Abstract: Locking mechanisms for backrest portions of (typically vehicle) seats are detailed. The mechanisms avoid any need to use conventional recline locks and thus simplify the designs of existing seats otherwise so equipped. The mechanisms also permit adjustment of the positions of the backrests relative to the bases prior to deployment and allow for tolerances as well.

Abstract: An electro-hydraulic thrust reverser lock actuation system includes a hydraulic fluid source and a lock actuator assembly that is configured to selectively pressurize the hydraulic fluid. The lock actuator assembly is adapted to receive a lock control signal and, in response, pressurize the hydraulic fluid in the hydraulic fluid source. One or more lock assemblies are in fluid communication with the hydraulic fluid source and are configured, in response to the hydraulic fluid pressurization, to move to one of a locked or an unlocked position.

Abstract: The aircraft has a main body 1 and a pair of sub bodies 4 and 5 positioned substantially in parallel with the main body 1 and respectively in both of the left and right sides of the main body 1. A canard 3 and main wings 8 and 9 each have a central portion fixed to the main body 1 and portions fixed respectively to the sub bodies 4 and 5, near left and right ends of the wings. Engines 6 and 7 are respectively mounted on outer surfaces of the sub bodies 4 and 5. The sub bodies 4 and 5 are thinner than the main body 1. The canard 3, which is positioned closest to the fore end of the aircraft, has a shorter wing span than the other wings. The sub bodies 4 and 5 contain fuel. The fuel is supplied to the engines 6 and 7 assuring high safety. The main wings 8 and 9 are positioned, shifted respectively forth and back relative to the main body 1. Therefore, stability is not impaired even if cargos are loaded into the main body over a wide range from the bow to the tail.

Abstract: A control surface drive system having a plurality of actuator assemblies are coupled to first and second supply lines and to a return line. The first and second supply lines are connected to a source of hydraulic fluid. At least one of the actuator assemblies has a hydraulic actuator movably connectable to an aircraft control surface. A flow control assembly is connected to the return line and to at least one of the first and second supply lines. A bypass line is in fluid communication with the first and second supply lines and positioned to recycle the hydraulic fluid from one of the first and second supply lines back into the other one of the first and second supply lines when the hydraulic actuator moves toward the first position. A computer controller operatively interconnects the plurality of actuator assemblies and the flow control assembly. It is emphasized that this abstract is provided to comply with the rules requiring an abstract.

Abstract: An orbital experiment system with different internal experiment locations within a reusable launch vehicle making daylong delivery trips to space. The experiments get access to the attributes of low earth orbit, the reusable launch vehicle's power and other subsystems. The experimenter utilizes uniform experiment trays having a uniform connector for connection to an experiment management unit mounted on the orbital vehicle. The experiment management unit provides power and data from the orbital vehicle related to the operation of the orbital vehicle and permits an experiment check simulation prior to integration into the launch vehicle. The uniform size and connectivity requirements provide low cost options for the delivery of an experiment into space and the return of the experiment from space.

Abstract: A vertical takeoff and landing aircraft (10) is provided including an aircraft fuselage (12). A plurality of hubs (20) are mechanically coupled to the fuselage (12) and are rotated by at least one engine (22). A plurality of tandem rotor/wings (14) are mechanically coupled to the plurality of hubs (20) and propel and lift the aircraft fuselage (12). A transitional lift wing (16) is mechanically coupled to the fuselage (12) and enables lift on the fuselage (12) during off-loading lift of the plurality of tandem rotor/wings (14). A main controller (24) is coupled to the plurality of tandem rotor/wings (14) and switches the plurality of tandem rotor/wings (14) between a vertical lift mode and a fixed wing mode. A method of performing the same is also provided.

Abstract: There is provided a store ejection system and method that use a pressurized non-pyrotechnic gas as the source of energy and transfer mechanism for jettisoning a store, such as from an aircraft. The ejection system includes an on-board pressure vessel for holding the pressurized gas with a releasable valve configured to hermetically seal the pressure vessel. The pressure vessel is releasably connected to system and the releasable valve is configured to be released after the pressure vessel is connected thereto so that the releasable seal hermetically seals the pressure vessel before the pressure vessel is connected to the pressure regulator. The ejection system also includes at least one actuation system and at least one pneumatically-driven jettison mechanism for releasably retaining the store.

