Single Blade Propellers
Faster, lighter, & smoother, with
higher efficiency, reduced bending & gyroscopic stress...
A single-blade propeller may be used on aircraft to generate
thrust. Normally propellers are multiblades but the simplicity of
a single-blade propeller fits well on motorized gliders, because
it permits the design of a smaller aperture of the glider fuselage
for retraction of the power plant. The counterbalanced teetering
mono-blade propeller generates fewer vibrations than conventional
multiblade configurations. Everel Propeller
Corporation in the 1940s produced the counterbalance single-blade
Walter Everel [ Everts ] // Everel
Principles of the One-Blade
[ PDF ]
Propeller propulsion unit for aircrafts in general
Beretta, et al.
A propeller propulsion unit for aircrafts in general including a
rotation shaft driven by a motor, the unit including a
single-blade propeller and a counterweight that are connected to
the shaft, the counterweight being arranged in a substantially
diametrical position with respect to the single blade in order to
balance the moment generated by centrifugal force and being
variably offset with respect to the axis of the blade in order to
balance the moment generated by the traction force of the
BACKGROUND OF THE INVENTION
The present invention relates to a propeller propulsion unit for
aircrafts in general.
Aircrafts in general that do not use jet propulsion systems are
conventionally provided with one or more propellers that convert
the power supplied by the motor into traction.
The propellers normally used are of various kinds, such as for
example pusher or pulling propellers, with fixed or variable
pitch, and ducted; these propellers are furthermore constituted by
two or more blades that are arranged so as to balance, on the
propeller axis, both the action of the centrifugal force, produced
by the rotation of said propeller, and the moments caused by the
aerodynamic forces generated by the relative speed of the blade
with respect to the air.
Propellers having a single blade are used exclusively in the field
of flying model aircrafts, i.e., with power plants having
extremely small power ratings.
The use of a single-blade propeller would certainly be useful in
many applications in aircrafts, since it would be possible to
improve the efficiency of the propeller and have considerable
constructive simplicity; however, this type of use has so far been
unfeasible, since all the problems that arise from compensating
the radially-directed forces, inertial forces, and aerodynamic
forces, with their corresponding moments, generated by the
relative speed of the blade with respect to the air, have not been
solved. These factors, which also vary as the relative speed of
the blade with respect to the air varies, would produce
troublesome stresses and vibrations that might lead to fatigue
failure, especially if considerable masses are involved.
Accordingly, the use of a propulsion unit with single-blade
propeller has never had a practical follow-up.
SUMMARY OF THE INVENTION
A principal aim of the invention is to solve the above problem by
providing a propeller propulsion unit for aircrafts in general
that allows to use a single-blade propeller without having
imbalances of the forces involved that might produce vibrations or
Within the scope of this aim, a particular object of the invention
is to provide a propulsion unit in which it is possible to
automatically compensate for any imbalances in forces, working at
all times with a system that is balanced and as such is never in
abnormal operating conditions.
Another object of the present invention is to provide a propeller
propulsion unit for aircrafts in general that is capable of giving
the greatest assurances of reliability and safety in use thanks to
its particular constructive characteristics.
Another object of the present invention is to provide a propeller
propulsion unit for aircrafts in general that can be easily
obtained starting from commonly commercially available elements
and materials and is furthermore competitive from a merely
economical point of view.
This aim, these objects, and others that will become apparent
hereinafter are achieved by a propeller propulsion unit for
aircrafts in general, according to the invention, comprising a
rotation shaft driven by a motor, characterized in that it
comprises a single blade that is connected to said shaft and a
counterweight that is arranged in a diametrical position with
respect to said blade in order to balance the moment generated by
centrifugal force and is offset with respect to the axis of said
blade in order to balance the moment generated by the traction
force of the single-blade propeller.
BRIEF DESCRIPTION OF THE DRAWINGS
Further characteristics and advantages of the invention will
become apparent from the following detailed description of some
preferred but not exclusive embodiments of a propeller propulsion
unit for aircrafts in general, illustrated only by way of
non-limitative example in the accompanying drawings, wherein:
FIG. 1 is a schematic view of a propulsion unit with a
single-blade propeller and an offset counterweight;
FIG. 2 is a view of a propulsion unit in which the blade,
the hub, and the counterweight can oscillate with respect to the
FIG. 3 is a schematic view of a propulsion unit in which
the blade is pivoted with respect to the hub;
FIG. 4 is a schematic view of a propulsion unit in which
the hub is pivoted with respect to the shaft and the
counterweight is fixed on the shaft;
FIG. 5 is a schematic view of a propulsion unit in which
the blade is rotatable about an axis that is substantially
parallel to its own axis;
FIG. 6 is a view of a propulsion unit in which the blade is
rotatable about its own axis;
FIG. 7 is a schematic view of the propulsion unit according
to the invention, applied to a powered glider;
FIGS. 8 and 9 are schematic views of the offset of the
counterweight with respect to the axis of the blade;
FIGS. 10 and 11 are schematic views of the possibility of
varying the axial offset, in which the oscillations have been
exaggerated to clarify the concept.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the above figures, the propeller propulsion
unit for aircrafts in general, according to the invention,
comprises a rotation shaft 1 driven by a motor that is not shown
in the drawings.
