Patent Application
20170355452
The present invention broadly relates to aircraft landing gear and aircraft carrying such landing gear and methods associated with the same.
The world's population is increasing. As such more people are around and therefore there is more people travelling. Some prefer to travel between places efficiently. Some prefer to travel to remote places. One form of transportation used more and more is flying, whether long haul in large aircraft with a carrying capacity of 100 people or by way of medium to small sized aircraft for short distances and/or where as few as 1 or 2 people are carried. As such there is an increasing demand on airports to increase their capacity to allow more aircraft to land, more pressure to increase airspace, flight paths and/or to build more airports in places that would otherwise not have accommodated airports. Therefore there are more aircraft in the airspace than ever before and this is set to continue. At times the weather can be inclement. Despite this, there is a need to ensure flight schedules are maintained and an increasing demand has been placed on pilots to land in such inclement weather, including strong cross winds, where otherwise landings would not be allowed or would not be possible. Landing in cross wind situations can be difficult, even for skilled pilots. With more recreational pilots joining the air, landing in small airports that may sometimes be unmanned, or remote places that may only be accessed by water is prevalent. These recreational pilots may need to land in inclement weather where strong cross winds prevail and then to take off on water or land yet many aircraft may be restricted to land in such conditions or require a great deal of skill to land safely.
Therefore there is a need to provide aircraft landing gear of or for an aircraft that is able to address the problems identified above.
Accordingly in a first aspect the present invention may be said to broadly be an aircraft comprising
Preferably the caster assembly comprises a caster axle mounted for rotation on a caster axis that is parallel a vertical plane passing through the aircraft's longitudinal axis.
Preferably the caster axis is parallel the aircraft's vertical axis.
Preferably the undercarriage is the primary aircraft weight bearer.
Preferably the landing wheel is the primary aircraft weight bearer.
Preferably the landing wheel is positioned forward of the centre of gravity of the aircraft.
Preferably the fuselage is an elongate fuselage extending along the aircraft's longitudinal axis, the caster assembly comprises a caster axle mounted for rotation on a caster axis that is parallel a vertical plane that passes through the longitudinal axis.
Preferably the caster axis lies in the vertical plane.
Preferably at least two caster assemblies are provided, each mounting a respective landing wheel.
Preferably at least two caster assemblies are provided each mounting a respective landing wheel to provide a landing wheel more proximate the nose of the aircraft and a landing wheel more proximate the tail of the aircraft.
Preferably a first landing wheel is positioned forward of the centre of gravity of the aircraft and a second landing wheel is positioned aft of the centre of gravity of the aircraft.
Preferably each caster axis of each caster axle are parallel each other.
Preferably the caster axis of each caster axle are not all parallel each other.
Preferably the aircraft comprises one said caster assembly mounting a landing wheel more proximate the nose of the aircraft and one landing wheel more proximate the tail of the aircraft.
Preferably the one landing wheel more proximate the tail of the aircraft does not caster and has its rotational axis parallel the aircraft's lateral axis.
Preferably the landing wheel is mounted for rotation by said caster assembly about a wheel axis.
Preferably the wheel axis is able to rotate at least partially around the caster axis, when the landing wheel casters about the caster axis.
Preferably when the wheel axis is perpendicular the aircraft's longitudinal axis when seen in plan view, the aircraft when moving forward on land, will travel in a direction (track) coincident the aircraft's longitudinal axis.
Preferably when the wheel axis is not perpendicular the aircraft's longitudinal axis when seen in plan view, the aircraft when moving forward on land, will travel in a direction (track) at an angle to the aircraft's longitudinal axis.
Preferably the wheel axis lies in a plane that is parallel a plane in which the aircraft's longitudinal and lateral axes lie.
Preferably at least one arm extends between the caster axle and the landing wheel to mount said wheel in manner able to be able to caster.
Preferably the at least one arm carries a wheel axle coaxial the wheel axis and about which the wheel can rotate.
Preferably the caster assembly can, in a first condition, allow the landing wheel to freely caster and in a second condition, cause the wheel to be coupled to pilot controlled steering input that can control the operative rolling direction of the landing wheel when the aircraft is travelling on land.
Preferably the caster assembly can, in a first condition, allow the landing wheel to freely caster and in a second condition, causes the caster axle to be coupled to pilot controlled steering input that can control the operative rolling direction of the landing wheel when the aircraft is travelling on land.
Preferably when coupled to pilot controlled steering input the wheel axis can be caused to move about the caster axis by said steering input.
Preferably the wheel axis can move about the caster axis within a limited range of movement.
Preferably the caster assembly in a first condition allows the landing wheel to freely caster and in a second condition is coupled to a steering mechanism of said undercarriage.
