AP1-88
In English, the term means something like “a vessel that hovers in the air” – and that’s exactly what the machine does. “These are vehicles that, instead of resting on the ground, float on a mattress of pressurized air”, says naval engineer Kazuo Nishimoto, from USP. This mattress is constantly renewed by huge fans and contained by a kind of flexible skirt. Another engine – propeller or jet – provides the horizontal propulsion. Because it is actually in the air, the hovercraft glides smoothly over any surface (water, earth, snow or quicksand) at speeds of up to 150 km/h. The concept is old, but it was not until 1959 that the Englishman Christopher Cockerell managed to build the first hovercraft that really worked, for which he received the title of Sir. Today, there are hovercrafts of all types and sizes, used for military, civil and commercial purposes. The Traffic Engineering Company (CET) of São Paulo, for example, has two units to navigate along the Marginal Tietê in times of flooding.
Hovercrafts are not more common only due to the high cost and energy consumption, since a third of the engine power is used only in its support. Another problem is the noise of the fans and the air escaping under the skirt.
FLIGHT DECK
In it are the pilot and his crew, plus all the controls of the vehicle. At the top, a radio antenna is usually installed.
FLEXIBLE SKIRT
Made of rubber similar to that of car tires, it both contains air and absorbs impacts caused by irregularities in the ground. When the vehicle is in operation, the skirt inflates at the top and hangs down at the bottom, from which a constant flow of air escapes.
CENTRIFUGAL FANS
They suck in air and force it down into the compartment formed by the skirt. The pressure thus created forces the vehicle upwards and keeps it afloat. On the AP1-88, there are 12 fans distributed throughout the vehicle
PROPELLER PROPELLERS
Some hovercrafts have rotating propellers, so you can change the vehicle’s direction. In this, they are fixed: those who direct the impulse are the rudder blades located behind the propellers. The rudder is also assisted by the rotating thrusters.
ENGINES
This hovercraft has four diesel engines. Two of them drive the rear propellers, for horizontal propulsion; two others take care of the centrifugal fans, which provide the vertical support
SWIVEL THROTTLES
Attached directly to the air cushion supporting the vehicle, these devices can rotate at the pilot’s command and release compressed air to help steer the hovercraft.