CATERPILLAR AROUND THE SKI: THE EXPERIMENT CONTINUESWith the magazine “modelist-Konstruktor” I’ve known since high school, often picked up from the magazine interesting ideas, implemented them. Over time, accumulated their own experience, appeared and their development. One of them I want to offer to the readers of “M-K”.
A little about myself: I’m 28 years old, in 1984 he graduated from the Kurgan machine-building Institute, and now work as a Director Zavodoukovskaya station of young technicians.
In recent time become very popular the wheel of the snowmobile. At several Union meetings (most recently in Tyumen) has shown a lot of pneumatic-tired machines: and huge and smaller. Yes, they do not spoil the tundra, but their permeability through the deep and loose snow is not too high: the kind of snow they have a big unit load and, consequently, increased the counter-resistance movement. We have, in the South of the Tyumen region, in the birch and pine forests, snow that is too soft. So I was fascinated by the idea of the sleigh Nezhdanovskoe, which somehow told in “M-K”.
Last year I, along with his brother Alex built a snowmobile under the scheme “caterpillar around skis”, similar to the one which was told in the January issue of “M-K” for the year 1989. And then on the operating experience of this machine, we have designed and constructed an improved type called “Idea-2”, which we present to the readers.
Snowmobile “Idea-2” — truck mount, double, with a crawler gear and asymmetrically located engine.
In short, the following design features. Permeability is lovely: almost any snow — not a barrier. This is not surprising: the specific load on the snow is about 0.02 kgf/cm2. “Idea-2” has besides the increased stability and controllability due to the two pivoting skis with guide parts with undercuts. I also note the simplicity of the drive (due to the asymmetric engine installation), easy start and gear shift, high ground clearance. Asymmetric (the right of the driver) the location of the engine allows the chain drive to the drive shaft of the track and easy to manage motor extra-long levers, gear shift and kick starter.
Engine cooling air. Centrifugal fan with a casing and a duct mounted on the cover of the generator and is attached to the cylinder by springs. The fan drive is via a rubber coupling.
Caterpillar is the most important node of the snowmobile. Here is used the effect of sliding skis on snowy or icy “Shoe” (wooden planks) track. The latter consists of two strips of rubber conveyor belt cross-section of 50X5 mm, to which at equal intervals are attached transverse birch Truckee and rails corners. The connection of the ends of the caterpillar — overlapping with the fixing of the two “tracks”.
Track itself performs several functions: tracks with cleats, sliding surface for supporting the skis and a kind of chain, transmitting movement from the nylon sprocket drive shaft.
Support skiing role is also ambiguous: planar distribution of the load on the snow, a kind of guide track and supporting the sliding surface. In connection with the latest ski necessary to revet capron: it will reduce friction and increase service life of wooden “tracks”.
Reference ski attached to the frame via a rubber bushing that keeps the design flexibility, dampens vibrations and gives the ski a certain mobility in the contours of the land.
The front ski oklepane thin dural sheet, it is still preferable to use a polyethylene sheet. The inclined location of the steering knuckle and guides of the area allow you to freely maneuver on the snow and rolled on the road.
Adjusting the parallelism of the front skis is done using the threaded sleeve on the steering linkage. Details of cladding, floor and bodywork are made from plywood and duralumin. Mounting hinges welded in place.
To facilitate the construction of driving and driven shaft is made of pipes. The movement of the latter adjusts the tension of the belt.
To improve the performance of engine mechanical ignition changed to electronic; reduced combustion chamber.
Snowmobile “Idea-2” is equipped with a headlight and a tail light, a trunk light under the seat. The windshield on it, however installing it is highly desirable.
Fig. 1. Snowmobile
Fig. 1. Snowmobile “Idea-2”:
1 — fuel tank 2 — gear lever, 3 — lever of the starting device of the engine 4 — the bottom wing, 5 — body, 6 — legged ski, 7 — caterpillar 8 — front sprocket, 9 — rear sprocket, 10 — front ski, 11 — knuckle, 12 — mounting bracket supporting skis 13 — shock 14 — the engine of the motorcycle “Minsk” M-103, 15 — muffler, 16 — seat cushion, 17 a frame, 18 — wheel, 19 — transverse thrust of the steering device, 20 — lamp 21 — mounting brackets steering, 22 — adapter 23 — steering column joint, 24 — bronze bushing, 25 — steering column, 26 — a Pitman arm 27 — bronze sleeve-bearing, 28 — mounting bracket of the front of the ski, a 29 — bushing knuckle, 30 — joint cross linkage of the steering gear, 31 — knuckle, 32, a cylindrical pin 33 — bronze bushings.
The frame is welded, it is assembled from “parts” and water pipes, using an industrial machine DC ADZ-150 and electrode Ø 3 mm.
Pipe bending by hand, with a preliminary heating with a blowtorch. T-shaped joints reinforced with gussets.
Mounting plate supporting the skis should be welded after installation the driving and driven shafts and mounting between them the reference of the ski.
Fig. 2. Frame.
Fig. 2. Frame:
