US2459150A - Interception trainer - Google Patents

Description

Jan. 18, 1949. c. J. CRANE ETAL INTERCEPTION TRAINER '7 Sheets-Sheet 1 Filed Feb. 26, 1940 /vo/vq A. 87-007- Ir N ' v 4&- RA EYJ Jan. 18, 1949. c. J. CRANE ETAL INTERCEPTION TRAINER '7 Shets-Sheet 3 Filed Feb. 26, 1940 GEORGE 14/7 04 LO/VAA/ CARL 714/ 704. 4.5

knr/vo/vo K drour Jan. 18, 1949. c, RANE mg 2,459,150

INTERCEPTION TRAINER Filed Feb, 26,';94o 7 Sheets-Sheet 4 Jan. 18, 1949. c. J. CRANE EIAL INTERCEPTION TRAINER Filed Feb. 26, 1940 7 Sheets-Sheet 5 /N V15 N 7'01? 5 C424 J. CRH/VE GEORGE 11/704 4on4 0,424 W/7(/LL&E Er/Mo/vo A. 670a r -x 1949- c. J. CRANE ETAL INTERCEPTIQN TRAINER 7 Sheets-Sheet 6 Filed Feb. 26,. 1940 Patented Jan. 18, 1949 INTERCEPTION TRAINER Carl J. Crane and George V. Holloman, Dayton, Carl W. Muller, Osborn, and Raymond K. Stout,

Dayton, Ohio Application February 26, 1940, Serial No. 320,880

(Granted under the act of March 3, 1833, as amended April 30, 1928; 3'70 0. G. 757) 6 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

This invention relates in general to improvements in auxiliary apparatus used in combination with aviation ground trainers and more particularly relates to a novel arrangement of transparent recorder table surfaces, one of which sur faces supports a simulated air borne or sea borne target propelled at a constant speed and having a controlled direction and another of which surfaces supports a course indicator, or recorder, controlled by the aviation ground trainer, whereby simultaneous observation of the relative position of the recorder and the target permits the solution of interception problems;

At the present time instruction in complicated aviation flight problems is given on aviation ground trainers, such as the well-known Link trainer, with a consequent reduction in actual flying time necessary to complete the course of instruction. The structure and operation ofsuch trainers is disclosed in United States Patents Nos. 1,825,462 and 2,099,857, granted to Edwin A. Link, Jr.

It is customary in the operation of aviation ground trainers to use in conjunction therewith, a course indicator, or recorder, which comprises a frame supported by a plurality of rollers, each of the rollers being rotatable about a vertical axis to cause a change in direction of rotation of the rollers. The rollers are mounted on vertical shafts, which are interconnected by gearing to a selsyn receiver mounted on the recorder frame. The selsyn receiver is electrically connected to a selsyn transmitter, driven by the trainer as it rotates about a vertical axis, so that the recorder rollers are always rotated through the same angle as the trainer and the heading of the recorder thus corresponds at any instant with the heading of the trainer. At least two of the supporting rollers of the recorder are driven by small electric motors generally of the synchronous type, so that the speed of the recorder over the map table represents to a definite scale the simulated velocity in flight of the trainer. The speed of the recorder, or course indicator is kept constant, but

may be adjusted to any desired value by changing the speed of the generator supplying current to the propulsion motors on the recorder.

Course recorders such as above described generally employ one of the supporting rollers as a marker wheel, which when inked by a felt pad,

traces the course of the recorder on the record 2 map, though the position of the marker wheel even when not inked serves as a course indicator.

For a more complete description of course recorders suitable for use with aviation ground trainers, preference may be had to United States Patent No. 1,293,747, to Hannibal C. Ford and to United States Patent No. 2,179,663, granted to Edwin A. Link, J1.