The single blade 2 and a counterweight 3 are connected to the
In order to solve the problem of the imbalance caused by the
moment generated by the traction force, the center of gravity of
the counterweight is axially offset with respect to the
center-of-gravity axis of the blade, so as to generate a new
moment, produced indeed by the centrifugal forces, that is capable
of balancing the previous moment.
In order to better clarify the concept, reference should be made
to the diagrams of FIGS. 8 and 9, in which Fcp designates the
centrifugal force on the blade, Fcc designates the centrifugal
force on the counterweight, Ft designates the traction force, and
Fr designates the resisting force of the blade.
As shown by the accompanying drawings, in order to compensate for
the moment produced by the traction force Ft it is necessary to
create a moment that balances it, and this is achieved by axially
offsetting the counterweight 3, as shown in FIG. 8, along the axis
of the shaft 1, whereas in order to compensate for the resisting
force of the blade, as shown in FIG. 9, an axial offset is
produced through an angular displacement of the counterweight 3 on
the plane that it traces by rotating; in this manner, the
counterweight is displaced, albeit slightly, from a position that
is exactly diametrical with respect to the blade.
With reference to the drawings, FIG. 1 illustrates a solution with
a counterweight 3 having a fixed axial offset, said solution being
shown conceptually in the diagrams 8 and 9.
This solution allows to solve the problem of the imbalance of the
forces involved in constant flying conditions.
However, even if operation occurs at a constant rotation rate,
flying conditions are variable, and in particular the traction
coefficient, and therefore the value of said traction force, can
This variability produces an imbalance, since the balancing moment
generated by the axial offset is fixed and therefore does not take
into account the change in the traction force.
In order to solve this problem, the proposed solution provides for
a change in the axial offset, so as to balance the single-blade
As shown schematically in the diagrams of FIGS. 10 and 11, wherein
d designates the axial offset, one result of the present invention
is pointed out, namely the utilization, as the traction force Ft
varies, of a change in the axial offset d, which is achieved by
allowing the single-blade propeller to oscillate with respect to
the shaft by means of a pivot that allows to form an angle
.varies., even a small one. As shown schematically in FIG. 11, it
is thus evident that as the traction force Ft varies, the axial
offset d also varies and the resulting moment of equilibrium is
In practice, therefore, a device is provided which interconnects
the blade, the shaft, the hub, and the counterweight and is
capable of creating, by utilizing centrifugal forces, another
opposite moment that can vary as the traction coefficient varies.
In order to achieve and control the movement produced by the
centrifugal forces, the distance, measured along the rotation
axis, between the center of gravity of the blade and the center of
gravity of the counterweight has therefore been changed, producing
a change in the distance that is a function of the imbalance, in
order to achieve the intended substantial balance.
As shown in FIG. 2, the distance is changed by means of a pivot 10
that allows the hub 4, the blade 2, and the counterweight 3, which
are rigidly provided on the hub, to rotate about an axis that is
perpendicular to the shaft 1.
From a conceptual design point of view, the involved centrifugal
forces, which are extremely large, are discharged onto the hub 4,
whereas the more modest torque transmitted from the shaft to the
propeller is discharged onto the pivot 10.
A solution is thus proposed that is capable of meeting the
requirements of adapting the axial offset without having excessive
In the embodiment of FIG. 3, the hub 4 and the counterweight 3 are
rigidly coupled to the shaft 1, whilst the blade 2 is pivoted to
the hub 4, thus obtaining a conceptual diagram that is similar to
the preceding one.
From a conceptual design point of view, the pivot 10 of the blade
is subjected both to almost all the torque transmitted by the
shaft to the propeller and, most of all, to the centrifugal force
to which the blade is subjected.
The above-described solution therefore entails greater structural
and construction problems, but it has the advantage that it is
optionally possible to fold the blade 2 backward when it is not
being used, so as to avoid creating resistance to motion.
An intermediate solution, which is conceptually linked to the
preceding ones, is shown in FIG. 4; in this solution, the
counterweight 3 is arranged on the shaft 1 and the hub 4 is
rigidly coupled to the blade and pivoted with respect to the shaft
According to a different embodiment, the axial offset can be
achieved, as shown in FIGS. 5 and 6, by displacing the single
blade 2 about an axis that is substantially parallel to the axis
of the blade 2 and is substantially perpendicular to the shaft 1.
