SKIS AND CATERPILLAR

The prototype design was quite successful and was repeated with slight variations dozens, maybe even hundreds of instances across the country. However, I learned recently, thanks to the Internet. Still alive handmade from the 1990s and there are new versions with imported power motoagricola.

Amazing and nice thing is that now when snowmobiles industrial production, both domestic and imported, in abundance, are enthusiasts and craftsmen create in their garages “thoughts” drawings of the journal “modelist-Konstruktor”. On the Internet on websites homebrew snowmobile praised for its simplicity, manufacturability and repair in terms of the garage workshop and even fuel efficiency.

 

 

 

 

 

 

 

The present article is a description of the design of the latest snowmobile is called “Chuk-125” made in 1995, when I was still working on Zavodoukovskaya station of young technicians. Its construction took into account the shortcomings revealed in previous designs, and also applied some new solutions So it would be a shame if they are not learned readers.

 

Design description

 

“Chuk-125” — a single truck mount snowmobile with a crawler gear and asymmetrically (right side) are located under the engine of the motorcycle M-103, which provides the car an acceptable dynamic Two swivel skiing, short base and low center of gravity give this a fairly compact “snegohodi” enviable maneuverability (while ensuring sustainability), and a fairly wide caterpillar tracks-“negotatiate” from wooden bruskov section 45×25 mm ensures good permeability in the virgin snow.

 

The location of the engine right of the seat, it is advisable constructively, in this case, you can dispense with the intermediate shaft, which greatly simplifies the drivetrain and improves the reliability of equipment. The difference from the previous snowmobiles that drive chain from the sprocket of the output shaft of the power unit to the driven sprockets of the drive shaft of the caterpillar now is between the frame spar and the caterpillar, that is, the right end of the drive shaft caterpillars are now not performing as before, the dimensions of the console of the snowmobile, which significantly unloaded the nearest bearing. Right side member thus serves as a fence of the chain.

Under your right foot — long shift lever, and floor-level platform — kick-starter, but now it’s not the foot lever, and crank. Here I’ll note that it is possible to start the engine and “pusher” by the wayside, and in extreme cases, subject to precautions, by pulling caterpillar hands from the trunk.

 

The frame is welded. It is collected from the corners of 45×45 mm (spars) and round tubes of different diameters (cross member, struts, crossmember) with a home welding unit ADZ-1 and electrodes SSSI. Pipe bending is done by hand, the simplest Bush bending with a long handle. Bushing steering knuckle, brackets, eyelet cradle support ski supporting the ski and other accessories welded in place during Assembly on the stocks so the exact location (reference dimensions) in the drawing frame is not specified.

 

 

The drive unit of the caterpillar:

 

1 – driving gear tracks (rubber, sheet s25, 2 PCs); 2 – drive shaft (tube Ø42×5); 3 – clamping the drive gear wheel (become, the sheet s5, 2pcs); 4 — cheek gears (steel, sheet s5. 2); 5 -solitaire (steel, sheet s5, 8); 6 — shaft tip (steel, circle Ø42, 2); 7—hub drive sprocket (steel, round Ø60); 8— drive sprocket (z = 13, t = 12,7); 9 — pin (Ø8×60); 10 — connecting the toothed wheel with a cheek and disc (М8х46 bolt with washer, 8 — sets); 11 — bearing housing (steel, circle Ø48, 2 pieces); 12 – base of the bearing housing (steel, sheet s5); 13 – bearing 80203, 2 PCs.)

 

 

 

Caterpillar is a defining node of the snowmobile. It is completely homemade. Slide the supporting skis on permanently covered with snow or icy tracks is almost not hindered, and sufficient torque is provided even small motors. Looking ahead, I note that had experience of similar equipment of a snowmobile, even a 50-CC engine. And with him, the snowmobile slowly moving from “training” rate. With this engine, the snowmobile is classified as “disenfranchised” — it is teenagers from 14 pet without a license and car registration in the bodies of technical supervision. The caterpillar is made of two identical parallel strips of the conveyor belt, interconnected evenly spaced across the tracks from birch planks.

 

The tension of the tracks is produced by moving the driven shaft threaded tensioners. It should be noted that in this construction the tension of the toothed wheels were replaced with rollers, which not only simplified the design of the propeller, but ruled out such an unpleasant phenomenon as nasoceana tooth idler on the truck when there is insufficient tension in the tracks or getting between them chunks of ice.

 

Reference ski. It performs several functions: it provides load distribution on the entire area of contact with the snow, serves to guide the track and the sliding surface for trucks. Ski base is made of birch plywood 10 mm thickness. The front and rear ends of the skis are bent. Below, it is lined with sheet polyethylene, 5 mm thick

 

Excellent for padding of the sole (bottom surface) reference ski is sheet nylon, but at the time this material was very scarce. You can sheathe and a separate longitudinal strips.

 

Ski support Assembly is attached to the frame on axes through the brackets with rubber bushings, which gives her the ability to balance and to dampen the vibration while sliding in the tracks and softens the blows from the ice, rescuing the wooden trucks from damage.

 

Support ski — snowmobile track — new. It provides a smooth entry of caterpillar to the driven gears star in “ragged” driving (with alternating acceleration). Ski support made of dural sheet and mounted on milongero the crossmember.

