FR3031958A1 - VARIABLE GEOMETRY PROPELLER - Google Patents

Abstract

Variable geometry propeller, whose blades (31, 32) can each rotate between a so-called extended position and a so-called retracted position about an axis of blade rotation (21, 22), this axis being inclined from 0 to 10 degrees relative to the axis of rotation of the propeller. A blade 31 has a so-called inner portion and an outer portion - the only one to be output from the fairing in the so-called retracted position - which do not have the same shape parameters. For an aircraft, it allows to go from one configuration to another, such as a vertical take-off mode like a helicopter to a conventional horizontal flight mode. The main applications concern propeller or jet airplanes, in particular military drones and toys, remote-controlled or self-guided.

Description

Variable Geometry Propeller Field of Application The invention is a variable geometry propeller, able to pass from a first configuration in which it is adapted to a displacement of a first type, for example at low speed to a second configuration. in which it is adapted to a displacement of a second type, for example at a higher speed. It is understood above by configuration of a helix all of its parameters including the diameter, the length of the blades, their shape (in profile plane), the number of blades in operation, and the speed of rotation. One of the objects of the present invention is to provide propellers which are as well adapted to low speed movement when the blades are deployed, as to rapid movement with the blades retracted. For an airplane, this corresponds for example to a vertical take-off when the blades are deployed, and to a high-speed horizontal flight when they are retracted, because a large diameter associated with a small pitch favors traction whereas a small diameter with a high pitch promotes speed. PRIOR ART Many methods are known for varying the characteristics of a helix. Particularly known are CN102001430 (A) Variable-diameter propeller - HAN HU SHENG HUANG / EP2275343 (A1) Variable-propeller pitch - BIANCHI MASSIMILIANO [IT] / US2010040469 (A1) Variable-propeller pitch - BIANCHI MASSIMILIANO [IT] / US2007286728 (Al) Rotatable blade bladed with blades - 25 HOTTO ROBERT [US] / W02008075187 (A2) Variable-pitch propeller - BIANCHI MASSIMILIANO [IT] / US2134660 (A) Adjustable propeller - EVERTS WALTER W / US2504737 (A) Self -proportional pitch changing propeller and control therefor - SHARPES ROY E 30 V US3565544 (A) Marine Propeller - DON MARSHALL J / US4744727 (A) Controllable propeller pitch and watercraft drive - MULLER PETER [CH] / US5252028 (A) Marine propeller assembly with [000] And especially US5562413A Variable Propeller for boats, by TAKO AIHARA & Al, the document which is closest to the present invention. The invention will be better understood, and other objects, advantages and characteristics thereof will appear more clearly on reading the description which follows, which is illustrated by FIGS. 1 to 9, which all represent propellers according to the invention.

Figure 1 shows two identical aircraft each provided with two counter-rotating propellers according to the invention. The aircraft on the left is in vertical takeoff or landing mode, with its two propellers whose blades are in the so-called extended position, while the right one is in horizontal flight mode, with its blades in the so-called retracted position. A single propeller is visible on the right aircraft, because the blades of the rear propeller retract completely into the fuselage in the retracted position. FIGS. 2 and 3 represent the same propeller according to the invention, the blades being in the so-called extended position in FIG. 2 and in the so-called retracted position in FIG. 3. It can be seen that only the outer portions 312, 322 and following of the blades , respectively 31, 32 and following, overflow a cylinder of radius equal to the outer radius of said hub 10.