This variation in the axial offset value can be achieved, as shown
in FIG. 5, by rotating the blade 2 about a secondary shaft 15 that
is parallel to the axis of the blade 2, and therefore it is
possible to vary both the axial offset and the pitch of the blade
2 and therefore the traction of the propulsion system is changed
without altering the rotation rate of the motor, thus achieving a
simultaneous adaptation of the pitch of the blade 2 and a change
in the extent of the axial offset between the axis of the center
of gravity of the blade 2 and the center of gravity of the
This solution provides considerable advantages, such as a flying
condition that theoretically always provides for the maximum
efficiency of the propeller, and entails constructive difficulties
that are considerable with respect to those described previously.
Another embodiment, shown in FIG. 6, changes the pitch of the
blade 2 and therefore Fp instead of resorting to an axial offset.
In this case, therefore, the opposite moments are canceled out
whilst keeping the value of traction constant at all times.
The blade 2 in practice is rotated about its own axis, providing a
solution that is certainly simple but has the limitation of
providing a traction value that is theoretically always constant.
From the above description it is thus evident that the invention
achieves the intended aim and objects, and in particular the fact
is stressed that a single-blade propulsion unit is provided which
allows to compensate for the resulting imbalances in a very simple
way, thus making this type of propulsion unit particularly adapted
for application to powered gliders, in which it is necessary to
retract the propulsion unit once the soaring altitude has been
With conventional solutions, either a fixed two-blade propeller is
used, with the need to provide a recess that is twice the one of
the single-blade propeller, or foldable two-blade propellers are
used, which are structurally complicated and not very effective.
The invention thus conceived is susceptible of numerous
modifications and variations, all of which are within the scope of
the inventive concept. All the details may furthermore be replaced
with other technically equivalent elements.
In practice, the materials employed, so long as they are
compatible with the specific use, as well as the contingent shapes
and dimensions, may be any according to the requirements.
Helicopter single-blade rotor
The present invention relates to a single-blade main rotor for
helicopters designed so that the component of the blade lift
normal to the rotational axis of the rotor is compensated by the
inertial force obtained through the self-adjustment of the
position of the rotor centre of mass relative to its rotation
axis, it being provided that the position of the rotor centre of
mass is determined by the coning angle of the blade.
particular, the EPO does not guarantee that they are complete,
up-to-date or fit for specific purposes.
 The present patent application for industrial invention
relates to a single-blade rotor designed to be used as main rotor
in helicopters and other types of rotorcraft. The rotor supports
the helicopter during hovering and translated flight and, by means
of its controls, allows execution of the manoeuvres typical of
this type of vehicle.
 To this end, helicopters are usually equipped with vertical
axis rotors provided with two or more identical blades joined by
hinges or similar means to a central propeller hub, which is in
turn fixed to the upper end of a vertical mast driven by a system
for the transmission of the rotary motion connected to one or more
 When maintained in rotation at the appropriate speed, the
blades support the helicopter because of the upward lift produced
as a consequence of the relative air speed with respect to the
aerodynamically profiled blades. Moreover, the blades are subject
to the weight force and, due to rotation, to the centrifugal
force. The balance of all these forces and their moments with
respect to the joints of the blades to the rotor hub and the mast,
to which the weight of the rotorcraft is applied, determines the
geometrical position of the blades, which, with respect to the
plane orthogonal to the rotation axis, are directed upwards with a
normally small coning angle. The entity of the total lift is
adjusted by the pilot through the collective control lever that
acts on the blade pitch by means of rods, levers, and rotating
mechanisms connected with suitable pitch horns located on the hub
of each blade, coupled in a rotary way to the rotor hub, with
rotation axis sensibly parallel to its own longitudinal axis.
 The control mechanisms allow the pilot to change the pitch
of each blade with the cyclic control lever, with respect to the
average value determined by the collective control, in order to
create pitch differences symmetrical to this average value, in
positions diametrically opposed to the rotational axis, inducing
the rotor disk to tilt, thus causing the helicopter to move in the
corresponding direction of tilting.
 Rotors are usually manufactured according to multiple
solutions, all of which, in order to guarantee correct operation,
require the blades to be identical in terms of entity and mass
distribution and as similar as possible in terms of shape and
aerodynamic behaviour, while the joints at the rotor head and the
kinematic chain that controls their pitch must have the same
characteristics for all the blades of the rotor. Therefore, in
order to maintain acceptable performance, such rotors require
frequent maintenance works of blades tracking and balance,
involving complicated procedures and methods and using special
 In such multi-blade rotors, the lifting surface is divided
between the blades of the rotor. With the same diameter and
solidity, in a multiblade rotor each blade has a shorter mean
chord which, for a given rotor tip, results in a lower value of
the ratio between the product of the speed multiplied by the chord
and the kinematic viscosity of the air (Reynolds Number). Since
this lower value results in an increased blade drag coefficient
for a given lift, it is therefore convenient to reduce the number
 Moreover, it must be stressed that the rotation of each
lifting blade produces a wake that can disturb the following
blade, especially during hovering or low speed flight, with
negative effects on its performance. The time interval between the
passage of one blade in a disk area and the following as the
number of rotor blades decreases, under given conditions, thus
reducing the perturbation of the air in which the rotor operates.
