US3558081A

US3558081A - Airborne vehicles

Info

Publication number: US3558081A
Application number: US800936A
Authority: US
Inventors: Paul E Williams
Original assignee: Airmarine Corp
Current assignee: Airmarine Corp
Priority date: 1969-02-20
Filing date: 1969-02-20
Publication date: 1971-01-26
Anticipated expiration: 1988-01-26

Abstract

An airborne vehicle provided with a rotor assembly consisting of a hub and a plurality of blades spaced axially of the hub, each blade including an inboard section having a forwardly inclined torque vector and an outboard section having a rearwardly inclined torque vector, the chord of the inner section being greater than that of the outer section.

Description

United States Patent lnventor Paul E. Williams Purcellville, Va. Appl. No. 800,936 Filed Feb. 20, 1969 Patented Jan. 26, 1971 Assignee Airmarine Corporation Washington, D.C. a corporation of Delaware Continuation-impart of application Ser. No. 501,809, Oct. 22, 1965, now abandoned.

AIRBORNE VEHICLES 8 Claims, 20 Drawing Figs.

11.8. Cl .1 244/ 17.19, 416/19, 416/170, 416/198, 416/242 Int. CL; 1364c 27/06, B64c 1 Ill 8 Primary Examine'r-Milton Buchler Assistant Examiner-Paul E. Sauberer Attorney-Alexander B. Blair ABSTRACT: An airborne vehicle provided with a rotor assembly consisting of a hub and a plurality of blades spaced axially of the hub, each blade including an inboard section having a forwardly inclined torque vector and an outboard section having a rearwardly inclined torque vector, the chord of the inner section being greater than that of the outer section.

PATENIED JAN26 ran sum 1 or 6 INVENTOR. 841/1 5. MAL/4M5 ATTORNEYS.

PATENTEU JAN26 |97| SHEET 3 OF 6 INVENTOR. P401 .5. M14 M/WS ATTORNEYS.

PATENTED JAN26 l9?! SHEET 5 BF 6 INVENT OR. PMA 5. W/ZA/AMJ ATTORNEYS AIRBORNE VEHICLES CROSS REFERENCE TO RELATED APPLICATIONS This invention relates to airborne vehicles and comprises an improvement over US. Pat. No. 3,065,933 and is a continuation-in-part of my copending application Ser. No. 50l,809, now abandoned entitled Airborne Vehicles, filed Oct. 22, 1965. More specifically this invention relates to an improved rotor or propeller blade for helicopters or fixed wing aircraft and a mounting device therefor.

The aforementioned patent discloses a rotor blade for a helicopter in which the outboard section of the blade is upwardly inclined with respect to the horizontal for producing lift, drag and a resultant force thereof wherein the torque vector is inclined forwardly in the direction of the plane of rotation. Conversely the inboard section is configured to produce lift, drag and a resultant thereof wherein the torque vector is inclined rearwardly oppositely to the direction of rotation. The rotor blade described in this patent is mounted in a rotating shaft which provides a means to adjust the pitch of each of the blades.

It is an object of this invention to provide a helicopter blade which produces a large lift vector and a substantially zero resultant total torque vector thus providing a helicopter with great lift capacity and which requires no torque combatting rear propeller.

Another object of this invention is to provide a helicopter blade which takes advantage of the lower instantaneous velocity of the inboard section of the blade to enhance its lifting characteristics.

A more specific object of this invention is to provide a rotor blade for helicopters having an increased chord on the inner section thereof.

A still further object of this invention is to provide a helicopter blade having an inner section with an increased angle of attack adjacent the inner end thereof.

It is an object of this invention to provide a helicopter having an articulatable rotor assembly which may be manipulated to produce flight.

Another object of this invention is to provide a helicopter having a universally mounted rotor assembly which may be pivoted in order to control the motion of the vehicle.

A more specific object of the instant invention is to provide a helicopter having a rotor assembly which is pivotally mounted on two perpendicular axes.

A more specific object of this invention is to provide a helicopter having an articulatable rotor assembly interconnected with a tail rudder assembly to properly control the motion of the aircraft.

Another object of this invention is to provide a helicopter having an engine and drive assembly connected to a rotor housing, in which the rotor housing and engine are articulatably mounted to avoid the necessity of a flexible drive shaft.

Another more specific object of this invention is to provide a helicopter having a light weight, high power-to-weight ratio engine which may be mounted for universal movement along with an articulatable rotor assembly.

Another object of this invention is to provide a helicopter which utilizes a fiuoro carbon engine and a specially configured rotor blade.

It is another object of this invention to provide a toy helicopter having an articulatable rotor assembly.

A further object of this invention is to provide a toy helicopter having a gas operated motor directly connected to a rotatable rotor assembly.

A still further object of this invention is to provide a toy helicopter having a rotor assembly pivoted in a vertical longitudinal plane with respect to the body of the aircraft.

It is another object of this invention to provide a toy helicopter having magnetic means for manipulating an articulatable rotor amernbly.

A further object of this invention is to provide a toy helicopter having a light weight, high power-to-weight ratio gas operated engine.

Another object of this invention is to provide a blade for airborne vehiclcs which may be utilized on either a rotary wing aircraft or a fixed wing aircraft.

