Patent Publication Number: US-2002009366-A1

Title: Helicopter blade assembly adapted

Description:
[0001] This application is a continuation of U.S. Patent Application 08/730,871 filed Oct. 18, 1996. 
    
    
     
       TECHNICAL FIELD  
       [0002] The present invention relates to helicopters. More specifically the present invention relates to a helicopter blade assembly.  
       [0003] 1. Background of The Invention  
       [0004] The helicopter, when introduced, was a revolutionary aircraft. With its ability to take off and land vertically, the helicopter was able to accomplish maneuvers that no fixed wing craft could perform. Unfortunately, the aerodynamics of rotating blades impose a limit on helicopter maximum forward speed (apart from drag, motive power and other considerations).  
       [0005] The standard single, tandem or lateral-twin rotor helicopter blades provide lift as well as forward impetus. Even with the addition of independent propulsion from either a propeller or jet engine, the individual blade flight characteristics present the following problem at high speeds. In forward flight, a blade advances into the airstream and then retreats. In high speed forward flight, the retreating blade speed may match the speed of the advancing airstream, producing a zero lift condition. The advancing blade then carries the full lift load, with a destablilizing overturning moment on the craft itself. At speeds below this condition, cyclic pitch control can successfully compensate for the potential instability. There is a tilt-rotor design which solves this problem by directing the forced flow of air in the direction required, by rotating engines and blades altogether. The following is offered as a less complex mechanical solution to this problem.  
       [0006] 2. Summary of The Invention  
       [0007] The present invention is a helicopter blade assembly for a craft with either one or two blade-sets. The blade assembly is constructed so that the rotation of the blades provides lift during takeoff and landing. During rapid forward flight, however, the blades sweep out the shape of a virtual disk that acts as a lifting body, so that as the virtual disk cuts rapidly through the air it generates lift. The aircraft to which the assembly is attached requires an independent means of forward propulsion (such as a propeller or jet engine) because the blade assembly is generally not used to pull the helicopter through the air in the same manner as do conventional helicopter blade assemblies.  
       [0008] The shape and, therefore, the lift characteristics of the “swept” disk are controlled by governing the camber of the blades as they rotate, thereby creating the equivalent of ailerons on a fixed wing. This would allow a craft to execute turns and other maneuvers.  
       [0009] Additional objects and advantages of this invention will be apparent from the following detailed description of preferred embodiments thereof which proceeds with reference to the accompanying drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
     [0010]FIG. 1 a  is a bottom view of a rotatable helicopter blade assembly according to the present invention;  
     [0011]FIG. 1 b  is a side view of the rotatable helicopter blade assembly of FIG. 1 a;    
     [0012]FIG. 2 a  is a bottom view of the rotatable helicopter blade assembly of FIG. 1 a  configured to produce a greater symmetrical camber;  
     [0013]FIG. 2 b  is a side view of the rotatable helicopter blade assembly of FIG. 1 a  configured to produce a symmetrical camber;  
     [0014]FIG. 3 a  is a bottom view of the rotatable helicopter blade assembly of FIG. 1 a  configured to produce an asymmetrical camber;  
     [0015]FIG. 3 b  is a side view of the rotatable helicopter blade assembly of FIG. 1 a  configured to produce an asymmetrical camber;  
     [0016]FIG. 4 a  is a bottom view of the rotatable helicopter blade assembly of FIG. 1 a  configured to produce an alternative asymmetrical camber;  
     [0017]FIG. 4 b  is a side view of the rotatable helicopter blade assembly of FIG. 1 a  configured to produce an alternative asymmetrical camber.  
     [0018]FIG. 5 a  is a bottom view of the rotatable helicopter blade assembly of FIG. 1 a  configured to produce a symmetrical camber, and shown while rotating.  
     [0019]FIG. 5 b  is a side view of the rotatable helicopter blade assembly of FIG. 1 a  configured to produce a symmetrical camber, and shown while rotating.  
     [0020]FIG. 6 a  is a bottom view of the rotatable helicopter blade assembly of FIG. 1 a  configured to produce an asymmetrical camber and shown while rotating.  
     [0021]FIG. 6 b  is a side view of the rotatable helicopter blade assembly of FIG. 1 a  configured to produce an asymmetrical camber, and shown while rotating.  
     [0022]FIG. 7 a  is a bottom view of an alternative rotatable helicopter blade assembly according to the present invention.  
