Needed something a little different after the last model and a launch powered by a water-jet drive looked interesting. First plan was to use a Graupner unit but they seem to be unobtainable, maybe never to be available again?
Someone then suggested the NQD units and an internet search was quickly undertaken. They seemed to be promising and a site was found that would sell a pair of units at a reasonable price. My immediate thoughts on receiving them was how similar to the Graupner units they were but being made for smaller motors. This would limit my model to a modest size and weight.
Designing the hull was not easy as the planing shape had to have a flat area for the unit to fit through. In the end a hull shape that did not look too bad was created using balsa and plywood. The final appearance was based on a fast launch that might be used by Mediterranean or Cribbean Coast Guard services. It was 24 inches long with a beam of 4 inches and ,with a six cell Nimh battery pack, weighed in at eaxctlt 2 pounds.
Static tests in the garden pond revealed a heathy reaction to full power and a current of 4-5 Amps. Sailing test were something of an anticlimax with excellent handling at all speeds. Without any rudder or keel, I had feared that the model would show wandering tendencies, infact it would run quite straight until the nozzle was moved but on centering the transmitter stick it returns to a straight heading. The heel in turns is quite noticable but never becomes dangerous. Top speed is about 6 feet/sec, which isn't bad considering the modest input power.
The only drawback is the absence of any astern thrust, lots of astern noise but no sign of moment. The NQD unit being supplied with no reversing bucket unlike the Graupner units. This is something that still catches me out when bringing the model back for recovery!
Plans drawn up and text ready for final checking before submitting to the Editor of Model Boats
Glynn Guest
