The wing-tip flare is a pyrotechnic device used for illuminating and signaling purposes. These flares are manufactured in both white and colored lights. The flare by means of suitable rigging is attached to the extremities of the wings of an aeroplane, and are ignited by means of an electric spark controlled by the aviator. This method of illumination may serve to aid the aviator in making a landing.
Fig. 193. - Rigging for wing-tip flare.
Figure 193 shows the rigging which is suspended from the tip of the plane and which holds the flare clamped firmly in place. The pivoted arm of this rigging moves in a horizontal position and is automatically brought to the vertical by means of a rubber cord, should the plane fly so low that the flare strikes the ground. A white-light flare and a red-light flare are usually used in conjunction, it being claimed that the red rays of light have a superior penetrating value in a fog or mist. The wing-tip flare is designed to burn for one minute, giving an illumination of 22,000 candlepower for the white light and from 12,000 to 15,000 candlepower for the red light.
Fig. 192. - Wing-up flare.
Referring to figure 194, it will be noted that the wing-tip flare consists of a paper case with a wood plug inserted in one end, thus making a chamber into which is loaded the illuminating composition. An electrically operated igniter with suitable wires is an essential part of this device.
Fig. 194. - Case and plug.
Fig. 195. - Sectional drawing of wing-tip flare.
4. First-flre composition.
7. Inside drumhead.
8. Outside drumhead.
9. Inside wrapper.
10. Outside wrapper.
11. Plug seal.
The wing-tip flare measures 1% inches inside diameter by 4 1/4 inches in length. The carton is made of two thicknesses of two-ply rocket hardware paper, cut 4 1/4 by 12 1/4 inches from sheets 25 by 36 inches. The smaller sheets are given a coat of paste and rolled on a mandrel, the operation being similar to that described in rolling the rocket case. When rolled this case should have an internal diameter of 1 5/8 inches. A strip of Bird's hardware paper, cut 2 1/2 by 7 inches, or a strip of Sawyer strawboard paper, 2 1/2 by 12 1/2 inches, is given a coat of paste and rolled around the carton flush with one end.
This produces a carton which has a slight shoulder, caused by the additional wrapper, at a distance of 1 3/4 inches from the. end. The smaller end of the flare is designed to fit into the metal holder of the rigging attached to the wing of the aeroplane. After the cases are rolled they are thoroughly dried.
A hardwood plug, 1 11/16 inches outside diameter and 1-inch thick, is turned and a recess, 1/2 inch in diameter and 3/16 inch deep, is cut at one end. Two holes 1/8 inch in diameter are drilled from the bottom of this recess through the plug. The channels so formed make an angle of 90°, each of them being at an angle of 45° with the short axis of the plug. These channels are bored for the purpose of allowing the threading of the electric wire used for igniting purposes.
Figure 195 shows the construction.