Remembering the history of the creation of a homemade snowmobile, I realized how long ago my passion for designing equipment began. Even in my youth (and now I am already a pensioner) I received the specialty of a locksmith and mastered welding and other specialties of metalworkers on my own. But to tell the truth, he could not “boast” with his knowledge of design, and there was nowhere to learn. On a whim, he built all sorts of “dryndhods” on wheels and caterpillars: he rode them both off-road and in the snow, but there was neither reliability nor beauty in them.
But at the beginning of 1988, “Modeler-Constructor” was published, in which there was an article about the snowmobile “The caterpillar around the ski”. This is where it started!
Our places are such that the snow cover lies for six months or even more! Local roads are usually cleaned at the wrong time, and even then in such a way that only an all-terrain truck can pass. Well, there is nothing to say about country roads. In addition, I had hobbies: hunting and fishing. That's all this and spurred to make a solid passable snowmobile.
I built it for myself, helped friends, relatives, gained experience. He constantly improved the design “according to the laws of evolution”: he replaced the heavy one with a light one, the unreliable one with a strong one, introduced suspensions: spring, spring, shock absorber. In total, he built more than a dozen snowmobiles: on caterpillars with wooden and polyethylene tracks around a ski-skiz; rubber with a block of rollers; and with one control ski, and with two.
I'll tell you a story about my last snowmobile. I can’t say that it has no flaws, but I put all the accumulated experience into its design and the car turned out to be successful, although without frills (or, as they say now, utilitarian), but it looks good, and reliability is on height.
The layout of the snowmobile was chosen as the most common, both on similar domestic vehicles and on foreign ones: two front steerable skis; power unit located in front under the hood; further - the caterpillar block, and above it is the seat and behind it is the trunk. The total length of the snowmobile is 2300 mm, the width along the outer edges of the skis is 900 mm, the height to the steering wheel is 1000 mm, to the seat is 700 mm.
1 - controlled ski (2 pcs.); 2 - controlled ski suspension (2 pcs.); 3 - arc (pipe Ø32); 4 - hood (from the side trailer of the motorcycle "Java"); 5 - windshield; 6 - steering wheel; 7 - fuel tank (welded from two moped); 8 - seat; 9 - tool box; 10 – trunk guard (pipe Ø16); 11 - mudguard (steel sheet s0.5); 12 – spring shock absorber for the suspension of the tension pendulum levers of the caterpillar block (2 pcs.); 13 - headlight; 14 - caterpillar block
1 – lower spar (pipe 28×25, 2 pcs.); 2 - upper spar (pipe 20 × 20, 2 pcs.); 3 - L-shaped bracket for fastening the support bearing housing of the power unit output shaft extension (pipe 28 × 25); 4 - pod-kosnaya interspar rack (pipe 20 × 20); 5 - removal (pipe 28 × 25.2 pieces); 6 - support plate of the steering shaft cup (steel sheet s3); 7 - a glass of the steering shaft (pipe Ø32); 8 – steering column (pipe Ø32); 9 - stand-arc, 2 pcs.); 10 – seat frame (pipe Ø20); 11 – seatpost (pipe Ø20); 12 - strapping of the tool box (steel corner 20 × 15); 13 - welded bracket for fastening the caterpillar block and the tension of the caterpillar (2 pcs.); 14 - bracket brace (pipe 20 × 20, 2 pcs.); 15 – semi-frame of the luggage area (pipe 20×20); 16 - rear shock absorber mounting lug (steel s4.2 pcs.); 17 - strut of the semi-frame of the trunk (pipe 15x 15.2 pcs.); 18 - brace of the lower spar (pipe 28 × 25.2 pcs.); 19 – traverse (pipe 28×25); 20 – cross member of extensions (pipe 28×25); 21 – steering column suspension cross members (pipe Ø16); 22 – motor subframe (pipe 28×25); 23 - coupler-support (steel plate); 24 – cross member of the lower spars (pipe 28×25); 25 - tie-lock of the fuel tank; 26 - a longitudinal element of the seat niche (pipe 20 × 20.2 pieces); 27 - kingpin bushing (bicycle, reinforced, 2 pcs.); 28 - strut of the kingpin bushing (pipe 20 × 20, 2 pcs.)
Under the hood:
a – right side view; b – left side view
The power unit (engine, clutch and gearbox in one unit) is Tula-200m manufactured by TMZ (Tula Machine-Building Plant). It was put on any motorized equipment manufactured in Tula: scooters (including the cargo Ant), motorcycles, etc. The unit is quite reliable, although heavy.
The power of the new motor was 11 hp. with speed up to 3600 per minute. But he is no longer a decade old. However, eight or nine forces, according to my feelings, are still preserved in it. The engine has a working volume of 196 cm3, two-stroke and runs on a mixture of low-octane gasoline with engine oil (Avtol type) in a ratio of 10:1.
The cylinder is equipped with regular forced air cooling.
The gearbox has a gear ratio of 2.353.