Other objects and advantages of the instant invention reside in the combinations of elements, arrangements of parts, and features of construction and operation. some of which will be apparent and some of which will be more fully pointed out hereinafter and disclosed in the accompanying drawings wherein there are shown preferred embodiments of this inventive concept.

IN THE DRAWINGS FIG. I is a side elevational view of a helicopter showing the rotor blade, the engine and engine mounting of the instant invention;

FIG. 2 is a front elevational view of the device of FIG. 1;

FIG. 3 is a longitudinal cross-sectional view of the helicopter of FIG. I taken substantially along line 3-3 thereof and viewing in the direction of the arrows;

FIG. 4 is a cross-sectional view of the helicopter of FIG. I taken substantially along line 4-4 thereof and viewing in the direction of the arrows, showing the engine and engine mounting of the instant invention;

FIG. 5 is a cross-sectional view of the helicopter of FIG. 1 taken substantially along line 5-5 thereof and viewing in the direction of the arrows showing the mounting of each rotor blade on the power shaft;

FIG. 6 is an enlarged rear view of one of the rotor blades shown in FIG. I;

FIG. 7 is a top plan view of the rotor blade of FIG. 6;

FIG. 8 is a transverse sectional view of one portion of the rotor blade of FIG. 7 taken substantially along line 8-8 thereof and viewing in the direction of the arrows;

FIG. 9 is another transverse cross-sectional view of the blade of FIG. 7 taken substantially along line 99 thereof and viewing in the direction of the arrows;

FIG. 10 is an enlarged side view of the connections between the rotor blades and the power shaft as seen from plane 10-10 of FIG. 5, viewing in the direction of the arrows;

FIG. 11 is a longitudinal cross-sectional view of the engine and engine mounting of FIG. 4 taken along line 11-11 and viewing in the direction of the arrows, certain parts being omitted for clarity of illustration;

FIG. 12 is a schematic view of a control system used to direct the movement of the helicopter of the instant invention;

FIG. 13 is a top plan view of an alternate form of engine and engine housing used with the helicopter of the instant inventron;

FIG. 14 is a side elevational view of a toy helicopter embodying the principles of the instant invention;

FIG. 15 is a front view of a remote control station through which an operator may manipulate the helicopter of FIG. 14 through a coaxial cable or the like;

FIG. 16 is a top plan view of the helicopter of FIG. 14, the rotor blades being removed for clarity of illustration;

FIG. 17 is a front elevational view of a fixed wing aircraft utilizing the rotatable blade of the instant invention as a propeller; and

FIGS. l8, l9, and 20 are diagrammatic views illustrative of principles of operation hereinafter described.

Referring now to the drawings in detail, and particularly to FIGS. I to 13 inclusive, wherein like reference characters designate like elements throughout the several views thereof, there is indicated generally at 10 a helicopter comprising a frame type body shown generally at 12, an operator's station indicated generally at 14, a tail rudder generally shown at I6,

and an engine and engine mounting assembly indicated generally at 18 and a rotor and rotor blade assembly shown generally at 20.

Helicopter body I2, which, as illustrated, is of the frame type, but which may be of any other type, comprises a centrally disposed l-beam 22 which lies along the longitudinal axis of helicopter l0 and which has secured adjacent, but spaced from, its rearward end, a vertically disposed l-beam 24. A right-angle triangular brace 26 is utilized to rigidify the connection between l-

beams

22, 24, which connection is customarily effected by welding.

Secured transversely to the rearward end of I-bcam 22 is a wheel-carrying U-shaped channel member 28 as will be more fully explained hereinafter. A forwardly and inwardly extending tubular brace 30 connects the outer ends of wheel-carrying member 28 to the upper portion of vertical I-beam 24 for purposes of rigidity.

The rear section of helicopter comprises a pair of elon

gated plates

32, 34 which are secured at their forward ends to I-beam 24 as shown in FIG. 3 and which straddle and are secured to a diagonal I-beam 36 which is secured to I-beam 22 rearwardly of vertical I-beam 24.

As previously indicated, U-shaped wheel-carrying member 28 has positioned on the outer ends thereof a wheel assembly indicated generally at 38 comprising a shock absorbing connection 40 perpendicularly secured to an axle 42 on which is rotatably mounted a conventional wheel 44. A steering wheel indicated generally at 46 is rotatably mounted in the forward end of I-beam 22 and comprises a rotatable shock absorbing connection 48, the lower end of which carries a steering fork 50in which is rotatably mounted a conventional wheel 52.

operators station 14 comprises a horizontal platform 54 secured to l-beam 22, a suitable operators seat 56 and a control mechanism indicated generally at 58. Control mechanism 58 comprises a steering post 60 which operably connects ground wheel 52 to an operator's steering wheel 62 through a suitable control box 64 as more fully explained hereinafter. Mounted in front of steering wheel 62 and within the view of an operator is a control panel 66 which may carry instruments 68 for indicating air speed, altitude, engine speed and the like.

It should be apparent that all necessary controls are placed in operators station 14 so that an operator may properly manipulate the tail rudder 16, the engine and engine mounting assembly 18, and the rotor and rotor blade assembly as more fully explained hereinafter.

