US2783955A - Air, land, and water craft - Google Patents

Description

March 5, 1957 J. L. G. FlTz PATRICK 2,783,955

AIR, LAND, AND WATER CRAFT 4 Sheets-Sheet 2 Filed May 2, 1952 IN V EN TOR.

Bbwf? 7516274? 7m March 5, 1957 J. L. G. F`lTZ PATRICK AIR, LAND, AND WATER CRAFT 4 Sheets-Sheet 3 Filed May 2. 1952- March 5, 1957 J L. Q mz ATmCK 2,783,955

AIR, LAND, AND WATER CRAFT Filed May 2, 1 .952 4 Sheets-Sheet 4 2N /50 F0 HL Fig 20 L6 4412-` nl?,

4/ Y 2J /50 '4&0 M l-zg 2l #8 $2@ W L/ United States Patent O AIR, LAND, AND WATER CRAFT James L. G. Fitz Patrick, Staten Island, N. Y.

Application May 2, 1952, Serial No. 285,650

7 Claims. (Cl. 244-22) The present invention relates to a craft which is suitable for travel in the air, on land, and on and under water. The invention also relates to improvements in joints, wing construction, and marine tins and also to improved methods for folding the same.

The present invention constitutes a somewhat revolutionary craft for travel and has manyjadvantages which renders it valuable not only for military use, but also for civilian use. Such advantages would include fuel economy, quiet, versatility, exibility, simplicity, reliability, maneuverability, spin proof, low landing speeds, smaller take oi and landing areas required, and steep climbing ability.

While the wings or ns of the present invention and the joints employed therewith readily lend themselves to any type of marine or aircraft, they are especially valuable to those designed to secure propulsion as well as sustention from the beating or oscillation of such wings or ns.

One of the objects of this invention is to provide a wing or iin which is automatically kept extended by aerodynamic or hydrodynamic loading or resistance and which will have considerable capacity for absorbing shocks and stresses.

Another object is to provide a method for attaching a wing or iin to an aircraft or watercraft so that the hydro or aerodynamic reaction is allowed to position the wing during its beat or oscillation cycle so as to vsecure the maximum efficiency in sustaining and/or propelling the said craft.

A further object is to alter the hydro or aerodynamic qualities of the wing or iin by the manner in which the same is folded or positioned and to secure control of the air or watercrafts stability and manueverability by the wing action alone.

A further object is to vary the stability and control of the air or watercraft either by varying the force of the driving mechanism of the said wing or 1in or by altering the extent and the manner of folding of the wing or tin. L

Another feature of my invention is the provision of a novel type joint which can be advantageously employed in wings, legs, and tins to obtain the type of movement desired when in iiight or in or under the water or when moving along the ground.

A further object is to provide a structure having a system of joints which employ neither pins nor tension members or any other device which is subject to shearing stresses between moving members of the joints and which is adaptable for use in various fields such as air, land, and water craft as well as in artificial limbs.

Another `object is to provide a beating wing which will recover some of the energy it expends on each power stroke.

Another object of this invention is to provide an improved joint for aircraft which will be light in Weight and will have greater durability and ilexibility than a conventional pivot-type universal joint.

2,783,955 Patented Mar. 5, 1957 Other objects and features of the invention will appear as the description of the particular physical embodiment selected to illustrate the invention progresses. In the accompanying drawings, which form a part of this specification, like characters of reference have been applied to corresponding parts throughout the several views which make up the drawings.

Figure l is a perspective view of the entire craft show-y ing the wings extended horizontally in a gli-ding position.

Figure 2 is a perspective view of the entire craft showing the wings folded and the legs extended for movement on land or water.

Figure 3 is a small scale perspective view showing the wings in their uppermost position and the legs in their lowermost position.

Figure 4 is a small scale perspective View showing the wings in their lowest and most forward position.

