The revival of interest in cars with a “screw” propellers as we have in the country and abroad accounted for 60 years. It is a all-terrain designs, applicable not only in WINTER but also in other severe road conditions. Various experimental snegohodnye machines, designed specifically for use on boggy terrain, was established in the United States, England, and Japan.
In our country large-scale research work, including the theory of screw propulsion, have done laboratory trails of the cars of the Gorky Polytechnic Institute named after A. A. Zhdanov. Under the leadership of candidate of technical Sciences, associate Professor S. V. Rukavishnikov was developed by a series of light screw machines (GPI-16P, GPI-16ВА, GPI-16ВС and GPI-0.5), the tests which confirmed the assumption about the prospects of applying the “rotary screw” for propulsion of the snowmobile and identified a number of advantages of these propulsion: higher efficiency, increased durability and reliability, higher traction qualities, less weight and simplicity of design.
“Motbob” — legko-screw machine.
Tractor “Fordson” on the worm reels.
Test easy snegohodnomu machine GPI-16P engine “IZH-the planet” with a capacity of 12 HP showed that the machine moves steadily through the snow to a depth of from 200 to 800 mm, readily passes the sastrugi height up to 400 mm. Snegohod has screw drums with a Cylinder diameter of 300 mm and a step helix hooks 840 mm, which corresponds to the lead angle of helix hook 42°. The length of the drum, including front and rear tapered sections — 1650 mm, number of turns 3 and a height of 50 mm. of hooks Hooks made in the form of a trapezoid with base 35 mm and apex angle of 20°.
In tests, comparisons were made with half-track, GPI-15, which had the same weight and power characteristics: both machines showed the same results for the measured parameters. In the conclusions of the testing indicated that the use of spiral drums with the angle of the helical line of hooks 42° it is possible for the snowmobile, but preferably reducing the angle that will increase the pull of the clutch. It was also noted that lateral movement while driving — the most significant drawback mintohotel machine. A necessary device that stabilizes a linear movement, especially on uneven road.
On the lateral displacements of the screw drums has long been known. The engineer A. A. Krzywicki wrote about this in the book “Mechanical means of movement in the snow”, published in 1926. And even then recommended the limit screws jutting out at the sides in the snow glides, stabilizing movement and withstand lateral forces exerted on the helical rib of the drums.
Lab created machine GPI-0,5, released a small batch was used in the winter in Kamchatka to bypass power lines where replaced used to this powerful tracked vehicle GAZ-71.
Ski-helix snowmobile GPI-0,5 consists of body, engine, powertrain (powertrain), chassis, steering and power systems engine and electrical equipment. Body — all-metal, welded, outdoor, designed to carry 2-3 people. It is the main carrier element of the structure of the snowmobile. Front bonnet under which the engine is placed, is made hinged for easy service of engine in exploitation.
The scheme of education on the screw of the power P2, of the bias drum out of the way:
R — resultant force, perpendicular to the working plane, screw cutting hook, P1 — force of thrust, α is the angle of the working plane of the propeller relative to the plane of rotation.
Diagram of the lateral limits of the auger stabilizing runners:
1 — anti-roll runner, 2 — the case of a snowmobile, 3 — screw drum screw.
Motorcycle engine “IZH-Plaketa” provided with forced cooling. When the engine rpm 3200-3500 rpm it develops the capacity of 15,5 HP Power transmission includes a chain of transmission on the clutch and transmission made in unit with the engine, from the gearbox — on gearbox and side — from the main shaft on the bevel gearbox drive propulsion. On the main shaft planted the brake disc.
Chassis consists of two guided skiing with amortization leaf springs and two screw drum tracks with their pendants. The drums are riveted, not hermetically, with claws on the stainless steel, the number of taps of winding — 4. Step hooks 1100 with the corner on the drum of 40°. Propulsion rear suspension, which allows them to have better traction to overcome the irregularities of the path.
Steering snegohod — with the usual steering wheel and the rack and pinion type; connection with the swing arm wad — rods.
Should focus on the developed in the Gorky Polytechnic Institute named after A. A. Zhdanov machines special purpose. In 1968 went to trial special all-terrain vehicles on screw propellers of the type GPN-63 and GPI-72, created under the leadership of Professor A. F. Nikolaev (see: “M-K”, 1972, No. 4). These machines, having a high installed power, equipped with hermetic screw drums of large diameter, which provide the possibility of free movement not only on snow or snow covered ice at a speed of 20 km/h, but even water and impassable swamps. They are mounted ice-milling for pokalyvanie ice around the overwintering of vessels in the Northern ports to protect from destruction by ice of hydraulic structures. When the ice thickness is 1.5 m, the speed of this milling drilling reaches 560 km/h.
Of great interest and the car of GPI-92, specially designed for mechanization of handling jobrani precipitation at the sites of treatment plants of large cities. Such ponds have an area of several hundred hectares and in need of modern treatment facilities to absorb in large cities to 16000 m3 jobrani precipitation per day. Being dehydrated, these masses can be used in industry and agriculture. But experience has shown that the cycle of dehydration is delayed by a few years, mainly due to eutrophication of surface weeds, which prevent intensive evaporation of moisture.
