SNOWMOBILE-“CARTOP”

SNOWMOBILEImagine readers of the venerable magazine “modelist-Konstruktor” simple in construction and small in size snowmobile, it is available for self-construction. It was designed so that there was no problems with spare parts (for example, there is no single-point lubrication: ball bearings – closed, all sleeves are durable: metallografitovyh and PTFE, and can buy them at any auto shop).

A snowmobile is relatively easy (weight – about 70 kg), the so – called “cartop” (“Kar” car, “top”, top, that is designed to carry on the roof of the trunk or in the passenger compartment of a car). Dimensions “kartopya” for transportation (with the removal of skis and a lowered wheel) is 1450x700x500 mm.
 
A snowmobile designed primarily for anglers ice fishing on the frozen rivers and lakes. It is very maneuverable, which is important for unexpected detour the ice pack and the old holes. Incidental contact with the water supplied with the original recovery system both driver and machine. The system consists of a rescue buoy from the car camera used under normal conditions as part of the driver’s seat, nylon cord (15m) and a spinning reel. The car rises out of the water for this cord.
A snowmobile can be used for movement and to hunters, and lovers stroll on motor vehicles on snow-covered fields and woodlands. However, to operate it at an ambient temperature below minus 25°C and at an altitude of over 1500 m above sea level, and also to overcome the ice pack, snow dumps, etc. is not recommended.
 
SNOWMOBILE
 
Snowmobile
 
Snowmobile-“cartop” “Fisher-2”:
 
1 – managed ski area (2); 2 – rods; 3 – steering knuckle (2); 4 – fuel tank; 5 – lamp; 6 – wheel; 7 – damper; 8 — cylinder; 9 – Carter the built-in chain gear and clutch; 10 – the means of salvation (the camera wheels of the car “the Zhiguli”); 11 – frame; 12 – splash guard (rubber strip); 13 – stretch roller tracks (rubber s20, 2 PCs.); 14 – tensioning mechanism caterpillars; 15 tracks; 16 – support-ski”policles”; 17 – chain transmission (t=12,7); 18 – chain Adjuster; 19 – handle “gas” (from a motorcycle “Voskhod”); 20 – clutch lever; 21 – steering shaft; 22 – sprocket chain transmission (z=11, a motorcycle “Voskhod”); 23 – sprocket driven chain gear (z=43, a motorcycle “Voskhod”); 24 – shield (steel sheet s0,6); 25 – seat; 26 coupling the ring-CZ

 
Chain Adjuster
 
Chain Adjuster
 
Tensioner caterpillar
Tensioner caterpillar
 
Despite the small dimensions, the snowmobile fits and the passenger. It can also go on the Luge toboggan run in the trailer-the Leveller.
 
Before you start talking about the design of the snowmobile, a few words about the history of its creation.
 
Ten years ago, organizing autocross and directing about 30 years section “Buggy” in syut, decided to make a small snowmobile with an engine from a scooter with a volume of 50 cm3 and a power of slightly more than 4 HP And although I already had experience building engines, MT-200, “Sunrise”, minisight demanded a very different approach to both weight savings and compliance dimensions.
 
In the end everything worked out. Was made and tested several miniphantom with different engines and transmissions and it came even to production on one of the enterprises of Academgorodok in Novosibirsk.
 
And now specifically about the design of “Fisherman-2m”.
 
Powerplant snowmobile -brand Krog (analogue Ноndа) of Chinese origin, 1-cylinder (working volume of 210 cm3) 4-stroke, power 6,5 HP with 3600 Rev/min (compression ratio of 8.5), with integrated chain gear with a gear ratio of 1:2 and the automatic clutch in oil bath, with forced air cooling. Starter – manual, the minimum sustainable speed is about 800 per minute, the clutch is triggered at approximately 1400 rpm. Fuel – AI-92, the tank for him a volume of 3.6 liters, enough for 50 -60 km away, or 3-4 hours of work.
 
The power unit is mounted ahead of the spruce side. Steel-engine -compromise solution. In the “technical specification” for “Fisherman-2m” was a hard limit on the length and a little less tough – on mass. To move the engine forward would be to increase the length of 400 mm, and as a result a lot too. When the location of the engine at the rear – you should increase the size of the footprint of the skis and track to save a specified specific pressure.
 
Next to the motor on the right remains an area the size 380×400 mm for feet in shoes 45-th size is sufficient. A slight twist foot to the right when turning to compensate for the overload of the left ski, snowmobile collapses… And the left leg comfortably – attached to the engine it warms…
 
The transmission is a single stage chain transmission with a pitch of 12.7 mm. Pair (master and slave) can change depending on the expected conditions of movement: 16 and 43 tooth (high speed option), 14 and 51 tooth (universal version) or 11 and 51 tooth (traction, heavy duty). In the hollows of the teeth is made small transverse slot for removal of snow, caught under the rollers of the chain. First chain transmission closed cover, but accumulated snow and ice. So contented visor “security”, covering the chain from above.
 
The chain tension is performed by moving the power unit with the screw and nut welded to the bracket on the sub rails.
 
