GB2478570A

GB2478570A - Air moving apparatus for increasing flow over aerofoil surfaces

Info

Publication number: GB2478570A
Application number: GB1003985A
Authority: GB
Inventors: Edward Philip Ian Whittaker
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-03-11
Filing date: 2010-03-11
Publication date: 2011-09-14
Anticipated expiration: 2030-03-11
Also published as: GB201003985D0; GB2478570B

Abstract

An air moving apparatus is formed by an outer box and an inner box made up of curved surfaces F. A plenum chamber F is created between the two boxes and is supplied with pressurised gas J via an inlet pipe E. A flow of gas G passes through two opposed and substantially parallel slits formed between curved surfaces H and lips X. The gas is exhausted through outlet B and passes over curved surface C. The gas flow induces a flow of ambient gas K which is entrained into the flow G and which is then exhausted at B. The apparatus may take the form of devices P and Q which can be deployed from aerofoil surfaces S and T. A combination of the devices may provide lifting forces for transition into hover from forward flight with a suitable low velocity aerofoil.

Description

An improved Mechanism To Deploy Controlled Flows and Forces Over Surfaces The invention relates to a means of implementing and controlling a lifting structure of the type for use in supporting attached bodies, including vehicles, manned or unmanned, in air.

Such lifting structures normally rely on forward motion relative to the air mass for obtaining their lift from the flow of air over the top and bottom surfaces, and do not provide adequate lift when stationary or moving with little velocity relative to the general air mass.

The invention was conceived when designs were called for in the 1994 RaeS Light Aircraft Design competition.

The initial designs consisted of means to channel gases from an airscrew or turbine over an aerofoil structure, being based on the demonstration airfoil in Birmingham Science Museum, but were dismissed as too obvious.

An object of this invention is to provide a means of moving gases over the surface or surfaces of the structure to provide lift and other forces when there is little or no movement of the structure as a whole relative to the general mass of the air.

There have been other attempts to use the Coanda effect for this purpose, mainly to assist lift or provide enhanced control. Many rely on a single slit and use either complex delivery, or are crude, noisy and inefficient in their use of the power in the primary mover gases.

Accordingly this invention provides a structure and components that allow pressurised / compressed gases to be delivered, if required by a plenum chamber from whence it may be further delivered or, directly to a Coanda' device mounted at either one, or several positions around, over and under the said structure in order to provide air flows across the surface or surfaces of the structure, when in any attitude relative to the ground or the surrounding air mass, to provide lift or any other appropriately directed force derived from the action of the directed air flow over the surface of the structure.

The Coanda' device described is one that typically consists of opposed slits, and surfaces arranged so as to induce an air flow between them that augments the gas flow from the slits themselves by the entraining Bernouilli effect, thereby magnifying considerably the volume of gases available, (similar in effect to industrial air movers, which however are usually in a circumferential layout), to be directed over the surfaces of the structure.

When not required for producing these forces this device may be rotated or otherwise retracted, depending on the style of its embodiment to leave a typical aerofoil edge shape if mounted there, or to otherwise form a part of the aerofoil surface of the resultant structure.

It is envisaged that any vehicle employing the device would do so with a multiplicity of devices in order to provide stability and control.

The structure may embody other known and new devices for enhancing the forces derived from use of the structure, as well as aerofoil extensions that may come into play for use during normal flight in relative motion conditions.

It is envisaged that the device could be deployed initially in perch and stare' and hover in place' applications where quiet operation is essential.

Description of Drawing Sheet 1/1

An embodiment of the invention will now be described with reference to the accompanying drawing sheet 1/1, in which it is envisaged that that compressed gas would be produced adjacent to the device, or stored similarly.

Gas is led to the device either through flexible or articulated piping and flow to the device is controlled by proportional valves.

Figure 1 shows the device as a rectangular section box, with a lip X at A,and with rear outlet B adjacent to a curved surface C, within which is a second box D, attached, creating a plenum between outer and inner.

The gas inlet pipe E is attached in such a way as to lead the gas J into that plenum chamber.

Figure 2 shows a cross section of the device with gas leaving the plenum chamber F at the front G and following the curved inner surface H according to the Coanda effect, and thereby entraining external gases K. In this embodiment the gases also leave via I on the short edges (Figure 1) Figure 3 shows the device at L and M with its outer surface flush with the surface of a high lift aerofoil section, that is, in the undeployed mode, together with another at N that is capable of being rotated back and out.

Figure 4 shows the device deployed at P and Q by mechanical or electromechanical means to sit with its inner surface R flush with the aerofoil surface S and T thereby forcing a flow of both compressed and entrained gases over the curved section providing appropriate forces V and W on the aerofoil.