Figure 5 is a small scale perspective View from the side showing the position of the wings, legs, and tail during a steep landing approach. u

Figure 6 is a small scale perspective view of the vehicle with wings at a position intermediate to Figures 5 and 4.

Figure 7 is a small scale view taken from above showing the wing areas and their centers of pressure thrust forward of the center of gravity to secure a nose up pitching moment.

Figure 8 is a small scale view taken from above showing the wing areas and their centers of pressure held aft of the center of gravity to impart a nose down pitching moment.

Figure 9 is a small scale view taken from above showing the right wing area and center of pressure held aft of the center of gravity while the left wing is held opposite to impart a right hand yawing moment with positive dihedral.

Figure 10 is a cutaway view of the left half of the aircraft and its operating mechanism.

Figure ll is a view of the left wing frame from the front including a part of the fuselage.

Figure l2 is a top view of the left wing taken on the line 12-12 of Figure 11.

Figure 13 is a top view taken on the line 13-13 of Figure 1l of the left wing frame partly folded.

Figure 14 is a top view taken on the line 14-14 of Figure 13 of the left wing frame fully folded.

Figure 15 is a side view of the left wing frame fully folded taken on the line 15--15 of Figure 14.

Figure 16 is an enlarged front View of a portion of the left wing frame showing its operating mechanism and the associated fuselage. y

Figure 17 is an enlarged angular view of the joint uniting the mid-wing frame and the wingtip frame.

Figure 18 is an enlarged angular View showing the means for connecting the individual wing tip frame members to the mid-wing frame.

Figure 19 is an enlarged top view of a portion of the left Wing frame, its operating mechanism and associated fuselage taken on the line 19-19 of Figure 16.

Figure 20 is an exploded view of the left wing frame members with the wing tip member folded.

Figure 2l is an exploded view 0f the left wing frame members seen from the line 21-21 of Figure 20.

Figure 22 is an exploded view of the left wing frame members seen from the line 22-22 of Figure 21.

Figure is an exploded view of a tail frame joint member.

Figure 26 is a side view of two tail frame members showing their controlling cables.

Figure 27 is an angular View taken from below showing the tail section of the aircraft.

For purposes of illustration I have shown how my invention may be employed in a self-propelled amphibious aircraft. It will be realized as the description progresses that my invention is adaptable for use as a surface craft or a sub-surface water craft.

Referring to Figure 1, the craft I have employed to illustrate the invention consists of a fuselage 30 to which is attached a pair of wings 32 and 34. A tail 36 is provided for assisting in the control of the craft. Since the wings 32 and 34 are of substantially identical construction, it will only be necessary to describe the construction of the left wing 34.

Wing 34 has a skeleton framework which is enclosed in a suitable covering 38 as seen in Figure 10. The wing framework shown in Figures 1l to 22 consists of a single inner wing frame member or spar 40 having a ball end 41 which mates with a socket 42 on the fuselage 30. The other end of the single inner wing spar consists of a multi-ball or cylinder 44 which mates with correspond- 1 ing recesses 46 on the mid-wing spar 48. The outer end of this mid-wing spar 48 terminates in multiple cylindrical recesses 52, 54, 56, 58, and (Figure 20). These recesses receive the mating cylindrical ends 62, 64, 66,

68, and (Figures 11, 17, and 18) of the Wing tip spars and ribs 72, 74, 76, 78, and (Figures 12, 17, and 18).

The inner wing spar 40 is held in contact with the recess 42 by means of five cables 82, 84, 86, 88, and 90 (Figures 16 and 19). These cables act together with the shape of the ball 41 and the shape of the socket 42 to limit the angular travel of the member 40 and the rocking of this member about its own longitudinal axis. The degree of freedom of this rock in any given angular position of the member 40 can be controlled by way in which cables 82, 84, 86, 88, and are rigged.

The inner wing spar 40 and the mid-wing spar 48 are held together by the cables 92, 94, and 96 (Figures 16 and 19). Cable 96 also limits the angular opening between the inner wing spar 40 and the mid-wing spar 48.

