How It Works-Amazing Vehicles

© Gibbs Spor ts A mphibians Inc

need a lot of water displacement, which

demands a bulk y body that looks odd on the

road. Today’s amphibious cars and ATVs are

built from composite material – a strong and

lightweight blend of plastics and fi bre. These

lighter bodies sit higher in the water and

require less speed to break the plane.

Propulsion is another huge obstacle. Earlier

motorised amphibious vehicles relied on

propellers for thrust. Propeller blades had to be

small in order to ride high enough on the road to

avoid damage, and small propellers provide less

thrust. Modern amphibians have switched to

water jet propulsion systems with no moving

parts outside the craft. Water jets take in water

through a hole in the bottom of the hull and use

power from the engine to turn a centrifugal

pump to build up pressure. The pressurised

water is then forced through a nozzle in the

rear, providing for ward thrust.

The militar y has always been a great

supporter of amphibious vehicles, with landing

craft, troop movers and jeeps playing critical

strategic roles since World War II. With

continued military funding and engineering

breakthroughs, we might see a commercially

viable amphibious car sooner than you think.

The Quadski’s compact water jet

system delivers serious thrust

Jet propulsion up close

Drive shaft

The water jet system is

powered by a dedicated

drive shaft connected to

the BMW engine.

Intake grate

Water feeds into the jet

system through an intake

grate below the surface.

Impeller

Like a propeller, an impeller

is a rotating blade that

builds water pressure

using centrifugal motion.

Pump housing

The closed environment of

the pump housing is key to

building high water pressure.

Propelling nozzle

This nozzle is tapered to a

point. As water exits the jet,

it accelerates across the

nozzle, creating greater

speed and thrust.

Steering nozzle

The Quadski manoeuvres

through the water by

adjusting the direction of

the water jet with a

swivelling steering nozzle.

Reversing bucket

Reverse is easy with a water

jet system. By placing a cap

over the steering nozzle, the

jet is defl ected in the

opposite direction.

The Quadski is an amphibious

transformer, switching from ATV to

jet-ski at the push of a button. The

quick-change act centres on the wheels,

which fully retract in fi ve seconds

thanks to two zippy servomotors. On

land, the Quadski looks and rides

exactly like a quadbike. For mud-

chewing trail rides, the Quadski is

powered by the same 130-kilowatt

(175-horsepower), 1.3-litre motorcycle

engine that supercharges BMW’s

high-performance racing line. For

safet y reasons, the engine is capped at

60 kilowatts (80 horsepower) on land,

reaching a maximum 72 kilometres (45

miles) per hour. But the real magic is

seeing this lightweight ATV move from

land to water. Previous amphibian car

concepts were literally dead in the

water, slogging slow and low. The

Quadski, however, leaps out of the

water using the full 130 kilowatts (175

horsepower) to pump water through its

jet propulsion system. By riding high on

the surface on its fi breglass hull, the

Quadski can match its maximum land

speed on the water.

A quadbike that goes from turf to surf in just fi ve seconds

Gibbs Sports Quadski

DID YOU KNOW? In 2012, DARPA decided to crowdsource a new design for the military’s AAV with a grand prize of $2m (£1.24m)