Patent Publication Number: US-2023132705-A1

Title: Sliding Panel for Download Alleviation on High-Speed VTOL Aircraft

Description:
TECHNICAL FIELD 
     The present disclosure is directed to vertical takeoff and landing aircraft. 
     BACKGROUND OF THE INVENTION 
     Vertical takeoff and landing (VTOL) aircraft have valuable capabilities for both civilian and military applications. Such vehicles can access tough to reach locations, for example, eschewing the need for long runways. One drawback to these vehicles is they tend to have lower maximum speeds than other conventional airplanes. 
     BRIEF SUMMARY OF THE INVENTION 
     One embodiment under the present disclosure comprises a wing apparatus for an aircraft, comprising: a wing body configured to provide lift to an aircraft during flight; a fowler flap apparatus comprising a fowler flap, a first attachment means and a first deployment means, the first attachment means configured to couple the fowler flap to the wing body, and the first deployment means configured to deploy and retract the fowler flap aft of the wing body; and a sliding panel apparatus comprising a sliding panel, a second attachment means, and a second deployment means, the second attachment means configured to couple the sliding panel to the wing body, and the second deployment means configured to deploy and retract the sliding panel from a prone position on top of the wing body. 
     Another embodiment comprises an aircraft comprising: a fuselage; and one or more wings coupled to the fuselage and configured to provide lift during forward flight, the one or more wings comprising; a tilt rotor configured to rotate between generally vertical and generally horizontal axes of orientation, the tilt rotor comprising one or more blades configured to provide thrust along the tilt rotor’s axis of orientation; a fowler flap apparatus comprising a fowler flap, a first attachment means and a first deployment means, the first attachment means configured to couple the fowler flap to the wing body, and the first deployment means configured to deploy and retract the fowler flap aft of the wing body; and a sliding panel apparatus comprising a sliding panel, a second attachment means, and a second deployment means, the second attachment means configured to couple the sliding panel to the wing body, and the second deployment means configured to deploy and retract the sliding panel from a prone position on top of the wing body. 
     Another embodiment comprises a method of operating an aircraft, comprising: powering up an engine of the aircraft; directing a plurality of tilt rotors comprising the aircraft in a generally vertical axis of orientation, the plurality of tilt rotors comprising one or more blades; deploying a sliding panel from a wing comprising the aircraft, the sliding panel configured to be deployed from at least partially within the wing to a prone position on top of the wing; deploying a fowler flap from the wing, the fowler flap configured to be deployed from at least partially within the wing to a position aft of the wing; providing lift to the aircraft via the one or more blades; tilting the plurality of tilt rotors to a generally horizontal axis of orientation; and providing thrust for forward flight to the aircraft via the one or more blades. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 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 will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
         FIGS.  1 A- 1 B  are diagrams of a prior art fowler flap; 
         FIGS.  2 A- 2 B  are diagrams of a wing embodiment under the present disclosure; 
         FIGS.  3 A- 3 C  are diagrams of aircraft embodiments under the present disclosure; 
         FIG.  4    is a diagram of a fowler flap embodiment under the present disclosure; 
         FIG.  5    is a diagram of a sliding panel embodiment under the present disclosure; 
         FIGS.  6 A- 6 B  show a sliding panel and wing embodiment under the present disclosure; 
         FIGS.  7 A- 7 C  show a sliding panel and wing embodiment under the present disclosure; 
         FIG.  8    is a flow chart of a method embodiment under the present disclosure; and 
         FIG.  9    is a flow chart of a method embodiment under the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIGS.  1 A- 1 B , a prior art fowler flap  110  can be seen in an aircraft wing  100 . Fowler flaps are often used in commercial airplanes and other aircraft that fly at airspeeds within the transonic region. They can be helpful by increasing an effective size of a wing  100 .  FIGS.  1 A and  1 B  both show wings  100  with the same weight. But when the fowler flap  110  is deployed, in  FIG.  1 B , more air is flowing over and under the wing, creating more lift. Thus the greater effective wing size. Fowler flaps combine two movements, sliding backwards and downward rotation. Sliding the flap backwards will increase the surface area of the wing, creating increased lift. Downward rotation will increase drag and increase the wing chord and camber. A fowler flap could be requisite on a given VTOL wing based on its high-speed cruise design, but also maintaining low speed flight lift capability. Extending a fowler flap in the chordwise direction increases the sum projected area of the aircraft thereby increasing download and reducing effective rotor thrust. 
