WO2013077718A1 - Retractable rotor blades for rotary-wing aircraft - Google Patents

Abstract

The invention relates to retractable rotor blades for rotary-wing aircraft, with a mechanism which makes it possible to reduce the span of the rotor blades when the aircraft is not operational and to increase same in order to generate lift. The invention aims to provide a type of rotor blades that is completely different from the blades currently available on the market, making it possible both to take up less space when parking the aircraft and to transport the vehicle easily overland outside of airfields without having to dismantle the rotor blades.

Description

 RETRACTABLE ROTOR BLADES FOR WING AIRCRAFT

 ROTATING

DESCRIPTION

OBJECT OF THE INVENTION

The object of this invention is to provide a type of rotor blades for rotating-wing aircraft that are totally different from those currently on the market, with a retractable mechanism that allows to shorten the wingspan of the rotor blades when it is not in operation and lengthen this one to perform its normal lift function. On the one hand this mechanism allows the aircraft to occupy less space when parked and on the other it facilitates, if necessary, the transfer of the vehicle by land outside the airfields without having to disassemble the rotor blades.

BACKGROUND

In the field of aeronautics, rotating-wing aircraft use fixed-blade blades invariably in their rotor whether they are in use or not. This could cause, among other things, two main problems: the first a space problem when parking the aircraft and the second a practical problem when having to disassemble and subsequently reassemble the rotor blades, to be able to transfer these out of the aerodromes to the ground. artifacts

Taking all this into account, the development of retractable rotor blades for rotating-wing aircraft was considered so that when the rotor is not in use, the blades can be folded down thus reducing their size and when required, they can be deployed until they reach their maximum size necessary to perform their lift function. Currently there are a type of shovels that considering this problem fold over themselves. However, this type of mechanism requires the pilot, co-pilot or technical staff to manually undo the rotor blades in order to perform the lift function. We can see this model of rotor blades in US Pat 7,857,590.

The main advantage of the invention presented here over the aforementioned is that the deployment of the blades as well as the folding thereof is performed automatically with the increase or decrease of the rotational speed of the rotor.

Another advantage of this system is that the initial force necessary to rotate the rotor with the folded blades is less than the initial force necessary to rotate a conventional rotor with fixed blades, which translates into less engine and the transmission in the case of helicopters.

BRIEF DESCRIPTION OF THE FIGURES

To complete the description that is being made and in order to help a better understanding of the characteristics of the invention, the present description is attached, as an integral part thereof, to the drawings in which for illustrative and non-limiting purposes, represented the following: Figure 1.- Shows a top view of the rotor (1) with the blades (2) folded up as they would be at rest (position 0), being able to appreciate the little space they occupy in this position. Figure 2.- It shows a top view of the rotor (1) with the blades (2) deployed as they would be in operation (position 1) being able to appreciate their total wingspan.

Figure 3.- Shows a side view of the section A of the blades (2) shown in Figure 2 where the alar profile is seen.

Figure 4.- Shows a top view showing the section B of Figure 3 where you can see the inside of the blades (2) as well as the mechanism (3) consisting of a pulley (4) with a spring (5 ) and a cable (6) that allows to deploy or retract the blade sections.

Figure 5.- Shows a top view of the rotor (1) with the blade (2) deployed (position 1) showing the section B of Figure 3 where the inside of the blade can be seen as well as the mechanism (3).

Figure 6.- It shows a top view of the rotor (1) and the retracted blades (2) where the jet engines (7) can be seen at the distal end for the gyrocopter mode. Figure 7.- Shows a top view of the rotor (1) and the deployed blades (2) as they would be in operation, where the total size of the same can be seen, and where the jet engines (7) are observed at the tips of these (distal end) for the gyrocopter mode. Figure 8 shows a top view showing the section B of Figure 3 where the inside of the blades (2) as well as the mechanism (3) can be seen in the linear spring mode.

As mentioned earlier, the great advantage of this type of blades is its ability to automatically reduce or increase its size depending on whether or not the rotor is in operation.

DETAILED DESCRIPTION OF THE INVENTION With reference to the previous figures the blades (2) of the rotor (1) are divided into at least two segments that retain the same shape (alar profile) but each of smaller size than its previous consecutive. The root or proximal end, is the largest segment that is attached to the rotor (1) and that houses inside the mechanism (3) that allows to deploy and fold the blade (2) as well as the other segments of it When it is at rest.

