US2921404A - Aerial spinning toy - Google Patents

Description

1960 G. w. LIESCHER 2,921,404

AERIAL SPINNING TOY Filed Dec. 24. 1958 INVENTOR United States Patent AERIAL SPINNING TOY George Wright Lescher, Hagerstown, Md.

Application December 24, 1958, Serial No. 782,718

6 Claims. (Cl. 46-74) This invention relates to improvements in aerial toys, particularly those which are intended to automatically, or preferably inherently, convert themselves into horizontally-rotating devices during descent after having been projected upward into the air without such rotation being incurred during ascent.

All such devices as have heretofore come to my attention or appear to have been described publicly seem to be susceptible of considerable improvement if a satisfactory or acceptable toy of this nature is to be achieved. Among the undesirable characteristics of each of these are one or more of the following: (1) Performance during ascent is erratic or undependable in that the device frequently either veers off from an intended vertical flight into an erratic arched trajectory or it goes into undesired premature autorotation almost immediately after launching or during ascent, thus producing more aborted ascents than satisfactory ones; such devices are either devoid of ascent stabilizers or are provided with inconsistentlyfunctioning mechanical ones, not located to the best advantage; (2) the ability of the device to consistently prevent autorotation during ascent and to insure autorotation during descent is dependent, not upon aerodynamic and mass-dynamic principles incorporated inherently into the design of the device, but upon unreliably-functioning mechanisms which are relatively costly, relatively heavy, and require motion of operating parts during flight and a non-positively-actuated configuration change in the device which might or might not occur at the optimum, most desirable point in the flight; (3) performance during descent is either not optimum or it is unreliable in that, in cases where the device is heavy because of basic design reasons, it descends unnecessarily rapidly instead of slowly floating downward while spinning, or due to the in-flight configuration change characteristics, it goes into erratic rotation or semiautorotation or plummets to the ground without spinning at all; and (4) where light weight has been possible by the design it has resulted in a fragile or delicate device and a sacrifice of durability.

I have found that the foregoing disadvantages may be eliminated and that a predictable, simply-constructed, sturdy but light-weight aerial toy of this type, having no in-flight moving parts and requiring no in-flight configuration changes and depending for its proper and optimum-performance operation entirely upon features inherent in. its fundamental design, may be constructed by the. judicious use and placement of masses and aerodynamic planing and stabilizing surfaces. The problem has been found to center around a combination of massdynamic, aerodynamic, and gyroscopic forces, the solution of which has been to provide appropriate control of these forces by causing and permitting inherently their being brought into play and interaction at the appropriate times and in the appropriate sequence.

A primary element in such a device is of course an aerodynamic planing surface, the wing," which during descent must rotatein a circular path. As is well-known in the science of aerodynamics, for stability to be more readily maintained in a free-flight wing at a more or less uniform lift-giving angle of attack it is essential that the center of gravity of such a wing lie well forward of the aerodynamic center, the midway point of the aerodynamic chord, of the wing. For example, center of gravity locations within the range of 20% to 35% back from the leading edge of the mean aerodynamic chord are within workable limits, with around 27% to 29% usually being optimum. Therefore, means must be provided in the device to assure that the center of gravity of the net effective planing surface will lie within these limits; that is, well forward of the aerodynamic center. This may be accomplished in any desired way which will cause the aerodynamically-forward portion of the net effective planing surface to be heavier than the rearward portion, such as by adding material, integrally or separately, at at least a portion of the forward part of the wing, or conversely, by removing material from the rearward part. Weightwise, of course, it is most eflicient in the case of a wing surface of constant, given thickness, for mass to be added at or along, or even ahead of, the leading edge.

A second primary requirement, in such a device having in effect but one principal planing surface freely rotating horizontally, during descent, and about an axis outside at least the major portion of the planing area, is that a counterweight mass be provided to give overall dynamic stability in rotation and to maintain rotation, and to create gyroscopic forces which will maintain the descending device in a near-horizontal attitude instead of permitting the otherwise unsupported counterweight end of the device to fall progressively faster than the air-supported wing end. Likewise, this may be accomplished in any desired way which will cause the center of gravity of the total device to be located a substantial distance laterally from the aerodynamic center of the net effective aerodynamic planing surface, such as by adding mass in the direction of, or at, or beyond one end of the wing. The device of the present invention will autorotate in free-flight descent, in the manner desired,'substantially about this overall center of gravity.