Tail rudder assembly 16 comprises a first vertical plate 70 which may be a major segment of a circle and which is fixedly secured to

plates

32, 34 of body 12 as shown in FIG. 3. Pivotally mounted by vertical pivot pins 72 on the rearward edge of plate 70 is a second vertical plate 74 which may be a minor segment of a circle and which has perpendicularly secured thereto a lever arm 76 which is connected to a first power means indicated generally at 78.

Power means 78 comprises a conventional electric motor 80 having a drive shaft 82 on the end of which is secured a lead screw portion 84. Threadably mounted on lead screw 84 is a collar 86 which is pivotally mounted by a vertical pin 88 to lever arm 76. An operator in operator station 14 may actuate an appropriate electrical device to actuate motor 80 so that screw 84 is threaded in and out of collar 86 thereby manipulating rudder 74 in order to aid in the turning of helicopter 10 to the left or to the right.

An important feature of the instant invention resides in the engine and engine mounting assembly 18 which comprises a universal mounting connection indicated generally at 90 and a prime mover shown generally at 92 mounted therein. Universal mounting connection 90 comprises an outer gimbal frame shown generally at 94 having a forward transverse section 96, a pair of parallel rearwardly extending side edges 98, a pair of rearwardly diverging side edges 100, a pair of parallel rearwardly extending edges 102 and a rear transverse end wall 104. As shown in FIG. 4 outer gimbal frame 94 is thus configured to provide an enlarged rearward area so that maintenance personnel may readily service prime mover 92.

End walls

96, 104 are apertured along the longitudinal axis of outer frame 94 to provide openings into which a pair of pivot pins 110, 112 are placed. Pivot pins 110, 112 of outer frame 94 are mounted in a pair of channel blocks 114, 116 which are fixedly mounted on vertical l-beam 24 and diagonal I-beam 36 respectively on the longitudinal axis of helicopter 10. Outer frame 94 also includes a pair of transversely aligned apertures 118 in sidewalls 98 positioned at the approximate center of gravity of engine and engine mounting assembly 18 and rotor blade assembly 20.

An inner gimbal frame indicated generally at 120 comprises parallel sidewalls 122 with a pair of end walls 124 perpendicular thereto to provide a rectangular configurationed frame. Mounted on sidewalls 122 is a pair of aligned pivot pins 124', 126 for engagement with apertures 118 of outer frame 94.

A pair of actuating devices indicated generally at 130, 132 which may be substantially identical to pivoting means 78 as shown in FIG. 3, are provided to manipulate universal connection 92 as more fully explained hereinafter. As shown in FIG. 3, actuating means comprises an electrical motor 134 vertically secured by a bracket 136 to transverse channel member 28 and has a substantially vertical threaded lead screw 138 in threaded engagement with a collar 140 which is secured to sidewall 98 of gimbal frame 94 by a pivot connection 142. In a like manner, actuating means 132 comprises an electric motor 144 secured to vertical I-beam 24 by a bracket 146, a vertical threaded lead screw 148 secured in collar 150 which is pivotally secured to inner gimbal frame 120 by pivot connection 152 forwardly of

pivot axis

124, 126.

In the operation and manipulation of universal connection 90, an operator may manipulate steering wheel 62 at operators station 14 to advance or withdraw threaded screw 138 of actuating device 130 as indicated in FIG. 12 in order to pivot outer gimbal frame 194 about

longitudinal axis

110, 112. In a like manner, an operator may advance or withdraw lead screw 148 of actuating means 132 in order to pivot inner gimbal frame about transverse

horizontal axis

124, 126 in order to position a rotor and rotor blade assembly 20 in any desirable position as more fully explained hereinafter. In addition to operating each of actuating means 78, 130 and 132 individually, it has been found advantageous to electrically connect actuating means 78 and 130 within control box 64 so that both will actuate simultaneously to facilitate banking and turning of helicopter 10.

As shown in FIG. 4, engine 92 may comprise an engine of any convenient type, such as an internal combustion engine, a turbine, or a nuclear powered engine, fixedly mounted to inner frame 120 having a drive shaft 154 arranged along the longitudinal axis of inner frame 120 operably connected to a clutch means or fiuid coupling 156 of any desired configuration. Drive connection 156 is operably connected to a driven shaft 158 which is connected by a drive mechanism indicated generally at 160 to a rotatable shaft 162 which carries a series of rotor blades generally indicated at 164.

Dn've mechanism 160 comprises a casing 166 which is secured to sidewalls 122 of inner frame 120 by a pair of transverse plates 168, 170 Casing 166 carries a first bearing 172 which rotatably mounts shaft 158 therein. A worm gear 174 is fixedly secured on the end of rotatable shaft 158 in operative engagement with a worm wheel 176 which is secured to a depending shank 178 of rotatable shaft 162. A pair of

bearings

180, 182 rotatably mount shank 178 in casing 166 as shown in FIG. 11.

