Abstract:
The invention is a flying wing aircraft having a forward fuselage; an aft fuselage segment; a propulsion segments adapted to mate to the fuselage segments; a pair of wing segments adapted to mate with the propulsion segments. The invention further includes a center section adapted to fit between the forward and aft fuselage sections; the center section adapted to receive multiple compartment systems.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to the field of aircraft manufacturing and, in particular, to a modular design for an aircraft providing an increase in structural commonality while retaining high performance in a single aircraft to architecture designed for multiple missions. 
     2. Description of Related Art 
     The typical aircraft is designed for a few, relatively common mission, for example, a passenger airliner can be converted into a cargo aircraft by removing the passenger seats and increasing the size of the doors. In fact, they can be converted into military refueling aircraft, but with notable structural changes. Of course different weapons systems can be loaded on the wings of military aircraft. Military bombers can have their bomb bays constructed to convert to multiple different weapons carriage systems (e.g. rotary launcher assemblies or bomb rack assemblies). However, none of these aircraft are designed to accomplish multiple missions through being configured in the production line for traditionally different missions. Flying wing type aircraft are generally characterized as having an integrated central portion (fuselage in conventional aircraft) and wings wherein both produce lift. The aerodynamic efficiency of flying wing aircraft is well established. 
     U.S. Pat. No. 5,975,464 Aircraft With Removable Structural Payload Module by E. Rutan discloses an aircraft design wherein a center portion of the fuselage containing the payload is removable and a larger section can be installed. The aircraft also has provisions for adding wing tip extensions to provide additional lift. However, this concept is not particularly new. Commercial airliners are manufactured such that fuselage sections can be added to increase the number of passengers that can be carried. Typically, this requires larger engines and or an increase in wing length. 
     Furthermore, none of these concepts disclose an aircraft design that is modular and primarily only modifies a portion of the fuselage which carries the payload. In particular, an aircraft design that allows an aircraft to be made into a transport, bomber, or refueling aircraft while maintaining the same external dimensions of the aircraft, and with little effect on overall performance thereof. 
     Thus, it is a primary object of the invention to provide a highly common airframe with modular elements for mobility (including short take-off and landing airlift or in-flight refueling) and attack missions that minimize construction changes within the major structural components 
     It is a further object of the invention to provide a modular designed flying wing type aircraft. 
     SUMMARY OF THE INVENTION 
     The invention is an aircraft that includes a flying wing having a longitudinal axis, vertical axis, and a horizontal axis. The aircraft, as part of the flying wing includes a protruding nose section. A canard is mounted on the nose section. The aircraft&#39;s canard, being generally only needed when taking off and landing, is retractable. The aircraft also includes a plurality of extendable flaps mounted on the trailing edge of the flying wing. 
     The overall design of the flying wing aircraft allows for modular construction. Thus the aircraft includes a forward fuselage; an aft fuselage segment; propulsion segments adapted to mate to the fuselage segments; a pair of wing segments adapted to mate with the propulsion segments. The invention further includes a center section adapted to fit in the aft fuselage section; the center section adapted to receive multiple compartment systems. Typically, the aircraft&#39;s multiple cargo compartment systems include a bomb bay and cargo carrying compartment systems. 
     When the flying wing receives the cargo compartment system, left and right retractable canards are mounted to the forward fuselage section and an air supply system to provide pressurized air from the propulsion system for blowing pressurized air over the canards as well as flaps on the trailing edge of the wing is installed. 
     The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description in connection with the accompanying drawings in which the presently preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for purposes of illustration and description only and are not intended as a definition of the limits of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a planform view of a flying wing type aircraft partially broken away to show the interior thereof. 
         FIG. 2  is a partial cross-sectional view of  FIG. 1 . illustrating the canard actuation system. 
         FIG. 3  is a front view of the aircraft shown in  FIG. 1   
         FIG. 4  is a view of the aircraft shown in  FIG. 1  partially broken away to show the engines. 
         FIG. 5  is a schematic view of the of the system for blowing air over the flaps and canard of the aircraft shown in  FIG. 1   
         FIG. 6  is a cross-sectional view the canard taken along the line  5 - 5  in  FIG. 1  illustrating the airflow about the canard when the canard is blown. 
         FIG. 7  is a cross-sectional view of one of the flaps at the trailing edge of the wing. 
         FIG. 8  is an exploded view of the aircraft illustrating the major subassemblies of the aircraft. 
         FIG. 9  is a partial side cross-sectional view of the aircraft configured as a cargo aircraft/ 
         FIG. 10  is a partial side cross-sectional view the aircraft configured as a refueling aircraft. 
         FIG. 11  is a cross-sectional view along the line  11 - 11  shown in  FIG. 10 . 
