US3104642A

US3104642A - Carrier wing unit for a craft with a constant predetermined lift, and selfvariable incidence

Info

Publication number: US3104642A
Application number: US61531A
Authority: US
Inventors: Piazza Giuseppe
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-11-16
Filing date: 1960-10-10
Publication date: 1963-09-24
Anticipated expiration: 1980-09-24

Description

Sept. 24, 1963 IAZZA CARRIER WING UNIT FOR A CRAFT WITH A CONSTANT PREDETERMINED LIFT, AND SELF-VARIABLE INCIDENCE Filed Oct. 10, 1960 2 Sheets-Sheet l GIUSEPPE PIA A INVENTOR BYM/M,w u pun/=15 ATTORNEYS Sept. 24, 1963 PIAZZA 3,104,642

G. CARRIER WING UNIT FOR A CRAFT WITH A CONSTANT PREDETERMINED LIFT, AND SELF-VARIABLE INCIDENCE Filed 001;. 1.0, 1960 2 Sheets-Sheet 2 INVENTOR GZU5EPPE PIAZ 2A BY MAM, M WW4 ATTORNEYS United States Patent 3,104,642 CARRIER WING UNIT FOR A CRAFT WITH A CONSTANT PREDETERMHNED LIFT, AND SELF- VARIABLE INCIDENCE Giuseppe Piazza, 3 Via Munizioni, Messina, Italy Filed Oct. 10, 1960, Ser. No. 61,531 Claims priority, application Itaiy Nov. 16, 1959 6 Claims. (Cl. 11.4-66.5)

It is known that the carrier Wings applied to a hydrofoil craft are for the purpose of lifting during the motion the hull out of the water to minimize the resistance to motion and to obtain greater speeds for a given power.

The lift of the wing system is mainly a function of the speed of the immersed wing surface and of the incidence angle of the wings.

The lifting wing systems applied to the crafts must mainly ensure:

The take off or raising of the hull from the Water;

The level or height of navigation on the water level;

The trim and the longitudinal stability;

The transverse stability.

The lifting wing systems known up to now suffer certain disadvantages which are common to almost all of said systems, and said defects may be summarized as follows:

A change of the longitudinal trim causes a change of the wing incidence and therefore a variation of the lift;

The navigation in direction at right angles to the wave direction (head or following waves), due to the variation of level of the water and the orbital motion of the waves causes a variation of the lift, which increases or decreases due to both the variation of immersion of the lifting wing surface and to the specific unitary thrusts which are variable in relation to the aforesaid orbital movements.

The variation of lift of the fore wing unit of. the craft is normally out of phase with respect to that of the stern wing unit.

The navigation in a direction parallel to the wave direction, in addition to the effect described above causes an oscillating variation of lift (increasing or decreasing it) putting out of phase the lift of the starboard wing unit with respect to that of the port wing unit.

The above discussed disadvantages in the practical application of such hydrofoil wings cause variations of height from the water level and pitching and rolling movements which are prejudicial to the safety of the navigation. In fact:

(a) Assuming that the fore wing is in a wave trough and the aft wing in a wave crest, the boat bow will go down and the boat stern will go up, the boat gets a bow heavy trim and therefore the incidence of the wings on the horizontal plane diminishes, and can also in certain cases reach a zero valuethe lift of the wing system is thereby reduced or annulledthe boat will be lowered and the bow will strike against the crest of the subsequent wave tending to dive into it;

(b) Assuming that the fore wing is in a wave crest and the stern wing in a trough, the bow goes up and the stern is lowered; the boat assumes a stern heavy trim and therefore the incidence of the wings to the horizontal plane increases so that the total lift of the foil system goes up to almost double, the boat is raised and tends at the limit to porpoise out of the water with the conseice 2 quent progressive reduction of the transverse stability and the consequent danger of heeling over:

(0) Assuming the boat to be running parallel to the wave formation (i.e. with the waves coming athwarthship), at one side the wings will be more immersed than at the other side, and at this side the boat tendsto raise, rotating about a longitudinal axis. The rolling oscillation thereby obtained is remarkably uncomfortable for the passengers of the boat and under particular synchronism of conditions between the natural oscillating period and the speed of the waves, the heeling angle tends to increase and sudden capsiz'ing of the boat on the Water can occur.