       FIGS.  2 A- 2 B  show embodiments of a wing  200  with a sliding panel  220  for download alleviation under the present disclosure.  FIG.  2 A  shows the closed position, with a similar profile to  FIG.  1 A .  FIG.  2 B  shows the open position, with fowler flap  210  extended back and down from wing  200 , and sliding panel  220  moved upward along the top surface of wing  200 . Sliding panel  220  is preferably as close as possible to the top surface of wing  200  so as to minimize drag. Sliding panel  220  preferably comprises a portion of the top of the wing airfoil. The movement of the sliding panel  220  and the flap  210  will create an open space between the aft face of the wing box and the leading edge of the deployed fowler flap assembly. During vertical movements like takeoff and landing, and transitions to/from vertical to cruise, the open space will decrease the sum projected area of the aircraft thereby decreasing download and increasing effective rotor thrust. 
     Besides the greater efficiency in vertical maneuvers, the embodiments described herein will allow VTOL and high speed VTOL (HSVTOL) aircraft to utilize longer or thinner wings which allow for higher speed. HSVTOL wings are designed with a minimum thickness driven by the rotor cross drive shaft diameter, thereby driving the chord length to make a wing that performs well at transonic cruise speeds. Unfortunately, such wing geometries perform poorly at low airspeeds. Traditional plain flaps would not add sufficient lift to these thin transonic-speed designed wings during low speed flight, therefore the chord extension and camber increase provided by a fowler flap makes them capable of generating requisite lift at low airspeed. The sliding panels described herein allow for download alleviation so that the described fowler flaps don’t hamper a VTOL’s capability in vertical maneuvers, while simultaneously allowing for the longer chord and thinner wings needed for high speeds. 
       FIGS.  3 A- 3 B  show a top-down view of an HSVTOL embodiment under the present disclosure. HSVTOL  300  comprises a fuselage  310 , wings  320 , and tilt rotors  350 . In  FIGS.  3 A- 3 B  tilt rotors  350  are directed upward, such as during takeoff or landing. In  FIG.  3 A  sliding panel  330  and fowler flap  340  are in a stowed position along wings  320 . In  FIG.  3 B  the sliding panel has been moved on top of wing  320  and fowler flap  340  has been extended backward and/or downward. Brackets  335  can be used to extend the fowler flap  340 , revealing a gap between the fowler flap  340  and wing  320  and sliding panel  330 . In  FIG.  3 B , the HSVTOL  300  is shaded to assist in showing the open gap or path created when the sliding panel  330  and fowler flap  340  are deployed. The gap creates different downloads between HSVTOL in  FIG.  3 A  and  FIG.  3 B . Brackets  335  may optionally extend further up along or within wing  320  to allow for the actuation of the sliding panels  330 . Alternatively, sliding panels  330  may move along separate brackets.  FIG.  3 C  shows the wing  320  of  FIG.  3 B , but from a side view. The sliding panel  330  can be seen on top, and the fowler flap  340  deployed away from the wing  320 , revealing an open space for air flow. 
     The attachment to the wing, actuation, and movement of fowler flaps  340  and sliding panels  330  may be accomplished by any appropriate means. Brackets, rotational screws, ball screws, tracks, linear actuators, rotational actuators, springs, rails, bolts, or other means may be used. One possible embodiment of a fowler flap is shown in  FIG.  4   . Fowler flap  400  can be coupled to a wing or wing spar (not shown) by attachments  410 . A plurality of brackets  430  can be coupled and rotate about joints  440 . Actuators  415  and  425  can extend portions of fowler flap  400 . Another actuator  450  may be rotational and can assist in deploying and extending brackets  430  away from the wing or wing spar. Other embodiments may include additional, or fewer attachments  410 , or a different specific configuration of brackets  430 , joints  440 , actuators  415 ,  425 ,  450 . 