Preferably the steering mechanism is operatively connected to pilot operable steering input (eg foot pedals) that (a) when the caster assembly is in its first condition, is decoupled from the caster axle and (b) when moving from the first condition to the second condition of the caster assembly, by an upward movement of the caster axle relative the fuselage displace, can cause the steering mechanism to couple with the caster axle.
Preferably the steering mechanism includes a steering block engaged to a steering arm that is operatively connected to pilot operable steering input (eg foot pedals), the steering block and caster axle mounted for relative movement to each other to (a) allow relative rotation about the caster axis when the caster assembly is in its first condition and (b) allow relative displacement in the caster axis direction when the caster assembly moves between its first and second conditions.
Preferably the steering block is mounted about the caster axle.
Preferably the steering block has a hole thought it, in which the caster axle is located.
Preferably the steering block and the caster axle are able to couple together when the caster assembly is in the second condition to rotationally move together, by virtue of engagement of complimentary key and recess features of the caster axle and steering block.
Preferably the key feature is a pin extending radially said caster axis and said recess is provided in a surface of said steering block.
Preferably the caster assembly is biased to said first condition and only upon contact with land by said landing wheel, is the caster assembly moved towards the second condition.
Preferably such contact with land results in the wheel bearing aircraft weight of a sufficient amount to overcome the bias.
Preferably the caster assembly can, when in a first condition, allow the landing wheel to freely caster but under the influence of a rotational bias that, when the aircraft is travelling forward on land, encourages the wheel to move to an operative rolling direction that causes the aircraft's longitudinal axis to be coincident its direction of travel (track).
Preferably when in the second condition, the landing wheel is no longer under the influence of said rotational bias.
Preferably the aircraft longitudinal axis is coincident the aircraft heading.
Preferably the aircraft's rudder and steering mechanism are coupled so that when the aircraft is landing in a crabbed condition and the rudder is position to maintain the aircraft on track, the steering mechanism cannot couple to the caster axle when the landing wheel's rotational axis is perpendicular to the track of the aircraft.
Preferably the caster axle of a first caster assembly is coupled to a caster axle of a second caster assembly in a manner to transfer torque between caster assemblies about respective caster axes.
Preferably a torque transfer mechanism is provided between adjacent caster assemblies.
Preferably each caster assembly has a torque arm extending radially from said caster axle, the torque arm of one caster assembly coupled to the torque arm of another caster assembly.
Preferably the aircraft is an amphibious aircraft as herein described.
Preferably the landing wheel(s) is/are the primary load bearing wheel(s) of the aircraft when on land.
Accordingly in a second aspect the present invention may be said to broadly be an aircraft with an undercarriage of a plurality of aircraft centreline mounted landing wheels able to be controlled for steering the aircraft by the aircraft's pilot when travelling on land, in manner what causes each landing wheel to be turned differentially.
Preferably the wheels are mounted to be able to be so controlled in one mode and in a second mode are able to passively caster relative the aircraft centreline.
Accordingly in a third aspect the present invention may be said to broadly be an aircraft with an undercarriage of a plurality of centreline mounted landing wheels able to be controlled for steering the aircraft when travelling on land in manner what causes each wheel to be turned so that each wheel's rotational axis converges at centroid when seen in plan view.
Preferably the wheels are mounted to be able to be so controlled in one mode and in a second mode are able to free caster relative the aircraft centreline.
Accordingly in a fourth aspect the present invention may be said to broadly be an aircraft comprising
Preferably the landing roller is selected from one of a wheel and a track assembly that comprises a roller wheels mounted track.
In a further aspect the present invention may be said to broadly be an amphibious aircraft comprising a primary fuselage presenting a hull form extending along the aircraft centreline to support the amphibious aircraft on water, and at least one landing wheel mounted at and partially yet sufficiently exposed from a recess in the hull form to be able to support the amphibious aircraft, including for landing and take-off, on land.
In a further aspect the present invention may be said to be an amphibious aircraft comprising a primary fuselage presenting a hull form along the amphibious aircraft centreline to support the aircraft on water, and at least one landing wheel mounted at the hull form and always presented to be able to support the aircraft, including for landing and take-off, on land.
Preferably the landing wheel is mounted in a recess of the hull form and partially yet sufficiently exposed from a recess in the hull form to be able to support the amphibious aircraft.
Preferably the at least one landing wheel has its rotational axis positioned inside the recess and less than half the wheel is exposed from the recess outside the hull form.
Preferably less than one third of the at least one landing wheel is exposed from the recess outside the hull form.
Preferably said at least one landing wheel is positioned at the centreline of the amphibious aircraft.
Preferably the at least one landing wheel is always presented in a manner capable of landing and support of the amphibious aircraft on land.
Preferably said amphibious aircraft comprising an undercarriage that includes said at least one landing wheel.