 In view of the above considerations, whenever possible, the
adoption of a reduced number of blades can give aerodynamic
advantages over similar rotors with a higher number of blades.
Moreover, the reduction in the number of blades decreases the
number of components and moving parts, leading to the simple
bi-blade rotor with suspended hub connected to the mast with a
horizontal hinge normal to the rotation axis.
 Experiments have also been carried out with single-blade
rotors in which the blade is balanced by a counterweight, but the
difficulties in obtaining an acceptable balance between the forces
and moments acting on such rotors under various operating
conditions have not allowed the application and diffusion of such
 The main purpose of the present invention is to overcome
the inconveniences found in multi-blade and single-blade
helicopters of known type, by means of a main rotor system for
helicopters consisting of a single blade with central hub, a
counterweight and balancing devices, having high flexibility and
adaptability and characterised by easy construction, safe use and
 The second purpose of the present invention is to create a
single-blade rotor system, with working mechanism, in which the
balance of the forces and moments acting on its parts is obtained
by means of the reciprocal positions assumed by these parts as the
coning angle of the single blade varies. The mechanisms
controlling rotor balancing may be kinematic systems of known
type, or other electromechanical or hydraulic devices. In any
case, the horizontal component of the lift of the single blade is
balanced by an identical opposed misbalance of centrifugal
inertial forces, obtained by moving the rotor centre of mass
relative to its rotation axis.
 The third purpose of the present invention is to devise a
rotor system, with control mechanisms, which does not require
blades-tracking to ensure correct operation.
 Last, but not least, another aim of the present invention
is to design a mechanism capable of creating and maintaining a
stable balance between the elements of the single-blade rotor
 These and other aims, which will be highlighted in the
description below, can all be achieved by the present invention.
 Further characteristics and advantages of the invention
will become more evident from the following description of three
different embodiments, with reference to the enclosed drawings,
which are intended for purposes of illustration and not in a
limiting sense, whereby:
 FIG. 1 is a schematic side view of the single-blade
rotor and the devices used to maintain the balance, normal to
the rotational axis of the rotor and the longitudinal axis of
the blade according to a first embodiment;
 FIG. 2 shows the same embodiment in an exploded
 FIG. 2A is a view of the friction devices;
 FIG. 3 and 4 are the same as FIG. 1, with the rotor
blade inclined at a given coning angle;
 FIG. 5 is a schematic side view of the single-blade
rotor and the devices used to maintain the balance, normal to
the rotational axis of the rotor and the longitudinal axis of
the blade according to a second embodiment;
 FIG. 6 is a schematic side view of the single-blade
rotor and the devices used to maintain the balance, normal to
the rotational axis of the rotor and the longitudinal axis of
the blade according to a third embodiment.
 The above figures show that the hub (1) of the rotor is
joined to the support (14) of the blade (8) and made up of a
vertical pair of plates (1a and 1b) symmetrical to the mast (7).
The blade (8) is joined to the support (14) by a pitch hinge of
known type, so that the blade can rotate around its longitudinal
axis A-A, changing its geometrical pitch through joints and
devices of known type, very similar to those generally used in
helicopter rotors, applied to the pitch horn (9) of the blade,
controlled by the rod (10).
 The blade (8) is also fitted with a hinge, of virtual type
also, with axis B-B in vertical and eccentric position with
respect to the axis Y-Y of the mast which allows it to assume an
angular position in the plane orthogonal to the rotational axis
Y-Y, the said hinge being equipped with a damper or similar known
 The two plates (1a and 1b) making up the hub (1) contain
two holes (1c) on the same axis R-R in which the cylindrical body
(2) is coupled in a rotary way, the said body being centrally
hollow and coupled in a rotary way also to the top of the mast (7)
by means of a pair of opposing pins (7a), appropriately provided
with friction devices 30, 31, with axis X-X normal to the same
mast. The two opposite sides of the cylindrical body (2) also
house two rotating coaxial cylinders (3) with axis T-T eccentric
to the other axis R-R and X-X in a rotary way. The cylinders (3)
are housed in an opposing coaxial pair of eccentric holes (2b)
located in the aforementioned hollow body (2), which features
another opposing coaxial pair of holes (2a), housing the pin (7a)
 These cylinders (3) are in turn connected through revolving
eccentric pins (4) to two pairs of identical levers (5) of the hub
(11) of the counterweight, comprising the hub (11) placed at the
end of an arm (12), featuring a profiled mass (13) at the other
 The hub (11) is hinged in a rotary way to the rotor hub (1)
by conaxic hinges (6) with appropriate friction devices, normal to
the longitudinal axis of the counterweight; the joining of the
centre of the pins (6) with the barycenter of the counterweight
(13) determines a direction C-C. The hinges have threaded ends
 More exactly, the hinges (6) are housed in two opposite
coaxial holes located on the plates (1a and 1b) of the hub (1)
along an axis W-W parallel to, but underlying, the axis X-X.