It is thus seen that engine 92 rotates shaft 154 and 158 in the conventional manner which operates through drive mechanism or differential 160 to impart a rotating movement to shaft 162; Suitable controls may be placed at operator station 14 so that an operator may start engine 92, manipulate fluid coupling 156 or regulate the speed of engine 92;

It has been found greatly advantageous to use a prime mover of the type disclosed in US. Pat. No. 2,918,982 and a slightly modified engine mounting in the present devicein lieu of a conventional internal combustion engine. It has been found that the engine disclosed in the aforementioned patent has a high power-toweight ratio thus enhancing the use of the universal mounting in conjunction therewith to avoid the need of a flexible drive shaft as is required in conventional helicopters. It has been determined, for example, that a gas operated motor of the type shown in this patent weighing on the order of 10 pounds will produce about 150 hp.

As shown in FIG. 13 an alternate engine and engine mounting assembly 184 is provided which comprises a universal mounting connection indicated generally at 186 and a prime mover indicated generally at 188 of the type disclosed in U.S. Pat. No. 2,918,982. Universal mounting connection 186 comprises an outer gimbal frame 190 which is rectangular in cross section and which is pivotally mounted as at 192, 194 along its longitudinal axis in much the same manner that mounting connection 90 is mounted on frame 12. An inner gimbal frame 196 is of like configuration and is pivotally mounted on

journals

198, 200 adjacent the center of gravity of engine and engine mounting assembly 184 and rotor assembly 20.

Manipulative devices

130, 132 may be connected with engine mounting assembly 184 for manipulation thereof as previously mentioned.

Prime mover 188 will be discussed only generally, the previously mentioned patent being relied upon for completeness of disclosure. Prime mover 188 comprises a gas operated motor 202 which is connected by flexible high pressure hoses 204,

206 to a throttle operated valve 208. Valve 208 is connected by inlet and exhaust hoses 210, 212 to a vaporizer and condenser unit indicated generally at 214. As disclosed in the aforementioned patent a quantity of high pressure gas is emitted from a vaporizer, delivered by appropriate conduits to gas operated motor 202 with the resultant exhaust gases being reclaimed by condensation. As indicated in FIG. 13 throttle operated valve 201 and condenser and vaporizer unit 214 may conveniently be mounted on the frarne12 of helicopter in order to minimize the weight carried by engine mounting assembly 18, although these devices may be mounted on frame 18.

Rotor assembly 20 comprises a normally vertical rotatable shaft 162 drivingly connected to motor 92 as hereinbefore explained and rotatably mounted in ajoumal generally indicated at 216 secured on inner frame 120. As shown in FIG. 11, journal 216 comprises a transverse plate 218 secured to inner frame 120 by rivets or the like 220 and an upstanding shaftreceiving sleeve 222 secured by rivets or the like 224 to transverse plate 218.

As shown in FIGS. 1 and 2, the upper end of shaft 162 may be equipped with integrally formed blade holders 226 which are equally spaced about the periphery of shaft 162 and are vertically spaced. Fixedly secured in each of blade holders 226 is a rotor blade indicated generally at 164, the configuration of which will be more fully explained hereinafter. Horizontally aligned with each of blade holders 226 in shaft 162 is an aperture in which is secured a counterweight indicated generally at 230 comprising a rod 232 and a radially positioned weight 234 which acts to substantially balance each of blades 214.

Alternatively, blades 164 and counterweights 230 may be secured to shaft 160 as shown in FIGS. 5 and 10 wherein a sleeve 236 is secured about the upper periphery of shaft 160 which carries a blade and counterweight holding means indicated generally at 238. Holding means 238 comprises a substantially rectangular lock 240 having a centrally disposed aperture 242 which is fixedly secured to sleeve 236, a rod receiving portion 244 receiving counterweight 230 and a diametrically opposed blade holder shown generally at 246.

Blade holder 246 comprises a horizontal aperture 248 for receiving blades 164 and a series of vertically and horizontally disposed

bolts

250, 252 for securing blade 164 therein.

Blade 164 comprises an inner section indicated generally at 254 and an outer section indicated generally at 256 of generally the same configuration as that shown in U.S. Pat. No. 3,065,933, the disclosure of which is incorporated by reference herein. As disclosed in FIG. 9 of the aforementioned patent, the center line of outer section 256 may describe a 10 angle with the center line of inner section 254, although a straight blade may be used. The separation of inboard and

outboard sections

254, 256 occurs between the 38 percent and 52 percent station as measured from the tip of outer section 256. Inboard section 254 describes dihedral angle of between 7 and 12 with respect to the horizontal while outward section 256 is substantially horizontal when mounted on shaft 160.

It is a characteristic of rotating bodies that the outermost radial end has the highest instantaneous velocity with instantancous velocity decreasing inwardly along a radial line. It has been found that the rotor blade disclosed in U.S. Pat. No. 3,065,933 not only substantially completely eliminates torquing of the helicopter body in a direction opposite to the rotation of blade 14 as was recognized in the aforementioned patent, for example, column 1, lines 35-80 and column 4, lines 72-74, but also tends to induce rotation of the helicopter body in the same direction as the direction of rotation of the blades.

This torque factor may be explained as follows:

It is known that the shape and thickness of any airfoil section determines the magnitude of the lift, drag and the resultant of the lift and drag. These are expressed in terms of dimensionless ratios as:

C,, Lift Coefiicient C D Drag Coefficient.

