Hydrofoil

A hydrofoil or hydrofoil is a high-speed water vehicle that is raised with increasing speed of below hydrofoil while driving. Thus, the hull is clear of the water, the vehicle "flies" over the water surface. Since there is then only a small part of the vehicle ( wings and propellers) below the water surface, displacement and frictional resistance are significantly reduced. Hydrofoils reach thereby speeds up to 48 knots ( about 90 km / h).

In German usage is meant by the term hydrofoil also an enlarged anti-cavitation plate on outboard motors and sterndrives of pleasure boats. The operation is the same as described in the here hydrofoils, however, due to the much smaller size according to casement lower.

History (1900-1934)

The development of hydrofoils began around 1900, although it previously gave to ideas. Shortly after 1900, the Italian airship engineer Enrico Forlanini ( 1848-1930 ) dealt with the development of flying boats. The result was the first operational hydrofoil, built in 1906, as its inventor, he is generally. He crossed so that the Lago Maggiore and reached with his propeller driven hydrofoil a speed of 38 knots (70 km / h). Due to its merits the Milan Linate airport was named after him.

At this time, in March 1906 describing the American hydrofoil pioneer William E. Meacham in a scientific contribution, the basic principle of hydrofoils. Thereupon, the American inventor A. G. Bell employed from 1908 also with this technology and introduced in 1919 after several attempt booting a first usable Hydrofoil ( Bell HD -4) before.

In England, the English shipbuilder John Isaac Thornycroft employed in the context of military applications also using this technology. He had studied at the University of Glasgow to Lord Kelvin and Professor William John Macquorn Rankine and was very successful in the construction and driving of torpedo boats of the Royal Navy. He experimented with the elements of hydrofoils to increase the speed of its torpedo boats.

In Germany, Hanns von Schertel employed since 1919 hydrofoil, his goal was the rapid passenger transport on the water. His biggest success was a demonstration for the Cologne - Düsseldorf German Rhine navigation AG with his eighth attempt boot silver bird. With this boat and seven passengers, he led in April 1934 by a successful demonstration drive from Mainz to Cologne and back. The boat had a capacity of 50 hp and reached a speed of 55 km / h

Use

Hydrofoils are mainly used for military applications, and the carriage of passengers on rivers (Russia), used to transfer between the mainland and islands and between island groups. Thus, for example, the inventor Felix Wankel tested its hydrofoils and his Gleitflächenboot of his Lindauer Development Center of temporarily on Lake Constance. The brothers took over Sachsenbergstraße 1940, a terrain with shipyards in Harburg and built here with Schertel newly developed hydrofoils of different sizes from 5 to 100 tonnes for the navy and the army.

There are also hydrofoils with sail drive (eg Hydroptère or boats of the International Moth Class). The behavior is comparable in principle to a dinghy that rises out of the water while on plane.

Types

There are three different designs of hydrofoil boats, with different methods of buoyancy control:

The head type has never been enforced. The partly- dipped construction, which also inspired hundreds of Soviet ferry and military vehicles have been built, is now increasingly replaced by the more complicated, but more efficient fully immersed construction.

Today hydrofoils are almost exclusively used for the transportation of passengers. Here are mainly American or produced under license in the PRC Boeing hydrofoils to use based on the principle of fully submerged hydrofoil. Also widespread are the Russian and Ukrainian types " Voskhod " and " Colchis " found, based on the principle of the partly submerged hydrofoil. They are characterized by a particularly simple and robust construction.

In military applications hydrofoils have now been almost completely phased out and replaced with simple designed vehicles with greater carrying capacity. Due to the sensitivity of the hydrofoil systems and the inability to operate at low speeds, to hydrofoils have been less useful for military use. The bulged through its high performance type Pegasus class was retired in the early 1990s from the U.S. Navy and scrapped up on a product now used as a museum specimen.

Meanwhile, different designers with hybrid concepts in which conventional hulls were fitted to increase the drive speed with wings occurred. The best-known concept of this kind is Hysucat from South Africa, in which a rigid unregulated wing is mounted on the foredeck between the hulls of a catamaran. It is currently being used successfully in more than twenty new buildings, which increased at a constant engine power their travel speed by more than 15 %. In some T- types, the employment is directly mechanically, the hull is similar to a two-part stepped hull and is equipped with an articulated hinge. If the front part slides open with increasing speed, it pulls the rear fuselage front high and thus provides to the attached wing. Even the fastest wind-powered watercraft, the Hydroptère is a trimaran with type V wings.