Cul de canard Cul de canard Cul de canard (CDC) (French for "duck bottom") are the feathers from the back of a duck directly around the preen gland (uropygial gland); they are very buoyant due to preen oil produced by the preen gland. They are used when tying dry flies for fly fishing. They owe their buoyancy to their proximity to the ducks preen gland which secretes an oil distributed by the duck as a cleaning and waterproofing measure. It is unnecessary for the angler to add additional oil by way of floatant. Flies incorporating CDC are easy to dress requiring no floatant
Canard (aeronautics) Viggen has flaps on the canard surface which were deployed simultaneously to cancel out the change in trim. The Beech Starship uses variable-sweep foreplanes to trim the position of the lift force. When the main wing is most loaded, at takeoff, to rotate the nose up a conventional tailplane typically pushes down while a foreplane lifts up. In order to maintain trim the main wing on a canard design must therefore be located further aft relative to the centre of gravity than on the equivalent conventional design. In the close-coupled delta wing canard, the foreplane is located just above and