1. Longitudinal Double Wing (LDW) Concept Presented by Michael Dizdarevic AIAA Aviation 2013 Conference - Los Angeles

2. Aug 13, 20132Longitudinal Double Wing (LDW) Aircraft Agenda About the research team About the research team Introduction of LDW concept Introduction of LDW concept General aircraft classification and characteristics General aircraft classification and characteristics LDW configuration and characteristics LDW configuration and characteristics Similarities and differences between LDW and tube-and-wing (TAW) aircraft Similarities and differences between LDW and tube-and-wing (TAW) aircraft Architectural impact on aircraft performance Architectural impact on aircraft performance Case study (LDW-200 vs. B767-300ER) Case study (LDW-200 vs. B767-300ER) Assumptions and Methodology Assumptions and Methodology Results Results Conclusion Conclusion Q & A Q & A

3. Aug 13, 20133Longitudinal Double Wing (LDW) Aircraft About Research Team FARUK DIZDAREVIC (Principal Researcher) VP R&D Soko Aircraft Industry – the largest aircraft company in former Yugoslavia. VP R&D Soko Aircraft Industry – the largest aircraft company in former Yugoslavia. Previously a head of company’s Aircraft and Helicopter divisions involving manufacturing of their own military training and combat aircraft, as well as various components for World’s major aircraft including B737/757, MD-80, and A310/330/340, etc. Previously a head of company’s Aircraft and Helicopter divisions involving manufacturing of their own military training and combat aircraft, as well as various components for World’s major aircraft including B737/757, MD-80, and A310/330/340, etc. University professor in the area of aircraft manufacturing technologies for many years. University professor in the area of aircraft manufacturing technologies for many years. Extensive experience and expertise related to the research of Flying Wing aerodynamic concepts for the past 20+ years. Extensive experience and expertise related to the research of Flying 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.

4. Aug 13, 20134Longitudinal Double Wing (LDW) Aircraft About Research Team …cont. MICHAEL DIZDAREVIC (Researcher ) Research of Flying Wing aerodynamic concepts for the past 20+ years. Research of Flying Wing aerodynamic concepts for the past 20+ years. Versatile University level educational background in Mechanical and Aeronautical Engineering, as well as Finance and Computer Science. Versatile University level educational background in Mechanical and Aeronautical Engineering, as well as Finance and Computer Science. Extensive work experience with large scale data processing, integration, modeling, and analysis with major US and international corporations including project management for the past 15 years. Extensive work experience with large scale data processing, integration, modeling, and analysis with major US and international corporations including project management for the past 15 years.

5. Aug 13, 20135Longitudinal Double Wing (LDW) Aircraft General Aircraft Classification 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 Aircraft Tailless Flying Wing (TFW) Aircraft Goals

6. Aug 13, 20136Longitudinal Double Wing (LDW) Aircraft LDW Aerodynamic Concept Visualization

7. Aug 13, 20137Longitudinal Double Wing (LDW) Aircraft LDW Configuration Front Wing Architectural Configuration V-tailRear Wing

8. Aug 13, 20138Longitudinal Double Wing (LDW) Aircraft Aircraft Characteristics Accommodation of 90% of installations, instruments, and equipment Landing Gear Accommodation Roll control of aircraft in all flight configurations Fuel Disposal Production of extra lift needed at low speed during take-off and landing Payload Disposal Production of 80% of necessary lift in cruising flight configuration Cockpit Aerodynamics Front Wing (FW) Architecture

9. Aug 13, 20139Longitudinal Double Wing (LDW) Aircraft Aircraft Characteristics …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

10. Aug 13, 201310Longitudinal Double Wing (LDW) Aircraft Aircraft Characteristics …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

11. Aug 13, 201311Longitudinal Double Wing (LDW) Aircraft LDW and TAW Similarities Both aircraft having pronounced separate front and rear aerodynamic surfaces for lift production and reliable flight controls Both aircraft having pronounced separate front and rear aerodynamic surfaces for lift production and reliable flight controls The ratio between rear and front aerodynamic surfaces is rather close at around 0.5 for both aircraft The ratio between rear and front aerodynamic surfaces is rather close at around 0.5 for both aircraft Span and overall length of both aircraft for a given aircraft category are rather close Span and overall length of both aircraft for a given aircraft category are rather close Resulting similar flight control efficiency Resulting similar flight control efficiency

12. Aug 13, 201312Longitudinal Double Wing (LDW) Aircraft LDW and TAW Differences Different shape, size, architecture, and aerodynamic tasks of connecting bodies (V-tail and fuselage respectively) Different shape, size, architecture, and aerodynamic tasks of connecting bodies (V-tail and fuselage respectively) Different inner shape, payload distribution, and structural integration with other sections, as well as different aerodynamic function of payload bay. Different inner shape, payload distribution, and structural integration with other sections, as well as different aerodynamic function of payload bay.

