longitudinal double wing (ldw) concept presented by michael dizdarevic aiaa aviation 2013 conference...
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Longitudinal Double Wing Longitudinal Double Wing (LDW) (LDW) ConceptConcept
Presented by Michael DizdarevicPresented by Michael Dizdarevic
AIAA Aviation 2013 Conference - Los AIAA Aviation 2013 Conference - Los AngelesAngeles
Aug 13, 2013 2Longitudinal Double Wing (LDW) Aircraft
AgendaAgenda About the research teamAbout the research team Introduction of LDW conceptIntroduction of LDW concept General aircraft classification and characteristicsGeneral aircraft classification and characteristics LDW configuration and characteristicsLDW configuration and characteristics Similarities and differences between LDW and Similarities and differences between LDW and
tube-and-wing (TAW) aircrafttube-and-wing (TAW) aircraft Architectural impact on aircraft performanceArchitectural impact on aircraft performance Case study (LDW-200 vs. B767-300ER)Case study (LDW-200 vs. B767-300ER) Assumptions and MethodologyAssumptions and Methodology ResultsResults ConclusionConclusion Q & A Q & A
Aug 13, 2013 3Longitudinal Double Wing (LDW) Aircraft
About Research TeamAbout Research TeamFARUK DIZDAREVICFARUK DIZDAREVIC (Principal Researcher) (Principal Researcher)
VP R&D Soko Aircraft Industry – the largest aircraft company in VP R&D Soko Aircraft Industry – the largest aircraft company in former Yugoslavia. former Yugoslavia.
Previously a head of company’s Aircraft and Helicopter divisions Previously a head of company’s Aircraft and Helicopter divisions involving manufacturing of their own military training and combat involving manufacturing of their own military training and combat aircraft, as well as various components for World’s major aircraft aircraft, as well as various components for World’s major aircraft including B737/757, MD-80, and A310/330/340, etc.including B737/757, MD-80, and A310/330/340, etc.
University professor in the area of aircraft manufacturing University professor in the area of aircraft manufacturing technologies for many years. technologies for many years.
Extensive experience and expertise related to the research of Flying Extensive experience and expertise related to the research of Flying Wing aerodynamic concepts for the past 20+ years. Wing aerodynamic concepts for the past 20+ years.
Holder of a number of U.S. patents related to aeronautics field. Holder of a number of U.S. patents related to aeronautics field.
Aug 13, 2013 4Longitudinal Double Wing (LDW) Aircraft
About Research Team About Research Team ……cont.cont.
MICHAEL DIZDAREVICMICHAEL DIZDAREVIC (Researcher ) (Researcher )
Research of Flying Wing aerodynamic concepts for the past 20+ Research of Flying Wing aerodynamic concepts for the past 20+ years. years.
Versatile University level educational background in Mechanical and Versatile University level educational background in Mechanical and Aeronautical Engineering, as well as Finance and Computer Aeronautical Engineering, as well as Finance and Computer Science. Science.
Extensive work experience with large scale data processing, Extensive work experience with large scale data processing, integration, modeling, and analysis with major US and international integration, modeling, and analysis with major US and international corporations including project management for the past 15 years. corporations including project management for the past 15 years.
Aug 13, 2013 5Longitudinal Double Wing (LDW) Aircraft
General Aircraft General Aircraft ClassificationClassification
Achieve good aerodynamic characteristics
Improved aircraft features relative to both TAW and
TFW aircraft
Achieve good aerodynamic characteristics of TAW
aircraft
High level of natural longitudinal stability
High level of flight control efficiency in all flight
conditions
High level of ride quality
Higher engine efficiency relative to both TAW and
TFW aircraft
Lower airfoil thickness than both TAW and TFW aircraft
Lower level of noise in passenger cabin and
around airports
Reduce parasitic wetted area of aircraft
Achieve high ratio between airlifting and total wetted
area
Favorable distribution between aerodynamic and inertia forces to generate low bending momentums
Longitudinal Double Wing (LDW) Aircraft Goals
Additional Goals
Use of efficient aft-camber airfoils across the wing
span
Favorable aircraft shapes to allow for application of light composite materials across the entire airframe
Tube And Wing (TAW) Aircraft
Hybrid AircraftTailless Flying
Wing (TFW) Aircraft
Goals Goals
Aug 13, 2013 6Longitudinal Double Wing (LDW) Aircraft
LDW Aerodynamic ConceptLDW Aerodynamic ConceptVisualizationVisualization
Aug 13, 2013 7Longitudinal Double Wing (LDW) Aircraft
LDW ConfigurationLDW Configuration
Front Wing
Architectural Configuration
V-tail Rear Wing
Aug 13, 2013 8Longitudinal Double Wing (LDW) Aircraft
Aircraft CharacteristicsAircraft Characteristics
Accommodation of 90% of installations, instruments,
and equipment
Landing Gear Accommodation
Roll control of aircraft in all flight configurationsFuel Disposal
Production of extra lift needed at low speed during
take-off and landingPayload Disposal
Production of 80% of necessary lift in cruising
flight configurationCockpit
Aerodynamics
Front Wing (FW)
Architecture
Aug 13, 2013 9Longitudinal Double Wing (LDW) Aircraft
Aircraft Characteristics Aircraft Characteristics ……cont.cont.
