The Boeing Company

United States of America As Represented by the Secretary of the Air Force

Charles A Grotz

William J Hirt

A STOL aircraft having turbojet or torbofan engines mounted above and forward of the wing whereby the engine exhaust gases flow over and, by the Coanda effect, attach to the upper surfaces of the wing and a downwardly curved extendible flap to produce a downwardly turned exhaust flow having a large vertical component of thrust. Premature separation of the exhaust flow from the wing or flap due to reduced velocity in the boundary layer of the flow, which would result in decreased turning of the exhaust gases and a reduced vertical thrust component, is prevented by a boundary layer scoop extending across the exhaust flow, in an area just prior to where the exhaust flow would separate from the wing or flap, for removing the boundary layer gases and discharging them beneath the wing.

Boundary layer scoop for the enhancement of Coanda effect flow

A method of enhancing Coanda flow attachment over a wing and flap surface of an upper surface blowing aircraft comprising the step of directing the jet exhaust flow or stream toward regions wherein the exhaust flow separates from the wing and flap surface so as to create an outward velocity component which prevents ambient air from flowing in and under the exhaust from the sides of the exhaust flow and causing such separation is disclosed. The method comprises the further step of creating vortices also having outward velocity components on the wing and flap surface. The outward velocity components of the vortices further increases the sidewise velocity component on the wing surface. In addition, the rotational velocity components of the vortices scrub the boundary layer air from the flap surface to further promote flow attachment. Apparatus suitable for carrying out the method and comprising a plurality of airfoil shaped vortex generating vanes located between the engine exhaust and the trailing edge of the flap is also disclosed. The vortex generating vanes direct the exhaust stream toward the separation regions and create the outward velocity component vortices.

Method of and apparatus for enhancing Coanda flow attachment over a wing

A method of controlling flow attachment to the wing and flap surfaces of an upper surface blowing type aircraft by horizontally controlling the divergence of the jet exhaust of the aircraft engines to control the vertical thickness of the exhaust is disclosed. In addition to controlling the thickness of the exhaust, control of the divergent exhaust also provides control over the outward velocity component of the exhaust which further provides control over flow attachment by controlling the flow of ambient air under the jet exhaust. In one form, the apparatus of the invention comprises one or more side panels, located at the end of the engine exhaust nozzle, adjacent to the surface of the wing. When the panels are moved outwardly, openings are formed which allow the exhaust to horizontally diverge. When the panels are moved inwardly, the openings are closed and the exhaust is no longer diverted and thinned. In an alternate form, the apparatus of the invention comprises movable vanes mounted on the wing, slightly rearwardly of the end of the exhaust nozzle. The vanes are movable so as to either divert the exhaust outwardly and thin it, or to be aligned with the exhaust stream to have little or no effect on the exhaust whereby it remains unthinned.

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Seattle, WA, United States of America

Charles A Grotz