US2588941A - Model glider - Google Patents

Description

E. A. STARK MODEL GLIDER- March 11, 1952 4 Sheets-$heet 1 Filed Sept. 15, 1947 INVENTOR. fowl/20 ,4. STF/EK HTTOENEXS March 11, 1952 E. A. STARK 2,588,941

MODEL GLIDER Filed se 15, 1947 4 Sheets-Sheet 2 I INVENTOR. V EDWH/QD 7. 57, 595

March 11, 1952 E. A. STARK 2,588,941

MODEL GLIDER Filed Sept. 15, 1947 4 Sheets-Sheet a INVENTOR. EDWHED 6 .5mm

E. A. STARK MODEL GLIDER March 11, 1952 -4 Sheets-Sheet 4 Filed Sept. 15, 1947 INYVENTOR. [an 420 fl.ST/i2/ KTTOENEYJ Patented Mar. 11, 1952 UNITED STATES PATENT OFFICE' MODEL GLIDER Edward Adolph Stark, San Francisco, Calif.

Application September 15, 1947, Serial No. 774,165

2 Claims.

This invention relates to model airplanes and it has reference more particularly to model airplanes of the glider types, that are designed to be manually launched into the air by towing lines or catapult types of devices, and which embody therein the fundamental principles of controlled flight.

It is the principal object of my invention to provide a model airplane of the above stated character that will afford amusement both to persons flying it and those watching it while flown, and which also is of educational value in that a knowledge of the fundamental principles of the flight of such aircraft and the manner of trimming an airplane to produce definite and controlled flight maneuvers may be gained from the model.

It is also an object of my invention to provide novel features in'the design and construction of glider model airplanes, particularly in the details of a stabilizer unit or tail assembly, and parts associated therewith, whereby the direction of gliding and the various flight maneuvers provided for in the conventional airplane may be determined and controlled.

Another object of my invention is to provide novel means, in a catapult launched model plane of this type, that will prevent premature looping under the initial launching force and make it possible for the plane to reach maximum elevation.

Still further objects of my invention reside in the details of construction of the stabilizer unit and its manner of mounting; in the details and assembly of its controlling parts and in their mode of adjustment as a means of determining and controlling the flight maneuvers, as will hereinafter be fully described.

. In accomplishing the above mentioned and other objects of my invention, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein- Fig. 1 is a side view of a model airplane, in which the novel features of the present invention are embodied; certain portions of the fuselage, and the near wing, being broken away for better understanding of details of construction and assembly of parts.

Fig. 2 is a front end view of the present model airplane.

Fig. 3 is a side view of the tail assembly, or stabilizer unit, of the present airplane, showing an alternative form of stabilizer positioning and control means.

Fig. 4 is a top, or plan view of the present model airplane as seen in Fig. 1, parts of its wings being broken out to reduce the size of the View;

Fig. 5 is a cross section, taken on the line 5-5 in Fig. l, particularly illustrating the pivotal mounting of the tail assembly or stabilizer unit in the tail section slot of the fuselage.

Fig. 6 is a top view of the tail portion of the fuselage, showing the stabilizer unit as trimmed for a left rudder turn.

Fig. 7 is a similar view showing the stabilizer unit as trimmed for a right rudder 'turn. I

Fig. 8 is a view illustrating a suitable form of catapult device for launching the model plane of Fig. 1 in flight, and illustrating the mode of its attachment to the plane for a launching operation.

Fig. 9 is a side view of a model airplane of a modified design, together with a type of launching device that is suitable therefor.

Fig. 10 is a view illustrating the use of a parachute drag in connection with the plane of Fig. 9.

Fig. 11 is a view illustrating the release of the towing harness from the plane by means of the parachute.

Fig. 12 is a side view of a plane designed to resemble a fish.

Fig. 13 is a view illustrating another design for the nose end of the plane.

Fig. 14 is a front end view of the same.

Fig. 15 is the underside view of the attaching spoon as used with the catapult device for launching the plane.

One of the principal features of thepresent invention resides in the provision, in a model plane of glider type, of a stabilizer unit or tail assembly that may be manually adjusted for various flight maneuvers and which will automatically adjust itself during the initial interval of high catapulting or launching speed to prevent any premature looping, and will thus permit the plane to attain maximum altitude under its launching force; also, which stabilizer unit will, near the end of the climb of the plane under the launching or catapulting force, and as the initial speed diminishes, automatically adjust itself to cause the plane to make one or more short loops or turns, and finally cause it to glide normally to rest in a straight line or in spirals, in accordance with the adjustments that have previously been made.