Preferably the undercarriage allows the wheel to translate between an up and down position, both said up and down positions presenting said at least one landing wheel in a manner capable of landing and support of the amphibious aircraft on land.
Preferably the undercarriage is secured to the hull form in the recess.
Preferably the undercarriage is located in the recess save for at least part of the at least one landing wheel being exposed from the recess outside the hull form.
Preferably said undercarriage includes a caster assembly mounting said at least one landing wheel in a manner able to caster.
Preferably the caster assembly mounts said at least one landing wheel so that it can caster to allow the amphibious aircraft to land on land in crabbed condition and travel over and in contact with land in such crabbed condition.
Preferably the caster assembly can, in a first condition, allow the at least one landing wheel to freely caster and in a second condition, causes the caster axle to be coupled to pilot controlled steering input that can control the operative rolling direction of the landing wheel when the aircraft is travelling on land.
Preferably said first condition corresponds to said wheel being in said down position and said second condition corresponds to said wheel being in said up position.
Preferably when in the up position, the wheel is coupled to pilot controllable steering input.
Preferably when in the down position, the wheel is able to freely caster yet be biased towards one rotational caster position.
Preferably the wheel is biased towards the down position (eg by gravity and/or a spring).
Preferably there are a plurality of landing wheels, each positioned along the centreline of the aircraft.
Preferably each landing wheel is positioned in a recess of said hull form.
Preferably at least two landing wheels are positioned in a recess of said hull form.
Preferably a plurality of recesses are provided in said hull form, at each of which at least one said landing wheel is positioned.
Preferably the recess(es) are large enough to allow the landing wheel to caster.
Preferably the fuselage includes sponsons provided to enhance stability of the amphibious aircraft when in water.
Preferably the amphibious aircraft is full time amphibious.
Preferably the amphibious aircraft comprises left and right wings dependent from said fuselage and left and right side stabilisers dependent from one of (a) said fuselage and (b) said left and right wings, each adapted and configured to hydroplane when water landing and taking off.
Preferably each stabiliser also includes a wheel able to make rolling contact with land when the aircraft is travelling over land.
Preferably the wheel is mounted in a manner to be able to caster when in rolling contact with land.
Preferably each stabiliser is in rigidly fixed to one of (a) said fuselage and (b) said left and right wings.
Preferably each stabiliser is always presented for water and land landing and take-off.
Preferably the aircraft is certified with a maximum gross take-off weight of no more than 1200 kg.
Preferably the aircraft is certified with a maximum gross take-off weight of no more than 1000 kg.
Preferably the aircraft is a 4 seater aircraft.
Preferably the aircraft is certified with a maximum gross take-off weight of no more than 1000 kg.
Preferably the aircraft is certified with a maximum gross take-off weight of no more than 800 kg.
Preferably the aircraft is certified with a maximum gross take-off weight of no more than 700 kg.
Preferably the aircraft is certified with a maximum gross take-off weight of no more than 650 kg.
Preferably the aircraft is a 2 seater aircraft.
Preferably the hull form provides all the needed buoyancy to float the aircraft in fresh water at any of these maximum take-off weights.
Preferably the hull form includes the sponsons.
Preferably hull form includes a bow and a stern.
Preferably the bow has a V-shaped entry
In a further aspect the present invention may be said to broadly be an aircraft having a plurality of landing wheels each mounted in a manner able to caster so that in a cross wind approach of said aircraft to a run way, the aircraft is able to land in a crabbed condition and the landing wheels are each able to caster to roll in the track direction of the aircraft upon landing.
Preferably all said wheels are able to caster.
Preferably a plurality of caster assemblies are provided secured so the fuselage of said aircraft and each mounting at least one caster wheel in a manner to caster about a respective caster axis.
Preferably all landing wheels are positioned along the centreline of the aircraft.
Preferably castering of said wheels is passive.
Preferably at least the wheel rear most of the aircraft is able to be actively braked.
Preferably each wheel is able to be braked, the braking occurring in a progressive or graduated manner with each successive wheel front to back being subjected greater braking force.
Preferably progressive or graduated braking caused the aircraft to de-crab during landing and after touch-down of the landing wheels.
Preferably the wheels are coupled to each other to caster in unison.
Preferably the landing wheels are always presented for landing on land.
Preferably the landing wheels do not move between a retract and deployed position.
Preferably the aircraft is an amphibious aircraft.
Preferably the aircraft is an amphibious aircraft as herein described.
In a further aspect the present invention may be said to broadly be landing gear of or for an aircraft comprising:—
at least two trucks placed in-line with the longitudinal direction of the fuselage of said aircraft each truck provided with at least one wheel presentable relative to the fuselage to make rolling contact with ground to at least partly support the weight of the aircraft,
a steering input engagement mechanism to selectively couple with at least one wheel to assist with the directional control of said aircraft whilst moving over the ground,
wherein at least the forward most wheel is mounted to be able to caster about a caster axis, when in rolling contact with the ground.
