SNOWMOBILE Recalling the history of the snowmobile, realized how long ago began my fascination with construction equipment. Even in his youth (and now I’m already retired) received the specialty of a locksmith and mastered on his own welding business, other specialty Metalworkers. But knowledge of design, to tell the truth, “boast” could not, and to learn there was no place. Built on a whim any “grindaholik” on wheels and tracks went on them and on the road and in the snow, but neither the reliability nor beauty.

But in early 1988 came “modelist-Konstruktor”, which had an article about the snowmobile “Caterpillar around ski”. Here and started!
We have a place such that snow lies for six months or even more! Local roads are clean, usually not on time, and so that only all-terrain truck could pass. Well, on the country roads nothing to say. Besides, I had Hobbies: hunting and fishing. That’s all it convinced to make a traversable snowmobile.
Built for myself, helped friends, family, gaining experience. Constantly improved the design of the “laws of evolution”: replaced the heavy – light, weak – to strong, implemented suspension: spring, spring-loaded, shock-absorbing. Total built more than a dozen snowmobiles: on tracks with wooden and plastic tracks around the ski-skiza; rubber block rollers; and administering one ski and two.
the story will lead on his last snowmobile. Can’t say he has no flaws, but in its construction I have put all the experience and the machine was, like, a good, albeit no-frills (or, as they say, utilitarian), but it looks good, and reliability at altitude.
Layout scheme of a snowmobile are the most common, how such domestic machines and foreign: two front steer skis; the power unit, located in front under the hood; hereinafter, the crawler block, and above him the seat and behind the trunk. The total length of snowmobile – 2300 mm, width at the outer edges of the ski 900 mm, height of wheel – 1000 mm, to seat 700 mm.
Snowmobile “Snowbird”:
1 – managed ski area (2); 2 – controlled suspension skis (2); 3 – arc (pipe Ø32); 4 – hood (from the side of the trailer a motorcycle “Java”); 5 – windscreen; 6 – wheel; 7 – fuel tank (welded of two moped); 8 – seat 9 – tool kit; 10 – the plug of the trunk (tube Ø16); 11 – the splash guard (sheet s0,5); 12 – spring absorber suspension suspended pendulum levers crawler unit (2); 13 – beam; 14 – track unit

Snowmobile frame
The frame of the snowmobile:
1 , the lower spar (tube 28×25, 2); 2 – top side rail (pipe 20×20, 2); 3 – l-shaped bracket housing bearing-extension of the output shaft of the engine (pipe 28×25); 4 under inert melongena strut (tube 20×20); 5 – stem (pipe 28×25,2); 6 – glass support bar of the steering shaft (sheet s3); 7 – Cup steering shaft (pipe Ø32); 8 – steering column (tube Ø32); 9 – front-arc, 2); 10 – seat frame (tube Ø20); 11 – front seat (tube Ø20); 12 – rail tool box (steel area 20×15); 13 – welded mounting bracket track unit and tension of tracks (2); 14 – brace bracket (pipe 20×20, 2); 15 – polurama platform boot (tube 20×20); 16 – eyelet rear shock (steel s4,2); 17 – brace panoramki trunk (pipe 15x 15,2 PCs); 18 – brace the bottom of the spar (tube 28×25,2); 19 – cross member (tube 28×25); 20 – cross of stems (pipe 28×25); 21 – roll bars front and rear steering column (tube Ø16); 22 – engine subframe (pipe 28×25); 23 – a rod-bearing (steel plate); 24 – crossbar bottom of the spar (tube 28×25); 25 – screed-fuel tank lock; 26 is a longitudinal element of the seat niche (pipe 20×20,2); 27 – Bush king pin (Bicycle, reinforced, 2 PCs.); 28 – brace bushings king pin (pipe 20×20, 2 PCs.)

