Abstract: Example implementations relate to simple to manufacture flap assemblies with failsafe jam-resistant flap tracks. An example flap assembly may include a track having an elongate structure and a flap carriage configured to move along a length of the track. The track is configured to couple to an aircraft wing and the flap carriage includes a primary roller and a pair of secondary rollers configured to secure the flap carriage to the track. A top portion of the flap carriage is configured to couple to a flap such that movement of the flap carriage along the length of the track enables movement of the flap relative to the aircraft wing.

Abstract: An aircraft and an aircraft wing assembly for an aircraft. The wing assembly includes a wing body assembly including a wing body; and at least one protruding portion connected to the wing body. The protruding portion extends aftwardly from an aft side of the wing body assembly, a leading edge of the wing body assembly defining a leading edge line, a trailing edge of the wing body assembly defining a trailing edge line extending between the inboard end and the outboard end, the trailing edge including a trailing edge of the protruding portion, the trailing edge line being a smooth line, a chord distance being defined longitudinally from the leading edge line to the trailing edge line, the chord distance at a center of the protruding portion being greater than the chord distance inboard of protruding portion and outboard of the protruding portion.

Abstract: An aircraft beacon light for an aircraft wing with a foldable wing tip includes a housing, a lens cover, and at least one light source arranged between the housing and the lens cover, wherein the aircraft beacon light is configured to emit flashes of red light in operation, and wherein the housing and the lens cover are shaped to embed the aircraft beacon light into a hinge assembly coupling the foldable wing tip to a main wing portion of the aircraft wing.

Abstract: A leading edge slat of a wing element of an aircraft. The aircraft defining a mark including a main fuselage axis x and a spanwise axis y. The wing procuring a lift along an axis z. The wing element having a skin forming the leading edge slat, a spar linked to the skin and a stiffening structure linked on the leading edge side to the spar and to the skin. The stiffening structure being formed from a formed sheet metal having a plurality of bosses distributed according to the length of the leading edge. The bosses extending between the spar and the inner face of the skin.

Abstract: Methods, apparatus, and articles of manufacture to extend a leading-edge vortex of a highly-swept wing aircraft wing are disclosed. An example apparatus includes a shoulder wing coupled to a fuselage of an aircraft above a highly-swept wing of the aircraft, the shoulder wing operative in a first position to extend a leading-edge vortex spanwise along the highly-swept wing of the aircraft.

Abstract: Krueger flap apparatus and methods incorporating a bullnose having a contour variation along a spanwise direction are described. An example apparatus includes a Krueger flap having a bullnose extending in a spanwise direction. The bullnose includes a contour variation formed by a plurality of protuberances located along the bullnose. Respective ones of the protuberances are spaced along the spanwise direction.

Abstract: An aircraft (102) including a wing (101), having a fixed wing (105) with a wing tip device (103) moveably mounted at the outer end thereof. The wing tip device (103) is moveable between: a flight configuration; and a ground configuration. The wing tip device (103) and the fixed wing (105) are separated along an oblique primary cut plane (113). The wing tip device (103) and the fixed wing (105) meet along an interfacing cut line (135). The interfacing cut line (135) comprises a first length (137) offset from the primary cut plane (113) in a first direction; a second length (141) offset from the primary cut plane (113) in a second direction, opposite to the first direction; and a transition section (139) over which the interfacing cut line (135) transitions from the first length to the second length.

Abstract: An aircraft including a wing 10 having a fixed wing 12 and a swing wing tip device 14 pivotably mounted about a pivot 16 at the tip of the fixed wing, wherein the swing wing tip device 14 is configurable between a flight configuration for use during flight and a ground configuration for use during ground-based operations, where the span of the aircraft wing is reduced. The swing wing tip device 14 includes a receiving portion 48 arranged such that in the ground configuration, portions of the upper wing skin and lower wing skin of the fixed wing which are exposed in the flight configuration are at least partially received within the receiving portion 48 of the swing wing 14.

Abstract: An aircraft (40). The aircraft comprises a plurality of propellers (46) mounted to wings (44). Each propeller comprises at least one blade (72, 74) coupled to a respective propeller cyclic actuator (78) configured to cyclically alter the pitch of the respective blade (72, 74) as the propeller rotates. The aircraft (40) is configured such that provision of cyclic pitch to the propeller (46) twists at least a portion of the wing (44) about a span of the wing (46) relative to the fuselage (42), to thereby adjust the local angle of incidence of the wing (46).

