Abstract:
A wingtip for extending a wing of an aircraft having a NACA 23012 airfoil. The wingtip has an airfoil design for directing and associated wingtip vortex outward and upward to thereby increase the effective wingspan of the aircraft and to reduce induced drag. The wingtip is preferably molded and comprises a fuel tank bay, internal antenna, landing light and navigation light.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to wing tips for general aviation aircraft. More particularly, the present invention relates to a wing tip particularly designed for a Beechcraft Bonanza type aircraft. 
       BACKGROUND OF THE INVENTION 
       [0002]    General aviation aircraft are a class of airplanes comprising business and personal aircraft which are not military or airline transport aircraft. One of the most popular types of general aviation aircraft is a Beechcraft Bonanza type aircraft, in particular a Bonanza or Baron model aircraft. The production of these aircraft started in 1947 and many are still flying today. Although several different models have been made over the years reflecting new and improved technology, the models still use the same airfoil: NACA 23012. 
         [0003]    Although the airfoil of the models does not represent recently developed technology, bonanzas are well known for their aerodynamic efficiency and good performance. However, there remains room for improvement, particularly with respect to wingtip design. 
         [0004]    In accordance with the present invention, an add-on or replacement wingtip is provided which is particularly well-suited for installation on Beechcraft bonanza or Baron aircraft, hereinafter collectively referred to as Bonanza aircraft. Installation of a wingtip of the present invention on a Bonanza aircraft provides additional lift while lowering the induced drag of the Bonanza wing and the overall total drag of the wing. Furthermore the wingtip of the present invention is capable of holding approximately one hour of additional fuel thus providing extended range to the aircraft. Still further the wingtip of the present invention is designed with additional dihedral which improves the spiraling stability of the Bonanza aircraft. As a result of adding wingtips of the present invention to Bonanza aircraft, the aircraft obtains an improved climb rate while enjoying lower spiraling moment, longer range and a higher true airspeed. 
         [0005]    It will be appreciated by those skilled in the art that a preferred embodiment of the present invention is disclosed herein as a wingtip for Bonanza aircraft. However, the present invention can be adapted for use on other similar type general aviation aircraft having the same or similar airfoil wing. Such other similar type general aviation aircraft are intended to be included within the broad scope of the present invention. 
         [0006]    Further understanding of the present invention will be had from the following specification and claims taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of an embodiment of a left wingtip of the present invention; 
           [0008]      FIG. 2  is a top plan view of a right wingtip which is a mirror image of the preferred embodiment of  FIG. 1 ; 
           [0009]      FIG. 3  is a side elevation view of the wingtip of  FIG. 2 ; 
           [0010]      FIG. 4  is a front elevation view of the wingtip of  FIG. 1 ; and 
           [0011]      FIG. 5  is a somewhat schematic view illustrating the pressure pattern obtained by the preferred embodiment of the wingtip of  FIGS. 1 . 
       
    
    
     SUMMARY OF THE INVENTION 
       [0012]    A wingtip for extending a wing of an aircraft incorporates a series of airfoils intended to direct the associated wingtip vortex outward and upward to thereby increase the effective wingspan of the aircraft and to reduce induced drag. The wingtip is preferably molded from composite materials, carbon fiber and/or fiberglass, and comprises a fuel tank bay, internal antenna, landing light and navigation light. 
       DESCRIPTION OF THE INVENTION 
       [0013]    Now referring to the Figures, a preferred embodiment of a wingtip of the present invention is shown in  FIGS. 1-4  and indicated generally by the numeral  10 . It will be appreciated that both left and right wingtips are shown and that each is a mirror image of the other. Generally speaking, wingtip  10  has an aerodynamic shape having an inboard airfoil identical to the existing tip of a wing to be extended, i.e., NACA 23012, and a continuously changing airfoil shape to its tip functioning to direct the associated vortex generated by lift of the wing upward and outward from the tip. 
         [0014]    Wingtip  10  comprises an inboard section  12  which has a hollow interior  14  which is sized and shaped to fit closely telescopically over outboard end  16  of an associated wing. Section  12  of wingtip  10  has an airfoil shape which is identical to the airfoil shape of outboard end  16  as well as the same angle of incidence. Wingtip  10  is particularly well adapted for installation on Bonanza aircraft which have a NACA airfoil 23012. 
         [0015]    The outward side of section  12  has rib  18  with recessed portion  24  for accommodation of a flux sensor (not shown) or other desired apparatus. Forward of recessed portion  24  and located in the leading edge of wingtip  10  is another recess  26  for locating a landing light (not shown). Outward from recess  26  and also in the leading-edge of wingtip  10  is another recess  28  for locating navigation and strobe lights (not shown). A fuel tank bay  30  holds about 15 gallons of fuel. An internal antenna  31  can be bonded into the skin of the wingtip. 
         [0016]    The aerodynamic shape of wingtip  10  functions to provide additional lift to the associated wing while reducing overall induced drag. Airfoil sections  32 ,  34 ,  36 ,  38 ,  40 ,  42 ,  44 , and  46  are shown for explanatory purposes in  FIGS. 1-5 . Airfoil sections are all perpendicular to the lateral axis of the associated aircraft. The airfoil sections continuously decrease in size from section  12  to outboard tip  48 . The airfoil sections also continuously trend toward being symmetrical with the outermost airfoil section at tip  48  being symmetrical. It will be appreciated by those skilled in the art that tip  48  does not generate lift but in accordance with the present design does contribute to the pressure pattern of wingtip  10 . As illustrated in  FIG. 5 , airfoil sections of wingtip  10  are arranged so that the points of lowest pressure of each section are along a line  50  which curves from point  52  outward to point  54  at tip  48 . 
         [0017]    Leading-edge  56  of wingtip  10  is swept back towards tip  48  while trailing edge  58  is not swept back. As best shown in  FIG. 4  wingtip  10  is swept slightly upwardly towards tip  48  which upward sweep provides additional dihedral to the associated wing. 
         [0018]    The present invention provides many advantages to an aircraft. The wingtip decreases overall drag of the wing by reducing induced drag while only slightly increasing form drag. On a Bonanza aircraft wingtip  10  adds approximately 11 ft. 2  of total wing area and provides additional lift to improve climb rate due to lower wing loading. The additional dihedral provided by wingtip  10  lowers the spiraling moment of the associated aircraft. Wingtip  10  holds approximately 15 gallons of fuel for a Bonanza aircraft thus providing longer-range due to increased fuel capacity. Longer-range is also obtained because the aircraft will obtain a higher true airspeed due to increased span efficiency, lower drag shape, as well as lower drag from use of flush antennas. 
         [0019]    In operation, the pressure pattern of the wingtip provides a lowest pressure point all of the way to tip  48  thus directing the associated wingtip vortex ou, toward from wingtip  10  and upward. This functions to reduce induced drag associated with the creation of lift for the aircraft wing. 
         [0020]    While a preferred embodiment of the present invention has been disclosed in the foregoing disclosure in the context of Bonanza aircraft, it will be appreciated by those skilled in the art that this invention is useful for other similar aircraft wing. It is intended that the present invention may be subject to variation and modification within the broad scope of the invention. Therefore, it will be appreciated by those skilled in the art that the present invention is intended to be limited only by the scope of the following claims.