Consequently based on the Newton law of force where F (Ma), we may set up a vector analysis (Drzwiecki Blade Element Theory) of the forces occurring on a blade (see FIGS. 19 and 20) element at any station along the radius as follows:

3. L I (pv RdrC s) 4. D I v kmc s In the above and following explanations and equations the following symbols are defined in the following terms:

a Aerodynamic Pitch Geometric Pitch B Pitch Angle R Blade Radius 100 percent R 100 percents R dr= Derivative of the Radius at any station approaching 100 percent R as a limit dT Thrust at Rdr dD Drag in Pounds at Rdr dR Resultant of the thrust, lift, torque and drag.

d0 Torque V Rotational Velocity (feet per sec.)

Rdr is identified by station and is expressed in terms of percent of Radius. The variation of velocity is a function of the radius at Rdr. It is obvious that the velocity (V) increases as the radius approaches 100 percent R Where F Ma M Mass. for air it is defined in slugs (a) =V acceleration In FIG. 19, the downwash or vortex sheet (a) is down in accordance with Prandtl. The lift, drag and resultant are resolved into thrust and torque. The torque (b) acting back is given a positive sign. It is to be noted that the mechanical torque (Q should be added to the aerodynamic torque because they both act in a positive direction.

At the outboard portion of the blade, the wind direction (c) is up so that the aerodynamic angle of attack, or pitch (01) (d) is small.

The Falling Plate Theory" accounts for this condition and may briefly be described as follows:

Assume a symmetrical flat plate made of a material having sufficient energy to resist bending and deformation due to the air loading as it falls. The plate is rigid and has weight.

A particle d moves in reaction upward opposite in direction to the falling plate. The particle may be considered as being a displacement with turbulence in the elastic medium (AIR) as a vehicle of transmission.

The elastic medium may be conceived asst succession of ad- I joining particles each initially (before movement of the plate) as being in an equilibrium position. The particle is subject to a restoring force as a result of attraction or repulsion by adjacent particles. These, in turn, are subjected to reaction forces exerted by the original particle. When the particle (dS) is given a sudden displacement (dV) by the source, this particle exerts forces on its immediate neighbors which experience displacements, and imposing on the next nearest particle at the source causes a displacement wave expanding outward and contracting inward as the particle (dS) returns to an equilibrium condition.

This law applies to translational motion also. It is noted that the plate must displace a mass (M) equivalent to its own density (Q) and weight (W) at a rate equal to or greater than its falling rate (d-V,). Two factors must be observed here now; these are:

a. The expansion waves obey the third law of Newton as the waves initially radiate away from center, they finally radiate inwards toward the center as surface S moves downward (dV,).

b. The particle is not pushed down as the surface (S) moves (dV,) but rather it moves up (d+V,) as the surface moves (dV,.). Thus the upward component (d-l-V occurs in reaction against the plate in the air similar to the action of the hydrostatic pressure against the hull of a boat in buoyant equilibrium.

It must be concluded therefore that there must be an upward component of the air mass in reaction which is equal and opposite to the downward action, imposed upon the air mass by means of a mechanical body.

The vortex sheet is upward and therefore not in accordance with Prandtl. His theory is limited by the local Perturbation principle viz., it is assumed that the flow conditions are uniformly the same all the way across the radius. However, it has been discovered that this is not the case; local flow conditions must not only be considered, but the disposition of the vortex sheet must be taken into account. Resolving these sheets into fields, it becomes clear that the vortex sheet of FIG. 20 is vertical. However as this field is followed it is found that it eventually resolves itself into a downwash. There is thus a delayed vortex" and the laws of Newton and Prandtl are satisfied. Therefore there is left over this geometrically negative pitch section. Since the lift is valid, the force diagram of FIG. 20 is valid. It is clear then that with the resultant of the lift inclined forward, the torque force acts forward. This may fit into the

equations

3 and 4 where the sign of the torque for this outboard section is minus.

The torque forces may then be summarized as follows:

5. ZIY F Rdn, Rdr where r is 43 percent of the radius where the pitch angle (3) is positive and the forces are represented in the force diagram Figure 20.

and r l is'the range between station 43 and 100 where the blade angle (3) is progressively negative.

It is observed that the center of the positive torque force may lie somewhere around Station 25. The center of the negative (forward acting) torque force is around The centroid of these forces lying on Rdr and Rdr the moment of torque is:

adding osam) O This discovery has been proved by actual tests in that the rotor system freely mounted on a vertical axis will autorotate into an air stream.

It has been found that the lift produced by a rotor blade such as shown in the aforementioned patent, may be increased considerably while the torque tending to rotate the helicopter may be substantially totally eliminated by modifying the inner section of the rotor blade as disclosed herein. As shown in FIGS. 6 to 9 inclusive, both the chord and the pitch of inner section 254 of blade 164 may be selectively altered to achieve these results. The increase in the chord of section 254 will produce increased lift in direct proportion to the increase in the area thereof; however, no perceptible increase in lift was noted when inner section 254 was less than 2 percent larger than outer section 256. Furthermore. the relatively slow instantaneous velocity of the inner end of section 254 allows the use of a much greater pitch angle, thus generating additional lift without the production of a corresponding amount of aerodynamic torque. It has been found that a maximum pitch angle of about 48 may be used with the angle diminishing in an outward direction along blade section 254.

