NZ520769A - Truck streamlining - Google Patents

Abstract

A leading edge aerofoil (7) for reducing drag on a truck (1) carrying or towing at least one bluff body (3,5) is disclosed. The aerofoil has a curved nose with an upper surface angling away from the nose and a lower surface extending rearwardly from the nose. The profile of the aerofoil is such that the vertical distance from the top of the upper surface to the most forward point of the nose is greater than the vertical distance from the forward point of the nose to the lowest point of the lower surface. The aerofoil is configured for attachment to the most forward bluff body of the load (3) or to the top of the tractor unit (1) such that the aerofoil assists in attaching oncoming airflow to the upper surface of the forward bluff body of the load, thereby reducing drag. Further disclosed is a set of aerofoils including the leading edge aerofoil described above, with an additional trailing edge aerofoil (11) on the rearmost bluff body and, if applicable, an intermediate aerofoil (9) configured to direct the airflow between bluff bodies of the load in order to reduce drag.

Description

520 7 69 NEW ZEALAND PATENTS ACT, 1953 NOV 2003 No: 520769 received Date: 26 November 2002 COMPLETE SPECIFICATION TRUCK STREAMLINING We, QUEUE RESEARCH LTD, a New Zealand company of Skeggs House, 60-66 Tennyson Street, Dunedin, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: 2 TRUCK STREAMLINING Field of the Invention This invention relates to aerodynamic devices to assist in reducing drag and streamlining vehicles, and more particularly to assist in reducing drag on trucks having a tractor unit and one or more trailer units. However, the aerodynamic devices are not limited to this use, and may be used to assist in reducing drag on other moving bluff bodies, such as trucks with tray-mounted containers.

Background Rising fuel costs and the need for increased profit margins are two of the reasons why commercial heavy vehicle operators need to address the aerodynamics of their fleet. High 15 bodied vehicles such as trucks having a tractor unit with an "A" train (the trailer immediately behind the tractor unit) and optionally a "B" train (the trailer behind the "A" train), such as curtain-siders or container transporters, present bluff bodies to oncoming air flow. These bluff bodies create significant air drag, and at increased road speeds and distances over which these loads are hauled, an increased proportion of the tractor unit's 20 energy output is expended on overcoming air drag, resulting in increased fuel consumption and associated running costs.

Attempts have been made at addressing this air drag and reducing the associated fuel costs, in the form of deflectors mounted on the top of the tractor unit roof. These deflectors 25 simply deflect the current of moving air up and away from the load attached to the tractor unit, and provide only a limited reduction in air drag and fuel costs. The degree of drag reduction with head on air flow offered by these fittings mounted to the tractor unit varies from 11% for a straight roof-mounted sheet deflector to 30% for a full load height contoured and waisted model. Further, it has been found that some deflectors actually 30 increase the air drag. • 25 3 Another type of known deflector is in the form of a curved body protruding from the front of an "A" train trailer or other bluff body. Again, such a device deflects the air over the top of the trailer, and provides only limited benefits. Typical drag reduction for one of these deflectors is in the order of 5.5%. Further, such a device is generally only used on the front wall of a curtain-sider trailer, and is permanently attached. Due to the permanent attachment, the devices are not generally used with containers.

Both of the above conventional devices simply act as deflectors, and do not address the flow regimes imparted to the vehicle and/or its load when in motion.

It is an object of the present invention to provide aerodynamic devices to assist in reducing drag which address at least one of the abovementioned limitations and/or which at least provides the public with a useful choice.

Summary of the Invention In accordance with a first aspect of the present invention, there is provided a leading edge aerofoil for reducing drag on a truck towing or carrying at least one bluff body as a load, the aerofoil having a curved nose and an upper surface angled away from the curved nose and a lower surface extending rearwardly from the curved nose, with the vertical distance from the lowest point of the lower surface to the most forward part of the curved nose being less than the vertical distance from the upper point of the upper surface to the most forward part of the curved nose, the aerofoil configured for attachment to the most forward bluff body of the load or to the top of a tractor unit with a rear part of the upper surface substantially aligned with an upper surface of the most forward bluff body of the load and with a space provided below the lower surface of the aerofoil, such that the aerofoil assists in attaching oncoming airflow to the upper surface of the most forward bluff body, thereby reducing air drag.

An aerofoil generates lift through a combination of the pressure difference between upper and lower surfaces, and its angle of attack, which is the relative angle of the aerofoil to the oncoming airflow. An aerofoil may have a positive, negative or zero angle of attack.

The aerofoil is preferably configured for attachment to a forward surface of the most forward bluff body. 108227-5 intellectual property office of n2. -9 MAR 2005 RECEIVED 4 The aerofoil is suitably configured to produce lift and laminar flow, thereby assisting in attaching oncoming airflow to the upper surface of the bluff body in use.

Preferably, the aerofoil has a span defined by its width and a chord defined by the distance from the most forward part of the nose to a trailing edge, and the ratio of aerofoil span to aerofoil chord is between about 7:1 and about 9:1.

Preferably, the aerofoil has a chord defined by the distance from the most forward part of 10 the nose to a trailing edge and a maximum thickness defined by the maximum distance between the upper surface and the lower surface, and the ratio of aerofoil chord to maximum aerofoil thickness is between about 1.1:1 and about 1.4:1.

The lower surface is preferably angled away from the curved nose. Preferably, the upper 15 surface generally extends rearwardly from the nose with a greater angle than the lower surface. Preferably, the aerofoil has a maximum thickness defined by the maximum distance between the upper surface and the lower surface, and the vertical distance from the lowest point of the lower surface to the most forward part of the curved nose is between about 22% and 33% of the maximum thickness.

Preferably, the aerofoil has a chord defined by the distance from the most forward part of the nose to a trailing edge and the radius of the nose is about 40% of the aerofoil chord.

The aerofoil suitably includes end plates or fins extending upwardly from respective ends 25 of the aerofoil, which end plates or fins are arranged to assist in entraining air flow over the aerofoil in use. The end plates or fins may extend rearwardly and above an upper rear edge of the aerofoil.

The aerofoil preferably includes attachment means for attaching the device to the most 30 forward bluff body. The attachment means suitably includes flanges configured to engage one or more surfaces of the most forward bluff body.

Alternatively, the attachment means may be configured to engage twist lock or cam lock sockets on a container. The attachment means may include a pair of spaced apart twist lock 35 or cam lock pins configured for receipt in the twist lock or cam lock sockets. Alternatively, 108227-5 intellectual property office of n.z - 9 MAR 2005 RECEIVED the attachment means may include a pair of substantially J-shaped connectors configured for receipt in complementary twist lock or cam lock sockets in the container and configured such that the aerofoil must be tilted to remove it from the container.

In accordance with a second aspect of the present invention, there is provided a set of aerofoils for reducing drag on a truck towing or carrying at least one bluff body as a load, including a leading edge aerofoil as outlined in the first aspect above and a trailing edge aerofoil which is configured for attachment at or adjacent the trailing edge of the most rearward bluff body of the load, and which is configured to reduce the area and volume of 10 the load's turbulent flow in use, thereby reducing air drag.

The trailing edge aerofoil preferably has a central portion with a curved leading edge and a relatively sharp trailing edge.

Preferably, the trailing edge aerofoil has a span defined by its width and a chord defined by the distance from the leading edge of the trailing edge aerofoil to the trailing edge of the trailing edge aerofoil, and the ratio of aerofoil span of the trailing edge aerofoil to aerofoil chord of the trailing edge aerofoil is between about 3.75:1 and about 4.25:1. The ratio of aerofoil span of the trailing edge aerofoil to aerofoil chord of the trailing edge aerofoil may 20 be about 4.1:1.

Preferably, the trailing edge aerofoil has a chord defined by the distance from the leading edge of the trailing edge aerofoil to the trailing edge of the trailing edge aerofoil and a maximum thickness defined by the maximum distance between an upper surface of the 25 trailing edge aerofoil and a lower surface of the trailing edge aerofoil, and the size of the maximum thickness of the trailing edge aerofoil is preferably between about 8.1% and about 13.5% of the size of the chord of the trailing edge aerofoil. The size of the maximum thickness of the trailing edge aerofoil is preferably about 13.2% of the size of the chord of the trailing edge aerofoil.

Preferably, the trailing edge aerofoil has a maximum thickness defined by the maximum distance between the upper surface of the trailing edge aerofoil and the lower surface of the trailing edge aerofoil, and the vertical distance from the lowest point of the lower surface of the trailing edge aerofoil to the forward most portion of the curved leading edge of the 108227-5 intellectual property qfrce of n.z - 9 MAR 2005 RECEIVED 6 0 25 trailing edge aerofoil is between about 35% and 40% of the maximum aerofoil thickness of the trailing edge aerofoil.

Advantageously, the trailing edge aerofoil has a maximum thickness defined by the maximum distance between the upper surface of the trailing edge aerofoil and the lower surface of the trailing edge aerofoil, and the radius of the curved leading edge of the trailing edge aerofoil is between about 30% and about 35% of the maximum thickness of the trailing edge aerofoil. The radius of the curved leading edge of the trailing edge aerofoil may be about 33.3% of the maximum thickness of the trailing edge aerofoil.

The trailing edge aerofoil preferably includes at least one vortex generating projection to induce a rearward vortex in use. More preferably, the trailing edge aerofoil includes a pair of vortex generating tips at the ends of the aerofoil.

Preferably the tips of the trailing edge aerofoil extend rearwardly, and are arranged so that in use two vortices of opposite sense are generated, confining drag to a smaller area. The tips of the trailing edge aerofoil may be arranged so that in use, as the vortices travel rearwardly they enlarge in diameter and impinge on each other, pulling turbulent air stream which is exiting from the underside of the vehicle into a substantially constant flow regime. The tips of the trailing edge aerofoil preferably extend upwardly when the trailing edge aerofoil is attached to the bluff body.