Abstract: A vehicle, particularly a VTOL air vehicle, includes a duct carried by the vehicle frame with the longitudinal axis of the duct perpendicular to the longitudinal axis of the vehicle frame; a propeller rotatably mounted within the duct about the longitudinal axis of the duct to force an ambient fluid, e.g. air, therethrough from its inlet at the upper end of the duct through its exit at the lower end of the duct, and thereby to produce an upward lift force applied to the vehicle; and a plurality of spaced vanes pivotally mounted to and across the inlet end of the duct about pivotal axes perpendicular to the longitudinal axis of the duct and selectively pivotal to produce a desired horizontal control force in addition to the lift force applied to the vehicle. In a described preferred embodiment, the vanes are substantially parallel to the longitudinal axis of the vehicle frame. Various vane arrangements are disclosed for producing side, roll, pitch and yaw movements of the vehicle.

Abstract: Engine nacelles for use with aircraft. In one embodiment, an engine nacelle includes an inlet having an inlet aperture and an outlet having an outlet aperture. In one aspect of this embodiment, the engine nacelle further includes a first side portion, a second side portion, and a third side portion. The first side portion can extend at least generally between a first edge portion of the inlet aperture and a third edge portion of the outlet aperture. The second side portion can be offset from the first side portion and extend at least generally between a second edge portion of the inlet aperture and a fourth edge portion of the outlet aperture to define a first interior portion. The third side portion can be offset from the second side portion and extend at least generally from the second edge portion of the inlet aperture toward the fourth edge portion of the outlet aperture to define a second interior portion.

Abstract: A wireless landing gear monitoring system for an aircraft. The monitoring system includes a wireless, e.g. radio frequency (RF), hubcap transceiver powered by a rechargeable battery combined with a super-capacitor, all mounted to an inside surface of a wheel hubcap of the aircraft. Additionally, the system includes a permanent magnet generator (PMG) mounted to the inside surface of the hubcap that charges the battery when the wheel is rotating. The hubcap transceiver communicates with at least one distant, or remote, transceiver inside the aircraft, a tire pressure sensor mounted to a wheel rim, and a Hall-effect wheel speed transducer mounted to the hubcap. The tire pressure sensor uses an extremely low power wireless transmitter to communicate with the hubcap transceiver, which then sends wheel speed and tire pressure data to the distant transceiver.

Abstract: A rotor system that allows an aircraft to operate as a helicopter and as an airplane is disclosed. The invention incorporates an annular airfoil attached at the tips of the rotor blades. The rotor system stops and is secured from rotation for operation at high forward speeds. The annulus acts as the primary lifting surface in airplane mode at high speed. The rotor blades incorporate leading and trailing edge flaps for control in transitional and fixed wing flight modes.

Abstract: An aeroplane provided with noise-reducing means for reducing the noise level that is produced during a flight, in particular during the landing stage of the aeroplane, due to the presence of the landing gear of the aeroplane, said sound-reducing means comprising deflection means for deflecting an air flow away from the landing gear or at least from components thereof, characterized in that the deflection means comprise blowing means provided with a blowing element having at least one blowing nozzle for creating an air screen at the front side of the landing gear, or at least components thereof, from said at least one blowing nozzle.

Abstract: Vertical and/or lateral acceleration sensors are mounted in or on the engines or pylons of an aircraft to measure the vibrations induced by the operating dynamics of the engines. The sensors provide measured vibration signals to a controller that generates control signals in response to and dependent on the measured vibration signals. The control signals are provided to the aileron actuators, so as to actuate the ailerons appropriately to counteract and thereby reduce the engine-induced vibrations. Thus, the engine-induced vibrations acting on the fuselage are diminished and the passenger flight comfort is significantly improved.

Abstract: Apparatus for providing actuation power to an aircraft flight control surface. The apparatus includes a first actuator and a second actuator, where the second actuator has a bypass mode and an assist mode. The mode of the second actuator is determined by a load on the first actuator. When the second actuator is in the bypass mode, the first actuator provides the actuation power for the aircraft flight control surface. But, when the second actuator is in the assist mode, both the first and second actuators provide the actuation power for the aircraft flight control surface. Accordingly, the apparatus allows the flight control surface to be operated in a more efficient manner with less hydraulic flow being required.