The present invention-removes the above mentioned defects ensuring a safe movement over the water an the maximum comfort for the passengers.

The invention will now be described more-particularly with reference to the accompanyingdrawings, in which: FIG. 1 is a schematic sideelevation view of a ship with Wing units mounted on the bow and the stern of theship;

FIG. 2 is a partial top plan view of the construction of FIG. 1; L

FIG. 3 is a front elevation view of the construction of FIG. 1; i

FIG. 4 is a schematic side elevation view of a ship with a single wing unit thereon;

FIG. 5 is a side elevation view, on an enlarged scale;

and partly in section of the spring tensioning means for theembodiments .of FIGS. 1 and 4; and.

FIG. 6 isa diagrammatic view of a wing unit with the forces and moment'arms shown thereon.

"The present invention comprises arranging thelwing units as hereinbelow described- -In FIGS. 1, 2 and '3 the' wing 1. is secured to a first arm 2 near the, middle of its length and to a transverse. fin'3, at one end thereof. The arm 2 and tin 3 have the other endsv thereof securedto an axle 4, ,On the axle 4., is secured a second arm 5. The axle '4 is" supported in conventionaljournal bearings 6 secured to the hull. On the bottom of 'the armZ is a second wingalowhich extends horizontally. The as-. sembly of the

parts

1, ,2, 3, 4,5 and 1h can thus effect rotational oscillations in the bearing 6. In the FIGS. 1 and 3 the bow of the ship, is on the right hand end of the figure and the craft moves from theleftto the right. With reference tothe ship, the wing 1 extends outwardly,

upwardly and forwardly, with the end connected to fin 3 the foremost end, so that theline of application of the" total thrust lies abaft the axis'of rotation through axle 4. Thetorque produced by the thrust is balanced by the torque produced by a spring 7 which acts on the end of the arm 5. I r

The adjustment of the compression of the spring =7 can be produced by means of a load adjusting'system comprising screw 8, the detail of which is shown, on a:

larger scale in FIG. 5. The'spring 7 and the load adjusting means can be employed, such as a mechanical hydraulic system, mechanical-pneumatic system, a hydro-pneumatic system or othersuitable system. movement of arm 5 when the hull is in a stationary condition and when the ship is just starting, a stop 9 can be screw 8 have been" mentioned by way of example, and other'conventional In order to limit the Q the application arm of the lift from x to 2.

3 positioned in a suitable position. Said stop thus limits the maximum incidence angle of the wing.

'In the above described wing unit there are combined in a single complex concept three elementary features: first the possibility of wing rotation so as to obtain a change of the incidence angle automatically; secondly,-

the arrangement of the wing which extends outwardly, upwardly, and forwardly relative to the hull so that the thrust center or, more exactly, the evolute of the thrust centers moves away from and abaft as the hull rises and the draft of the Wings decreases; and thirdly that the spring, or other suitable system causes, for any rotational displacement of the wing, a change of the reactive moment higher than the variation of the active moment produced by the action of lift on the wing 1.

For efiicient operation of the Wing unit, the three above described features are absolutely inseparable and" they must be concurrently used. The wing unit thus provided virtually always gives the same thrust and ensures the same draft height even when one changes the speed, navigates in a rough sea and when, due to the rough sea, the water is subjected to orbital motions which influence the specific thrust with wings having a fixed incidence.

The embodiment of FIG. 4 differs from the II1bOdlment of FIGS. 1-3, in that there is only a single wing unit provided, the wing unit being identical in every respect with the wingunits of the embodiment of FIGS. 1-3. The single wing unit of FIG. 4 is positioned substantially amidships of the ship.

, In FIG. 6 there is shown an example of the operation of the wing unit in which, for the present, the effect of the horizontal wing 10 has been omitted.

