.Published by the American Institute of Aeronautics and Astronautics,Inc.,with permission
American Institute of Aeronautics and Astronautics Paper 2006-7984 1 AIAA 2006-7984 Preliminary Definition of Supersonic and Hypersonic Airliner Configurations Martin Sippel* , Josef Klevanski** Space Launcher Systems Analysis (SART), DLR, 51170 Cologne, Germany The propulsion system investigations of the EU sponsored LAPCAT study require the definition of generic reference vehicles to e.g. define the thrust level or assess a specific engine performance considering the reference mission of non-stop Brussels to Sydney flight. This paper describes DLR’s Space Launcher Systems Analysis SART group’s iterative definition of two configurations: The generic supersonic cruise airplane for a cruise Mach number of about four (designated LAPCAT-M4) is considerably enlarged compared to an earlier NASA design to meet the ambitious range requirement. Its propulsion system is based on Turbo-RAM with JP-propellant. The generic hypersonic Mach 8 cruise airplane (LAPCAT-M8) has been initially based on an innovative concept dubbed HyperSoar. The latter configuration uses hydrogen as fuel and an RBCC propulsion system. The paper gives an overview on the recent conceptual design status of the two passenger cruise vehicles presenting geometrical size and mass data and describing results of trajectory simulations and thus actually achievable range. Crucial system related design issues of the propulsion system, especially for the RBCC, will be discussed and critically assessed. Finally, an alternative technical option for high speed intercontinental passenger transport without airbreathing propulsion will be presented as a competitive benchmark. Nomenclature D Drag N M, Ma Mach-number - T Thrust N W weight N l body length m m mass kg q dynamic pressure Pa sfc specific fuel consumption g/kNs sfr fuel consumption per range kg / km α angle of attack - γ flight path angle - ε expansion ratio - Subscripts, Abbreviations CAD computer aided design CFD Computational Fluid Dynamics CFRP Carbon Fiber Reinforced Polymer EASA European Aviation Safety Agency FAA Federal Aviation Administration GLOW Gross Lift-Off Mass * Department Head, Space Launcher Systems Analysis (SART), DLR, 51170 Cologne, Germany, Member AIAA ** Aerospace Engineer, Space Launcher Systems Analysis (SART), DLR, 51170 Cologne, Germany 14th AIAA/AHI Space Planes and Hypersonic Systems and Technologies Conference AIAA 2006-7984 Copyright © 2006 by DLR-SART. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission
HSCT High Speed Civil Transport JP (hydrocarbon)Jet Propellant(kerosene) LAPCAT Long-Term Advanced Propulsion Concepts and Technologies LH2 Liquid Hydrogen LLNL Lawrence Livermore National Laboratory LOX Liquid Oxygen MECO Main Engine Cut Off OPR Overall Pressure Ratio RBCC Rocket Based Combined Cycle SERN semi expansion ramp nozzle SST Supersonic Transport TBCC Turbine Based Combined Cycle TET Turbine Entry Temperature TRL Technology Readiness Level VCE Variable Cycle Engine cog center of gravity 0.0 sea-level,static I.Introduction The EU sponsored LAPCAT study investigates different types of advanced propulsion systems for supersonic and hypersonic cruise airplanes.LAPCAT addresses advanced high-speed air-breathing propulsion concepts.The first scientific and technological objective of the multinational research project is further outlined in [1]as: "..to evaluate two advanced airbreathing concepts:a Turbine or Rocket Based Combined Cycle (TBCC/RBCC) capable of achieving the ultimate goal to reduce long-distance flights,e.g.from Brussels to Sydney,to less than 2 to 4 hours.Two reference vehicles including their characteristic trajectory points have to be established." In LAPCAT the definition of both reference vehicles and their trajectories has been performed by DLR-SART.The statement on the Brussels to Sydney route translates into a range requirement of at least 16700 km along the orthodrome and hypersonic flight conditions. The design approach has been structured as: Identification of past projects on similar hypersonic cruise airplanes Critical recalculation of the past projects Definition of the baseline flight vehicles by adaptation and improvement of the investigated concept Iterative vehicle adaptation,taking into account latest,more elaborate data of LAPCAT propulsion work packages II.Supersonic Cruise Airplane at Mach 4.5 A.NASA Langley and Lockheed Mach 4 Airplane Study In 1990 NASA Langley and Lockheed Engineering Sciences Company conducted a study to configure and analyze a 250-passenger,Mach 4 high-speed civil transport with a design range of 6500 nautical miles(12045.8 km) [4].The design mission assumed an all-supersonic cruise segment and no community noise or sonic boom constraints.The study airplane was developed in order to examine the technology requirements for such a vehicle and to provide an unconstrained baseline from which to assess changes in technology levels,sonic boom limits,or community noise constraints in future studies 4. The general arrangement of the airplane is illustrated in Figure 1.The concept employs a blended wing-body with a modified blunt nose,a highly swept inboard wing panel,and a moderately swept outboard wing panel with curved,raked wingtips.Total length of the vehicle reaches almost 95 m. 2 American Institute of Aeronautics and Astronautics Paper 2006-7984
