Abstract: A propeller balancing method and apparatus provides relocation of the propeller's center mounting hole to the propeller's center of mass. The method uses a conventional balance stand, by first attaching a balanced drill guide fixture to the hub of the propeller in such a way that the drill guide fixture can be moved slightly relative to the propeller hub to achieve balance and define a new center for the propeller. Once balance is achieved, the fixture and propeller assembly is removed from the balance stand. Then, a new oversize hole can be drilled in the propeller hub through the drill guide, and an appropriate (concentric) bushing installed.

Abstract: An aircraft has at least one drive motor coupled to first and second propellers for forward thrust of the aircraft. The first propeller is dimensioned for takeoff and landing conditions and for flight conditions below a predetermined first flight altitude. The second propeller has a radius which is larger than a radius of the first propeller and is dimensioned for a second flight altitude which is substantially greater than the first flight altitude. The two propellers are alternatingly coupled with the at least one drive motor so that the two propellers are respectively individually adapted to the power of the at least one drive motor for a full utilization of the power of the at least one drive motor for forward thrust.

Abstract: Indexing a propeller blade so it leads intake valve timing by a specific amount causes an increase in engine power. The proper indexing allows the high energy propeller wake in the form of an acoustic wave to be ingested by the induction system and arrive at the intake valve just as the valve is opening. When the Wave arrives just as the valve is opening, the wave causes a momentary increase in manifold pressure which adds pumping potential to force additional airflow into the engine cylinders which results in a power increase. This technique called propeller syncro-phasing causes the propeller blade to behave as a "zero stage supercharger". Adding a trailing edge extension to the propeller blade chord at the radius corresponding to the induction inlet causes a local increase in slipstream total energy adding additional energy to the induction airflow resulting in additional engine power.

Abstract: The invention is a shroud for a reversible thrust fan, the shroud having a inlet duct and an exhaust nozzle with the fan located there between. In general terms, the shroud includes a system for increasing the efficiency of the exhaust nozzle when acting as an inlet duct when the fan is providing reverse thrust. The system comprising a plurality of auxiliary inlet duct systems spaced about the circumference of the exhaust nozzle in proximity to the rear end thereof, the auxiliary inlet duct systems extending from the exterior surface of the exhaust nozzle to the interior surface thereof. The auxiliary inlet duct systems are movable from a closed position to an open position wherein air can be drawn from the exterior surface of the exhaust nozzle to the interior thereof when the fan is providing reversed thrust.

Abstract: A low-aspect ratio propeller system is provided with a multiple ring structure formed with a plurality of circular or non-circular, annular, narrow equivalent air foil rings which are held by rails in a predetermined relationship with the propeller blades. The upstream ring is located downstream from the tip vortex of the propeller within the axial span of the propeller. One or more additional downstream-located rings are used so as to provide at least one annular multiple ring-defined pump aperture through which peripheral vortices generated by the propeller blades or fan blades may enhance the mass flow. In one propeller system, a low-aspect-ratio propeller is employed with high blade angles of attack and non-stall capability to generate strong vortices which enhance the beneficial effect of the multiple ring structure. These vortices increase thrust because their induction action on the rings increase beneficial ring flow circulation.

Abstract: An aircraft engine is mounted on an aircraft wing such that the wing wake sheds along a zone at a predetermined position on the engine disk thereby minimizing dynamic loads or resonance. For a prechosen or design set of engine conditions the strength of the dynamic load is a function of the radial location of the zone on the disk having at least one relative minima between the centerline and the perimeter of the disk. The zone is positioned on the disk such that the value of the function is essentially a relative minima.

Abstract: A pusher turboprop engine is provided with an interior exhaust duct structure which directs the hot turbine gases through and out of the engine nacelle and around the rear spinner which surrounds the propeller hub. The spinner supports blade-shaped shields which protect the roots of the propeller blades from the hot exhaust gasses.

Abstract: A pusher turboprop engine is provided with an interior exhaust duct structure which directs the hot turbine gasses through and out of the engine nacelle to an annular duct mounted on the rear spinner which surrounds the propeller hub. The rotating annular duct includes blade-shaped shields which protect the roots of the propeller blades from the hot exhaust gasses and also pulls warmed cooling air through the engine nacelle thereby providing a rearwardly directed jet thrust to augment the propeller thrust.