Abstract: An aerofoil for an aircraft includes an engine, a first lift body, and a second lift body which is arranged behind the first lift body in the direction of flow of the aerofoil. The second lift body is pivotable relative to the first lift body between a cruising flight position in which both lift bodies together define an elongate and substantially continuous cross section of the aerofoil in the direction of flow, and a take-off/landing position in which the second lift body is angled downwards relative to the first lift body in order to increase a lift of the aerofoil.

Abstract: A deployable aerodynamic component configured to be mounted to a wind turbine. The wind turbine includes at least one rotor blade. The deployable aerodynamic component configured to be positioned in front of an inner portion of the at least one rotor blade, and is structurally configured to cover a substantial portion of the inner portion of the at least one rotor blade in a wind direction during deployment of the deployable aerodynamic component and to allow the passage therethrough of an incoming wind when non-deployed. Further described is a wind turbine including the above-described deployable aerodynamic component and method for aerodynamic performance enhancement of an existing wind turbine, wherein the method includes mounting the above-described deployable aerodynamic component to a wind turbine.

Abstract: Method and arrangement for reducing the effects of a sonic boom created by an aerospace vehicle when the vehicle is flown at supersonic speed. The method includes providing the aerospace vehicle with a first spike extending from the nose thereof substantially in the direction of normal flight of the aerospace vehicle, the first spike having a second section aft of a first section that is aft of a leading end portion, the first and second sections having a second transition region there between and each of the sections having different cross-sectional areas, the leading end portion of the first spike tapering toward a predetermined cross-section with a first transition region between the predetermined cross-section and the first section. The first transition region is configured so as to reduce the coalescence of shock waves produced by the first spike during normal supersonic flight of the aerospace vehicle.

Abstract: A profile plate portion is disclosed for use as an outer wall of a flow body including a first profile plate panel that is fluid permeable, a second profile plate panel extending along the first profile plate panel, and a reinforcing device for supporting the first profile plate panel and the second profile plate panel on one another. Fluid can flow through the reinforcing device, and/or fluid of the flow present at the first profile plate panel, which flows through the first profile plate panel, can flow through the reinforcing device in the local profile plate thickness direction from the first profile plate panel to the second profile plate panel and in some regions can flow through to an inside that is situated opposite the flow side. A method is disclosed for manufacturing a profile plate portion and a flow body component with a suction-extraction device for fluid.

Abstract: An aircraft nacelle includes a wall that delimits an inside pipe (42) that channels a stream of air to a power plant, at the front a lip (44) and on the outside an outside wall (46) that delimits a cavity (54), whereby the outside wall includes—at its inside surface—at least one stiffener (58) that is arranged in a transverse plane, characterized in that the at least one stiffener (58) includes at least one drainage opening that allows the flow of liquids through the stiffener (58) in the direction of a discharge opening (56) that is located away from the lip in such a way as to limit the risks of air being sucked inside the cavity (54).

Abstract: A swing wing tip system for an air vehicle is provided. The swing wing tip system has a swing wing tip assembly with an unfixed wing tip portion movably connected to a fixed wing portion of a wing. The swing wing tip assembly has a dual load path structure configured to transfer load from the unfixed wing tip portion to the fixed wing portion. The dual load path structure has dual wing skin plates and a rotation joint coupled between the dual wing skin plates and configured to rotationally couple the unfixed wing tip portion to the fixed wing portion. The rotation joint has a dual rotation pin element having a center rotation axis and dual rotation elements configured to rotate about the center rotation axis. The swing wing tip system has an actuator assembly coupled to the rotation joint and a controller system coupled to the actuator assembly.

Abstract: A system and method is described generally for producing surface deformations on a surface of a body. The system and method relate to a first surface being a surface of the body exposed to the fluid flow and at least one actuator affecting deformation of the first surface. A control system providing control commands to the at least one actuator is provided and a sensor providing environmental characteristic information to the control system is also provided.