American Institute of Aeronautics and Astronautics Paper 2006-7984 2 HSCT High Speed Civil Transport JP (hydrocarbon) Jet Propellant (kerosene) LAPCAT Long-Term Advanced Propulsion Concepts and Technologies LH2 Liquid Hydrogen LLNL Lawrence Livermore National Laboratory LOX Liquid Oxygen MECO Main Engine Cut Off OPR Overall Pressure Ratio RBCC Rocket Based Combined Cycle SERN semi expansion ramp nozzle SST Supersonic Transport TBCC Turbine Based Combined Cycle TET Turbine Entry Temperature TRL Technology Readiness Level VCE Variable Cycle Engine cog center of gravity 0,0 sea-level, static I. Introduction The EU sponsored LAPCAT study investigates different types of advanced propulsion systems for supersonic and hypersonic cruise airplanes. LAPCAT addresses advanced high-speed air-breathing propulsion concepts. The first scientific and technological objective of the multinational research project is further outlined in [1] as: "… to evaluate two advanced airbreathing concepts: a Turbine or Rocket Based Combined Cycle (TBCC/RBCC) capable of achieving the ultimate goal to reduce long-distance flights, e.g. from Brussels to Sydney, to less than 2 to 4 hours. Two reference vehicles including their characteristic trajectory points have to be established." In LAPCAT the definition of both reference vehicles and their trajectories has been performed by DLR-SART. The statement on the Brussels to Sydney route translates into a range requirement of at least 16700 km along the orthodrome and hypersonic flight conditions. The design approach has been structured as: • Identification of past projects on similar hypersonic cruise airplanes • Critical recalculation of the past projects • Definition of the baseline flight vehicles by adaptation and improvement of the investigated concept • Iterative vehicle adaptation, taking into account latest, more elaborate data of LAPCAT propulsion work packages II. Supersonic Cruise Airplane at Mach 4.5 A. NASA Langley and Lockheed Mach 4 Airplane Study In 1990 NASA Langley and Lockheed Engineering & Sciences Company conducted a study to configure and analyze a 250-passenger, Mach 4 high-speed civil transport with a design range of 6500 nautical miles (12045.8 km) [4]. The design mission assumed an all-supersonic cruise segment and no community noise or sonic boom constraints. The study airplane was developed in order to examine the technology requirements for such a vehicle and to provide an unconstrained baseline from which to assess changes in technology levels, sonic boom limits, or community noise constraints in future studies [4]. The general arrangement of the airplane is illustrated in Figure 1. The concept employs a blended wing-body with a modified blunt nose, a highly swept inboard wing panel, and a moderately swept outboard wing panel with curved, raked wingtips. Total length of the vehicle reaches almost 95 m
Four advanced afterburning turbojet engines are mounted in two nacelles on the wing lower surface adjacent to the fuselage.The propulsion system selected for the NASA-study consists of four conceptual single-rotor, augmented(afterburning)turbojets using thermally stabilized jet fuel. The Lockheed-NASA estimated dry weight is given at 130 Mg and with 288 Mg kerosene propellant the total lift-off weight including crew,passengers,and their luggage reaches 448 Mg.This mass estimation could not be fully attested by a DLR-SART calculation [2].In any case the LAPCAT mission range is by almost 40%larger than NASA's 12000 km,which requires a re-design. 