Abstract: Various methods, apparatuses, and systems in which an electric-energy lifting panel levitates a user secured to the electric-energy lifting panel. The electric-energy lifting panel includes a first capacitive plate and a second capacitive plate having different geometric dimensions to generate a net-directional force. An ion conditioner ion enhances air around the first capacitive plate and the second capacitive plate.

Abstract: An improved aircraft includes a thrust source, a wing, and a boom functioning as a “free lever” and having a distal end upon which the thrust is acting and a proximal end about which the boom is freely rotatable to balance forces acting on the proximal and distal ends of the boom. The proximal end is pivotably mounted at or below the center of lift of the wing and above the center of mass of the aircraft. The distal end is located above the center of mass of the aircraft, when the lever is in the vertical position to establish a gravity pendulum, and forward of the center of drag of the aircraft, when the lever is in the horizontal position, to establish a drag pendulum. All transition flight is a resolution of the force vectors of the two pendulums. A director adjusts the vertical and horizontal thrust components of the propulsion system.

Abstract: A zero emissions (non-polluting) electric powered air vehicle having dual lifting surfaces comprised of a blended wing-body and a semi-annular upper wing, the blended body comprising a fuselage volumetrically sized to house a fuel supply and propulsion subsystems, electric motors driving propellers to provide forward thrust for propelling the aircraft, a nacelle for carrying passengers, a source of fuel for supplying an electrochemical process that generates electric power, a ballistic parachute for safe descent of the passenger cabin in an emergency, and landing gear has been described. The electrochemical process emission is water in one embodiment of the present invention. Another embodiment describes is an unmanned version of the present invention. A further embodiment describes an auxiliary power source from externally mounted PV cells that convert solar energy to electricity wherein the auxiliary power is used to recover fuel from the water emissions by an electrolytic process.

Abstract: In a method and apparatus for controlling the deployment of a towline connecting a mooring craft to an ejected object comprising the steps of monitoring velocity to determine when a point for optimum braking has been achieved and then engaging a brake system to retard deployment of the towline, a DC motor augments and controls the brake system. The DC motor further controls the retrieval of the object. A cutter mechanism uses a first blade to grip the towing cable to maintain tension thereon as a second blade cuts the cable. A spring biased boom in combination with spring biased fins on the ejected object rapidly deploys the object from its storage housing. A locking mechanism secures the deployment mechanism in a stable locked position upon the object reaching its fully extended position.

Abstract: The present invention utilizes a new aircraft tire or wheel which employs specially shaped vanes protruding from the tire or wheel. These vanes capture the slipstream, and cause the tire and wheel to rotate in the direction of aircraft travel. Another embodiment of the invention employs a ring with cast or molded vanes, which may be mounted to the wheel of existing landing gear without changing to the new type of tire. The desired rotational speed of the tire will determine the number, size, and shape of the vanes, as well as how far they are mounted from the rotational axis of the tire/wheel combination.

Abstract: An omni-directional air vehicle having a pod with a connected turbofan system, the pod has a body that contains a power source for generating electrical power and a ducted fan with spherical articulation mechanism having a projecting arm with counter-rotating propellers and a ducted shroud around the periphery of the counter rotating propellers and containing drive motors for electrically driving the propellers.

Abstract: A construction intended for a carrier rocket or a satellite, comprising a first construction part (21), which is made of a composite material comprising two essentially parallel walls (23, 24) and a core (25) arranged between these walls, a second construction part (22) and means (26, 31; 26′, 31,39) for joining the first and the second construction parts (21,22). Said means (26, 31; 26′,31, 39) comprising a first fastening element (26) provided with several threads (27), or several first fastening elements (26, 26′) provided with at least one thread (27) each, said first fastening element/elements (26; 26′) being arranged between the walls (23, 24) of the first construction part (21) in such a way that the threads (27) are accessible via the end surface (28) of the first construction part that faces the second construction part (22).