 

The front skis of different width. Right (in the direction) is 20 mm wider than the left to compensate for the unbalanced weight distribution — the lateral location of the power unit. The toe of the ski reinforced tubular brace, to which clings the control return spring

 

The inclined location of the steering knuckle and guide the undercuts of the area make it easy to maneuver on the snow and rolled on the road. For depreciation of the ski and protect the frame from impacts on the strut steering knuckle worn damper springs.

 

Parallel ski control is a prerequisite of ease of control. This adjustment of their mutual position is performed by a threaded coupling on the steering rods. The skis do not create unnecessary resistance and save fuel.

 

To improve the traction characteristics of the engine reduced combustion chamber, and the mechanical ignition changed to electronic.

 

Cylinder engine has a homemade air cooling system. Two-bladed radial impeller is mounted directly on the elongated bolt rotor ignition that is very simple and reliable! The heated air from the cylinder of the engine fan cowl is directed into the legs of the driver.

 

The windscreen is not (although nothing prevents to install it), but due to the selected angle of the fairing counter air goes up and almost don’t care.

 

“Chuk-125” equipped with one directional light, mounted in a plywood fairing.

 

Runners of governors of the ski is made from ordinary 10-mm plywood. Bending the bow is achieved through a dynamic warm-up of the workpiece with a blowtorch, abundant irrigation water and smooth bending in the fixture. After cooling skids of plywood soaked in linseed oil, painted and lined with polyethylene sheet. Base plate, angles, lugs fastening the skis to the steering knuckle is made at the same time. Bent front skid socks reinforced tubular lugs that will not only protect them from breakage, but also serve as convenient handles for pulling out a stuck snowmobile and the seat attachment the stretching of the springs. The stretching of the spring to save the ski from pecks and cuts in the snow when moving through the snowdrifts and other obstacles.

Reference ski is made in a similar way. In comparison with the great snowmobile “Idea-2” the design of it is simplified: no copper wear plates and cut under tooth-gear drive wheels. Simplification did not affect the performance and knot strength of the structure.

 

Track mover consists of front drive shaft with rubber gears, rear output shaft with rubber rollers, supporting skis, two supporting skis and the track.

 

Caterpillar Assembly consists of two strips of rubber conveyor belt cross-section mm 40×10, to which increments of 90 mm bolted cross birch Truckee. The fastener consists of М8х60 bolts, M8 nuts, guiding-clamping bonok widened and thick-walled duralumin washers. The connection of the ends of the tracks — back to back with the lining from the same conveyor belt and draw bolts through washers.

 

 

 

 

 

 

 

 

 

 

 

Manufacturer bonok may chill the casting in the form of aluminum debris. Drilling holes in the bands and tracks were produced on templates.

 

Driving and driven shafts are welded with a preliminary check for a heartbeat and curvature. For normal operation, a special accuracy is not required. The curvature of the lugs of the shaft and the axis kompensiruet use self-aligning bearings.

 

Leading gears are cut with a sharp knife from a sheet of rubber (from the sidewall of the tire from the tractor K700 with water as lubricant). Accurate method of cutting is that first made a template of the star with holes for mounting. Then the shaft is slipped a rubber blank with a template, is attracted by regular bolts and cut.

 

On the frame, the spars in the first place, marked and drilled holes for mounting the bearing housing with the drive shaft. Then on the actual size of the track is determined by the place of attachment of the driven (idler) shaft and propisyvayutsya grooves to allow movement of the bearing bodies with the aim of track tension.

 

The lugs of the mounts of the supporting skis should be welded after installation on the frame of the driving and driven shaft and tension track: put flatter relative to the frame, and the guide bosses and weld.

 

Fixing the retaining lugs ski also welded in place with a slight decrease from the line of the upper branch of the caterpillar, to the floor of the caterpillar, it is desirable to attach two wooden longitudinal slats, which will protect the plywood from eating away the threaded part of bolts.

 

One of the important conditions of the build — parallelism of the supporting skis of the longitudinal corners of the frame spars and the required location of her sole below the outer diameter of the rollers of the driven shaft 15 — 20 mm.

 

The engine Assembly from the mounting face, the mounting brackets are exactly exhibited at the driven sprocket to the drive shaft of caterpillar tracks and cheeks prihvatyvayut welding. The final fusion of the cheeks is done already when removing the engine, the chain Tensioning is performed the tensioning roller.

 

Veneer consists of front fender-fairing, floor, and tool kit under the seat. Fairing and floor are made of birch plywood, and the box — sheet duralumin Mounting tabs are welded in place.

 

The seat is made on the basis of sheet steel glued to his pillow of foam covered with a durable waterproof leather. The seat to the frame tool box, mounted here by means of a hook and is fixed (locked) onto the fork with a bolt and wing nut.

 

A few recommendations to those who decide to build a snowmobile:

 

— well served and pine Truckee (failed tracks of nylon pipe);

 

— proportional increase of all sizes can build a snowmobile under a more powerful engine (from “IZH-the planet Jupiter”);

 

— for all skis, you can apply a 6-mm plywood in two layers;

 

— under the new laws of 1996 homemade equipment with an engine capacity over 50 CC must carry on the examination and to put on record in supervision;

 

— two people of average build “PAAs-125” still lucky(!);

 

— handy drag hook to the sled or sleds:

 

— removing steering skis may be carried in the “UAZ” and “Niva”;

 

— mechanics for beginners is better to install the imported engine of comparable power — this will be less of a hassle.

 

A. MATVEICHUK, Zavodoukovsk, Tyumen region.