Preferably the coupling of the engagement mechanism with the wheel is by indirect engagement with the wheel.
Preferably the fuselage includes a recess at the underside of the fuselage of said aircraft for each of said trucks and engagement mechanism, to house each of the truck and engagement mechanism in said housing.
Preferably the wheel in part of a caster wheel assembly that holds said wheel in a manner able to turn about its own axis of rotation and that includes a caster axle mounted relative said fuselage for rotation about a caster axis that lies in a plane to which the axis of rotation of the wheel is normal to.
Preferably the plane is coincident the longitudinal axis of the aircraft.
Preferably the caster axis is coaxial the caster axis.
Preferably at least the forward most wheel is able to caster about a caster axis substantially perpendicular to said longitudinal axis of said aircraft.
Preferably the engagement mechanism is able to couple with said wheel(s) to control rotation of the wheel(s) about the caster axis only when the aircraft rudder is in a position that would cause the aircraft to travel in the same direction in the air as the wheels would when in rolling contact with the ground.
Preferably the engagement mechanism so couples with the wheel when at least some of the aircraft's weight is being borne by the wheel.
Preferably the engagement mechanism is not coupled with the wheel when the aircraft is airborne.
Preferably one truck of said at least two trucks is placed towards the forward end of said fuselage and the other truck placed more towards the rear end of said fuselage.
Preferably each wheel of each truck is mounted to be able to caster when in rolling contact with said ground.
Preferably the wheel(s) are controlled for rotation about their caster axis by pilot input control to steer the aircraft when the engagement mechanism is coupled to the or each wheel.
In a further aspect the present invention may be said to broadly be landing gear to assist in landing of an aircraft on ground comprising:—
a set of trucks substantially placed in-line with the longitudinal direction of the fuselage of said aircraft,
each truck provided with at least one caster wheel assembly comprising at least one wheel that is capable of castering when in rolling contact with ground,
wherein one truck of said set of trucks is substantially placed towards the forward end of said fuselage and the other truck of said set of trucks is substantially placed towards the rear end of said fuselage,
wherein as the aircraft comes into land when the nose of the aircraft is higher than the rear of the aircraft, then the one or more wheels of said rear truck can caster to become aligned to the aircraft track, followed by the one or more wheels of said front truck as its wheel or wheels contact the ground, to allow the aircraft to land and travel on the ground in a crab condition.
Preferably for each truck, the wheels are connected in a manner to caster in unison.
Preferably when said aircraft is in-flight then its heading is substantially controlled by the rudder and air flow over the wings generated by said aircraft engine, jet engine, propeller or the like.
Preferably when in-flight, each wheel is able to freely caster about its respective axis through a 360 degrees.
Preferably when in-flight, each wheel is able to freely caster about its respective axis but limited to a range of rotation of less than 360 degrees.
Preferably free caster movement of the wheels or angle of rotation of each wheel can be limited by for example a spring(s) (including pneumatic, leaf for example), locking arms, brakes, shock absorber(s), bellow(s), dampers, stops or other apparatus capable of preventing the movement and/or shimming of the wheels.
In some embodiments this apparatus capable of preventing movement and/or shimming of the wheels can be provided directly or indirectly to the wheels, the trucks and/or a mount located between said set of truck(s) and fuselage of said aircraft.
In an embodiment when said aircraft is on and travelling over the ground then directional control of said aircraft is primarily assisted by landing gear apparatus which may or may not be further assisted by control of the rudder and/or air flow over the rudder and/or wings generally used for directional control while in-flight.
The engagement mechanism can be automatically or manually controlled (eg by the pilot) of the aircraft. In one embodiment the engagement mechanism is automatic.
In an embodiment the landing gear is attached to amphibious, seaplanes or land only aircraft.
In some embodiments a set of trucks is at least 2 or more and a set can be an uneven number of trucks. In some embodiments the trucks comprise 2 or more sets of wheels. The wheels can be singular or more width wheels. Each set can comprise even or uneven sets of wheels, such as for example, a pairing of 1 or 2 wheels, a pairing of 1 and 3 wheels, a pairing of 2 wheels and 3 wheels, a pairing of 2 and 5 wheels, 3 and 7 wheels. The wheels can contain air, such as the conventionally used aircraft tyres or be airless, such as tweels.
This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.
As used herein the term “and/or” means “and” or “or”, or both.
As used herein the term “(s)” following a noun includes, as might be appropriate, the singular or plural forms of that noun.