In a course of instruction on the ground trainer, it is desirable to be able to solve interception problems, for example to simulate flight intercepting another aeroplane, or water borne target, knowing the course and speed of the target under either simulated fair Weather conditions, or under simulated bad weather conditions, necessitating simulating instrument flight either in Whole or in part. A. means to render such instruction possible is provided by the invention, in which a record map table is provided with a plurality of record surfaces arranged in a rack in the form of shelves and preferably made of a transparent material such as glass, or one of the well-known transparent plastic materials. The target to be intercepted is placed one of the surfaces, which has suitable course indicia marked thereon and the target is set into motion with a velocity and under a controlled heading in accordance with the desire of the instructor and the trainer course recorder is placed in operation under the directional control of the trainer and at a velocity proportional to the simulated air velocity of the trainer and starting at a definite point and with a known. heading. The instructor then informs the student of the course and simulated velocity of the target, who then must solve the vector problem to intercept the target at the proper point. The movement of the course recorder relative to the target is at all times visible to the instructor and the record trace upon the record surfaces leaves a picture of the completeness of the problems solution. 1- simulated trainer flight may be wholly on instru ments, or may simu ate fair weather flight, the student observing the position of the course recorder relative to the target alter simulating flight for a time sufficient to bring the target into view, if the same were in actual flight, so that the resulting solution of the problem becomes apparent.

Since it is essential to take into account the effect of simulated drift, on either the air borne or water borne targets and also the effect of winds on the trainer, the invention provides a means for correctly simulating such eifects by means of a device permitting the recorder and targets to be displaced in a direction and at a velocity proportional to the effect of a simulated air current on the trainer or air borne target and to the effect of water currents on the water borne target.

Analogous to the solution of interceptionproblems is the simulation of control of trafiic of a plurality of aircraft operating at different altitudes approaching the same destination and required to proceed to a landing in accordance with their order of arrival and their respective altitudes. Such trafiic control problems may be readily solved with the trainer record table used according to the invention, by providing a separate record surface in the form of a shelf for each trainer to be operated and the instructor can then watch the respective recorders and give to each student the proper informationas to the conduct of his respective simulated flight, in the same manner that a traffic control director at a large airport conducts the safe landing of a number or" aircraft arriving at close intervals of time. It merely requires the supplying of'the proper maps and charts in order to convert from one type of problem to another.

It is an object of this invention to'provide apparatus for aviation ground training in which a multiple surface record table serves as a support for one or more simulated air borne or water borne targets, each having a controlled velocity and direction on one of said surfaces and one or more course indicators, or recorders, each directionally controlled by a respective ground trainer and operating at a velocity proportional to the simulated flight velocity of the trainer, whereby flight interception problems may be simulated.

A further object of the invention is the provision of a novel trainer table assembly comprising a plurality of superimposed spaced transparent surfaces, each surface having position indicia thereon, whereby the instantaneous relative position of a ground trainer .courseindicator and a simulated air borne or a water borne target may be observed.

Another object of the invention is the .provision of a means to cause a movement of a course indicator for an aviation ground trainer relative to its record surface, in a manner to simulate the eiTect of a wind acting on said trainer, while in simulated aircraft flight.

A further object of theinvention is the provision of a means for affecting the movement of a recorder, simulating in velocity and direction, the movement of an air borne or'water borne craft in a manner equivalent to the effect on said craft of an external force such as wind or water currents respectively.

A further object of the invention is the provision of a novel trainer table assembly permitting simultaneous operation of a plurality of aviation ground trainer recorders thereon, whereby simultaneous simulated flights of a plurality of aviation ground trainers may be directed'by an instructor.

Other objects of the invention will appear by reference to the specification and the appended drawings forming a part thereof and in which:

Fig. 1 illustrates a trainer record table having superimposed record surfaces, one of which surfaces cooperates with a simulated air or water borne target and another of said surfaces cooperates with a course recorder controlled'by 'an aviation ground trainer;

Fig. 2 illustrates anenlargedview of a, simulated water borne target, as employed in the invention;

Fig. 3 illustrates an enlarged view of the device illustrated in Fig. 2, showing the driving mechanism;

Fig. 4 is a vertical cross sectional view .of Fig. 3;

Fig. 5 illustrates a simulated water borne target similar to the device of Figs. 2, 3 and 4 modified for use with distant speed and direction controls;

Fig. 6 is a vertical-cross sectional view of Fig. 5;

:Fig. '7 illustrates the means employed fordistantlyscontrolling the speed and direction of the targets illustrated in Figs. 5 and 6;

Fig. 8 illustrates an enlarged view of a simulated air borne target employed in the invention;

Fig. .9 illustrates a vertical section of a modified trainer record table assembly permitting wind or water current drift efiects to be simulated;

Fig. 10 is a top' plan view of the-deviceofFig. 9;

Figure 11 is an illustration oftwo ofthe trainer record table devices of Figures 9'an'd lo-superimposed and used to replace the tables of the device of Figure 1.