Abstract: It is to provide a superman air motor comprising a disc-type jet turbine engine, the controllable and rotational discharge ports provided at two sides of the discharge chamber for the turbo-jet engine, a fuel tank, and an operation lever connected with the controllable and rotational discharge ports, characterized in that, the rotor shaft of the jet turbine engine is connected with the start-up electrical motor through a clutch; the rotor shaft is connected with a fuel pump through a gearbox; the fuel nozzle of the disc-type jet turbine engine is connected with the fuel tank containing fuel through the fuel pipes via the accelerator control valve and the fuel pump; the operation lever is connected to control the clutch; the handle of the operation lever is provided with an electrical switch, a direction controller and an accelerator controller, the switch is electrically connected with the start-up electrical motor, the accelerator controller is connected to control the accelerator control valve, the directio

Abstract: A method and kit for retrofitting an inertia reel door onto the seat back of a pre-constructed ejection seat is disclosed. The method includes removing existing rivets from the seat back exposing rivet holes. Alignment holes are then drilled into the seat back. An aperture is cut into the seat back along flanges of an upper support bracket and a drogue chute bracket. A doubler is aligned with the rivet holes and alignment holes in the seat back and then attached to the seat back. A track is attached to a wall of the aperture and an inertia reel is mounted to the track. An inertia reel door is attached to the doubler.

Abstract: In a flap operating system, left and right actuators for operating left and right flaps are synchronized with each other by left and right pulleys and first and second synchronizing cables wound in an X-shape around the left and right pulleys. If one of the hydraulic actuators fall into a free failure or fails due to sticking, a difference is generated between the rotational angles of the left and right pulleys. When the difference exceeds a threshold value, the operations of the left and right actuators are stopped, whereby an excessive load is previously prevented from being applied to a main wing structure or the flap operating system.

Abstract: A sparing system for space vehicle constellations. A plurality of space vehicles arranged in at least one mission orbit plane. The number of space vehicles is at least one greater than a minimum number necessary to provide at least a minimum level of service necessary to carry out a constellation mission. If one of the space vehicles fails the remaining space vehicles are repositioned in the mission orbit plane to provide the minimum level of service necessary to carry out a constellation mission.

Abstract: A vertical takeoff and landing aircraft (10) is provided including an aircraft fuselage (12). A plurality of hubs (20) are mechanically coupled to the fuselage (12) and are rotated by at least one engine (22). A plurality of tandem rotor/wings (14) are mechanically coupled to the plurality of hubs (20) and propel and lift the aircraft fuselage (12). A transitional lift wing (16) is mechanically coupled to the fuselage (12) and enables lift on the fuselage (12) during off-loading lift of the plurality of tandem rotor/wings (14). A main controller (24) is coupled to the plurality of tandem rotor/wings (14) and switches the plurality of tandem rotor/wings (14) between a vertical lift mode and a fixed wing mode. A method of performing the same is also provided.

Abstract: A satellite communication system has a first deployment of a plurality of satellites deployed in a medium earth orbit and two later deployments of a plurality of satellites deployed in the medium earth orbit. The first deployment is, spaced so that the second deployment may be easily deployed and interleaved into the first deployment. A ground terminal is used for communicating with the satellites in the first and second deployments.

Abstract: The drogue 11 comprises a canopy 50 supported by a plurality of adjustable ribs 42 and further ribs 43. A control unit 36 is provided for moving the adjustable ribs 42 into a first position P1, in which an air stream can inflate the canopy 50 whereby drag on the canopy causes the drogue 11 to draw a fuel hose 74 from a tanker aircraft 63 into an extended position, and into a second position P2 in which the canopy 50 takes on a cylindrical form and drag thereon in the extended position will be reduced. Selected adjustable supports are movable relative to the others by a control mechanism 41 to adjust a selected portion of the canopy 50 whereby the drag on that portion will be increased and the drogue 11 will move to a new position.

Abstract: An aircraft engine nacelle nose cowl has a supply duct to deliver pressurised hot gas into an internal compartment of the nose cowl. A slot is provided in the nose cowl to enable pressurised hot gas to pass out of the compartment through the slot. As the pressurised hot gas passes out of the compartment through the slot, this causes a film of water on an outer surface of the nose cowl to detach from the nose cowl. The slot is of restricted dimensions which causes localised heating of the nose cowl around the slot as the pressurised hot gas pass out of the compartment through the slot. In this manner ice is prevented from accumulating on the outer surface of the nose cowl and/or ice is removed from the outer surface of the nose cowl.

Abstract: In order to continuously rotate an impeller having an axis parallel to a ground surface in one direction to generate lift, a cover close to a periphery in an opposite lift side is provided within a half of an outer periphery of the impeller, and a cylindrical scroll wheel integrally and concentrically rotating with the impeller is provided in a cavity portion near a root of the impeller, whereby a balance between the lift side and the opposite lift side is broken aerodynamically.