1530 10.0 32s 12125 Figure 1:NASA Mach 4 supersonic cruise airplane proposal from 1990 [4](all dimensions in ft) B.LAPCAT-M4 The new supersonic cruise airplane has to be considerably enlarged compared to the earlier NASA design to meet its ambitious range requirement.To keep the wing loading in an acceptable range the wing size has been increased to 1600 m2(+36%).The span grows almost proportionally by 16%,while the total length reaches 102.78 m which is only slightly longer(+8.8%)than the HSCT proposal. The general arrangement of the generic airplane geometry is illustrated in Figure 2 through Figure 4;principal geometric dimensions are presented in Table 1.The LAPCAT-M4 employs similar to the NASA concept a blended wing-body with a modified platypus nose,a highly swept inboard wing panel,and a moderately swept outboard wing panel (see Figure 3).The inboard wing panel is swept 78,allowing the flow component normal to its leading edge to remain subsonic even at the Mach 4.5 cruise condition.The high sweep allows relatively blunt leading edges without a substantial zero-lift wave drag penalty.The inboard leading edge has a fixed geometry,free of high-lift devices,resulting in a simpler and lighter wing structure.The outboard wing panel is swept 55 but its exact, possibly curved form has not been defined yet.The total wing is inclined with a positive angle of attack of approximately 2.75.Note that this angle and the wing's airfoil are not optimized yet and might be adapted,if required. The forebody of the concept is slender and elliptical in cross section.Like the NASA concept,the fuselage is windowless to simplify the structural design and environmental control.The wing-mounted struts of the main landing gear should retract into the engine nacelles and are housed between the inlet ducts as in [4].The two- wheeled nose gear is mounted on the bulkhead forward of the crew station and retracts forward. Four advanced turbo-RAM-jet engines are mounted in two nacelles on the wing lower surface adjacent to the fuselage.The location of the engine and nacelles is still open for adaptation if required by trim as long as they remain under the wing.The axial-symmetric geometry and the size of the air-intakes,nacelles and nozzles as shown in Figure 2 and Figure 4 are not representative of the actual LAPCAT design.A rectangular shape of the air-intake with vertical ramps as in [4]is the preferred design option.The detailed propulsion system definition is described in reference 3. Fuel is carried in integral wing tanks and in a single aft fuselage tank.It is further assumed that the vehicle uses thermally stabilized jet fuel (TSJF)because the existing airport infrastructure is designed around conventional jet fuel.A single vertical stabilizer is attached to the upper part of the aft fuselage(see Figure 2 and Figure 4). 3 American Institute of Aeronautics and Astronautics Paper 2006-7984
American Institute of Aeronautics and Astronautics Paper 2006-7984 3 Four advanced afterburning turbojet engines are mounted in two nacelles on the wing lower surface adjacent to the fuselage. The propulsion system selected for the NASA-study consists of four conceptual single-rotor, augmented (afterburning) turbojets using thermally stabilized jet fuel. The Lockheed-NASA estimated dry weight is given at 130 Mg and with 288 Mg kerosene propellant the total lift-off weight including crew, passengers, and their luggage reaches 448 Mg. This mass estimation could not be fully attested by a DLR-SART calculation [2]. In any case the LAPCAT mission range is by almost 40 % larger than NASA’s 12000 km, which requires a re-design. Figure 1: NASA Mach 4 supersonic cruise airplane proposal from 1990 [4] (all dimensions in ft) B. LAPCAT-M4 The new supersonic cruise airplane has to be considerably enlarged compared to the earlier NASA design to meet its ambitious range requirement. To keep the wing loading in an acceptable range the wing size has been increased to 1600 m2 (+ 36%). The span grows almost proportionally by 16 %, while the total length reaches 102.78 m which is only slightly longer (+ 8.8 %) than the HSCT proposal. The general arrangement of the generic airplane geometry is illustrated in Figure 2 through Figure 4; principal geometric dimensions are presented in Table 1. The LAPCAT-M4 employs similar to the NASA concept a blended wing-body with a modified platypus nose, a highly swept inboard wing panel, and a moderately swept outboard wing panel (see Figure 3). The inboard wing panel is swept 78°, allowing the flow component normal to its leading edge to remain subsonic even at the Mach 4.5 cruise condition. The high sweep allows relatively blunt leading edges without a substantial zero-lift wave drag penalty. The inboard leading edge has a fixed geometry, free of high-lift devices, resulting in a simpler and lighter wing structure. The outboard wing panel is swept 55° but its exact, possibly curved form has not been defined yet. The total wing is inclined with a positive angle of attack of approximately 2.75°. Note that this angle and the wing's airfoil are not optimized yet and might be adapted, if required. The forebody of the concept is slender and elliptical in cross section. Like the NASA concept, the fuselage is windowless to simplify the structural design and environmental control. The wing-mounted struts of the main landing gear should retract into the engine nacelles and are