Fig. 12 .is a top plan View illustrating an aviation ground trainer and'table array permitting traffic control problems to be solved; and

Fig. 13 is a frontelevation showing the ar rangement illustrated inF-ig.'12.

Referring to Fig. 1, the reference .numeral I generally indicates a record map table having thereon an .upper supporting surface 2 and spaced therefrom and parallel therewith, a lower supporting surface 3 arranged in theform of a shelf. The upperand lower surfaces are. preferably made of a transparentmaterial .such as glass or any of thetransparent syntheticresinous materials where it is desired to use the table for the solution of course interception problems.

The .upper and lower surfaces .2 andliare each ruled with suitable indicia i,,such aslines indicating latitude andllongitude, representing apart of the surface of .thetearth, either landior water and the indicia are ruled so as-toibeiidentical when superimposed.

An aviation ground trainerfi is placed adjacent the trainer. record. table i .and .iselectrically. conthe surface 3.

.nected through the-electric selsyn-.transmission conductorsfi to a course recorder 7,. movable over one of the record surfaces and shown, as being The recorder l is supportediby a plurality of rollers 8, one of which-serves as a marker wheel to leave an inked-trace'ofthe recorder path on the'recordsurface 53. Generally the recordersiare provided with'three rollers,"two .of whichxare drivenby small electric motors (not shown) supplied with currentvby the conductors :9. The motors drive therecorderl over the surface 3 at a'constant speed, representingto a-predetermined-scale, the simulated velocity of flight of the trainer 5. "i'he rollers '8 are mounte'd'on vertical shafts, which are interconnected by gearing with a selsyn receiver (not showmgwhich in turn is connected by'the conductors 6'to a selsyntransmitten rotated by the trainer 5 as it changes 'its heading. The directionalheading of the recorder rollers 8 are thussimultaneously rotated in step with the rotation of .the trainer and the course taken by the recorder in its movement relative to'the surface'3, is thus controlled by the heading of the trainer. '.The .construction of the recorder and its control lby the trainer,

asbefore noted, is we'll known inthe art and the shown) detail construction of the recorder and its control, therefore, has not been illustrated in the drawings.

As seen in Fig. 1, a simulated water borne target I0, is adapted to be propelled over the record surface 2 at a velocity proportional to the simulated velocity of a target vessel on the ocean and is adapted to be directionally controlled at the will of the instructor. One form of the simulated water borne target If) is illustrated in Figs. 2, 3 and 4 in which the target comprises a hull shaped casing i I, supported for movement over a record surface by two pairs of rollers l2 and I2 respectively. As seen in Fig. 2, the casing H has two manually controlled knobs thereon, the knob 33, controlling the plane of rotation of the rollers l2 and I2 and the knob 39, controlling the speed setting of a rheostat governing the speed of the driving motors. A suitable scale reading indegrees of rotation and simulated speed in knots is placed adjacent the respective knobs 33 and 39, so that their respective settings may be observed.

