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Aviation lighting
1
5(50 ILLUMINATION ITEMS Journal A. I. E. E. ILLUMINATION ITEMS Submitted by The Committee on Production and Application on Light AVIATION LIGHTING BY L. C. PORTER* The American pubUc is rapidly becoming air-minded, and the result is that aviation is advancing faster than any previous method of transportation. Like all other modes of travel, if aviation is to succeed commercially, operations must extend into the night. Night flying necessitates lighted airways and lighted airports. Great progress is being made along those lines. Guided by Government practise, the art of lighting is becoming standardized very rapidly. The lighting of the airways is installed and main- tained by the Government in much the same manner that lighthouses, buoys, etc., are operated. The prin- cipal lighting unit on the airway consists of a 24-in.* rotating searchlight equipped with a 1000-watt Mazda lamp and producing a 5-deg. beam of about two million candlepower. The speed of rotation is six rev. per min. In the latest beacon an auxiliary lens is placed in the top of the beacon to produce an upward fan of light for an indication when a flier is directly above the beacon. The rotating beacons are supplemented by smaller ñxed searchUghts,-trained up and down the course, which flash the number of the beacon. They are called ''course lights.'' There are also emergency landing fields along the airways, having illuminated wind cones, obstruction and approach boundary lights. The lighting of the airports is generally a municipal job. There seem to be two general methods in vogue. One is by the use of a number of relatively small flood- lights equipped with 1500- or 3000-watt lamps. These may be either grouped or distributed along two adjacent sides of the airports. The other method is the use of one or two very high-power field floodlights. There are three types of these in use. One consists of a large Fresnel type lens equipped with a 150-ampere high- intensity arc or a 10-kw. Mazda lamp. Another type of unit that has proved very successful consists of two 10-kw. Mazda lamps backed by search- light mirrors and equipped with lenses to spread the beam into fan shape over the field. The latest unit consists of a set of parabolic cylinder reflectors equipped with a number of 3-kw. Mazda lamps. In addition to the main field floodlights, there are white boundary lights to outline the field; green lights to indicate the best direction of approach, red lights to mark obstructions, a rotating beacon and an illumi- nated wind indicator. Most fields also have floodlighted hangars, a ceiling projector and an illuminated sign. •Engineering Department, Edison Lamp Works of the General Electric Company, Harrison, N. J. The greatest hazard in flying today is fog. Many ex- travagant claims have been made on the fog penetrating ability of neon light. It is claimed to have some pecu- liar characteristic which other forms of red light do not possess. In this connection, it is interesting to note the conclusion reached by the U. S. Bureau of Standards after making a most exhaustive study of the relative merits of a neon beacon vs, a Mazda lamp equipped with a red color screen. We quote from the Technical News Bulletin of the Bureau of Standards, Nov. 1928, No. 139 as follows: 'Observations were made with the naked eye and with a photometric wedge. No differences sufficiently great to be detected by the methods used in this test were found between the visibility of light from a neon lamp and the light of the same color, candlepower, and horizontal distribution produced by an incandescent filament lamp with color screen. "With regard to the comparison of the clear incan- descent lamp and incandescent lamp with red color screen, the red filter does not increase the range under any weather conditions, but there is some evidence that the red filter does not reduce the range as much in foggy weather as it does in clear weather." A great deal of interest has arisen in air marking signs to mark the airways and name the towns. Several systems are in use, i. ., floodlighting, neon tubes, and exposed Mazda lamps. In this connection, the U. S. Department of Commerce, Airways Division, has just completed an exhaustive test on the relative legibility of various types of signs. We quote from their report. "Illumination by direct light is the most effective owing to greater brilliance and hence greater attracting power. Markings illuminated in this manner are effective at night even though the color of the charac- ters is obscured by dirt or snow. "For outlining with incandescent lamps, not less than 10-watt sign lamps should be used and they should be spaced from 8 in. apart for 6-ft. letters to 12 in. apart for 12-ft. letters or larger. Unless there is a large amount of competing light in the vicinity of the marking, the 10- watt lamps give better legibility than lamps of higher wattage. In case it is desired to use colored lamps with a brilliance corresponding to the 10-watt clear sign lamps, 25-watt lamps should be used for green and red and 50-watt lamps for blue.'' A very effective air making sign consisting of a big 100-ft. arrow made up of standard parts, has been perfected. Plans are under way to carry out a nation wide marking of the airways with signs of this type. Several good articles on aviation lighting have ap- peared in the transaction of various engineering societies, and in the technical press, going into great detail in aviation lighting. In this article we have therefore only mentioned the latest developments.