housed between the inlet ducts as in [4]. The twowheeled nose gear is mounted on the bulkhead forward of the crew station and retracts forward. Four advanced turbo-RAM-jet engines are mounted in two nacelles on the wing lower surface adjacent to the fuselage. The location of the engine and nacelles is still open for adaptation if required by trim as long as they remain under the wing. The axial-symmetric geometry and the size of the air-intakes, nacelles and nozzles as shown in Figure 2 and Figure 4 are not representative of the actual LAPCAT design. A rectangular shape of the air-intake with vertical ramps as in [4] is the preferred design option. The detailed propulsion system definition is described in reference 3. Fuel is carried in integral wing tanks and in a single aft fuselage tank. It is further assumed that the vehicle uses thermally stabilized jet fuel (TSJF) because the existing airport infrastructure is designed around conventional jet fuel. A single vertical stabilizer is attached to the upper part of the aft fuselage (see Figure 2 and Figure 4)
0 [w]Z 5 1 emt日 0102030405060708090100 X [m] Figure 2:LAPCAT-M4 projection in the x-z-plane(nacelle design not representative) 2 10 5 0 5 -10 6 20 25 30 0102030405060708090100 X [m] Figure 3:LAPCAT-M4 projection in the x-y-plane Z N 0 -5 ELLLL 30 20 10 0 -10 -20 -30 Y [m] Figure 4:LAPCAT-M4 projection in the y-z-plane(nacelle design not representative) The large,slightly inclined wing might help to achieve a good maximum L/D of 7.8 at a small angle of attack and cruise Mach number 4.5 according to preliminary DLR-analysis.Actually,a high L/D is essential to achieve the ambitious range requirement. The total take-off mass of the supersonic cruise airplane has been iterated in the first loop to the huge value of 702.6 Mg [2]and has been recently slightly increased to 720 Mg,which is well beyond any supersonic passenger aircraft built to date.The dry mass is estimated at 184.5 Mg and the structural index is at a for airplanes low 36.8 % According to current data the LAPCAT-M4 would be able to transport about 200 passengers with their luggage.The 4 American Institute of Aeronautics and Astronautics Paper 2006-7984
American Institute of Aeronautics and Astronautics Paper 2006-7984 4 Figure 2: LAPCAT-M4 projection in the x-z-plane (nacelle design not representative) Figure 3: LAPCAT-M4 projection in the x-y-plane Figure 4: LAPCAT-M4 projection in the y-z-plane (nacelle design not representative) The large, slightly inclined wing might help to achieve a good maximum L/D of 7.8 at a small angle of attack and cruise Mach number 4.5 according to preliminary DLR-analysis. Actually, a high L/D is essential to achieve the ambitious range requirement. The total take-off mass of the supersonic cruise airplane has been iterated in the first loop to the huge value of 702.6 Mg [2] and has been recently slightly increased to 720 Mg, which is well beyond any supersonic passenger aircraft built to date. The dry mass is estimated at 184.5 Mg and the structural index is at a for airplanes low 36.8 %. According to current data the LAPCAT-M4 would be able to transport about 200 passengers with their luggage. The
high sensitivity of the configuration to mass changes and the ambitious mass goals of some components should be noted. Table 1:Major geometrical data of the LAPCAT-M4 configuration LAPCAT-M4 overall length [m] 102.78 overall height [m] 11.45 fuselage diameter [m] 4.13 fuselage length (incl.Nose)[m] 102.78 wing span [m] 54.15 wing mean aerodynamic chord(MAC)[m] 29.54 wing inboard span [m] 24.29 maximum wing thickness chord [m] 1.5 exposed wing area [m2] 1600 wing leading edge sweep angle [deg. 78° wing trailing edge sweep angle [deg.] 5° wing outboard span [m] 29.86 wing outboard leading edge sweep angle [deg. 56° outboard trailing edge sweep angle [deg.] 30° fin height m] 5.11 fin mean aerodynamic chord(MAC)[m] 8.7 maximum fin thickness chord [m] 0.35 exposed fin area [m2] 44.5 fin leading edge sweep angle [deg.] 69° fin trailing edge sweep angle [deg. 30.0 nose radius [m] 0.055 aerodynamic reference area [m2] 1600 aerodynamic reference length [m] 102.77 The NASA selection of four conceptual single-rotor,augmented(afterburning)turbojets has been used as a baseline in the preliminary sizing of [2].However,the engine type is slightly changed from pure augmented turbojet to combined Turbo-RAM propulsion to enable an increased cruise Mach number of up to 4.5.A detailed critical description of the engine selection process including the investigation of advanced propulsion options using Variable Cycle Engines(VCE)are described in [3]. The complete flight trajectory of LAPCAT-M4 from take-off,via ascent,acceleration to the supersonic cruise descent and landing approach has been simulated using