|Sep 17, 2010, 06:00 PM|
Coanda Channel wing
Willard Custer was a brilliant inventor, his ideas for vaccuum creating lifting surfaces called channel wings have gone almost forgotten. The basis, is that a propeller is mounted at the front of a wing, in a U shaped area, within a conventional wing and tail design. The velocity of the air produced from the propeller, speeds up the air, decreases the pressure on the U shaped wing area and pulls that section upward. Lift is created, not just forwarding tractor propeller force as per usual.
More about Custer and his experiments here: http://www.angelfire.com/va3/bythefire/concept1.html
Henri Coanda was a Romanian inventor of the early to mid 20th century. His Coanda effect is readily seen if placing the back of a spoon near to running water from a tap. The water will bend around the spoon back and actually run a different course afterward. The mounting of engines, such as on the Boeing YC-14 based design I made a few months ago, proved, to me at least, that these Coanda effect forces were highly viable for micro aircraft too.
More about Henri Coanda here: http://en.wikipedia.org/wiki/Henri_Coand%C4%83
Original YC-14 experiment here, as the project called 'Onree': http://www.rcgroups.com/forums/membe...=235502&page=9
Wiki for the Boeing YC-14: http://en.wikipedia.org/wiki/Boeing_YC-14
So, where is this leading to ?
The idea, is to create a livingroom or backyard flyer, that utilises both men's ideas.
The aircraft will be powered by 2 motors, be of a high wing traditional layout and feature Custer channel wings that then send the air downward with the Coanda effect.
The motors must be light and powerful, the receiver and lipo to be placed as low as possible.
Less thrust will be needed to keep the aircraft aloft. This equates to less wing area being needed than conventional designs. Much of the lift will be created with the channel wings and, with little in the way of Reynolds numbers to give more lift from external wing area, more would equate as drag, not lift.
The wingspan can probably be lessened, with the lifting force being increased.
Differential motor thrust may well be the method used for directional control. However, 2 powered motors of the same speed and a rudder assembly would be the preference.
AUW is expected to be under 6 grams if possible.
Wing shape will be of high mounting design, such that the motor channels will be in the middle of the fuselage height. Requiring an undercambered principle for the basis of shape, those traits will also be of advantage to such an aircraft.
12 degrees dihedral.
Forward swept wings.
Here are some unfortunately crude drawings and a pic of the original wing air movement technique on Onree. Also pic of a YC-14, showing the Coanda effect utilised in the positioning of the engines.
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