Preferred forms of the present invention will now be described with reference to the accompanying drawings in which,
The present invention relates to an aircraft that in one form has landing gear that allows the aircraft to land on land. An example of an aircraft 1 that may carry landing gear as herein described is shown in
The aircraft 1 preferably comprises of a fuselage 2 that includes a cockpit region 3 able to carry a pilot and preferably also at least one and preferably a plurality of passengers. The aircraft also includes primary wings 4a and 4b that may carry appropriate control surfaces (eg ailerons and flaps). The aircraft may also be configured to have a tail wing assembly 5 that may carry appropriate control surfaces such as elevator and rudder control surfaces. A rudder 6 is for example shown in
The wings or fuselage may carry at least one motor 7 that may directly or indirectly drive a propeller 8 or propellers. The control surfaces of the aircraft are able to be controlled by pilot input. For example the rudder 6 may be operable via a linkage mechanism connected to a foot pedal mechanism 45 in the cockpit. The foot pedal mechanism can cause the rudder 6 to turn left and right.
Landing gear 9 is preferably presented at the underside of the fuselage. In a basic form the landing gear of the aircraft comprises of at least one wheel. This at least one wheel is the main weight bearing wheel for when the aircraft is on land. It can support the aircraft on land. Other wheels like it or other support providing members may also be provided to help support the aircraft on land.
In examples of the aircraft shown herein, a plurality of wheels are described. However, in a basic form the landing gear may present only one wheel, that wheel preferably able to caster in a manner as will herein be described.
The provision of one or more wheels able to caster allows the aircraft to land on land in a condition where its heading is not parallel to its track. Eg, it is approaching a runway in a crabbed condition. Such a situation may for example be encountered when an aircraft is landing on a runway and is subjected to a cross wind. The ability for the wheel(s) of the landing gear to caster allows for a or each wheel to contact the runway and caster (eg be pivoted, preferably about a substantially vertical axis) so that a or each wheel's rotational axis is caused to move to a position that is perpendicular to the track of the aircraft. This allows the aircraft, upon landing to remain in a crabbed condition. The wheel(s) will roll on land so that their operative rolling direction is the same as the aircraft's track. This may not be the same direction as the aircraft's heading. De-crabbing of an aircraft landing in a crabbed condition may occur in a gradual manner, whilst in contact with land, as will herein after be explained.
Whilst in one form the aircraft herein described may carry a landing gear comprising of only one wheel that is able to caster as seen in
In a preferred form the landing gear 9 of the aircraft 1 comprises of at least a forward more and a rearward more positioned wheel. Preferably the forward more positioned wheel is forward of the aircraft's CoG and the rearward more positioned wheel is rear of the aircraft's CoG. Preferably there are two sets of wheels engaged to the fuselage, one forward more and one rearward more.
Preferably each set of wheels is provided as part of a landing gear truck formation. There being a front landing gear truck 10a and a rear landing gear truck 10b. Landing gear truck 10a is forward more positioned to the fuselage compared to rear landing gear truck 10b.
Each landing gear truck 10a and 10b carries at least one wheel which is preferably mounted in a manner able to caster relative to the fuselage. In the most basic form it is preferably the wheel or wheels of the front truck that are able to caster when there is only one wheel of the rear landing gear truck 10b. However in the preferred form the wheel or wheels of each truck 10a, 10b are mounted in a manner to be able to caster relative to the fuselage.
In one form the front and rear landing gear trucks carry an equal number of wheels. In other forms that are also herein described the front landing gear truck 10a may carry fewer wheels than the rear landing gear truck 10b.
In the preferred form the wheels are all in-line (though may not be castered in alignment). Preferably the wheels are all positioned along a vertical plane passing through the longitudinal axis of the aircraft.
When the aircraft is travelling on land the ability for the wheel or wheels to caster relative the fuselage is limited and dictated at least by virtue of contact of the wheels with the ground. When the aircraft is in the air the wheels are able to freely caster although as will hereinafter be described such castering whilst the aircraft wheels are not in contact with the ground may in other ways, at least to some extent, be limited.
With reference to
The wheel 11 is mounted for revolution about its rotational axis X by the caster assembly. More than one wheel may be mounted by said caster assembly, each wheel mounted for revolution on a common rotational axis. The caster assembly includes mounting arms 12a and 12b that carry the axle 13 of the wheel, on each lateral side of the wheel. The mounting arms are mounted for rotation around a castering axis YY to allow the wheel to caster relative to the fuselage of the aircraft about the castering axis YY. A caster axle 14 (sometimes also referred to in the art as the caster spindle) may be provided to facilitate such castering. There could be just one arm 12a and no arm on the other side of the wheel. The castering axle 14 is mounted in a manner that will hereinafter be described.
In the preferred form the castering axis YY is oriented substantially vertically relative to the aircraft when it is in a horizontal condition. The axis YY is preferably normal to the surface that the wheel is travelling on, when the aircraft is on land.
In the preferred form the castering axis YY lies in the vertical plane of the aircraft that passes through the longitudinal axis of the aircraft.