 When the blade rotates without lift (FIG. 1), it rotates in
almost the same horizontal plane as the counterweight , whose axis
is formed by extending the axis A-A.
 When the pilot increases the geometrical pitch of the
rotating blade with the collective control, the lift inclines the
blade upwards at a coning angle ([beta]) such that the lift
balances with the other forces and moments acting on the blade
(FIG. 3). When executing this movement the blade (8) drags the hub
(1) to which it is joined, which rotates around the axis (R-R) of
the cylindrical body (2) at a corresponding angle ([beta]).
 The rotation also takes place with respect to the
counterweight, which maintains its longitudinal axis orthogonal to
the rotation axis Y'-Y' of the rotor. Thanks to this relative
motion, the cylinders (3) linked by the revolving eccentric pins
(4) to the levers (5) of the counterweight and the cylindrical
body (2), coupled in a rotary way to the hub (1) rotate around
each other, determining a new position of the hub (1) relative to
the rotational axis Y-Y, along the direction C-C, passing through
X-X that is, a different position of the rotor centre of mass with
respect to the rotational axis. Since the lift is perpendicular to
the blade, the coning of the blade involves a horizontal component
of the lift, directed towards the centre of rotation. The
horizontal force composes with the inertial forces affecting the
blade and the counterweight. By appropriately dimensioning the
relative positions of the pins (4), the hinges (6) and the axes
R-R, X-X, T-T using known calculation methods of known type and
considering the masses and positions of the relative barycentres
of the blade, counterweight and the other components of the rotor
and the mutual joints, it is possible, within the normal range of
coning values to set up a sufficiently approximate and stable
balance which remains constant on variating the coning angle and
is practically independent of the rotational speed of the rotor,
since the forces that act on the rotor-whether due to lift or
inertia-all proportional to the square of the rotational speed.
 The pitch variations, caused by the pilot acting on of the
cyclic control from the pilot or determined by the asymmetry of
the air flow investing the blade during horizontal flight, cause
the rotational plane of the counterweight to tilt, with consequent
tilting of the entire rotor around the axis X-X, as illustrated in
FIG. 4, thus allowing the helicopter to be moved and controlled.
 FIG. 5 illustrates a second embodiment-but not last-of the
present invention in which the displacement of the rotor centre of
mass relative to the rotational axis Y'-Y' and along the direction
C-C, in order to balance the horizontal component of the lift, is
carried out by an electromechanical actuator (15) acting between
pins (16) and (17), respectively joined to the hub (1) of the
rotor and the cylindrical body (2), which is in turn coupled in a
rotary way with the hub, electrically controlled by a control box
(18) according to the value detected and transmitted with
electrical signals by the telescopic detection device (19) of
known type of the relative distance assumed by the points (20) and
(21), in relation to which the detector (19) is respectively
hinged to the hub (11) of the counterweight and the hub (1) of the
rotor, as the coning of the blade (8) changes.
 In fact, the control box is designed and programmed using
known calculation methods and construction systems, so that for
each coning value of the blade, as measured by the detector device
(19), the actuator (15) causes the cylindrical body (2) to rotate
around the hub (1) so that the rotor centre of mass relative to
the rotation axis, passing through X-X, assumes the correct
position to ensure balance between the aerodynamic and inertial
forces acting on the rotor.
 FIG. 6 illustrates a third embodiment of the present
invention, in which the actuator (15) controlled by the control
box (18) radially displaces the mobile mass (22) that slides on
the rod (12) of the counterweight, according to the coning angle
measured by detector (19), thus changing the position of the rotor
centre of mass relative to the rotational axis of the rotor.
 The actuator (15) is joined by hinging pins (16 and 16a) to
one of the plates of the hub (1) and to the mobile mass (22).
 In this construction version the two plates of the hub (1)
only show two opposing holes (23) located along the same axis X-X
perpendicular to the rotational axis Y-Y of the rotor. The holes
(23) house the pins (7a) located at the top of the mast (7).
