Beacon Stations For Night Flying

Beacon stations were developed for night and poor visibility flying conditions.  They are sites along an airway that consisted of a rotating navigational beacon. Most were placed on a skeleton tower approximately 50 feet in height and powered by a generator, gas or local power and used by air mail pilots for night flying. 

In December of 1926 a day mark consisting of a directional arrow was added to the sites.  This directional arrow pointed to the next higher numbered beacon station site. The first concrete arrows were whitewashed. The control shed roof was painted white on the right side of the gabled ridge and red on the left.  Black beacon numbers were painted on the white side of the shed roof, and white route numbers were painted on the red side of the shed roof.

From 1926 to 1932 most of the directional arrows were 57 feet in length, made from concrete and placed under the beacon.  A control shed was placed on the feather end of the arrow and the site number was painted on the roof of the shed to let the pilot know where they were.  If the site was powered by local power, the site number was painted directly on the shaft end of the arrow.

About 1932 they started making raised metal arrows on each end of the skeleton tower pointing to the next higher beacon number.

3 types of beacons used on the Transcontinental Airway between 1923 and 1926.

When were the Concrete arrows placed across America and what was their purpose? 

Different sources attribute them to the Post Office, but it was the Airways Division of the Lighthouse Bureau under the direction of the Post Office that created the beacon stations with the concrete arrows at the base of the towers.

The following article in the April 1927 Aero Digest shows a diagram of the arrow and explains that they were being place on Contract Air Mail Routes 1, 2, and 3.

Contract Air Mail Route #1 is the New York-Boston airway.

Contract made 7th day of October 1925 to Colonial Air Lines (Inc.); Route: Boston, Mass., via Hartford, Conn., to New York, N.Y. and return.

Service was inaugurated on this route July 1, 1926, by Colonial Air Transport, Inc.

Airway Bulletin No. 25, May 1, 1927, described the New York-Boston Airway (NY-B)-220 miles

Contract Air Mail Route # 2 is the St. Louis-Chicago airway.

Contract made 7th day of October 1925 to Robertson Aircraft Corporation; Route: Chicago, Illinois, by Springfield, Illinois to St. Louis, Missouri and Return.

Night Air Mail flights began on January 14, 1927.

Airway Bulletin No. 154, August 16, 1927, described the St. Louis-Chicago Airway (SL-C)-277 miles

Contract Air Mail Route #3 is the Dallas-Chicago airway.

Contract made May 12, 1926: National Air Transport Inc. Route: Chicago IL, Moline IL, Saint Joseph MO, Kansas City MO, Wichita KS, Oklahoma City OK, Fort Worth TX, Dallas TX and Return.

Night Air Mail flights began on February 1, 1928

On February 1, 1928 the National Air Transport started operation on their straight night schedule leaving Chicago at 8:00 P. M. and arriving at Dallas at 8:33 the following morning.  Planes now leave Dallas at 6:57 P.M. and arrive at Chicago at 7:30 A.M.  This revised schedule allows mail to be delivered the following morning which is approximately the same service which can be secured from mail posted in the same city.  
Domestic Air News Vol. 2, No.3, Serial No. 23, page 24, February 15, 1928, Stanford University Green Library, basement stack W-158; C23.9:6-32

Dallas-Kansas City Airway (D-KC) 995 miles, in 3 airway bulletins

Airway Bulletin No. 158, August 16, 1927 described the Dallas-Oklahoma City section, 210 miles

Airway Bulletin No. 159, August 16, 1927 described the Oklahoma City-Wichita section, 159 miles

Airway Bulletin No. 163, August 16, 1927 described the Wichita-Kansas City section, 173 Miles

 

Link to pdf download that contains this aritcle from: Aero Digest Vol. , page 322, April 1927

Diagram of a Concrete Arrow

Click on this link to see the diagram design

Great Arrow Chosen As Best Air Marker

J.M. Knight of Severy, Kansas, was second in the contest; A. C. Blonger, bureau of highways, Idaho and H. Don Snodgrass of Jenks, Oklahoma, led for third.