Abstract: The invention relates to a wing for generating lift and comprises a trailing edge, a leading edge, an inner end, an outer end, a top surface and a bottom surface. The wing comprises an aerofoil with a chord line and a span direction. The leading edge comprises a kink between the inner end and the outer end. The leading edge comprises a forward sweep part between the inner end and the kink extending towards the kink presenting an angle relative to the span direction. The leading edge comprises a backward sweep part between the kink and the outer end extending from the kink presenting an angle relative to the span direction. The top surface comprises a flow control means for controlling the lift at least partly located between a leading edge part between the kink and the outer end and located between the leading edge and the trailing edge.

Abstract: A high-altitude unmanned stratosphere aerial vehicle includes a fuselage, wings, control surfaces, and a propulsion system including an engine and a propeller. Each wing has a plurality of hoses and wing spars extending in a direction perpendicularly to the longitudinal fuselage axis and are surrounded by a skin forming a wing covering that determines the cross-sectional contour of the wing, the cross-sectional contour forming a laminar flow airfoil that generates high lift when there is low flow resistance. At the free end facing away from the fuselage, each wing has a winglet extending transversely to the longitudinal wing axis. The winglet has a movable control surface, which allows an aerodynamic side force to be generated so as to bring the aerial vehicle to a banked position.

Abstract: Systems, equipment, and methods to deposit energy to modify and control air flow, lift, and drag, in relation to air vehicles, and methods for seeding flow instabilities at the leading edges of control surfaces, primarily through shockwave generation through deposition of laser energy at a distance.

Abstract: A system and method for producing surface deformations on a surface of a body. The system and method relate to changing the convective heat transfer coefficient for a surface. The system includes a first surface being a surface of a body exposed to a fluid flow and at least one actuator affecting deformation of the first surface. The system also includes a control system providing control commands to the at least one actuator, the control commands configured to change deformations on the first surface in order to change the convective heat transfer coefficient of the first surface. Further, the system includes a sensor providing environmental characteristic information to the control system.

Abstract: A rotation joint and methods for rotationally coupling a swing tip assembly to a fluid-dynamic body are presented. A rotation plate configured to couple to the swing tip assembly comprises a slide ring comprising an open center, an upper slide surface, an inner slide surface, and a lower slide surface. An upper joint plate is slidably coupled to the upper slide surface and the inner slide surface is configured to couple the fluid-dynamic body. A lower joint plate is slidably coupled to the lower slide surface and the inner slide surface, and is coupled to the upper joint plate through the open center. The lower joint plate is configured to couple to the fluid-dynamic body.

Abstract: A panel structure includes a composite facesheet and a stiffening core having a plurality of core members in an intersecting web configuration provided on the composite facesheet.

Abstract: Deployable aerodynamic devices with reduced actuator loads, and related systems and methods are disclosed. An external flow system in accordance with a particular embodiment includes an external flow body, a deployable device carried by and movable relative to the external flow body, and a coupling connected between the external flow body and the deployable device. The system can further include an actuator device operatively coupled between the external flow body and the deployable device, with the actuator device positioned to move the deployable device along a motion path between a stowed position and the deployed position. The motion path can have a first portion over which the load delivered by the actuator device increases as the deployed device moves toward the deployed position, and a second portion over which the load delivered by the actuator device decreases as the deployed device moves toward the deployed position.

Abstract: The invention relates to a vortex generator (10), in particular for a model (12) in a fluid-dynamic channel. In order to save time during the development of vehicles, in particular aircraft, in particular to save wind tunnel time, it is suggested to configure the vortex generator (10) switchable. Further, the invention relates to various uses of such a switchable vortex generator (10), in particular on models in fluid-dynamic channels and in fluid-dynamic channel tests.

Abstract: A rotation joint and methods for rotationally coupling a swing tip assembly to a fluid-dynamic body are presented. A rotation plate configured to couple to the swing tip assembly comprises a slide ring comprising an open center, an upper slide surface, an inner slide surface, and a lower slide surface. An upper joint plate is slidably coupled to the upper slide surface and the inner slide surface is configured to couple the fluid-dynamic body. A lower joint plate is slidably coupled to the lower slide surface and the inner slide surface, and is coupled to the upper joint plate through the open center. The lower joint plate is configured to couple to the fluid-dynamic body.