1 — support engine mounts, 2 — cross bar (angle steel 30X30 mm), 3 — front cross-member (steel angle 30X30 mm), 4 — pillar steering column (steel tube Ø 20 mm), 5, 6 — bearing seat (steel tube Ø 20 mm), 7 — cross-member — props for setting the reference ski, 8 — frame rails (steel angles 35X35 mm, flange thickness 4 mm), 9 — rear cross bar (steel pipe Ø 22 mm), 10 — Bush steering knuckle 11 — the knuckle bracket.
Fig. 3. The leading axle of the snowmobile.
Fig. 3. Driving axle of a snowmobile:
1 — chain sprocket (from a motorcycle “Minsk”), 2 — bearing housing 3 — bolt, nut and washer (for mounting the crawler sprocket), 4 — crawler sprocket (front) 5 — the tubular drive shaft “bridge”, 6 — flange track sprocket 7 bearing No. 203, 8 — bushing chain sprocket 9 — insert.
Skiing is made of waterproof plywood; bending “socks” is achieved by steaming in boiling water and when the workpiece is fixed on a wooden template. If the front skis are sheathed by dural sheet with aluminum rivets requires the subsequent filing of their protruding “bumps”. The holes in the ski and guides the corners should be drilled in place when installing the mount support, respecting the parallelism of the two guide parts. Then drilled holes and installed the tubular ski sock focus. Reference ski is made similarly.
Engine Assembly with base plates for sure is set at a trailing asterisk after installing on the frame the drive shaft. Primatyvajutsja then welding the base plate to the frame. Full welding of plates is made at the removed engine.
Leverage the kick starter and gear shift are sawn off to size 60 mm, and are welded to them arm, made of pipe Ø 14 mm.
Track mover consists of front drive and rear driven shafts, complete with sprockets and bearings supporting the skis and track.
Fig. 4. Caterpillar snowmobile.
Fig. 4. Caterpillar snowmobile:
1 — bolts, nuts and washers, 2 — conveyor rubber tape, 3 — grouser (birch block), 4 — guide.
On the frame in accordance with spacing and mark the holes for fastening the bearing housing with the drive shaft. Then on the actual size of the track is determined by the place of fastening of the driven shaft. Drilled holes propisyvayutsya the slots for the tensioner shaft back.
Because when welding the possible deformation of the frame, then the manufacturer should monitor the length of tubing to be welded onto machined pivot bearings ends. Also installing the bearings made shaft, it is necessary to align and check the alignment. Then welded the mount plates to a nylon sprocket as per drawing.
When drilling holes for the mounting bolts to nylon sprockets should be accurately aligned last on the tops of the teeth and troughs. After welding and install of the sprockets driving and driven shafts should align. Nylon sprockets are cut according to the template manually, which can be used as saws for metal, saws for wood. Exact fitting and smoothing the surface with a knife Shoe.
Blanks for stars I made out of a nylon pipe Ø mm. 150X20 Cut the piece to the desired length, cut the tube along and heated it with a blowtorch to a plastic state. Squaring the blank, I put it between two smooth boards and pressed from the top weight.
Fig. 5. Crawler unit.
Fig. 5. Crawler unit:
1 — stop (steel rod Ø 10 mm), 2 — sprocket crawler block (nylon with a thickness of 20 mm, Z=8), 3 — flange (steel sheet thickness 3 mm), 4 — tensioning device crawler unit, 5 — sprocket driven (nylon with a thickness of 20 mm, Z=10), 6 — grouser (rake 16X45 mm), 7 — the frame of the snowmobile, 8 — drive sprocket crawler unit (Z=43 from the motorcycle “Minsk”), 9 — strong ski 10 — the bracket supporting the skis 11 — М8Х50 bolt with nut, 12 — М6Х20 screw with nut, 13 — М6Х35 bolt with nut and washer, 14 — guide (brass), 15 — screw 16 — support the sole of the ski (nylon).
Fig. 6. Reference ski.
Fig. 6. Ski reference:
1 — stop (steel rod Ø 10 mm), 2 — bracket, 3 — ski 4 — sole (nylon 4 mm thick), 5 — guide (brass), 6 — rivet (aluminium Ø 5 mm).
Veneer consists of a front flap, gender, body-wing and trunk under the seat.
The seat includes a plywood base, foam cushion and waterproof cover. It is attached to the frame with special hooks and a small bolt.
The gas tank (canister) is mounted on the front panel. Polik is cut from waterproof plywood (in place) and attached with bolts to the frame.
In conclusion, a few recommendations for those who go through our machine. Breaking a few shelves trucks does not affect the patency and does not require immediate repair. Conditions slide “tracks around ski” are saved and rolled the road. Snowmobiling it is possible to have “pusher”, it is easy to tow. For groomed trail the car carries two passengers with cargo 40 kg and towing a skier with a speed of 30 km/h. it is Desirable to have tracks with transverse cleats to improve movement on the slopes.

Brief technical characteristics of the snowmobile “Idea-2”


Type engine power, HP: M-103, 9 L. C.
Type of propulsion: caterpillar
Weight, kg: 90
Bearing area, m2: 1
Specific ground pressure (with driver weight of 80 kg and a weight of 30 kg), kgf/cm2: 0,02
Maximum speed, km/h: 45
Speed on snow, km/h: 35
Speed on loose snow, km/h: 20
Fuel consumption, l/100 km: 8-10
Overall dimensions, mm:
length: 2450
width: 1100
height: 950
The turning radius on the outer ski, m: 3
Maximum angle of elevation, deg.: 30

A. MATVEICHUK, Zavodoukovsk, Tyumen region.

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