Preferably, the trailing edge aerofoil has a chord defined by the distance from a leading edge of the trailing edge aerofoil to a trailing edge of the trailing edge aerofoil, and the tips extend rearwardly of the trailing edge of the trailing edge aerofoil by about 25% of the chord of the trailing edge aerofoil.

Preferably, the trailing edge aerofoil has a maximum thickness defined by the maximum distance between an upper surface of the trailing edge aerofoil and a lower surface of the trailing edge aerofoil, and the rise of each tip directly above the point of maximum thickness of the trailing edge aerofoil is about 14% of the maximum thickness of the trailing edge aerofoil.

In a preferred embodiment, the trailing edge aerofoil is configured for attachment to the most rearward bluff body so that its point of maximum lift is located substantially directly 108227-5 INTELLECTUAL PROPERTY office OF M7. 9 ¥M 2005 RECEIVE 7 above the trailing edge of the bluff body, and so that a gap is provided between the lower surface of the trailing edge aerofoil and the trailing edge of the bluff body.

The trailing edge aerofoil is preferably configured for attachment at or adjacent the trailing 5 edge of the most rearward bluff body of the load with a positive angle of attack relative to oncoming airflow, to downwardly direct oncoming airflow.

The trailing edge aerofoil suitably includes attachment means for attaching the trailing edge aerofoil at or adjacent the trailing edge of the most rearward bluff body of the load. The 10 attachment means for attaching the trailing edge aerofoil may include flanges configured to engage one or more surfaces of the most rearward bluff body.

Alternatively, the attachment means for attaching the trailing edge aerofoil may be configured to engage twist lock or cam lock sockets on a container. The attachment means 15 for attaching the trailing edge aerofoil advantageously includes a pair of spaced apart twist lock or cam lock pins configured for receipt in the twist lock or cam lock sockets. Alternatively, the attachment means for attaching the trailing edge aerofoil may include a pair of substantially J-shaped connectors configured for receipt in complementary twist lock or cam lock sockets in the container and configured such that the aerofoil must be 20 tilted to remove it from the container.

In accordance with a third aspect of the present invention, there is provided a set of aerofoils as outlined in the second aspect above for reducing drag on a truck towing or carrying at least two bluff bodies as a load, including an intermediate aerofoil which is 25 configured for attachment at or adjacent the upper trailing edge of the most forward of the bluff bodies of the load, and which is configured in use to direct airflow over the gap between the most forward bluff body and a following bluff body and toward the upper surface of the following bluff body in use, thereby reducing air drag.

The intermediate aerofoil may have a central portion with a curved leading edge and a relatively sharp trailing edge.

Preferably, the intermediate aerofoil has a span defined by its width and a chord defined by the distance from the leading edge of the intermediate aerofoil and the trailing edge of the 35 intermediate aerofoil, and the ratio of aerofoil span of the intermediate aerofoil to aerofoil 108227-5 intellectual property ofice of n.h -9 MAR 2005 RECEIVED 8 chord of the intermediate aerofoil is between about 5.5:1 and about 6:1. The ratio of aerofoil span of the intermediate aerofoil to aerofoil chord of the intermediate aerofoil may be about 5.8:1.

Preferably, the intermediate aerofoil has a chord defined by the distance from the leading edge of the intermediate aerofoil to the trailing edge of the intermediate aerofoil and a maximum thickness defined by the maximum distance between an upper surface of the intermediate aerofoil and a lower surface of the intermediate aerofoil, and the size of the maximum thickness of the intermediate aerofoil is between about 8.1% and 13.5% of the 10 size of the chord of the intermediate aerofoil. The size of the maximum thickness of the intermediate aerofoil is preferably about 13% of the size of the chord of the intermediate aerofoil.

In a preferred embodiment, the intermediate aerofoil has a maximum thickness defined by 15 the maximum distance between the upper surface of the intermediate aerofoil and the lower surface of the intermediate aerofoil, and the vertical distance from the lowest point of the lower surface of the intermediate aerofoil to the forward most portion of the curved leading edge of the intermediate aerofoil is between about 35% and 60% of the maximum aerofoil thickness of the intermediate aerofoil. The vertical distance from the lowest point of the 20 lower surface of the intermediate aerofoil to the forward most portion of the curved leading edge of the intermediate aerofoil may be about 58% of the chord of the intermediate aerofoil.

Preferably, the intermediate aerofoil has a maximum thickness defined by the maximum 25 distance between the upper surface of the intermediate aerofoil and the lower surface of the intermediate aerofoil, and the radius of the curved leading edge of the intermediate aerofoil is between about 15% and about 20% of the maximum thickness of the intermediate aerofoil. The radius of the curved leading edge of the intermediate aerofoil may be about 17% of the maximum thickness of the intermediate aerofoil.

The intermediate aerofoil preferably includes a pair of upwardly extending members or projections at respective ends to assist in entraining airflow over the surface of the central portion of the intermediate aerofoil. 108227-5 intellectual property office of n.z -9 MAR 2005 RECEIVED 9 Preferably, the intermediate aerofoil has a maximum thickness defined by the maximum distance between an upper surface of the intermediate aerofoil and a lower surface of the intermediate aerofoil, and the members or projections extend above the trailing edge of the intermediate aerofoil by about the maximum thickness of the intermediate aerofoil.

Preferably, the intermediate aerofoil has a chord defined by the distance from the leading edge of the intermediate aerofoil to the trailing edge of the intermediate aerofoil, and wherein the members or projections extend forwardly of the leading edge of the intermediate aerofoil by about 5% of the chord of the intermediate aerofoil.

Preferably, the intermediate aerofoil has a maximum thickness defined by the maximum distance between an upper surface of the intermediate aerofoil and a lower surface of the intermediate aerofoil, and the intermediate aerofoil is configured for attachment to the most forward bluff body so that its point of maximum thickness is located substantially directly 15 above the trailing edge of the bluff body, and so that a gap is provided between the lower surface of the intermediate aerofoil and the trailing edge of the bluff body.

In a preferred embodiment, the intermediate aerofoil has a central portion with a curved leading edge and a relatively sharp trailing edge, and the intermediate aerofoil is configured 20 for attachment at or adjacent the trailing edge of the most forward of the bluff bodies of the load with a positive angle of attack relative to oncoming airflow, to downwardly direct oncoming airflow. The angle of attack of the central portion of the intermediate aerofoil may be about 2 degrees.

The intermediate aerofoil preferably includes attachment means for attaching the intermediate aerofoil at or adjacent the trailing edge of the most forward bluff body of the load. The attachment means for attaching the intermediate aerofoil may include flanges configured to engage one or more surfaces of the most forward of the bluff bodies.

Alternatively, the attachment means for attaching the intermediate aerofoil may be configured to engage twist lock or cam lock sockets on a container. Preferably, the attachment means for attaching the intermediate aerofoil includes a pair of spaced apart twist lock or cam lock pins configured for receipt in the twist lock or cam lock sockets. Alternatively, the attachment means for attaching the intermediate aerofoil may include a 35 pair of substantially J-shaped connectors configured for receipt in complementary twist lock or cam lock sockets in the container and configured such that the aerofoil must be tilted to remove it from the container. 108227-7 'RLEClUALppROpERTy OFHCE 2 S APR 2005 Mcejved In accordance with a fourth aspect of the present invention, there is provided a leading edge aerofoil as outlined in the first aspect above, when attached to the most forward bluff body of a load being towed or carried by a truck, or when attached to the top of the tractor unit, 5 such that a rear part of the upper surface is substantially aligned with an upper surface of the most forward bluff body and a space is provided below the lower surface of the aerofoil.

In accordance with a fifth aspect of the present invention, there is provided a set of 10 aerofoils as outlined in the second aspect above, when the leading edge aerofoil is attached to the most forward bluff body of a load being towed or carried by a truck, or when attached to the top of the tractor unit, such that a rear part of the upper surface is substantially aligned with an upper surface of the most forward bluff body and a space is provided below the lower surface of the aerofoil, and when the trailing edge aerofoil is 15 attached at or adjacent the trailing edge of the most rearward bluff body of the load being towed or carried by a truck.

In accordance with a sixth aspect of the present invention, there is provided a set of aerofoils as outlined in the third aspect above, when the leading edge aerofoil is attached to 20 the most forward bluff body of a load being towed or carried by a truck, or when attached to the top of the tractor unit, such that a rear part of the upper surface is substantially aligned with an upper surface of the most forward bluff body and a space is provided below the lower surface of the aerofoil, and when the trailing edge aerofoil is attached at or adjacent the trailing edge of the most rearward bluff body of the load being towed or 25 carried by a truck, and when the intermediate aerofoil is attached at or adjacent the trailing edge of the most forward bluff body of the load being towed or carried by a truck.

In accordance with a seventh aspect of the present invention, there is provided a truck towing or carrying at least one bluff body as a load, including a leading edge aerofoil as 30 outlined in the first aspect above attached to the most forward bluff body of the load or to the top of a tractor unit, with the upper surface of the aerofoil substantially aligned with an upper surface of the most forward bluff body of the load and a space provided below the lower surface of the aerofoil, to assist in attaching oncoming airflow to the upper surface of the most forward bluff body, thereby reducing air drag. 108227-5 intellectual property office of n.z -9 MAR 2005 RECEIVED 11 In accordance with an eighth aspect of the present invention, there is provided a truck towing or carrying at least one bluff body as a load, including a set of aerofoils as outlined in the second aspect above, with the leading edge aerofoil attached to the most forward bluff body of the load or to the top of a tractor unit, with the upper surface of the aerofoil substantially aligned with an upper surface of the most forward bluff body of the load and a space provided below the lower surface of the aerofoil, to assist in attaching oncoming airflow to the upper surface of the most forward bluff body, and with the trailing edge aerofoil attached at or adjacent the trailing edge of the most rearward bluff body of the load, to reduce the area and volume of the load's turbulent flow, thereby reducing air drag.