Abstract: An aircraft includes a fuselage and takeoff and landing wings that are extended at takeoff and landing and serve as the main aerodynamic elements producing the lift. The takeoff and landing wings are in a retracted position in cruising flight to attain a minimum possible drag coefficient of the aircraft and, as a result, reduce fuel requirements in the cruising configuration significantly. When retracted, the takeoff and landing wings are integrated compactly into the fuselage surface. The retracted takeoff and landing wings are fixed in position by retracted position locks of the fuselage. A takeoff and landing wing has a turbine blade profile in cross-section. A takeoff and landing wing has longitudinal rows of slots simulating the operation of a slat and a two-slot flap. The slots are closed with shutters on the outer side of the wing.

Abstract: A lift arrangement for an aircraft includes an aircraft fuselage section with an outside, an aerodynamic lift body attached to the aircraft fuselage section and extending from the aircraft fuselage section outwardly, and a pair of movably held add-on bodies arranged upstream of a leading edge of the aerodynamic lift body. The add-on bodies include an aerodynamically effective surface and are equipped with incoming airflow to generate vortices that impinge on the aerodynamic lift body, thus leading to an increase in lift on the aerodynamic lift body. Thus the lift generation on a lift body is effectively influenced, in particular to compensate for loss of lift as a result of icing. The add-on bodies are moveable, and, can be moved to a neutral position in which they do not project into the flow around the aircraft, and are thus not effective from the point of view of fluid dynamics.

Abstract: A device and a related method are disclosed for selectively providing a modified aerodynamic flow over a wing under aerodynamic flight conditions with respect to a respective datum aerodynamic flow over an external wing surface of the wing in the absence of the device under similar aerodynamic flight conditions. The device includes a body configured to be movably mounted to the wing for selective displacement between at least two different positions with respect to the external wing surface and having an external body surface. The device includes a motion inducing arrangement coupled to the body and configured for providing the selective displacement. In each position, the body is in a respective superposed relationship with a respective wing surface portion of the wing external surface and the modified aerodynamic flow includes airflow over the external body surface. A wing and an air vehicle including the device are also disclosed.

Abstract: The present invention relates to a method for actively deforming, by feedback control, an aerodynamic profile comprising an elastic material, applied to a part of the surface of the aerodynamic profile, said elastic material being in contact with a fluid flow; said elastic material being able to be deformed by one or more shape memory actuators placed in contact with the elastic material, said actuators being controlled by a computer connected to sensors. This method applies notably to a deformation of an aerofoil of a wing of an aircraft in flight, notably subsonic.

Abstract: The movable surfaces affecting the camber of a wing are dynamically adjusted to optimize wing camber for optimum lift/drag ratios under changing conditions during a given flight phase. In a preferred embodiment, an add-on dynamic adjustment control module provides command signals for optimum positioning of trailing edge movable surfaces, i.e., inboard flaps, outboard flaps, ailerons, and flaperons, which are used in place of the predetermined positions of the standard flight control system. The dynamic adjustment control module utilizes inputs of changing aircraft conditions such as altitude, Mach number, weight, center of gravity (CG), vertical speed and flight phase. The dynamic adjustment control module's commands for repositioning the movable surfaces of the wing are transmitted through the standard flight control system to actuators for moving the flight control surfaces.

Abstract: An apparatus comprises a structure having a first side, a second side substantially opposite to the first side, a flexible skin, and a plurality of deformable assemblies. The flexible skin is attached to the first side and the second side of the structure. The plurality of deformable assemblies is moveably connected to the structure, in which each deformable assembly in the plurality of deformable assemblies has a vertex and a base. The each deformable assembly in the plurality of deformable assemblies has a height that is capable of changing to change a shape of the structure and a shape of the flexible skin.

Abstract: This invention relates to a propulsive unit for an aircraft, comprising: a nacelle which defines a duct for channeling an airflow when in use and which provides an outwardly facing surface of the propulsive unit, the outwardly facing surface having an aerodynamic shape; a fan unit for accelerating the airflow within the duct when in use; wherein the duct has an inlet and an outlet and the nacelle is operable to adjust the either or both of the area of the inlet and outlet whilst substantially retaining the aerodynamic shape of the outwardly facing surface.

Abstract: The invention relates to a wing for generating lift and comprises a trailing edge, a leading edge, an inner end, an outer end, a top surface and a bottom surface. The wing comprises an aerofoil with a chord line and a span direction. The leading edge comprises a kink between the inner end and the outer end. The leading edge comprises a forward sweep part between the inner end and the kink extending towards the kink presenting an angle relative to the span direction. The leading edge comprises a backward sweep part between the kink and the outer end extending from the kink presenting an angle relative to the span direction. The top surface comprises a flow control means for controlling the lift at least partly located between a leading edge part between the kink and the outer end and located between the leading edge and the trailing edge.