The total lift produced by the wing at a normal draft NN is denoted by S. Such'lift is applied at the thrust center 11 at a distance x from the vertical plane passing through the axis of rotation. The active lift moment is given by the product S-x. force produced by the compression of the spring with y denoting the application arm thereof. The reactive moment is given by the product C -y. The Wing unit is in equilibrium if S-x=C-y. For sake of clarity, the drag of the wing in the water. has been purposely neglected, since the moment thereof is of the same sign of that of the lift, has a noticeably lower value and, anyway, it may be assimilated to the lift moment.

Let it be assumed that in the crossing of a Wave crest the draft of the wing, FIG. 6,'moves from NN to AA and the lift center, due to the shape of the wing which extends forwardly, moves from n to a thereby reducing the application arm of the lift from x to z. By virtue of the additional lift produced by the wing surface submerged by the wave crest NNAA, the wing will rotate slightly abaft, that is toward the left side of the figure, and at the same time the spring will undergo a. further compression thereby increasing the force from C to C and therefore the reactive moment from C-y to C-y. The lift center a by virtue of the wing rotation will be moved backwardly and the initial distance 2 will increase, let

it be assumed for sake of clearity, until it again becomes x, by virtue of the backward rotation, the incidence angle of the wing decreases and consequently the specific lift produced by the submerged wing surface also decreases. Denoting by S' the total lift produced by the draft-AA, the new equilibrium position-will be obtained when S'-x=C-y. But, C by virtue of the greater compression of the wing, being greater than C, S should also be, higher than S. In consequence, there being available a greater lift, the wing will tend to lift out of the Water,

returning from the draft AA to the normal draft NN.

Similarly, let it be supposed that in the crossing of a wave trough the wing draft, FIG. 6, will move from NN to RR and the lift center from nto r thereby increasing In consequence of deficiency of lift of the wing surface NNRR,

In addition, C denotes the.

be assumed for sake of clarity, until it again becomes x;

4 exposed by the trough, the wing will that is to say toward the right hand end of the figure, and

reactive moment will decrease from C-y to C"-y. The

lift center r, due to the Wing rotation, will have moved forwardly and the initial distance I will be reduced, let it again due to the forward rotation of the wing, the incidence angle of the latter increases and so'also is the The evolute of the thrust centers is the line e, FIG. 6,

which joins the points 1', n, a, that is the line along which the thrust center moves upon the change of the submergance of the wing surface.

Other modifications of the wing unit structure are possible, for instance the coupling of the axles 4 to each other, or the axles 2 are joined to each other forming a single axle and the ends of the wings are also joined to each other. The unit will still act as described above.

Again, by Way of example, be it'assumed of embodying a wing unit as shown in FIG; 3, where/the reactive moment is obtained by a compression spring whichwill be suitably loaded to createthe reactive moment balancing the'active momentdue to the l-iftpnoducedby the wing at the desired depth. 7

By way of numerical example let us assume that the portion of the weight to be supported by the wing unit will be 1000kg., the lift produced by the wing when at the desired depth, with a given immersed surfacev and with a given incidence angle will be 1,000 kg., the arm of lever of the total lift 0.50 m.; the spring compressed at 500 kg, the arm of lever of application of the spring 1.00 m.

The active moment will be 1.000 kg. 0.50 m.=50 kgms.

the reactive moment will be I 500 kg. 1.00 m.=500 kgms.

and therefore the moments are balanced and the system is in equilibrium.

Assume that the wing surface will entera wave crest, increasing the immersed surface by 20%. were of the fixed incidence type, the lift would beincrease by 20% reaching thus a value of 1,200 kg. against the 1,000 kg. forming the weight to be supported, impart ing thus a sudden movement to the boat. By the wing unit considered in this invention, the operation is as follows: due to the greater immersion of the wing, and-to, the location of the wing surface, the center of thetotal lift moves forward reducing the arm of lever of application of the lift, say of 2% (factor 0.98) but since. due

to the greater instantaneous lift the wing unit will rear- Wards rotateupto the novel equilibrium position, also the center of lift will rearwa-rds move together with the wing, increasing the arm of lever of application of the lift, say of 3% (factor 1.03); by the rotation of the unit,

the spring will be further compressed, and due to its characteristics, say of 5% (factor 1.05); the arm of lever of application of the spring can be considered unchanged.