Under the hood: a - right; b - left-side view Under the hood: a - right; b - left-side view
Under the hood:
a – right; b – left side view
The power unit (engine, clutch and gear shift in one unit) – “Tula-200m” produced by TMZ (Tula machine-building plant). He was placed on all made in the Tula motorcycles: scooters (including in cargo “the Ant”), motorcycles etc. the Unit is fairly reliable, although heavy.
The power of the new motor was 11 HP with a speed of 3600 per minute. But he has more than a dozen years. However, the strength of eight or nine, my feeling is that it still has. Engine working volume of 196 cm3, two-stroke and runs on a mixture of low-octane gasoline with engine oil (type “Avtol”) in a ratio of 10:1.
The cylinder is supplied with standard forced air cooling.
The gearbox has the gear ratio is 2,353.
To transmit rotation from the secondary (output) shaft to the sprocket drive shaft had to make a welded extension pipe with slotted tips. At one end of the internal splines cut directly into the pipe (for mounting the extender to the shaft). On the other – the outer slots for the adapter that seats in the bearing and thread M20x1,5 for mounting on extension sprocket, made to weld the tip.
Looking ahead, I note that exactly the same tip is welded to the drive shaft of the caterpillar, which is made of stretch rear axle of the track of a snowmobile “Buran”.
The frame of the snowmobile – dimensional, welded from steel pipes of rectangular, square and circular cross-sections.
The base of the frame two pair of tubular side member – upper and lower. The top side member of each pair is made of a tube section 20×20 mm. Of the same pipe and most of the auxiliary components such as intermediate cross-members, struts, and even the rear frame of the Luggage area. The lower side members – of the tube section 28×25 mm is the thickest tube in the frame construction. From the same pipe and the front cross member, front crossmember, and console sub range.
I must say that the tube frame – cross section small and even not thick. But because in places where drilled holes in them inserted into the sleeve and welded in a circle.
The superstructure of the frame (pillars, arc) made of round pipe with a diameter of 20 mm, from old chairs, thin-walled, but strong enough. That’s just welding them was quite difficult, but if it is done by the apparatus-semi-automatic process much easier. The frame of the trunk under the seat, like the frame of the middle part of the site, from angle 15-mm area. Between these frames I put long stuff like skis. Column steering shaft – diameter tubing 32 mm – integrated in the front part of the superstructure. Sleeve swivel pins cut from Bicycle frames and welded to the ends of the beam. The frame is also integrated (welded to the rear ends of the lower spars) brackets nodes of track tension. These brackets and serve as attachment sites to the frame bearing balance shaft belt. In addition to the elements of the frame is welded of numerous lugs, lugs for mounting the power unit, fuel tank, seats, shock absorbers etc.
The extension of the secondary (output) shaft of the engine (weldment)
The extension cable is the secondary (output) shaft of the engine (weldment):
1 – extension; 2 – tip for attachment to the shaft; 3 – a tip for drive gear

Fig. 4. Crawler unit
Fig. 4. Crawler unit
Fig. 4. Crawler unit:
1 caterpillar; 2 – drive gear caterpillar (2); 3 – node of the drive shaft of the caterpillar; 4 – spring (2 PCs); 5 – bracket, balancer unit (2); 6 – pendulum tension axis (2); 7 – a tension gear wheel caterpillar (2); 8 – support roller (10 PCs); 9 – extreme truck (2 PCs); 10 – medium truck; 11 – axis balance unit; 12 – support the ice rink (2); 13 – housing with the bearing axis balance unit (2); 14 – the bracket springs to the axle beam block (2 PCs.)

