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Old 12-17-2015, 02:41 AM   #7 (permalink)
bluebunny
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Quote:
Originally Posted by freebeard View Post
The closest analog I can think of is the Air Curtain BMW, Ford and other use on the front wheel wells.

I suspect you will just move the separation from the top behind the edge to the throat of your converging duct. Suppose you replace the quarter-circular canard with a flat, horizontal plate to maximize the air ingested. Or just trim the curved one back. It need only protrude forward a little more than the half-round.

Edit: OTOH there're also the 'turning vanes' on the front corners of European trucks. They accept the air at right angles to the ambient flow.
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Yes, the extreme is the flat-plate canard in use today by one builder of those big armored trucks! They are likely very low drag canards, and may actually outperform the one I propose! But I suspect even that one may benefit from a curved leading edge, and its greater height will also tend to increase the cross-sectional pressure area?...

The sketch shows both designs for comparison...

The curved slotted canard design takes greater care to accelerate the flow through a true nozzle, but they both are intended to control the boundary layer along the sides of the box...

leading edge slots and slotted flaps are explained in this ancient film from the 30's. the canard slot follows the principle. starts 7:30 into the film...

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