Pitch and roll control in all flight configurations
Participating in overall lift production of up to 20% in
cruise conditions
Accommodation of installations and
instruments required for engine operations and
flight control
Natural longitudinal stabilization of LDW
aircraft
Accommodation of aircraft engines
Aerodynamics
Rear Wing (RW)
Architecture
Pitch trimming in all flight configurations
Aug 13, 2013 10Longitudinal Double Wing (LDW) Aircraft
Aircraft Characteristics Aircraft Characteristics ……cont.cont.
Yaw control of LDW aircraft
Accommodation of installations traversing
between Front and Rear Wing
Longitudinal and directional natural
stabilization of LDW aircraft
Reliable and safe connection between Front
and Rear Wing
Aerodynamics
V-tail (VT)
Architecture
Aug 13, 2013 11Longitudinal Double Wing (LDW) Aircraft
LDW and TAW LDW and TAW SimilaritiesSimilarities Both aircraft having pronounced separate front and rear Both aircraft having pronounced separate front and rear
aerodynamic surfaces for lift production and reliable flight aerodynamic surfaces for lift production and reliable flight controlscontrols
The ratio between rear and front aerodynamic surfaces is The ratio between rear and front aerodynamic surfaces is rather close at around 0.5 for both aircraftrather close at around 0.5 for both aircraft
Span and overall length of both aircraft for a given aircraft Span and overall length of both aircraft for a given aircraft category are rather closecategory are rather close
Resulting similar flight control efficiencyResulting similar flight control efficiency
Aug 13, 2013 12Longitudinal Double Wing (LDW) Aircraft
LDW and TAW LDW and TAW DifferencesDifferences
Different shape, size, architecture, and aerodynamic Different shape, size, architecture, and aerodynamic tasks of connecting bodies (V-tail and fuselage tasks of connecting bodies (V-tail and fuselage respectively)respectively)
Different inner shape, payload distribution, and Different inner shape, payload distribution, and structural integration with other sections, as well as structural integration with other sections, as well as different aerodynamic function of payload bay.different aerodynamic function of payload bay.