MECHANISM FOR BALANCING SINGLE BLADE AIRCRAFT ROTOR
Uniblade air rotor and flight and hovercraft vehicles
The invention is related to air flight vehicles, such as
vertical take-off and landing (VTOL) airplanes, helicopters and
covercraft.The goal of this invention is to create an air rotor
designed so that while after vertical take off or cover regime,
one can be stopped, fixed in a specific position and hidden into
the fuselage (gondola) thus eliminating of air resistance when the
rotor is not in working state. On landing this rotor can be
extended out, brought into rotation and used for creation of lift
force and vertical landing.The indicated goal is achieved by means
of the rotor made as single blade (uniblade). The author solved
the problem of force and moment balance of single blade. The
center of gravity of the counterweight is located below the
horizontal plane, and the blade has the horizontal sway axle, that
crosses the vertical rotor rotation axis. The author offer this
rotor on single axis, on co-axis, and on different exiles.This
uniblade rotor is designed to subsonic and supersonic VTOL
airplanes, for helicopter cars, flight motorcycles, hoppycopters,
and hovercraft.The uniblades be used also as a veritable sweep
wing (for subsonic and supersonic aircraft).
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is related to air flight vehicles, such as
apparatus of vertical take off and landing (VTOL), helicopters,
covercraft, flighting automobiles, motorcycles, and traditional
2. Description of the Related Art.
Known in art are helicopter rotors having 2, 3, 4, 6 and more
blades (Jane's Aircraft Directory, 1995-1996), (FIG. 1a-d).
Requirement of 2 or more blades is dictated by the blades
aerodynamic force and weight balance. Total resultant lift force
of blades thrust must act along blade axis O (FIG. 1) and blades'
centrifugal force must be balanced, while the blade horizontal
axis Oi is located close to vertical axis O, but Oi and O do not
cross each other (FIG. 1e).
BRIEF SUMMARY OF THE INVENTION
The goal of this invention is to create an air rotor designed so
that while in flight, it can be stopped, fixed in a specific
position and hidden into the fuselage (gondola0 thus eliminating
air drag when the rotor is not in working state.
On lending this rotor can be extended out, brought into rotation
and used for creation of lift force and vertical landing.
The indicated goal is achieved by means of the rotor made as
single blade (uniblade). The center of gravity of the counter
weight B (FIG. 2) is located below the horizontal blade plane, and
blade has the horizontal sway axis O1 that crosses the vertical
rotor's rotation axis O (FIG. 2a).
Uniblade rotor has huge advantages when compared to a helicopter
rotor with 2,3 of more blades. The uniblade rotor can be stopped
(in direction of air stream) and moved in to the fuselage
(gondola). In hidden position, the uniblade rotor does not
interfere with the air flow whereby the air vehicle can reach
designed speed, even supersonic speed. On landing, the uniblade
rotor is easy to move out of the fuselage, bring into rotation and
make landing in helicopter mode.
However, the uniblade rotor posses a problem of the blade
balancing. The most important of which is that large unbalanced
blade lifting force P rotates along circumference Q together with
the blade at angular speed .omega. (FIG. 2b) and creates large
capsizing moment, direction of which also changes (rotates).
In order to eliminate these negative effects, the inventor
proposes to place the blade counterbalance B. The counter balance
gravity center is shifted down (distance CB in FIG. 2a) from the
blade plane, and for elimination of the capsizing moment, the axis
of horizontal swing O of the blade is located so that it crosses
rotation axis O of the engine power drive.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1. Existing 2- and 6 blade rotors, blade swing axis O
and balancing scheme of lifting force P=.SIGMA.Pi.
FIG. 2. Uniblade rotor and arising problems of unbalanced
lifting and centrifugal forces. P is blade's lifting force. Q is
circular trajectory along which lifting force P moves. B is
counterbalance. F1, F2 are centrifugal forces of the blade and
counterbalance correspondingly. CB is shift distance of the
counterbalance center of gravity down from the blade plane. O1
is rotor axis. O is blade swing axle.
FIG. 3. Diagram of balancing of the blade lifting force P,
capsizing moment M and centrifugal force F1. The balance is
attained due to shifting the counterbalance down and placing
swing axle O at the rotor rotation axle,
FIG. 4a. Co-axle uniblade rotor. KL is meeting line of
synchronously rotating blades. Line KL is positioned in the
direction of flight. Angular speeds of the blades are equal to
each other., i.e. .omega.1 =.omega.2. Such meeting line KL
provides small distance between the uniblades.
