Above-Water Applications of Voith-Schneider Propulsion

The Voith Schneider propulsion system rotates on a vertical-axis and is well-proven in tug boat and ferry boat propulsion. A new-generation Austrian company has advanced that technology to rotate on a transverse-axis above water in aeronautical application, with capability for vertical lift-off. Their technology has possible application in wing-in-ground (WIG) vehicles that require vertical lift-off capability at land-based coastal terminals.

Introduction

The history of transverse-axis machinery in vessel propulsion predates the development of longitudinal-axis propellers. Side-wheel and stern-wheel propulsion technology evolved from waterwheels that had for centuries been installed along rivers to deliver mechanical power and proved quite successful in early riverboat operation. Side-wheel propulsion technology proved to be problematic in ocean operation when waves caused vessels to roll, alternately lifting one of the side-wheels above water and affecting vessel directional control. During the early 20th century, several aircraft developers attempted to adapt transverse-axis technology to airplane propulsion, with limited success.

While inventor Ernst Schneider intended to develop a turbine for hydro-electric power dams, the Voith group sought to adapt Schneider’s concept to operate as a water pump. By 1931, the water pump had been developed into a propulsion system for a ferry vessel that sailed on Lake Constance. During early 1960s, designers developed a horizontal-axis version of the Voith Schneider technology to operate on aircraft. Many decades later in Austria, designers at the Cyclo Tech group in Austria adapted modern, lightweight high-strength material to operate on a transverse-axis, in aeronautical propulsion and with prospects for future success.

Applications Above Water

The original intention by Ernst Schneider was to operate the rotary technology as a turbine. In this modern era, there may actually be potential to adapt Schneider’s concept to operate as a vertical-axis wind turbine, installed above the deck of a boat. The design allows the blades to change angle with respect to direction of fluid flow, in turn reducing the parasitic drag that is inherent in vertical-axis wind turbines. It is a concept that needs to be tested to determine whether is could efficiently activate a marine propulsion system and enable a vessel to sail into a headwind.

The transverse-axis aeronautical propulsion system offers the combination of vertical lift-off, tough-down and propulsion. It has potential application in ground effect vehicles that due to coastal wave conditions at numerous coastal locations internationally, could be designed to touch down on and lift off from land-based coastal terminals. The transverse-axis propulsion is system is compatible with ground effect wings. A forward mounted propulsion system would direct a rearward flow of air to move at low elevation directly under the ground-effect wings. Companion rear propulsion assemblies would provide a greater percentage of forward thrust.

Flying Car

Cyclo Tech of Austria is focused on developing a flying car that uses forward and rear transverse-axis propulsion assemblies based on the Voith Schneider concept adapted to aeronautical service. It is a technology that could ferry small groups of passengers between the deck of a ship anchored offshore and a coastal location, or between a ship sailing parallel to a coastline and a shore-based location. The Cyclo Tech flying car could carry ship pilots to and from the deck of a moving ship during rough sea conditions, when transfer of pilot between small boat and large vessel is problematic.

The inclusion of ground effect wings into the design of the Cyclo Tech flying car would extend its operating range across water, such as carrying passengers to and from the deck of an offshore drilling platform. The vertical lift-off and touch down capability of the Cyclo Tech vehicle enhance its attractiveness as the technology to carry ship pilots to and from the decks of vessels, or personnel to and from the land pad of an offshore platform. There may be a market for large commercial versions of the technology capable of carrying 12-people between land and offshore locations.

Future Development

While Cyclo Tech has undertaken a considerable amount of research and development into adapting the Voith Schneider propulsion system to aeronautical application, their version of the flying is a prototype with much potential for future development. The growth of airline travel at overcrowded airports provides market opportunity for a vehicle with vertical lift-off and touch-down capability, at small terminals that involve limited space. A large-scale wingless version of the technology could carry passengers over short distances across land while a winged, large-scale variant could be developed to travel over extended distances above water a water surface.

There is likely potential to increase the diameter and width of the rotors, with the option of developing a vehicle with 3-pairs and even 4-pairs of rotors spaced along a fuselage that might also include forward and rear ground-effect wings. A ground-effect winged version of the technology might feature partially enclosed rotors with variable area outlet, to increase air exit speed that would in turn increase vehicle travel speed above water. Vectored thrust that redirects the air stream would assure vertical lift-off and touch down at land-based coastal terminals that offer limited space for vehicle acceleration and deceleration.

Conclusion

The work undertaken by Cyclo Tech of Austria has greatly advanced the concept of adapting maritime-based vertical-axis propulsion technology for the combination of transverse-axis lift-off, touch down and propulsion involving aeronautical technology. As a matter of coincidence, their technology also has potential involving maritime vehicles that travel just above the water surface, using ground effect wings. There is much potential to develop the Cyclo Tech concept to ground effect vehicle application, to provide extended operating range and higher speed capability above a water surface, perhaps involving a vehicle built with the combination of forward and rear ground-effect wings.

Ernst Schneider originally envisioned the vertical-axis technology converting energy at a hydro-electric power dam, except staff at Voith envisioned the technology as a water pump with possible vessel propulsive application. The may be potential to develop a vertical-axis wind turbine based on Ernst Schneider’s original concept, for testing on the deck of a wind-powered vessel where the wind turbine drives an underwater propulsion system. So far, people such as New Zealand engineer Jim Bates, Canadian physics professor Brad Blackford and British researcher Peter Worsley have built wind-powered vessels with horizontal-axis wind rotors, that have sailed directly into headwinds.