In accordance with a ninth aspect of the present invention, there is provided a truck towing or carrying at least two bluff bodies as a load, including a set of aerofoils as outlined in the third aspect above, with the leading edge aerofoil attached to the most forward bluff body of the load or to the top of a tractor unit, with the upper surface of the aerofoil substantially 15 aligned with an upper surface of the most forward bluff body of the load and a space provided below the lower surface of the aerofoil, to assist in attaching oncoming airflow to the upper surface of the most forward bluff body, and with the trailing edge aerofoil attached at or adjacent the trailing edge of the most rearward bluff body of the load, to reduce the area and volume of the load's turbulent flow, and with the intermediate aerofoil 20 attached at or adjacent the upper trailing edge of the most forward of the bluff bodies of the load and configured to direct airflow over the gap between the most forward bluff body and the following bluff body and toward the upper surface of the following bluff body, thereby reducing air drag.

Preferably, the truck comprises a tractor unit and "A" and "B" train trailers, and the intermediate aerofoil is attached to the upper trailing edge of the "A" train trailer. The trailers may be curtain-sider trailers for example, or the aerofoil could be attachable to a container.

Preferably, the truck comprises a tractor unit and "A" and "B" train trailers, and the leading edge aerofoil is attached to the upper trailing edge of the "A" train trailer. The trailers may be curtain-sider trailers for example, or the aerofoil could be attachable to a container. 108227-5 Intellectual PHWtH iv uh-ice OF N.Z - 9 MAR 2005 RECEIVED 12 The set of aerofoils of the second or third aspect above may include attachment means for attaching the aerofoil(s) to the bluff body or bodies and configured such that the aerofoil(s) can be interchanged between one bluff body and another.

In accordance with a tenth aspect of the present invention, there is provided a method of streamlining a truck carrying or towing one or more bluff bodies, including fitting a leading edge aerofoil as outlined in the first aspect above to the most forward bluff body or tractor unit, or a set of aerofoils as outlined in the second or third aspect above to one or more bluff bodies.

In one embodiment, the truck is loaded to tow or carry only a single bluff body and the method includes fitting a leading edge aerofoil as outlined in the first aspect above to the most forward bluff body or tractor unit such that the rear part of the upper surface of the aerofoil is substantially aligned with the upper surface of the most forward bluff body with 15 a space provided below the lower surface of the aerofoil, and fitting a trailing edge aerofoil of the set as outlined in the second or third aspect above at or adjacent the upper trailing edge of the bluff body.

In an alternative embodiment, the truck is loaded to tow or carry two bluff bodies and the 20 method includes fitting a device as outlined in the first aspect above to the most forward bluff body or tractor unit such that the rear part of the upper surface of the aerofoil is substantially aligned with the upper surface of the most forward bluff body and a space is provided below the lower surface of the aerofoil, fitting an intermediate aerofoil of the set as outlined in the third aspect above at or adjacent the upper trailing edge of the most 25 forward bluff body, and fitting a trailing edge aerofoil of the set as claimed in the second or third aspect above at or adjacent the upper trailing edge of the most rearward bluff body.

The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

Brief Description of the Drawings Preferred embodiments of the present invention will be described by way of example only with reference to the accompanying figures in which: I'mEllECTUAlPBUPtH.f ufflCE -9 MAR 2005 RECEIVED 13 Figure 1 is a schematic side elevation view of a tractor unit and "A" and "B" train trailers, indicating the primary areas contributing to overall drag; Figure 2 is a schematic side elevation view of the tractor unit and "A" and "B" train trailers, indicating high pressure regions; Figure 3 is a schematic plan view of the tractor unit and "A" and "B" train trailers of Figure 1 when turning, or when the wind approaches the vehicle from a similar angle; Figure 4 shows a schematic side elevation view of the tractor unit and "A" and "B" train trailers fitted with aerofoils in accordance with a preferred embodiment of the present invention; Figure 5a schematically shows the relative shape of a prior art leading edge deflector mounted on the front of an "A" train; Figure 5b schematically shows the relative shape of a preferred embodiment leading edge aerofoil removably attached to an "A" train; Figure 6a shows a schematic side elevation view of a trailing edge aerofoil mounted on a 15 "B" train Mid the resulting airflow; Figures 6b and 6c show schematic plan and rear views respectively of a preferred trailing edge aerofoil; Figure 7a is a schematic side elevation view of the trailing edge drag cone for a tractor unit and "A" and "B" train trailers without aerofoils; Figure 7b is a schematic side elevation view showing turbulent flow caused by a tractor unit and "A" and "B" train trailers with a tractor-mounted deflector only; Figure 7c is a schematic side elevation view of the trailing edge drag cone for a tractor unit and "A" and "B" train trailers with preferred embodiment aerofoils attached; Figure 8a is a schematic side elevation view of the airflow over and behind a tractor unit 25 (not shown) and "A" and "B" train trailers without aerofoils; Figure 8b is a schematic side elevation view of the airflow over and behind a tractor unit (not shown) and "A" and "B" train trailers fitted with preferred embodiment aerofoils; Figure 8c is a rear view of a rearmost bluff body showing the deposition pattern of road film which results from the use of the preferred embodiment aerofoils; Figure 9 is a front view of the outer mould for forming the curved portion of a preferred embodiment leading edge stubnose aerofoil; Figure 10 is a forward view of the mould of Figure 9, showing its curvature; Figure 1 la is a front overhead perspective view of the preferred stubnose aerofoil showing an end plate; Figure 1 lb is a schematic side view or the aerofoil of Figure 11a; 108227-5 intellectual property office of n.z -9 MAR 2005 RECEIVED 14 • 25 Figure 12 is a schematic perspective view showing the aerofoil of Figures 9 to 1 lb attached to the leading edge of the forward bluff body; Figure 13 is a sectional view through the central part of the aerofoil of Figures 9 to 12, showing its curvature and shape; Figure 14 is a left side elevation view of a mould of the central part of a preferred embodiment intermediate aerofoil for directing air over the train gap; Figure 15 is a view of an inner side of an end plate mould for the aerofoil of Figure 12; Figure 16 is a side view of a face plate mould for attachment to the outer side of an end plate such as shown in Figure 15, with an end plate attached; Figure 17 is a sectional view through the central part of the aerofoil of Figures 14 to 16, showing its shape and curvature; Figure 18 is a front view of a preferred embodiment trailing edge aerofoil; Figure 19 is a front perspective view of one side of the aerofoil of Figure 18, showing one of the Horner tips; Figure 20 is a rear perspective view of the opposite side of the aerofoil of Figure 18, showing the other Horner tip; Figure 21 is a front sectional view of the aerofoil of Figures 18 to 20, showing the interconnection of the tips to the central part; Figure 22 is a sectional view through the central part of the aerofoil of Figures 18 to 21, showing its shape and curvature; Figure 23 shows a pair of support members being used to support the aerofoil of Figures 18 to 22 on a bluff body; Figure 24 schematically shows an aerofoil supported on a bluff body by the support members of Figure 23; Figure 25 schematically shows the interconnection of an aerofoil to a twist lock socket on a container using a twist lock pin; and Figure 26 schematically shows an alternative interconnection of the aerofoil to a twist lock socket on a container.

Detailed Description of Preferred Forms Wind tunnel testing shows typical bluff bodied vehicles to have a drag coefficient within the range of 0.8-1.3. Joined vehicles such as tractor and trailer units increase these typical figures. 108227-5 intellectualpproperty office -9 MAR 2005 RECEIVED The energy necessary to overcome tractive resistance for a moving truck can be conveniently divided into three areas; rolling resistance, acceleration (and climbing resistance), and air drag. At higher speeds, the proportion of tractive resistance expended on air drag becomes greater. As an example, a high bodied tractor unit/trailer combination 5 weighing 38 tonnes requires 25 kW of power to overcome the air drag it generates at 60 km/hr. At higher speeds such as 100 km/hr, the energy required to overcome air drag increases to 70-75 kW. This energy is necessarily provided by the tractor unit and comes at the cost of increased fuel consumption.

The percentages of tractive resistance at highway speeds of 100 km/hr for a tractor unit towing "A" and "B" train trailers can be divided into the following: • Rolling resistance approximately 52% • Acceleration and climbing resistance approximately 30% 15 • Air drag approximately 18% Typical fuel consumption to overcome the resistance to air drag on level roads at 72 km/hr is 35% of the total fuel used. This figure increases with road speed and may approach 38-40% at road speeds of 100-110 km/hr.

Airflow and its principal drag interactions over a tractor unit and its load can be seen as "formations" made up of the various sub-bodies which interact with each other. When the relative airflow is coming from directly in front of the truck, the partial drag of the entire body composed of the tractor unit and two trains following it can be divided up into the 25 ratio of 4:3:2. When the gaps between the tractor unit and the "A" train, and/or between the "A" train and the "B" train increase, a slight increase in drag is observed.

When traveling in a straight line such that the relative airflow approaches the tractor unit and trailer(s) from directly in front of the tractor unit, the areas which contribute to the 30 overall drag are the roof of the tractor unit; the front edge, upper face and lip of the "A" train; the aft upper edge of the "A" train, the forward facing upper edge and panel of the "B" train, and the rearmost edge and rear (vertical) panel of the "B" train, as indicated schematically by the arrows D in Figure 1, in which reference numeral 1 represents the cab 108227-5 intellectual property office of n.z - 9 MAR 2005 RECEIVED 16 or tractor unit, 3 is the "A" train, and 5 is the "B" train. The spirals represent turbulent flow. The hatched areas in Figure 2 indicate the high pressure regions around the tractor unit and "A" and "B" trains.

