RU2015063C1 - Aircraft - Google Patents

Abstract

FIELD: aircraft engineering. SUBSTANCE: aircraft with a beam structure fuselage has a tube-shaped beam fastened to a fuselage nacelle, and coaxial contrarotating pusher propellers. The planes of rotation of the propellers are moved apart along a constructional horizontal at a distance of 0.05- 0.25 of the propeller diameter. The blades are made foldable back relative to the flight direction, and the inner surface of the tail beam is made in the form of a tube and is a matching part of a catapult guide rod. EFFECT: improved efficiency piloting and operational characteristics. 4 cl, 3 dwg

Description

 The invention relates to aircraft, and more particularly to aircraft with propulsion propulsive propulsion type.

 There are various schemes for installing screws, including push type, on an airplane [1].

 As a prototype, an unmanned aerial vehicle (LA) "Scout" was chosen - a free-flying monoplane with a high straight wing and a tail unit mounted on a two-beam structure. The device is equipped with a piston engine, which is located in the rear of the fuselage nacelle and drives a pushing propeller [2].

 This arrangement is favorable for the placement and operation of the optical equipment of the aircraft.

 Scout launch is carried out with a mobile pneumatic catapult, landing - in a vertical network or in an airplane.

 A significant disadvantage of the prototype can be attributed to the impossibility of boosting the characteristics by increasing the diameter of the propeller without drastically rearranging the device (spacing the tail beams, increasing the height of the landing gear), which is limited by the structural-power scheme, balancing and anti-cabbing capabilities of this aircraft.

 The aim of the invention is the possibility of using for aircraft the indicated type of large-diameter propeller.

 This goal is achieved by the fact that in the proposed aircraft, the tail beam is made in the form of a pipe, which is attached to the fuselage nacelle by means of a power rod equipped with coaxial counter-rotation propellers. In this case, the rotation planes of the propellers are spaced along the construction horizontal of the fuselage by 0.05-0.25 of the diameter of the propeller, and the propeller blades can be made folding backward relative to the direction of flight, the folding hinge being placed in the root of each blade, the folding angle of the first propeller blades is greater the angle of folding of the blades of the second screw, and the length of the tail boom is greater than the length of the blades of the propellers. In addition, the inner surface of the tail boom can be made in the form of a cylindrical orienting tube, which is a mating part of the guide rod of the catapult.

 In FIG. 1 shows the structural layout of the aircraft according to the proposed technical solution, revealing the relationship and relative position of the elements of the device; in FIG. 2 - one of the possible options for constructive fixing of propellers on the power rod; in FIG. 3 - photo of an unmanned aircraft according to the proposed scheme.

 The nacelle of the fuselage 1, wing 2, tail 3 on the tail boom 4, chassis 5 (in Fig. 1 shows a ski-type chassis) assembled according to the normal aerodynamic design. In this case, the tail boom 4 is attached to the nacelle of the fuselage 1 by means of a power rod 9, on which the nose 6 and tail 7 propellers are mounted. The distance between the planes of rotation of the bow 6 and tail 7 screws is 0.05-0.25 of their diameter (screws of equal diameter). The minimum distance between the planes of rotation of the propellers is selected from the condition of eliminating overlap of the blades in the blowing mode with the greatest amplitude of oscillation of the end parts of the blades (technological parameter), and the maximum distance from the condition of ensuring a difference in torque on the nose and tail rotors of less than 20% (Vozhdaev V . S. Method and results of parametric studies of the aerodynamic characteristics of a coaxial screw system in hovering and vertical lifting modes. M: Transactions of TsAGI, issue 1953, 1978, pp. 48-50) . The folding angle of the nose screw 6 (the angle between the longitudinal axis of the blade 8 and the building horizontal of the fuselage) is α, the tail rotor 7 is β, with α> β.

 Shown in FIG. 2, the structural fastening of screws 6 and 7 on the power rod 9 involves the transmission of torque from the engine 12 through a gearbox 13 (a gearbox variant based on spur gears and light series bearings is shown) to coaxial hubs 15 and 16. In this case, a spring can be placed inside the hub a blade folding mechanism 14.

 Photo (Fig. 3) of an unmanned aircraft according to the proposed technical solution allows you to more clearly imagine the relative position of the main elements of its structure.

 The operation of the device is as follows. At the launch of the aircraft, for example, from the catapult onto the guide rod of the latter, the aircraft is pushed by the tail beam mate 11. Due to the axial asymmetry of the tip of the tail beam 4, which engages with the accelerating shoe (yoke) of the catapult, the aircraft is fixed in roll; the required course and pitch are achieved by the corresponding orientation of the catapult guide rod at the time of acceleration.

 The mid-flight flight of the aircraft is carried out in the traditional way for propeller-driven aircraft.

 The landing of the apparatus is carried out in the network or in a glider on the chassis 5, while the engine is switched off (separation of the engine shaft and propellers), the blades 8 of the nose 6 and tail 7 of the screws are folded, respectively, to the angles α and β by means of the incoming air flow (spring mechanism 14 folding blades). The folding of each blade 8 is relative to the hinge 10 located in its root part in order to minimize the loss of efficiency of the screw.

The proposed technical solution in comparison with traditional aircraft of the aircraft circuit with pushing propellers allows to obtain the following advantages;
with the diameter of the propellers equal to the prototype, increase propulsion thrust, including by eliminating circumferential losses;
to simplify the balancing and piloting of the aircraft, since the twin propellers provide symmetry of airflow around the aircraft structural elements behind the screws (there is no reactive moment), and the total gyroscopic moment is zero (the right and left maneuvers of the aircraft are the same);
in principle, restrictions on the diameter of propellers are removed, which allows the use of extra-large diameter screws for a number of special tasks (for example, for high-altitude or low-power aircraft).

Claims (4)

 1. Aircraft comprising a beam structure fuselage, a nacelle, beams, a wing, a tail, an engine with a propelling propeller, characterized in that the fuselage tail beam is made in the form of a pipe fixed to the fuselage nacelle by means of a power rod equipped with coaxial counter-rotation screws.  2. The aircraft according to claim 1, characterized in that the plane of rotation of the propellers are spaced along the construction horizontal of the fuselage at a distance of 0.05 - 0.25 of the diameter of the propeller.  3. The aircraft according to claim 1, characterized in that the propeller blades are made folding backward relative to the direction of flight, the folding hinge is located in the root of each blade, the folding angle of the nose propeller blades is greater than the folding angle of the tail propeller, and the tail boom is longer than the length propeller blades.  4. The aircraft according to claim 1, characterized in that the inner surface of the tail boom is made in the form of a pipe, which is a mate of the guide rod of the catapult.

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