Abstract: The invention pertains to a flow body with a flow surface section that extends in a flow body wingspan direction and a flow body chord direction and with a plurality of fluid lines that lead into the flow surface section and respectively form an opening therein, as well as to a method for taking in and/or blowing out fluid through at least one fluid line that leads into a flow surface section of a flow body and respectively forms an opening therein.

Abstract: A wing assembly has a wing and one or more no-bias laminar flow oval diskettes that are fixed on a support structure along the C/L (center of lift) of an airfoil, of an aircraft wing. The benefit of an oval diskette with laminar flow is that it has no speed limitations and it allows an aircraft to clime at a speed that matches its Ground Effect Lift speed which is a 25% performance increase and a 40% reduction in vortex drag with a increase stability that eliminates inertia coupling of high-speed airfoils.

Abstract: A structure includes a polymer structural member, which may include a shape memory polymer material, that can change its size and/or shape. An electromagnetic source is used to impose an electric field or a magnetic field on the polymer structural material, in order to control the shape of the material. The force may be used to change the shape of the material and/or to maintain the shape of the material while it is under load. The polymer material may be a solid material, may be a foam, and/or may include a gel. A shape memory polymer material may have mixed in it particles that are acted upon by the electromagnetic field. The structure may be used in any of a variety of devices where shape change (morphing), especially under loading, is desired.

Abstract: A method and apparatus for an adaptive aerostructure is presented that relies on certified aerospace materials and can therefore be applied in conventional passenger aircraft. This structure consists of a honeycomb material which cells extend over a significant length perpendicular to the plane of the cells. Each of the cells contains an inelastic pouch (or bladder) that forms a circular tube when the cell forms a perfect hexagon. By changing the cell differential pressure (CDP) the stiffness of the honeycomb can be altered. Using an external force or the elastic force within the honeycomb material, the honeycomb can be deformed such that the cells deviate from their perfect-hexagonal shape. It can be shown that by increasing the CDP, the structure eventually returns to a perfect hexagon. By doing so, a fully embedded pneumatic actuator is created that can perform work and substitute conventional low-bandwidth flight control actuators.

Abstract: A wing, such as a wing for an unmanned aerial vehicle (UAV), includes a beam or box that can be selectively expanded from a collapsed condition, to increase the thickness of the wing. The beam may include a pair of plates that are close together when the beam is in a collapsed condition, and separate from one another to put the beam in an expanded condition. The plates may be substantially parallel to each other, and may have shape memory foam and/or resilient devices, such as coil springs, between them, in order to provide a force to separate the plates before, during, and/or after deployment of the wing. The expandable/collapsible beam may have a lock mechanism to lock it into place when the beam is in an expanded condition.

Abstract: Systems and methods to provide distributed flow control actuation to manage the behavior of a global flow field, are provided. An example of a system can include an aerodynamic structure having an outer surface, and an array of a plurality of effectors connected to the outer surface of the aerodynamic structure to be in fluid contact with a flowing fluid when operationally flowing, to induce controlled, globally distributed disturbances at a viscous wall sublayer of a turbulent boundary layer of the flowing fluid when operationally flowing and to manipulate fluid behavior of the flowing fluid to thereby substantially reduce pressure loss associated with incipient separation of the fluid flow from portions of the aerodynamic structure.

Abstract: A vehicle control method (and concomitant control structure) comprising deploying an electrolaminate affixed to a substrate and using the combination to control motion of the vehicle.

Abstract: Link mechanisms, including Stephenson II link mechanisms for multi-position flaps and associated systems and methods are disclosed. A system in accordance with a particular embodiment includes an airfoil having an external flow surface with an upper portion and a lower portion, and with the airfoil forming a base link. The system further includes a six-bar linkage coupled to the airfoil and having a Stephenson II configuration, including a binary second link pivotably connected to the airfoil, a ternary third link pivotably connected to the second link, a binary fourth link pivotably connected to the third link, a ternary fifth link pivotably connected to the airfoil and the fourth link, and a binary sixth link pivotably connected to the third link and the fifth link. The system can further include a deployable leading edge panel carried by the linkage, with the leading edge panel being movable via the linkage between a stowed position and at least one deployed position.

