Tethered aerodynamic balloon with integral fins

A non-rigid aerodynamic balloon having integral stabilizing tail fins is provided. The balloon is most useful in tethered applications, such as for advertising. The balloon is formed from a plurality of flexible skin-like gores which are joined together with a plurality of longitudinal seams running lengthwise of a main body of the balloon. Each gore is a continuous piece of flexible skin-like material which forms a portion of the body and a side wall of one of the stabilizing fins. The longitudinal seams join adjacent gores along outer edges of the stabilizing fins so that seams are not required to join the stabilizing fins to the main body of the balloon.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to non-rigid aerodynamic balloons and more 
particularly to non-rigid balloons which are tethered and are used for 
advertising applications. 
2. Description of the Prior Art 
Aerodynamic tethered balloons for use in advertising or scientific 
applications, for example, are generally known. Such balloons usually have 
tail fins to keep them oriented and stable in the wind. These tail fins 
are either rigid or inflatable. Rigid fins maintain their shape because of 
the presence of structural members of metal or wood which support the tail 
fin membrane which may be flat or of an airfoil shape. Rigid fins are 
generally considered to have an advantage in some sizes of tethered 
balloons because they can be designed to be stiffer and to result in less 
stability problems. Their main disadvantage is that they are usually 
heavier, causing a payload penalty in medium size balloons, and being 
altogether too heavy to be practical on small, tethered balloons. 
Inflatable fins are often desirable because of their lightness and because 
they can be readily made in airfoil shapes. A disadvantage of previous 
inflated tail fins has been the excessive amount of hand labor required to 
build and attach them, and the resulting large amount of seam area at the 
interface of the fin and the hull or main body of the balloon. This seam 
area has been notorious for leakage problems. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a aerodynamic balloon 
in which stabilizing fins are an integral portion of the balloon body so 
that seams are not required to join the tail fins to the main body of the 
balloon. 
It is another object of this invention to eliminate leakage problems at the 
interface between the fin and the main body of the balloon. 
It is another object of this invention to reduce the amount of hand labor 
required to build aerodynamic balloons. 
In the present invention, a non-rigid aerodynamic balloon suitable for 
tethering has a main body and protruding stabilizing fins. The balloon is 
formed with a plurality of gores of skin-like flexible material which are 
joined together along longitudinal seams. Each gore may have outwardly 
curved longitudinal edges and a fin side wall portion which extends from 
one of the longitudinal edges. The gores are joined together along 
longitudinal seams generally formed in the direction of a lengthwise axis 
of the balloon body and also at outer edges of the stabilizing fins. 
The present invention retains the advantage of lightweight construction for 
the fins, combined with effective streamlining, yet totally eliminates the 
most leakage prone joint. The fin surface is formed from material which is 
contiguous with the hull material. When two adjacent hull gores are 
assembled together, the fin automatically becomes a part of the assembly. 
Additional structure which may be provided are one or more ribs or baffles 
(usually flat membranes of fabric) for support of the stabilizing fins. 
One such supporting member may be positioned within a fin while the other 
may be adjacent a base of the fin within the internal portion of the 
balloon structure. This latter supporting membrane does not in fact close 
off the gas passages to the tail fins since the fins are inflated directly 
from the main body of the balloon. This supporting membrane at the base of 
the tail fin provides the continuity of structure which is found in 
previous designs as a part of the hull material itself. 
According to the invention, there are preferably no joints in the fabric at 
the base of the fin where leakage is traditionally found. The principal 
seams are then full length longitudinal seams which are much easier to 
control and less likely to leak. 
The type of material used for the skin of the balloon contributes to the 
success of this invention. Contours change quite rapidly from the 
streamlined shape of the hull where it transforms into the protruding 
fins. A high modulous, inflexible skin would wrinkle badly in the 
transition region. Preferred materials are medium to low modulous plastic 
films or coated fabrics which have a reasonable amount of elasticity. 
Typical plastic films which are well suited include vinyl and 
polyurethane, while lightweight coated nylons have been found suitable 
among the fabric materials. 
This balloon is suitable for any size of tethered aerodynamic balloon but 
it is particularly adaptable for sizes from about 1-100 cubic meters 
(35-3500 cubic feet).