Each of the wing tip frame members 72, 74, 76, 78, and 80 (Figures 17 and 18) are secured to the mid-wing spar by two pairs of cables 98 only one of which is illustrated in Figure 18. The pair shown are secured on the axis of the cylindrical end and of the corresponding recess and function to hold the parts together. The other pair arranged in a plane at right angles to the first pair of cables function to limit the angular motion of the joint and prevents disjointing at these limits. In addition, the

cables 100, 102, 104, and 106 are provided to fix the relative positions of the wing tip members 72, 74, 76, and 78 when the wing is extended.

The wing tip frame member 80 which carries the leading edge cable is similarly secured to the outer end of the mid-wing spar 48. However, the axis of attachment of the wing tip frame member 80 is at right angles to the other wing tip frame members and it carries at its outer and lower extremity a foot 81 attached by a similar joint. It is constrained to the position shown (in Figure 17) by the springs 82. The foot allows the wing to assist in moving the vehicle when on land.

In all of the preceding and following description, it will be understood that the term cable is used to indicate any elongated flexible member capable of withstanding a simple tension load, e. g. chains, cords, rope, cables, monofilaments, etc. Likewise, where later reference is made to springs, any member having similar elastic properties may be introduced, such as air springs, rubber shock cords, etc.

In order that the wing may fold automatically in the absence of a positive control action and aerodynamic loading, there is provided a plurality of springs which normally pull the wing frame Work into a predetermined folded position as shown in Figures 2, 14, and 15. The inner wing spar 40 is pulled against and parallel to the fuselage axis by the pull of the springs 108 and 110 (Figures 1l, 12, 13, 17, and 19) whose inner ends 111 are attached to the fuselage 30 and whose outer ends 109 are attached to the boss 150 on the wing spar 40. A single spring or a flat elastic rubber member may, if desired, be substituted for springs 108 and 110 as shown in Figures 11, 12, and 13.

ln a similar manner the mid-wing spar 48 is drawn nearly parallel to the fuselage axis by the act-ion of the spring 112 whose inner end 114 is attached to the fuselage and whose outer end 113 is attached to the mid-wing spar 48.

The wing tip members 72, 74, 76, and 78 are similarly pulled into a position roughly parallel to the fuselage by the action of springs 116, 118, 120, and 122 (Figures 11, l2, 13, and 17). Spring 116 is attached to midwing frame spar 48 at the point 117. The wing tip member 80, which is normally held in the position shown in Figure 17 by the springs 82, is forced to fold towards the other wing tip members by the pull of the leading edge cable 85 as the wing tip folds under the action of springs 116, 118, 120, and 122.

In order to impart positive wing opening or unfolding I have provided suitable mechanism such as the conventional fluid actuated piston 124 moving in cylinder 126 (Figures l0, 1l, 12, 13, 16, and 19). The position of the piston 124 in the cylinder is controlled by the introduction of uid under pressure through the tube 128. Cylinder 126 and other cylinders mentioned later are single acting and can only apply tension to the cable attached to their respective piston rods. The pistons may be returned to their position of rest by suitable springs (not shown). Cylinder 126 is secured to the mid-wing spar 48 by the exible attachment or cable 132.

When piston 124 pulls on cable 132, the angular opening between the inner wing spar 40 and the mid-wing spar 48 increases to the limit imposed by the cable 96. Two secondary actions result from the opening just described.

In the first place, tension is placed on the spring 112 which pulls the combined inner and mid-wing sector and the attached wing tip towards a forward position, with the wing section in sliding position. This spring alone cannot, however, hold this position against normal lift and drag forces.

In the second place, the opening of the inner and midwing spars places tension on the cable 134 attached to the mid-wing spar at point 133 and passes through a hole 135 in the front outer end of the mid wing and attaches to the outer wing spar 78 at point 137. The resulting tension unfolds the wing tip to its full extent.