Aug 13, 2013 13Longitudinal Double Wing (LDW) Aircraft
LDW and TAW LDW and TAW Differences Differences …cont.…cont. Different design and position of engines’ aerodynamic cover , as Different design and position of engines’ aerodynamic cover , as
well as integration with other aircraft sectionswell as integration with other aircraft sections Different size and flight mechanics task of rear aerodynamic Different size and flight mechanics task of rear aerodynamic
surfacessurfaces Different size of front aerodynamic surfaces for the same class Different size of front aerodynamic surfaces for the same class
aircraftaircraft
Aug 13, 2013 14Longitudinal Double Wing (LDW) Aircraft
Architecture Architecture Performance ImpactPerformance Impact
Aug 13, 2013 15Longitudinal Double Wing (LDW) Aircraft
Architecture Architecture Performance ImpactPerformance Impact
Aug 13, 2013 16Longitudinal Double Wing (LDW) Aircraft
Architecture Architecture Performance ImpactPerformance Impact
Aug 13, 2013 17Longitudinal Double Wing (LDW) Aircraft
Architecture Architecture Performance ImpactPerformance Impact
Aug 13, 2013 18Longitudinal Double Wing (LDW) Aircraft
Architecture Architecture Performance ImpactPerformance Impact
Aug 13, 2013 19Longitudinal Double Wing (LDW) Aircraft
Case study (LDW-200 vs. Case study (LDW-200 vs. B767)B767)
Dimensional analysis was performed to Dimensional analysis was performed to identify the separate impact of each identify the separate impact of each architectural element on aircraft architectural element on aircraft performanceperformance
Comparison case study was performed Comparison case study was performed for B767-300ER long-range version and for B767-300ER long-range version and the equivalent virtual LDW-200 aircraft the equivalent virtual LDW-200 aircraft with similar exploitation characteristicswith similar exploitation characteristics
Aug 13, 2013 20Longitudinal Double Wing (LDW) Aircraft
Assumptions and Assumptions and MethodologyMethodology
Assumptions
Operating Weight Empty
Calculations
Flight Control
Efficiency Ratio
Calculation
Longitudinal Double Wing (LDW) Aircraft
Fuel Weight and Drag
Ratio Calculation
s
Specific Fuel
Consumption Ratio
Calculation
Calculation Methodology
Aug 13, 2013 21Longitudinal Double Wing (LDW) Aircraft
AssumptionsAssumptions Both aircraft flying at the same speed and Both aircraft flying at the same speed and
altitudealtitude Same operating rangeSame operating range Same airfoil familySame airfoil family Constant CConstant CLL across the span, hence Mean across the span, hence Mean
Aerodynamic Chord (M.A.C.) becoming Aerodynamic Chord (M.A.C.) becoming identical to Mean Geometric Chord (M.G.C.) for identical to Mean Geometric Chord (M.G.C.) for dimensional analysis purposesdimensional analysis purposes
Roughly the same space for payload Roughly the same space for payload accommodationaccommodation
Same engine efficiencySame engine efficiency
Aug 13, 2013 22Longitudinal Double Wing (LDW) Aircraft
Calculation MethodologyCalculation Methodology Fuel weight of B767-300ER aircraft was taken as a Fuel weight of B767-300ER aircraft was taken as a
difference between Max. T.O. weight and the sum of difference between Max. T.O. weight and the sum of operating empty weight and Max. payload weightoperating empty weight and Max. payload weight
Weights of LDW-200 airframe sections were Weights of LDW-200 airframe sections were calculated by Stanford University methodology for calculated by Stanford University methodology for commercial aircraft and then modified by taking into commercial aircraft and then modified by taking into consideration that 75% of airframe was made of consideration that 75% of airframe was made of composites except for Cabin and Rear Wing, which composites except for Cabin and Rear Wing, which were calculated based on NASA’s BWB methodologywere calculated based on NASA’s BWB methodology
Fuel weight of LDW-200 was calculated together with Fuel weight of LDW-200 was calculated together with the total drag ratio between LDW-200 and B767-the total drag ratio between LDW-200 and B767-300ER aircraft to satisfy the condition related to 300ER aircraft to satisfy the condition related to identical range of both aircraftidentical range of both aircraft
Weight calculations for both aircraft was performed Weight calculations for both aircraft was performed for mid-cruise conditionsfor mid-cruise conditions
Aug 13, 2013 23Longitudinal Double Wing (LDW) Aircraft
Calculation Methodology Calculation Methodology …cont.…cont.
Pitch control efficiency was calculated as being Pitch control efficiency was calculated as being directly proportional to pitch momentum and directly proportional to pitch momentum and inversely proportional to aerodynamic and mass inversely proportional to aerodynamic and mass inertia of aircraft. Aerodynamic inertia is inertia of aircraft. Aerodynamic inertia is directly proportional to aerodynamic surface directly proportional to aerodynamic surface area and length of mean aerodynamic chord.area and length of mean aerodynamic chord.
Roll control efficiency was calculated as directly Roll control efficiency was calculated as directly
proportional to roll momentum and indirectly proportional to roll momentum and indirectly
proportional to aerodynamic and mass inertia.proportional to aerodynamic and mass inertia.
Aug 13, 2013 24Longitudinal Double Wing (LDW) Aircraft
Calculation Methodology Calculation Methodology …cont.…cont.