If Sis the lift at the novel location of equilibrium of the wing unit, the active moment will be: I

s- 0.50 m. 0. 98 1.03 the reactive moment will be I kg. 5 0 1.-05 f 1.00 m.=525 kgms,

rotate ahead slightly, I

If the wing Since the two moments, for the equilibrium, must be equal we will have:

S 525 kgms.

Also in this case the loss of lift With respect to the weight to be supported is minimum and practically the lift may be considered constant.

Also, it is to be considered that the lift increase or decrease, when passing the crests or troughs of the Waves, being minimized by the quick elastic action of the Wing unit according to the present invention, impart no movement to the boat or craft due both to the short duration of the greater or minor lift and to the inertia of the craftmass. I

The weight of a craft may change in function of the passengers load, the fuel load and so on. Considering again the preceding numerical example be it assumed that the weight at minimum load of the craft will be 4000 kg. to be subdivided into 1000 kg. unit, while the full load weight Will be 4600 kg. to be subdivided into 1150 kg. for each of the four wing units. Be it assumed, also that the same immersion depth will be desired in any case for the Wings; therefore to have a thrust of 1150 kg. instead of 1000 kg. at the same speed and for the same immersed wing surface, a greater incidence angle will be necessary, and this will be obtained by imparting a greater compression load to the spring determining thus a forewards rotation of the wing unit up to the new equilibrium position. Due to the rotation of the wing unit the center of lift, however reduces its application arm of lever, say, of 4% being reduced thus from 0.50 m. to 0.48 m.; the active moment to be balanced will be 1150 kgs. 0.48 m.=552 kgms.

I If C is the compression fonce of the spring and com sider ing unchanged the application arm of lever of the spring at 1.00 m. we will have C l.00 m.=552 kgms. wherefrom it may be assumed that the spring in its novel equilibrium condition must have a load C=552 kg. But,

=kgms.

since in the rotation 'of the wing unit the spring has expanded reducing its load, say by 7% with respect to the original load, the difference of the compressive load to 'be previously applied will be:

552 1.07=500=about 90 kgs.

In the practical embodiment the change of the com pressive load to be imparted to the spring may be obtained, for instance, by moving the rest for the spring by a set screw, or by connecting the spring to the piston of a. hydraulic cylinder and the latter to a hull structure or by any other known suitable system.

The data shown in the above specification of the operation of the unit have only exemplary and indicative nature, and changes could be entered without departing from the scope of the claims.

The lift of the Wing system, as aforesaid, is basically depending upon the speed, the immersed wing surface and the incidence angle, but also other factors affect the lift: the streams generally and the general state of for each wing smoothness and cleanness of the wing surfaces. Also invention since the wing will change automatically its incidence until reaching the desired lift.

' At the start, being the specific pressure on thewings nul or minimum, the wing units will have a greater incidence angle, which may anyhow be limited, rendering easier the takeoff.

I claim:

1. In a ship having a hull, a self-adjustable hydrofoil wing unit comprising, anaxle adapted to be rotatably mounted in said hull for rotation about a horizontal axis, an arm mounted on said axle and depending downwardly and rearwardly of said hull, a first wing mounted on the arm at the middle portion of said wing, said first wing extending outwardly and upwardly of said arm and forwardly relative to said hull 'and inwardly and down- Wardly of said arm and rearwardly relative to said hull, a fin connected between the upper forward end of said first wing and said arm where it is mounted on said axle, said arm extending below said first wing, a second wing mounted on the end of said arm and extending horizontally, a further arm mounted on said axle, and reaction means connected to said further arm for exerting a reaction force thereon to rotate said funthcr arm around the axle in a direction opposed to the direction said arm will be rotated by the lift forces exerted on said wings. l

2. A wing unit as claimed in claim 1 further comprising a stop positioned adjacent said further arm on the side thereof opposite said reaction means for limiting the movement of said 'arms when the hull is stationary or is accelerating to the planing condition.