However in some forms aircraft may carry caster assemblies that are set side by side rather than in-line. The castering axis are preferably parallel the vertical plane.
The caster axle 14 is mounted by or via a caster wheel mount 15 that will hereinafter be described in more detail.
The castering axis YY for each wheel is preferably positioned in a more forward position of the aircraft compared to the wheel axis X. The castering axis YY preferably does not pass through the wheel axis. In use the castering assembly is configured to set up a positive caster condition when the aircraft is travelling forwards on land.
Whilst in the preferred form a caster assembly as for example shown in
With reference to
Where the landing gear is provided on an amphibious version of the aircraft, each truck 10a and 10b preferably includes or is located in a housing 17 substantially within which each of the wheels is positioned. The housing is provided to help facilitate with the hydrodynamics of the hull form of the amphibious version of the aircraft as a result of the housing presenting itself in a manner to (a) reduce the ingress of water into the housing and (b) reduce contact with the wheels whilst the aircraft is moving on water and (c) provide some of the hull form surface(s) that facilitate hydroplaning for the aircraft.
The housing 17 preferably includes a hard shell 18 and a shroud such as in the form of a compliant membrane 19 that can help, as best as possible, bridge the gap between the hard shell 18 and each respective wheel. The compliant membrane 19 is able to flex and deform as may be necessary when a wheel turns about its respective castering axis, yet remain relatively close if not presses against a respective wheel to help prevent water entering the cavity of the housing. It may not stop water entering at rest but helps prevent water entering when the aircraft is landing at speed and in water.
In the preferred form each wheel projects partially through the mouth opening 20 of the hard shell 18 of the housing 17 and as such the mouth opening is sufficiently sized to accommodate the wheel in its range of rotational caster positions. The hard shell may define one mouth opening for each of the wheels or may provide a plurality of mouth openings one for each of the wheels.
When the wheels are free to caster the compliant membrane may, to some extent, bias the wheel or wheels to a particular rotational position. This may for example be to a position where the wheel or wheels are aligned to the elongate axis of the aircraft. A compliant membrane may act analogous to a spring to bias the wheels to a preferred rotational caster position.
A bridge member 21 may be provided extending between (and preferably articulatable relative to) each of the front and rear landing gear trucks 10a and 10b. Such articulation is for example shown in
Reference will now be made to
The ability for the wheels to so caster improves the safety for aircraft operation. A pilot landing an aircraft in a crab position relative to a runway is able to maintain the crab position during the final approach to the runway, this enables less pilot workload and lowers the risk of loss of control on final approach. The aircraft after touchdown self aligns with the track (runway) meaning that no pilot input is required to correct the aircrafts position prior to touching down, this is especially important as this occurs in close proximity to the ground
Whilst in some forms each of the casterable wheels are independently and individually able to caster, in a more preferred form at least pairings of caster assemblies are coupled. This may help reduce the prospect of caster wobble. By connecting caster assemblies at least in pairs, caster wobble is less likely to occur. In the preferred form more than two caster assemblies are so coupled. Preferably all of the wheels of a landing gear truck are connected for the purposes of reducing the prospect of caster wobble.
With reference to
Upon a touchdown onto a runway by of one of the wheels of a landing gear truck, the arms 23 and link bars 24 will cause castering rotation of that first wheel to touch on the runway to be transferred to the other wheels of the landing gear truck. This means that such other wheels are pre-aligned for touchdown.
Preferably the caster axle 14 passes through the caster assembly mount 15 to present a distal end of the caster wheel axle above the caster wheel mount for and at where the arm 23 is secured.
In the preferred form, as well as being able to caster preferably freely but potentially also within rotational limits, the or each wheel is also able to be controlled for steering the aircraft. The wheel as seen in
To help illustrate the construction of the caster assembly mount 15 reference will now be made to
The caster axle bearings members 26a and 26b are sufficiently spaced from each other to securely hold the caster axle in place and allow for the caster axle to rotate relative thereto about its caster axis YY. The caster axle is preferably also able to move axially relative the bearing members. This allows the wheel to move between an up condition and a down condition that will herein after be further explained.
Securely coupled or forming part of to the caster axle 14 is a steering pin 28. The steering pin preferably extends laterally to the caster axle 14 as can be seen in
The caster axle 14 may also carry a stop 29 that is secured to the caster axle and is provided optionally for the purposes of providing a stop surface to limit the movement of the caster axle in an axial direction relative to the caster axle bearing members 26a and 26b.
A spring 30 may be provided for the purposes of biasing the wheel towards its down condition relative to the caster axle bearing members.
The caster axle may also have attached to it a caster limiting pin 31. Like the steering pin 28 the caster limiting pin may extend laterally through the caster axle 14 and be presented on each side of the caster axle for interaction with caster rotation limiting stops that will hereinafter be described. It is envisaged that the steering may be provided to limit caster.