13. Aug 13, 201313Longitudinal Double Wing (LDW) Aircraft LDW and TAW Differences …cont. Different design and position of engines’ aerodynamic cover, as well as integration with other aircraft sections Different design and position of engines’ aerodynamic cover, as well as integration with other aircraft sections Different size and flight mechanics task of rear aerodynamic surfaces Different size and flight mechanics task of rear aerodynamic surfaces Different size of front aerodynamic surfaces for the same class aircraft Different size of front aerodynamic surfaces for the same class aircraft

14. Aug 13, 201314Longitudinal Double Wing (LDW) Aircraft Architecture Performance Impact

15. Aug 13, 201315Longitudinal Double Wing (LDW) Aircraft Architecture Performance Impact

16. Aug 13, 201316Longitudinal Double Wing (LDW) Aircraft Architecture Performance Impact

17. Aug 13, 201317Longitudinal Double Wing (LDW) Aircraft Architecture Performance Impact

18. Aug 13, 201318Longitudinal Double Wing (LDW) Aircraft Architecture Performance Impact

19. Aug 13, 201319Longitudinal Double Wing (LDW) Aircraft Case study (LDW-200 vs. B767) Dimensional analysis was performed to identify the separate impact of each architectural element on aircraft performance Dimensional analysis was performed to identify the separate impact of each architectural element on aircraft performance Comparison case study was performed for B767-300ER long-range version and the equivalent virtual LDW-200 aircraft with similar exploitation characteristics Comparison case study was performed for B767-300ER long-range version and the equivalent virtual LDW-200 aircraft with similar exploitation characteristics

20. Aug 13, 201320Longitudinal Double Wing (LDW) Aircraft Assumptions and Methodology Assumptions Operating Weight Empty Calculations Flight Control Efficiency Ratio Calculation Longitudinal Double Wing (LDW) Aircraft Fuel Weight and Drag Ratio Calculations Specific Fuel Consumption Ratio Calculation Calculation Methodology

21. Aug 13, 201321Longitudinal Double Wing (LDW) Aircraft Assumptions Both aircraft flying at the same speed and altitude Both aircraft flying at the same speed and altitude Same operating range Same operating range Same airfoil family Same airfoil family Constant C L across the span, hence Mean Aerodynamic Chord (M.A.C.) becoming identical to Mean Geometric Chord (M.G.C.) for dimensional analysis purposes Constant C L across the span, hence Mean Aerodynamic Chord (M.A.C.) becoming identical to Mean Geometric Chord (M.G.C.) for dimensional analysis purposes Roughly the same space for payload accommodation Roughly the same space for payload accommodation Same engine efficiency Same engine efficiency

22. Aug 13, 201322Longitudinal Double Wing (LDW) Aircraft Calculation Methodology Fuel weight of B767-300ER aircraft was taken as a difference between Max. T.O. weight and the sum of operating empty weight and Max. payload weight Fuel weight of B767-300ER aircraft was taken as a difference between Max. T.O. weight and the sum of operating empty weight and Max. payload weight Weights of LDW-200 airframe sections were calculated by Stanford University methodology for commercial aircraft and then modified by taking into consideration that 75% of airframe was made of composites except for Cabin and Rear Wing, which were calculated based on NASA’s BWB methodology Weights of LDW-200 airframe sections were calculated by Stanford University methodology for commercial aircraft and then modified by taking into consideration that 75% of airframe was made of composites except for Cabin and Rear Wing, which were calculated based on NASA’s BWB methodology Fuel weight of LDW-200 was calculated together with the total drag ratio between LDW-200 and B767-300ER aircraft to satisfy the condition related to identical range of both aircraft Fuel weight of LDW-200 was calculated together with the total drag ratio between LDW-200 and B767-300ER aircraft to satisfy the condition related to identical range of both aircraft Weight calculations for both aircraft was performed for mid- cruise conditions Weight calculations for both aircraft was performed for mid- cruise conditions

23. Aug 13, 201323Longitudinal Double Wing (LDW) Aircraft Calculation Methodology …cont. Pitch control efficiency was calculated as being directly proportional to pitch momentum and inversely proportional to aerodynamic and mass inertia of aircraft. Aerodynamic inertia is directly proportional to aerodynamic surface area and length of mean aerodynamic chord. Pitch control efficiency was calculated as being directly proportional to pitch momentum and inversely proportional to aerodynamic and mass inertia of aircraft. Aerodynamic inertia is directly proportional to aerodynamic surface area and length of mean aerodynamic chord. Roll control efficiency was calculated as directly proportional to roll momentum and indirectly proportional to aerodynamic and mass inertia. Roll control efficiency was calculated as directly proportional to roll momentum and indirectly proportional to aerodynamic and mass inertia.

