Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
ALTITUDE CONTROL APPAP~ATUS FOR GROUND EFFECT WINGED VEHICLE
BACKGROUND OF THE INVENTION
This invention relates to an altitude control apparatus for
a winged vehicle which travels in ground effect (ground-
effect winged vehicle). More particularly, this invention
relates to an altitude control apparatus for such winged
vehicle which flies at a very low altitude utilizing the
ground effect produced between its fuselage and wings and
the water surface, and said apparatus making it possible to
categorize such winged vehicle into a vessel according to
the related laws and regulations in Japan.
Various types of transportation means besides typical
ground transportation means have been in use for
transportation of people and goods, such as water
transportation means including various types of vessels and
air transportation means including aircraft (airplane),
helicopters and airships have also been in service. The
water and air transportation means play very important
roles in connecting the main land with remote islands in a
country like Japan which is surrounded by seas.
It is well known that a large vessel can transport people
and goods in large numbers or quantities at a time, but
cannot travel fast enough. As a solution to this
shortcoming, there have been made various proposals, such
as utilizing a jet propulsion as the vessel's propulsion
mechanism in place of the conventional propeller
propulsion, providing external rotors or designing a
catamaran type vessel structure for overcoming wave drag.
Even such improved vessels travel still far slower than
aircraft.
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On the other hand, aircraft, though very fast, are
significantly restrictive in transporting people and goods
in large numbers or quantities. In this respect, large
airplanes have been designed for such mass transportation
purpose and many are already in service. Such large
airplanes, however, are generally difficult to design and
require a high fuel consumption, and moreover, they are
subject to safety law restrictions by far severer than
those on vessels due to their nature to fly at a high
altitude.
Proposals have been made in various fields to realize a new
transportation means which satisfies both of the advantages
of the mass transportation capacity of vessels and the
high-speed mobility of aircraft. In these proposals, there
is included the known technique which is generally called
"air-cushion machine". This technique utilizes a high-
pressure air cushion produced between the fuselage and
wings of an aircraft and the ground or water surface when
the aircraft flies at a very low altitude, and this effect
is referred to as "ground effect". While such ground-
effect winged vehicle is generally used mainly to fly at a
very low altitude above the water surface, such as of sea
or lake, the effect nevertheless is customarily called
ground effect and not water effect. The ground effect
winged vehicle is also referred to as "a wing in ground
effect" (hereinafter sometimes abbreviated as WIG).
Vehicles utilizing the aforementioned ground effect,
including WIGs, are called ground effect machines (GEMs) or
aix cushion vehicles (ACVs). The ACVs are classified into
two types: aerostatic system and aerodynamic system. The
former type re~ers to transportation means of so-called
hover craft or air car, in which a high-pressure air is
positively fed into the space defined between the bottom of
the body and the water (ground) surface and surrounded by
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the skirt or side wall of the vehicle thereby to lift the
body slightly above the water surface. On the other hand,
the latter type refers to the WIG itself under discussion,
which flies like an airplane using the lift produced at the
wings when it travels forward and is generally classified
into a ram wing type, a channel flow type and a sea bird
type depending on the configuration.
The WIG uses considerably reduced fuel consumption by the
increased lift produced by the ground effect for the
greatness of its pay load, and can fly at such a low
altitude as to keep a very small distance between the water
surface and the fuselage. These features contribute to
minimizing possible damages caused by any accident, making
the WIG a very safe vehicle. The WIG can therefore serve
as an optimum commuter means under the circumstance where
it is required to transport people and goods in large
numbers or quantities at high speed between the main land
and remote islands as described earlier.
The WIG basically falls under the category of aircraft,
ie.it travels forward floating in the air free from
physical contact with the ground or water surface. The
fuselage and wings are spaced away from the water surface
(ground) only by the distance enough to acquire the
aforementioned ground effect. The Japanese Aviation Act
defines aircraft as "an airplane, a rotary-wing aircraft, a
glider, an airship or other craft that can be used for
aviation as provided by the government ordinance".
Accordingly, the WIG is treated as an aircraft by the
Aviation Act in Japan, so that the qualification for pilots
and Gther requirements for the WIG, such as servicing and
inspection are subject to the same severe requirements as
for aircraft in general and under the strict supervision of
the competent authorities.
As described, due to its legal status as an aircraft, the
WIG faces the legal barrier that prevents it, unlike
vessels, from being easily maneuvered or operated.
