Aerodynamic considerations of blended wing body aircraft

Qin, Ning; Vavalle, Armando; Moigne, Alan Le; Laban, M.; Hackett, K.; Weinerfelt, Per

doi:10.1016/j.paerosci.2004.08.001

Cited by 192 publications

(125 citation statements)

References 28 publications

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“…In Figure 15(a), the lift distribution of the planform-optimized configuration (red line) is compared to the previous ones: the trend resembles an averaged elliptical/triangular distribution, which provides the best aerodynamic trade off, as proved by Qin et al 15,16 This is mainly obtained by sweeping the outboard wing further back to 33.8 • , reducing the taper ratio from 0.15 to 0.13 and increasing the nose-down wash out (Table 6). This last modification is responsible for the decrease in local lift coefficient over the outboard wing, as displayed in Figure 15(b).…”

Section: Su2 Euler Planform Optimization: From Config 1 To Configmentioning

confidence: 69%

Aerodynamic Design of a Flying V Aircraft

Faggiano

Vos

Baan³

et al. 2017

17th AIAA Aviation Technology, Integration, and Operations Conference

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A Flying V aircraft is a tailless, V-shaped flying wing with two cylindrical pressurized cabins placed in the wing leading edge and two over-the-wing engines. Elevons provide longitudinal and lateral control while two tip-mounted vertical tails double as winglets. The goal of the presented study is to estimate the lift-to-drag ratio of this configuration at the cruise condition: M = 0.85, h = 13, 000m, and CL = 0.26. A vortex-lattice method is used to rapidly investigate the feasible design space, whereas an Euler solver on an unstructured grid is adopted for a more accurate wave and vortex-induced drag estimation. The profile drag is computed by an empirical method. The NASA Common Research Model is adopted as a benchmark with an estimated lift-to-drag ratio of 18.9. The three-dimensional geometry of the Flying V is generated according to a multi-level parametrization: the planform shape is parametrized with 10 variables, five wing sections are identified and described by a total of 43 parameters, while the winglet planform is defined by 3 additional variables. After a multi-fidelity design space exploration, two design approaches are investigated: a dual-step optimization, where planform and airfoil variables are subsequently varied, and a single-step optimization, where planform and airfoil variables are varied simultaneously. The highest lift-to-drag ratio is attained with the single-step optimized configuration and amounts to 23.7. It is therefore concluded that the Flying V Aircraft can have a 25% higher lift-to-drag ratio than the reference aircraft.

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Section: Su2 Euler Planform Optimization: From Config 1 To Configmentioning

confidence: 69%

Aerodynamic Design of a Flying V Aircraft

Faggiano

Vos

Baan³

et al. 2017

17th AIAA Aviation Technology, Integration, and Operations Conference

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“…The maximum camber location has a strong in §uence on the pitching moment and a slight e¨ect on drag polar; so, it can be used to compensate for the lift reduction resulting from the use of a re §exed aerofoil section. The spanwise twist distribution does not give enough help in terms of stability with these types of aerofoil section [14,15]; selecting a suitable combination of sweep and twist distribution to generate zero pitching moment (with a slightly-re §exed aerofoil section) [16,17]; using a suitable dihedral angle (or dihedral distribution) could add some enhancement in the lateral direction [18]; and using winglets or C-wings to reduce induced drag and add further directional stability and control [19,20].…”

Section: Stability Of Flying-wing Aircraftmentioning

confidence: 99%

Design of a high altitude long endurance flying-wing solar-powered unmanned air vehicle

