Abstract:
A vertical take-off and landing (VTOL) aircraft comprises (1) a fuselage having a front end, a rear end and two lateral sides, the fuselage defining a substantially horizontal central longitudinal axis of the aircraft; (2) an aircraft tail arranged at the rear end of the fuselage and including a rudder and an elevator on each side of the fuselage with movable surfaces for controlling the aircraft; and (3) a wing on each side of the fuselage having a front edge, a trailing edge and an upper surface extending from the front edge to the trailing edge. Means are provided for increasing the speed of an airstream flowing over the upper surface of each wing.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application is a continuation of U.S. patent application Ser. No. 11/114,836, filed Apr. 26, 2005, entitled “VTOL PERSONAL AIRCRAFT” (now U.S. Pat. No. 7,461,811), which, in turn, is a continuation-in-part of U.S. patent application Ser. No. 10/242,036, filed Sep. 11, 2002, now U.S. Pat. No. 6,886,776. This application also claims priority from U.S. Provisional Patent Application Ser. No. 60/661,554, filed Mar. 14, 2005. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to a small, affordable short take-off and landing (STOL) and/or vertical take-off and landing (VTOL) aircraft called a “Personal Aircraft”, or “PAC” for short. The present invention relates efficient and relatively simple means for producing vertical, upward thrust beneath the wing(s) of the aircraft. 
   A typical winged aircraft comprises an elongate fuselage forming a passenger compartment for pilot and passenger(s). The fuselage has two lateral sides and is arranged along the longitudinal axis of the aircraft that is aligned with the direction of forward motion. 
   The aircraft has one or more elongate fixed wings which are attached to the fuselage and extend outward from the two lateral sides thereof. The wing(s) have a leading edge and a trailing edge and a longitudinal wing axis that extends perpendicular to the aforementioned longitudinal axis of the aircraft. The center of gravity of the aircraft is located in a region between the leading edge and the trailing edge of the wing(s). Each wing has a first wing component extending outward on one side of the fuselage and a second wing component extending outward on the opposite side of the fuselage. 
   The aircraft has a prime mover with a propeller or other means for propelling it forward so that air flows over the wings and they provide lift. The aircraft also has at least one “thruster” disposed in the wing component on each side of the aircraft for providing additional vertical lift, especially when the aircraft is moving forward slowly or not moving at all. 
   An aircraft of this type is more fully disclosed in the aforementioned U.S. Pat. Nos. 6,886,776 and 7,461,811, the disclosures of which are incorporated herein by reference. 
   SUMMARY OF THE INVENTION 
   A principal object of the present invention is to simplify the mechanism for providing vertical lift to a winged aircraft when in the STOL or VTOL mode. 
   A further object of the present invention is to enhance the vertical lift produced by the wing(s) of an aircraft when the aircraft is flying slowly. 
   These objects, as well as further objects which will become apparent from the discussion that follows, are achieved, in accordance with the present invention, by providing a thruster in a wing component on each side of the aircraft, which thruster comprises: 
   (1) at least one shaft mounted for rotation in the respective wing component and extending substantially parallel to the wing axis; and 
   (2) a plurality of fan blades attached to each shaft for movement of air upon rotation of the respective shaft. The shafts in the wing components are rotated by one or more prime movers, preferably arranged in the fuselage. 
   Preferably, the fan blades which are attached to each shaft, are elongate and extend substantially parallel to the shaft. Preferably also, a shroud is arranged in each respective wing components, adjacent the fan blades, for directing the air moved by the fan blades. The shroud may be arranged parallel to the upper surface of the wing, above the fan blade, or substantially perpendicular to the upper surface behind the fan blades. The shroud is preferably moveable for directing air either rearward over the upper surface of the wing component, to increase the speed of the air over this surface, or downward to provide vertical lift. 
   In an advantageous embodiment of the present invention, the shaft in each respective wing component is moveable in the vertical direction between a first position, in which the fan blades protrude upward from the upper surface of the wing component, and second position in which the fan blades are substantially contained between the upper surface and the lower surface of the wing component. 
   The thruster can comprise either one shaft, with an associated plurality of fan blades, or two shafts, each with a plurality to blades, mounted for rotation in each wing component substantially parallel to the wing axis and to each other. The two shafts are preferably driven in opposite directions by a common prime mover, either directing air downward in the space between them or directing air downward in a Roots-type blower configuration. 