As shown in FIG. 8, inner section 254 of blade 164 describes a positive pitch angle with an upper smooth surface 258 and a lower smooth surface 260 configured in the manner of a conventional airfoil. A structural brace indicated generally at 262 extends radially of inner section 254 between upper and

lower surfaces

258, 260. Any conventional lightweight structural material may be placed in the inner volume ofinner section 254.

As shown in FIG. 9 outer section 256 of blade 164 describes a negative pitch angle with an upper smooth surface 264 and a lower smooth surface 266 being configured in the manner of an inverted airfoil as shown in the aforementioned patent. A structural brace indicated generally at 268 joins structural brace 262 and provides the main support member of blade 164.

Referring now to FIGS. 14 and 16 inclusive, there is indicated generally at 270 a toy helicopter comprising an encased body indicated generally at 272, a motor and motor housing assembly indicated generally at 274 suitably mounted in body 272, a rotor and rotor assembly shown generally at 276, which is of smaller similar configuration to rotor assembly 20, operatively connected to motor and motor housing 274 and a control unit indicated generally at 278.

Body 272 comprises a metal or plastic envelope having suitable

ground engaging wheels

280, 282 dependingly secured therefrom. Body 272 comprises a tail section 284 on which is mounted a rudder assembly indicated generally at 286 of similar configuration to that previously discussed.

Engine and engine mounting assembly 274 comprises a gim bal frame indicated generally at 288 providing an annular ring 290 which is pivotally secured on a transverse axis by journals 292 affixed to the interior of body 272. Gimbal frame 288 also includes a bracket 294 secured by any conventional means to body 272 providing a vertical slot in which resides a pin 296 having an enlarged head 298 which coacts with journals 292 to insure that engine assembly 274 and rotor assembly 276 will pivot in a vertical longitudinal plane with respect to helicopter body 272.

Engine and engine mounting assembly 274 also includes a gas operated motor 298 which is fixedly secured to the interior of annular ring 290 and includes a high pressure inlet connection 300 and an exhaust connection 302 extending through annular ring 290, all as more fully pointed out hereinafter.

Although any number of means may be provided to manipulate gas operated motor 298 about transverse axis 292, one convenient means is to provide motor 298 with a nomagnetizable casing with a magnetically active Strip 304 secured on the outer periphery thereof adjacent a series of

electromagnets

306, 308, 310 which are connected to a battery as more fully explained hereinafter. As shown in FIG. 14

electromagnets

306, 308, 310 are arranged on an arc the radius of which is journal 292. By selective actuation of any of

magnets

306, 308, 310, ferric strip 304 will be attracted thereto thus pivoting motor 298 about pivot axis 292.

Gas operated motor 298 has an output drive shaft 312 which is preferably directly coaxially connected to rotor assembly 276 but which may be connected to rotor assembly 276 through a gear train. Thus the generation of rotary movement of output shaft 312 will operate rotor assembly 276 to propel helicopter 270. As mentioned previously, the pivotal movement of motor 298 about pivot axis 292 by the selective actuation of

electromagnets

306, 308, 310 will incline rotor assembly 276 forwardly through an elongated slot 314 in body 272 to give helicopter 270 a forward component of flight.

An important feature of the instant invention is the use of a fluid motor such as described in US. Pat. No. 2,918,982 in toy helicopter 270. One important advantage of such a motor is that it may be miniaturized to be fitted within a toy helicopter and yet retain a favorable power-to-weight ratio upon miniaturization. For example, a motor weighing a few ounces has been found to develop one horsepower which is easily sufficient to manipulate rotor assembly 276 to give helicopter 270 powered flight.

Engine and engine mounting assembly 274 also includes a gas exhaust conduit 316 leading to a fluid trap 318 which is connected to a condenser coil indicated generally at 320. Connected to a condenser 320, in order to receive condensed liquids therefrom, is a vaporizer assembly 322 which is connected to a ground situated battery (not shown) by a series of electrical wires 324 which may be wound on a single cable. Vaporizer 322 has an outlet 325 which is connected to high pressure inlet 300 of motor 298 by a high pressure conduit 326.

Although one placement of the elements of the fluorocarbon engine has been disclosed, it should be evident that the components may be differently situated within body 272 to provide a balanced aircraft, to avoid heating condenser 320 with vaporizer 322 and to provide an air inlet to facilitate the condensing of liquids in condenser 320.

As intimated previously,

electromagnets

306, 308, 310 are connected by a series of electrical wires 326 to a ground situated control panel and power source indicated generally at 278. Control panel 278 will include a conventional chemical battery, an on-ofl' switch 327 for shutting off power from the battery, and a control handle 328 which may be utilized to selectively energize

electromagnets

306, 308, 310 to position the rotor assembly 276 in the desired location. A throttle handle 330 is provided to control the energy input to vaporizer 322 to control the amount and pressure of fluid exhausting therefrom. Furthermore, a magnetically actuable device may be placed adjacent rudder 286 for actuation by a suitable control switch in panel 278.

