US2667351A - Nonlifting towed target glider - Google Patents

Description

1954 M. o. MCKINNEY, JR, ETAL 2,6 7

NONLIFTING TOWED TARGET GLIDER F'iled March 28, 1951 INVENTORS Mario/z O.M/\izzzzeg Jrfiy BY JO/ZIZP.

Patented Jan. 26, 1954 I i i UNITED STATE s PATENT OFFICE" NONLIFTING TOWED TARGET GLIDER Marion 0. McKinney, Jr., and John P. Campbell,

Hampton, Va.

Application March 28, 1951, Serial No. 218,058

2 Claims.

sec. 26

(Granted under Title 35%)U. S. Code (1952), I

This invention relates to airplane-shaped tow of light construction the high speed loads produce distortion of the airframe which in turn causes excessive accelerations and trim changes. If of heavy construction to withstand air loads,

trouble will be experienced in unstable lateral os- 1 cillations due to the high mass and moments of inertia.

The present invention meets the dlfficulties mentioned by removing the lift function from the wings, as it has been determined that there is no need for lift in a tow glider, and employing the wing only to make the target look like an airplane.

The objects of the invention therefore include provision of glider wings having nonlift attributes, serving primarily as a means of providing the target with the shape of an airplane, and having a configuration efiective to reduce drag at high speeds,

A further object is to provide a glider suitable for tow target uses which is stable at airplane speeds in the neighborhood of 500 miles per hour, and which at the same time simulates airplane construction. Other objects will appear on consideration of the following description of a preferred embodiment of the invention taken in conjunction with the drawings in which Fig. l is a perspective View of a glider with wings of conventional form pivoted axially ahead of the aerodynamic center;

Fig. 2 is a view of a modified non-lift wing form;

Fig. 3 is a view of the glider wing of Fig. 2 with a trailing flap;

Fig. 4 is a view of the glider wings of Fig. 3 with a swept back construction.

In Fig. 1 the tow target form is that of a conventional glider l bearing the usual fuselage II and tail fins including vertical fin l2 and stabilizer 3.

The wings l5 include right and left sections l6 and Il. Each of these sections is pivotally mounted on a rod support [8 extending laterally from the fuselage and in line with each other and is free to pivot independently or together about the spanwise axis of the wing section. The pivot rod is placed ahead of the areodynamic center alignment with thewind; also 2 of the Wing to insure a strong tendency of wing the wing is mass balanced to avoid flutten Thus the lift function of the wings is removed, dependence for stability being placed primarily on the towline and glider tails with such stability factors as the modified wings alford.

By the described modification of the Wing structure glider speeds in the neighborhood of 500 miles per hour become feasible without substantial changes in the overall construction form and weight as used in the conventional glider. At these high speeds there is satisfactory stability with marked reduction in sensitivity to trim changes and other modifying conditions.

It is pointed out that the wings are freely pivoted each entirely independently of the other, so that each wing automatically adjusts itself to the wind incidence, or the wings may be connected together for simultaneous operation. Also, as demonstrated by tests, the towline provides adequate bank stabilizations where the glider has zero lift, since the glider tends to trail below the towing airplane. It is, of course, necessary that the towline be attached to the glider ahead of and above the glider center of gravity, a value of onetenth span above, and one-half span ahead of, the center of gravity, with a five degree towline angle, giving satisfactory results.

In Fig. 2 a modified form of wing 20 is shown with the airfoil sections 2| and 22 circular in section: i. e. rods or cylinders. These airfoils are adequate for the tow function but are deficient in visibility for target purposes, a defect which may be rectified by hinging a panel or flaps 30 and 3| to the trailing edge of the airfoil sections 2! and 22 respectively, as indicated in Fig. 3, so that the flaps trail freely in the wind. The critical Mach number of a circular airfoil section wing is relatively low. Accordingly, in order to avoid undue drag at high speeds, it may be desirable to sweep back the wing as shown by Wings 40 and 4| in Fig. 4.

In all wing forms as shown in Figs. 1, 2 and 3, the nose of the wing airfoil is symmetrically contoured so that the profiles on both sides of the nose tip are similar but reversed. It is pointed out, also, that in all modifications the pitching moment or, as otherwise stated, the lift is zero.

Other modifications of the invention may be apparent to those skilled in the art and hence no limitation is intended by the specific disclosure other than may be required by the scope of claims hereto appended,

The invention described herein may be manu.

fins including stabilizers at the tail end of said fuselage,=alined rod like elements of uni-formcir cular cross-section secured to and extending transversely from said fuselage. .a ,pair .of .wing simulating flaps each pivoted freely on said elements at a respective one of 11991311 sides of said fuselage on a line intermediate the nos and-wear edges of the flap and displaced toward thefiap nose from the aerodynamic "flap 'cen'ter "whereby 15 a zero lift characteristic is attained,.the flaps having profiles symmetrically contoured on both sides of the fuselage.

2. A tow-glider comprising a fuselage, guide fins including stabilizers at the tail end of said 20 fuselage, alined support elements :secured to and extending transversely from said fuselage on" opposite sides thereof, a pair of 'viing simulating flaps each pivoted freely on one of said elements on a line intermediate the nose and rear edge of the flap and displaced toward the flap nose from the aerodynamic flap center whereby a zero lift characteristic is attained, the flaps having profiles symmetrically contoured on both sides of the fuselage.

MARIONO. MCKINNEY, JR. JOHN P. CAMPBELL.

Number Name Date 4513-;016 Love Feb. 16, 1926 1,805,927 Aldrich May 26, 1931 1,844,448 Sramek Feb. 9, 1932 1,85-7fl01l uVa-rren May 10, 1932 2,238,875 Manson Apr. 15, 1941 2,298,425 Shafier Oct, 13, 1942 12.440373? Ca-wein .May ,4, .1948 25.28268 -Dickins,on s .Qct. 31,1959

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