I have found that a wing tending generally to be elongate in shape is better in rotary flight than one not so shaped, as occurs also in the case of planing surfaces travelling in straight paths. 1 have also found that a wing tapering in plan form generally toward the axis of horizontal rotation (approximately the center of gravity of the device) is likewise more eflicient, apparently for the reason that planing surface material unnecessarily located near the axis is less effective in producing lift since its linear speed is less than at points farther outboard.= I have determined further that this tapering form is conducive to increased aerodynamic stability and decreased aerodynamic drag while the device is in longitudinal vertical flight upward. I have also learned, experimentally, that a minimum of planing surface area located on the side of the axis of horizontal rotation (approximately the center of gravity of the device) opposite the primary wing planing surface area results in a maxium of autorotation efficiency and consistency, since planing area located opposite to the primary wing area will function at a negative angle of attack and thus counteract to some extent the lift produced by the primary wing and also tend to induce spirals.

It has been found that each of these factors favorably affects the efliciency of the device when in straight longitudinal vertical flight during ascent and also when in the momentary transition period from free-fall to rotary flight as well as when in autorotation during descent, and thus in both the degree and consistency of performance in each of the stages. While not necessarily considered to con-Z stitute essential elements of my inventifn l have set them "a forth here as contributions to the art and as influencing factors toward the selection of preferred forms and configurations a s Q th .im rqv d effi en ths re mit, but it is not intended that the invention be construed thereby to be limited to these configurations so indicated as having the highest efficiency.

My invention is Considered to reside in the combination of: (1) the forwardly-placed wing center of gravity explained in the foregoing; (2) the laterally-place'd center of gravity of the device, relative to the aerodynamic center of the wing, as also explained in the foregoing; (.3) the introduction of a stationary positionally-fixed stabilizing fin which will restrain the device from inadvertently going intoautorotation during its straight longitudinal flight upward after launching and until after the normal peak of its flight has been reached, and which, by virtue of its location with respect to both the center of gravity of the device and the major effective portion of the wing, will not detrimeutally affect the aerodynamic lift or drag of the wing to a significant. extent when the device is descending in autorotation; and optionally, (4) the introduction of a stationary meansfor accelerating and insuring the transition into autorotation when or shortly after the descent of the device has started, and simultaneously for increasing the aerodynamic stability of the wing when the device is in autorotation.

The latter two stationary elements, each of which is believed to be new in combination in an aerial toy of this type, will be further explained as follows.

I have deduced and found that a small stationary stabilizing fin placed at right angles to the plane of the wing surface and located on the wing side of and aligned in a general direction toward the center of gravity of the device and approximately in the normal line of longitudinal flight of the device in ascent, will stabilize the device throughout vertical flight upward and restrain it from prematurely going into autorotation. I have further found that if such stationary fin is placed in optimum proximity to the center of gravity, it will perform its vertical flight stabilizing function in upward flight and yet, being located sufiiciently close to the center of gravity about which the device rotates in autorotation and thus exerting relatively little blanketing effect over the major effective portion of the wing planing surface, will not adversely affect autorotation of the device during descent. Without such fin, in ascending vertical flight the device is stabilized laterally in one plane only, by the trailing wing itself, and there is no aerodynamic restraint against instability in the corresponding 90 plane, and thus the device will unpredictably, suddenly, and undesirably whip into autorotation. The stationary vertical-flight stabilizing fin which I have added behind and in close proximity to the center of gravity of the device prevents this in upward longitudinal flight but does not measurably'hinder autorotation during descent.

The second stationary element which I have added is a means for aerodynamically guiding and accelerating the device positively into autorotation promptly after the device has begun to free-fall, and simultaneously for increasing the inherent aerodynamic stability of the wing planing surface while it is in descending rotary flight. This is accomplished by introducing camber, or its equivalent, in the wing; that is, by causing the forward and the rearward portions of the wingplaning surface to lie in suitably different planes. 'It has been noted in the foregoing that optimum wing stability may be more readily maintained if the center of gravity of the wing lies about 2 7% to 29% back from the leading edge of the mean aerodynamic chord. While it is possible experimentally to so-balance awing within such a small range,'the normal tolerances of material thicknesses, densities, and manufacturing practicesand techniques make 'itimpracticable to expect such precision in production manufacture. Therefore a wing contourconfiguration which widensthe stability range should-be advantageous. In addition to this widening of thestability range-by introducing camber or its equivalent in the wing contour,the effect of which is to aerodynamigally d p s er a par a thawin a h m n a constant angle of attack of the wing, I have found that such cambering serves effectively to guide the device quite consistently into an attitude and state of horizontal autorotation promptly after the start of free-fall, thereby reducing considerably the element of chance in this transition.

