Experimental Craft & Innovative Hull Forms

Development Projects (Experimental Wing System):
HIGH SPEED SAILING CRAFT:
Background

 

Watercraft whose means of developing dynamic lift is entirely from hydrofoils and/or planing elements develop a certain amount of drag from the structure that keeps all of these water and airfoils positioned and linked. Furthermore, the performance of a hydrofoil deteriorates near the surface of the water. More extensive use of airfoil surfaces offers a possible solution. Use of airfoil surfaces with adequate means of control and adjustment to provide vertical lift avoids compromising lift at high speeds when ventilation or cavitation of the hydrofoils occurs. Use of super cavitating profiles on less critical hydrofoil surfaces minimizes the degradation of side force at high speeds without interfering with the development of vertical lift at low speeds. Where these surfaces have a variable cant relative to the horizontal and can pivot fore and aft relative to the lateral plane, trimming and controlling them to develop vertical lift or horizontal drive is analogous to trimming a windsurfer sail or flying an airplane. Some configurations are designed to provide dynamic stability, thus minimizing the need for ballast.

The experimental wing system consists of three principal configurations for a sailing surface effect craft or low flying boat. The different configurations can be assembled from many of the same parts, hulls, wing elements, and wing sails. The first two configurations are similar in appearance to an aircraft with high dihedral tandem wings at 30 degrees from horizontal for the first configuration (left and above) and 45 degrees for the second (below and below left). The third configuration is a craft similar to a trimaran with tandem lifting horizontal wings for cross arms and wing sails in an A-frame rig, which gives it transverse dynamic stability. (This configuration is shown at left and in the four images at the bottom of this section.)

With all three configurations, narrow hull forms and pivoting trim of all wings about spanwise axes should provide for good performance over a wide range of wind speeds. All of the structural elements of the different craft are useful as lifting or driving surfaces or buoyant elements, thereby minimizing parasitic drag and conflicting forces.

In some configurations, free flight should be possible for brief periods of time or for longer periods in conditions where dynamic soaring is possible. The rig is able to develop vertical lift before necessarily having forward motion. Although some configurations are similar to a windsurfer, their operation is not dependent on the strength of the human operator, so that it has the capacity for power and payload greater than the strength and weight of the operator.

Weight vs Geometry

Small hydrofoils on lateral plane appendages will probably be required for supplementary vertical lift making all three of these configurations hybrid ground effect/ hydrofoil craft. Wing loading that would allow the craft to "fly" entirely on airfoils requires a smaller fuselage and amas than shown above. Such a configuration could be awkward for balance and control. It would also need more "sail area" for performance in light and moderate air. Also because of weight concerns, it may be that a catamaran configuration is best for A-frame rig.

However, for trying out all three basic configurations, it is convenient to stick with the modular system. Furthermore, a combination of hydro and aero lifting surfaces means that as hydrofoil performance becomes degraded from ventilation when the craft gains speed and the foils get closer to the surface, the air foil wings assume more of the load. Thus such craft should have good performance over a wide range of wind speeds. As experience is gained in trimming the craft optimally, size and weight of the structure can be reduced and shapes and configurations modified as needed.

Development Phases and Objectives

a) We have built and sailed all three configurations in the form of a working scale model approximately 1/4 of the size of a preliminary prototype of 24' overall. The model needs refinement and improvement, most immediately a new, longer fuselage or main hull. When it is essentially complete and balanced so that all three configurations can sail themselves on a preset course, we will decide if it is more efficient to test it further with the installation of remote controls, or whether it would be more instructive to work with a manually controlled human scale model.

b) We plan to build a preliminary full size prototype using hulls, wings, etc. already at hand for the purpose of establishing the balance and mechanical performance of the craft. We will start it concurrently with the refining of the scale model so that whichever works most readily will be the one to concentrate on.

c) If the preliminary prototype performs as anticipated, we should be ready to build with carbon fiber and high performance composites a craft that is competitive with other multihulls, windsurfers, hydrofoils, and other high speed sailing craft. We could use such a craft for an attempt on the world speed sailing record, or simply explore its application (or limitations) for sport or passage making.

REFERENCE U.S. Patent Nos. 6,016,759 and 6,216,621

Specific aspects of design and operation are discussed in further detail in the patent disclosure. Please contact Wing Systems for further information.

d) We plan to build a preliminary full size prototype using hulls, wings, etc. already at hand for the purpose of establishing the balance and mechanical performance of the craft. We will start it concurrently with the refining of the scale model so that whichever works most readily will be the one to concentrate on.

Earlier Experiments

Surface watercraft that explores the transition between Hydrfoil and planing lift ...
One development of this form was a successful tunnel hull windsurfing "long board".
REFERENCE: U.S. Patent No. 3,742,887