Steps to calculate LDW-200 fuel weightSteps to calculate LDW-200 fuel weight::
Gf(LDW) = (Fd(LDW)/Fd(B767)) x Gf(B767) (1)
Assuming that the total drag distribution of B767 is the same as roughly a general drag distribution for Assuming that the total drag distribution of B767 is the same as roughly a general drag distribution for commercial TAW aircraft commercial TAW aircraft
where Induced Drag = 40%, Compression Drag = 40%, and Parasitic Friction Drag = 20% of the total drag where Induced Drag = 40%, Compression Drag = 40%, and Parasitic Friction Drag = 20% of the total drag then then
Fd(LDW)/Fd(B767) = 0.4 x (Fdi(LDW)/Fdi(B767)) + 0.4 x (Fdc(LDW)/Fdc(B767)) + 0.2 x Fdp(LDW)/Fdp(LDW) (const.) (2)
where Fdi = ki x f(G²); Fdc = kc x f(G); Fdp = kf x Cdf x Aw = kpf; ki, kc, kpf = f(geometry) for both aircraft
For example, for Inviscid Induced Drag ki = f(e, AR, Aw)
Example of quadratic function of weight FDi = q x Cdi x Aw CL = Gmid/(qAw)CDi = CL²/eπAR CL² = Gmid²/(q²Aw²) FDi = q x (CL²/eπAR) x Aw FDi = [1/(qπ)] x [Gmid²/(eAR Aw)] = f(G²)
where 1/e AR Aw is ki geometry factor for each aircraft. Therefore formula (2) becomes
Fd(LDW)/Fd(B767) = 0.4 x Ki x G²(LDW)/G²(B767) + 0.4 x Kc x G(LDW)/G(B767) + 0.2 x Kpf (3)
where Ki = ki(LDW)/ki(B767); Kc = kc(LDW)/kc(B767); Kpf = kpf(LDW)/kpf(B767)
Since G(LDW) = Goe + Gp + Gf (operating weight empty + payload + fuel) then
G(LDW) = Goe(LDW)+Gp(LDW) + (Fd(LDW)/Fd(B767)) x Gf(B767) (4)
Formulas (3) and (4) are used in iterative process until Formulas (3) and (4) are used in iterative process until G(LDW) from the current iteration is very close to the from the current iteration is very close to the one in the prior iteration.one in the prior iteration.
Aug 13, 2013 25Longitudinal Double Wing (LDW) Aircraft
ResultsResults
Weight
FlightControl
Efficiency
Specific Fuel
Consumption
Categories
Viscous Induced Drag was not Viscous Induced Drag was not taken into consideration though taken into consideration though logically LDW has lower valueslogically LDW has lower values
Interference Drag was not Interference Drag was not estimated due to low impact for estimated due to low impact for both types of aircraftboth types of aircraft
Wave Drag was not estimated due Wave Drag was not estimated due to relatively minor impact at to relatively minor impact at speeds at or under Mach 0.8 speeds at or under Mach 0.8 though LDW is having clear though LDW is having clear advantages due to lower airfoil advantages due to lower airfoil thicknessthickness
ParasiticFriction
Drag
InducedDrag
Compression Drag
RollContr
ol
PitchContr
ol
TotalDrag
Yaw Control was not Yaw Control was not considered here as not considered here as not critical for LDW-200 due critical for LDW-200 due to engines being grouped to engines being grouped around symmetry axisaround symmetry axis
Aug 13, 2013 26Longitudinal Double Wing (LDW) Aircraft
Results - WeightResults - Weight
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
LDW-200 vs. B767 [%](Positives and Negatives)
Diff [%] 31.04% 19.98% 56.72% 55.97% 35.54% 30.34%
Operating Empty
Max. Payload
Max. FuelMid-cruise
FuelMax. Take-
offMid-cruise
Aug 13, 2013 27Longitudinal Double Wing (LDW) Aircraft
Results – Induced Drag Results – Induced Drag (Inviscid)(Inviscid)
-50.00%
0.00%
50.00%
100.00%
150.00%
200.00%
LDW-200 vs. B767 [%] (Positives and Negatives)
Diff [%] 30.34% 172.96% -12.36% -48.10%
Gmid Area (Aw )Osw ald's Factor (e)
Aspect Ratio (AR)
FDi = q x CDi x Aw; Due to CDi = CL²/eπAR FDi = q x (CL²/eπAR) x AwCL = Gmid/(qAw); CL² = Gmid²/(q²Aw²), thusFDi = [1/(qπ)] x [Gmid²/(eAR Aw)]
Aug 13, 2013 28Longitudinal Double Wing (LDW) Aircraft
Results – Compression Results – Compression DragDrag
0%
5%
10%
15%
20%