         FIG. 12  is a cross sectional view of the aircraft configured as a weapons delivery aircraft. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1-5 , the flying wing aircraft, is generally designated by numeral  10  and has longitudinal axis  11 A, vertical axis  11 B and a horizontal axis  11 C. The aircraft  10  includes a nose end  12 , tail end  13  with an overall length  15 . The right and left inner leading edges  16 A and  16 B extend back from the nose end  12  over a distance  17  at a sweep angle  18 , of between 30 and 80 degrees. The distance  17  is about 40 to 60 percent of the total length  15  of the aircraft. The left and right outer leading edges  16 C and  16 D A have a sweep angle  22 , of between 0 and 80 degrees as measured from a local horizontal. 
     Mounted in proximity to the left and right inner leading edges  16 A and  16 B are right and left canards  24 A and  24 B having Coanda effect airfoil cross-sections (see  FIG. 5 ). The canards  24 A and  24 B have an axis of rotation  25 A and  25 B, respectively and an actuation system  26  that retract the canards to form part of the leading edge  16 A and  16 B or the canards may be retracted onto the wing surface. The actuation system  26  will be subsequently discussed. The canards  24 A and  24 B have a downward angle  28 A or upward angle  28 B of between 0 and 20 degrees (see  FIG. 3 ). 
     The left and right inner trailing edges  30 A and  30 B include inboard trailing edge flaps  32 A and  32 B, while the outer left and right outer trailing edges  34 A and  34 B include outboard trailing edge flaps  36 A and  36 B. External of the outboard flaps  36 A and  36 B are split rudders  38 A and  38 B. Referring particularly to  FIG. 5 , the outer left flap  36 A has a pivot axis  39  and actuator(s)  40 . All the flaps are similar. 
     Again referring to  FIGS. 1-7 , the left and right inner trailing edges  30 A and  30 B extends forward from the tail end  13  over a distance  42 , which is between 15 and 40 percent of the length  15 , at a forward sweep angle  44  of between 0 and 45. The left and right outer trailing edge portions  34 A and  34 B are generally parallel to the left and right outer leading edges  30 A and  30 B, respectively. 
     Mounted within the flying wing are four turbofan engines  46 A,  46 B  46 C and  46 D. However, while four engines are shown, the aircraft could only have other propulsion systems and corresponding quantities. The four engines  46 A- 46 D have inlet ducts  48  and exhaust ducts  49  all on the top surface of the aircraft. The engines  46 A- 46 B have compressor sections  50 A,  50 B,  50 C and  50 D and fan sections  51 A,  51 B,  51 C and  51 D. 
     A pressurized air distribution system, indicated by numeral  52 , is installed in the aircraft  10 . The distribution system  52  is divided into two halves  52 A and  52 B. Distribution system  52 A includes lines  53 A and  53 B coupled to the fan sections  50 A and  50 B of the engines  46 A and  46 B which included pressure regulator shut off valves  54 A and  54 B mounted therein. The lines  53 A and  53 B connect to a distribution duct  55 , which provides high pressure air to ducts  56 A and  56 B and  56 C. 
     At takeoff, the engines are at full power and there is sufficient air at high enough pressure level that only fan air is necessary. However, upon landing, where the engines are at a reduced power setting, additional air from the compressor sections of the engine is provided to maintain pressure levels. Thus coupled to the distribution duct  55  are lines  59 A and  59 B, having control pressure regulator valves  60 A and  60 B mounted therein, which are connected to the compressor section  51 A and  51 A of the engines  46 A and  46 B. Therefore, upon landing, the valves  60 A and  60 B are opened. 
     Duct  56 A connects to the distribution channel  61 A, which distributes air over the left outboard flap  36 A and part of inboard flap  32 A via slot  57  (see  FIG. 6 ). Duct  56 B connects to distribution channel  61 B, which distributes air over the left inboard flap  32 A. Duct  56 C distributes air to distribution channel  61 C via a flow control valve  62  and pivoting connection  64  to left canard  24 A (see  FIG. 5 ) The valve  62  is used to control the airflow over left canard  24 A, which exits slot  63  in the distribution channel  61 C to very the lift produced thereby (see  FIG. 6 ). 
     The distribution system  50 B includes lines  72 A and  72 B coupled to the fan sections  51 C and  51 D of the engines  46 C and  46 D which include pressure regulator shut off valves  73 A and  73 B mounted therein. The lines  72 A and  72 B connect to a distribution duct  74 , which provides high pressure air to ducts  76 A and  76 B and  76 C. 
     As previously stated, at takeoff, the engines are at full power and there is sufficient air at high enough pressure level that only fan air is necessary. However, upon landing, where the engines are at a much reduced power setting, it is necessary to provide additional air from the compressor sections of the engine to maintain pressure levels. Thus coupled to the distribution duct  74  are lines  79 A and  79 B, having control pressure regulator valves  80 A and  80 B mounted therein, which are connected to the compressor section  50 C and  50 D of the engines  46 C and  46 D. Therefore, upon landing, the valves  80 A and  80 B are opened. 
     Duct  76 A connects to distribution channel  81 A, which distributes air over the trailing edge outboard flap  36 B and part of flap  32 B. Duct  76 B connects to distribution channel  81 B, which distributes air over the left inboard flap  32 B. Duct  76 C distributes air to distribution channel  81 C via a flow control valve  82  and pivoting connection  84  to right canard  24 B. The valve  82  is used to control the airflow over right canard  24 B to very the lift produced thereby. 