   The shafts can also be rotated in the same direction so that both fans operate to move the air rapidly over the upper surface of the wing component. 
   When the thruster operates to increase the speed of the air moving over the upper surfaces of the wing components, it decreases the pressure at the surface in accordance with Bernoulli&#39;s principle, thereby increasing the lift of the wing. 

   
     BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  is a perspective view of an aircraft incorporating a thruster within each wing component, according to a first preferred embodiment of the present invention. 
       FIG. 2  is a cross sectional view of the wing in the aircraft of  FIG. 1 , showing details of the thruster and its surrounding shrouds. 
       FIG. 3  is a perspective view of an aircraft, according to a second preferred embodiment of the present invention. 
       FIG. 4  is a top view of the aircraft of  FIG. 3 . 
       FIG. 5   a  is a cross sectional view of the wing of either the aircraft of  FIGS. 1 and 2 , or of  FIGS. 3 and 4 , showing a thruster which speeds the flow of air over the upper surface of the wing. 
       FIG. 5   b  is a cross sectional view of the wing of either the aircraft of  FIGS. 1 and 2 , or of  FIGS. 3 and 4 , showing a plurality of thrusters which are moveable into and out of the air stream over the upper surface of the wing. 
       FIG. 6  is a cross sectional view of an aircraft wing according to an alternative embodiment of the present invention. 
       FIG. 7  is a cross sectional view of an aircraft wing according to a further alternative embodiment of the present invention. 
       FIG. 8  is a perspective view of an aircraft according to a third preferred embodiment of the present invention. 
       FIG. 9  is a cross-sectional view of the wing of the aircraft of  FIG. 8 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The preferred embodiments of the present invention will now be described with reference to  FIGS. 1-9  of the drawings. Identical elements in the various figures are designated with the same reference numerals. 
     FIGS. 1 and 2  of the drawings show a first preferred embodiment of the aircraft according to the present invention.  FIGS. 3 and 4  illustrate a second preferred embodiment,  FIGS. 8 and 9  illustrate a third preferred embodiment thereof. The “thruster” incorporated into each wing component of the aircraft is illustrated in the concept diagrams of  FIGS. 2 ,  5   a ,  5   b ,  6 ,  7  and  9 . None of these diagrams are drawn to scale. 
     FIGS. 1 and 2  illustrate a first preferred embodiment of the present invention. This embodiment includes a winged aircraft  10  having an elongate fuselage  12  which extends along the longitudinal axis  14  of the aircraft. The fuselage has a top, bottom and two lateral sides and forms a passenger compartment for at least one person (e.g., the pilot) to be carried by the aircraft. 
   The aircraft  10  has a fixed wing  16  having a leading edge  18  and trailing edge  20  and a longitudinal wing axis  22  between them extending perpendicular to the longitudinal axis  14  of the aircraft. 
   The fixed wing is attached to the fuselage and extends outward from the two lateral sides thereof, there being a first wing component  24  extending outward from the right lateral side of the fuselage and a second wing component  26  extending outward from the opposite, left lateral side of the fuselage. 
   According to the invention, at least one “thruster” is disposed on each wing component to assist in providing vertical lift to the aircraft. This thruster includes a shaft  28 , mounted for rotation in the respective wing component and extending substantially parallel to the wing axis  22  and a plurality of fan blades  30  attached to the shaft  28  for movement of air upon rotation of the shaft. 
   The shaft  28  in each wing component is driven by a prime mover  32  disposed within the fuselage  12 . This prime mover may be any type of internal combustion engine or even an electric motor. 
   The aircraft  10  is propelled forward in a conventional manner by means of a forward mounted engine which drives a propeller  34  at the front of the aircraft. 
   As is best seen in  FIG. 2 , the thruster is mounted for rotation within the wing. A first shroud  36  is moveable vertically to direct air either downward, thereby providing vertical lift to the aircraft when the shroud is in an upward position, or rearward over the upper surface of the wing when the shroud is in the lower position. 
   Similarly, a second shroud  38  arranged on the lower surface of the wing component is moveable between a first, rearward position, in which a downwardly extending channel  40  remains open, or in a second, forward position in which the channel  40  is closed. 
