Ducted fan integrated power plant unit having propeller with central blade wheel

#The present utility model relates to a ducted fan power plant unit of a model airplane, more particularly to a ducted fan integrated power plant unit having a propeller with central blade wheel.

#At present, most ducted fan power plant unit of the model airplane adopts the design of straight duct, i.e. the duct fan and the duct stator outer ring are of straight line design, therefore the diameter or area of the air intake port of the duct fan is equal to that of the air exhaust port of the duct stator outer ring, and when the air drawn in by the duct fan is exhausted rearwards after it passes through duct stator outer ring to the air exhaust port, the acceleration of the air exhaust flow is only proportional to the rotating speed of the engine of the duct fan.

#In addition, in the prior art, due to the fact that the diameter of the spinner and the central shaft is relatively large, the area of the air intake port of the fan is reduced, and that the model airplane is driven only by the blades of the propeller, when high speed flying is needed, the amount of air admission for combustion of the engine is not enough so that air and fuel in engine can not be mixed adequately, resulting in the reduced work efficiency. Furthermore, in the structure of the duct stator having outer ring and inner ring, air stream passes through only the space between the outer ring and the inner ring of the duct stator, the air, after passing through stator guide blades arranged between the outer ring and the inner ring, is exhausted rearwards. In this case, no air flow occurs in stator inner ring. This region where no air passes through, is right next and most close to the central region where engine is located. The result is the disordered air flow will occur in this region and the air flow speed is adversely influenced, which leads to the reduction of propulsive force of the model airplane. At the same time, the surrounding region of the central portion of the engine suffers from poor cooling because no air flows through there, and enough air cannot be supplied for the combustion of the fuel, thereby the engine cannot achieve good working efficiency and due high rotating speed, accordingly, the rated power of engine cannot be fully brought into play or properly used.

#FIG. 1 is a cut-away schematic view of the structure of an embodiment of the present utility model.

#FIG. 2 is a plan view of FIG. 1.

#FIG. 3 is a left view of FIG. 1.

#Referring to FIG. 1 to FIG. 4, the and a ducted fan integrated power plant unit having a propeller with central blade wheel mainly comprises a ducted fan stator 1, a propeller 2, an internal combustion engine 3, a fuel tank 4, a tail cap 5, an air exhaust duct 6 and a cover 7. The ducted fan stator 1 includes an outer ring 11, an inner ring 12, a fixing support 13, in which, the outer ring 11 and the inner ring 12 are connected by several radial connecting bars, these bars have the shape of fan blades which can function as or become stator guide blades 14 and can act as support for supporting the outer ring 11 and the inner ring 12, and the fixing support 13 is provided on the one side of the inner ring and situated parallel to and under the central axis of the ducted fan stator 1. In a preferred embodiment of the present utility model, on the inner surface of the inner ring 12 of the ducted fan stator 1 are provided several radially and uniformly distributed inner ring guide blades 15 with equal length and radiating blade shape to increase the air flow speed entering the duct body of the stator, when the model airplane is in flight. In addition, at the front portion of the outer ring 11 of the duct stator 1, a cone-shaped front portion with the inner diameter being reduced gradually from the outside to the inside is formed to act as air intake guide ring 16.

#A fixing member 17 for fixing the power plant unit is disposed on the outer ring 11 of the ducted fan stator, with which the ducted fan power plant unit having a propeller with central blade wheel and the power plant unit can be easily mounted under the wings of the model airplane or in the mounting slots on the both sides of its inner wall within the body of the model airplane, which slot is engaged with the fixing member 17.

#The propeller 2 has several main blades 21 and a blade retaining ring 22. The retaining ring 22 is of a conic shape and has a central shaft hole, and in the retaining ring 22 several radially and uniformly distributed, central blade wheel like central cone shaped blades 23 are provided. Between each of two adjacent central conical blades 23, a spaced guide opening 24 is formed. Generally, the outer diameter of the end of the main blades 21 is gradually reduced from the front to the rear and has the same inclining angle as the inner periphery of the central air intake guide ring 16 to match the conically reduced tapered air intake ring 16, the inner diameter (root portion) of which is gradually enlarged to match the outer periphery of the retaining ring 22 of the central conical blades 23 which is enlarged from the front to the rear.