The unique feature of this unfolding arrangement is revealed in the angular changes of the members 40, 48, and 76 as shown in Figures 10 to 22. The inner wing spar moves forward of the fuselage axis and attains a slight upward inclination of its long axis. At the same time the face which was uppermost rocks forward until it faces down. Mid-wing spar 48 turns the face which was facing towards the fuselage downwards and its long axis bends down from spar 40 while opening a large angle as seen from above in Figure 12 between members 40 and 48. Wing tip spar 76 turns that portion of the wing which was its inner face when in the folded condition, downwards. The long axis of the wing tip spar 76 assumes a position nearly at right angles to the fuselage axis and bends slightly down from the axis line of midwing spar 48. In every case, the faces of these members which formerly faced the fuselage when folded, face downwards whenthe wing is extended horizontally.

The position of this entire unfolded wing or partly unfolded wing with reference to the fuselage is determined by many factors such, for example, as the aerodynamic reactions, its inertial and dynamic properties, the ela-Stic structure already described and by the positive forces introduced by the cylinder and piston components 13S-142, 13G- 160, and `140--156.

The piston 138 in the cylinder 142 may be acted upon by fluid pressure conveyed by the tube 144. The piston actuated tension cable 146 which passes through the vertical opening 148 is attached to the inner high point 109 on the boss 150 of the inner wing spar 40. The relative positions of the opening 148 and of the point 109 are such that a full stroke of the piston will raise the extended wing to the position shown in Figure 3.

In this motion of the wing and in the folding motions described the proper shaping of the ball-like surface and its mating recess 42 are important. Likewise, the forming of the inner part of the spar 40 into the overhanging boss 150 and the cam-like projection 157 are necessary. The nature of the wings action is determined in part by the form ofl these members and bythe restraint of the cables 82, 84, 86, 88, and 90, the action of springs 112, 108, and 110, the aeroelastic forces previously mentioned andthe positive action of the cables 146, 154, and by the liat wide tension member 152.

The boss 150 provides points of attachment at -suitable distance from the axis of the spar 40. The boss 150 acts to hold the at tension member 152 at a suitable distance from the axis of spar 40. In each case the purpose is to determine at definite points during the wing stroke the effective moment about the axis of spar 40 which will be produced by the various cables, springs, and actuating tension members thereon attached. To accomplish these purposes, I have formed the inner part of this member with the configuration shown in Figures 20, 21, and 22.

The piston 140 which pulls the wide fiat tension member 152 operates the cylinder 156 and is actuated by fluid under pressure supplied by the tube 158. Assuming that at this instant the wing was in the position shown in Figure 3 and that the pull on cable 146 had been relaxed l then the force on member 152 would cause the wing `to pass successively through the movements shown in Figures 1, 3, 6, and 1l.

During the first part of this stroke the cam 157, by virtue of the construction shown, is active. In the late part of the stroke, the overhang of the boss 150 takes over the moment controlling function. If the piston 140 be'stopped at an intermediate point, a position with -a high dihedral angle ofthe wings as in Figure 5 may be held which is an attitude suited for steep landing glides. Or the position of the wing shown in Figure l may be assumed for normal gliding. Repetitive'action of the piston 124 actuating the folding of the wing, piston 138 actuating the lifting and piston 140 'actuating the downstroke will, if applied in the correct timing sequence, produce beating actions which will provide both sus'- tension and propulsion.

Such cycling of the wings action is attained readily as shown in Figure by a suitable mechanism -such as a cam operated slide valve. In Figure 10 the tubes which carry the lluid under pressure to actuate the pistons-abovementioned are supplied by the multiple slide valve 189. The uid under pressure may be air, supplied to the valve 189 through the tube 254 from the compressor 251 driven by the gasoline engine 250. The fingers controlling the slides are actuated by the cam 188 and the cam followers 190, 192, and 1194, respectively. This cam 188 may be driven at various suitable speeds and throttle valves, not shown, may control the pressure in the respective cylinders.

