Blended wing and multiple-body airplane configuration

Abstract: The invention relates to a partial blended wing body airplane configuration combining the advantages of a pure blended wing configuration with the advantages of conventional aircraft design. In a blended tri-body airplane configuration three pressurized body elements (10,12,14) are connected by and blended with a pressurized centerwing (20) element. The sidebodies (10,14) and centerbody (12) are blended into the wing structure, producing a multi-body airplane whose body sections are interconnected utilizing wing payload carrying sections.

Description: The present invention relates to multiple-body aircraft and more particularly to a blended tri-body airplane configuration as defined in the preamble of claim 1. Such an airplane configuration is known from GB-A-1 209 290. This prior art document discloses a tri-body airplane configuration including parts of two Boeing 747 aircraft forming left and right sidebodies that are connected by a specially designed center wing. Each Boeing 747 retains one of its original two wings, which forms an outer wing of the tri-body airplane. In one embodiment, shown in Fig. 1 of this prior art document, each Boeing 747 retains most of its tail structure, these tails being joined by a common tailplane. In this embodiment the center wing carries a blended centerbody fuselage extending forward of the two Boeing 747 sidebodies. In another embodiment, shown in Fig. 7, the prior art document proposes to use a third Boeing 747 fuselage as centerbody fuselage. This centerbody fuselage is arranged forward of the two sidebody fuselages and the center wing has conventional rearward sweep. The tail structures of the three Boeing 747 aircraft are retained and again joined by a common tailplane. US-A-3,869,102 is illustrative of a cargo aircraft having a non-pressurized hull which can comprise a number of substantially identical hull modules defining a rectangular cargo area. The hull is shaped as an airfoil and generates lift to substantially offset the combined weight of the hull and payload carried therein. The hull supports outboard wings on both sides, a tail structure and engines. A pressurized cabin is attached to the center of the hull and extends forward thereof. Finally, US-A-2,224,641 discloses an all-wing airplane having two sidebody fuselages connected by a center wing, each sidebody fuselage carrying an outer wing. Payload is carried both in the fuselages and in the center wing. This prior art document relates to a low-flying propellor airplane, the fuselages and center wing of which are nog pressurized. The airplane has two nose gears and two main gears, all of which are retractable into the non-pressurized center wing. Future large airplanes, in order to be economically successful, should satisfy the following requirements: 1. Provide lower fuel burn per seat mile and lower Total Airplane Related Operating Costs (TAROC) per seat mile relative to current large aircraft viz. the Boeing 747. 2. Maximize cruise Lift to Drag ratio (L/D), to help enable lower fuel burn per seat mile. 3. Provide low wetted area per seat and low Overall Empty Weight (OEW) per seat, to help enable lower fuel burn per seat mile. 4. Provide large cabin volume per wetted area and large volume per wetted area, to maximize profit potential. 5. Provide combination use or "combi" capability to convert some passenger capacity to cargo capacity for some airlines for which revenue cargo is important and for which passenger seat count needs are not as large as for other airlines. 6. Provide a low to modest level of technical risk and certification risk. To this end the present invention provides an improved blended tri-body airplane configuration combining the features defined in claim 1. Preferred embodiments of the airplane configuration of the invention form the subject-matter of the dependent claims. The wing body blending provides reduced wetted area and span loading resulting in reduced OEW (Overall Empty Weight) per seat. Large loads are placed where lift is located. The present invention provides conventional flying qualities without need for critical SAS (Stability Augmentation Systems). Fuel burn reduction results from the hereinafter described three engines with less weight. FIG. 1A is a plan view and FIG. 1B is a rear view of a blended tri-body airplane that does not form part of the present invention; FIG. 2A is a plan view and FIG 2B is a rear view of a door arrangement and evacuation slide arrangement for the blended tri-body airplane configuration shown in FIG. 1A and FIG. 1B; FIG. 3A is a plan view and FIG. 3B is a rear view of a dual-body configuration which is a variant of the airplane of FIG. 1A and FIG. 1B without forebody and which does not form part of the invention either; FIG. 4A is a plan view and FIG. 4B is a rear view of a second blended tri-body airplane differing from the embodiment of FIG. 1A and FIG. 1B comprising a single deck forebody and having double deck sidebodies but not forming part of the invention; FIGS. 5A, 5B and 5C and further FIGS. 6B and 6C show plan views which are further illustrative of further embodiments of blended tri-body airplanes that do not form part of the invention; FIG. 6A is a plan view of a first embodiment of a blended tri-body airplane in accordance with the present invention; FIGS. 7A, 7B and 7C illustrate plan views of "combi" compartments which may be utilized in the hereinbefore described blended wing multi-body airplanes not forming part of the invention; FIGS. 8A, 8B, 8C and 8DC illustrate plan, front, side and isometric views of yet another preferred embodiment of the invention; and FIG. 9 illustrates a typical cabin interior arrangement for the embodiment show in FIG. 8. Figure 1A is a plan view and Figure 1B is a rear view of a blended tri-body airplane that does not form part of the