Abstract: A preform is joined to converging surfaces of a structure, such as an airfoil, to form a structural edge. The preform has a body having an acute-angle edge at one end and connecting areas extending from the opposing end for connecting the preform to converging planar elements of a wing or other similar structure. In several embodiments, the acute angle of the preform generally matches the angle relative to converging ends of the planar elements, the preform forming the outer end of smooth, continuous outer surfaces after assembly. The connecting areas may be connected to interior or exterior surfaces of the elements, depending on the orientation of the preform and elements. In another embodiment, the entire preform is placed between the outer ends of the elements for aligning and supporting the elements at the desired location and angle relative to each other.

Abstract: A constant velocity drive mechanism of a rotary-wing aircraft rotor, comprises a torque splitting differential mechanism, comprising a driving disc integral in rotation with a rotor mast and connected to each of two driven discs either side of the driving disc, by a least one connecting pin hinged to each of the discs by one of three ball joint connections. Each of the driven discs is connected to a hub of the rotor by at least one of two driving devices, each of which is also hinged to the hub, so as to drive the hub in rotation about a geometrical axis which can be inclined in all directions about the axis of rotation of the mast.

Abstract: Derivative aircraft and methods for their manufacture. In one embodiment, a derivative aircraft having a derivative wing is derived from a baseline aircraft having a baseline wing. In one aspect of this embodiment, the baseline wing can include an outboard wing portion and an inboard wing portion, the inboard wing portion having a forward inboard wing portion and an aft inboard wing portion. In a further aspect of this embodiment, the derivative wing can include a wing insert having a spanwise wing insert portion and a chordwise wing insert portion, the chordwise wing insert portion of the wing insert being interposed between the forward inboard wing portion and the aft inboard wing portion of the baseline wing, and the spanwise wing insert portion being interposed between the outboard wing portion and the forward and aft inboard wing portions of the baseline wing.

Abstract: According to the invention, in this aircraft, the elements of the inertial reference system are separated according to whether they are intended for navigation (CI) or flight control (5, 6, 7). The accelerometers (5 and 6) intended for flight control are arranged at a vibration antinode, while the gyrometers (7) dedicated to flight control are placed at a vibration node. The accelerometers (5 and 6) and the gyrometers (7) are connected to the flight control computer (12) and their measurements serve as flight control parameters.

Abstract: The present invention is a 2 passenger aircraft capable of vertical and conventional takeoffs and landings, called a jyrodyne. The jyrodyne comprises a central fuselage with biplane-type wings arranged in a negative stagger arrangement, a horizontal ducted fan inlet shroud located at the center of gravity in the top biplane wing, a rotor mounted in the shroud, outrigger wing support landing gear, a forward mounted canard wing and passenger compartment, a multiple vane-type air deflector system for control and stability in VTOL mode, a separate tractor propulsion system for forward flight, and a full-span T-tail. Wingtip extensions on the two main wings extend aft to attach to the T-tail. The powerplants consist of two four cylinder two-stroke reciprocating internal combustion engines.

Abstract: This invention teaches a method for delivering fuel to flying helicopter and fixed winged aircraft that is both safer than and compatible with presently used ‘boom’ and ‘drogue’ airborne fueling systems. This method introduces to the mid-air refueling repertoire the use of refueling drones as additional air vehicles, in a first instance tethered to and deployed from the craft receiving fuel. The recipient drone fuselage, configured with a receptacle for accommodating a tanker-controlled fuel dispensing boom, a forward-facing recipient-controlled fuel capture probe for accommodating fuel dispensing drogues, or both, assures compatibility with all mid-air fuel dispensing equipment in present use. The same invention in a later instance extends the inventory of mid-air fuel dispensing resources to include fueling drones of complementary configuration for deployment from airborne fuel tankers.

Abstract: An aircraft has its wing defined as a wing-like body with a tangential flow rotor in the leading edge. A shroud, under the lower part of the tangential flow rotor, terminates in at least one movable flap defining a lift-generating lip when the rotor is rotating such that the upper part of the rotor, projecting above the level of the upper surface of the wing-like body, is moving rearwardly. Differential adjustment of the flaps in the wings to either side of an aircraft centerline allows directional control and control of banking of the aircraft.