Such camber may take the form of a continuously curving cross-sectional contourof the wing, or it may be applied as a rearward portion of the wing, or as ,a tab appended at the trailing edge thereof, deflected or deflectable out of the plane of the forward portion. In such cases it corresponds in function to a trim tab, fixed or adjustable prior to flight, similar to those used on airplane flight and 'control surfaces, for the purpose of aerodynamically compensating for unbalanced conditions.

Therefore, the principal object of my invention is to provide an aerial spinning toy which will give reliable and optimum performance in that it may, by use of a rubberband hand-launcher, or other equivalent means, be longitudinally projected upward straight and swiftly to heights of to 200 feet without going into autorotation before the optimum peak of the flight is reached, after which-it will inherently and automatically go into near-horizontal continuous autorotation for and during a slow descent.

Another object is to provide such a device which is not dependent, for reliable and optimum performance, upon mechanically-actuated elements therein or thereon, and

which neither requires nor incorporates any moving parts or any in-flight changes in configuration or balance.

Another object is to providesuch a device in a form such that it may be mass-produced with a minimum weight for best performance and in the interest of safety, and at the same time, of durable practical construction.

It is also an object to provide sucha' toy which, through simple construction, may be produced and supplied at minimum cost.

I achieve the above objects in a manner as more particularly set forth herein and shown in the appended drawings in which:

Fig. l is a plan view showing one form of the invention, illustrating primarily the positioning of the vertical-flight stabilizing fin relative to the center of gravity of the device and to the net effective wing planing surface, the forward location of the center of gravity of the counterweighted wing with respect to its aerodynamic center, and the lateral location of the center of gravity of the device with respect to the net effective wing surface;

Fig. 2 is a section view taken on line 22 of Figure 1;

Fig. '3 is a view showing a modified form of the device to illustrate a wing planing surface having a continuouslycurved contour in cross-section;

Fig. 4 is a section view taken on line 44 of Figure 3;

Fig. 5 is a view showing another form of the invention having an adjustably-deflectable wing trailing edge;

Fig. 6 is a section view taken on line 6-6 of Figure 5;

Fig. 7 is a view showing a modified form of the device having a fixedly-deflected wing trailing edge;

Fig. 8 is a section view taken on line 8-8 of Figure 7; and

Fig. 9 is a front elevation view of the device of Figure 7.

Referring now to Figure l the toy is shown in one of its forms as having an elongated wing element which is thin and relatively wide at one end providing a major lifting portion 10 and which tapers to a relatively narrow portion 11 at the opposite end. The wing in this instance has a substantially straight leading edge and an arcuate'shaped trailing edge and is weighted toward the smaller or n'arrowend 1.1 to counterbalance the large end or portion 10 and shift the center ofgravity position of the overall toy toward the smaller end by means of a 'counterweight'12 which may be of soft metal crimped over the end in U- shaped fashion to securely grip the wing; The material from which the wing is constructed may be wood, card- I board, plastic, or any material having the necessary lightness and strength. The counterweight 12 may also be made of materials other than metal and may be otherwise attached to the wing as by gluing or riveting. The counterweight is formed to provide a hook-like portion 13 to act as engagement means for engaging a loop 16 of elastic material, such as a rubber band, for shooting the toy into the air.

The wing portion is weighted toward the leading edge by means of a weight 14 which, like the counterweight 12, may also be of soft metal crimped over the wing leading edge to remain securely fixed thereto. The wing weight 14 is so positioned and of such weight that the position of the center of gravity B of the wing portion 10 will be forward of the aerodynamic center of the wing indicated at circle-C.

A stabilizing fin 15 is fixed to the wing at right angles thereto and in a plane which is substantially in alignment with the center of gravity A and the direction of flight of the device during ascent. The fin is also positioned between the center of gravity A of the toy and the wing aerodynamic center circle-C, and in the instant configuration, may extend from both sides of the wing 10 as shown in Figure 2.

It should be understood that in ascending flight the attitude of the toy is substantially vertical, with the wing end trailing; and that while descending in autorotation the toy spins in a substantially horizontal attitude and approximately about the center of gravity of the toy, with the trailing edge of the wing trailing in an essentially circular path.