When turning or when driving in strong side winds such that the relative airflow approaches the vehicle from an angle, the drag coefficient of both of the "A" and "B" trains increases significantly, increasing the overall drag of the vehicle. This effect is principally due to the front panel of a container or curtain-sider trailer opening the gap between the tractor unit and the load train (and the gap between the "A" and "B" train if a "B" train is 10 being towed). The opposing, or lee side, of the load also acts aerodynamically as the rear side of the vehicle relative to the airflow, and turbulent flow occurs in this area increasing drag as a result. This is indicated schematically in Figure 3, in which arrow AW indicates the direction of the apparent wind or relative airflow due to the forward motion and turning of the tractor unit 1.

When the relative airflow is approaching from an angle due to the truck turning (ie operating in yaw), the tractor unit does not experience leeward separation flow as it is turning into the airflow. The tractor unit operates in positive pressure regimes irrespective of its angle to the apparent wind.

In accordance with a preferred embodiment of the present invention, a number of aerofoils are attached to the "A" and "B" train in order to minimise drag. With reference to Figure 4, three such aerofoils are shown. A leading edge aerofoil 7 is attached to the upper front edge of the "A" train 3, an intermediate aerofoil 9 is attached to the upper rearward edge of 25 the "A" train, and a trailing edge aerofoil 11 is attached to the upper rearward edge of the "B" train 5. It should be appreciated that the aerofoils are not shown to scale in this Figure. A deflector plate may or may not be attached to the roof of the tractor unit 1 to direct oncoming airflow to the leading edge aerofoil 7, however such a deflector is not essential. 17 Figure 5 a shows the shape of a typical prior art leading edge curved deflector 101. It can be seen that the upper surface of the deflector 101 is relatively steep, which causes the approaching airflow A to be deflected away from the upper surface of the "A" train. The preferred leading edge aerofoil 7 shown schematically in Figure 5b is attached to the high 5 pressure region of the "A" train. Rather than deflecting the approaching airflow A away from the upper surface of the "A" train, it can be seen that the preferred leading edge aerofoil 7 assists in attaching the airflow to the upper surface of the "A" train.

Although only shown schematically in this Figure, it can be seen that the shape of the 10 aerofoil 7 is different to that of deflector 101. In particular, the leading edge aerofoil is actually a stubnose part-aerofoil (in that it has a curved leading edge, but does not terminate at a rearward tapered part), and can be seen to have a greater chord, and a less steep upper surface than the prior art deflector. The lower surface is also less steep than the lower surface of the prior art deflector. The aerofoil has a curved nose and an upper surface 15 angled away from the nose, and is preferably attached to the bluff body so that a rear part of the upper surface is substantially aligned with the upper surface of the bluff body. An alternative is that the aerofoil could be attached to the tractor unit with the rear part of the upper leading surface substantially aligned with the upper surface of the bluff body.

Factors which may contribute to performance include the curvature, stagnation point, length in relation to the bluff body (in this case the "A" train), aspect ratio, chord thickness ratio, and end plate design. At least some of these features, which are described in more detail below with reference to Figures 12 and 13, determine the form and reduced drag, as well as the resulting airflow behind the aerofoil and the flow regimes in relation to the bluff 25 body. The aerofoil 7 produces lift and laminar flow, allowing the rearward flow to be nearer to the bluff body surface.

Reverting to Figure 4, the intermediate aerofoil 9 is arranged to reduce the drag gap between the "A" and "B" train by "grabbing" the air traveling along the upper surface of 30 the "A" train and reducing the wake area. The aerofoil 9 is arranged at a shallow positive 18 angle of attack to the oncoming airflow from the upper surface of the "A" train, such as about 2 degrees. A positive angle of attack is one in which the leading edge of the aerofoil is spaced a greater distance above the upper surface of the bluff body than the trailing edge. The angle of the aerofoil is measured between the datum of the aerofoil and the upper 5 surface of the bluff body. The aerofoil is preferably semi-symmetrical and positioned so that the point of maximum lift (or camber), which in this embodiment is approximately 30% of the chord, is located directly above the sharp trailing edge of the "A" train. This aerofoil acts to increase the speed of the airflow across the "A" and "B" train gap, and direct the airflow from the upper surface of the aerofoil 9 toward the flat upper surface of 10 the "B" train, negating or minimising the high pressure area which would normally exist. The angle of attack of the intermediate aerofoil 9 may be variable to change the properties of the airflow if desired.

The trailing edge aerofoil 11 may be mounted on the "B" train with a slightly more positive 15 angle of attack (in other words, the datum of the aerofoil is slightly more steep) than the intermediate aerofoil 9 is mounted on the "A" train, to direct downwash so that the degree of turbulence and large area of drag normally associated with the rear of the bluff body is "boat-tailed", reducing its area. The airflow behind the rear of the "B" train meets and mixes with the turbulent airflow from under the vehicle, further reducing drag, as indicated 20 schematically in Figure 6a.

A gap is suitably provided between the lower surface of each of the aerofoils and the respective bluff bodies.

The trailing edge aerofoil 11 includes a central aerofoil portion 13 and end plates 15 (only one of which is visible) forming Horner tips which generate a rearward vortex from each side of the aerofoil. The point of maximum thickness of the trailing edge aerofoil is preferably located directly above the rear surface of the "B" train. When viewed from the rear of the "B" train, the left vortex spirals in a clockwise direction, and the right vortex 30 spirals in an anticlockwise direction. The result of these vortices is that most of the drag is 19 confined to a smaller area than it would be without the trailing edge aerofoil 11. As the vortices travel rearwardly, they enlarge in diameter and impinge on each other, pulling the turbulent airstream which is exiting from the rear underside of the vehicle into a constant flow regime, and sweeping and rolling the airstreams together. The effect is that the area 5 and volume of the vehicle's turbulent flow is reduced, thereby reducing drag.

The relative sizes of the rearward drag cones (shown as hatched areas) from the vehicles with and without the trailing edge aerofoils can be seen from Figure 7, and it will be noted that the drag cone for the vehicle with the trailing edge aerofoil is significantly smaller than 10 that for the vehicle without a trailing edge aerofoil.

Again, if desired, the angle of attack of the trailing edge aerofoil may be adjustable.

Preferred embodiment leading edge, intermediate, and trailing edge aerofoils are shown in 15 Figures 9-13, 14-17 and 18-22 respectively. It will be noted from the Figure descriptions that a number of the Figures show moulds. These moulds are generally covered by a suitable material such as glass fibre reinforced composite to form the final components. It should be noted that Figures 13, 17 and 22 show the aerofoils the correct way up, i.e. in the orientations in which they would be attached in use.

Figures 9 and 10 show a mould of the central portion of the leading edge stubnose aerofoil shown in Figure 11, showing the curvature of the surface. The leading edge stubnose part-aerofoil 7 includes a central portion 21 having a curved leading surface 23. As shown in Figure 11, end plates 29, 31 are attached to each end of the central portion 21. As shown, 25 these endplates form upwardly-extending fins to entrain airflow over the surface of the aerofoil in use. As can be seen from Figure 11a and Figure lib, which shows a cross section of one end of the aerofoil, the fins may start at the Phillips entry point or most forward curved part of the aerofoil. Alternatively, the fins may extend around the underside of the aerofoil. Also, as shown schematically in Figure 1 lb, mounting flanges F are provided, one to attach the aerofoil to the upper surface of the bluff body, the other to attach the aerofoil to the forward surface of the bluff body.

It should be noted that the ratio of the Phillips entry, that being the vertical distance 5 between the lower surface of the aerofoil and the Phillips entry point (or stagnation point) vs the distance between the upper surface of the aerofoil and the Phillips entry point (or stagnation point) is selected to obtain optimum aerodynamic properties.

Figure 12 schematically shows the preferred embodiment front aerofoil mounted on a bluff 10 body, and Figure 13 shows a cross sectional view of the central portion of the aerofoil. It can be seen that the aerofoil is a part section aerofoil. The preferred aerofoil has a span S (measured between the insides of the end plates) to chord C ratio (known as the aspect ratio) of between about 7:1 and 9:1, and a chord C to thickness T ratio of between about 1.1:1 and 1.4:1. The height SPH of the stagnation point SP is generally between about 22% 15 and 33% of the thickness T. The radius of the nose (in the vicinity of the stagnation point SP) of the aerofoil is preferably about 40% of the chord C of the aerofoil. The upper forward surface above the stagnation point SP preferably has a smooth surface finish, with a maximum surface roughness of about 1 mm. It can be seen that the lower surface has a generally flatter profile than the upper surface. These parameters, and the relatively bluff 20 body below the aerofoil, induce a stagnant flow below the aerofoil, and induce laminar flow over the aerofoil. The laminar flow entrains air and pulls it down towards the upper surface of the bluff body. The vertical end plates "fence" the airflow at the extreme ends of the aerofoil, which reduces turbulence. Without the plates, there would normally be turbulence at the tip section of the aerofoil. The aerofoil reduces drag caused by the leading edge of 25 the bluff body, which can amount to 25% of the total vehicle drag.

The aerofoil is preferably mounted on the bluff body with an approximately zero degree angle of attack to the oncoming airflow. However, due to the low position of the stagnation point, and the greater curvature and distance over the upper surface than the lower surface, 21 the aerofoil effectively has an upward or positive angle of attack to the oncoming air (i.e. is equivalent to an aerofoil having its nose higher than its trailing edge).

