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Publication numberUS1664170 A
Publication typeGrant
Publication dateMar 27, 1928
Filing dateApr 28, 1927
Priority dateApr 28, 1927
Publication numberUS 1664170 A, US 1664170A, US-A-1664170, US1664170 A, US1664170A
InventorsHendry William F
Original AssigneeManhattan Electrical Supply Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Aeroplane guiding light
US 1664170 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

March 27, 1928. 1,664,170

' w. F. HENDRY AEROPLANE GUIDING LIGHT Filed April 28. 1927 In mentor Attorney Patented Mar. 27,1928.




Application filed April 28; 1927. Serial No. 187,295.

This invention relates to light beacons and relates more particularly to electric light beacon systems for guiding aeroplanes.

An object of my invention is the provision of an aeroplane light beacon having a distinguishing characteristic which can readily of the light emitted by the beacon.

, providing a light source which is periodi More specifically my'invention consists in cally extinguished and in providing on the aeroplane means for detecting the frequency of the light fluctuations. -The light source preferably consistsof a gas discharge tube of the type comprising a transparent or translucent envelope enclosing two electrodes and a filling of rare gas such as neon or helium, under low preure. For best results the tube should be of the rectifying type such, for example, as a tube containing electrodes of unequal. size, but may be of any well-known type. The means for detecting the frequency of the light source preferably comprises the propeller of the aeroplane and a tachometer for registering the speed of the propeller.

An aviator using the system would view the beacon light through the aeroplane propeller and then throttle the engine until the propeller appeared to stand stationary, at .which time the propeller would be rotating at a speed in synchronism with the light frequency, or some whole multiple of that frequency. When an ordinary lighttube and source of energy is used the frequency of the light fluctuations can be determined but the propeller doe; .1013 appear so clear cut as when a rectifying light tube is used. When the latter type of tube is used, the propeller stands out much more clearly, due, probably, to the fact that the light is entirely out half of the time, rather than entirely out only a very short portion of the time. 'The same effect obtained by using a rectifying tube could also be secured by using an ordi-. nary light tube and rectifying the alternating supply current in such manner that a] half wave only would be supplied to the tube.

I have suggested the use of gas discharge light tubes as it is well known that when such tubes are used on a. circuit of varying voltage. the light produced by the tube varies with the impressed voltage, even when the voltage fluctuates at a' very high frequency. However, any other well-known source of light having the same charactertistics might be used as well.

The invention with its further objects and advantages will be more fully explained by the following description 'taken in conjunc tion with the accompanying drawings.

In Fig. 1, Which represents a beacon light system according to my invention, reference numeral 1 indicates a neon tube' light energized by an alternator 2 of a given frequency. 3 is an aeroplane having a propeller 4 through which the pilot views the neon tube beacon light 1. 5 is a tachometer which registersthespeed of propeller 4.

In'Fig. 2, 6 is an ordinary neon light tube and 2 an alternator for energizing tube 6.

The tube 6 might be one of several making up the neon tube beacon light-1.

In Fig. '3 isillustrated another form of light frequency detecting means. In this figure 7 is a disc having a cut-out portion 8. The disc 7 is'mounted on a suitable hearing and is driven from the engine shaft 11 by 'means of a chain or other gearmg.

Fig. 4 represents another form of light tube which may be used for beacon 1. ThlS tube.12 is of the same general rectifying type as is disclosed in United StQtGSPELtQIlt No. 1,628,045, except that the distance between the anodeand cathode of the tube is'made large so that sufiicient light can be produced. Tube 12 comprises an envelope 13 contalmng two electrodes 14 and 15 and a filling of rare gas at low pressure. I The operation of the system shown 1n Flg. 1 is as follows: The pilot of aeroplane 3 upon seeing, a'beacon light such as 1, views the light 1 through the revolving blades of propeller tthen varies the speed of the engine driving propeller 4 until the propeller appears to stand stationary. When this illuwould be in synchronism with the fluctuations of light '1. The pilot would then read the tachometer and from the reading obtained would know the frequency of the light fluctuations of beacon 1 and-by knowing the frequency would be able to identify the beacon light. The beacon light I might be made of one or several tubes such as shown in Figs. 2 or 4, but would preferably be made of one or more tubes such as shown in Fig. 4. With this type of tube the beacon would be shining only half of the time and hence the propeller 4 would appear more clear cut. The arrangement shown in Fig. 3 works in substantially the same manner as that shown in Fig. 1 except that instead of utilizing the propeller 4 as a synchronizing means, the aeroplane pilot would view the light through opening 10 in a plate 9, which might be mounted on some part of the aeroplane in the line of vision in the pilot. With this arrangement by properly regulating the speed of the disc driving means the pilot would be enabled either entirely to occult the light from beacon 1 or allow it to shine continuously through the coinciding open- I tively.