Figure 3 illustrates the toy in a different configuration in which a wing 18 is attached to a boom or body element 19, which may be a straight stick of light weight wood, for example, balsa. A head piece or counterweight 20 which may be made of hard wood is attached, as by means of glue, to the forward end of the stick or boom 19 to shift the center of gravity position D of the overall toy toward the boom end of the toy. The head piece is rounded at its forward end and crescent shaped at its aft end to provide two hook-like projections 21, 21' to act as engagement means to which the launching means, such as the rubber band loop 16 of Figure 1, may be attached for projecting the toy upward into the air. The wing 18 is weighted toward one side, or one edge, which is intended to be the forward or leading edge 22 as the toy spins during its descent. The wing is curved from front to rear, or cambered, asshown in Figure 4 to provide a means for accelerating inducement of rotary flight when descent is started, and may be made from any lightweight material which may be formed to retain its curved or cambered shape. I have found that either cardboard or balsa wood may be used for constructing the wing 18 and the wing counterweight may be constructed from two curved pieces 23, 23' of the same material as the wing material attached to the wing, as by gluing one on each side, with the wing sandwiched between as illustrated in Figure 4. The counterweights 23, 23 are used to cause the center of gravity location B of the wing 18 to fall toward the leading edge 22 and between the leading edge and the aerodynamic center circle-C.

The head piece 20 counterweights the weight of the wing 18' to cause the center of gravity of the overall toy to shift toward the smaller end and cause the toy to balance about a center of gravity point D which, in the present configuration, falls on the boom 19. A fixed fin 24 is attached to the boom 19 to extend on both sides thereof as indicated in the section view of Figure 4. The fin lies in a plane which passes approximately through the center of gravity point D and which is perpendicular or normal to the general plane of the wing 18.

Figure 5 illustrates another variation of the toy in which the Wing element 25 is made of deformable material such as thin cardboard which is glued, or fastened by wire staples, to a relatively slender body or wing extension 26 which may be made of lightweight wood, such as balsa. The body 26 extends the full length of the toy in such manner that it forms, in part, the leading edge of the wing and also acts as a counterweight to the weight of the wing to position the center of gravity location G of the wing element at a point between the leading edge and the aerodynamic center circle-C of the wing.

The head piece or counterweight means 27, which may be made of hard wood such as, for example, maple or birch, is attached as by gluing to the end of the body or arm 26 to weight the combination of the parts of the toy toward the smaller end or head end thereof and shift the center of gravity F of the overall combination of parts toward the smaller end thereof and establish such center of gravity at a point F. The head piece is notched as at 28 to provide a hook-like engagement means for attaching the toy to a launcher of the type indicated in Figure 1.

A fixed stabilizing fin 29 extends, in the present instance, from only one side of the device as shown in Figure 6. The fin is positioned in a plane which is perpendicular to the plane of the wing and which passes through or quite near the center of gravity point F of the toy. As in the case ofthe variations of the toy shown in the other Figures 1 and 3, the fin is positioned between the center of gravity F of the toy and the wing aerodynamic center circle-C. As previously mentioned the wing 25 is made of deformable cardboard and the fin 29 may be a part of the wing material and bent up into a fixed position at right angles to the wing.

Although, as already explained, the device will automatically begin autorotationwhen it begins or shortly after it begins to fall after it has reached its maximum height, the toy may be provided with an autorotationinducing means associated with the wing which will help start and sustain such autorotation or spinning during descent. In the case of the combination illustrated in Figure 5, the autorotation-inducing means is in the form of a trimming tab 30 on the trailing edge of the wing which is bent either up or down the desired amount as shown in Figure 6 to remain in a substantially fixed, adjusted position. Since the material of construction is deformable, the tab may be adjusted to any desired position where it will remain in such adjustably deflected position.

In this connection it should be pointed out that if the trimming tab is bent upwardly with respect to the plane of the wing as depicted in Figure 5 and also in Figure 7', the toy will spin during descent in an anti-clockwise direction approximately about the c'enter of gravity of the toy; and that if the trimming tab is bent downwardly with respect to the plane of the wing the toy will spin, in an inverted attitude, in a clockwise direction.

Figures 7, 8, and 9 illustrate the toy in a form adapted for manufacture from one of the plastic materials now available which has the required light weight, strength, and flexibility. In such case the entire toy is of onepiece construction having a wing portion 31, a boom or wing extension 32, a head portion or counterweight 33, a fixed stabilizing fin 34, and a trimming tab 36. Like the head piece of the version shown in Figure 5, the head of the plastic version is provided with a notch at 35 for engagement with a suitable launching device. The boom 32, though shown as being circular, may also be oval or square in cross-section, or as otherwise desired, and extends toward the end of the wing portion to form the leading edge of the wing, and at the same time serve as a counterweighting means to counterweight the wing toward its leading edge and establish the wing center of gravity position I ahead of the wing aerodynamic center circle-C. The trailing edge of the wing 31 is fixedly deflected upwardly to form a trim tab 36, in the instance of Figure 7, to provide an autorotation-inducing means, although it should be understood that if the material used is 7 sufficiently pliable and plastic the trim tab maybe further bent more or less frorn'its' normal deflected position if desired.