   The fan blades  30  on the shaft  28  may be provided with moveable tip elements  42  which extend forward in the direction of motion to collect air during the upward and rearward motion of the respective fan blade  30  (elements  42   a  and  42   b ) and which are moved rearward of the tip of the respective fan blade  30  as the blade moves downward and forward (elements  42   c  and  42   d ). In this way, air may be collected and then directed downward through the channel  40 , so that only a minimum of the air will be recycled upward again to the top surface of the wing. 
   The center of gravity  44  of the aircraft lies in the fuselage between the leading edge  18  and the trailing edge  20  of the wing, and preferably forward of the shaft  28 , as shown in  FIG. 2 . 
     FIGS. 3 and 4  illustrate a second preferred embodiment of the aircraft according to the invention. In this case, a pair of ducted fan units  46  are arranged on both sides of the fuselage  12  to provide both vertical lift, when the aircraft is operating in a VTOL mode, and forward propulsion for the aircraft when the aircraft is flying forward. The ducted fan units are mounted for rotation about a common axis  48  which, like the wing axis  22 , is perpendicular to the central longitudinal axis  14  of the aircraft. The ducted fan units  46  are powered either by a common internal combustion engine  49  arranged in the forward section of the fuselage  12 , or powered by separate, independent IC engines disposed within the fan units themselves. When powered by an engine in the fuselage, the ducted fans are driven by rotating shafts  51 . 
   As shown in  FIG. 4 , the shafts  28 , bearing the shaft blades  30 , may be mounted for rotation at each wing tip and at points adjacent the fuselage and the engine  32 . If additional support is necessary, the fan blades may be interrupted at points along the wing and the shaft  28  supported by internal wing braces  50 , shown in dashed lines. 
     FIGS. 8 and 9  illustrate still another preferred embodiment of the present invention in which the shaft  28  with its rotatable blades  30  are mounted beneath a shroud  52  that constricts the air driven by the fan blades  30  to flow over the upper surface  54  of the wing. The shroud  52  is supported, fore and aft of the shaft  28  and blades  30 , by vertically extending braces  56  and  58 , respectively. 
   The “thruster” formed by the engine  32 , rotatable shaft  28  and fan blades  30  can assume a number of configurations, as illustrated in  FIGS. 5   a ,  5   b ,  6  and  7 .  FIG. 5   a  shows a single shaft  28 , with a plurality of fan blades  30  having forwardly extending tip elements  31 . The diameter D of the fan is substantially twice the thickness of the wing. For this purpose, the shaft  28  is mounted substantially at the level of the upper surface of the wing. 
     FIG. 5   b  shows an alternative embodiment having a plurality of thrusters (fans) in which the diameter of each fan is less than the thickness of the wing. In this case, the fans are moveable vertically between an upper position, in which the fan blades protrude through closeable openings in the upper surface of the wing (not shown), and a lower position in which the fan blades are wholly contained within the wing. Closeable openings are provided on the upper surface of the wing to allow the fan blades to protrude. 
   As shown in  FIG. 5   b , any number of moveable fans  60  may be provided within a wing. Advantageously, an additional fan  62  is provided at the leading edge of the wing to direct incoming air downward to increase the pressure on the lower surface of the wing. 
     FIGS. 6 and 7  show two alternative embodiments of a thruster which incorporate two horizontal shafts  28   a  and  28   b  surrounded by their respective blades  30   a  and  30   b . The forward shaft  28   a  rotates in such a way that the air received from the upper surface of the wing is accelerated rearward. The second shaft  28   b  may be either rotated in the same direction as the first shaft  28   a , in which case the air is accelerated further in the rearward direction along the upper surface of the wing, or in the opposite direction causing the air to be directed downward through an opening  40  in the wing. 
   In  FIG. 7 , the shafts  28   a  and  28   b  with their respective fan blades  30   a  and  30   b  form a “Roots” type blower which causes the air to be directed downward through two openings  40   a  and  40   b  in the wing. 
   There has thus been shown and described a novel VTOL personal aircraft which fulfills all the objects and advantages sought therefor. Many changes, modifications, variations and other uses and applications of the subject invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings which disclose the preferred embodiments thereof. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention, which is to be limited only by the claims which follow.