As mentioned above, the aerofoil preferably includes end plates 29, 31 which form 5 aerodynamic fins or fences to entrain airflow. The end plate fins extend above the trailing edge of the aerofoil as shown in Figure 12. In the embodiment in which the aerofoils are provided as a set, it is preferred that the fins extend above the trailing edge of the leading edge aerofoil by about the maximum thickness of the intermediate aerofoil described below. The end plates project forwardly of the aerofoil and above the leading 10 edge/stagnation point SP by about 5 % of the chord of the aerofoil. The end plates preferably include mounting flanges so that they act as stands to support the aerofoil on the bluff body.

As shown in Figure 14, the intermediate aerofoil 9 includes a central portion 41 having a 15 curved leading surface and a relatively sharp trailing edge. The aerofoil also includes end plates 43, 45 one of which is shown in Figure 15. The right end plate 45 shown in the Figures would be located on the right side of the vehicle when the intermediate aerofoil 9 is mounted on the rear of the "A" train, and a left end plate would be located on the left side of the vehicle. The end plate 45 has a lower flange 49 having a base portion 51 which rests 20 against the upper surface of the "A" train when the aerofoil is installed, and a rear portion 53 which locates against the back wall of the "A" train when installed. A socket 47 is provided on the inside of each end plate for receipt of a respective end of the central portion 41 of the aerofoil 9. Although not shown in these figures, the intermediate aerofoil could be mounted such that its angle of attack is variable.

As shown in Figure 16, a face plate 55 is attached to the outer surface of the end plate 43. The face plate 55 has an upper vertical plate section, which extends above the aerofoil central portion 41 when attached to the end plate 43. The purpose of the upper vertical plate section is to direct airflow over the central portion 41 of the aerofoil. The face plate 30 55 is a manufacturing convenience, and the upper vertical plate sections could be provided INTELLECTUAL PROPERTY QFhCE OF 108227-7 2 6 APR 2035 .RECEIVED 22 as part of the end plates 43, 45 if desired, or could be unitary with the aerofoil central portion.

The curvature of the central portion of the preferred intermediate aerofoil is shown in 5 Figure 17. The preferred aspect ratio (span to chord ratio) is between about 5.5:1 and about 6:1, and more preferably about 5.8:1. The size of the maximum thickness T is preferably between about 8.1% and 13.5% of the size of the chord. More preferably, the size of the maximum thickness T is preferably about 13% of the size of the chord. The point of maximum camber MC (camber being a median line between the upper surface and lower 10 surface) is preferably between about 30 and 35% of the chord, and more preferably about 32.8% of the chord, measured from the front of the aerofoil. The stagnation point height SPH is preferably between about 35% and about 60% of the thickness T measured from the base, and more preferably about 58% of the thickness T. The nose radius is preferably between about 15% and about 20% of the thickness T, and more preferably about 17% of 15 the thickness T.

As mentioned above, the aerofoil preferably includes face plates and end plates which form aerodynamic fins or fences to entrain airflow. The fins extend above the trailing edge of the aerofoil, preferably by about the maximum thickness T of the aerofoil. The plates 20 project forwardly of the aerofoil and above the leading edge/stagnation point SP by about 5 % of the chord of the aerofoil. The plates preferably include mounting flanges so that they act as stands to support the aerofoil on the bluff body.

As shown in Figures 18-22, the trailing edge aerofoil 11 includes a central portion 13 and a 25 pair of rearwardly-extending vortex generating Horner tips 15, 16. The central portion has a curved front edge 61 and a relatively sharp rear edge 63. It can be seen that the aerofoil is of relatively low cross-sectional profile. The purpose of the vortex generating end tips and the aerofoil has been described above. 23 The curvature of the central portion of the preferred trailing edge aerofoil is shown in Figure 22. The preferred aspect ratio (span to chord ratio) is between about 3.75:1 and about 4.25:1, and more preferably about 4.1:1. The size of the maximum thickness T is preferably between about 8.1% and 13.5% of the size of the chord. More preferably, the 5 size of the maximum thickness T is preferably about 13.2% of the size of the chord. The point of maximum camber MC is between about 37.5% and 42.5% of the chord, and more preferably about 39.5% of the chord (measured from the front of the aerofoil). The stagnation point height SPH is preferably between about 35% and about 40% of the thickness T measured from the base, and more preferably about 36% of the thickness T. 10 The nose radius is preferably between about 30% and about 35% of the thickness T, and more preferably about 33.3% of the maximum thickness T.

The Horner tips 15, 16 preferably extend behind the trailing edge of the aerofoil by about 25% of its chord. The rise of each tip 15, 16 directly above the point of maximum 15 thickness is preferably about 14% of the maximum thickness.

One form of support members 71, 73 for mounting the aerofoil 11 on the trailing edge of a "B" train are shown in Figures 23 and 24. With reference to the left support member 71 shown in the Figures, the support member 71 includes a mounting part 75 for mounting the 20 support member 71 on the rear left corner of the "B" train, and a shaped upper sxirface or saddle 77 upon which the aerofoil 11 is mounted. As shown in Figure 24, the mounting part 75 includes an upper flange 105, a rear flange 101 and a side flange 103. When attached to the "B" train, these flanges will be located against respective surfaces of the "B" train. In a preferred embodiment, the support members 71, 73 may be provided integrally 25 with the aerofoil 11. Although not shown in the figures, if desired the trailing edge aerofoil 11 may be mounted so that its angle of attack is adjustable.

All of the aerofoils may be provided in two or more pieces so that they may be easily sized as necessary to incorporate bluff bodies of differing widths. In particular, the aerofoils may 30 be provided as an elongate piece including for example a fitting, end plate, and the full 24 aerofoil blade, and a cap piece including for example a fitting and end plate. The elongate piece can then be cut to the required length to accommodate the width of the particular bluff body, and then inserted into a socket on the cap end. In the case of the trailing edge aerofoil 11, this could be provided with the cap end having a support member and one of 5 the Horner tips.

As shown schematically in Figure 21 for example, the trailing edge aerofoil has seams 64 defined by sockets separating the end portions (and fins) from the central portion. This enables the central portion to be cut to length, and slotted in to the end portions to suit 10 trucks of various widths.

The aerofoils may be semi-permanently or permanently attached to the bluff bodies for example with fasteners such as bolts, rivets, adhesives, etc (or combinations of the above), or more preferably are detachably attached to the bluff bodies so that they can easily be 15 attached to different loads. For example, the aerofoils may be attachable to trailers or containers through the use of cam lock or twist lock type mechanisms. Preferably, a pair of spaced apart cam lock or twist lock pins or lugs extend downwardly from the aerofoils, and are receivable in complementary generally oblong cam lock or twist lock sockets at the corners of containers. Standard containers have such twist lock sockets, which are 20 conventionally used to fasten the container to one placed on top of it. If necessary, tie-down straps may be used to provide extra stability to the installed aerofoils. It is preferred that the aerofoils are attached to the upper surfaces of the bluff bodies. It may be desirable however for mounting brackets to attach to both the tops and sides of the bluff bodies, to provide additional tension to the aerofoils.

Figure 25 shows an end plate 45 for use in mounting an intermediate aerofoil to a container. The end plate includes a socket 47 for receipt of a central part of the aerofoil. Mounted through an aperture in the lower flange 51 of the end plate 45 is a twist lock pin 200 having a head 202, shaft 204, and an elongate engagement part 206. In use, the end plate 45 (and 30 attached aerofoil) is placed on the container, with the twist lock pin 200 positioned so that the long part of the elongate attachment part 206 is aligned with the long part of the twist lock socket 208 of the container 210. Once the elongate attachment part is within the socket, the head 202 is turned which causes the elongate attachment part 206 of the pin 200 to turn inside the socket 208, thereby attaching the aerofoil to the container. It will be 5 appreciated that the same arrangement will be provided at the other end of the container. To remove the aerofoil from the container, the pin 200 is turned so that the long part of the elongate attachment part 206 is again aligned with the long part of the twist lock socket 208, so that the pin can be removed from the socket. A similar configuration could also be used to attach the leading or trailing aerofoils to respective containers.

An alternative connector for connecting the aerofoils to twist lock sockets in containers is shown in Figure 26. A pair of spaced apart substantially J-shaped connectors 300 (only one of which is shown in the Figure) extend downwardly from the aerofoil A, and are sized and spaced for receipt in respective twist lock sockets 302 of a container 304. To mount the 15 aerofoil A on the container 304, the aerofoil is tilted forwardly so that the lower ends of the connectors 300 are directed toward the twist lock sockets 302. After the ends of the connectors 300 have been inserted into their respective sockets 302, the aerofoil is tilted rearwardly to the position shown in Figure 27. The connectors are shaped such that the aerofoil cannot be removed from the sockets without tilting it forwardly. To prevent 20 forward tilting, straps or ratchet tie downs 306 are used to connect a rearward part of the aerofoil to a lower part of the container as shown.

Any of the aerofoils could be connected using the methods described above. 26 For reference, standard container dimensions are as follows: External Container Dimensions (mm) Length Height Width ft container 6,058 2,591 2,438 40 ft container 12,192 2,326 2,438 40 ft hi-cube 12,192 2,895 2,438 The aerofoils will generally extend substantially the Ml width of the bluff body to which 5 they are attached. In the embodiment in which the mounting brackets attach to the sides of the bluff bodies, it is anticipated that they will need to extend approximately 12 mm to each side. The maximum heights of the leading edge, intermediate and trailing edge aerofoils above the top surfaces of the respective bluff bodies are preferably about 90 mm, 160 mm and 170 mm respectively.

It is preferred that the aerofoils and mounting members will be made from polymer or composite materials, to provide strength and low weight. The preferred material is a polyester impregnated glass fibre composite material with a gel coating to provide a smooth aerodynamically efficient surface.

If a lightweight material is used to make the aerofoils, the aerofoils will be relatively light and can be easily stored behind the tractor when not in use and maintained in position by the tie downs. When needed, they could easily be lifted into position using a pole or similar, and then maintained in position on the bluff body/bodies with the tie downs.