In the configuration shown in
The caster assembly mount 15 also includes a steering block 33. The steering block 33 is securely connected to a steering arm 34 as seen in
The steering arm 34 is preferably coupled to a steering connection rod 25 as can be seen in
In the preferred form the steering block 33 is mounted in a manner to not travel up and down relative to the caster axle bearing members 26a and 26b. Preferably the steering block is held and prevented for movement, other than for rotation about the caster axis, relative the beam assembly.
As a result of the axial displacement of the caster axle between an up condition as seen in
The caster assembly mount 15 preferably also includes caster angle limiting stops 37. These caster angle limiting stops 37 cooperate with the caster limiting pin 21. Preferably the caster limiting stops are provided as part of the upper caster axle bearing member 26b and are positioned so that they will make contact with the caster limiting pin 31 when the relative rotational angle about the caster axis YY reached a predetermined limit. This may for example be 30 degrees each side of the longitudinal axis of the aircraft.
The caster limiting stops 37 may include rubber blocks so that shock absorption capacity is provided for when the wheels reach the limit of rotation. Limiting the caster angle will help to ensure that the rotational position of the wheel(s) is such that it does require a substantial amount of rotation upon touchdown to align with the aircraft track direction. The height (in the direction of the axis y-y) of the caster angle limiting stops 37 may be such that when the wheel is in the up condition, the caster limiting pin 31 is positioned proud of the caster angle limiting stops. This means that the caster limiting pin is no longer in a position able to engage the stops. This means that when the wheel is in the up condition the wheel is not being limited for rotation by the caster angle limiting stops. Although it could be still limited by that or other limiting stops. However when the wheel is in the down condition the caster limiting pin 31 is able to engage with the caster angle limiting stops.
In
The steering arm may pass through an aperture 38 in the beam 16. The aperture may provide limits of rotation of the arms. The or each end of the steering arm 34 may, by way of a ball and socked connection or other, be connected to a respective steering connection rod.
In one form where there are a plurality of wheels that are able to caster as part of the landing gear of the aircraft, only one of the wheels need to be provisioned for the purposes of steering. It is preferably the front most wheel. Once the aircraft has touched down on land that one wheel can become controlled for steering by the pilot to thereby cause the aircraft to taxi in a controlled manner. However in the preferred form at least two and preferably all of the wheels of the landing gear of the aircraft are able to be controlled for steering. Each of the wheels is preferably hence provisioned with a castering mount as has been described with reference to
Preferably each of the wheels has its steering mechanism coupled by way of steering connection rods that are provided extending between adjacent steering arms of adjacent wheels. The arrangement of steering arms and steering connection rods of adjacent wheels is such that a plurality of wheels will rotate in the same direction as the others.
Where the aircraft includes a front and a rear landing gear truck. A coupling between the sets of wheels of the front landing gear truck and the rear landing gear truck may be such that the rotation of the wheels of the front landing gear truck is opposed to the rotation of the gears of the rear landing wheel truck. This may be achieved by virtue of a steering cable 39 such as is also known as a Morse cable, being appropriately connected to a steering arm of one of the wheels of the front landing gear truck 10a to a steering arm of a wheel of the rear landing gear truck 10b as shown in
The steering cable 39 is preferably able to transfer force between the steering arms and cause opposed rotation of the wheels of the front and rear landing gear trucks.
Such opposed motion, whilst optional, is desirable for when the aircraft is taxing. The opposed motion can improve steering of the aircraft when there are a plurality of wheels provided as it allows for the aircraft to more easily turn left and right. This is for example seen with reference to
Where there are a plurality of wheels of a landing gear truck the steering mechanism is such that each of the wheels preferably turns at a different rate to the other wheels in truck. This is shown in
To achieve such differential steering the connection between the steering arms and the steering connection rods of each wheel is different. With reference to rear landing gear truck 10b of
Where the aircrafts landing gear includes the anti wobble parallelogram mechanism the parallelogram mechanism may require for the link bars 24 to be able to expand and contract in length in order to be compatible with the differential steering mechanics. Otherwise the preferred non-parallelogram configuration of the steering arms and steering connection rods to effect differential steering will fight the anti-wobble parallelogram mechanism. As such the link bars 24 may include an expansion and contraction joint such as a rubber coupling 41 seen in
When airborne the wheels are biased to their down condition. By virtue of gravity and/or the spring 30 each wheel is so biased and are each in the condition are able to caster freely. Such castering preferably being in unison by way of the preferred parallelogram mechanism and limited by rotational stops such a rotational stops 37. The compliant membrane at each of the wheels may also bias the rotational position of the wheels towards one position.