24. Aug 13, 201324Longitudinal Double Wing (LDW) Aircraft Calculation Methodology …cont. Steps 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 commercial TAW aircraft where Induced Drag = 40%, Compression Drag = 40%, and Parasitic Friction Drag = 20% of the total drag 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 F Di = q x Cdi x AwC L = Gmid/(qAw) C Di = CL²/eπARC L ² = Gmid²/(q²Aw²) F Di = q x (CL²/eπAR) x AwF Di = [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 from the current iteration is very close to the one in the prior iteration. Formulas (3) and (4) are used in iterative process until G (LDW) from the current iteration is very close to the one in the prior iteration.

25. Aug 13, 201325Longitudinal Double Wing (LDW) Aircraft Results Weight Flight Control Efficiency Specific Fuel Consumption Categories Viscous Induced Drag was not taken into consideration though logically LDW has lower values Viscous Induced Drag was not taken into consideration though logically LDW has lower values Interference Drag was not estimated due to low impact for both types of aircraft Interference Drag was not estimated due to low impact for both types of aircraft Wave Drag was not estimated due to relatively minor impact at speeds at or under Mach 0.8 though LDW is having clear advantages due to lower airfoil thickness Wave Drag was not estimated due to relatively minor impact at speeds at or under Mach 0.8 though LDW is having clear advantages due to lower airfoil thickness Parasitic Friction Drag Induced Drag Compression Drag Roll Control Pitch Control Total Drag Yaw Control was not considered here as not critical for LDW-200 due to engines being grouped around symmetry axis Yaw Control was not considered here as not critical for LDW-200 due to engines being grouped around symmetry axis

26. Aug 13, 201326Longitudinal Double Wing (LDW) Aircraft Results - Weight

27. Aug 13, 201327Longitudinal Double Wing (LDW) Aircraft Results – Induced Drag (Inviscid) F Di = q x C Di x Aw; Due to C Di = CL²/eπAR F Di = q x (C L ²/eπAR) x Aw C L = Gmid/(qAw); C L ² = Gmid²/(q²Aw²), thus F Di = [1/(qπ)] x [Gmid²/(eAR Aw)]

28. Aug 13, 201328Longitudinal Double Wing (LDW) Aircraft Results – Compression Drag

29. Aug 13, 201329Longitudinal Double Wing (LDW) Aircraft Results – Parasitic Friction Drag

30. Aug 13, 201330Longitudinal Double Wing (LDW) Aircraft Results – Specific Fuel Consumption

31. Aug 13, 201331Longitudinal Double Wing (LDW) Aircraft Results – Pitch Control Apcs area of pitch control surfaces Afas area of front airlifting surfaces PApitch arm ℓ MGC the length of mean geometric chord of front airlifting surface (replaced mean aerodynamic chord due to C L = const.)

32. Aug 13, 201332Longitudinal Double Wing (LDW) Aircraft Results – Roll Control Arcsroll control surface area around ailerons Lrcsdistance of resultant aerodynamic force of Roll Control Surfaces Aelvsurface area around elevons Lelvdistance of resultant aerodynamic force of elevons from G.C. Awwing area b MGC(w) distance of wing M.G.C. from G.C. A HT surface area of horizontal tail b MGC(ht) distance of horizontal tail M.G.C. from G.C. Gmidmid-cruise aircraft weight

33. Aug 13, 201333Longitudinal Double Wing (LDW) AircraftConclusion Significantly lower operating empty weight of LDW by over 30% relative to TAW aircraft due to overall architecture and broad application of composite materials Significantly lower operating empty weight of LDW by over 30% relative to TAW aircraft due to overall architecture and broad application of composite materials Significantly reduced total drag of LDW (>50%) at high subsonic speeds due to drastically lower lift coefficient that depends on specific wing loading, significantly lower airfoil relative thickness that depends on chord lengths and wing specific loading, as well as significantly lower total parasitic wetted area with long chords and low airfoil relative thickness Significantly reduced total drag of LDW (>50%) at high subsonic speeds due to drastically lower lift coefficient that depends on specific wing loading, significantly lower airfoil relative thickness that depends on chord lengths and wing specific loading, as well as significantly lower total parasitic wetted area with long chords and low airfoil relative thickness Significantly reduced specific fuel consumption of LDW aircraft (> 60%) due to overall drag reduction and additional payload accommodation Significantly reduced specific fuel consumption of LDW aircraft (> 60%) due to overall drag reduction and additional payload accommodation Roughly the same levels of flight controls Roughly the same levels of flight controls Significantly reduced cabin and environmental noise levels of LDW aircraft due to longer distance of engines from passenger cabin and upward deflection of engine pitch trim surfaces respectively Significantly reduced cabin and environmental noise levels of LDW aircraft due to longer distance of engines from passenger cabin and upward deflection of engine pitch trim surfaces respectively

34. Aug 13, 201334Longitudinal Double Wing (LDW) Aircraft Q & A