FIG. 4b. Uniblade rotor with turning blade at the end of
main blade. That may be used for covercraft--helicopter which
used ground effect. 1 --main uniblade, 2 --turning blade at end
of the main blade, 3 --counterbalance, 4 --hinge of the blade
swing axle, 5 --axis of the turning blade, 6 --sensor of
distance from blade to barrier (for example, ultrasonic sensor),
7 --ground, 8 --direction of turn of additional blade, 9
--trajectory of the end of additional blade, 10 --trajectory of
main blade, 11 --hinge.
FIG. 5. Sketch of the synchronously rotating uniblades
rotors rotated in opposed directions, which have different axis.
Meeting line KL is located in perpendicular direction of flight.
The such uniblade rotors provide small distance between the
FIG. 6 Supersonic helicopter--airplane (supersonic VTOL
Fighter) with uniblade retracted rotor. a) 1--single-blade
propeller; 2--sliding stand; 3--jet streams from jet engines,
equalizing the reaction of the propeller; 4--superstructure for
retracting the propeller; 5--hatches.
b) Supersonic helicopter--airplane with retracted single
FIG. 7. a) Subsonic transport/passenger VTOL airplane with
b) Airplane with retracted rotor.
d) Airplane with retracted uniblade.
FIG. 8. Small subsonic passenger VTOL airplane with
FIG. 9. Flight car with co-axes uniblade rotors.
FIG. 10. Motorcycle with co-axle uniblade rotors.
FIG. 11. Hoppycopter (knapsack helicopter) for young
people, sportsmen, and soldiers with small co-axis uniblade
FIG. 12. a) Supersonic VTOL airplane with two co-axis
uniblade rotors using in horizontal flight as variable swept
wings. B--counter balance weight.
b) Airplane in flight.
FIG. 13. a) Supersonic airplane with uniblade rotor using
also as variable swept wing.
b) Airplane in flight.
FIG. 14. The covercraft--helicopter with co-axile uniblade
rotor which has the turning blade at the end of the main blade.
FIG. 15. Mechanism of folding for uniblade.
a) 1--uniblade, 2--hinge, 3--lock, 4--hinge of blade swing
exile, 5--main exile, 6--counterbalance.
b) Uniblade in folding (variant 1).
c) Uniblade in folding (variant 2).
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 2, uniblade rotor comprises blade 1,
counterbalance B, horizontal axle of blade swing O situated in the
blade plane and crossing vertical drive axle O. Counterbalance B
is shifted down at distance CB from the blade plane. This distance
CB could go to zero in limit in presence of axle O.
The uniblade rotor work as follows. Lift force P (FIG. 2) created
by a rotating blade, causes moment M (FIG. 3) that tends to rotate
the blade counter-clockwise. Counterbalance centrifugal force F
(FIG. 2a), due to the counterbalance shifted down, also creates
counterweight moment M (FIG. 3) with direction opposite to moment
M (FIG. 3).
Resultant lift force P acts along drive rotation axle ) and
balances flight vehicle weight G (FIG. 3). The blade and
counterbalance centrifugal forces F1 and F2 are also balanced, F1
Co-axial uniblade rotors rotate synchronously and meet on line KL
of movement direction of the flight vehicle (FIG. 4). In this
position the blades are parallel to each other which makes it
possible to keep distance between the blades (unirotors) small,
actually much smaller than in traditional co-axial multiblade
helicopter propellers. This results in uniblade having
significantly simpler design and increased rotor efficiency.
The main blade can has the additional small blade at the end (FIG.
4b). That may be turning or interning. This end blade increase the
rotor efficiency and trust about ground. The trust and ratio of
fuel depend strong from distance, which is from the end of
additional blade to ground. The trust may increase in 2-6 times.
It is important for covercraft-helicopter (FIG. 14). In regime of
cover this vehicle can move over marsh, river, sand. And in regime
of helicopter one can flight over forest, precipice, mountains and
The end blade has a sensor of distance from end of additional
blade to ground, for example, ultrasonic sensor. The additional
blade can rotate and follow to profile of ground surface (see FIG.
The uniblade can be make of folding (FIG. 15). That can have hinge
2 and lock 3. The folding may used on flying car, motorcycle,
holycopter, covercraft and military VTOL airplanes and
As you see on FIG. 15c the size of aircraft may be decreased more
than two times, and request area for storage in 4 times.
In case of a coupled rotor, thanks to only one blade in the
uniblade rotor, distance between axles of the two uniblade rotors
can be made smaller than in multiblade variant. In this case the
meeting line KL (of the synchronously rotating rotors) is
perpendicular to flight direction (FIG. 5).
Various versions of the uniblade use are shown in FIGS. 6 to 13.