Figure 4 shows a propeller according to the invention, the blades 31, 32 and following are in said retracted position. We see that these blades are not in a single plane to be superimposed in this configuration. Figures 5 to 9 show different stages of the deployment of the blades, starting from Figure 5 of their so-called retracted position, to arrive at Figure 9 at their so-called deployed position. SUMMARY OF THE INVENTION The invention is a propeller having a variable geometry, comprising a hub (10) rotatable about the axis of rotation of the propeller, comprising at least two axes (21, 22) of blade rotation. located at a distance from the latter, at least two blades (31, 32) each rotatable about an axis of blade rotation (21, 22), between a so-called extended position and a so-called retracted position, characterized in that that in the so-called retracted position, a blade 31 has a so-called internal portion (311) which rotates inside a cylinder of radius equal to the outer radius of said hub (10). According to other features: a blade (31) also comprises a so-called outer portion (312), the profile of which is different from that of the so-called internal portion (311); the profile of the outer portion (312) corresponds to a higher velocity displacement of the helix in the environment than the profile of the inner portion (311); said blade rotation axes (21, 22) are substantially parallel to the axis of rotation of the propeller; Said blades rotation axes (21, 22) are inclined by less than ten degrees with respect to the axis of rotation of the helix; - The pitch of a blade (31) is reversed between said deployed position and said retracted position; fairings fill the spaces between the blades of the propeller in the extension 5 of the outer surface of said hub (10) when the blades are in the so-called retracted position; the invention is an aircraft provided with a variable geometry propeller according to the invention and, in the so-called retracted position, said inner portion (311) of a blade is entirely comprised in a fairing such as the cabin of the aircraft; 10 - the aircraft is provided with a second propeller according to the invention, which rotates in the opposite direction of the first the aircraft is provided with a parachute located in its front part. DETAILED DESCRIPTION OF THE INVENTION The main object of the present invention is to enable the realization of a vertical take-off and landing aircraft, operating as Convair XF 1 Pogo, which was designed in the 1950s. one or more propellers according to the invention can take off vertically as a rocket, and then tilt horizontally for normal flight, then reboot vertically for landing. The computers and sensors available today make it easy to take off and, most importantly, to land, as well as to manage the transition safely, even though they were problems for the Convair XF 1 Pogo. Unlike a helicopter, such an aircraft does not fall where its engines fail. The pilot can hover to where he wants to land. He must then straighten the aircraft until stall, drop a parachute that can be stored in the front of the aircraft to land gently in a vertical position. Shocks can be provided as there were on the Pogo to cushion the shock during such a landing or landing. The invention also makes it possible to make planes that remain horizontal during all phases of flight, and of which only the engines rock from the vertical for the take-off / landing to the horizontal for the normal flight, as the project of Civil transport aircraft Bell / Agusta BA609.

In a simple version, a blade 31 is simply retractable by rotation around its axis of blade rotation 21. In this case it has only the part 311 called the internal part. It is also possible to construct propellers according to the invention, which have blades having only an inner part and others which also have external parts. This makes it possible to vary the number of blades according to the configuration of the helix.

In an improved version, a blade 31 also includes an outer portion 312, and never fully enters the fairing of the hub 10. Advantageously, the profile of said outer portion 312 is in this case different from that of the so-called portion. internal 311.

The profile of the outer portion 312 may for example correspond to a higher velocity displacement of the helix in the environment than the profile of the inner portion 311, as is the case for a vertical take-off aircraft. The axes of rotation of the blades 21, 22 may be substantially parallel to the axis of rotation of the helix, as shown in all the figures, but they may also be inclined, for example by a few degrees, with respect to this axis. . Less than ten degrees of inclination are indeed enough to significantly change the incidence of the blades as a function of their opening. Those skilled in the art can calculate the evolution of the incidence of the blades according to their opening in all cases. Even in the case where the axis of rotation of a blade is parallel to the axis of rotation of the helix, the incidence of the part of the blade in contact with the environment varies as it revolves around its blade axis, which the skilled person can use to adapt the pitch of the propeller to each configuration. In the most common case, the pitch of a blade 31 is lower in said deployed position than in said retracted position, but it is also possible to envisage other solutions. The pitch of a blade 31 may for example be reversed between said deployed position and said retracted position. A propeller 20 according to the invention thus changes direction forwards or backwards without changing the direction of rotation. It is a simple mechanical way to reverse the thrust of a propeller, for example for boats. In a preferred version, fairings fill the spaces between the blades of the propeller in the extension of the outer surface of said hub 10 when the blades are in the so-called retracted position, because it is in this position that the propeller allows the highest speed of the machine it drives, and where an opening to the environment of the rotation mechanisms of the blades could affect the speed. The fairings may for example slide parallel to the axis of rotation of the propeller. In the case where the invention is an aircraft, the inner portion 311 of a blade may be fully included in a fairing such as the cabin of the aircraft. In this case only the outer portion 312 is in operation, and its architecture can be optimized for horizontal flight conditions. To avoid the harmful effects of the propeller torque at the time of vertical takeoff or landing, an aircraft according to the invention is advantageously provided with a second propeller according to the invention, which turns in the opposite direction of the first . The blades of this second propeller may have no external part to retract completely in the fuselage 3031958 5 during the horizontal flight, to avoid in this flight configuration the disadvantages associated with pairs of contra-rotating propellers. One particular design is that one of the propellers is driven by a heat engine while the other, which is used in a vertical position, is driven by an electric motor. The latter being used only for a short time, can thus be lighter, and its regime adapted finely to be able to rotate and stabilize the aircraft in rotation about its longitudinal axis during the take-off and landing phases. The blades can also be retractable entirely, and the aircraft be propelled by a reactor. It thus has a completely smooth configuration in horizontal flight, capable of flying above the speed of sound. It's a way to design vertical take-off and landing fighters, no longer needing a traditional runway or aircraft carrier. The continuously variable transmissions described in PCT / FR-2013-00285 and PCT / FR-2014-00035 by the same author are known. These transmissions are particularly suitable for driving propellers according to the invention, and can also be used to recover the energy of their rotation. The blades can be synchronized with each other by a simple mechanism (not shown), such as those described for the synchronization of the arms in the applications just cited. It is also possible not to synchronize all the blades, to obtain particular configurations in which the blades have different openings.