To transfer rotation from the secondary (output) shaft to the drive shaft sprocket, it was necessary to make a welded extension from a pipe with slotted tips. At one end, internal splines are cut directly into the pipe (for fitting the extension onto the shaft). On the other - external slots for the adapter, a seat for the bearing and a M20x1.5 thread for mounting on the sprocket extension, made on a welded tip.
Looking ahead, I note that exactly the same tip is welded to the drive shaft of the caterpillar, which is made from the tension rear axle of the caterpillar from the Buran snowmobile.
The snowmobile frame is spatial, welded from steel pipes of rectangular, square and round sections.
The basis of the frame is two paired tubular spars - upper and lower. The upper spar of each pair is made of a pipe with a section of 20×20 mm. From the same pipe and most of the auxiliary elements: intermediate crossbars, struts and even the rear frame of the luggage area. The lower spars - from a pipe with a section of 28 × 25 mm - this is the thickest pipe in the frame structure. From the same pipe, the front traverse, front cross members and consoles, sub-engine ridge.
I must say that the frame pipes are small and not even thick-walled sections. And therefore, in places where I drilled holes, I inserted bushings into them and welded them in a circle.
The superstructure of the frame (racks, arcs) is made of a round pipe with a diameter of 20 mm - from old chairs, thin-walled, but strong enough. But it was difficult to weld them, but if this is done using a semi-automatic device, the process is greatly facilitated. The frame of the trunk under the seat, as well as the frame of the middle part of the platform, is made of an equal-shelf 15-mm corner. Between these frames, I put long items, such as skis. The steering shaft column - made of a 32 mm diameter tube - is integrated into the front of the superstructure. Pivot bushings are cut from bicycle frames and welded to the ends of the crosshead. The brackets of the caterpillar tension units are also integrated into the frame (welded to the rear ends of the lower spars). The same brackets also serve as attachment points to the frame of the caterpillar balancer shaft bearing housings. In addition, numerous ears, eyelets for installing the power unit, fuel tank, seat, shock absorbers, etc. are welded to the frame elements.
1 - extension; 2 – a tip for a nozzle on a shaft; 3 - tip for the drive gear
1 - caterpillar; 2 - caterpillar drive gear (2 pcs.); 3 - caterpillar drive shaft assembly; 4 - spring (2 pcs.); 5 - bracket of the balancing block (2 pcs.); 6 - pendulum lever of the tension axle (2 pcs.); 7 - tension gear of the caterpillar (2 pcs.); 8 - track roller (10 pcs.); 9 - extreme trolley (2 pcs.); 10 - medium cart; 11 - axis of the balancing block; 12 - supporting roller (2 pcs.); 13 - housing with a bearing of the axis of the balancing block (2 pcs.); 14 - bracket for fastening the spring to the axis of the balancing block (2 pcs.)
The caterpillar block (more precisely, its longitudinal half) was borrowed from the old Buran industrial snowmobile. Why half? Yes, because, firstly, it is easier. Secondly, there are less costs and a simpler design. Well, and thirdly, I intended to ride not on the virgin snow, but in the footsteps of the "pioneers".
However, in combination with a pair of rather wide skis, the snowmobile confidently overcomes both deep snowdrifts and freshly fallen “powders”.
The outer bogies have been redone - the springs have been removed, and the bushings are welded together, as the bogies balance on their own, sitting on their axis at the ends of the springs.
The track tensioner has also been redesigned. The front ends of its pendulum arms sit on a common axle with a spring balancing unit, and the rear ends are suspended on self-made spring shock absorbers to the frame.
The propulsion of the snowmobile is a rubber caterpillar 380 mm wide (there are two of these on the Buran). The caterpillar drive is carried out from the drive shaft through a pair of 9-tooth "Buranovsky" kapron wheels. The drive shaft is tubular. As noted earlier, it is made from the rear tracked "Buran" axle, mounted in 80205 bearings, the housings of which are attached directly to the upper frame spars. The tension of the caterpillar is carried out by a tension axle with gear wheels (the same as drive wheels) through a pair of pendulum levers mounted on the axle of the balancing bogie (by moving its bearings along the frame spars). The tension shaft of the caterpillar (or rather, the axle, since this part does not transmit torque) with gear wheels is also “Buranovsky”. The contact of the caterpillar with the road along the length is a little more than a meter.
Previously, he built propellers with a support ski-ski. They are good on "puffy" snow and snowdrifts, but are very sensitive to hard bumps in the road. From them - not only discomfort is transmitted to the driver, but breakdowns of the tracks and even the slide itself occur. Therefore, this time I decided to make a mover with a rubber caterpillar and track rollers, as I intended to drive on rolled snow and even ice.