Figure 5 shows the device in positions P and N deployed and retracted at M. At N the rear portion of the aerofoil has been rotated outwards and downwards exposing the inlet and outlet of the device. The flow at the concave surface, underside, is reversed, setting up a circular flow around the aerofoil creating lift for hovering flight.

Claims

CLAIMSA structure comprising a surface, curved as required, attached to which a means of storing and/or channelling gases from a pressurised supply through a double parallel slit Coanda device positioned as to direct those gases and such entrained ambient gases over the surface, and other surfaces, in order to provide forces with components normal to those surfaces.l.A structure as in Claim 1 with a plenum chamber and controllable gas valves.
2.A structure as in Claim 1 & 2 with proportional gas valves.
3.A structure as in Claims 2 & 3 with remotely controlled gas valves.
4.A structure as in Claim 2 but without a plenum chamber.
5.A structure as in Claim 2,3,4 & 5 but with a multiplicity of Coarida devices.
6.A structure as in Claims 2,3,4,5&6 but including single slit Coanda devices.
7.A structure as in Claims 2,3,4,5,6&7 wherein the Coanda devices are adapted to retract into the structure.
8.A structure as in Claim 8 wherein the structure is capable of rotating out from the rear of an aerofoil to expose its ingress and egress such that a rotating gas flow is effected around the aerofoil.
9.A structure as in Claim 8 wherein the bottom of the retracting device forms a temporary integral surface with the surrounding surface when deployed.
lO.A structure as in Claim 8 Wherein the top of the retractable device forms a temporary integral surface with the surrounding surface when retracted.
11.A structure as in Claims 1 to 8 and 10 wherein the leading edge is adapted to project forward to reduce scavenging of ambient gases from adjacent surfaces.
12.A structure as in Claims 1 to 11 wherein the trailing surface is of porous material for the purpose of flow adhesion.
13.A structure as in Claims 8 10 and 11 wherein the device may be rotated about an axis normal to the surface.
14.A structure as in Claim 8,9,10 & 13 wherein the deployment and retraction is effected by the flow of gas from the valves,by means of a vane valve.
15.A structure as in Claims 8,9,10,11,12 & 14 wherein deployment, retraction and/or rotation is effected by piezo or other electromechanical actuators.
16.Multiple structures as in Claims 1 to 16 conjoined to effect movement and attitude control.Amended claims have been filed as follows:-CLAIMS1. A compressible fluid (typically air) amplifying and moving apparatus, capable of producing enhanced fluid flows from injected compressible fluids, together with an associated aerodynamic surface, or surfaces, the air moving apparatus part comprising a double walled structure containing twin opposed parallel slits inside the front end of its containment shell, angled according to prior art, the space between the walls being of any length between the slit and the rear, and capable of containing compressed gases that are led to the device and controlled by valves, either in or remote of the device, and that can be ejected over and adjacent to the inner walls convexly curved at that point and running from front to back inside the inner enclosed void, thereby entraining gases (ambient air) at the front end, most or all of which is then ejected at the rear, having been positioned so as to impinge tangentially over the associated aerodynamic surface whose motion it is required to affect by the resultant normal forces engendered on it. The air moving portion Q of the device may be adapted as to being retractable in and out of any carrying structure or may be rotated in 14) or out to produce enhanced flows over the associated surfaces when deployed,or may be capable of rotation about an axis at any angle to the carrying structure, or may be fixed with removable covers to the inlet and outlet, and in these retractable and rotatable versions the bottom and top of the air moving portion may be constructed so as to form a surface integral with the surrounding surface of the carrying structure when in either the fully deployed or non deployed state, the motion of deployment being effected by any of the usual actuator means, for example piezo, electro-mechanical, air vane.2. A multiplicity of devices as in Claim 1 available to a given carrying structure conjoined to effect movement and attitude control.3. A device as in Claim 1 wherein the air moving portion, being capable of rotation out from the rear of a carrying aerofoil structure to expose its ingress and egress produces a rotating gas flow about the chord over the associated aerodynamic surfaces.4. A device as in Claim 1, wherein the air moving portion is fixed near the rear of a carrying aerofoil surface such that it can produce a rotating gas flow about the chord over the associated aerodynamic surfaces when its ingress and egress ports are uncovered.5. A device as in Claims 1,and 2, wherein the leading edge is adapted to project forward to reduce scavenging of ambient gases from adjacent surfaces.6. A device as in Claims 1, and 2, wherein the ejected flow is directed to the associated aerodynamic surfaces in order to produce lift, downforce, or sideways Q component force, in order to control rolling, braking, yawing and pitching in the carrying structure. L()7. A device as in Claims 1, and 2, wherein the eiected flow is directed to the associated aerodynamic surface at a wingtip to control the vortex induced drag there.