In the mid 80-ies on television in many countries was widely advertised a small, high-speed, extremely maneuverable motorized vessels under the General title of “jet”: “jet-ski”, “waterbot”, “jet ski”. They immediately won the hearts of fans of water sports, surpassing lovers, windsurfers, water skiing and certain types of water-motor sports.
However, to repeat the design of the watercraft in the home due to the high power requirements-rotor vessels (at least 35 — 40 HP) and playback complexity of hydrodynamic surfaces is difficult. Those who had that idea, better to turn to more simple designs. For example, to read aquarelle in No. 6 of the journal “modelist-Konstruktor” for 1991. If for some reasons this scheme is not suitable, you can try to build a machine below. It consists of a frame, two pairs (front and rear) floats, windshield fairing, engine and steering gear.
Materials you need: a foam of any brand (better packaging), some plywood, old skis, a few steel pipes of any motorcycle or moped engine, epoxy (3 — 4 years), fiberglass (4 — 5 m2), tools, and… patience.
On a flat surface (floor) must depict the design of the watercraft in two projections (scale 1:1) and it is pre-cut material (pipe and foam).
Floats require in the manufacture of special attention. Make them out of foam bricks, plywood root ribs and the force of fastening elements by sequential Assembly and gluing. Then with a hacksaw and sand bars brought to the desired shape, hang tissue paper and put in one or two layers of fiberglass, impregnated with epoxy glue (the bottom to the cheekbones, three or four layers). Attach the floats to the frame with cross beams made from skis (we used polyplastics) and dural reinforced bottom shelves. Such beams reduce shock loads when driving. With insufficient strength, or a large loading of the ships should be changed for a metal one.
Frame welded steel seamless pipe (0 70 mm) gas-shielded and reinforce cross rails. In the absence of pipes of the required size you can use small diameter pipe (30 — 40 mm), only in this case the design of the power rack have to do a spatial that will complicate the job.
1 — float front, 2 — front fairing, 3 — device, power steering, 4 — tank, 5 — jet, 6 — seat, 7 — frame, 8 — floats back, 9 — variant for installation of outboard engine, 10 — exhaust pipe, 11 is a shaft, 12, 13 — beams of cross. 14 — coating glass cloth, 15 — rib float root (plywood, s5…6), 16 filler (sticks foam), 17, 18 — fasteners float power (plywood. s5…6).
1 — lining (St3 sheet s3), 2 — bearing mounting of the front floats (St3, pipe Ø32), 3 — step (D16T, sheet, s2,5), 4, 5, 6 — the mounting brackets of the rear floats (St3 sheet s3), 7 — frame parts (45 steel, pipe Ø 70), 8.11 — scarves (St3 sheet s3), 9 bolts M8 (6 PCs), 10 — beam of fastening of a lateral rear floats (shown schematically), 12 — panel mounting pegs (St3 sheet s3).
The site of attachment of the front floats:
1 — bottom shelf beams (D16T, sheet s2,2), 2 — top shelf beams (ski), 3 — M4 screw, 4 — pad(D16T, sheet, s2) 5 bracket (D16T, area 80x80x2,5), 6 — strengthening float (plywood, s5…6).
1 — bolt M5, 2 — plug (D16, pipe Ø32), 3 — rudder (D16T, sheet s2,2).
The steering device can be installed under the stern of the watercraft in the classic version either, as we did, using the bike’s details, directly on the same shaft with the steering column that much easier. However, with the greatly increased effort on the steering wheel. The shape of the outline of the rudder is usually chosen close to the square. However, to control the device and feet, just as they do in Speedway or road racing motorcycles.
Engine, and it can be almost anywhere (even from Puscuta, but with a capacity of no more than 18 HP), fitted in the bottom of the frame near the feet of the driver. The screw drive is via a shaft connected to the engine by bevel gearing. You can use any other programs, it is important that the screw shaft rotates no faster than 3000 rpm. the petrol Tank and other auxiliary elements of the engine will fit from an old motorcycle or moped. Attachment points to the frame for different engines (for example, PD-8M, W-62) pick up on the place, but not less than three points. The best solution would be to use elastic fastening blocks-shock absorbers with rubber-metal strips.
Exhaust pipe a on the basis of convenience and safety, isolating and securing it to the frame with clips. The thermal insulation includes asbestos cloth, three or four layers of stalloreggi and tin casing. But there is a simpler way to unsubscribe from the exhaust, if you have a cooling exhaust pipe seawater. In addition, the supply of water under the cooling will significantly reduce the noise level, especially in two-stroke engines.
Also suitable for jet ski standard outboards of the “Breeze”, “salute”, it is only necessary to modify the aft part of the frame for mounting the engine using the remote control.
However, if there is no engine, nothing, the design of the jet ski is easy to turn in a pedal boat, sailing trimaran, or Buer, and a small weight (about 28 — 36 kgs) makes it easy to transport it by any transport.
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