3. A ship having a hull, "a pair of self-adjustable hydrofoil wing units, one on each side of the hull and lying in a plane transverse to the centerline of the hull and adjacent the middle of the hull, each wing unit comprising an axle rotatably mounted in said hull for rotation about a horizontal axis, an arm mounted on said axle and depending downwardly and rearwardly of said hull,

a first wing mounted on the arm at the middle portion of said wing, said first Wing extending outwardly and up- Wardly of said arm and forwardly relative to said hull and'inwardly and downwardly of said arm and rearwardly relative to said hull, a fin connected between the upper forward end of said first wing and said arm where it is mounted on said axle, said arm extending below said first wing, a second wing mounted on the end of said arm and extending horizontally, a further arm mounted on said axle, and reaction means connected to said further arm for exerting a reaction force thereon to rotate said further arm around the axle in a direction opposed to the direction said arm will be rotated by the lift forces exerted on said Wings.

4. A ship as claimed in claim 3 in which the axles of said pair' of wing units are connected to each other to form a single axle extending completely across the hull.

5. A ship having a hall, a first pair of self adjustable Wing units one on each side of the hull and lying in a plane transverse to the centerline of the hull and passing through the how portion of said hull, and a second pair of self adjustable wing units one on each side of the hull and lying in la plane transverse to the centerline of the hull and passing through the stern portion of said hull, each wing comprising an axle rotatably mounted in said a hull for rotation about a horizontal axis, an arm mounted on said axle and depending downwardly and r earwardly of said hull, a first wing mounted on the arm at the 7 8, ineans connected to said further arm for exerting a ream FOREIGN PATENTS tion force thereon to rotate said further armaround the axle'in a direction opposed to the direction said arm will 453,111 Britain 3 be rotated by the lift forces exerted on said wings. 493,176 Gmat Britain 1938 6. A ship as claimed in claim 5 in which the axles 0f 5 582,985 Great Britain Dec. 4, 1946 said pairs of wing units are connected to each other to 946,511 Gemany Aug. 2, '1956 form a single axle extending completely 'across the hull. I V V References Cited in the file of this patent OTHER REFERENCES z: I UNITED STATES PATENTS 10 Ser. No. 268,421, Tietjens (ARC), published May 1,227,784 Hewitt May 29, 1917 11, 19 3- I 2,720,180 Schentel Get. 11, 1955 Yachting, vol. 103, N0. 4, April 1958 (pages 69, 70,:

2,771,051 schertel NOV. 20, 19 6 71 relied on).

Claims

1. IN A SHIP HAVING A HULL, A SELF-ADJUSTABLE HYDROFOIL WING UNIT COMPRISING, AN AXLE ADAPTED TO BE ROTATABLY MOUNTED IN SAID HULL FOR ROTATION ABOUT A HORIZONTAL AXIS, AN ARM MOUNTED ON SAID AXLE AND DEPENDING DOWNWARDLY AND REARWARDLY OF SAID HULL, A FIRST WING MOUNTED ON THE ARM AT THE MIDDLE PORTION OF SAID WING, SAID FIRST WING EXTENDING OUTWARDLY AND UPWARDLY OF SAID ARM AND FORWARDLY RELATIVE TO SAID HULL AND INWARDLY AND DOWNWARDLY OF SAID ARM AND REARWARDLY RELATIVE TO SAID HULL, A FIN CONNECTED BETWEEN THE UPPER FORWARD END OF SAID FIRST WING AND SAID ARM WHERE IT IS MOUNTED ON SAID AXLE, SAID ARM EXTENDING BELOW SAID FIRST WING, A SECOND WING MOUNTED ON THE END OF SAID ARM AND EXTENDING HORIZONTALLY, A FURTHER ARM MOUNTED ON SAID AXLE, AND REACTION MEANS CONNECTED TO SAID FURTHER ARM FOR EXERTING A REACTION FORCE THEREON TO ROTATE SAID FURTHER ARM AROUND THE AXLE IN A DIRECTION OPPOSED TO THE DIRECTION SAID ARM WILL BE ROTATED BY THE LIFT FORCES EXERTED ON SAID WINGS.