In the operation of toy helicopter 270, on-off switch 327 is moved to the on" position with handle 330 being placed at a high rating to begin vaporization of the fluorocarbon liquid in vaporizer 322. Upon the creation of sufi'icient pressure and volume of gases therein, the gases will flow through conduit 326 into gas operated motor 298 to rotate drive shaft 312 thus imparting rotary motion to assembly 276 giving helicopter 270 a vertical flight capacity. Handle 328 is initially held in a position which actuates electromagnet 306 to keep rotor assembly 270 in a vertical position. when it is desired to impart a forward component of motion to toy helicopter 270, it is necessary only to manipulate handle 328 to another position which will actuate electromagnet 308 and deactuate electromagnet 306. Magnetizable strip 304 will then be attracted rearwardly and rotor assembly 276 will assume a slightly forwardly tilted position thus creating the forward component of movement. If

additional forward speed is desired, handle 328 may be manipulated to energize eleetromagnet 310 to tilt rotor assembly 276 forwardly to provide a greater inclination of assembly 276. The speed or hovering capacity of toy helicopter 270 may be controlled through the manipulation of control handle 330 which regulates power input to vaporizer 322 thus controlling the amount and pressure of gas entering motor FIG. 17 discloses a conventional light weight fixed wing airplane indicated generally at 332 which is conventional in all respects except for the utilization of a propeller indicated generally at 334 of the same configuration as that utilized on helicopter 10 and toy helicopter 270: Inasmuch as rotor assembly of helicopter 10 produces an extraordinary amount of lift, rotor assembly 334 will produce a like amount of propelling force.

It is now seen that there is herein provided an improved helicopter and blade therefor fulfilling all the objects of this invention and others including many advantages of great practical utility and commercial importance.

I claim:

I. A helicopter comprising: i

a body having a longitudinal axis;

a rotor assembly including a central, normally vertical rotatable shaft, a hub secured to said shaft, and at least two axially spaced rotor blades operably secured to and extending away from said hub;

a prime mover operably connected to said rotor blade comprising a vertical drive shaft parallel to said rotatable shaft and operably secured thereto for rotating said shaft;

means mounting said rotor assembly and said prime mover on said body for pivotal movement in a vertical plane parallel to a vertical plane through said longitudinal axis of said body;

each rotor blade comprising a radially inner portion having a chord and a radially outer portion having a chord, the juncture of the inner and outer sections being smooth and unobstructed, the inner portion having a positive pitch angle and at least the outer end of the outer portion having a negative pitch angle, said chord of said inner portion being substantially greater than said chord of said outer portion;

said prime mover comprising a gas operated motor having an inlet and an outlet, a liquid vaporizer, means connecting said vaporizer and said inlet, a condenser, means connecting said outlet and said condenser, means connecting. said condenser and said vaporizer, and means for controlling the flow of a fluid through said prime mover; and

said prime mover also including a nonmagnetizable housing having a magnetizable strip on the periphery thereof, means for pivoting said mounting means in said vertical plane including a series of selectively energizable magnetic means positioned on said body adjacent said prime mover for selectively attracting said magnetizable strip and said prime mover to move said rotor assembly in said vertical plane.

2. A rotatable blade comprising:

an inner section having a root, a leading edge, a trailing edge and a chord;

an outer section integral with said inner section: having a tip, a leading edge, a trailing edge and a chord;

the leading edge of said outer section forming an obtuse angle with the leading edge of said inner section;

said inner section having a positive pitch angle;

the pitch angle of said inner section decreasing from the root to its juncture with said outer section;

said outer section curving from a slight positive pitch angle to a negative pitch angle adjacent its juncture with said inner section;

the negative pitch angle increasing progressively toward the tip, to reduce pressure and decrease turbulence at the tip and redirect air flow toward the inner section; and

the chord of said inner section being greater than the chord of the outer section to compensate for increased pressure due to increased speed of rotation of the outer section.

3. The structure of claim 2 wherein said chord of said inner portion is more than 2 percent greater than the chord of said outer portion.

4. The structure of claim 2 wherein said positive pitch has a maximum angle of about 48.

5. The structure of claim 2 wherein the chord of the inner section is substantially constant throughout a major portion of its length, and decreases sharply adjacent its juncture with said outer section,

the chord of the outer section being substantially constant to a point adjacent the tip.

6. A rotor structure including a hub having a plurality of blades thereon, the blades being offset relative to each other along the axis of rotation of the hub, each blade comprising:

an inner section having a root, a leading edge, a trailing edge and a chord;

an outer section integral with said inner section having a tip,

a leading edge, a trailing edge and a chord;

said inner section having a positive pitch angle;

the negative pitch angle increasing progressively toward the tip, to reduce pressure and decrease turbulence at the tip, redirect air flow toward the inner section, and obtain a cascade effect through the axially offset blades; and

7. A helicopter including a fuselage, a rotor, and a tail, said rotor comprising a hub, a plurality of vertically superposed radially offset blades to provide a cascade effect, each blade comprising:

an inner section having a root, a leading edge, a trailing edge and a chord;

an outer section integral with said inner section having a tip,

a leading edge, a trailing edge and a chord;

the leading edge of said outer section forming an obtuse angle with the leading edge of said inner section; said inner section having a positive pitch angle; the pitch angle of said inner section decreasing from the root to its juncture with said outer section; said outer section curving from a slight positive pitch angle to a negative pitch angle adjacent its juncture with said inner section; the negative pitch angle increasing progressively toward the tip, to reduce pressure and decrease turbulence at the tip and redirect air flow toward the inner section; and the chord of said inner section being greater than the chord of the outer section to compensate for increased pressure due to increased speed of rotation of the outer section to provide a substantially torque free rotor, eliminating the necessity for a tail rotor to compensate for torque. 8. The structure of claim 7 wherein thcjuncture of the inner section and the outer section is at substantially 43 percent of the length of the blade measured outwardly from the hub.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3558n8] D t d January 1971 Paul F. Williams Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet cancel "[73] Assignee Airmarine Corporation, Washington, D. C. a corporation of Delaware".