In an improved version, an elastic return may be installed to recall the blades in their so-called deployed position. When the resistance of the air is too strong to allow rotation of the blades in their deployed position, the effect of resistance is to rotate the blade about its blade axis despite this elastic return. This method can be implemented by those skilled in the art to automatically regulate the position of the blades as a function of the resistance of the ambient medium, air or water, for example, to the rotation of the helix. This method is equally applicable to propellers used to propel a craft, as well as those used to recover energy from a stream of air or water, for example. Main advantages of the invention compared to the prior art A propeller according to the invention allows its user to change a very large number of its parameters, including the diameter, the length of the blades, their shape (in plan in profile ), and even the number of blades in operation, with a simple mechanism and therefore robust, requiring little maintenance. Like a helicopter, an airplane equipped with one or more propellers according to the invention makes it possible to overcome the tracks which are normally necessary for it for take-off and landing, but retains a large part of the advantages of the planes, particularly for what concerns 3031958 6 design simplicity and speed. With respect to the helicopter, an aircraft according to the invention offers significant safety advantages and low purchase and maintenance costs that are related to its design. Applications The invention applies to all types of propellers including traction devices, compression, propulsion, levitation, measurement, and therefore many types of machines such as airplanes, boats, hovercraft, toys, fans, wind turbines, tidal turbines, turbojet blowers. Flying or floating drones are among the most promising applications. 10

Claims (10)

REVENDICATIONS1. Variable geometry propeller, comprising: a hub (10) rotatable about the axis of rotation of the propeller, having at least two blade rotation axes (21, 22) located at a distance from the latter, - at least two blades (31, 32) each rotatable about an axis of blade rotation (21, 22), between a so-called extended position and a so-called retracted position, characterized in that, in the so-called retracted position, a blade 31 comprises a so-called internal portion (311) which rotates inside a cylinder of radius equal to the outer radius of said hub (10). 2. propeller with variable geometry according to claim 1 characterized in that a blade (31) also comprises a so-called outer portion (312), whose profile is different from that of the so-called internal portion (311). 3. variable geometry propeller according to claim 2 characterized in that the profile of the outer portion (312) corresponds to a higher velocity displacement of the helix in the environment than the profile of the inner portion (311). 4. Propeller variable geometry according to claim 1 characterized in that said blade rotation axes (21, 22) are substantially parallel to the axis of rotation of the propeller. 5. Propeller variable geometry according to claim 1 characterized in that said blade rotation axes (21, 22) are inclined by less than ten degrees relative to the axis of rotation of the propeller. 6. Propeller variable geometry according to claim 1 characterized in that the pitch of a blade (31) is reversed between said extended position and said retracted position. 7. Propeller variable geometry according to claim 1 characterized in that fairings fill the spaces between the blades of the propeller in the extension of the outer surface of said hub (10) when the blades are in the so-called retracted position. 8. Aircraft equipped with a variable geometry propeller according to claim 1 characterized in that, in said retracted position, said inner portion (311) of a blade is fully included in a fairing as the cabin of the aircraft . 9. Aircraft according to claim 8 characterized in that it is provided with a second propeller according to claim 1, which rotates in the opposite direction of the first. 10. Aircraft according to claim 8 characterized in that it is provided with a parachute located in its front part.