Without the use of the tail, stability adjustment and control of the aircraftis secured by thev operation of the piston 136 and its corresponding member on the right hand side, of the fuselage. The position of the cable 154 attached to this piston is controlled by the admission of lluid under pressure through the tube 162 into the-cylinder attached to the fuselage by the iiexible attachment 161. I

Cable 154 is attached to the inner wing spar 40 at the point 163. Suitable selection of this point allows a pull on the cable 154 to increase the angle of attack slightly and to hold the wing center of area and pressure to the rear. The combined action then of the piston 136 and its right hand counterpart allow the operator to secure changes of the configuration as seen in the small scale top views, Figures 7, 8, and 9.

In Figure 7 both pistons have been relaxed and the wings sweep forward so that the centers of pressure (x) are forward of the aircrafts center of gravity and a nose up pitching moment results.

In Figure 8 both pistons are pulling on the cables and a sweepback brings the centers of pressure (x) aft of the center of gravity and a divingmoment results.

In Figure 9 the pull on the left hand cable is relaxed causing the left wing to sweep forward while on the right the cable is being pulled and the wing sweeps back. lt is understood that the centers of gravity and pressure are on the same line. If there is a positive dihedral the horizontal components of the centers of pressure (x) will produce a yawing moment and a right hand turn. If a negative dihedral, a left hand turn is produced. If both centers of pressure (x) are carried forward at the same time, a climbing turn will be produced and vice versa.

Side effects such as the production of pitching moments by varying the opposite dihedrals may also be used for control. A configuration such as that shown in Figure 5 may be useful in a steep landing approach at minimum speed, a high dihedral nose up pitching moment from the tail surface and a nose down pitching moment from the wings. This is a combination giving a low lift or drag ratioV suited for this maneuver.

The tail 36 which is thus Aa low speed control adjunct is shown in Figure 27. The type selected for illustration consists of a fabric covering 38 attached by laces 181 to a jointed framework consisting of three members 164, 166, and 168. Between the tail fabric and the wing fabric an elastic fabric 184 is introduced to provide freedom of motion.

The frame members 164, 166, and 168 are shown with three sections united by ball 172 and recess 170 joint, as shownin Figures 24 and 25. These joints are secured together and the angular position of their members is governed by the cables 174, 176, 178, and shown in Figures 26 and 27. By properly pulling on these cables and the cables for the frame members 164 and 166, not shown, the tail surface may be madeto turn down or up or displace its center to the right or the left, or may perform these motions in combination. Such changes in position will produce in a moving aircraft pitching, yawing moments or combined pitching and yawing moments in any desired combination.

For the purpose of illustration I have shown the wing surface made of a strong weather resistant fabric material 36 united by lacing 182 to the wing frame. Also, for purpose of illustration, a single layer of fabric is shown on the after portion of the wing section and a double layer on the leading portion. The leading portion is also shown stiffened by flexible part ribs 186 likewise secured to the fabric by suitable means such as lacing. The porosity of the fabric may be selected to assist in boundary layer manipulation and parts of the surface may be covered by sutiable feather-like surfaces such as shown in U. S. Patent 1,783,029 granted to George R. White on November 25, 1930.

Figure 23 illustrates an alternate method of constructing themid-wingframe. The single spar member 48 is replaced by the two spars 200 and 202. Each has a recessed ending 204 and 206 which rest on the , ballsv 208 and 210 in the modified end of the spar 40 designated as (40M). The remaining cables and those for limiting the angular opening are not shown since they are similar in function to those for the joint between the spar 40 and the spar 48 described heretofore. The outer end of the members 200 and 202 are likewise attached to a block 240 carrying the recesses for the wing tip spars and ribs. The forward rocking action previously described for the spar 48 is provided in this form of construction by the lever extension 212 formed on the member 202. This is secured by cables to the member 200 and as the joint opens it constrains a rocking forward action which is determined by the angular relation of the balls 208 and 210 to the axis of the inner wing spar 40.

