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16 AIRCRAFT ENGINEERING January, 1930 Intermediat e Landing Grounds at 30-Mile Intervals and Route Beacons Every Te n Miles Are the Features of American Night-Flying Airways mirror giving 2,000,000 beam c.p. An electric [Th e following extract from the Annual Report of charged up for a six months' period of operation moto r of one-sixth h.p. rotates the searchlight at the Director of Aeronautics (Mr. Clarence M . Young) withou t attention, are installed in lieu of standard to the U.S. Secretary of Commerce (Mr. R. P. electric equipment. . 6 r.p.m. Each beacon is fitted with an automatic Standar d boundary lights, installed at intervals lam p changer, and two electric lamp bulbs. In Lamont) gives details of the emergency landing of approximately 300 ft. around the perimeters of case one lamp burns out, the stand-by lamp is grounds and lighting arrangements that have been th e fields, consist of waterproof prismatic globes automaticall y placed in circuit and in focus within adopted as standard practice on the established air route s in the United States.] an d fittings mounted on iron pipe standards 30 in. a fraction of a second. Two course lights are above the ground (where snowfall of greater depth mounte d on the 'tower platform, just below each ETWEE N terminal or intermediate airports, is anticipated the height of standards is increased) searchlight, one pointing forward and one pointing intermediat e landing fields are provided at in which are installed 15-watt electric bulbs if com backward on the airway course. The course lights approximatel y 30-mile intervals. mercial current is available, or 10-watt bulbs if ar e 500-watt searchlight projectors fitted with Th e standard intermediate field in low altitudes power is provided by a local generator. An under special cylindro-spherical mirrors and 18-in. doublet provides two landing strips or runwavs of a length ground parkway cable carries the current to the lenses, giving a beam of 15 deg . horizontal and 8 deg. of 2,000 ft. and width of 600 ft., approximately at boundar y lights. vertical spread, wit h a beam candlepower of 100,000 righ t angles to each other, with one strip lying in when fitted with lighthouse red or green lenses. th e direction of the prevailing wind. Such a field Red lenses are used a t beacon sites and green lenses Runway Lighting ha s an area of 47 acres. In the hieher altitudes a t intermediate landing fields. Each course light, Rang e lights, installed in the boundary system (above 4,000 ft.) the standard length for landing in alternation (while the main beam of the beacon an d similar in all respects to boundary lights, except strip s is 2,500 to 3,000 ft. Landing strips may is swinging through the opposite 180 deg. of are), tha t the wattag e of the bulbs is increased by 10, and form a T, L, or + , and the inner angles at the flashes its code signal, which corresponds to its tha t the clear globes are replaced by green globes, junction s of the strips are usually bevelled off to numbe r on the airway. Code signals run from are placed at opposite ends of the principal runways provide additional diagonal landing space for use 0 to 9 and then recommence. The pilot must know t o aid pilots in making landings. Two such range unde r conditions of strong cross winds. In many on which 100-mile section of airway he is flying in lights are used a t each end of th e best or prevailing- cases it is possible to secure triangular or square order to positively identify the site. wind runway, and single lights mark the centre line fields giving the desired runway lengths in all Th e beacon is mounted on a skeleton steel tower, of th e other runway. directions. In rough country it is often possible • th e standard height of which is 51 ft. Towers of Obstruction s a t the ends of landing strips or run to secure only one landing strip, in which case an standar d construction are, however, available in ways over which approaches or take-offs must be attemp t is made to increase the width of such a 20, 62, 75, and 87-ft. heights for use where condi mad e are marked in all cases by red lights at the "2-wa y field" sufficiently to permit landing tions indicate desirability of heights other than height s of such obstructions, Obstruction lights diagonally into strong cross winds. 51 ft. At the top of each tower is constructed a 6-ft. hav e 25-watt electric bulbs in lighthouse red globes. squar e platform with guard railing, providing an Where only a lew isolated obstruction lights are Th e Average Cost opportunit y for airway mechanicians to work on necessary, connection is made with the boundary Fields are licensed lor occupation for periods of th e lights with case and safety. light circuit. Where obstructions are in th e nature 5 to 10 years, with occupation for an indefinite of pole lines, or lines of trees, separate overhead period beyond this ter m subject to terminatio n upon electrical circuits are sometimes provided. Obstruc Directional Arrows Provided six months' notice by either party. The average tions along the sides of runways, where the widths cost: is $4·87 (£1) per acre per annum throughout On the ground, at each tower base, is constructed, of runways do not permit of landing or taking off th e United States. Beacon sites are similarly in concrete, a directional arrow 54 ft. in length, across them, are marked by red obstruction lights licensed, the average cost being $3·37 (13s. 6d.) which points to the next higher numbered beacon. a t obstruction height if isolated, or by obstruction pe r site per annum. Owing to the constantly Th e tower rises in the centre of the arrow. The lights at obstruction heights at the extremities of increasing public interest in air transportation, it arrow surface is painted black on the rectangular a line of obstructions, supplemented by red lights ha s been found possible to establish many inter feather end. At all fields an d a t beacons where local in the boundary light system