On the other hand, the legal restrictions on vessels in
various countries including Japan are significantly lax as
compared with those on aircraft, and the qualifications and
requirements concerning the pilot's licence, servicing and
inspection for the vessels are less strict. If the WIG can
be legally treated as a vessel, it is expected to gain
worldwide popularity as well as in Japan as the afore-
mentioned commuter means or the like.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a
means which has been developed in the light of the
aforementioned points of the WIG being capable of
transporting people and goods in large numbers or
quantities at a high speed and of the restrictions as
provided by the Japanese Aviation Act, and which allows a
WIG to be treated legally as "vessel" by constantly
connecting the fuselage of the vehicle with the water
surface by some physical means and automatically
25 controlling the flight to prevent the vehicle from ~lying
freely above the water surface.
To overcome the above problems and achieve the intended
object, this invention provides an altitude control
apparatus for a ground-effect winged vehicle (WIG) which
travels at a very low altitude above the water surface with
a very small distance therebetween utilizing the ground
effect produced between its fuselage and wings and the
water surface, comprising:
a sensor rendered in contact with the water surface
constantly during its travel, for supplying informa~ion on
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the distance between the water surface and the fuselaye to
a control system of said vehicle; and
a connecting means for mechanically connecting the
sensor to said vehicle,
whereby an elevator under control by a maneuvering
system is operated based on the information from said
sensor on the distance between the water surface and the
fuselage to allow said vehicle to fly maintaining the
distance between the water surface and the fuselage thereof
at a constant level.
As described above, since the present altitude control
apparatus for a ground-effect winged vehicle essentially
has a means for providing mechanical connection between the
vehicle and the water surface, the vehicle is physically
connected constantly to the water surface so that it can
legally be treated, in Japan for example, as "vessel," not
aircraft. Accordingly, the legal regulations on vessels
which are very lax as compared with those on aircraft can
entirely apply to the ground-effect winged vehicle, thus
making it easier to clear the qualifications for pilot and
other conditions, such as servicing and inspection. In
addition, since the present ground-effect winged vehicle
can be used as an optimum commuter means to connect the
main land with remote islands, the present vehicle is
expected to gain worldwide popularity as well as in Japan.
When the altitude of the ground effect winged vehicle
becomes above the predetermined level during its
navigation, a command is sent to the maneuvering system
based on the information from the sensor to allow the
elevators to maintain the fuselage automatically at the
desired altitude. It is therefore possible to control the
navigation of the ground effect winged vehicle very fast at
a speed of 200 to 500 km per hour, regardless of the level
of waves and wave drag.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figs. 1 and 2 schematically illustrate an embodiment of a
ground-effect winged vehicle employing the altitude control
apparatus of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
~ preferred embodiment of the altitude control apparatus
for a ground-effect winged vehicle according to this
invention will now be described referring to the
accompanying drawings. Since the ground-effect winged
vehicle shown with the reference numeral "10" in Fig. 1 is
well known in itself, detailed description therefor will be
omitted. The vehicle 10 has a stretchable multitelescopic
arm 12 incorporated at the bottom of the fuselage, with
part of said arm 12 being obliquely extended downward from
the rear of the fuselage. More specifically, with the
upper end of the arm 12 being secured to a damper mechanism
14 which utilizes hydraulic pressure such as oil pressure,
the arm 12 extends obliquely downward in a damped state and
is retracted to the shortest size as shown in Fig. 2 when
the ground-effect winged vehicle is moored as floating on
the water. As the vehicle 10 is started and lifted up from
2S the water surface by the aforementioned ground effect, the
arm 12 is designed to be automatically stretched obliquely
downward from the rear of the fuselage.
The telescopic arm 12 has a float 16 provided at the other
end, which is intended to float on he water constantly
while the ground-effect winged vehicle 10 is in navigation
or moorage. The float 16 has a sensor 20 housed therein
which detects the distance between the water surface and
the fuselage of the ground-effect winged vehicle 10 and
supply distance information to a maneuvering system 1~
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provided in the winged vehicle 10. Various operational
principles, such as of laser-applied distance measuring
system, ultrasonic system, ultrashort wave system and
capacitance system, can selectively be applied to the
sensor 20 for the distance detection depending on the
specific conflguration. The telescopic arm 12 serving as
the means to mechanically connect the ground-effect winged
vehicle 10 to the water surface may be replaced with a
rewindable wire and the like.