In Figure 24 is illustrated a detail of the driving mechanism of the leg shown in Figures 2, 3 and 5. The ball end 220 fits into a recess in the fuselage, not shown and is attached to the leg shaft 222. At the end of shaft 222 is the fin 224 having a stiff leading edge 233 and an elastic and flexible trailing edge 234. The center of area of this fin is to the rear of the center line of the shaft. The cables 230 and 228 pass to controlllable fluid pressure pistons, not shown, and the cables 224 and 232 pass to adjustable tension springs.

The operation of these legs to secure propulsion on land and in water, as well as retractability in the air may be described as follows:

Since the right and left legs are similar in construction, it will be sufficient to describe the operation of only the left leg which has been used to illustrate the invention. For propulsion in the water a stiff tension is imparted to the forward horizontal cable 232 and the position of cable 228 is adjusted by its piston so that the leg shaft stands at approximately right angles to the fuselage or hull. A stiffness suited to the frequency of beat desired is imparted to the vertical cable 224 and the fin is activated by imparting cyclical pulls on the cable 230. This causes the offset lin 224 to act as a propelling hydrofoil during both up and down strokes. The down stroke is caused by the repeated pullings of cable 230 and the up stroke is caused by the tension of the spring on cable 224. There should be little or no motion by the cables 228 and 232.

Steering would be accomplished by either greater force on the right or the left actuating cables or by greater amplitude of their motion or by a combination of both. Automatic mechanism such as previously described for the valves controlling the wing beat cycle may be employed for effecting this motion.

For propulsion on land it is essential that the cable 230 pass through a guiding opening on the fuselage so that the extremity of the leg shaft will have a circular motion about a center line at right angles to the fuselage or hull when the cable is properly fixed. And further, that this circle may be adjusted. by fixing the cable 230 so that the circumferential path of the leg extremity as viewed from the side of the fuselage passes below it.

For normal progression on land, a tension sufficient to lift 'the leg and fin or foot clear of the ground is imparted to cable 224. A tension adapted to the proposed .frequency of leg stroke is imparted to cable 232. A special valve is now used to control the distribution of the fluid under pressure to the cylinder and piston combination which control respectively the pull on the horizontal cable 228 and the vertical cable 230. The fluid on entering this valve is first directed to the cylinder which actuates the vertical cable 230.

Since the action of the spring operated cables 224 and 232 has already drawn the foot forward and up, the pull on the cable 230 brings it in contact with the ground, but in a forward position. The valve continues to feed fluid to the piston actuating cable 230 until a moderate pressure is developed. The development of this pressure in the actuating fluid system now moves a slide in the special valve which locks the fluid in the cylinder actuating tlae vertical cable l23,0 and transfers the incoming uid to the cylinder which carries the piston which pulls cable 228. This pulls the leg to the rear but by virtue of the path previously determined, the foot must move downwards in a circular arc and then upwards as the stroke is completed. This motion of the leg lifts the vehicle and moves it forward.

When the fluid pressure is relaxed, both cylinders discharge freely and the springs restore the leg to its forward position ready for another cycle. Steering is accomplished by a valve which varies the fluid ow to the right and left cylinder combinations. The leg operated for land or in water may be used to assist take-off and to absorb the shock of landing as seen in Figures 3 and 5.

In flight the leg may be retracted by the action of the cable 228 alone. The leg is, of course, booted to the hull for waterproof properties.

The invention hereinbefore described may be varied in construction within the scope of the claims, for the particular device selected to illustrate the invention is but one of many possible embodiments of the same. The invention, therefore, is not to be restricted to the precise details of the structure shown and described.