The aerofoils could be attached to curtain-sider trailers during their manufacture. Alternatively, they may be provided as an aftermarket fitting, either alone or in sets or kits. For a truck carrying or towing a single bluff body, the set preferably includes a leading edge aerofoil and a trailing edge aerofoil as described above. For a truck carrying or 25 towing two bluff bodies, the set preferably includes a leading edge aerofoil, an intermediate 27 aerofoil, and a trailing edge aerofoil as described above. The sets may also include all required mounting members, fasteners, etc.

Testing has shown that on a varying route, a tractor towing an "A" and "B" train has 5 achieved a fuel saving of about 18.4% using the preferred embodiment aerofoils. An even greater saving should be possible over a line haul route where the vehicle can be driven more towards maximum legal speed, due to the exponential increase in drag with speed. It is estimated that about 74% of the reducable drag is being reduced through the use of these aerofoils. On a flat road at constant highway speeds, a further 26% drag reduction may be 10 achievable, which would result in a total fuel saving of about 23.18% under ideal conditions.

The above describes preferred embodiments of the present invention, and modifications may be made thereto without departing from the scope of the invention.

For example, while the above preferred embodiment shows a truck comprising a tractor unit towing an "A" train and a "B" train, the devices may be used on a truck towing only an "A" train. The aerofoil directing air across the "A" and "B" train gap would not be used in such an embodiment, but the rearward vortex generator could be provided at the rear edge 20 of the "A" train. Further, a leading edge aerofoil and a trailing edge aerofoil could be used on a truck having a single bluff body such as a tray mounted container or a non-trailer curtain-sider for example.

While the above preferred embodiment shows a tractor unit towing "A" and "B" trains, the 25 principle of the invention could be extended to trucks towing further bluff bodies, such as "C", "D" trains as would be found on Australian "road trains".

Rather than the leading edge stubnose aerofoil being attached to the forward bluff body, it could be attached to or mounted on top of the tractor unit. This would be particularly 30 suitable when the bluff body does not move (turn) relative to the tractor unit when the truck 28 is in motion, such as a tractor unit with a tray-mounted container or an integral curtain-sider covered tray. Such a variant could also be used when the bluff body is trailer mounted, but it is expected that the performance would not be as satisfactory, especially when the truck is turning. However, such a configuration may be suitable for a truck which generally does 5 long distance runs on relatively straight roads.

The preferred devices described above provide a number of benefits.

Rather than simply addressing the frontal drag on the tractor unit and its load, the above 10 devices assist in minimising drag in the primary drag-inducing areas of the loaded vehicle.

The devices described above assist in containing the envelope maintaining the airflow in close proximity to the vehicle and its attached load. They address aspects of aerodynamic drag in each section of the vehicle and its load. The aerofoils entrain and shape the entire 15 flow regime so as to minimise the three main contributors to drag in a vehicle towing an "A" and "B" train. The devices reduce the size of the highest pressure area, that being the highest point of the leading edge of the "A" train. They also improve airflow across the gap between the rearward portion of the "A" train and the leading edge of the "B" train, as well as addressing the width, area and volume of the turbulent area located behind the 20 rearmost section of the "B" train. The flow wake is redirected and reduced in area both above and to the sides of the vehicle and load. The flows react about the centreline of the vehicle. The reduction in volume and frontal area of total displaced flow minimise its impact on other road users.

The above trailing edge aerofoils, by virtue of having "Horner" tips or fins minimise or prevent outer eddy turbulence, and assist in entraining airflow over the inner surfaces of the aerofoils. 29 Further, in wet conditions a reduction in spray area results, enhancing safety by providing a wider angle of view for both the truck driver to the rear and for other road users in passing situations.

The reduction in drag results in a reduction in horsepower and therefore fuel consumption required to overcome it.

It is estimated that under idealized flow, with the air flow approaching the vehicle from directly ahead of the vehicle, drag reductions of up to 57% are achievable, and it is 10 expected that using the aerofoils described herein as well as reducing weight could assist in achieving fuel savings of up to 40%.

The aerofoils are preferably attachable and detachable from the trailers) or containers), meaning that a user is able to purchase one such set of aerofoils for use with different loads. 15 The aerofoils may be attachable to a container without interference with the containers' swinging doors or the container truck's swing loading apparatus.

The aerofoils also offer a slight drag reduction when airflow approaches the vehicle at an angle (ie when driving in crosswinds or when turning). However, long haul routes will 20 show the greatest grains from the use of the aerodynamic devices.

Other safety benefits which may result from the use of the preferred aerofoils include: • improved tracking ability, resulting in less trailer sway in overtaking manoeuvres; • shorter overtaking time, due to greater acceleration by aerodynamic drag reduction; 25 • a lowering of rearward amplification, as the degree to which the trailing units amplify or exaggerate the lateral motions of the tractor unit is reduced by the aerodynamic coupling between the "A" and "B" train and the vortices induced at the rear of the last component of the train. As the forces generated by the combination of the three aerofoils act in two planes, and with the larger of the three forces acting behind and on the centerline of the vehicle, the "righting" effect acts on the towed train; • improved braking in a straight path, due to inducement and direction of the flow from the rear vortex generators, the drag becomes centred on the centerline of the vehicle. Without such vortex generators, the rearmost trailer unit can move over a greater arc within the wide zone of turbulence caused by the bluff rear panel before it meets the relative laminar airstream generated by the forward motion of the vehicle; • safer lane changing at highway speeds, as the aerodynamic devices exert their effect 10 on the airstream at an angle but parallel with the span (across and parallel with the roof of the vehicle), thereby exerting a righting couple which counters any sudden changes to the flow regime of the towed train; • yaw damping. Oscillations imposed on the vehicle and its train as a result of road undulations are damped by the aerofoils, and decay rates are therefore of a shorter duration than for vehicles without attached aerofoils; • minimisation of high speed transient off-tracking caused by sudden evasive manouevres, as greater aerodynamic forces are imposed as vehicle speed increases; and • a lowering of driver fatigue, due to the improvements in tracking ability, resulting in 20 less driver exertion and resulting tiredness.

It should be appreciated that not all of the advantages or benefits outlined above necessarily apply to every embodiment. 31

Claims (74)

WHAT WE CLAIM IS:

1. A leading edge aerofoil for reducing drag on a truck towing or carrying at least one bluff body as a load, the aerofoil having a curved nose and an upper surface angled away 5 from the curved nose and a lower surface extending rearwardly from the curved nose, with the vertical distance from the lowest point of the lower surface to the most forward part of the curved nose being less than the vertical distance from the upper point of the upper surface to the most forward part of the curved nose, the aerofoil configured for attachment to the most forward bluff body of the load or to the top of a tractor unit with a rear part of 10 the upper surface substantially aligned with an upper surface of the most forward bluff body of the load and with a space provided below the lower surface of the aerofoil, such that the aerofoil assists in attaching oncoming airflow to the upper surface of the most forward bluff body, thereby reducing air drag. 15

2. A leading edge aerofoil as claimed in claim 1, wherein the aerofoil is configured for attachment to a forward surface of the most forward bluff body.

3. A leading edge aerofoil as claimed in claim 1 or 2, wherein the aerofoil is configured to produce lift and laminar flow, thereby assisting in attaching oncoming 20 airflow to the upper surface of the bluff body in use.

4. A leading edge aerofoil as claimed in any one of claims 1 to 3, wherein the aerofoil has a span defined by its width and a chord defined by the distance from the most forward part of the nose to a trailing edge, and wherein the ratio of aerofoil span to aerofoil chord is 25 between about 7:1 and about 9:1.

5. A leading edge aerofoil as claimed in any one of claims 1 to 5, wherein the aerofoil has a chord defined by the distance from the most forward part of the nose to a trailing edge and a maximum thickness defined by the maximum distance between the upper surface and i intellectual property 0t+iut of n.z ,08227-5 - 9 MAR 2005 RECEIVED 32 the lower surface, and wherein the ratio of aerofoil chord to maximum aerofoil thickness is between about 1.1:1 and about 1.4:1.

6. A leading edge aerofoil as claimed in any one of claims 1 to 5, wherein the lower 5 surface is angled away from the curved nose.

7. A leading edge aerofoil as claimed in claim 6, wherein the upper surface generally extends rearwardly from the nose with a greater angle than the lower surface.

8. A leading edge aerofoil as claimed in claim 6 or 7, wherein the aerofoil has a maximum thickness defined by the maximum distance between the upper surface and the lower surface, and wherein the vertical distance from the lowest point of the lower surface to the most forward part of the curved nose is between about 22% and 33% of the maximum thickness.

9. A leading edge aerofoil as claimed in any one of claims 1 to 8, wherein the aerofoil has a chord defined by the distance from the most forward part of the nose to a trailing edge and the radius of the nose is about 40% of the aerofoil chord. 20

10. A leading edge aerofoil as claimed in any one of claims 1 to 9, including end plates or fins extending upwardly from respective ends of the aerofoil, which end plates or fins are arranged to assist in entraining air flow over the aerofoil in use.

11. A leading edge aerofoil as claimed in claim 10, wherein the end plates or fins 25 extend rearwardly and above an upper rear edge of the aerofoil.

12. A leading edge aerofoil as claimed in any one of claims 1 to 11, including attachment means for attaching the aerofoil to the most forward bluff body. 108227-5 intellectuau>r0pertv office - 9 MAR 2005 RECEIVED 33

13. A leading edge aerofoil as claimed in claim 12, wherein the attachment means includes flanges configured to engage one or more surfaces of the most forward bluff body.

14. A leading edge aerofoil as claimed in claim 12, wherein the attachment means is 5 configured to engage twist lock or cam lock sockets on a container.