As seen in Figs. 3 and 4, the propelling mechanism comprises a frame [4, secured to the casing II as by bolts, the frame having enlarged bosses l5 and I5, which serve as bearings for the vertical shafts l3 and iii. The shafts l3 serve as supports for the rollers l2, which are rotatably mounted on the lower ends of the shafts. Small electric motors I6 are mounted on the shafts l3 and are rotatable therewith. The motors It may be of the well-known universal type, which can be energized from any suitable low voltage alternating or direct current source. The shafts I6, of the motors [5, pass through suitable journal openings transverse to the axis of shafts l3 and have pinion gears I! mounted on the end portions of the shafts. The pinion gears l'l mesh with idler gears l8 rotatably mounted on pivots carried. by the shafts The idler gears l8 each mesh with a driving gear l9 secured to each of the rollers 12 and rotatable therewith. The motors I6 each have secured thereto a pair of brushes and 22, which contact the respective slip rings 2| and 23 mounted on the bosses 15. The slip rings are connected'in parallelby a pair of conductors 31 to a'powe'r source (not Each motor [6, when energized from the power source, will drive a respective roller l2 through the medium of pinion gear IT, idler 7 gear 18 and driving gear 19, at a speed proportional to the motor speed. The motor speed is adjusted to give a desired speed of translation to the target If by means of a variable resistance 34, inserted in series with one of the conductors 31. The resistance 34 may be varied by rotation of the arm 35 by the shaft 35. The shaft 36 carries the manual adjustment knob 39, as seen in Fig. 2, so that the speed of the driving motors [6 may be set at any desired value by rotation of the knob 39. The motors l6 preferably are provided with built in reduction gearing, so that the normal speed of the shafts IE will be a desired small number of revolutions per minute.

Upon their upper ends, the shafts l3, each carry a gear 24, which mesh with a gear 25, rotatably -mounted on the upper end of the shaft 21, rotatably mounted in frame M. The vertical shafts l3 are rotatably mounted in the bosses I5 and the rollers l2 are rotatablymounted on pivots carried by the lower ends of the shafts I3. At their upper ends, the shafts l3 are each provided with a gear 26, meshing with the gear 25.

' The shaft 21 carries a bevel gear 28 adjacent its conductors 31.

6. lower end and the gear 28 meshes with a bevel gear 3!, mounted on the inner end of the shaft 32. The shaft 32 is suitably supported by the frame [4 and at its outer end carries the knob 33. Rotation of the knob 33 causes rotation of gears 3i and 23, shaft 2'1, gear and gears 24 and 26. Rotation of gears 24 and 26, causes the plane of rotation of rollers I2 and I2 to be rotated in equal angular increments. The knob 33 thus serves as a means to alter the heading of the target III at the will of the instructor.

A vertical shaft 29 is secured to the lower end of the shaft 2'! and is coaxial therewith. The shaft 29 terminates in a fork in which the marker roller is rotatably mounted. The roller, when inked by an ink saturated felt, will trace the recorder path on a record sheet and is rotatable in unison with the rollers 12 and I2 by the knob 33.

The target [0 is placed in operation by the instructor by aligning the target roller planes with a line on the table surface 2 and then rotating the knob 33 until the desired heading is obtained. The knob 39 is set to operate the motors H5 at the desired speed to give a velocity of translation having a definite ratio to the simulated velocity of a water borne craft and the motors are then energized by connecting the conductors 37 to the power source through a suitable switch (not shown).

Figs. 5, 6 and 7 illustrate a modified form of driving and control mechanism for the target [0, illustrated in Fig. 2, and similar parts are given the same reference numerals as in Figs. 2, 3 and 4. The construction, as seen in Figs. 5 and 6, differs from the driving mechanism illustrated in Figs. 3 and 4, in that the electric motors [6 are replaced by synchronous motors is which are adapted to run at a speed determined by the frequency of the alternating current supply for the motors, but the driving mechanism to the rollers I2 otherwise remains the same. The shaft 21 for the gear 25 is replaced by the rotor shaft 21' of a selsyn receiver 40, mounted on the recorder frame Id. The gear 25 is thus rotated in unison with the rotor of the selsyn receiver 40. The shaft 22 and marker roller 30 are mounted on the lower end of the shaft 21' of the selsyn receiver 40 in the same manner as illustrated in Figs. 3 and 4. The selsyn receiver is adapted to be connected to a selsyn transmitter by means of the conductors 4| and the motors I are adapted to be connected to a controlled frequency alternating current supply, by means of Rotation of the rotor of the selsyn receiver M3 thus controls the azimuth heading of the target ID in the same manner as the manual control knob 33 and the speed of motors I65, and hence the velocity of the target can be controlled by control of the frequency of the alternating current supply for the motors.