The winning designs and those submitted by F. W. (Woody) Hockaday of Wichita, whose system of highway markers made him nationally known, will be sent to Washington for consideration by the Aeronautical Division of the Department of Commerce.

William P. MacCracken, Jr. assistant secretary of commerce for aeronautics told the conference his department would assume responsibility for working out signals to be used on the airways of the nation.

 Clipped from The Hutchinson News,  12 May 1928, Sat,  Page 5

Airway Beacon Station Components

SEVENTEENTH ANNUAL REPORT, OF THE, SECRETARY OF COMMERCE, 1929

Pages 31-35

Airways are designated by the first letters of their terminal cities, thus, 0-C for Omaha to Chicago, LA-SF for Los Angeles to San Francisco. All field and standard beacon sites are known by numbers which, by the addition of zero, indicate their approximate mileage on the airway; thus, a. field 32 miles from the starting point of an airway is No. 3; a beacon 585 miles from the starting point is No. 58. Beacons other than standard are given numbers corresponding exactly to their mileage.

At the close of the fiscal year 1929, 13 experienced airplane pilots, 10 civil engineers, and 5 airplanes were assigned to the survey of airways. Four electrical and structural engineers and 18 inspectors of airways construction, all of them with extensive aeronautical experience, were engaged in the establishment of lighting equipment.

INTERMEDIATE FIELDS

The standard intermediate field in low altitudes provides two landing strips or runways of a length of 2,000 feet and width of 600 feet, approximately at right angles to each other, with one strip lying in the direction of the prevailing wind. Such a field has an area of 47 acres. In the higher altitudes (above 4,000 feet) the standard length for landing strips is 2,500 to 3,000 feet. Landing strips may form a T, L, or +, and the inner angles at the junctions of the strips are usually beveled off to provide additional diagonal landing space for use under conditions of strong cross winds. In many cases it is possible to secure triangular or square fields giving the desired runway lengths in all directions. In rough country it is often possible to secure only one landing strip, in which case an attempt is made to increase the width of such a “2-way field" sufficiently to permit landing diagonally into strong cross winds.

The field surfaces should be fairly level, and when not, level must be free from sharp breaks in grade, and well drained, naturally or by artificial methods.

Fields are licensed for occupation for periods of 5 to 10 years, with occupation for an indefinite period beyond this term subject to termination upon six months' notice by either party. The average cost is $4.87 per acre per annum throughout the United States. Beacon sites are similarly licensed, the average cost being $3.37 per site per annum.  Owing to the constantly increasing public interest in air transportation, it has been found possible to establish many intermediate fields on a cooperative basis, whereby the city or town at which the field is located, or some civic or commercial organization of the city, rents or purchases the field and licenses it to the department at a reduced or nominal consideration, or conditions the field licensed directly from the owner by the department, or both.  A large portion of the intermediate fields established during the past year have been established cooperatively with considerable saving in expense to the Government.

INTERMEDIATE FIELD MARKING AND LIGHTING

Intermediate fields have been marked by 50-foot (diameter) white circles at the intersections of the runway center lines, with white panels 20 feet long and 2 feet wide extending from the outside of the circle along the runway center lines to indicate the landing directions. It is proposed to increase the size of these markers to a diameter of 100 feet for the circle with a 4-foot band and to a length of 100 feet and width 4 feet for the runway markers. The circle and panels are constructed of crushed rock tamped Bush with the field surface and whitewashed. The boundaries of the fields are marked by chrome yellow sheet metal cones 30 inches in diameter and 24 inches in height, installed immediately below the boundary lights and attached to the boundary light standards. It is proposed to augment this boundary marking by installing 70-foot sections of painted fence at each angle in the field boundary and at 600-foot intervals on long straight sides.