Machine GPK-82 showed good patency of eponym the settling tanks at any humidity, and the rotary-screw propulsion besides destroying and intensely immersed in their vegetation without the use of any additional attachments. They mix the top layer to a depth of 500-600 mm, which contributes to a more intensive evaporation.
With the engine power of 115 HP and diameter sealed rotary screw reels 800 mm machine provides speeds of 5 to 20 km/h, depending on the degree of humidity of the sludge.
Powerful machine for screw propellers and the bulls created at the Moscow Likhachev automobile plant. Snegohod SN-I is equipped with the engine in 180 HP and sealed rotary screw reels with Ø 800 mm, working hook trapezoid shape with a height of 120 mm and a tilt angle of 17°. To increase the hardness on the inner surface of the drums sprayed a layer of polyurethane. The machine is designed for driving in deep snow, swamps.
The unusual design of the screw swamp machine created in the Moscow Institute of national economy named after M. N. Gubkin. Its two screws revolving in opposite directions, allow you to move forward and backward; when they move in the same direction, the machine can move sideways, and even on the pavement. The marsh buggy is designed to transport drilling equipment for difficult soils, for example, a cargo platform on an air cushion.
From foreign cars of particular interest is the Japanese model of snegohod “Dorothy”. She has not two, but four of the screw, are successively placed two on each side. And any screw can rotate in both directions. Thanks to this, the machine offers exceptional manoeuvrability.
Not paid attention to the rotary-screw propulsion and enthusiasts of technical creativity. In 1965, engineer P. Gavrilov from Temirtau proposed to convert the standard car “Victory” with the two screws and front control ski. Augers mounted on special brackets with no elements of depreciation and was put into rotation of the propeller shaft coming from the engine attached to the gearbox with angle gear.
The same author a ski-winding machine in which a screw drums had a hydro-pneumatic shock absorbers, which improved the traction of the propeller with the ground ka track irregularities.
In 1973, the engineer P. V. Oleynikov from the village of Zarechensk, Murmansk region built seconardy CRAB-1. We must pay tribute to the persistence of Amateur technical creativity: it took three years to make the machine not only efficient, but also reliable: it is operated during the winter period without a break.
A structural diagram of a snowmobile, GPI-05.
Screw propeller design P. Gavrilov and his snegohod on the basis of the car “Victory” M20:
1 — driven ski, 2 — reducer, 3 — engine, 4 — radiator and cooling fan, 5 — driveshaft, 6 — screw propeller, 7 — thrust bearing.
Scheme nekonet P. V. Oleinikova:
1 — driven ski, a 2 — thrust bearing steering column, 3 — body, 4 — steering column 5 — the wheel 6 — seat driver and passenger, 7 — gas tank; 8 — engine, 9 — reducer, 10 — clutch connection between the engine and gearbox, 11 — circuit of the auger drive, 12 — bearing 13 — sprocket driven, 14 — axis screw, 15 — screw, 16 screw hooks, 17 — front bearing, 18 — rotary axis frame screw, 19 — shock absorber, 20 — resistant rubber pad, 21 — spring; α — angle of deflection of the frame of the screw relative to the housing.
Seconardy CRAB-1 is composed of a ski-hull, single screw, motor installation, and one controllable front ski, which is when traffic compacts the snow in front of the screw. The housing has a U-shape: one side, provided with undercuts, sliding on the snow, and the cutout is placed auger. Undercuts neutralize the lateral forces that arise on the working of the screw, providing a stable linear movement of the machine. And the plane of the ski to limit the space in which works the screw, which greatly increases its efficiency. Mover attached to the frame that the front part pivotally krupitsa to the power nodes of the U-shaped cutout. Her rear is not connected with the body-ski and beyond its rear edge. It using a special bracket mounted engine of IZH-56 with forced air cooling and the gear (reverse). The latest from/Ogulin from the rear axle, the wheelchair sidecar. From the gearbox to the auger drive Assembly is chain transmission.
This scheme when driving the screw, the frame together with the engine to move in a vertical plane, providing improved adhesion of the mover with the road on rough. This also contributes to optimal load auger, bearing the weight of the engine and the gearbox.
Mover, as in all such machines, is a cylindrical drum Ø 320 mm and a length of 1500 mm with three helixes of hooks that are shifted relative to each other by 120°. Step hooks 450 mm — this means that for one revolution of the screw moves forward at 0.45 m. – Start spiral increases the grip on the snow, as at a distance of 1.5 m in Length screw in the gearing involved . at the same time 9 ribs. For the manufacture of hooks, the designer used the worn-down discs from the clutch of the tractor.
Steerable ski is equipped with a soft suspension from leaf springs, two shock absorbers from a moped “Riga” and limiters: rubber cushions that prevent hard impacts and protect the spring from damage.
Even such a brief overview snegohodnyh machines shows that the development of this particular kind of transport equipment continues, as the search for new design solutions.
I. NIKOLAEV, engineer
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Every year more and more intensive is the development of remote areas of the country that holds in its bosom untold wealth, so necessary to the national economy. Finding these hiding places of nature, there are numerous exploration party. They travel hundreds and thousands of miles of impassable tundra, cross bogs and swamps not freezing in the harsh winters of the river, deep snow.