The transmission of a snowmobile, as they say, could not be simpler, although not without zest. It consists of a single-stage chain drive from the IZH motorcycle with a pitch of 15.875 mm with a pair of sprockets: the drive has 15 teeth, the driven has 21, that is, the gear ratio is 1.6. The secondary (output) shaft of the power unit is extended by a pipe with internal splines on the end mounted on the shaft and a splined tip on the other. The free end of the extension is mounted in bearing 80205, the body of which is fixed on an L-shaped bracket welded to the frame. A chain drive sprocket is mounted on this tip through an adapter with internal and external splines. The driven sprocket is planted (also through a splined adapter) on the splined tip of the caterpillar drive shaft. I made adapters from gears: annealed, machined, milled. Thanks to splined adapters, the sprockets (and, consequently, the gear ratio) are easy to change even in field conditions under road conditions (more precisely, under the density and depth of snow cover).
Guided snowmobile skis are homemade, 900 mm long (blank - 1000 mm) and 200 mm wide. Made from 2mm thick steel sheet. The runners are stamped: in the middle there is a triangular groove, and along the edges there are flanging-undercuts, bent up in front (contact surface with snow - 800 mm). From above, longitudinal stiffening ribs of a U-shaped section, curved from the same steel sheet, are welded to the skids, and ears and eyes for attaching suspension units are welded to them, and in front are shackles made of a 10-mm steel bar.
Each ski has a suspension consisting of a shock absorber (from the Tula scooter) and a homemade lever made of a 20 × 20 mm square tube.
Steering - mixed type. The steering wheel itself is a motorcycle lever, and the rest is like a car. The steering shaft is a “breaking point” with a cardan joint and even a kind of steering mechanism. He made it a “turning point” because he did not enter into a “parallel” with pivot bushings in any way (but, in fact, a straight shaft is better). It should be noted that the lower end of the shaft was structurally ahead of the swing arms and rods, and the bipod was directed backwards. In this position, when turning to the right, the steering wheel had to be turned to the left, and vice versa, which was contrary to common sense. Therefore, it was necessary to introduce a steering mechanism that serves to coordinate the turn of the steering wheel and the direction of the skis. The mechanism is a pair of identical gears in a housing. The drive gear is splined onto the end of the steering shaft, and the driven gear shaft is connected (welded, although this assembly is expedient and easy to make also collapsible) with a T-shaped bipod. From the bipod through the steering rods and steering knuckles, the skis are now simultaneously rotated in the same direction as the steering wheel is turned.
Equipment. The fuel tank is welded from two tanks from the Riga moped.
The seat - from the motorcycle "Minsk" is mounted on racks with sheathing made of duralumin sheet. Under the seat there is a tool box, and between the box and the floor there is a free niche with an opening at the back. If necessary, I put skis, a shovel and other long items in it. The hood is a redesigned front part of the stroller (side trailer) of the Java-350 motorcycle. Electrical equipment is standard. Headlight - from the motorcycle "Minsk".
1 - snake; 2 - amplifier; 3 - bow; 4 - shock absorber attachment eye; 5 - lever mounting eye
1 - steering wheel (bicycle); 2 – the top knee of a steering shaft; 3 - bracket for supporting the upper knee of the steering shaft (furnishings); 4 - universal joint; 5 - steering column; 6 - the lower knee of the steering shaft; 7 - clamp spline connection of the lower knee and the pinion shaft; 8 - drive shaft-gear; 9 - driven shaft-gear; 10 - bipod; 11 - the axis of the bipod and steering rods; 12 - steering rod (2 pcs.); 13 - tip for adjusting the length of the steering rod (2 pcs.); 14 - locknut 15 - steering lever (2 pcs.); 16 - axis of thrust and lever (2 pcs.); 17 - steering knuckle (2 pcs.)
1 - receiving branch pipe; 2 - body; 3 - silencer; 4 - outlet pipe
1 - drawbar; 2 - cross member; 3 - bracket-eye (2 pcs.); 4 - thrust (2 pcs.); 5 - ski (2 pcs.); 6 - body; 7 - rack (10 pcs.)
Sledge trailer - homemade. I think it's better to have a small sled than a big trunk on a snowmobile: if you get stuck somewhere, you can unhook the sled, tread the path and hitch it again. The body was once the body of the side trailer of the Java-350 motorcycle, or rather what was left of it after the manufacture of the hood for the snowmobile itself. It was shortened by cutting out about 200 mm in the middle. Then I riveted the front and back parts with pop rivets. Under the body, I placed several crossbars from a rectangular pipe 40 × 20 mm, one of the wide walls of which was left as ears at both ends. The ears were attached to the sidewalls of the body with rivets.
The body is mounted on skis from aluminum panels of the electric busbar by means of tubular racks of square section 20 × 20 mm. Racks at the top are welded to the crossbars with ears and at the bottom - to the "heels" - steel square plates 2 mm thick. I riveted the “heels” to the ski runners with the same rivets.
I want to note that the drawings of the nodes are not working, but introductory: some do not have all the dimensions (for example, frames), somewhere something may not match, since the drawings were made according to an already finished design.
But in general, I believe that the manufacture of a structure according to drawings is already production, and not creativity.
V. SMIRNOV, Syava village, Nizhny Novgorod region
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