THEORY OF CHANNEL WING AIRCRAFT: SPEED OF AIR

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The “Lifting Force”

In front of the propeller the available “Lifting force” is determined by the mean airflow velocity (relative to the inner surface). A correctly designed propeller provides high-velocity air through a channel and a denser than normal air mass with propulsive efficiency behind. However, some Thrust force will always be exerted normal to the propeller disk. This is a secondary effect of the power applied to “lift” rather than “push” the aircraft, and it provides a satisfactory method for directional control in the longitudinal plane by forming a resultant force with a “Lifting force”.

The resultant of the “Lifting force” and the residual Thrust is always of greater magnitude than the basic Thrust force of the propeller when out of the channel. At low aircraft velocities (relative to the ground or the air envelope) the resultant is in excess of 45 degrees. Thus a “hovering” condition can be reached when the resultant force equals the weight, the power applied being proportionate to the rate of Thrust dissipation. In this condition, with other forces remaining constant, rearward flight results whether from an increase of power or an increase in angle of attack.

As the angle of attack decreases the resultant force vectors toward Thrust augmentation and the supporting forces require redistribution to remain aloft. This can be accomplished by the addition of power with a Thrust dissipation or, more simply with existing developments, the establishing of aerodynamic Lift on a supplementing wing or a channel wing with an airfoil section. With the channel wing the “Lifting force” of the velocity differentials across the channel approach “unity” as aerodynamic flight is approached…

The aerodynamic Lift coefficient of a channel wing is always positive with some negative angle of attack. This means that … there is a negative pressure at the advancing edge which tends to nullify the normal compression of air at this point. Thus a velocity increase is permitted for a power application that is not normal in aerodynamic flight… Terminal velocity is not a function of “sonic compressibility” due to this laminar air being displaced during a velocity relationship above “unity” across the channel. Acceleration, however, will vary according to the rate of improvement in propulsive efficiency—once again contingent on propeller design.

It is comprehensible that only a small percentage of the power used in aerodynamic flight is converted into the work of “Lifting”. The greatest percentage of power is used to overcome the “drag” caused by the airplane velocity. On account of its “push” application power must be increased on an exponential curve of the “cube” to provide aerodynamic flight of doubled velocities. The power requirements curve, which does not follow the aerodynamic “cube” scale (in the channel wing), is also flattened toward a straight-line increase because of the unique Lift coefficient of the wing. The “overpower” requirement at the compressibility area is thus also avoided, or rather obviated, for velocity calculation in design in the Channel Wing…

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