Frame
Frame:
 
1 – spars (30 steel, pipe d25x1,2,2); 2 – front cross member (steel 30 pipe d25x1,2, 2); 3 — the main cross member (steel 30 pipe d25x1,2); 4 – rear cross member (steel 30 pipe d25x1,2,2); 5 – base arc seat pad (Art.3, the pipe d20x1,5,2); 6-Duta back fence of the court (Art.3, the pipe d16x1,5, 2); 7 – front support arc (St.3, the pipe d20x1,5, 4 items); 8 – rear strut (PT.3, the pipe d20x1,5,2); 9 – crossbar pad (Art.3, the pipe d20x1,5, 4 pieces); 10 – rear cross fences (PT.3, the pipe d16x1,5); 11 -sub-frame supporting the skis”pricklish” (Art.3, the pipe 20x20x1,5); 12 – floor subframe (St.3, the pipe d16x1,5); 13 – protective traverse tracks (PT. 3, area 30×30)

 
The frame of the snowmobile – dimensional, welded steel pipes of different diameters: the side members and three cross – tube 25 mm in diameter with a wall thickness of 1-1,2 mm, the upper enclosing part of the tubes diameter 20×1. 5 mm; struts and other supporting details – diameter tubing 16×1 mm, lower frame made of square tube section 20x20x1,5 mm. overall dimensions of frame: length – 1400 mm width – 665 mm, height – 290 mm. And more. Between the inclined pipes of the subframe welded to the floor cross member from the area with shelves 30×30 mm. It performs several functions: first, it protects the mover (a caterpillar); second, it serves as attachment point during transport.
 
In addition, during the installation of components and assemblies to the frame are welded bushings struts steering knuckle and the tip of the steering shaft, under engine skid, different brackets.
 
Engine “caterpillar around ski” I think for light snowmobiles unmatched: patency, low weight, uniform distribution. So I chose this type. Besides homemade caterpillar allows you to adjust the support surface in one direction or another, to change the ratio of length-width. Specific pressure of the tracks was calculated at the beginning of construction of a snowmobile. For low-power snowmobile the normal pressure in the range of 22 -28 g/cm2. Track width (track length) – 580 mm Distance between the tracks (pitch) is 90 mm.
 
Tape tracks (2 pieces) cross-section of 30×7 mm used from a three-layer conveyor belt with nylon threads. Length of the ring is about 1800 mm. Ends are connected by the overlap between two adjacent tracks – speed is small and the imbalance is invisible. If tape is thicker, the ends on the length of the joint you can whittle a wedge with sandpaper or cut to half thickness.
 
The distance between the centers of the drive shaft and the axis of the tension roller carriage caterpillars 720 mm (plus or minus 50 mm at a tension of a caterpillar). For mounting to the frame rails attached to the bearing housings.
 
Node of the drive shaft caterpillars
 
Node of the drive shaft caterpillars
 
Node of the drive shaft of the caterpillar:
 
1 – drive shaft (steel pipe 32 1,5); 2 – inner (welded) flange (steel 30, the sheet s1,5, 2); 3 – drive gear tracks (rubber, sheet s20, 2pcs); 4 – outer flange (сталь30, sheet s1,5, 2); 5 – right tip of the shaft (steel 30, range 29); 6 – bearing 80104 (4x); 7 – cover housing bearing (steel); 8 – bearing housing (steel); 9 – M6 bolt fastening the bearing housings to the frame (4 PCs); 10 – spar frame (furnished); 11 – sprocket chain transmission; 12 – dowel (steel 20); 13 – nut M16; 14 — washer; 15 – the left tip of the control shaft (steel 30, range 29)

 
Drive toothed wheel (star) caterpillars made of rubber from tekhplastiny 20 mm thick (can be from the side of the wheel tractor K-700), it is easily cut with a knife, lubricated with water. Then moved on to nylon gears from the “Buran”, putting the trucks through one tooth, but not much difference felt and then went back to rubber.
 
Calculation and drawing is first made on paper, and made on the Plaza 1:1 for the calculated diameters and degrees. “Of a feather-2” the gears have five teeth with a pitch of 90 mm.
 
The loading of the snowmobile on a car
 
The loading of the snowmobile on the car
 
The main difference from other similar snowmobiles is the reference ski engine. It is made from a set of several plastic (PET) of thick-walled pipes (from 17 to 20, depending on outer diameter), so that reference ski “polistilism”. United pipe in a single design only the front rims of steel sheet and the back – comb (U-shaped profile with prongs on the bottom shelf, which are inserted in each tube). Therefore, each pipe has a relative freedom and can independently be bent slightly when driving on icy ripples or nationname tracks and compacted snow, you have to work like trucks rollers rubber tracks in industrial snowmobiles.
 