Abstract: An airplane training or amusement device for traveling along a fixed track comprises airplanes forcibly guided along a driving rail supported above the ground on track supports, and driven by the pilot at various speeds. The airplane track is associated with leisure use, but it can also be associated with the use of individual personal transport.

Abstract: A vertical take-off and landing vehicle that employs a thrust assembly, a fuselage, and an intermediate rotation decoupling interface assembly for rotationally decoupling the thrust assembly from the fuselage. The thrust assembly forms a single combined thrust force about the fuselage in order to form a more stable vehicle during flight.

Abstract: An aircraft lifting member (wing) comprises a crossflow rotor 2 formed of a core 4 having rotor vanes 5 mounted around it, disposed in a trough 3 at the front upper part of a wing-like body 1. Rotation of the rotor induces a downwardly and rearwardly directed airflow over the upper surface 6 of the wing-like body 1 generating both lift and thrust. The upper part of the rotor vane path projects above the upper surface 6 and the lift-generating member is open at the leading edge to expose the cross-flow rotor 2 to the incident airflow.

Abstract: An aircraft for vertical take off and landing is comprised of a rotor assembly mounted on a rotating drive shaft extending from the top of a cabin. The rotor assembly is comprised of a truncated-cone top, a spaced apart circular bottom, and internal vanes running radially, between the top and bottom, forming an air impeller. In operation, air is drawn through the central air intake of the top and discharged through an annular nozzle around the circumference of the rotor assembly. As the top rotates, additional air is rammed through scoops mounted at an angle to radii of the top, on the surface of the top. The torque applied to the cabin, due to rotation by the engine of the rotor assembly, is countered by the reaction force generated by a plurality of tabs extending from the cabin sidewall into the airstream flowing downwardly from the nozzle.

Abstract: This invention pertains to a means of aerial lift depending on the use of an air jet blown and channelled (through a nozzle and a vane) exclusively and almost tangentially over a limited segment of a rotating cylinder (a Magnus cylinder) thereby creating a useful depression and lift. The part of the cylinder's surface swept by such jet (which part we will name the "useful segment") is delimited upstream by a nozzle "splitting" a sheet of air almost tangentially over the cylinder and downstream by a vane which will skim the surface of the cylinder and direct the jet away from the surface of the rotating cylinder.

Abstract: The invention relates to an electric rudder rotor which in its simplest construction is in the form of an externally running underwater electric motor and comprises a fixed stator and a rotating rotor, which carries the rotor cylinder, the stator being supplied with electric current and the rotor being rotated by magnetic interaction between the stator and the rotor.

Abstract: The exterior of a vehicle, e.g. the roof of a land vehicle such as a tractor trailer cab, trailer, truck, bus, auto, van, rail car or the like, is provided with exposed moving surface, which moves relatively rearwardly, relatively more quickly than the vehicle progresses. As a result the vehicle may be made to bear more lightly on the ground, so that more weight may be transported. In a preferred embodiment the moving surface is constituted by the exposed upper run of an endless band entrained about fore and aft rollers provided with a driving mechanism e.g. for rotating at least one of the rollers. The lower run of the band may be hidden. Controls are described.

Abstract: A V/STOL aircraft comprising a fuselage, having three sets of wings that are offset lengthwise and vertically. The center set of relatively small relatively thick wings 34 between the canard 14 and the rear relatively thin relatively large aerodynamic lift wings 18 are equipped with identical lift fans 36 enclosed in the wing by upper and lower movable slotted deflectors 40. The attitude of the slatted deflectors may be varied to transition the present invention from hovering to forward flight, and vice versa. The present invention's lift fans are interconnected by a balanced power distribution system, to insure constant, efficient use of total power and provide symmetrical lift about the aircraft's center of gravity resistibility. In the event of an engine failure, the remaining lift is still properly distributed to maintain symmetrical lift, so as to maintain balance and operational control of the aircraft in the lift mode.

Abstract: A lift-producing arrangement suitable for driving a boat by the Magnus effect comprises an elongate tubular envelope mounted for rotation about its longitudinal axis. A drive is provided to rotate the envelope. The envelope is of flexible material, e.g., canvas, to achieve improved performance. Preferably, the envelope is held erect by inflation. The arrangement may be used in addition to a conventional screw-propulsion system for increased fuel economy.