Fin structure of balloon

A fin combined with a balloon, comprising:

• the balloon;
• a frame comprising a pair of opposite and spaced support rods having first and second ends and a cross rod connected between respective first ends of the support rods, the frame including a pair of connection members each coupling a respective first end of one of support rods with the cross rod, each connection member being formed by an angularly contoured tubular element having a reinforcing rib bridging an enclosed angle of the angular contour;
• a flexible sheet of material having first, second, and third edges respectively fixed to the pair of support rods and the cross rod, a fourth edge of the flexible sheet opposite to the third edge thereof fixed to the cross rod being devoid of support rods and spaced from the balloon, the flexible sheet having a pair of longitudinally spaced first holes formed therethrough adjacent the fourth edge;
• a pair of connectors mounted to the balloon in longitudinally spaced relationship for receiving and respectively releaseably retaining the second end of each support rod to the balloon, each connector having a pair of lugs extending therefrom, each lug having a second hole formed therethrough;
• and,
• a pair of ropes, each of the ropes being tied between a respective one of the first holes in the flexible sheet and the second holes in the lugs of a respective connector.