The distant control mechanism for controlling the selsyn receiver and the frequency of the alternating current supply for motors I65, is illustrated in Fig. '7, in which the reference numeral t2 indicates a variable speed electric motor supplied with direct current by conductors 43 and controlled by a variable resistance 44, which may nple be connected in series with the arma and field for a series wound motor, or connected in the armature circuit of a shunt wound motor. The motor 42, is connected to drive a small alternator 45, which supplies current to the conductors 3'1" at a frequency proportional to the speed of rotation of the motor instruments in bad weather.

regenerate instructor by adjustmentofthe rheostaltfld, which will control the speed ofwmdtomfl and ':'the..fr e-- :quencysof the current-generated: by.-the alternator 45, which in turn controls :the ispeedcof .i th'emyn- The motors 4:155

.chronous driving motors x1165.

ma be purchased with 'sbuilt inzgear"reductions wsimil'artoithatabove described with sreference to 1 the universal:motors-d5,xthus:permitting the tareet-t be driven at a very slow speed.

' The selsyn-receiver lli: (Figure'fi) is connected by theleads H to a :selsyn transmitter 50,?the

trot-or .of which canbe revolvedwbyithesknob l,

:so that the directional-heading.oftthectarget- I0 may be controlled by rotating the knob 5|. The stator windings of the selsyn': receiver 4lland .thefiselsyn transmitter "are supplied by a constant frequency source of alternatingcurrentnot .trol knob 5i and-the rheostatM serve tor-respec- *tlveiy maintain theiheading and :velocity: of the target as desiredby: the instructor. Themotor 1 generator set and the -.selsyn controlm-ay be placed in the cabinet indicated by the: reference character la (Fig. .1) .placed adjacent --the instructors position, on thesideof the recordttable frame.

Fig. '8' iilustrates'the simulatedfair borne target which. may be? used in interception problems ..inthe same-manner as the simulated sea borne fhe targeted has the outline. of an aeroplaneiand is supported on rollers MEI; :which target '1 d.

are :adapted to be driven and directionally 'controlled in the same manner as above "described with reference to Figshzto 7.=inclusive. -A small .c red roller is .usedas-a marker-wheel similar in -Iunction to the roller '38 of the device illustrated in Figs, .2-to -7, inclusive. Thmtargetfifi maybe manually controlled by .course: and (speed control knChSQBand-ES, in the-.samemanner -as illustratedin Figs. l 34 and 4, or the target may-be distantly controll d in theHma-nner'illustrated'in Figs. 5 to '7 .inclusive.

Aninterception problem .is solved .by .the in- -structor setting either one .or more ltargetssl-fl, or fill, into operationon .thesurface '2,..of .table I, .with a desired heading and with .a velocity proportional to the simulated .air velocity, or water velocity, or the .target craft .to be represented. Thetrainer' isthen placed inoperation Withlthe recorder l ,parallel .to the headingof. the wtrainer and th course .andsimulated yelocity v.ofthe target is giventothestudent aurally. Thecstudent must then solve a vector'problem tovobtain the .proper course .tosimulatawm .orderzto intercent the target or :60. The-instructor, beingl telephonic communication 'with the student, can at any time alter'the speedanddirection of the target and informing the student of the change, add additional elements to the problem. The simulated trainer flight maybe madeto representthe flying in fairweather, or'flying by Where the table surfaces are made of transparentmaterial, the indicia on the surfaces .2 and 3, permit the instructor to watch'all phases in the solution of the problem and the record traces left .onthe surfaces by the inked .marker wheels.,.serve..as a meansto visualize the solution ofthe problem and any errors therein caused by improper simulated "flight by the student in'the trainer.

