-NRLF B ^ am sat , No. 1794 DESCRIPTION OF THE WIND COMPONENT INDICATOR MECHANICAL FEATURES, METHODS OF ASSEMBLING AND DISMOUNTING, AND RULES GOVERNING ITS CARE AND PRESERVATION IN SERVICE {ONE PLATE) JULY 15, 1906 REVISED MARCH 23, 1908 WASHINGTON GOVERNMENT PRINTING OFFICE 1917 No. 1794 DESCRIPTION OF THE WIND COMPONENT INDICATOR MECHANICAL FEATURES, METHODS OF ASSEMBLING AND DISMOUNTING, AND RULES GOVERNING ITS CARE AND PRESERVATION IN SERVICE {ONE PLATE) 1 1, t. O^A VI JULY 15, 1906 REVISED MARCH 23, 1903 WASHINGTON GOVERNMENT PRINTING OFFICE 1917 \V1 Wak Department, Office of the Chief of Ordnance, Washington, May 23, 1912. This manual is published for the information and government of the Regular Army and Organized Militia of the United States. By order of the Secretary of War : Williaai Ckoziek, Brigadier General, Chief of Ordnance. 10048—17 (3) 3G52r>l THE WIND COMPONENT INDICATOR. DESCRIPTION. 1. The wind component indicator consists of a dial (2F). for read- ing- range and deflection wind components. It is made of bronze, and on its face are engraved reference numbers for range and deflection components. The lines on the face of the dial are alternately heavy and light; the heavy lines passing at right angles through the center of the dial (2F) are the axes of the dial. The range component ref- erence numbers are engraved along the vertical axis, and the deflection component reference numbers are engraved along the horizontal axis. Each heavy line passes through a reference number, the value of which is some multiple of 10. Each light line passes through a refer- ence number the value of which is some odd multiple of 5. The smallest reference number used with the scale is 0, the largest 100. As shown on the plate, these reference numbers read from on the left to 100 on the right, and from at the bottom to 100 at the top, with 50 in the center. 2. The dial is intended to be held in a vertical position by means of the bracket (2S), of bronze, which is fastened to the back of the dial in such manner that the dial itself will not turn, and hence the figures on it will always be right side up. 3. Around the dial is a wind azimuth ring (2D), of bronze, gradu- ated and numbered clockwise every 5 degrees, and movable about the dial; the dial and the wind azimuth ring are secured together by an undercut seat in the dial, a projecting annular ring in the wind azi- muth ring, three clamp plates (2T), and the clamping and guide plate (2K), in such manner that, although allowing relative angular mo- tion between the parts, they can not be dismounted without removing the screws holding the clamp plates and the clamping and guide pLate to the dial. At the bottom of the dial an azimuth pointer (2M) is attached. By moving the wind azimuth ring, which has a knurled edge for convenience in handling and setting, to any required degree as indicated on the dial by the azimuth pointer, it may be clam-ped securely in place for the desired setting by means of the dial clamp- ing screw (2N). 4. Embracing both the dial and the wind azimuth ring and ro- tating about an axle at the back of dial is the target arm (2H), of bronze, beirl fo alicyr it to pass ove)- the dial clamping screw. The azimuth index (2L) is screwed to one end of the target arm and the target-arm scale (2J), of bronze, to the other. The latter is secured to the center of the dial from the front by the pivot screw (•2A). One of the clamping screws (2P), serves to clamp the end of the tar- get arm, to which azimuth index is secured, in any desired position about the wind azimuth ring. The other clamps the pointer (2Q), of forged steel, which slides through a islot in a projecting lug near the central end of the target-arm scale. By relieving the clamping screw the pointer may be set for any velocity of wind from to 50 miles per hour, as indicated on the targ^-arm scale. 5. All exposed surfaces not subject to sliding friction are sand- blasted. Figures, letters, and graduations are blackened. The place of manufacture, date, serial number, and initials of the inspector are engraved on the face of the dial. CARE AND USE. 6. The instrunient should be kept clean and free from dust. Sur- faces subject to sliding friction should be oiled when necessary with clock oil. 7. The instrument is to be suspended from the ceiling of the chart room immediately over the plotting board and facing the range and deflection boards, so that the operators of these boards can readily see the range and deflection components without leaving their stations. In using the instrument, the operator first sets the pointer to the velocity of the wind, and the wind azimuth ring to the azimuth of the wind as obtained from the meterological station. He then keeps the target arm set to the azimuth of the target, as indicated by the gun arm of the plotting board, moving the target arm as the target moves. Should the wind change in velocity or direction, he makes the neces- sary changes in the position of the pointer or the wind azimuth ring. The sharp end of the pointer, extending over the dial, indicates at once the proper deflection and range components. War Department, Office of the Chief of Ordnance, Washington, May 23, 1912. July 15, 1906. Revised March 23, 1908. Form No. 1794. Ed. Aug. 27-17—1,000. o furt 10048- 10048 — 17. (Face page 6.) .^•>^.C' <'v ..■'"^' U.C. 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