Abstract: An internal combustion engine is installed near to the center of gravity of an aircraft and has a power output shaft which is arranged to be inclined with respect to the aircraft longitudinal axis, in the direction of a high empennage of the aircraft. An extension shaft follows coaxially from the engine power output shaft, which extension shaft is connected to a propeller shaft by a single reorientation transmission or gear box. The gear box is designed as a miter gear box. A pusher propeller is arranged at the rear end of the empennage. Instead of a miter gear box, a constant speed universal joint can also be utilized.

Abstract: In combination with a propeller disposed in an aircraft, aft from the nose portion of the craft, an improvement is provided for reducing noise, as well as mechanical load on the propeller blade, and includes a construction part situated upstream from the propeller and being exposed to the oncoming air flow prior to reaching the propeller, thus being an obstacle that has a particular contour in a plane transversely to an axis of rotation of the propeller, so that at least the rear edge, as seen in peripheral direction of rotation of the propeller, forms an angle that is not zero in relation to a leading edge of the propeller, when the propeller as a whole is in a horizontal disposition.

Abstract: Double propeller for propelling aircraft, with two coaxially and axially offset propellers that can be driven separately by associated drive mechanisms through a central shaft and a hollow shaft. To reduce noise and maintain safe operation even when one propeller drive breaks down, the propellers rotate in the same direction and can at at least one prescribed angle of rotation to each other be coupled together in such a way that they cannot rotate in relation to each other by means of a clutch that can be disengaged.

Abstract: An aircraft is disclosed as having the components of a high wing airframe, a single engine of the 360 type, and a propeller formed with airfoil cross sections along the blades thereof having profiles which, when particularly matched with the designated engine and type of aircraft, result in superior performance than is available when any of the components is matched with other components. Specific disclosures of the front and rear cambers of the blades provide aerodynamic characteristics which optimize the performance capabilities of the high wing airframe in conjunction with the designated engine.

Abstract: An assembly for mounting a propeller, which is driven by an aircraft engine, on a longitudinal member of a lightweight aircraft. The assembly includes a sleeve positioned about the longitudinal member, and a pair of opposed adjustable cups securing the sleeve at its ends longitudinally relative to the longitudinal member. A rotating mechanism mounted to the propeller, rotatable about the sleeve, and driven by the aircraft engine rotates the propeller concentrically about a longitudinal axis of the longitudinal member. Suitable bearings are disposed between the rotating mechanism and the sleeve and the rotating mechanism rotates on these bearings. Vibration dampening rings are placed between the cups and the sleeve and dampen the vibration transmitted between the rotating mechanism and the longitudinal member.

Abstract: An aircraft has a pair of wing portions with propellers of a propeller pair which are driven and synchronized by a fluid transmission between the power plant and the propellers. A fluid line structure keeps most components of the craft together and consists preferredly of three pipes which are also utilized to carry the driving fluid to and from the motors, to hold the motors and to hold the wings. The take over of a plurality of functions by the interior pipe structure reduces weight and secures safe and economic operation of the craft. The aircraft is provided with a propeller and motor arrangement that is retractable into a slot formed in the front portion of the wings.

Abstract: In an aircraft arrangement comprising an aircraft fuselage provided with a wing on either side thereof and provided with a propeller propulsion system at the rear of the fuselage, the improvement comprising a propulsion system comprised of at least two independent propulsion units each mounted in its individual lateral fuselage section in a rear fuselage part formed by the central fuselage section originating from the outer contour of the main fuselage section and tapering toward the fuselage end, the lateral fuselage sections having an outer contour tapering in spindle form toward the fuselage rear to the diameter of the propeller spinner of each propulsion unit and propellers on each propulsion unit arranged behind the fuselage and the air frame.

Abstract: This invention relates to an improvement in an aircraft having a tail-mounted, shrouded pusher-type propeller and an engine mounted in front of the shroud, the improvement comprising exhaust pipe running from the engine to the shroud.