What is claimed is:

1. A beating wing aircraft comprising, a central body, a beatable wing movable in both horizontal and vertical directions, a drive for beating said wing, a foot extending from said wing to dig in to the ground to propel said aircraft on land.

2. The method of controlling the yaw of a tailless aircraft in flight which comprises, varying the dihedral angle of the wings, and simultaneously and differentially varying the sweep angle of the wings in the same aircraft.

3. An improved aircraft wing drive comprising a fuselage, a female socket formed in said fuselage, an elongated wing frame member having a male end formed to fit the female socket, a protuberance extending beyond and downwardly in front of the leading surface of the wing frame member and adjacent to the male end of said member, another and elongated protuberance extending rearardly from the trailing edge surface of the wing frame member and likewise adjacent to the male end of said member, a cable attached to the first protuberance and passing below the elongated wing frame member and under the second protuberance, a pulling device mounted on the fuselage below and to the rear of the female socket and connected to pull said cable to downwardly beat and simultaneously rotate said wing frame member so that said cable shall always pass below said second protuberance during the beating, said fuselage having also a hole in front of and above the center line of the said female socket, a second pulling device within the fuselage, a second cable for elevating and imparting an opposite rotation to the wing frame member and attached to the first mentioned protuberance and passing thru said hole to the second pulling device, said second cable making an approximate right angle with the first cable when the wing is in gliding position and both are held taut by their respective pulling devices.

4. An aircraft having an elongated fuselage and wings employing a beater motion and comprising three panels joined end to end, a first panel positioned adjacent to the fuselage and being jointed to it by a universal and rotatable joint, a second panel joined to the first panel so that the axis of the joint between the rst and second panel lies parallel to the longitudinal axis of the fuselage when the wing is fully extended in the gliding position, and a third panel joined to the second panel so that the joint axis lies parallel to a line drawn spanwise to the fuselage when the wing is fully folded.

5. An aircraft wing comprising an inner panel, a midwinig panel, a wing tip panel, a joint between the inner panel and mid-wing panel having its axis chordwise so that on folding, their lower surfaces come face to face with the inner and mid-wing panel members substanially parallel to each other, and a joint between the midwing panel and the wing tip panel having its axis normal to these panel surfaces so that when the three Wing panels are folded the lower surface of the wing tip panel will face towards the lower surface of the inner wing panel.

6. An aircraft wing comprising an inner panel, a midwing panel, a wing tip panel, a joint between the inner panel and the mid-wing panel having its axis chordwise, another joint between the mid-wing panel and the Wing tip panel having its axis at right angles to the mid-wing and wing tip plane.

7. A movable fin projecting from a craft, said iin cornprising three parts jointed end to end, a rst part adjacent to the craft being jointed to its by a universal and rota table joint, a second part jointed to the irst so that that axis of the joint between the first and second parts lies parallel to the fore and aft axis of the craft when the n is fully extended at right angles to the craft, and a third part jointed to the second so that the joint axis lies at right angles to the fore and aft axis of the craft when the tin is fully folded.

References Cited in the le of this patent UNITED STATES PATENTS 688,135 Spies Dec. 3, 1901 849,971 Brandl Apr. 9, 1907 886,122 Guthrie Apr. 28, 1908 920,792 Uherkocz May 4, 1909 939,651 Applegate Nov. 9, 1909 10 Rex Jan. 2, Price Ian. 9, Voller Apr. 23, Rawle May 7, Quick Oct. 21, Holle Oct. 27, Thompson Aug. 1, Peterson July 23, Rippenbein July 15, DeCrequy Oct. 5, Woodward Apr. 3, Grunewald Aug. 7, Carey Feb. 19, White Nov. 25, Fehrenbach May 24, Melville Feb. 14, Jelalian Feb. 5, Gray Oct. 15, Shanley July 13, Gluharel Aug. 18, Nagle Oct. 9, Johnson Oct. 27,

FOREIGN PATENTS Great Britain V Great Britain France Apr. 9, France Apr. 26,

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