Upon landing the weight of the aircraft starts to bear on the wheels. This biases the wheels towards their up condition. Where the recess 35 of a steering wheel block is aligned with the steering pin the wheel is able to move to its up condition with the steering pin within the recess and allowing steering control over the wheel or wheels to be exercised by the pilot. However where the recess and the steering pin are not aligned the wheels are able to remain independent of the steering mechanism.
Where an aircraft is landing in a cross wind direction such as shown in
With reference to
With reference to
With reference to
An alternative way of causing the aircraft wheels to straighten up the aircraft upon landing and preferably before steering control is able to be exercised over any/all of the wheels is described with reference to
Once the steering pin and recess are engaged and the wheels are in up condition the caster limiting pin 31 moves vertically and sit above compressible stops and therefore not be biased by them towards the centreline position. This means that a pilot taking steering control over the wheels is not having to fight the force that such compressible stops may otherwise apply to the wheels to bias them towards a centreline position. However when the wheels are in their castering condition and not in their steering condition then the rubber pads will apply a force to bias the wheels to a centreline condition. A sloping surface transition may exist between the rotation limiting stops and the compression stops so that when the aircraft has taken off, the wheels can axially drop to their down condition with the caster limiting pin resetting itself for interaction with the compressible stops.
Caster rotation limiting stops 37 are optional. So are the compressible stops.
With reference to
The description so far primarily refers to an aircraft and its landing gear. In the preferred form the aircraft is an amphibious aircraft that is able to land both on land and water. Wheels are described as the mode for moving on land. The wheels can roll over land. Wheeled tracks, such as those found on snow-mobiles are also envisaged as an alternative to wheels to allow rolling contact with the ground.
The aircraft fuselage preferably includes a hull form at the bottom at where the wheels are presented, that is adapted for the purposes of landing on water. Preferably the hull form is both hydrodynamically and aerodynamically formed for travel in water and in air.
The hull includes a recess providing a housing for the wheels to be located. The housing is configured to help facilitate with the hydrodynamics of the hull form of the amphibious version of the aircraft as a result of the housing presenting itself in a manner to (a) reduce the ingress of water into the housing (b) reduce contact between water and the wheels whilst the aircraft is moving on water and (c) provide some of the surface of the aircraft that provides the hydroplaning surface for the aircraft.
Preferably only a small portion of the wheels total height is exposed out of a lower surface 90 of the hull. Shrouding may be provided about the wheels to help prevent water from entering the housing, particularly when landing in water. As described previously the compliant membrane 19 helps achieve this. The compliant membrane 19 may be formed of a neoprene or rubber or other suitable stretchable material that allows the wheels to turn yet still encapsulate the wheel to prevent water ingress. Alternatively a system of nested plates may be provided on lateral sides of the wheels that are able to extend and retract and slide over each other as the wheels turn yet prevent or reduce ingress of water into the housing(s) when travelling through water.
An important safety aspect of this aircraft is that the landing wheels are always positioned for landing on land and in such position is also capable of safely landing on water. The pilot does not need to activate the landing gear between retracted and extended conditions. Preferably each wheel of each truck is housed in a dedicated recesses of the hull form, preferably provided in the lower surface 90 of the hull. The wheels are presented outside the hull in a manner to minimise exposure of the wheels extending below the lower surface yet exposing them sufficiently to allow the aircraft to land on land without the hull form scraping the ground. The wheels preferably remain exposed all the time for landing on land. There is preferably no need for a pilot to deploy or expose the landing wheels for landing on land.
Sponsons 47 may be provided to help offer stability to the aircraft when in water. Sponsons can help provide stability and prevent the aircraft from excessive rolling when in water, especially when sitting idle in water. The sponsons are adapted and configured to help keep the aircraft's wings out of the water.
The aircraft is preferably also equipped with supporting elements 95. These may depend from the wings or from the sponsons. The supporting elements may be arms at the distal ends of which wheels 97 for landing on land and/or hydrodynamic fins or foils for when landing on water may be provided. The foils are preferably adapted and configured to, when travelling through/on water, hydroplane. When at rest the supporting elements may be sufficiently buoyant to help prevent excessive roll of the aircraft in water.
The wheel 97 of each supporting element may act in a similar fashion when landing on land by keeping the wing tips from touching the ground. The wheels 97 may be castered or fixed. Furthermore there may be multiple wheels 97 in line or there are multiple wheels side-by-side, or both.
In a preferred embodiment the supporting elements present both hydroplaning fins and caster wheels. The support elements may comprise a water-ski like member 96 which allows the support elements to plane on the water when landing.
The supporting elements may include suspension which allows the supporting elements to take some shock impact when loading. In a more preferred embodiment the supporting elements are fixed relative to the fuselage.
| Number | Date | Country | Kind |
|---|---|---|---|
| 703670 | Jan 2015 | NZ | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2016/050076 | 1/8/2016 | WO | 00 |