ings 8 and 10 of disc 7 and plate 9 respec- The speed of the engine with this arrangement would be determined by a tachometer in the same manner as shown in Fig.

' 1. The .disc 7 might be driven by means other than the aeroplane engine, such .as an electric motor, for example. In such a case the tachometer would, of course, be connected to the disc so as to register its speed.

Such an arran ement as I have disclosed would be particu arly useful where several beacon lights for various landing fields were grouped together. Each light would be operated at a dilferent frequency known to the pilot, and hence all. the pilot would have to do would be to' synchronize his indicator on I various lights successively. and thus determine the identity of the field he desired to use. L

The system might also be used on ships at sea and for other analogous uses.

It will be obvious tothose skilled in the art that the invention is capable of a wide variety of modifications and adaptations and that the present disclosure is intended merely to illustrate its nature without limiting its scope, which is definedin the appended claims.

0 What I claim is: 1. A vehicle guiding system comprising in combination, a vehicle, a light beacon, means whereby the brilliancy of said light beacon 1s per1od1cally varied at a characteristic rate,

and stroboscopic, means on the vehicle for determining the periodicity of said variation, of brilliancy.

2. A vehicle guiding system comprising in combination, a vehicle, a light beacon; means for varying the brilliancy of said beacon at quency and means inclu ing the aeroplane propeller for determining thefrequency of variation of the candle ower of said light.

5. An aeroplane guiding system comprising in combination an aeroplane, a plurality of light beacons, means for periodically varying the candle power ofeach of said beacons at a different characteristic frequency and strobo scopic means on the aeroplane fordetermining the frequency of variation of the candle power of any one of said beacons.

6. An aeroplane guiding'system comprising in combination an aeroplane, a light beacon, means for varying the brilliancy of said beacon at a given frequency, means on the aeroplane for stroboscopically determining the frequency of variation of said brilliancy and common means for ropelling the aeroplane and actuating sai second mentioned means.

7. An aeroplane guiding system comprising a neon tube light beacon energized by an alternating current source whereby the brilliancy of said light is varied at a frequency in step with that of the alternating current and means on an aeroplane including the propeller thereof, for determining the frequency of saidalternating current.

8. An aeroplane guiding s stem comprising in combination an aerop ane, a rectifying neon tube light beacon, alternating cur rent means of characteristic frequency for energizing said neon tube, aropeller for drivin the aeroplane throng which the light engine for turning said propeller, means for Y-varying thespeed of the engine and means for indicating the speed of' said engine,

from said beacon may be viewed, an

whereby the identity of said light beacon may be stroboscopically determined.

9. In an object identifying system, a plurality of spaced objects, lights on some 0 said objects, means for varying the 'brilliancy of each of said lights at a different characteristic frequency and means onanother of said objects for stroboscopically determinirig said different frequencies. f

In testimony whereof, WILLIAM F. HEN DRY has signed his name to this specification this 26th day of April, 1927,.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4912372 *Nov 28, 1988Mar 27, 1990Multi Electric Mfg. Co.Power circuit for series connected loads
US6064321 *Jan 22, 1999May 16, 2000Fort; Eldon R.Laser guidance system for propeller airplane
U.S. Classification340/953, 315/76, 340/331, 340/971, 315/246, 362/470
International ClassificationB64F1/20, B64F1/00
Cooperative ClassificationB64F1/20
European ClassificationB64F1/20