FIG. 6 shows a supersonic fighter aircraft with the uniblade
rotor. The rotors reaction here is balance by the gas jet of the
aircraft. FIG. 7 shows the subsonic transport VTOL airplane having
the uniblade rotor reaction of which is balanced by the
single-blade tail propeller. FIG. 8 shows the small subsonic
passenger VTOL airplane with uniblade rotor. FIG. 9 shows the
flight car with co-axial uniblade rotors. One can be used as
helicopter and as a car. FIG. 10 shows the flight motorcycle for
young people. One can be used as a helicopter and as a motorcycle.
FIG. 11 shows the small knapsack helicopter (hoppycopter) for
young people, sportsmen, and soldiers with uniblades co-axial
rotors. It can be put on shoulders of man and allow people to flay
with maximum speed 50 mph (80 km/h), in ceiling of 12000 foot
(4000 m), and range of 100 miles (160 km). FIG. 12 shows high
speed vertical takeoff and landing airplane having co-axial rotors
blades of which serve as variable geometry wings.
The blade of the uniblade rotor may have such a form of the widen
part where the counterbalance is placed, that the resultant of
lift force pressure and resistance is located at the vertical
connecting axle. Thanks to this blade in the stopped position can
work in flight as a high-speed variable swept wing (FIG. 13).
The uniblade rotor can have a mechanism for breaking, stopping,
moving into the fuselage and moving out of the fuselage and
rotating--all can be done in flight. Moreover, a mechanism for the
rotor move-out operations can be made as either movable axle or as
sliding axle of varying length. In removed state, the rotor does
not create any drag and speed of the air vehicle can reach its
designed value, including supersonic level. On landing, the rotor
is moved out of the fuselage and starts rotating. It must be noted
that this is possible only with a single-blade (uniblade) rotor.
For rotors with 2, 3 or more blades, it is practically impossible
to design in-flight rotor stopping and removal mechanism. The air
stream would immediately destroy rotor, or topples a flight
vehicle. Moreover, it is very difficult from a technical point of
view, to move in and move out several blades.
Even with out hiding an uniblade rotor in flight, the single blade
is positioned along the air stream and creates a little drag.
Dimensional sizes of an flight vehicle with the uniblade rotor is
less than sizes of a helicopter, and the apparatus can be quickly
prepared for flight.
Result of the Patent Investigation
Patent are close to topics "Uniblade Air Rotor for Flight
Inventor: Alexander Bolonkin
U.S. Pat. No. 5,074,753 Rotor blade
U.S. Pat. No. 4,434,956 Flexible helicopter rotor
U.S. Pat. No. 4,129,403 Helicopter rotors
U.S. Pat. No. 3,902,821 Helicopter rotors
U.S. Pat. No. 4,099,812 Helicopter rotors
U.S. Pat. No. 5,199,851 Helicopter rotor blades
U.S. Pat. No. 4,316,700 Helicopter rotor blades
U.S. Pat. No. 4,427,344 Helicopter rotor blade
U.S. Pat. No. 4,652,211
U.S. Pat. No. 4,588,356
U.S. Pat. No. 4,549,851
U.S. Pat. No. 4,540,340
U.S. Pat. No. 4,512,717
U.S. Pat. No. 5,320,494
U.S. Pat. No. 4,549,850
U.S. Pat. No. 4,543,040
U.S. Pat. No. 4,516,909
U.S. Pat. No. 4,509,898
U.S. Pat. No. 5,246,344
U.S. Pat. No. 5,205,851
U.S. Pat. No. 5,195,851
U.S. Pat. No. 5,174,721
U.S. Pat. No. 4,975,022
U.S. Pat. No. 4,808,075
U.S. Pat. No. 4,714,409
U.S. Pat. No. 4,668,169
U.S. Pat. No. 4,551,067
Everel Propeller Corporation
[ Machine Translation ]
The invention relates to a single leaf screw disposed on a drive
shaft with an extension shaft, the vane disposed counterweight
that is disposed perpendicular to the drive shaft, so that the
blade screw about its own in extending the service of the
underpinning axis located. Said Influence of centrifugal force and
also under the influence of air resistance can be pivoted.
The drawings. an exemplary embodiment of the subject invention:
Figure 1 shows a schematic view of such a thumbscrew, Figure 2 is
an elevational view of the screw; FIG, 3 is a vertical
cross-section of middle, 3 = 3, Figure 4 is a horizontal sectional
view 4 - .4, Figure 5, 6 and 7 are views. of different end
positions of the wing screws, and indeed is the wing with respect
to the axis about which it rotates in different angles, shown with
Figure 5, the smallest Indicating the slope wing, so that when the
air pressure is high, which corresponds to the air pressure at,
sea level. Figure 6 represents an average slope, and 7 so twisted
the wing that he has the highest possible pitch....
Screw drive with a speed considerably above that speed the level
at which the efficiency level of a normal, screw with two or three
blades is achieved. That is therefore beneficial because the
engines nods its highest efficiency at that speed reach speed that
is best just for the wing screw.
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