JET Propulsion Unit
JET propulsion units, also known as water jet systems are primarily used as the power plant on exclusive high-speed motor yachts, ferries, racing boats and other vessels. In principle this propulsion system sucks in water through an opening in the bottom of the boat, accelerates it via an impeller and then forces it out again through an opening in the stern. Newton’s Law, which dictates that every action has an equal and opposite reaction, now takes over; the jet of water pushed out to the rear produces a forwards movement of equal magnitude in the hull. Boats with a JET propulsion system can operate in very shallow waters, as all the parts normally located below the hull, including the propeller, shaft, shaft bracket and rudder, are eliminated. Initial acceleration is also very high, and this is a major advantage in dragster boats. The linear motion of the water jet also eliminates the characteristic torque moment of the conventional boat propeller. However, as the water has to pass through long narrow ducts with a JET propulsion system, there are inevitable friction losses which absorb rather more energy than a conventional power system.
The inlet pipe and outlet nozzle are manufactured from high-strength pressure cast aluminium and the drive shaft is ballraced. The inlet grille, impeller, guide vanes, control nozzle and reversing flap are of glass reinforced plastic.
The JET propulsion unit 5 is ideal for internal combustion engines, as the water jet can be diverted for reversing, i.e.it is not necessary to reverse the direction of rotation of the shaft. The duct includes an integral water cooling take-off point. Suitable for motors of 15 to 30 cc capacity and electric motors rated at 700 Watts or more. We recommend servos rated at 5kg/cm minimum to control the system.
Specification
Length approx 238mm
Width approx 58mm
Height approx 70mm
Flange approx 48mm
Shaft approx 6mm
Weight approx 500g
Motors
15/30cc gas engines similar to ZENOAH-G 230
700 watt or more electric motors 36-40 740~1000Kv