|The Ground Effect Craft Hoverwing|
The "Versuchsanstalt für Binnenschiffbau (VBD, now DST)", an associated institute of the Universität Duisburg-Essen, location Duisburg, is working together with "Fischer Flugmechanik" on the research project "Technische Entwicklung von Bodeneffektfahrzeugen (TEBEF) - Technical Development of Ground Effect Crafts. This project is funded by the German ministry for education, science, research and technology (bmb+f). Within this work on the VBD has taken over the construction of the two-seated experimental craft Hoverwing. The first tests in the year 1997 were successful - after the maiden flight at 7. May 1997 on the Baldeneysee the flight tests were continued at the island Rügen (Baltic Sea) and on the Ijsselmeer (Netherlands) and the potential of the craft has been proved. In 1998 and 1999 the flight tests werre continued on the Ijsselmeer.
What is the Ground Effect ?
An airplane running at constant speed has a lift which ist independent from the height of the flight. When coming closer to the ground - starting at a region of approximately a wingspan - the lift increases considerably with decreasing height. Because the resistance is nearly constant, the glide number, which gives the relation of lift to drag, increases. In the last consequence the economy of the craft is improved by the potential of carrying a greater amount of cargo in comparison to an airplane in free flight.
Technical features of the Hoverwing
The ground effect technology has been developed since some decades (e.g. the russian Ekranoplans), but the problem was always to overcome the resistance in water during the take off phase. By the fact, that the density of the water is 800 times higher than the air, the power to accelerate until the take off speed is reached is about 2-3 time higher than the power demand for the flight itself. This problem inhibited an economic use of waterbound ground effect crafts.
With the Hoverwing the partner "Fischer Flugmechanik" developed a new concept for the reduction of the take off resistance. The craft is designed as a catamaran, equipped with a static air cushion between the two hulls as it is known from the so called surface effect ships (SES). The air to inflate the cushion is taken from a bypass of the propeller slipstream. By that the air cushion takes approximately 80% of the total weight and so the hydrodynamic resistance of the two floats is reduced significantly. When the take off speed of 80 km/h (for the experimental craft) is reached the aerodynamic lift of the wings with their special profiles is sufficient to raise the craft out of the water and it "flies" with a speed between 100 and 120 km/h.
The ground effect crafts are classified as a ship, because with its limited power installed it can be used only in the grond effect. This has the consequence, that in comparison with aircrafts considerable reductions in the choice of materials, construction methods and admissions are possible - another positive aspect, because the production costs can be kept much lower than for standard aircrafts.
The existing two-seater is a pure experimental craft designed to investigate the technology and to develop it further on. Economic sizes of grond effect crafts using the Hoverwing-Technology are featuring 8, 15, 30 up to 80 seats, dependant of the type of use and the area of operation. The biggest version of the Hoverwing with a speed of 180 km/h is considerably faster than a ship, but much cheaper in construction and operation than an airplane with the same capacity. This gap in the market - cheap and fast transport of passengers cannot be covered by any existing craft and it is a realistic market chance for the Hoverwing Technology.
Press release (Binnenschiffahrt März 2000)
Foto: A. Gronarz
|"2 Asse und ein König" - German High-Tech as Background
In the beginning of February the
german tv-station ZDF broadcasted a mini-series with Heinz Hoenig, Heiner Lauterbach as
well as the recently deceased Martin Benrath acting in the main parts. In this mixture of
crime film, family drama and love story one of the "2 aces" had developed a
ground effect craft. This aircraft/ship is really existent:
Invented by Hanno Fischer, built by the Versuchsanstalt für Binnenschiffbau Duisburg and supported by the german research ministry bmb+f the WIG-craft "Hoverwing" has been successfully tested during the last years and has flown more than 2000 km without any problems.