US1860982A - Aerial device - Google Patents

Description

J. A BINNIE AERIAL DEVICE May 31, 1932.

Filed March 27, 1931 IINVENTOR JOHN A. B/NN/E 0g 2 ATTORNEYS Patented May 31, 1932 s'ra'rss PATENT Fries JOHN A. BINNIE, OF PHILADELPHIA, PENNSYLVANIA AERIAL DEVICE Application filed March 27, 1931 Serial No. 525,649.

In its preferred form, as described in detail below, the device forms a hollow body of flexible material open at one end and having no stiffening orbracing structure except at such open end, yet such device will assume and keep its fully distended active or operative condition at relatively low speeds (say, five miles per hour) as well at the great speeds of which airplanes are capable, one of the intended uses of my invention contemplating the towing of the device by an airplane, either for target practice, or for the aerial display of advertisements painted on the outside of the device. Notwithstanding the absence of any internal bracing, this improved device is of such strength as to withstand without tearing or bursting, the great strains to which it is subjected at high speeds. 7

Reference is to be had to the accompanying drawings which illustrate a satisfactory and preferred embodiment of my invention, Fig. 1 showing the same in side elevation, with parts in section, and Fig. 2 in front elevation, looking from the open endof the device.

The device shown in the drawings is an elongated, substantially cigar-shaped bag of circular cross section made of suitable flexible material such as muslin. This bag may be made of a plurality of strips of gores (for instance, six connected by longitudinal seams, as indicated at'a). At the wider end, the bag or body is open, the size and shape of the opening being maintained by a metal ring 10 secured to the fabric of the bag by sewing or in an other suitable manner. Except for said opening, the bag is closed, and consists of a frusto-conical portion 11, flaring away from the open end, and the closed end portion 12, which in longitudinal section is substantiallyof parabolic curvature. For the purpose of connecting the bag with the towing airplane, I provide grommets 13 on the fabric adjacentto the ring 10, at equal distances from each other, and through said grominets'and around the ring 10 I loop one end of a set of lines 14, their other ends being attached to a swivel ring 15, to which the tow-line 16 of theairplane is connected.

It will be understood that except for the metal ring 10, the bag has no bracing or stiffening members, and is perfectly flexible. hen air rushes into the open end of the bag, as it will when the bag is towed behind an airplane, it will distend and, as it were, in-

flate the bag so as to keep it substantially rigid and maintain it in the shape illustrated by Fig. 1. The bag will therefore present an unvarying appearance, which is of importance when it is to be used as a target, or as a background or carrier for an advertisement painted on its outer surface.

In the practical use of devices of the character described, considerable difficulty was experienced at first on account of the special qualities required of the bag or envelope to enable it to perform equally well at high and at low speeds. When the envelope is of relatively great porosity, the bag will remain limp at low speeds, and fail to assume its operative, distended shape. If, however, the envelope has but little porosity, or practically none (for instance, when made of rubber), it will rip or burst at high speeds. The degree of porosity must be such as to permit a sufficient amount of air to pass outwardly through the fabric of the envelope at high speed, to prevent bursting of the bag, yet the air must not pass through the fabric too freely, since then the device will not operate properly at low speeds. I have found that the proper degree of porosity can be obtained, in the case of muslin or similar fabrics, by applying on the outside of the bag, a single, relatively thin coating of a suitable porosity-reducing substance. I have used a coat of pantasote for this purpose, and found it highly satisfactory.

The particular shape of the bag facilitates its proper operation and by stream line formation reduces skin friction. The application of the orosity-reducing substance on the outside 0? the envelope gives it a smoother surface than it would have otherwise and increases the durability of the device.

7 6 Various modifications may be made without departing from the nature of my invention as set forth in the appended claims.

I claim: 1. A device of the class described, com 10 prising an elongated bag open at one end and made of a porous fabric the pores of which are partly filled with a porosity-reducing substance, so as still to permit the passage of a certain amount of air through said fabric. 16 2. A device of the class described, comprising an elongated ba open at one end and made of a porous fa ric having an exterior coating of a substance which will reduce the porosity of said fabric while still 20 permitting the passage of a certain amount of air therethrough.

In testimony whereof I have hereunto set i my hand.

JOHN A. BINNIE.

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