This mechanism consists of a cable (6) with one end attached to the distal end of the blade (2), which in turn is the smallest segment, and the other end wound to a pulley (4) limited in its movement by a spring (5). While the rotor (1) is at rest, this spring (5) is the one that holds through from the cable to all the segments of the blade folded into the larger segment (position 0).

When the rotor begins to rotate, the centrifugal force acting on the blades gradually overcomes the force of the spring which yields allowing the blade segments to be deployed until they reach the maximum wingspan necessary for the aircraft's lift (position 1). When the rotor loses speed, the centrifugal force acting on the blades decreases and the spring rotates the pulley by winding the cable and in turn folding the blade segments into each other until it reaches the initial position 0 again.

In another embodiment of the invention, the mechanism that allows to deploy and fold the blade segments could be constituted by a linear spring (8) which is located on one side attached to the proximal end (the root) and on the other attached to the distal end of the blade. Inside each of the segments there is a guide that keeps the spring centered at all times.

In addition to the helicopter where the engine force acts directly on the main rotor by rotating it to achieve lift, there is another type of rotating-wing aircraft called a gyrocopter.

The gyrocopter is a rotating wing aircraft that flies like airplanes but its wing is a rotor that rotates by the action of the relative wind that crosses it from the bottom up. That is why we can consider it a hybrid between the airplane and the helicopter: like the airplane, its propulsion is carried out by means of a propeller, but instead of wings, it has a rotor like the helicopter. This rotor does not It is connected to the aircraft engine, but it rotates freely driven by the air that passes through it, thus generating the lift force. In case of an engine stop in flight, the autogyro plans and begins to descend slowly; The faster it does, the faster the rotor blades rotate, storing energy and providing more lift. The autogyro can achieve very slow flight speeds, although it does not have the possibility of stopping in the air.

In the case of gyrocopters, to help extend the retractable rotor blades from the zero resting position to the lift position 1, it was thought to place two jet-type propulsion engines (7) at each end of the blades controlled by a switch When these engines are started, the rotor begins to rotate and the centrifugal force acting on the blades overcomes the force of the spring that holds the blades folded and they extend until they reach position 1 ready to perform their lift function.

Once the maximum wingspan is reached, the turbine-type engines are turned off and the rotor continues to rotate only by the action of the relative air that crosses it from the bottom up as normally happens in the case of the gyrocopter with fixed wings. These engines (7) will be driven only to take off and optionally for landing, remaining off during the flight.

This mechanism of jet-type engines offers additional advantages such as shortening the take-off run providing even the ability to perform vertical takeoffs. On landing, the operation of these engines allows to control the rotational speed of the rotor and in turn the lift of the aircraft, opening the possibility to make vertical landings such as helicopters. Another embodiment for rotating the gyrocopter rotor with the retractable blades from zero rest position to lift position 1, is to add a pre-rotor, an electrical or mechanical mechanism directly connected to the rotor, which helps break the inertia of rest and rotate it by having the centrifugal force act on the blades unfolding its segments until reaching the maximum wingspan.

Claims

CLAIMS Having described my invention sufficiently, I consider as a novelty and therefore claim as my exclusive property, the content of the following clauses: 1. Retractable rotor blades formed by at least two segments that allow to shorten the wingspan of the blade when the rotor is not in operation and lengthen it to fulfill its lift function, characterized by the inside of which have a mechanism consisting of a pulley limited in its movement by a spring inside the proximal end of the blade, around which is a cable whose opposite end is attached to the distal end of the blade and that keeps the segments folded inside each other when the rotor it is at rest, when the rotor rotates, the centrifugal force overcomes the force of the spring which yields allowing to deploy the segments reaching their maximum wingspan and when the rotor decreases its rotational speed, it retracts the segments of the blade one inside the other thus shortening its wingspan 2. Retractable rotor blades according to claim # 1 characterized in that the mechanism inside the blades may also be a linear spring attached on one side to the proximal end of the blade on the other to the distal end. 3. Retractable rotor blades according to claim # 1 characterized in that additionally this system may have some Jet-type engines at the distal end of the blades of the gyrocopters, whose function is to rotate the rotor from a rest position, thus helping to deploy the blades, being operated only to take off and optionally at landing, remaining off during the flight. 4. Retractable rotor blades according to claim # 1 characterized in that this system may have a pre-rotor, which is an electrical or mechanical mechanism connected directly to the gyrocopter rotor, to initially rotate it from a rest position. , getting the centrifugal force applied to the blades to deploy their segments until they reach their maximum wingspan and the rotational speed necessary for the lift, and once this is achieved, the pre-rotor is disconnected from the rotor allowing it to rotate freely.