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The tethered aerodynamic balloon with integral fins of this invention is 
shown generally at 10 in FIG. 1. A tethering system 9 retains the balloon 
in position above the ground. Stabilizing tail fins 11, 12 and 13 are 
preferably spaced equal distances from one another adjacent one end of the 
balloon main body or hull 14. 
Six gores 15 through 20 are attached together at longitudinal seams 21 
through 26 to form the balloon structure. A plan view of one of the gores 
16 is shown in FIG. 3. One of the longitudinal seams such as 23 is 
comprised of a body seam portion 23a, and seam portions along outer edges 
of the tail 11, specifically front tail fin seam portion 23b, top tail fin 
seam portion 23c and rear tail fin seam portion 23d. An inwardly curved 
portion 11a is positioned on each side of the tail fin 11 at the base 
thereof. Upper outwardly bending portions 11b and 11c are positioned along 
the seam 23c. A curved merging portion 11d occurs at the junction of the 
seam portion 23b and seam portion 23a. 
To prevent adjacent side walls of the tail fin 11, for example, from 
spreading, an upper fin support member 27 which may be a skin-like 
membrane or a rib, is attached between adjacent fin side walls and runs 
longitudinally generally in the direction of the lengthwise axis of the 
balloon. Similar fin support members 28 and 29 are respectively positioned 
in fins 12 and 13 as shown most clearly in FIG. 2. 
Fin base support members 30, 31 and 32 are respectively provided adjacent 
the base portions of fins 12, 11 and 13 respectively. These support 
members again are preferably skin-like membranes or ribs which are 
attached generally at the transition point between the main body of the 
balloon and the fin side walls to prevent the base portions of the side 
walls from spreading apart. 
An inflation nozzle 33 is preferably provided at an end of the balloon 
adjacent the fins and functions as an inlet for a lifting gas such as 
helium to be placed into the balloon and sealed therein by closing the 
nozzle 33. 
Referring to FIG. 3, a plan view of gore 16 is shown which has a shape 
generally defined by outwardly curved edges 34 and 35 respectively joined 
at seams 22 and 23 in the assembled balloon. At one end of the gore 16 a 
point 36 is formed where the curved edges 34 and 35 meet. Extending from 
the curved edge 35 at the other end of the gore 16 is the material 
utilized for a side wall 55 of tail fin 11. This side wall is generally of 
a trapezoidal shape defined by a curved front edge 38, a substantially 
straight edge 39 and a substantially straight rear edge 40. A portion of 
the material used to form the nozzle is shown at 37. 
Preferably the material used for the gore is a medium to low modulous 
plastic film or a coated fabric having a reasonable amount of elasticity. 
Typical plastic films include vinyl and polyurethane while lightweight 
coated nylons have been found suitable for fabrics. It is important to 
note that the gore may be formed from a single contiguous piece of 
material for both the portion of the gore used for the main body of the 
balloon and the portion of the gore used for the side wall of the fin. 
Referring again to FIG. 1, a tethering system 9 is shown particularly well 
adapted for use with the balloon of this invention. A main tether line 41 
attaches near a leading end of the balloon with a front attachment member 
43. An attitude adjusting tether 42 of somewhat less tensile strength than 
the main tether is secured to a trailing end of the balloon by a rear 
attachment member 44. 
The adjusting tether 42 is preferably arranged in a pulley system formed of 
a ring 45 adjacent the rear attachment member 44 and rings 46 and 47 
attached downwardly from the front attachment member 43 on the main tether 
41. By looping the adjusting tether through these rings to create four 
looped sections 48a, 48b, 48c and 48d, operator adjustment of the attitude 
of the balloon in flight is simplified since less pull need be exerted on 
the adjusting tether 42. 
FIG. 4 shows a detail of the attachment members 43 or 44. A T-shaped 
attachment strip 49 having a strip portion 49a and a perpendicular support 
portion 49b is attached such as by adhesive to the skin 54 of the balloon. 
Cross strips 50 and 51 are then laid across the strip portions 49a in 
perpendicular fashion. Parallel strips 52 and 53 are then arranged to 
cross over the strips 50 and 51. 
Although various minor modifications may be suggested by those skilled in 
the art, it should be understood that we wish to embody within the scope 
of the patent warranted hereon, all such embodiments as reasonably and 
properly come within the scope of our contribution to the art.