Transcript of Aviation lighting
5(50 I L L U M I N A T I O N I T E M S Journal A. I . E . E .
I L L U M I N A T I O N I T E M S Submit ted by
The Commit tee on Product ion and Application on Light
AVIATION LIGHTING
BY L . C . PORTER* The American pubUc is rapidly becoming air-minded,
and the result is that aviation is advancing faster than any previous method of transportation. Like all other modes of travel, if aviation is to succeed commercially, operations must extend into the night. Night flying necessitates lighted airways and lighted airports. Great progress is being made along those lines. Guided by Government practise, the art of lighting is becoming standardized very rapidly.
The lighting of the airways is installed and maintained by the Government in much the same manner that lighthouses, buoys, etc., are operated. The principal lighting unit on the airway consists of a 24-in.* rotating searchlight equipped with a 1000-watt Mazda lamp and producing a 5-deg. beam of about two million candlepower. The speed of rotation is six rev. per min. In the latest beacon an auxiliary lens is placed in the top of the beacon to produce an upward fan of light for an indication when a flier is directly above the beacon. The rotating beacons are supplemented by smaller ñxed searchUghts,-trained up and down the course, which flash the number of the beacon. They are called ''course lights.''
There are also emergency landing fields along the airways, having illuminated wind cones, obstruction and approach boundary lights.
The lighting of the airports is generally a municipal job. There seem to be two general methods in vogue. One is by the use of a number of relatively small floodlights equipped with 1500- or 3000-watt lamps. These may be either grouped or distributed along two adjacent sides of the airports. The other method is the use of one or two very high-power field floodlights. There are three types of these in use. One consists of a large Fresnel type lens equipped with a 150-ampere high-intensity arc or a 10-kw. Mazda lamp.
Another type of unit tha t has proved very successful consists of two 10-kw. Mazda lamps backed by searchlight mirrors and equipped with lenses to spread the beam into fan shape over the field. The latest unit consists of a set of parabolic cylinder reflectors equipped with a number of 3-kw. Mazda lamps.
In addition to the main field floodlights, there are white boundary lights to outline the field; green lights to indicate the best direction of approach, red lights to mark obstructions, a rotating beacon and an illuminated wind indicator. Most fields also have floodlighted hangars, a ceiling projector and an illuminated sign.
•Engineering Depar tment , Edison Lamp Works of the General Electric Company, Harrison, N . J .
The greatest hazard in flying today is fog. Many extravagant claims have been made on the fog penetrating ability of neon light. I t is claimed to have some peculiar characteristic which other forms of red light do not possess. In this connection, it is interesting to note the conclusion reached by the U. S. Bureau of Standards after making a most exhaustive study of the relative merits of a neon beacon vs, a Mazda lamp equipped with a red color screen. We quote from the Technical News Bulletin of the Bureau of Standards, Nov. 1928, No. 139 as follows:
'Observations were made with the naked eye and with a photometric wedge. No differences sufficiently great to be detected by the methods used in this test were found between the visibility of light from a neon lamp and the light of the same color, candlepower, and horizontal distribution produced by an incandescent filament lamp with color screen.
"With regard to the comparison of the clear incandescent lamp and incandescent lamp with red color screen, the red filter does not increase the range under any weather conditions, but there is some evidence that the red filter does not reduce the range as much in foggy weather as it does in clear weather."
A great deal of interest has arisen in air marking signs to mark the airways and name the towns. Several systems are in use, i. β . , floodlighting, neon tubes, and exposed Mazda lamps. In this connection, the U. S. Department of Commerce, Airways Division, has just completed an exhaustive test on the relative legibility of various types of signs. We quote from their report.
"Illumination by direct light is the most effective owing to greater brilliance and hence greater attracting power. Markings illuminated in this manner are effective at night even though the color of the characters is obscured by dirt or snow.
"For outlining with incandescent lamps, not less than 10-watt sign lamps should be used and they should be spaced from 8 in. apart for 6-ft. letters to 12 in. apart for 12-f t. letters or larger. Unless there is a large amount of competing light in the vicinity of the marking, the 10-watt lamps give better legibility than lamps of higher wattage. In case it is desired to use colored lamps with a brilliance corresponding to the 10-watt clear sign lamps, 25-watt lamps should be used for green and red and 50-watt lamps for blue.' '
A very effective air making sign consisting of a big 100-ft. arrow made up of standard parts, has been perfected. Plans are under way to carry out a nation wide marking of the airways with signs of this type.
Several good articles on aviation lighting have appeared in the transaction of various engineering societies, and in the technical press, going into great detail in aviation lighting. In this article we have therefore only mentioned the latest developments.