Signed and sealed this 6th day of February 1973.

(512M) Attest: I

EDWARD M. FLETCHIERJR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-IOSD [10-59] 5-,

Claims

1. A helicopter comprising: a body having a longitudinal axis; a rotor assembly including a central, normally vertical rotatable shaft, a hub secured to said shaft, and at least two axially spaced rotor blades operably secured to and extending away from said hub; a prime mover operably connected to said rotor blade comprising a vertical drive shaft parallel to said rotatable shaft and operably secured thereto for rotating said shaft; means mounting said rotor assembly and said prime mover on said body for pivotal movement in a vertical plane parallel to a vertical plane through said longitudinal axis of said body; each rotor blade comprising a radially inner portion having a chord and a radially outer portion having a chord, the juncture of the inner and outer sections being smooth and unobstructed, the inner portion having a positive pitch angle and at least the outer end of the outer portion having a negative pitch angle, said chord of said inner portion being substantially greater than said chord of said outer portion; said prime mover comprising a gas operated motor having an inlet and an outlet, a liquid vaporizer, means connecting said vaporizer and said inlet, a condenser, means connecting said outlet and said condenser, means connecting said condenser and said vaporizer, and means for controlling the flow of a fluid through said prime mover; and said prime mover also including a nonmagnetizable housing having a magnetizable strip on the periphery thereof, means for pivoting said mounting means in said vertical plane including a series of selectively energizable magnetic means positioned on said body adjacent said prime mover for selectively attracting said magnetizable strip and said prime mover to move said rotor assembly in said vertical plane.

2. A rotatable blade comprising: an inner section having a root, a leading edge, a trailing edge and a cHord; an outer section integral with said inner section: having a tip, a leading edge, a trailing edge and a chord; the leading edge of said outer section forming an obtuse angle with the leading edge of said inner section; said inner section having a positive pitch angle; the pitch angle of said inner section decreasing from the root to its juncture with said outer section; said outer section curving from a slight positive pitch angle to a negative pitch angle adjacent its juncture with said inner section; the negative pitch angle increasing progressively toward the tip, to reduce pressure and decrease turbulence at the tip and redirect air flow toward the inner section; and the chord of said inner section being greater than the chord of the outer section to compensate for increased pressure due to increased speed of rotation of the outer section.

4. The structure of claim 2 wherein said positive pitch has a maximum angle of about 48*.

5. The structure of claim 2 wherein the chord of the inner section is substantially constant throughout a major portion of its length, and decreases sharply adjacent its juncture with said outer section, the chord of the outer section being substantially constant to a point adjacent the tip.

6. A rotor structure including a hub having a plurality of blades thereon, the blades being offset relative to each other along the axis of rotation of the hub, each blade comprising: an inner section having a root, a leading edge, a trailing edge and a chord; an outer section integral with said inner section having a tip, a leading edge, a trailing edge and a chord; the leading edge of said outer section forming an obtuse angle with the leading edge of said inner section; said inner section having a positive pitch angle; the pitch angle of said inner section decreasing from the root to its juncture with said outer section; said outer section curving from a slight positive pitch angle to a negative pitch angle adjacent its juncture with said inner section; the negative pitch angle increasing progressively toward the tip, to reduce pressure and decrease turbulence at the tip, redirect air flow toward the inner section, and obtain a cascade effect through the axially offset blades; and the chord of said inner section being greater than the chord of the outer section to compensate for increased pressure due to increased speed of rotation of the outer section.

7. A helicopter including a fuselage, a rotor, and a tail, said rotor comprising a hub, a plurality of vertically superposed radially offset blades to provide a cascade effect, each blade comprising: an inner section having a root, a leading edge, a trailing edge and a chord; an outer section integral with said inner section having a tip, a leading edge, a trailing edge and a chord; the leading edge of said outer section forming an obtuse angle with the leading edge of said inner section; said inner section having a positive pitch angle; the pitch angle of said inner section decreasing from the root to its juncture with said outer section; said outer section curving from a slight positive pitch angle to a negative pitch angle adjacent its juncture with said inner section; the negative pitch angle increasing progressively toward the tip, to reduce pressure and decrease turbulence at the tip and redirect air flow toward the inner section; and the chord of said inner section being greater than the chord of the outer section to compensate for increased pressure due to increased speed of rotation of the outer section to provide a substantially torque free rotor, eliminating the necessity for a tail rotor to compensate for torque.

8. The structure of claim 7 wherein the juncture of the inner section and the outer secTion is at substantially 43 percent of the length of the blade measured outwardly from the hub.