. 78 In .;;the :solution :of interception problems as sabove Edescribed, it-is important totbe -abl'e to introduce the efi'ect of simulated Winds:acting -ron :bothathe trainer-end the isimulatednairuborne :target o'r intheeaseof-the simulated iwatertborne target, the :eiiect .tof currents or other..-.factors acausingi-drift. i-Atmeans -.-to -simulate .such air or J Mater currenteeifects is illustrated in Figs. 9 and '-l0,- :ln which t-heinumeral. liltindicates. eachoffour lfi ftubular verticali-supports; each :provided with :zrollers i i, ,pivotaliy .mountedron the lower -.ends .thereof and. adaptedrto. beiinlroliing vcontact with ..1theesurfacccofva door. The rollers I'll .mayIbe eprovid'ed:withsuitablebrake devices (not shown) y 5 T1170 lretain the supportsiin a fixed .,position .on the .floor. The supports ill! tare retained insspaced trelationsand' serve to supporti e. light. metal trans- ;verse Tframe :generally "indicated .by the numeral 12. lThelira-me 12 comprises transverse side .rails :13. and TM spacecl by. the.zcentrally-idisposed cross- .tie T15 .and the .iplatamembers 7.6 and i 71, placed 'at-lthc.respective-endscof the frame. .Thesid railsliitenninateat each end in spaced enlarged .bosses "1.8,, which. serve .as guides -in which the -yertical Ltuhular supports 7d -.are placed. .The

loosses $1.18 are-.proiri'cledwith ciamping screwslli v so...that ithe frame TZ may be a'djusted vertically ...on"thel-.supports 'fThe .crosstie" l5 isprovided with an-enlargedlbossiw -.whioh serves .as a guide land. clamping .means .for the vertical shaft 8! which-carries ai'ilange l821at1its outer end, to Jwhih is secured the 'recor'd-table'83, which may .have a transparent. recordsurface such as above described withrference'to suffaces'iZ and "-3 of the device ofFigJl. .At one end .of theiframeil'2, .a roll s'haftit' lis rotatably (mounted transverse .to the "frame". axis, bybeai'ing'bosses"85, formed inlthe "frame membersillt'an'dll. The roll shaft 84 has a worm wheelllBii and a, pulleyitl mounted thereon, adjacent the frame member "'53. The worm wheel 86 is driven'by a worm "88 mounted in suitable'bearings carried by the plate'ilt. The .worrn'fit'is driven by a reversible adjustable speed electric 'motorila, alsomounted on "theiplate I6.

*A 'fiexible endless belt idfltpasses over'th'e pulley 81 foyer an adjustable"idler'pulley '9!', onto a ifpulley 9|, secured "to .a. second roll shaft 92, mounted transversely to the frames "1 3 and "15,: in bea'ringi'besses 9'3. 'spooloi-"drumtt is secured "is secured to the'shaft 92 Archer "97' is rotatably mountedon the frames "-TS'and 14ttransversely thereof, adj a'centthe drum 95' andthe mounting made "adjustable longitudinally by 'means 'not "shown, "and a similar -roll Q 8 is'mount'ed transversly'of frames lil' andfi' l. adj acentthe drum 94. The "outerpefipheral surface of the rolls 9i" and *Ware' tangent Withthe "planeoftheupper surface "of the table; 53m "slightly "above the said "table yo-surface. -'A"transparent"endlessbelt lllil passes ioverthedrums 94 and .BE'and rollers "S'l and98 and"passes "over the surface-of the table 33 in contact therewith.

When" the motor-8 9 is energized "to rotate in "one direction, the-worm 88 'willdrive the worm gear 86, which will turn shaft 34 and pulleyt'l. The pulley. 8'!, hymeanso'f belt 90, "drives pulley -fSI "'an'clr.shaft9'2. .The'sha'fts 84 :and 92 :respecittivlymotatethe drums 94 'and'95, causing the iendlesstransparent.belt"lllll'to move in one direcitionrelative' to the'surface of tab'1ei83. Reversal ;.of"'motor 3 9' will. drivethe belt i 08. in the opposite direction. The outline. of itable 183 isshown in noneunnes .l in Fig. '10 "forosimplicity," but [it will "the evident Lthat "the ltransparent .belt' I00 may 9 move in a plane having any desired angle relative to the longitudinal axis of the table surface 83, by either rotating the table relative to the frame I2 or preferably rotating the frame 12, by means of rollers II about the axis of the vertical shaft BI relative to the table 83.