Referring more in detail to the drawings- In its present preferred form of construction, as shown best in Figs. 1 and 4, the model airplane comprises a fuselage of rigid, and preferwood, such as pine or spruce, also it might be Fixed to the opposite sides of the fuselage,

are the wings, designated by reference numerals l3 l 3, and these are symmetrically formed and located,.and are so secured to the fuselage, as observed in Fig. 2, that they extend upwardly and. outwardly at a proper dihedral to give a desired stability or balance to the plane in flight. The nose portion Illa of the fuselage is forwardly and upwardly rounded along its bottom edge and is somewhat increased in thickness, as will be understood by reference to Fig. 4, to give the desired longitudinal balance to the structure; the center of gravity of the plane being located in the fuselage, a distance back of the line of the forward edge of the wings approximately equal to one-third the distance between the for-. ward and rearward edges of the wings.

A downwardly bowed runner or skid I5 is attached to the lower edge of the nose portion of the plane as an aid to and protection in landing.

To impart a resemblance to certain types of airplanes, the fuselage is formed with a cockpit l6 anda windshield l1. At the nose of the fuselage, a launching hook I8 .is attached. This has its shank fixed between opposite side portions of the nose section, to extend forwardly and downwardly, as will be understood by reference to Fig. 1. At its lower end the shank is formed with adownwardly and rearwardly turned hook portion for engagin the launching means. as will presently be explained.

. The tail structure or stabilizer unit, which is designated in its entirety by reference character l2, comprises a rigid, one-piece, vertical stabilizer fin- 20, formed along its bottom edge between forward and rearward ends with a downwardly extending tab 20:23. This portion 200: is contained in a vertical and longitudinally extending slot 22 formed through a somewhat widened tailportion lb of the fuselage, as will best be understood byreference toFigs. 1 and 5; the, tail portion being somewhat widened to V receive the slot. Formed on the top edge of the tail portion Hlb, at opposite sides of the slot 22 therein, are upwardly projecting flanges 23-23, and a pivot pin 25 is extended directly through these flanges and freely through the bottom edge portion ofthe stabilizer fin 263, to pivotally attach the stabilizer unit to the fuselage for limited pivotal movement about the axis of the pin, as presently explained.

The clearance between the sides of the slot 22 and the side surfaces of the depending tab portion 201x 01 the stabilizer fin 20 is such as to permit desired lateral, angular adjustment of the stabilizer fin in opposite directions, or to opp0- site sides of the longitudinal line of the fuselage,

as has been indicated by the oppositely inclined position of the fin as seen in Figs. 6 and 7,.

for right or left rudder turning.

To keep the stabilizer unit properly centered in the slot, in order that the desired angular adjustments may be made, spacer blocks, as at 2B, are fixed to its opposite sides at points immediately above and below the point of passage of the pivot pin therethrough. These blocks engage with the opposite sides. of the slot, to retain the stabilizer substantially centered'at its place of mounting on the pin, but do not interfere with the making of angular adjustments.

As a detail of construction, a metal washer 21, shown in Fig- 1, is set in the stabilizer fin 20 to receive the pivot pin 25 therethrough and to prevent wear on the stabilizer. The hole in the washer has a diameter slightly greater than that of the pin, to allow for the lateral adjustments'of the stabilizer. 7 a

It is also shown in Fig. 1 that the mounting tab 29a: of the stabilizer 29 extends downwardly through the slot 22 and somewhat below the lower edge of the tail section of the fuselage in order that it may act as a runner or skid for landing purposes. The extreme end of the tail is fiared, as at 29, to provide a good finger hold for launching purposes.