     [0023]FIG. 7 b  is a side view of the rotatable helicopter blade assembly of FIG. 7 a.    
     [0024]FIG. 8 a  is a bottom view of the alternative rotatable helicopter blade assembly of FIG. 7 a , configured to produce an asymmetrical camber.  
     [0025]FIG. 8 b  is a side view of the rotatable helicopter blade assembly of FIG. 7 a  configured to produce a greater asymmetrical camber.  
     [0026]FIG. 9 a  is a bottom view of an additional alternative rotatable helicopter blade assembly according to the present invention.  
     [0027]FIG. 9 b  is a side view of the rotatable helicopter blade assembly of FIG. 9 a.    
     [0028]FIG. 10 a  is a bottom view of the alternative rotatable helicopter blade assembly of FIG. 9 a , configured to produce a symmetrical camber.  
     [0029]FIG. 10 b  is a side view of the rotatable helicopter blade assembly of FIG. 9 a  configured to produce a symmetrical camber.  
     [0030]FIG. 11 a  is a bottom view of the alternative rotatable helicopter blade assembly of FIG. 9 a , configured to produce an asymmetrical camber.  
     [0031]FIG. 11 b  is a side view of the rotatable helicopter blade assembly of FIG. 9 a  configured to produce an asymmetrical camber.  
     [0032]FIG. 12 a  is a bottom view of the alternative rotatable helicopter blade assembly of FIG. 9 a , configured to produce an alternative asymmetrical camber.  
     [0033]FIG. 12 b  is a side view of the rotatable helicopter blade assembly of FIG. 9 a  configured to produce a greater alternative asymmetrical camber.  
     [0034]FIGS. 13 a - 13   d  are side views of additional alternative rotatable helicopter blade assemblies according to the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT  
     [0035] A preferred embodiment of a rotatable blade assembly  10 , according to the present invention is shown in FIGS. 1 a - 4   b.  Each of blades  12  has a hinge  14  between a distal end  16  and a proximal end  18 . Each proximal end  18  is fixedly mounted to a mast  20 . A connector  22  connects each distal end  16  to a collar  24 , which is rotatably mounted about a vertically adjustable circular track element  26 , which itself is vertically adjustably mounted about horizontally adjustable hollow post structure  28 . In greater detail, connector  22  connects radially projecting eyelet  30  of collar  24  with downwardly projecting eyelet  32  of blade  12 , so that as blades  12  rotate, collar  24  is pulled about a circular track  34  of track element  26 . A pair of rollers  36  help to guide each connector  22 . Hollow post structure  28  is horizontally adjustably mounted to a circular plate  38  which forms a portion of the frame of a helicopter.  
     [0036] A vertically oriented actuator  44 , typically hydraulic or electrical, adjusts the vertical position of adjustable circular track element  26 , thereby controlling the symmetrical camber of blades  12 . In addition, a horizontal actuator  46  is used to adjust the asymmetrical camber of blades  12  by moving hollow post  28  horizontally relative to blades  12  and mast  20 .  
     [0037] A first set of bearings  50  facilitates the rotation of collar  24  about track  34 . A second set of bearings  52  facilitates the vertical movement of track element  26  relative to hollow post structure  28 . Finally, a third set of bearings  54  facilitates the horizontal movement of hollow post structure  28  relative to circular plate  38 .  
     [0038] It is generally necessary to alter the camber of the blades in response to different flight characteristics. FIGS. 1 a  and  1   b  show blades  12  in a flat configuration. This is similar to the shape of standard helicopter blades. FIGS. 2 a  and  2   b  show rotatable blade assembly  10  configured with circular track element  28  lowered relative to mast  20  and blades  12 , to cause each blade  12  to deform downwardly at distal end  16 . The shape swept out by blades  12  in this configuration is similar to that of an inverted flying disk and has the similar aerodynamic property of providing lift.  
     [0039]FIGS. 3 a  and  3   b  show assembly  10  with hollow post  28  moved to the left to impart an asymmetrical camber to the shape of the virtual lifting body. In this diagram, whichever blade is in the leftmost position will have a downward slope at its distal end, because it will be pulled inwardly by connector  22  which is in turn pulled inwardly due to the position of hollow post  28 . FIGS. 4 a  and  4   b  show assembly  10  with circular track element  26  shifted down slightly relative to the position shown in FIGS. 3 a  and  3   b  relative to the position, causing both distal ends  16  to be tilted slightly more downwardly. The flexibility of the control of the shape of blades  12  shown in FIGS.  1 - 4  is useful in the steering and control of the helicopter to which rotatable blade assembly  10  is affixed. Different shapes are used depending on the desired flight characteristics.  