In the operation of the cross wind simulating device, the trainer recorder I, serving as. an indicator, is placed on the belt I and the belt set in motion at a velocity proportional to the velocity of the wind to be simulated and having the longitudinal axis of the belt I00, making the desired angle relative to the longitudinal axis of the table 83. The belt I00 will then bodily displace the recorder in a direction and at a velocity equivalent to the effect of a wind acting on the simulated air borne trainer. The student must then correct the heading ofthe trainer by an amount equal to the drift angle and as indicated in Fig. 10, if line B-C represents in length to a certain scale, the velocity and direction of the wind and A--C represents the true course to be traversed relative to a suitable chart placed on the record surface 83, having a heading of angle .r, then line AB, which represents the simulated air speed of the trainer, is the course which must be steered, to compensate for the effect of the wind component B-C and the trainer heading and similarly the heading of the recorder must be changed to angle y, which equals the sum of angle :r and angle z, the drift angle. No matter what the angle between the axis of the belt I00 and the longitudinal axis of the table, the effect of wind will be correctly applied to the recorder in the same manner as the wind would affect the flight of an aeroplane, simulated by the trainer 5. When employing the wind simulating device above described the position of the course indicator marker wheel relative to a suitable chart placed on the table 83 beneath the belt I00, serves to visually indicate to the instructor the position of the flight trainer in its assumed flight and the instructor gives the student the corresponding positional signal. The course indicator thus leaves no actual record on the chart of table 83.

To utilize the device of Figs. 9 and 10, in the solution of interception problems as in Fig. 1, two or more of the frame and table assemblies 'I283, are superimposed in the manner illustrated in Figure 11, parts in common with Figure 1 having the same reference numerals. If a water borne target is to be operated on the upper assembly table, its table may be rotated relative to the belt I00, so that the effect on a target I0, will simulate the effect of a water current, while the belt I00 on the lower table may be arranged to simulate the effect of a wind acting on the trainer during the interception problem. With such an arrangement the course of the target will be referred to the position indicia on the lower table surface only, the chart to be used being placed thereon. In a similar manner the effect of Wind. on both the trainer and the air borne target 60 may be simulated. The operation of the assembly of Figure 11 is otherwise identical to the operation of the device of Figure 1 described above.

It is to be understood that transparent tables 83 are not essential where continuous observation of the target and trainer recorder courses is not required and in such a case the tables may be of any desired material suitable for the intended purpose. The wind simulator as noted is generally applicable to ground trainer instruc- 10 tion and is not limited in use to interception problems.

As seen in Figs. 12 and 13, a variation of the apparatus shown in Fig. l is used to simulate air traffic control problems and the numeral fill represents a record table similar to the table I, illustrated in Fig. 1. The table I0i has a plurality of surfaces I02, I03, I04 and I05, in superimposed spaced relation and preferably made of transparent material similar to the surfaces 2 and 3, of the device of Fig. 1. The table surfaces each serve as a support for an aviation ground trainer course recorder R1, R2, R3 and R4 respectively. Each course recorder is connected by an electric conductor S1, S2, S3 or S4 respectively, to a corresponding flight trainer T1, T2, T3 or T4 respectively, to be directionally controlled thereby. The trainers are grouped around the table and each is assumed to be flying at a different altitude from the other trainers. The course recorders are placed in operation tracing the course of the simulated trainer flights, which are to end at a predetermined point common to all the trainers. The instructor has telephonic communication with each trainer and as the course recorders approach the predetermined destination, the instructor may then give individual instructions as to the conduct of the flight of each trainer, so that a simulated landing can be made by each trainer in a prescribed manner, dependent on the assumed altitude of the particular trainer. The instructor can watch all of the recorders and their positions relative to the assumed landing destination and thus has complete control over the directional information to be given in the solution of the problem.

While preferred embodiments of the invention have been illustrated in the drawings, it is ap-. parent that other modifications can be made falling within the scope of the invention as defined by the appended claims.

We claim:

1. In an aviation ground training system, an aviation ground trainer for simulating aircraft flight, a pair of superimposed reference surfaces arranged in parallel spaced relation and at least one of said surfaces being formed of a transparent material, a course indicator associated with one of said surfaces and adapted to have a translatory movement relative thereto at a velocity proportional to an assumed velocity of said trainer and directionally controlled by said trainer, a target object simulating a land, air or water borne craft associated with the other of said surfaces and movable relative thereto at a velocity proportional to the supposed velocity of the craft to be repre sented and having a controlled directional head ing, the said surfaces being arranged such that the instant course of said target object relative to the instant course of said course indicator is at all times apparent by visual observation through said transparent surface.