Fixed to the opposite sides of'the, vertical fin 20, rearwardly of the pivot pin and somewhat above it, are the horizontal stabilizers 3ll30,

located slightly above the level of the tail portion of the fuselage. An important feature of the assembly of parts embodied in the stabilizer unit resides in the fact that the pivot pin 25, about which the unit is adjustable, is located below the centers of projected frontal. area of the stabilizer unit and of gravity. Thus pressure of the slip stream against the leading edges of the fins will normally operate to exert a backward tilting force against the unit'which would move it from the full line position shown in Fig. 1 toward the dotted line position, thus to change the angle of the horizontal stabilizers from that substantially at the horizontal level of the pivot pin 25, and at its end is fixed to a hook 31 that is mounted in the top edge of the fuselage at a point forward of the tail section. The direction and pull of the rubber band is such as to normally hold the stabilizer unit in position for hands off flight. V f

The hooks 36 and 3-1 are formed of soft wire of small gauge and they extend substantially from their mounting members and may be bent to extend in various directions. By properly bending the shank of one or of both of these hook-like members 36 and 31, the tension of the band may be increased or-decreased, and the position of the unit adjusted and the horizontal fins tilted upwardly to more or less degree. .Also, by bending them to one side. or the othenlthe stabilizer unit may be adjusted to variousQpositions, for example, from a position for straightaway fiight, as in Fig. 4, to that for making right rudder or left rudder turns, as has been illustrated in Figs. 6 and '7.

By a proper bending of the wire hook 31 the stabilizer unit can be held at a position to cause high zooming loops to be performed.

In this connection also, it is observed that I have provided ailerons 38 set within the rear edges of the wings l3, as shown in Fig. 4, and these are secured at the hinge line by means of short inset pieces of wire, as at 39, that may be bent to retain the ailerons yieldingly at set positions to coact with the rudder fin for right or left spirals. For normal flight or gliding, the ailerons should both be set in the same relationship, and they may be adjusted as required to give the proper lift to the front end of the plane.

In Fig. 3, I have shown an alternative method of adjusting and holding the tail assembly in position. In this arrangement, a length of spring wire 40 is secured at one end in the top edge of the fuselage, forwardly of, the tail assembly, and the wire is bent back to extend along the top edge of the fuselage. At its end it is formed with a downwardly opening hook 4|. The wire is under spring tension and its normal tendency is to spring upwardly at its hook end. However, the extent to which this upward springing is possible is limited by means of a rubber band 43 that encircles the fuselage and extends over the wire in a manner to, pull it downwardly. By slipping the rubber band toward or from the free or hook end of the wire, it may be drawn down or allowed to spring up to more or less extent.

Fixed in the forward edge of the stabilizer fin is a hook or loop 48 in which the downwardly turned end of the hook 4| is engaged for the purpose of holding the stabilizer unit yieldingly in a set position of adjustment. Lateral or angular adjustment of the stabilizer in this combination is made possible by bending the wire 40 toward one side or the other of the fuselage. The up and down tilting of the stabilizer unit is adjusted by the adjustment of the rubber band 43 that controls the extent of the up and down position of the hook 4|.

Associated with this means of adjustment shown in Fig. 3, is a rubber band 50, that is applied about the tail end portion of the fuselage rearwardly of the stabilizer assembly, and against which band the lower edge of the fin rearward of the pivotal connection, may engage. By shifting this band 50 forwardly or rearwardly, the extent of the upward tilt of the horizontal fins may be limited to more or less degree, by reason of the lower edge of the fin, rearwardly of the pivot, engaging with this band. Thus, through the adjustment of the rubber bands 43 and 50 and the bending of the wire 40 toward one side or the other, the stabilizer unit may be yieldingly held at any set position within its limits of adjustment.

As a novelty feature, I have provided for, and in Figs. 2 and 4 have illustrated, the attachment of whistles 52 to the opposite sides of the fuselage directly below the wings. These whistles are of a type adapted to produce a shrill whistling sound when the plane performs its diving maneuvers. As an alternative arrangement, I may use one whistle and mount it in the nose of the fuselage, as indicated at 53 in Fig. 1.

In Fig. 8 I have illustrated a type of launching catapult suitable for the airplane of Fig. 1. This comprises a handle lever 80 provided at its upper end with a hinged tip 6| which may swing forwardly and downwardly and to which one end of a strip 62 of strong slingshot rubber is attached. To the free end of this rubber strip there is fastened a swiveling, spoon-shaped disk 55, as shown in Fig. 15, provided with a hole 66 through the center portion for receiving the launching hook I8, as in Fig. 1. This type of slingshot catapult is suitable for launching the light type of airplane shown in Fig. l, and the method of attaching is as shown, and the launching is after the fashion of casting a stone from a slingshot.