     [0040]FIGS. 5 a  and  5   b  show the embodiment and symmetrical camber of FIGS. 1 a  and  1   b  but with blades  12  rotating and pulling collar  24  about track  34 . This motion is indicated by the pitch of connectors  22 . FIGS. 6 a  and  6   b  show the same embodiment with camber of FIGS. 4 a  and  4   b  imparted to the blades  12  and with blades  12  rotating and pulling collar  24  about track  34 .  
     [0041]FIGS. 7 a - 7   b  and  8   a - 8   b  show an additional preferred embodiment of the present invention. Elements which are similar to elements of FIGS. 1 a - 4   b  are referenced by the same number as in FIGS. 1 a - 4   b,  but with the addition of a prime mark. As in the embodiment of FIGS.  1 - 4 , the asymmetrical camber of the blades is set by the relative horizontal position of mast  20 ′ with respect to hollow post  28 ′. Rotatable collar  24 ′, however, is vertically stationary. The symmetric camber of blades  12  is set by vertically moving vertically adjustable eyelets-bearing collar  60  which rotates in tandem with collar  24 ′. In addition, connectors  22 ′ are prevented from cutting through the air by guidewheels  62  mounted so that they radially project from collar  24 ′. Bearings  64  facilitate the rotation of ′Collar  60  whereas bearings  66  facilitate the vertical movement of collar  60 .  
     [0042]FIGS. 9 a - 12   b  show an additional alternative preferred embodiment. In these drawings, elements which are analogous to elements in FIG. 1- 4  are referenced with the same reference numbers, but with the addition of a double prime mark. In this embodiment the camber of the blades is determined by the orientation of a swash plate assembly  72 , comprised of nonrotating plate  74 , rotating plate  76 , bearings  78 , and connector attachment sockets  80 . Guide wheels  82  attached to blades  12  guide connectors  22 ′. Two actuators  84  control the vertical position of assembly  72  which determines the symmetric camber of the blades  12  and the orientation of the assembly  72  determines the asymmetric camber of blades  12 . In a swash plate assembly  72 , as in swash plate assemblies in general, the position of the rotatable plate, relative to the nonrotatable plate is fixed, except that the rotatable plate may rotate freely about its axis of rotation. FIGS. 9 a  and  9   b  show blade assembly  10 ″ with swash plate assembly  72  oriented and positioned so that blades  12 ″ have a flat, symmetric camber. FIGS. 10 a  and  10   b  show blade assembly  10 ″ with swash plate assembly  72  oriented and positioned so that blades  12 ″ have a symmetric camber and point downward near distal ends  16 ″. FIGS. 11 a  and  11   b  show swash plate assembly  72  at an angle, imparting an asymmetric camber to blades  12 ″. Finally, FIGS. 12 a  and  12   b  show swash plate assembly  72  at an angle and shifted downward relative to its position in FIGS. 11 a  and  11   b,  thereby imparting an asymmetric camber and with distal ends  16 ″ pointing moved downward with respect to their positions in FIGS. 11 a  and  11   b.    
     [0043]FIGS. 13 a - 13   d  show a number of different types of rotatable blade assemblies according to the present invention that have rigid blades. Although the tips of these blades would not be controllable, like the blades of FIGS.  1 - 12 , they would perform the same function of sweeping out a lifting body. The helicopter on which one of these blade assemblies would be attached would have additional means for effecting steering and control functions. Parts in these drawings which are analogous to parts in FIGS.  1 - 4  are referenced by the same number but with a 1 in front of it  13   a,  a 2 in front in FIG. 13 b,  a 3 in front in FIG. 13 c  and a 4 in front in FIG. 13 d.  Blades  112  of FIG. 13 a  turn down slightly near distal end  116 , creating a lifting body that is somewhat “frisbee” shaped when spun rapidly. Blades  212  of FIG. 13 b  have a sharper downward turn toward distal ends  216 . Blades  312  of FIG. 13 c  have both a rigid downward camber over its length and a slight thickening near distal end  316 . Blades  412  of FIGS. 13 d  slope downward from proximal ends  418  to points  498  about three quarters of the way to distal end  416 .  
     [0044] It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments of this invention without departing from the underlying principles thereof. The scope of the present invention should, therefore, be determined only by the following claims.