between the ex mediat e fields on a co-operative basis, whereby the generatin g sets are required, a small power house, tremities . cit y or town at which the field is located, or some 10 by 14 ft , forms the feather end of the arrow. Desert fields are boundry lighted by special civic or commercial organisation of the city, rents A t fields which do not require local generators the acetylen e blinkers flashing one hundred times per or purchases the field and licenses it to the depart houses provide storage facilities for emergency minute , established at the corners of the fields and men t at a reduced or nominal consideration, or equipment . th e centres of long sides. Range lights, obstruction conditions the field licensed directly from the owner Gasoline engine-driven electric-generating sets, lights, and illuminated wind indicators cannot be by th e department, or both . A large portion of the where required, are furnished in duplicate, with a provided, but in such cases all obstructions have intermediat e fields established during the past year thermostati c relay control which will automatically been removed. have been established co-operatively with consider sto p the operating generator if it becomes too hot Illuminate d wind indicators are supported on able saving in expense to the Government. and will start the stand-by generator. Generators bracket s attached to the beacon towers. A con Intermediat e fields have been marked by 50-ft. ma y thus alternate automatically throughout a ventiona l wind cone or sock, 8 ft. long, 18 in. in (diameter) white circles at the intersections of the night. diamete r at the mouth, and 8 in. in diameter at runwa y centre lines, with white panels 20 ft. long Astronomic time clocks are installed at all th e opposite end, of porous weave, is coloured an d 2 ft. wide extending from the outside of the beacons connected with commercial power. These chrome yellow. A 150-watt electrical lamp is circle along the runway centre lines to indicate clocks switch on the current a t sunset and switch installed at the mouth, with a chromium-plated th e landing directions. It is proposed to increase i t off at sunrise. reflector which directs the entire output of light th e size of these markers to a diameter of 100 ft. Ther e is under service test a clock designed to int o the sock. A skeleton metal framework for the circle with a 4-ft. band and to a length of operat e on the direct current produced by the extendin g inside for a distance of 4 ft. holds this 100 ft. and widt h 4 ft. for the runway markers. The gasoline-engine-driven generators, and automatically portio n of the sock open and horizontal to increase circle and panels are constructed of crushed rock star t and stop these at the proper time, which, if th e effectiveness of the lighting. This indicator tampe d flush with th e field surface and whitewashed. th e test is successful, will permit full automatic shows wind direction at a wind velocity of 5 m.p.h . Th e boundaries of th e fields are marked by chrome operation of all electric installations. A t greater velocities the sock inflates and rises yellow sheet metal cones, 30 in. in diameter and Topographic considerations, in some instances, proportionately , reaching an angle of 7 deg. below 24 in. in height, installed immediately below the require closer spacing of lights and lighting of th e horizontal at a wind speed of 30 m.p.h. boundar y lights and attached to the boundary light hazard s t o ai r navigation, such as mountains, buttes standards . It is propose d to augmen t this boundary or canyon walls. In desert regions it has in many markin g by installing 70-ft. sections of painted 263 Intermediate Fields cases been found impracticable to install electric fence at each angle in the field boundary, and at A t the close of the fiscal year, June 30, 1929, 263 beacons, due to the lack of possible caretakers and 600-ft. intervals on long straight sides. th e difficulty of supplying local generators with intermediat e fields, equipped as described, were gasoline and oil. Th e lighting of intermediate fields comprises a being maintained by the airways division. The beacon, course lights, boundary lights, range lights, averag e cost of the lighting installation is approxi For use as auxiliary lights, or in lieu of standard obstruction lights, and illuminated wind indicator. matel y $5,000 per field. beacons at standard spacings, the airways division A standard 24-in. revolving beacon is provided at Airway beacons have been established a t approxi has designed and installed other types of beacons. each field, with the exception that in mountainous mat e 10-mile intervals from airport to airport on all Dioptric lanterns of 300 and 375 mm. diameter territory , where fields he off the air line marked lighted airways. Every third beacon is on an inter hav e been used with single acetylene burners, with by beacons or in valleys at irregular intervals mediat e field, according to standard practice. clusters of three acetylene burners, and with 500- between beacon sites, electric blinkers of lower Alteration s of the direction of airway courses wat t electric lamps. Another standard unit is a candlepower are provided ; and in desert or generally occur at fields, and the beacons between double-ended range lantern fitted with two 18-in. uninhabite d regions, where commercial electricity fields are established as near as possible on the air double t lenses similar to the course light lenses is not available, nor supplies of gasoline and oil, line from field to field. using a double acetylene burner light source. and attendants to operate local electric generators Th e standard beacon consists of a 1,000-watt Ther e were 1,399 beacons of all types in operation cannot be had, acetylene beacons, which may be searchlight fitted with a 24-in. precision parabolic a t the close of the fiscal year 1929.
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Jan 1, 1930
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