invention. This configuration features three pressurized body elements 10, 12, and 14 connected by and blended with a pressurized centerwing element 20 which also carries payload (e.g. passengers). In the forward body element comprising forebody 12 is a doubledeck body capable of providing two stacked passenger seating cabins, similar to the forward body of a Boeing Company model 747-400. Dual sidebodies 10 and 14 are single deck bodies similar to the body of Boeing Company model 777. An additional cargo carrying deck is provided in the lower lobe or lower deck areas beneath the passenger seating cabins in both forebody 12 and sidebodies 10 and 14. In alternative embodiments forebody 12 may include a single deck suitable for accommodating passengers instead of a double deck, and/or sidebodies 10 and 14 may have double decks suitable for accommodating passengers instead of single decks for that purpose. Also further embodiments may feature forebodies and sidebodies of various cross-sectional shapes and sizes, with passenger deck sizes ranging from 2 abreast to 20 abreast. In the embodiment of Figure 1, outerwings 18 and 20 are provided outboard of sidebodies 10 and 14. Outerwings 18 and 20 comprise state of the art airplane wings and may be high, mid, or low wings (high wings are shown for purposes of illustration). Outerwings 18 and 20 will typically operate at considerably higher lift coefficients than centerwing 20, but the spanwise distribution can still remain quite smooth since centerwing 20 has considerably more chord than outerwings 18 and 20. Aerodynamic fairing treatment provides aerodynamic smoothing from the outerwing flow region across the sidebody to the centerwing flow region. Winglets 30 and 32 or other wingtip aerodynamic induced drag reducing treatments may be provided at the outer ends of outer ends of outerwings 18 and 20 as shown. The embodiment shown has a preferred overall span S of around 261 ft., just under the 80 meter limit specified for the ICAO Code F airplane size category. An overall length L well under 80 meters is shown in Figure 1, and "stretch" body versions may be utilized with increased payload (passenger and cargo) capacity which still fall within an 80 meter or 85 meter length limit. Such stretch body versions are provided by adding constant section fuselage plugs into forebody 12 just ahead of centerwing 20, and to sidebodies 10 and 14 just behind centerwing 20. The blended tri-body airplane of Figures 1A and 1B may utilize fabrication materials such as metal, composite, or other materials or combinations of materials. Benefits may be achieved through utilization of stitched RFI composite structure for centerwing 20. The airplane of Figures 1A and 1B is shown with "T-tail" empennage installations 50 and 54 above the aft ends of sidebodies 10 and 14 for contributing to airplane stability and control (trimmable stabilizer, elevator, and rudder means may be provided for trim and control purposes). Further variations may feature low tails, V-tails, and H-tail or inverted V-tail or other tail configurations connecting between sidebodies 10 and 14 or other tail configurations. The airplane of Figure 1A and Figure 1B show a nose landing gear 60 which can retract into forebody 12, and main landing gear 62 which can retract into an unpressurized portion of centerwing 20 behind the pressurized portion. A 4-wheel single post nose gear and a 20-wheel, four post main gear are shown for purposes of illustration although other types of wheel and post gear arrangements can be utilized. The airplane configuration of Figure 1A and 1B provides the dual benefits of low drag per seat (due to low wetted area per seat to reduce parasite drag and a large overall span to reduce induced drag) and low OEW per seat (due to low wetted area per seat and due to span load distribution of payloads in addition to engines and fuel). Figure 2A is a plan view of a door and slide arrangement for the Airplane of Figure 1A. The arrangement shown utilizes 8 pairs of type A doors (4 on each side) with slides or slide-rafts 104, and optionally one underbody slide 102 (or alternatively one underbody stairway). Assuming a limit of 110 passengers per pair of type A doors, the door exit limit capacity of this configuration should be 935 (or 880 even if no credit is taken for the underbody slide). The illustrated door arrangement is intended to meet the 60 ft. maximum longitudinal separation between door edges rule, and to enable safe evacuation of passengers from the airplane in the required 90 seconds. Alternate door arrangements and escape slide arrangements are possible. Figure 3A is a plan view and Figure 3B is a rear view of the aircraft of Figure 1A and 1B but without a forebody however retaining the aforementioned advantages of a blended wing mutiple-body airplane. A cockpit 200 is located in or near the forward apex of centerwing 20 or in the alternative in or near the forward end of a sidebody 10 or 14. Figure 4A is a plan view and Figure 4B is a rear view of a second blended tri-body configuration that does not form part of the invention either. This configuration differs from the configuration of Figures 1A and 1B in several aspects including utilization of a single deck forebody 200 and aft double deck sidebodies 202 and 204. Figures 5A, 5B and 5C and further Figures 6B and 6C show plan views of features which are variants of the hereinbefore described blended wing multi-body airplanes and which do not form part of the invention either, including: swept-forward outerwings; centerwing with swept-aft leading edge and swept-forward trailing edge; and various tail/empennage configurations, including T-tails, split V-tails or low tails, an H-tail or inverted V-tail or further tail configurations (not shown) connecting between the two sidebodies. Figure 6A shows a plan view of a first embodiment of a blended tri-body airplane