Alsahlani

Johnston

Atcliffe

2017

Progress in Flight Physics

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The low-Reynolds number environment of high-altitude §ight places severe demands on the aerodynamic design and stability and control of a high altitude, long endurance (HALE) unmanned air vehicle (UAV). The aerodynamic e©ciency of a §ying-wing con¦guration makes it an attractive design option for such an application and is investigated in the present work. The proposed con¦guration has a high-aspect ratio, swept-wing planform, the wing sweep being necessary to provide an adequate moment arm for outboard longitudinal and lateral control surfaces. A design optimization framework is developed under a MATLAB environment, combining aerodynamic, structural, and stability analysis. Low-order analysis tools are employed to facilitate e©cient computations, which is important when there are multiple optimization loops for the various engineering analyses. In particular, a vortex-lattice method is used to compute the wing planform aerodynamics, coupled to a twodimensional (2D) panel method to derive aerofoil sectional characteristics. Integral boundary-layer methods are coupled to the panel method in order to predict §ow separation boundaries during the design iterations. A quasi-analytical method is adapted for application to §ying-wing con¦gurations to predict the wing weight and a linear ¦nite-beam element approach is used for structural analysis of the wing-box. Stability is a particular concern in the low-density environment of high-altitude §ight for §ying-wing aircraft and so provision of adequate directional stability and control power forms part of the optimization process. At present, a modi¦ed Genetic Algorithm is used in all of the optimization loops. Each of the low-order engineering analysis tools is validated using higher-order methods to provide con¦dence in the use of these computationally-e©cient tools in the present design-optimization framework. This paper includes the results of employing the present optimization tools in the design of a HALE, §ying-wing UAV to indicate that this is a viable design con¦guration option.

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“…The aircraft is balanced by downloading the rear of the centerbody (via reflex camber), where the centerbody now acts like a tail. Other BWB designs (for example, Qin et al [3]) have also achieved longitudinal stability using this design feature. To help balance the aircraft, the lift distribution of the Liebeck [2] aircraft is triangular.…”

Section: B Stability Of the Blended-wing Bodymentioning

confidence: 99%

“…In addition to providing a step change in noise emissions, the conceptual aircraft design is predicted to be aerodynamically efficient, with a fuel economy that is potentially 25% better than current aircraft designs (Hileman et al [1]) Although the blended-wing-body (BWB) planform used in the SAX-40 may look similar to past BWB designs (including Liebeck [2] and Qin et al [3]), the use of leading-edge carving in the design allows the entire planform to generate lift, and the final aircraft is both balanced and statically stable. This paper decomposes the aerodynamic forces into contributions from spanwise sections to explain how centerbody leading-edge carving can be used to create an efficient and stable BWB-type aircraft design.…”

mentioning

confidence: 99%

Stability of Hybrid-Wing-Body-Type Aircraft with Centerbody Leading-Edge Carving

Sargeant¹,

Hynes²,

Hileman³

et al. 2010

Journal of Aircraft

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The silent-aircraft experimental aircraft are balanced by generating lift near the aircraft nose through leadingedge carving of the centerbody. The use of leading-edge carving over the centerbody is novel, in that previous blended-wing-body aircraft have balanced the aircraft by downloading the centerbody (via reflex camber) to achieve the effect of a tail. This paper decomposes the aerodynamic forces into contributions from spanwise sections to explain how three-dimensional flow effects are beneficial in allowing the silent-aircraft experimental aircraft to be both statically stable and to have an elliptical lift distribution over a large range of angles of attack. By analyzing the results in this manner, rationale is also given as to why, unlike other blended-wing-body-type configurations, the silent-aircraft-experimental design can use supercritical unstable-outer-wing airfoil profiles to generate a balanced and stable aircraft. The results are then used to develop a methodology to aid the aircraft designer in determining the amount of leading-edge carving that is necessary to achieve static stability for blended-wing-body-type aircraft.

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Aerodynamic considerations of blended wing body aircraft

Cited by 192 publications

References 28 publications

Aerodynamic Design of a Flying V Aircraft

Aerodynamic Design of a Flying V Aircraft

Design of a high altitude long endurance flying-wing solar-powered unmanned air vehicle

Stability of Hybrid-Wing-Body-Type Aircraft with Centerbody Leading-Edge Carving

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