15. A leading edge aerofoil as claimed in claim 14, wherein the attachment means includes a pair of spaced apart twist lock or cam lock pins configured for receipt in the twist lock or cam lock sockets.

16. A leading edge aerofoil as claimed in claim 14, wherein the attachment means includes a pair of substantially J-shaped connectors configured for receipt in complementary twist lock or cam lock sockets in the container and configured such that the aerofoil must be tilted to remove it from the container.

17. A set of aerofoils for reducing drag on a truck towing or carrying at least one bluff body as a load, including a leading edge aerofoil as claimed in any one of the preceding claims and a trailing edge aerofoil which is configured for attachment at or adjacent the trailing edge of the most rearward bluff body of the load, and which is configured to reduce 20 the area and volume of the load's turbulent flow in use, thereby reducing air drag.

18. A set of aerofoils as claimed in claim 17, wherein the trailing edge aerofoil has a central portion with a curved leading edge and a relatively sharp trailing edge. 25

19. A set of aerofoils as claimed in claim 18, wherein the trailing edge aerofoil has a span defined by its width and a chord defined by the distance from the leading edge of the trailing edge aerofoil to the trailing edge of the trailing edge aerofoil, and wherein the ratio of aerofoil span of the trailing edge aerofoil to aerofoil chord of the trailing edge aerofoil is between about 3.75:1 and about 4.25:1. 10 15 30 intellectual property office of n.z. mmtpi i.ectiial propfrtv opfice I nt in at in 108227-5 -9 MAR 2M5 RECEIVED -9 MAS 2055 34

20. A set of aerofoils as claimed in claim 19, wherein the ratio of aerofoil span of the trailing edge aerofoil to aerofoil chord of the trailing edge aerofoil is about 4.1:1.

21. A set of aerofoils as claimed in any one of claims 18 to 20, wherein the trailing edge 5 aerofoil has a chord defined by the distance from the leading edge of the trailing edge aerofoil to the trailing edge of the trailing edge aerofoil and a maximum thickness defined by the maximum distance between an upper surface of the trailing edge aerofoil and a lower surface of the trailing edge aerofoil, and wherein the size of the maximum thickness of the trailing edge aerofoil is between about 8.1% and 13.5% of the size of the chord of the 10 trailing edge aerofoil.

22. A set of aerofoils as claimed in claim 21, wherein the size of the maximum thickness of the trailing edge aerofoil is about 13.2% of the size of the chord of the trailing edge aerofoil. 15

23. A set of aerofoils as claimed in any one of claims 18 to 22, wherein the trailing edge aerofoil has a maximum thickness defined by the maximum distance between the upper surface of the trailing edge aerofoil and the lower surface of the trailing edge aerofoil, and wherein the vertical distance from the lowest point of the lower surface of the trailing edge 20 aerofoil to the forward most portion of the curved leading edge of the trailing edge aerofoil is between about 35% and 40% of the maximum aerofoil thickness of the trailing edge aerofoil.

24. A set of aerofoils as claimed in any one of claims 18 to 23, wherein the trailing edge 25 aerofoil has a maximum thickness defined by the maximum distance between the upper surface of the trailing edge aerofoil and the lower surface of the trailing edge aerofoil, and wherein the radius of the curved leading edge of the trailing edge aerofoil is between about 30% and about 35% of the maximum thickness of the trailing edge aerofoil. 108227-5 intellectual property office i of N.Z -9 MAR 2005 —RECEIVED 35

25. A set of aerofoils as claimed in claim 24, wherein the radius of the curved leading edge of the trailing edge aerofoil is about 33.3% of the maximum thickness of the trailing edge aerofoil. 5

26. A set of aerofoils as claimed in any one of claims 17 to 25, wherein the trailing edge aerofoil includes at least one vortex generating projection to induce a rearward vortex in use.

27. A set of aerofoils as claimed in claim 26, wherein the trailing edge aerofoil includes 10 a pair of vortex generating tips at the ends of the aerofoil.

28. A set of aerofoils as claimed in claim 27, wherein the tips of the trailing edge aerofoil extend rearwardly, the tips being arranged so that in use two vortices of opposite sense are generated, confining drag to a smaller area. 15 20

29. A set of aerofoils as claimed in claim 28, wherein the tips of the trailing edge aerofoil are arranged so that in use, as the vortices travel rearwardly they enlarge in diameter and impinge on each other, pulling turbulent airstream which is exiting from the underside of the vehicle into a substantially constant flow regime.

30. A set of aerofoils as claimed in any one of claims 27 to 29, configured such that the tips of the trailing edge aerofoil extend upwardly when the trailing edge aerofoil is attached to the bluff body. 25 31. A set of aerofoils as claimed in claim 30, wherein the trailing edge aerofoil has a chord defined by the distance from a leading edge of the trailing edge aerofoil to a trailing edge of the trailing edge aerofoil, and wherein the tips extend rearwardly of the trailing edge of the trailing edge aerofoil by about 25% of the chord of the trailing edge aerofoil. 108227-5 ^ intellectual property office of n.z -9 MAR 2005

RECEIVED 36

32. A set of aerofoils as claimed in claim 30 or 31, wherein the trailing edge aerofoil has a maximum thickness defined by the maximum distance between an upper surface of the trailing edge aerofoil and a lower surface of the trailing edge aerofoil, and wherein the rise of each tip directly above the point of maximum thickness of the trailing edge aerofoil 5 is about 14% of the maximum thickness of the trailing edge aerofoil.

33. A set of aerofoils as claimed in any one of claims 17 to 32, wherein the trailing edge aerofoil is configured for attachment to the most rearward bluff body so that its point of maximum lift is located substantially directly above the trailing edge of the bluff body, and 10 so that a gap is provided between the lower surface of the trailing edge aerofoil and the trailing edge of the bluff body.

34. A set of aerofoils as claimed in any one of claims 17 to 33, wherein the trailing edge aerofoil is configured for attachment at or adjacent the trailing edge of the most rearward 15 bluff body of the load with a positive angle of attack relative to oncoming airflow, to downwardly direct oncoming airflow.

35. A set of aerofoils as claimed in any one of claims 17 to 34, including attachment means for attaching the trailing edge aerofoil at or adjacent the trailing edge of the most 20 rearward bluff body of the load.

36. A set of aerofoils as claimed in claim 35, wherein the attachment means for attaching the trailing edge aerofoil includes flanges configured to engage one or more surfaces of the most rearward bluff body. 25

37. A set of aerofoils as claimed in claim 35, wherein the attachment means for attaching the trailing edge aerofoil is configured to engage twist lock or cam lock sockets on a container. 108227-5 omcE I -9 MAR 20® RECEIVED. 37

38. A set of aerofoils as claimed in claim 37, wherein the attachment means for attaching the trialing edge aerofoil includes a pair of spaced apart twist lock or cam lock pins configured for receipt in the twist lock or cam lock sockets. 5

39. A set of aerofoils as claimed in claim 37, wherein the attachment means for attaching the trailing edge aerofoil includes a pair of substantially J-shaped connectors configured for receipt in complementary twist lock or cam lock sockets in the container and configured such that the trailing edge aerofoil must be tilted to remove it from the container. 10

40. A set of aerofoils as claimed in any one of claims 17 to 39 for reducing drag on a truck towing or carrying at least two bluff bodies as a load, including an intermediate aerofoil which is configured for attachment at or adjacent the upper trailing edge of the most forward of the bluff bodies of the load, and which is configured in use to direct 15 airflow over the gap between the most forward bluff body and the following bluff body and toward the upper surface of the following bluff body in use, thereby reducing air drag.

41. A set of aerofoils as claimed in claim 40, wherein the intermediate aerofoil has a central portion with a curved leading edge and a relatively sharp trailing edge. 20

42. A set of aerofoils as claimed in claim 41, wherein the intermediate aerofoil has a span defined by its width and a chord defined by the distance from the leading edge of the intermediate aerofoil to the trailing edge of the intermediate aerofoil, and wherein the ratio of aerofoil span of the intermediate aerofoil to aerofoil chord of the intermediate aerofoil is 25 between about 5.5:1 and about 6:1.

43. A set of aerofoils as claimed in claim 42, wherein the ratio of aerofoil span of the intermediate aerofoil to aerofoil chord of the intermediate aerofoil is about 5.8:1. 108227-5 inteliectual^property ofice -9 MAR 2005 R EC EIVED 38

44. A set of aerofoils as claimed in any one of claims 41 to 43, wherein the intermediate aerofoil has a chord defined by the distance from the leading edge of the intermediate aerofoil to the trailing edge of the intermediate aerofoil and a maximum thickness defined by the maximum distance between an upper surface of the intermediate aerofoil and a lower 5 surface of the intermediate aerofoil, and wherein the size of the maximum thickness of the intermediate aerofoil is between about 8.1% and about 13.5% of the size of the chord of the intermediate aerofoil.

45. A set of aerofoils as claimed in claim 44, wherein the size of the maximum 10 thickness of the intermediate aerofoil is about 13% of the size of the chord of the intermediate aerofoil.

46. A set of aerofoils as claimed in any one of claims 41 to 45, wherein the intermediate aerofoil has a maximum thickness defined by the maximum distance between the upper 15 surface of the intermediate aerofoil and the lower surface of the intermediate aerofoil, and wherein the vertical distance from the lowest point of the lower surface of the intermediate aerofoil to the forward most portion of the curved leading edge of the intermediate aerofoil is between about 35% and 60% of the maximum aerofoil thickness of the intermediate aerofoil. 20 25

47. A set of aerofoils as claimed in claim 46, wherein the vertical distance from the lowest point of the lower surface of the intermediate aerofoil to the forward most portion of the curved leading edge of the intermediate aerofoil is about 58% of the chord of the intermediate aerofoil.