25%
30%
35%
LDW-200 vs. B767 [%](Positives and Negatives)
Diff [%] 9% 30% 22%
(1/ℓMGC)^0.11 Gmid t/c
Aug 13, 2013 29Longitudinal Double Wing (LDW) Aircraft
Results – Parasitic Results – Parasitic Friction DragFriction Drag
-20.00%
-10.00%
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
70.00%
LDW-200 vs. B767 [%](Positives and Negatives)
Diff [%] -11.00% 61.16% 56.89%
Kf x Cdf Ap Fdp = Kf x Cdf x Ap
Aug 13, 2013 30Longitudinal Double Wing (LDW) Aircraft
Results – Specific Fuel Results – Specific Fuel ConsumptionConsumption
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
70.00%
LDW-200 vs. B767 [%](Positives and Negatives)
Diff [%] 56.73% 19.98% 63.93%
Total Drag PayloadSFC =
(FD(LDW)/FD(B767))
Aug 13, 2013 31Longitudinal Double Wing (LDW) Aircraft
Results – Pitch ControlResults – Pitch ControlApcs area of pitch control surfaces Afas area of front airlifting surfacesPA pitch armℓMGC the length of mean geometric chord of front airlifting surface
(replaced mean aerodynamic chord due to CL = const.)
-150.00%
-100.00%
-50.00%
0.00%
50.00%
100.00%
LDW-200 vs. B767 [%](Positives and Negatives)
Diff [%] 74.64% -14.71% 30.34% -146.27%
Apcs/Afas PA Gmid ℓMGC
Aug 13, 2013 32Longitudinal Double Wing (LDW) Aircraft
Results – Roll ControlResults – Roll ControlArcs roll control surface area around aileronsLrcs distance of resultant aerodynamic force
of Roll Control SurfacesAelv surface area around elevonsLelv distance of resultant aerodynamic force
of elevons from G.C.Aw wing areabMGC(w) distance of wing M.G.C. from G.C.AHT surface area of horizontal tailbMGC(ht) distance of horizontal tail M.G.C. from G.C.Gmid mid-cruise aircraft weight
-100.00%
-50.00%
0.00%
50.00%
100.00%
150.00%
LDW-200 vs. B767 [%](Positives and Negatives)
Diff [%] 105.82% -86.87% 30.34%
[(Arcs x Lrcs) + (Aelv x Lelv)
Aw x bMGC(w ) + AHT x bMGC(ht)
Gmid
Aug 13, 2013 33Longitudinal Double Wing (LDW) Aircraft
ConclusionConclusion Significantly lower operating empty weight of LDW by Significantly lower operating empty weight of LDW by
over 30% relative to TAW aircraft due to overall over 30% relative to TAW aircraft due to overall architecture and broad application of composite architecture and broad application of composite materialsmaterials
Significantly reduced total drag of LDW (>50%) at Significantly reduced total drag of LDW (>50%) at high subsonic speeds due to drastically lower lift high subsonic speeds due to drastically lower lift coefficient that depends on specific wing loading, coefficient that depends on specific wing loading, significantly lower airfoil relative thickness that significantly lower airfoil relative thickness that depends on chord lengths and wing specific loading, depends on chord lengths and wing specific loading, as well as significantly lower total parasitic wetted as well as significantly lower total parasitic wetted area with long chords and low airfoil relative area with long chords and low airfoil relative thicknessthickness
Significantly reduced specific fuel consumption of Significantly reduced specific fuel consumption of LDW aircraft (> 60%) due to overall drag reduction LDW aircraft (> 60%) due to overall drag reduction and additional payload accommodationand additional payload accommodation
Roughly the same levels of flight controlsRoughly the same levels of flight controls Significantly reduced cabin and environmental noise Significantly reduced cabin and environmental noise
levels of LDW aircraft due to longer distance of levels of LDW aircraft due to longer distance of engines from passenger cabin and upward deflection engines from passenger cabin and upward deflection of engine pitch trim surfaces respectivelyof engine pitch trim surfaces respectively