In Fig. 9 I have illustrated a modified or bomber type of model airplane with a launching means of reel type. In principle, the design of the plane is like that already described, and the operations of its parts are also as previously described. However, because of its greater wing span and type, a different type of launching means is desirable. The launching means shown comprises a light-weight housing H! with hand grip portion fixed thereto at one side. Contained in the housing is a gear driven reel 12 on which a tow line 13 is adapted to be wound at high speed. The gearing may be turned by a hand crank 75 and the towing speed is governed by the gear ratio and rate of turning of the crank. This speed may be sufiiciently greater than the normal gliding speed to cause high and rapid lift by the wings and extra pressure of slip stream to tilt the horizontal stabilizer back slightly, giving it enough lift to hold the tail up and damp out any tendency to yaw excessively.

At the top of the climb, the reeling is. stopped and momentum of the plane will carry it free of its towing harness.

This release of the towing harness can be most effectively insured by use in connection therewith of a parachute drag as shown in Fig. 10, wherein it is noted that a parachute is connected by means of a line 8| to the tow line 13. As soon as pull on the towing line, effected by the winding gear shown in Fig. 9, is stopped, then the parachute drag through its connecting line 8|, pulls the spoon 65 from the hook and the plane is freed.

In Fig. 12 I have illustrated the designing of the fuselage to resemble a fish and to add interest to the design I have also mounted a small figure representing a gremlin on the fuselage forward of the cockpit.

In Fig. 13 I have illustrated the fuselage as designed with a gargoyle nose 86 and in Fig. 14 I have shown that the whistles 52, as used in the plane of Fig. 2 may be enclosed in the mouth of the gargoyle. This design also can be made more attractive and interesting by the addition of a gremlin as shown or in other positions.

Referring now more particularly to the airplane of Fig. 1, and the catapult launching means, it will be understood that with the initial catapulting speed, the pressure of the slip stream against the leading edges of the stabilizer fins will cause the unit to tilt backwardly, from a normal gliding position, against the tension of the rubber band 35. This backward tilting automatically gives the horizontal stabilizers 30 a positive lift angle, acting to guide the model in a more or less straight line of travel during the interval of high speed climb. During this interval of high speed, the model will attain considerable altitude, but at or near the end of its climb, speed diminishes and the tension means 35 overcomes the pressure of the slip stream and pulls the stabilizers :back to normal gliding adjustment. However, the plane will still have considerably more than gliding speed and will then make a short loop or Immelman, and then settle into a long glide back to the ground. The glide may be in spirals and in a direction as determined by the adjustment of the ailerons and/or stabilizer unit by the bending of wires 36 and 31 as previously explained.

In the model plane shown, in relation to the horizontal attitude of the tail stabilizer, the wings have an'inclination of about 2 /2 or 3 degrees. Dihedral of wings and slightly low center of gravity takes care of lateral stability. In calm air, at constant speed, with the load properly distributed and controls correctly set, the model will have a tendency to fly hands off. However, should the speed be suddenly and considerably increased, the plane will stall or loop over without the present provision of automatic adjustment.

It is only a matter of trial and observation to become expert in setting the various controls to obtain the results or flight characteristics that are desired.

Having thus described my invention, what I claim as new therein, and desire to secure by Letters Patent, is:

1. A model airplane of glider type designed for catapult or tow launching, comprising a fuselage having a vertical slot through its tail portion and equipped with wings set for normal gliding flight, a rudder fin set vertically in the said tail slot of the fuselage, a pivot shaft extended transversely through the fuselage and rudder fin and mounting th latter for pivotal action on the fuselage, elevator fins fixed rigidly to the'rudder fin above the pivot shaft and extended to opposite sides thereof, said rudder fin having limited angular adjustment in said slot for turning the plane in opposite directions, and a rubber band, means connecting the band under tension to the forward edge of the rudder and to the fuselage to yieldingly maintain the elevators at a set posi tion for normal gliding action, said means being adjustable laterally of the longitudinal line of the fuselage to provide for changing the angular setting of the rudder relative to the fuselage.

2. A model airplane as in claim 1 wherein the means which attaches theends of the rubber band to the fuselage and rudder also are adjustable relative to each other to increase or de crease the tension of the band and "to effect change in normal gliding angle of the elevators.

EDWARD ADOLPH STARK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,300,564 Bliesath Apr. 15, 1919 1,723,618 Hodgson Aug. 6, 1929 2,034,143 Jacobs Mar. 17, 1936 2,323,506 Willard July 6, 1943 2,404,922 Padgett July 30, 1946

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