       FIG.  5    shows a possible embodiment of a sliding panel. Wing  500  comprises a fowler flap  510  and sliding panel  520 . Wing  500  is shown here with both the fowler flap  510  and sliding panel  520  deployed. Brackets  515  can be actuated to extend fowler flap  510 , while brackets  525 ,  535  can be actuated to move sliding panel  520  on top of wing  500 . Sliding panel  520  preferably rests on, or very close to, the top surface of wing  500  so as to minimize drag once forward movement has begun. 
       FIGS.  6 A- 6 B  show another embodiment of a sliding panel - this one a “minivan door” style embodiment. Tracks  650  can attach or be integrated into wing  620 . In  FIG.  6 A , sliding panel  640  and fowler flap  630  are not deployed. Deployment of the sliding panel  640  can be achieve with 90-degree gearboxes  635 ,  645  and ball screws  637 ,  638 ,  647 ,  648 . The 90-degree gearboxes allow the rotation of the spanwise ball screws  637 ,  647  to actuate the chordwise ball screws  638 ,  648  to create the fore and aft motions for the door and flap assemblies to deploy and retract.  FIG.  6 B  shows the sliding panel  640  and the fowler flap  630  both in deployed positions. Ball screws  637 ,  647  can connect to the gearboxes  635 ,  645  from a controller or other component in an airplane. Wheels  670  connect to the sliding panel  640  and can be inserted into tracks  650  and allow sliding panel  640  to move along tracks  650 . 
       FIGS.  7 A- 7 C  show an aircraft embodiment  700  making use of the sliding panel of  FIGS.  6 A- 6 B .  FIGS.  7 A- 7 C  also show how an aircraft can have a wing with both a sliding panel and a more traditional fowler flap in different portions of the wing. In  FIG.  7 A , wing  720  has a sliding panel  740  and fowler flap  730 , both in retracted position. Tracks  750  allow for movement of the sliding panel  740 . In this embodiment, the sliding panel  740  only comprises a portion of wing  720 . Outboard of the sliding panel  740  there is a traditional aileron/flap  760 . 
       FIG.  7 B  shows wing  720  with deployed sliding panel  740  and fowler flap  730 , as well as downward pointing aileron/flap  760 . Aileron/flap  760  can, in some embodiments, also be directed upward, such as when braking.  FIG.  7 C  shows wing  720  and aircraft  700  from a perspective view. Although not shown in the illustrations for clarity, the rotating pylon containing the lifting rotor assembly would be mounted at the most outboard location at the wingtips. 
     One possible method embodiment of the present disclosure is a method of operating an aircraft  800 , seen in  FIG.  8   . Step  810  is powering up an engine of the aircraft. Step  820  is directing a plurality of tilt rotors comprising the aircraft in a generally vertical axis of orientation, the plurality of tilt rotors comprising one or more blades. Step  830  is deploying a sliding panel from a wing comprising the aircraft, the sliding panel configured to be deployed from at least partially within the wing to a prone position on top of the wing. Step  840  is deploying a fowler flap from the wing, the fowler flap configured to be deployed from at least partially within the wing to a position aft of the wing. Step  850  is providing lift to the aircraft via the one or more blades. Step  860  is tilting the plurality of tilt rotors to a generally horizontal axis of orientation. Step  870  is providing thrust for forward flight to the aircraft via the one or more blades. 
     Another possible method embodiment under the present disclosure is shown in  FIG.  9   .  FIG.  9    shows a method of manufacture  900  of an aircraft. Step  910  is providing a fuselage. Step  920  is coupling one or more wings to the fuselage, the one or more wings configured to provide lift during flight and wherein the one or more wings comprise; a tilt rotor configured to rotate between generally vertical and generally horizontal axes of orientation, the tilt rotor comprising one or more blades configured to provide thrust along the tilt rotor’s axis of orientation; a fowler flap apparatus comprising a fowler flap, a first attachment means and a first deployment means, the first attachment means configured to couple the fowler flap to the wing body, and the first deployment means configured to deploy and retract the fowler flap aft of the wing body; and a sliding panel apparatus comprising a sliding panel, a second attachment means, and a second deployment means, the second attachment means configured to couple the sliding panel to the wing body, and the second deployment means configured to deploy and retract the sliding panel from a prone position on top of the wing body. 
     Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.