Abstract: The invention relates to an elongated, torsion-deformable aerodynamic element, in which the upper surface (2) is continuous while the lower surface (3) comprises a longitudinal slot (6) in the direction of the span and in the vicinity of the leading edge (4). Furthermore, an actuator device (14) inside said aerodynamic element is capable of sliding the edges (6A and 6R) of the slot (6) relative to each other.

Abstract: An aircraft having a high lift system, including a control computer, high lift bodies on each wing, a drive coupled to these, an activation device connected to the drive via an analog connection, an input device, and sensors detecting a state of the high lift bodies connected via analog lines to the activation device. The input device connects via a digital connection to the activation device for transmitting commands for adjusting the high lift bodies. The activation device is installed in the payload area of the fuselage and in an area extending from a location spaced from the front of the wingbox by a distance of one third of the fuselage length extending from there to the aircraft's tip, as far as a location spaced from the rear of the wingbox by a distance of one third of the fuselage length extending from there to the aircraft's tail end.

Abstract: A solid-fuel pellet thrust and control actuation system (PT-CAS) provides command authority for maneuvering flight vehicles over subsonic and supersonic speeds and within the atmosphere and exo-atmosphere. The PT-CAS includes a chamber or solid-fuel pellets that are ignited to expel gas through a throat. The expelled gas is directed at supersonic vehicle speeds in atmosphere to a cavity between an aero control surface and the airframe to pressurize the cavity and deploy the surface or at subsonic speeds in atmosphere or any speed in exo-atmosphere allowed to flow out a through-hole in the surface where the throat and through-hole provide a virtual converging/diverging nozzle to produce a supersonic divert thrust. A pellet and control actuation system (P-CAS) without the through-hole provides command authority at supersonic speeds in atmosphere.

Abstract: An aerofoil member is described which provides for a ‘smart Core’and flexible skin. The core comprises sheet material elements forming adjoining cells. The length of the elements can be changed, for example, using the piezo-electric effect, to alter the cross-sectional shape of the aerofoil without changing the peripheral length. Thus, the shape of the aerofoil may be changed to suit different flight conditions, or to mimic the effect of control surfaces.

Abstract: An aircraft including: a fuselage and two wings to which engine nacelles are attached and that are each connected laterally to the fuselage, one on each side thereof, by a central fairing. The central fairing includes, facing each wing, two opposed surfaces connected one to a suction face side and the other to a pressure face side of the wing and that extend longitudinally along the fuselage. At least one of the two surfaces includes at least one local geometric deformation configured to generate lateral aerodynamic disturbances on the central fairing toward the wing to control the flow of air over the wing.

Abstract: A casing for a lifting aid for an aircraft, comprising at least one strake which extends essentially in a protruding manner in the direction of flight in relation to an outer surface of the casing. An aircraft comprising a lifting aid and said type of casing.

Abstract: An airplane wing configuration includes a first wing positioned above and forward of a second wing on an airplane fuselage. The first wing is operable to direct airflow over an upper surface of the second wing, whereby the first and second wings are capable of generating greater lift than a sum of their individual lifts. The first wing may include an adjustable wing flap that redirects airflow over the upper surface of the second wing, and the second wing may include a rotatable portion that pivots to vary the angle of attack of the second wing independent of the first wing.

Abstract: An aircraft assembly comprising: a pair of covers; a spar web extending between the covers in a thickness direction, the spar web having a length which extends in a span-wise direction; and a container which extends from the spar web and houses at least part of a system component. The container comprises first and second side walls which are spaced apart from each other across the spar web in the thickness direction, and inboard and outboard walls which are spaced apart from each other along the spar web in the span-wise direction. The spar web and at least part of the container are integrally formed as a single piece.

Abstract: A propulsion system for an aircraft includes an airfoil, an engine having an engine cowling carried by the airfoil and configured to produce exhaust gases that are predominantly directed toward an aft end of the airfoil by the engine cowling as engine exhaust, a propulsion flap carried by the airfoil and disposed aft of the engine cowling and a plurality of exhaust ejection orifices provided in the propulsion flap and adapted to receive at least a portion of the exhaust gases from the engine cowling.