The lighting of intermediate fields comprises a beacon, course lights, boundary lights, range lights, obstruction lights, and Illuminated wind indicator. A standard 24-inch revolving beacon is provided at each field, with the exception that in mountainous territory, where fields lie off the air line marked by beacons or in valleys at irregular intervals between beacon sites, electric blinkers of lower candlepower are provided; and in desert or uninhabited regions, where commercial electricity is not available, nor supplies of gasoline and oil, and attendants to operate local electric generators can not be had, acetylene beacons, which may be charged up for a 6 months' period of operation without attention, are installed in lieu of standard electric equipment.

Standard boundary lights, installed at intervals of approximately 300 feet around the perimeters of the fields, consist of waterproof prismatic globes an fittings mounted on iron pipe standards 30 inches above the ground (where snowfall of greater depth is anticipated the height of standards is increased), in which are installed 15-watt electric bulbs if commercial current is available, or 10-watt bulbs if power is provided by a local generator. An underground parkway cable carries the current to the boundary lights.

Range lights, installed in the boundary system and similar in all respects to boundary lights, except that the wattage of the bulbs is increased by 10, and that the clear globes are replaced by green globes, are placed at opposite ends of the principal runways to aid pilots in making landings. Two such range lights are used at each end of the best or prevailing-wind runway, and single lights mark the center line of the other runway.

Obstructions at the ends of landing strips or runways over which approaches, or take-offs must be made are marked in all cases by red lights at the heights of such obstructions. Obstruction lights have 25-watt electric bulbs in lighthouse red globes. Where only a few, isolated obstruction lights are necessary connection is made with the boundary light circuit. Where obstructions are in the nature of pole lines, or lines of trees, separate overhead electrical circuits are sometimes provided. Obstructions along the sides of runways, where the widths of runways do not permit of landing or taking off across them, are marked by red obstruction lights at obstruction height if isolated, or by obstruction lights at obstruction heights at the extremities of a line of obstructions, supplemented by red lights in the boundary light system between the extremities.
Desert fields are boundary lighted by special acetylene blinkers flashing one hundred times per minute, established at the corners of the fields and the centers of long sides.  Range lights, obstruction lights, and illuminated wind indicators can not be provided, but in such cases all obstructions have been removed.

Illuminated wind indicators are supported on brackets attached to the beacon towers. A conventional wind cone or sock 8 feet long, 18 inches in diameter at the mouth, and 8 inches in diameter at the opposite end, of porous weave, is colored chrome yellow. A 150-watt electrical lamp is installed at the mouth with a chromium plated reflector which directs the entire output of light into the sock. A skeleton metal framework extending inside for a distance of 4 feet holds this portion of the sock open and horizontal to increase the effectiveness of the lighting. This indicator shows wind direction at a wind velocity of 5 miles per hour. At greater velocities the sock inflates and rises proportionately, reaching an angle of 7° below the horizontal at a wind speed of 30 miles per hour.

At the close of the fiscal year 1929, 263 intermediate fields, equipped as described, were being maintained by the airways division. The average cost of the lighting installation is approximately $5,000 per field.

BEACONS

Airway beacons have been established at approximate 10-mile intervals from airport to airport on all lighted airways. Every third beacon is on an intermediate field, according to standard practice. Alterations of the direction of airway courses generally occur, at fields, and the beacons between fields are established as near as possible on the air line from field to field.

The standard beacon consists of a 1,000-watt searchlight fitted with a 24-inch precision parabolic mirror giving 2,000,000 beam candlepower. An electric motor of one-sixth horsepower rotates the searchlight at six revolutions per minute. Each beacon is fitted with an automatic lamp changer and two electric lamp bulbs. In case one lamp burns out, the stand-by lamp is automatically placed in circuit and in focus within a fraction of a second. Two course lights are mounted on the tower platform just below each searchlight, one pointing forward and one pointing backward on the airway course. The course lights are 500-watt searchlight projectors fitted with special cylindro-spherical mirrors and 18-inch doublet lenses, giving a beam of 15° horizontal and 8° vertical spread with a beam candlepower of 100,000 when fitted with lighthouse red or green lenses. Red lenses are used at beacon sites and green lenses at intermediate landing fields. Each course light, in alternation (while the main beam of the beacon is swinging through the opposite 180° of arc), flashes its code signal, which corresponds to its number on the airway. Code signals run from 0 to 9 and then recommence.  The pilot must know on which 100-mile section of airway he is flying in order to positively identify the site.