48. A set of aerofoils as claimed in any one of claims 41 to 47, wherein the intermediate aerofoil has a maximum thickness defined by the maximum distance between the upper surface of the intermediate aerofoil and the lower surface of the intermediate aerofoil, and wherein the radius of the curved leading edge of the intermediate aerofoil is between about 30 15% and about 20% of the maximum thickness of the intermediate aerofoil. 108227-5 intellectual property office of n.z - 9 MAR 2085 RECEIVED 39

49. A set of aerofoils as claimed in claim 48, wherein the radius of the curved leading edge of the intermediate aerofoil is about 17% of the maximum thickness of the intermediate aerofoil. 5

50. A set of aerofoils as claimed in any one of claims 41 to 49, wherein the intermediate aerofoil includes a pair of upwardly extending members or projections at respective ends to assist in entraining airflow over the surface of the central portion of the intermediate aerofoil. 10

51. A set of aerofoils as claimed in claim 50, wherein the intermediate aerofoil has a maximum thickness defined by the maximum distance between an upper surface of the intermediate aerofoil and a lower surface of the intermediate aerofoil, and wherein the members or projections extend above the trailing edge of the intermediate aerofoil by about 15 the maximum thickness of the intermediate aerofoil.

52. A set of aerofoils as claimed in claim 50 or 51, wherein the intermediate aerofoil has a chord defined by the distance from the leading edge of the intermediate aerofoil to the trailing edge of the intermediate aerofoil, and wherein the members or projections extend 20 forwardly of the leading edge of the intermediate aerofoil by about 5% of the chord of the intermediate aerofoil.

53. A set of aerofoils as claimed in any one of claims 40 to 52, wherein the intermediate aerofoil has a maximum thickness defined by the maximum distance between an upper 25 surface of the intermediate and a lower surface of the intermediate aerofoil, and wherein the intermediate aerofoil is configured for attachment to the most forward bluff body so that its point of maximum thickness is located substantially directly above the trailing edge of the bluff body, and so that a gap is provided between the lower surface of the intermediate aerofoil and the trailing edge of the bluff body. 30 108227-5 intellectual property office of n.z -9 MAR 2005 RECEIVED 40

54. A set of aerofoils as claimed in any one of claims 40 to 53, wherein the intermediate aerofoil has a central portion with a curved leading edge and a relatively sharp trailing edge, and wherein the intermediate aerofoil is configured for attachment at or adjacent the trailing edge of the most forward of the bluff bodies of the load such that the central portion 5 of the intermediate aerofoil has a positive angle of attack relative to oncoming airflow, to downwardly direct oncoming airflow.

55. A set of aerofoils as claimed in claim 54, wherein the angle of attack of the central portion of the intermediate aerofoil is about 2 degrees. 10

56. A set of aerofoils as claimed in any one of claims 40 to 55, including attachment means for attaching the intermediate aerofoil at or adjacent the trailing edge of the most forward of the bluff bodies of the load. 15

57. A set of aerofoils as claimed in claim 56, wherein the attachment means for attaching the intermediate aerofoil includes flanges configured to engage one or more surfaces of the most forward of the bluff bodies.

58. A set of aerofoils as claimed in claim 56, wherein the attachment means for 20 attaching the intermediate aerofoil is configured to engage twist lock or cam lock sockets on a container.

59. A set of aerofoils as claimed in claim 58, wherein the attachment means for attaching the intermediate aerofoil includes a pair of spaced apart twist lock or cam lock 25 pins configured for receipt in the twist lock or cam lock sockets.

60. A set of aerofoils as claimed in claim 58, wherein the attachment means for attaching the intermediate aerofoil includes a pair of substantially J-shaped connectors configured for receipt in complementary twist lock or cam lock sockets in the container and 30 configured such that the aerofoil must be tilted to remove it from the container. 108227-7 intellectual property cftiii?! OF i\LZ 2 6 APR 1305 RECEIVED 41

61. A leading edge aerofoil as claimed in any one of claims 1 to 16, when attached to the most forward bluff body of a load being towed or carried by a truck, or when attached to the top of the tractor unit, such that a rear part of the upper surface is substantially aligned with an upper surface of the most forward bluff body and a space is provided below 5 the lower surface of the aerofoil.

62. A set of aerofoils as claimed in any one of claims 17 to 39, when the leading edge aerofoil is attached to the most forward bluff body of a load being towed or carried by a truck, or when attached to the top of the tractor unit, such that a rear part of the upper 10 surface is substantially aligned with an upper surface of the most forward bluff body and a space is provided below the lower surface of the aerofoil, and when the trailing edge aerofoil is attached at or adjacent the trailing edge of the most rearward bluff body of the load being towed or carried by a truck. 15

63. A set of aerofoils as claimed in any one of claims 40 to 60, when the leading edge aerofoil is attached to the most forward bluff body of a load being towed or carried by a truck, or when attached to the top of the tractor unit, such that a rear part of the upper surface is substantially aligned with an upper surface of the most forward bluff body and a space is provided below the lower surface of the aerofoil, and when the trailing edge 20 aerofoil is attached at or adjacent the trailing edge of the most rearward bluff body of the load being towed or carried by a truck, and when the intermediate aerofoil is attached at or adjacent the trailing edge of the most forward bluff body of the load being towed or carried by a truck. 25

64. A truck towing or carrying at least one bluff body as a load, including a leading edge aerofoil as claimed in any one of claims 1 to 16 attached to the most forward bluff body of the load or to the top of a tractor unit, with the upper surface of the aerofoil substantially aligned with an upper surface of the most forward bluff body of the load and with a space provided below the lower surface of the aerofoil, to assist in attaching 108227-5 intellectual property office of n.z -9 MAR 2005 RECEIVED t 42 oncoming airflow to the upper surface of the most forward bluff body, thereby reducing air drag.

65. A truck towing or carrying at least one bluff body as a load, including a set of 5 aerofoils as claimed in any one of claims 17 to 39, with the leading edge aerofoil attached to the most forward bluff body of the load or to the top of a tractor unit, with the upper surface of the aerofoil substantially aligned with an upper surface of the most forward bluff body of the load and with a space provided below the lower surface of the aerofoil, to assist in attaching oncoming airflow to the upper surface of the most forward bluff body, and with 10 the trailing edge aerofoil attached at or adjacent the trailing edge of the most rearward bluff body of the load, to reduce the area and volume of the load's turbulent flow, thereby reducing air drag.

66. A truck towing or carrying at least two bluff bodies as a load, including a set of 15 aerofoils as claimed in any one of claims 40 to 60, with the leading edge aerofoil attached to the most forward bluff body of the load or to the top of a tractor unit, with the upper surface of the aerofoil substantially aligned with an upper surface of the most forward bluff body of the load and with a space provided below the lower surface of the aerofoil, to assist in attaching oncoming airflow to the upper surface of the most forward bluff body, and with 20 the trailing edge aerofoil attached at or adjacent the trailing edge of the most rearward bluff body of the load, to reduce the area and volume of the load's turbulent flow, and with the intermediate aerofoil attached at or adjacent the upper trailing edge of the most forward of the bluff bodies of the load and configured to direct airflow over the gap between the most forward bluff body and the following bluff body and toward the upper surface of the 25 following bluff body, thereby reducing air drag.

67. A set of aerofoils as claimed in any one of claims 17 to 60, including attachment means for attaching the aerofoil(s) to the bluff body or bodies and configured such that the aerofoil(s) can be interchanged between one bluff body and another. 30 intellectual property office 108227-5 of n.z -9 MAR 2005 RECEIVED 43

68. A method of streamlining a truck carrying or towing one or more bluff bodies, including fitting a leading edge aerofoil as claimed in any one of claims 1 to 16 to the most forward bluff body or tractor unit, or a set of aerofoils as claimed in any one of claims 17 to 60 to one or more bluff bodies. 5

69. A method of streamlining a truck as claimed in claim 68, wherein the truck is loaded to tow or carry only a single bluff body and the method includes fitting a leading edge aerofoil as claimed in any one of claims 1 to 16 to the most forward bluff body or tractor unit such that the rear part of the upper surface of the aerofoil is substantially 10 aligned with the upper surface of the most forward bluff body and a space is provided below the lower surface of the aerofoil, and fitting a trailing edge aerofoil of the set as claimed in any one of claims 17 to 60 at or adjacent the upper trailing edge of the bluff body. 15

70. A method of streamlining a truck as claimed in claim 68, wherein the truck is loaded to tow or carry two bluff bodies and the method includes fitting a device as claimed in any one of claims 1 to 16 to the most forward bluff body or tractor unit such that the rear part of the upper surface of the aerofoil is substantially aligned with the upper surface of the most forward bluff body and a space is provided below the lower surface of the aerofoil, 20 fitting an intermediate aerofoil of the set as claimed in any one of claims 40 to 60 at or adjacent the upper trailing edge of the most forward bluff body, and fitting a trailing edge aerofoil of the set as claimed in any one of claims 17 to 60 at or adjacent the upper trailing edge of the most rearward bluff body. 25

71. A leading edge aerofoil for streamlining a bluff body which is towed or carried by a truck, substantially as hereinbefore described with reference to Figures 4, 5b, and 9-11.

72. A leading edge aerofoil as claimed in any one of claims 1 to 16, substantially as herein described with reference to any embodiment disclosed. 30 108227-5 intellectual property office of n.z -9 MAR 2005 RECEIVED 44

73. A set of aerofoils as claimed in any one of claims 17 to 60, substantially as herein described with reference to any embodiment disclosed.

74. A set of aerofoils, substantially as hereinbefore described with reference to Figures 4,5b, 6a-c, and 9-26. ■■■ r - ■ 108227-5 INTELLECTUAL PROPERTY 0FICE OF Ml - S MAR 2005 RECEIVED