2. The structure as claimed in claim 1, in which each of said surfaces have corresponding positional indicia thereon.

3. In an aviation ground training system, a plurality of aviation ground trainers for simulating the flight of aircraft, a first reference surface, a plurality of transparent reference surfaces superimposed and in parallel spaced relation with respect to each other and with respect to said first reference surface, a plurality of course indi cators, each associated with one of said reference surfaces and adapted to have a motion relative to said one surface with a velocity proportional to museum 11 .anassumed velocity of onefof said trainers :and directionally controlled thereby and rence inclicia -on at least said :filiSiZ lreference' sur lace, whereby the instant course of each of said course indicators relativexto Ia pointon saidfirst reference surface is'cat all times apparent. by'visuai observation throughsa i'ci transparent surfaces;

4. A wind simulating clevice for :use wi-t hxaviati'on ground trainers comprising, .a course indicator movable relative Ito a stationary chart ona supporting table surface at a velocity proportional to "an a'ssumecisvelocity in flight of :an aviation ground trainer and having an instant ihea'ding equivalent to the heading-of said trainelgca mow able surface contacting said chart and having. "its plane of motion at any desirefil angle relative to the a longitudinal .axis of t l-1e table 'surfa'ce,: movable surface having a velocity proportional to the velocity of an assumed wind "amid a dircce tion equivalent thereto, said course indicator being movable on said movable surface anddsplaced therewith in a manner to simulate i6 efiect of an assumed wind :acting on said trainer.

5. in an aviation ground traineraassembly ,for simulating "flight interception problems, an 'avia ti'on flight: trainer ifior simulating: .fiigntxo'f' :an aircraft, a coursefiindiicator :adap'te'd to' hav' translatory motion proportional to'an assumed velocity in flig'ht of said trainer: 21d directionally controlled thereby, a :first. m'ova surfa'ce ha-v mg. a motion equivalent to thexdirect'ionand zproportional to ithe velocity of anassumed W-inciysaici surface supporting saicl course indicator for movement thereon, a target "object havinga controllable. velocity and heading a eprcsentin g. a tare get craft, a second movablesmztaoe tfor supportingwsa'id target object said second movable surface having a velocity "DT'OIJOI'IUlOl'lZlJFfiO"like velocity of an assumed cunvent' ofiche suppm' 11g medium acting on said'ftargetiob' ject mg;

a direction equivalent theretoysaid surfaces eing superimposed and in parallel spaced relation; the

12 upper oneiof' said'sur-faces being composed=of a transparent material whereby the instant positioniofssaid course indicator relative to said target object 3iSi2tt' al 1 "times apparent by "visual observation throughsaid transparent surface.

6. The structure as claimed in claim 4, in whi'chzsaid movable surface is a belt driven at a constant-"speed by an adjustable speed power means.

CARL J. CRANE. GEORGE V. HOLLOM'AN. CARL W; MULLER. RAYMOND K. STOUT.

:REFERENGES CITED.

The following references are of record in the filo of this patent:

STATES PATENTS Number Name Date 830,718 Holt Sept. 11, 1996 1293;74'7 Ford Feb. 11, 1919 1,5'9'6;93'6 lvlengc'len Aug. 24, 192 130E582 Mengden Feb. 12, 1929 L -745,933 Kauch Feb. 4, 1930 1,825,462 Link Sept. 23', 1931' 1,985,265 Smith Dec. 1934 1,985,266 Smith Dec. 1934 2,099,857 Link Nov. 23, 1937 -2,1I9,'083 Link May 31,193 2,131,952. House Oct. l, 1938 2163, 746 Courtois-Sufiit June 27, 1939' 2,164,412 Kos'ter -i July 4, 1939 231711561" Hoov'en Sept. 5, M33 2,1'291663 1 Link c- Nov. 14, 1939 2191-1730 Sjostra nd Feb. 27. 1940- FOREIGN PATENTS Number Country Date 484,243 Great Britain 19233 384,971" Great Britain 19.31

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