With .respectrto the foregoing it is pointed out that the invention is not intended to be construed as being limited to the forms or configurations, kinds of materials or methods of construction which have been shown or indicated by or inferred from the drawings or the specification except as may be limited by the appended claims. For example, it is contemplated that stifieners or reinforcements if and as desired may be added to the wing or to any components or portions thereof in any desired manner, such as by integral design or by the use of components added for that purpose or for, such purpose in combination with other included purposes. It is also contemplated that the counterweigh-ting masses needed to obtain the required locations of the net effective wing center of gravity and the center of gravity of the whole device may be provided by any suitable means desired, such as by the use of integrally incorporated material, by concentrated high-density slugs, by lower density materials of any desired configuration more generally or otherwise suitably distributed or applied. It is to be understood also that the wing shape may be either symmetrical or unsymmetrical and its outline or the outline of any other component or any segment thereof may take any desired form, such as straight, curved, scalloped, etc. It is further contemplated that the trailing edge of the wing and any portion thereof, when utilized as a trimming tab and whether adjustably defiectable or fixedly deflected, may be integrally incorporated in the wing, or the trimming tab may be added as a separate component and suitably affixed thereto in any manner desired.

I claim:

1. In an aerial spinning toy the combination of: an elongated wing; first counterweighting means counterweighting said wing toward one end thereof; second counterweighting means forwardly of the aerodynamic center of said wing counterweighting said wing toward the leading edge thereof; at least one stabilizing fin positioned substantially normal to the plane of said wing and between the aerodynamic center of said wing and the center of gravity of said toy combination; the said fin being substantially in alignment with the said center of gravity of the toy combination for stabilizing said toy in attitude during ascent; an aerodynamic trimming means associated with said wing for accelerating inducement of autorotation of said toy during descentjand engagement means on said toy for engagement with a launching device.

2. In an aerial spinning toy the combination of: an elongate tapered wing; first counterweighting means counterweighting said wing toward the narrower end thereof; second counterweighting means forwardly of the aerodynamic center of said wing counterweighting said wing toward the leading edge thereof; at least one stabilizing fin fixed substantially normal to the plane of said wing and positioned between the aerodynamic center of said wing and the center of gravity of said toy combination; the said fin being located on the maximum wing area side of and substantially in alignment with the said center of gravityof said toy combination for stabilizing said toy in attitude during ascent yanaerodynamic trimming means on said wing rearwardl y of the said aerodynamic center for accelerating inducement of autorotation and sustaining autorotation ofsaid toy during descent; and hooklike engagement means on said toy for engagement with a launching device.

3. In an' aerial spinning toy the combination of: an elongated wing; a boom member contiguous with said wing and extending from one end thereof; first counterweighting means counterweighting said toy combination toward the boom end thereof; second counterweighting means forwardly ,of the aerodynamic center of said wing counterweighting said wing toward the leading edge thereof; atleast one stabilizing fin fixed substantially normal to the plane of said wing and positioned between the aerodynamic center of said wing and the center of gravity of said toy combination; the said fin being located on the maximum wing area side of and substantially in alignment with the center of gravity of said toy combination for stabilizing said toy in attitude during ascent; an aero dynamic trimming means associated with said Wing for accelerating inducement of autorotation and sustaining autorotation during descent; and hook-like engagement means on said boom member for engagement with a launching device.

4. In an aerial spinning toy the combination of: an elongate tapered wing; a boom member contiguous with said wing and extending from the narrower end thereof; toy counterweighting means on said boom counterweighting said toy toward the boom end thereof and shifting the center of gravity of said toy toward that end; wing counterweighting means associated with said Wing counterweighting said wing toward the leading edge thereof and shifting the center of gravity of the wing ahead of the aerodynamic center thereof; at least one stabilizing finfixed substantially normal to the plane of said wing and positioned between the aerodynamic center of said wing and the center of gravity of said toy; the said fin being located on the maximum wing area side of and substantially in alignment with the center of gravity of said toy for stabilizing said top in attitude during ascent; aerodynamic trimming means associated with said wing for accelerating inducement of autorotation and sustaining autorotation of said toy during descent; and hook-like engagement means on said boom member for engagement with a launching device.

5. The combination set forth in claim 4 in which the aerodynamic trimming means is at least a portion of the trailing edge of said wing fixedly deflected out of the plane of said wing.

6. The combination set forth claim 4 in which the aerodynamic trimming means is at least a portion of the trailing edge of said wing adjustably defiectable either upwardly or downwardly out of the plane of said wing.

References Cited in the file-of this patent UNITED STATES PATENTS

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