control algorithms described in [2].The calculation ends after depletion of nominal propellants with descent to sea-level altitude.The vehicle follows almost the orthodrome, however,with some deviations to avoid some densely populated areas,adding about 200 km to the shortest great circle route.It's no objective in LAPCAT to proof if the chosen track is actually acceptable for supersonic high altitude flight.Nevertheless,the propulsion system performance should be assessed under realistic operational conditions.Thus,a significant portion of the trajectory (from Brussels in eastern direction up to Volgograd)is assumed to be flown in subsonic cruise. Under these hypotheses LAPCAT-M4 with the available 484.8 Mg of JP-fuel does not fully reach its final destination Sydney but at least arrives after 15989 km in central Australia(145.9 E:26.4S).Flight time is 23811 s (6.6 h).It has not been intended to further enlarge the vehicle to finally fulfill the mission goal.Such work could be the subject ofa separate study while LAPCAT focuses on propulsion system research. Therefore,the obtained results demonstrate the principle feasibility of a TBCC-powered ultra long-haul supersonic airliner.The VCE-214 engine variant with relatively high OPR shows the best performance of all investigated types as long as potentially different engine masses are not taken into account [3].Figure 5 reveals some interesting features of the intercontinental cruise trajectory performance in the form of vehicle fuel American Institute of Aeronautics and Astronautics Paper 2006-7984
American Institute of Aeronautics and Astronautics Paper 2006-7984 5 high sensitivity of the configuration to mass changes and the ambitious mass goals of some components should be noted. Table 1: Major geometrical data of the LAPCAT-M4 configuration LAPCAT-M4 overall length [m] 102.78 overall height [m] 11.45 fuselage diameter [m] 4.13 fuselage length (incl. Nose) [m] 102.78 wing span [m] 54.15 wing mean aerodynamic chord (MAC) [m] 29.54 wing inboard span [m] 24.29 maximum wing thickness @ chord [m] 1.5 exposed wing area [m2 ] 1600 wing leading edge sweep angle [deg.] 78° wing trailing edge sweep angle [deg.] 5° wing outboard span [m] 29.86 wing outboard leading edge sweep angle [deg.] 56° outboard trailing edge sweep angle [deg.] 30° fin height [m] 5.11 fin mean aerodynamic chord (MAC)[m] 8.7 maximum fin thickness @ chord [m] 0.35 exposed fin area [m2 ] 44.5 fin leading edge sweep angle [deg.] 69° fin trailing edge sweep angle [deg.] 30.0 nose radius [m] 0.055 aerodynamic reference area [m2 ] 1600 aerodynamic reference length [m] 102.77 The NASA selection of four conceptual single-rotor, augmented (afterburning) turbojets has been used as a baseline in the preliminary sizing of [2]. However, the engine type is slightly changed from pure augmented turbojet to combined Turbo-RAM propulsion to enable an increased cruise Mach number of up to 4.5. A detailed critical description of the engine selection process including the investigation of advanced propulsion options using Variable Cycle Engines (VCE) are described in [3]. The complete flight trajectory of LAPCAT-M4 from take-off, via ascent, acceleration to the supersonic cruise, descent and landing approach has been simulated using control algorithms described in [2]. The calculation ends after depletion of nominal propellants with descent to sea-level altitude. The vehicle follows almost the orthodrome, however, with some deviations to avoid some densely populated areas, adding about 200 km to the shortest great circle route. It’s no objective in LAPCAT to proof if the chosen track is actually acceptable for supersonic high altitude flight. Nevertheless, the propulsion system performance should be assessed under realistic operational conditions. Thus, a significant portion of the trajectory (from Brussels in eastern direction up to Volgograd) is assumed to be flown in subsonic cruise. Under these hypotheses LAPCAT-M4 with the available 484.8 Mg of JP-fuel does not fully reach its final destination Sydney but at least arrives after 15989 km in central Australia (145.9° E; 26.4° S). Flight time is 23811 s (6.6 h). It has not been intended to further enlarge the vehicle to finally fulfill the mission goal. Such work could be the subject of a separate study while LAPCAT focuses on propulsion system research. Therefore, the obtained results demonstrate the principle feasibility of a TBCC-powered ultra long-haul supersonic airliner. The VCE-214 engine variant with relatively high OPR shows the best performance of all investigated types as long as potentially different engine masses are not taken into account [3]. Figure 5 reveals some interesting features of the intercontinental cruise trajectory performance in the form of vehicle fuel