The beacon is mounted on a skeleton steel tower, the standard height of which is 51 feet. Towers of standard construction are, however, available in 20, 62, 75, and 87 foot heights for use where conditions indicate desirability of heights other than 51 feet. At the top of each tower is constructed a 6-foot square platform. with guard railing, providing an opportunity for airway mechanicians to work on the lights with ease and safety.

On the ground at each tower base is constructed in concrete a directional arrow 54 feet in length which points to the next higher numbered beacon. The tower rises in the center of the arrow. The arrow surface is painted black on the rectangular feather end. At all fields and at beacons where local generating sets are required a small powerhouse 10 by 14 feet forms the feather end of the arrow. At fields which do not require local generators the houses provide storage facilities for emergency equipment.  

Gasoline engine-driven electric-generating sets, where required, are furnished in duplicate, with a thermostatic relay control which will automatically stop the operating generator if it becomes too hot and will start the stand-by generator. Generators may thus alternate automatically throughout a night.

Astronomic time clocks are installed at all beacons connected with commercial power. These clocks switch on the current at sunset and switch it off at sunrise.

There is under service test a clock designed to operate on the direct current produced by the gasoline-engine-driven generators and automatically start and stop these at the proper time, which, if the test is successful, will permit full, automatic operation of all electric installations.

Topographic considerations, in some instances, require closer spacing of lights and lighting of hazards to air navigation, such as mountains, buttes, or canyon walls. In desert regions it has in many cases been found impracticable to install electric beacons, due to the lack of possible caretakers and the difficulty of supplying local generators with gasoline and oil.

For use as auxiliary lights, or in lieu of standard beacons at standard spacings, the airways division has designed and installed other types of beacons which work effectively. Dioptric lanterns of 300 and 375 millimeters diameter have been used with single acetylene burners, with clusters of three acetylene burners, and with 500-watt electric lamps. Another standard unit is a double-ended range lantern fitted with two 18-inch doublet lenses similar to the course light lenses using a double acetylene burner light source. When such units are used in lieu of standard beacons to mark the airway center line the standard spacing is reduced to 3 ½ miles, by which arrangement the lower candlepower is offset by the shorter spacing, resulting in practically equivalent effectiveness.

How Were Beacons Powered

There were 4 methods of powering beacon stations (many sites had batteries as a backup in case of power failure).

1. Commercial Power (example from Salt Lake-Great Falls airway, site No. 24, Department of Commerce Intermediate Landing Field, Dubois Airport).

2. Generator Plants (examples are from the Cibola County Historical Society air history museum and interpretive site at the Grants-Milan Airport.)

1929 Westinghouse generating equipment is from page 559 in the 1929 issue of The Aircraft Handbook.

3. Acetylene Gas with Sun Valve

This gas type beacon was used starting in 1924 and placed 3 miles apart along the Cheyenne-Chicago portion of the Transcontinental Airway. from the Medicine Bow Museum.	This is an example of a gas acetylene beacon station located on the San Francisco-Salt Lake Airway, site No. 50A Hardy Creek. The gas tubing as been removed and only a little evidence of it remains inside the shed.

Polkinghorne Spring beacon is a fine example of an Acetylene Gas Beacon

4. Windmills

1927 photo from: "Airports and Airways-Cost Operation and Maintenance" by Donald Duke

Beacon Stations That Still Exist

The following have an arrow, beacon, and generator shed:

18_15 SF-SL Donner
39.321803, -120.336218

The following have an arrow and generator shed:

33_11 ELP-FTW Delaware Springs / Guadalupe DOCILF
GPS: 31.853277, -104.549017

The following have an arrow, beacon, and radio station

The following are recreations at Museums:

Oregon Aviation Historical Society
arrow & beacon 2/3 original size
08_44B SF-S Cottage Grove
GPS: 43.802052, -123.038914

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