The balance wheel of the crawler unit
The balance wheel of the crawler block
Crawler unit (more precisely its longitudinal half) is borrowed from the old industrial snowmobile “Buran”. Why half? Yes, because, first, it is easier. The second-lower costs and simpler design. And thirdly, it was suggested not to ride on the virgin snow, and the traces of the “pioneers”.
However, in combination with a pair of fairly wide ski snowmobile confidently overcomes and deep drifts, and fresh “pulaki”.
Extreme truck redone spring removed and the sleeve are welded to each other, as the truck balance themselves, sitting on its axis at the ends of the springs.
Redone and a host of track tension. The front ends of its pendulum levers sit on a common axis with a spring balancer node, and the rear is suspended on a homemade spring-loaded shock absorbers to the frame.
Propulsion of the snowmobile rubber tracks with a width of 380 mm (in the “Buran” these are two). The caterpillar drive is provided from the drive shaft through a pair of 9-toothed “buranovskiye” nylon wheels. Drive shaft – tubular. As noted earlier, it is made of the rear crawler “buranovskie” axis, is mounted in bearings 80205, which is attached directly to the upper frame rails. The tension of the caterpillars is the tensioning axis of the gear wheels (same as drive) through a pair of idler levers mounted on the axis of the tandem (moving the bearings along the frame rails). Tensioning shaft of the caterpillar (or rather – axis, since this item does not transfer torque) with gears – too “buranovskie”. Contact with the road tracks in length – slightly more than a meter.
Previously, the propeller was built with a support ski by means of. They are good for “chubby” snow and snowdrifts, but very sensitive to hard bumps in the road. From them – not only transmitted to the driver discomfort, but there are breakdowns of the trucks and even the by means of. So this time I decided to make a mover with rubber tracks and road wheels, since it is expected to go on the thumb snow and even ice.
Transmission of a snowmobile, that is, it can’t be easier, though not without highlights. It consists of a single-stage chain transmission from a motorcycle “IZH” with a step 15,875 mm with a pair of stars: presenter has 15 teeth, driven – 21, that is, the gear ratio is 1.6. Secondary (output) shaft of the power unit is extended by a tube with internal splines on placed on the shaft end and slotted ferrule at the other. The free end of the extension tube is mounted in the bearing 80205, the housing of which is secured to l-shaped bracket welded to the frame. On the tip through the adaptor with internal and external splines planted sprocket chain transmission. Sprocket driven planted (also via splined adapters), the splined tip of the drive shaft of the caterpillar. Adapters have been made of gears: annealed, bored through, offreserve. Thanks to the splined adapters sprocket (and hence the gear ratio) is easy to change even in the field under road conditions (more precisely, the density and depth of snow cover).
Managed the skis of the snowmobile – a self-made, length 900 mm (blank – 1000 mm) and a width of 200 mm, Made of steel sheet 2 mm thick. the Rails are forged: in the middle of the triangular groove, and the edges – flanging-undercuts, curved upwards in front (the contact surface with the snow – 800 mm). On top of the skids welded to the longitudinal ribs of U-shaped cross section, curved from the same sheet steel, and to them ears and eyes for the attachment of suspension units, and in front a bow of steel 10 mm rod.
Each ski has suspension consisting of a shock absorber (scooter “Tula”) and a makeshift arm out of square tube 20×20 mm.
Steering – mixed type. The drive – motor lever, and the rest – like a car. Steering shaft – the “tipping point” with u-joint and even a kind of steering. “The turning point” it was because he did not enter in parallel with the pivot bushings (and in fact, the straight shaft better). It is necessary to pay attention that the lower end of the shaft constructively came in ahead of the swivel levers and rods, and fry directed backwards. In this situation when turning right the wheel you have to turn left, and Vice versa, contrary to common sense. So I had to enter the steering mechanism that serves for the coordination of the steering and direction of the skis. The mechanism comprises a pair of identical gears in the housing. Pinion gear by a spline connection impaled on the end of the steering shaft, and the shaft the spur gear is connected (welded, although this node is reasonable and it is easy to do is also collapsible) with T-shaped bipod. From the Pitman arm through tie rods and knuckles is the simultaneous rotation of the skis are now in the same direction, which turn the steering wheel.
Equipment. The fuel tank is welded from two tanks on a moped “Riga”.
Seat – a motorcycle “Minsk” mounted on racks with the skin of duralumin sheet. Under the seat is a tool box, and between box and floor is a niche with a hole in the back. It is laid in need of skis, shovel and other long items. The hood – to redraw the front part of the stroller (side of trailer) of a motorcycle “Java-350”. Electrical equipment staff. Headlight – a motorcycle “Minsk”.
Controlled skiing
Guided ski:
1 – skids; 2 – amplifier; 3 – shackle; 4 – eyelet of the shock absorber; 5 – eyelet lever

Controlled skiing
Managed ski
1 – wheel (Bicycle); 2 – the upper knee of the steering shaft; 3 – bracket support upper joint of the steering shaft (furnished); 4 – universal joint; 5 – steering wheel; 6 – lower knee of the steering shaft; 7 – a collar splined joint the bottom knee and the pinion shaft; 8, the leading gear shaft; 9 – driven gear shaft; 10 – fry; 11 – axis of Pitman arm and steering rods; 12 – tie-rod (2 PCs.); 13 – the tip of the adjustable length tie rod (2); 14 – nut 15 – steering arm (2 PCs); 16 – axis thrust and the lever (2 PCs); 17 – steering knuckle (2 PCs.)

Diagram of the muffler
The schema of the muffler:
1 – suction inlet; 2 – body; 3 – damper; 4 – outlet

Sled trailer for a snowmobile
Sled trailer for a snowmobile
Sled trailer for a snowmobile:
1 – pole; 2 – tappet; 3 – bracket-lug (2 PCs); 4 – thrust (2); 5 – ski (2); 6 – body; 7 – (10 PCs)

Assembly of a snowmobile on the
The Assembly of the snowmobile on the “slipway”
Sledge-trailer – homemade. I think it’s better to have a small sled, the trunk of a snowmobile: if somewhere stuck, the sled can be released, the path to tread and re-attach. The body was once the case side of the trailer a motorcycle “Java-350”, or rather what is left of it after the hood to the snowmobile. It was shortened, cutting out about 200 mm in the middle. Then riveted the front and rear portions by means of rivets. Under body has placed some of the cross members of the rectangular tube 40×20 mm, one of the broad walls of which are left as Ushkov at both ends. Lugs attached to the side of the body by means of rivets.
The body is on the slopes of the aluminum panels electrogenerated through the tubular uprights of square section 20×20 mm. at the top of the Rack is welded to the cross members with ears and down to the “heels” – square steel plates with a thickness of 2 mm. the “Heel” riveted to the runners of the skis all the same by means of rivets.
I note that the drawings are non-working and study: some indicated not all dimensions (e.g., frames), where something may not be the same as the drawings were made on existing designs.
But in fact, I believe that the production of construction drawings – it is production, not creativity.
V. SMIRNOV, p. Syava, Nizhny Novgorod region.

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