     Thus at takeoff, the right and left canards  24 A and  24 B are extended. With all engines  46 A- 46 D at full power, compressor bleed air is not required and valves  60 A,  60 B and  80 A,  80 B are closed since the engines are at full power. Valves  54 A,  54 B and  73 A and  73 B are open. Valves  62  and  82  are open and modulating airflow to the canards  24 A and  24 B. After takeoff, the left and right canards  24 A and  24 B are no longer required and are retracted and valves  54 A,  54 B and  73 A,  73 B are closed. Upon approach to and landing, the left and right canards  24 A and  24 B are again extended. Because the power produced by the engines  46 A- 46 D is greatly reduced, the valves,  53 A,  53 B and  73 A and  73 B are again opened as well as valves  60 A,  60 B and  80 A,  80 B, because both fan and compressor air flow is needed. A crossover duct  86  having flow control valve  87  therein connects duct  56 C to duct  76 C and is opened should an engine failure occur. 
     It should be noted that airflow for the flaps and canard can be provided by an auxiliary power unit coupled to an air pump or an electric motor driving an air pump could also be used. However, air extracted from the propulsion system is presently preferred. 
     Referring back to  FIG. 2 , the canard actuation system  26  includes two ball screw actuators  90  and  92  each having motors  94  and  96  pivotally attached to aircraft structure  98 . Each actuator  90  and  92  have screw shafts  100  and  102 , which engage nut members  106  and  108  rotatably mounted on the canards  24 A and  24 B. Thus rotation of the screw shafts  100  and  102  will cause the canards to extend or retract. For purposes of illustration the canard  24 A is shown extended and the canard  24 B are always extended and retracted in unison. It should also be noted that other actuation systems may be used. 
       FIG. 8  discloses a pictorial representation of the major structural components of the above described cargo version of the aircraft, designated by numeral  10 , a tanker version  10 A and a weapons carrier (bomber) version  10 B. Aircraft  10 A and  10 B are generally similar to the aircraft  10 , except they have no retractable canards  24 A and  24 B, and the air pressurization system  52  is removed. They are not required for these configurations. However, the external contours of the aircraft  10 A and  10 B remain otherwise similar to the aircraft  10 . All three versions of the aircraft include a common center fuselage section  110 , having a recess  111 , a nose section  112 , propulsion sections  114 A and  114 B and wing sections  116 A and  116 B and aft section  118 . The recess  111  defines recess top surface  124  and side surfaces  126  and  128 . The recess is sized for receiving any one of the plurality of mission specific compartments systems, as described below. In the aircraft  10 B (bomber version), a weapons hay  120  in the center fuselage section  110  forming an assembly  110 A. In the aircraft  10  (cargo version) and aircraft  10 A (fuel tanker) a cargo container section  122  is installed in common fuselage section forming assembly  110 B. 
     Each version of the compartment systems  122  includes a lower surface  144  which, when the compartment system is inserted within the recess  111 , of center section  110 , defines a portion of the aircraft exterior surface. Each version of the compartment system also defines a top surface  134 , side surfaces  136  and  138 , front surface  135  and rear surface  137 . Upon installation of the compartment system into the recess  111 , all surfaces of the compartment system, other than lower surface  144 , are disposed within aircraft exterior surface. Top surface  134  and side surfaces  136 ,  138  are disposed proximate the adjacent surfaces  124 ,  126 , and  128  of recess  111 , within the aircraft exterior surface. 
     Referring to  FIG. 9 , the aircraft  10 , cargo container section  122  includes a floor section  124 , and the aft section  118  is open and includes a door  125 . Referring to  FIGS. 10 and 11 , in the aircraft  10 A, there is no aft door and fuel tanks  126 A and  126 B are installed. An aft section  118  bulkhead  107  is installed. Referring to  FIG. 12  in the aircraft  10 B, the weapons bay  120  includes auxiliary fuel tank  130 , a main weapons bay  120 A having bomb hay doors  124 A and  124 B and side missile compartments  126 A and  126 B with doors  128 A and  128 B. The weapons hay  120 , includes bulkheads  140  that partition off the main weapons bay  120 A and missile compartments  126 A and  126 B. 
     Thus it can be seen that the flying wing aircraft design can accommodate three separate missions within a common external configuration of the aircraft. Between the weapons carrier and fuel system and cargo system aircraft a commonality is projected at 90 percent commonality for the wing sections  116 A and  116 B. 80 percent commonality between the propulsion system sections  114 A and  114 B and a 60 percent commonality between center section  110 . 
     While the invention has been described with reference to a particular embodiment, it should be understood that the embodiment is merely illustrative as there are numerous variations and modifications which may be made by those skilled in the art. Thus, the invention is to be construed as being limited only by the spirit and scope of the appended claims. 
     INDUSTRIAL APPLICABILITY 
     The invention has applicability to the aircraft manufacturing industries.