in accordance with the present invention, including the following features: swept-forward centerwing; aftbody instead of forebody on the airplane centerline (i.e. centerbody behind instead of ahead of sidebodies); extended body lengths; several engines exceeding two; and a tail/empennage attached to the aftbody. Figures 7A, 7B and 7C are illustrative of plan views of "combi" compartments which may be utilized on a blended wing multi-body airplane configuration, which compartments are suitable for carrying cargo in pallets e.g. 201 and 202 or which airplane may be converted back to passenger carrying configurations. In the preferred embodiment of the blended tri-body airplane of the invention shown in Figure 8, sidebodies 10 and 14 are forward of and along the length of centerwing 20. Centerwing 20 has forward swept leading and trailing edges. Variations of the centerwing 20 sweep are forward swept leading edge with aft swept trailing edge, aft swept leading edge with forward swept trailing edge and aft swept leading and trailing edges. The cockpit is located in the forward section of one of the sidebodies 10 and 14. Center engine 41a is shown mounted center and forward of centerwing 20 on a pylon. An alternative installation of center engine 41a is in the vertical tail structure similar to a McDonnell Douglas DC 10. Aft body 12a is connected to centerwing 20 and extends aft to support the empennage. The interior of aft body 12a is connected to the pressurized section of centerwing 20 allowing the free movement of passengers. The cross section of 12a may consist of a single passenger deck with lower cargo deck or may consist of double passenger decks with lower cargo deck similar to a Boeing 747. Nose landing gears 60a are shown in an unpressurized bay in each of sidebodies 10 and 14. Main landing gear 62 are attached to the structure of centerwing 20 and retract into unpressurized gear bays at the rear of centerwing 20. While certain preferred embodiments of the invention have been described with reference to the attached figures, it should be understood that further variations and modifications are possible within the scope of the invention as defined in the claims below.

Claims: A blended tri-body airplane configuration comprising in combination: (i) a centerbody fuselage (12a) capable of carrying payload in a pressurized volume thereof, (ii) a tail surface mans (51) attached to the aft part of the airplane, for controlling the airplane in the pitch and yaw axes, (iii) a center wing (20) attached to the centerbody fuselage (12a), which center wing (20) is capable of generating aerodynamic lift and of carrying payload in a pressurized volume thereof, (iv) a left sidebody fuselage (10) attached to the left end region of said center wing (20) and capable of carrying payload in a pressurized volume thereof, (v) a right sidebody fuselage (14) attached to the right end region of said center wing (20) and capable of carrying payload in a pressurized volume thereof, wherein the pressurized volumes of the left sidebody, centerbody and right sidebody fuselages (10, 12a, 14) and of the center wing (20) are fluidly connected so that payload may be moved between the volumes without passing through any unpressurized portions of the aircraft, characterized in that the center wing (20) is a forward-swept wing having an aft apex region, the centerbody fuselage (12a) is an aft centerbody fuselage having a forward end attached to the aft opex region of the forward-swept center wing (20), and the tail surface means (51) is attached to the aft part of the aft centerbody fuselage (12a) only. The airplane configuration of claim 1, characterized in that the tail surface mans (51) comprises a T-tail. The airplane configuration of claim 1 or 2, characterized by left and right outer wings (18, 19) attached respectively to the outboard sides of said left and right sidebody fuselages (10, 14). The airplane configuration of claim 3, characterized in that said two outer wings (18, 19) have higher lift coefficients than said center wing (20) and said center wing (20) has more chord than said two outer wings (18, 19). The airplane configuration of claims 3 or 4, characterized by at least two engines (40, 42) attached by strut means to the left and right outer wings (18, 19) at positions outboard of the left and right sidebody fuselages (10, 14). The airplane configuration of any of the preceding claims, characterized by an engine (41a) attached by strut means to the forward end of the center wing (20). The airplane configuration of any of claims 1 to 5, characterized by an engine (41a) installed in a vertical section of the tail surface means (51). The airplane configuration of any of the preceding claims, characterized in that said aft centerbody fuselage (12a) and/or both said left and right sidebody fuselages include(s) two stacked passenger accommodating decks. The airplane configuration of any of the preceding claims, characterized in that said center wing (20) is aerodynamically and structurally blended with said left and right sidebody fuselages (10,14) and/or said centerbody fuselage (12a). The airplane configuration of any of the preceding claims, characterized by a cockpit located in the forward section of one of the sidebody fuselages (10, 14). The airplane configuration of any of the preceding claims, characterized by nose landing gears (60a) and main landing gears (62) each including wheels and tires, each said nose landing gear (60a) being retractable into an unpressurized bay in one of said sidebody fuselages (10, 14) and said main landing gears (62) each being retractable into an unpressurized aft portion of said center wing (20).

Inventors: SANKRITHI MITHRA M K V, WALD STEVEN J, SANKRITHI, MITHRA M.K.V., WALD, STEVEN J.
Applicants: BOEING CO, THE BOEING COMPANY
Application year: 2001
Main classification: B64C39
IPC codes: B64C39