Devices supporting the upper branch of the caterpillars (skis or rollers) crawler unit, since the distance between the axes of the gear wheels and idler rollers are small and caterpillar sags slightly. The tension of the caterpillar is made on both sides of the screw and nut that is welded to the bracket on the frame.
The Shoe tracks (of 20 pieces) first made hardwood with quality birch: height to 20 mm and a width of 45 mm (with the same step fastened to the tracks on the tape tracks). Then came a pretty interesting idea to fabricate and install metal: steel tube, pressed into the heated plastic pipe. Steel pipe of diameter 16×1. 5 mm, perhaps extremely small for these purposes. As, however, the length of such tracks (track width) should not exceed 580 mm. Otherwise, it is necessary to strengthen the reinforcement and apply the engine increased power, which inevitably will weight design. Conducted comparative tests of the tracks with the tracks of wood and plastic round pipes, reinforced steel. Reference ski – the same polyethylene pipe, only thick-walled, with anti-friction additives – special order. Here are the results. The advantages of polyethylene are: reliability, long time to move across the ice without lubrication, less weight. Cons: relatively expensive material (almost twenty times), greater resistance to pulling away (compared to a tree with a snow grease and polyethylene in the polyethylene). Flotation on the snow of any thickness are the same, on the ice – wood behave better (with pipes – large drift when turning), “Fisherman” specific pressure on the snow with a load of 100 kg to 24 grams per cm2. The maximum speed is around 22 km/h.
 
The prototype was operated for four seasons. During this time, hitting about 3 thousand km away, Tests showed sufficient reliability and high wear resistance.
 
Knuckle Assembly
 
Knuckle Assembly
 
Knuckle Assembly:
 
1 – front (steel, lap 18); 2 – bearing washer (steel, circle 35 that is welded to the bar); 3 – bottom thrust bearing (bronze, round 35); 4 – heel drive fist (steel, circle 35 that is welded to the hub knuckle); 5 – Bush fist (weldment – steel pipe 25×1,5, welded to the frame); 6 – fry fist (pipe 20x20x1,5, weldment); 7 – small bushing bipod (steel pipe d21x1,5, welded to the fry); 8 – plain bearing (bushing metallografitovyh d18x3); 9 – big Bush bipod (steel, range 35, welded to the bipod); 10-M8 screw; 11-washer; 12 – upper thrust bearing (bronze, round 35); 13 – key (Art.3); 14 – the bearing stand (metallografitovyh sleeve d22x2,2); 15 – front-end longitudinal frame (furnished)

 
The wheel
The wheel
 
Node steering shaft
The node steering shaft:
 
1 — steering shaft (steel 30 pipe d25x2,5); 2 – tip (St.3, round 25); 3-sleeve of the handpiece (30 steel, pipe d25x2,5); 4 – thrust bearing (metallographic, from starter); 5 – fry (trumpet 20х20х 1,5); 6 – axis rods (Art.3, range 12); 7 – clamp; 8 – plain bearing (bronze, circle 30); 9 – bushing the steering shaft (30 steel, pipe d30x2,5); 10 – a clamp-steering wheel; 11 – frame front fender (atmosphere, pipe 16×1,2); 12 – front cross member frame (furnished)

Steering – mixed (motor-car): steering lever shaft turns the wheel, and managed the ski by means of rods (of steel tubes of diameter 16×1. 5 mm) and the steering knuckle. The inclination of the steering shaft from the vertical is 23°, the same inclination and sleeves (respectively, columns) of the steering knuckle. Tilt the front flap – 15°. Comfortable steering wheel position can be selected individually and its slope in the terminal when you build the snowmobile from the transport position into the working.
 
Brakes on “the Fisherman-2” no -coasting (coasting off the “gas”) from a speed 20 km/h is small, less than 4 m. But it is easy to mount a Bicycle saddle, attaching it to the disc on the output shaft of the engine.
 
Reference-ski
 
Reference-ski
 
Reference ski-“policles”:
 
1 – element “pricklish” (polyethylene or polypropylene pipe d22x3, compl.); 2 – bandage (steel sheet 1,5 s); 3 – “comb” (steel sheet 1,5 s); 4 – stretcher; 5 – bracket “pricklish” to the subframe (pipe 20x20x1,5,4 pieces); 6 – solitaire (steel sheet 1,5 s); 7 – spar frame (furnished)

 
Rear
 
Rear “comb” reference runners”pricklish”
 
Knot stretch axis
 
Node stretch axis
 
Controlled skiing on a snowmobile (in transport position)
 
Controlled skiing on a snowmobile (in transport position)
 
Caterpillar
 
Caterpillar
 
Caterpillar:
 
1 – tape 30×7 (from the conveyor belt with nylon cord, 2); 2 – Trak (24×4 plastic pipe, reinforced steel tube 16×1,5 (kompl.); 3 – retaining clip (plastic tube 24×4, reinforced steel tube 16×1 (kompl.); 4 – bolt of M6 with nut and washer extended (kompl.); 5 — “policles” (furnished); 6 – frame (furnished); 7 – pipe “pricklish”

 
Controlled skiing
Guided ski:
 
1 – body (steel sheet s0,6); 2 – snake (steel 40X, sheet E1,5,2); 3 – undercut (steel 40X, sheet s2, 2); 4 – pylon (steel 40X, sheet s1,5, 2 PCs.)

 
Recovery system (seat removed)
 
Recovery system (seat removed):
 
1 – a casing of a caterpillar (Seating); 2 – shell (lock camera), welded to the casing; 3 — spinning reel; 4 — an arm of fastening of the coil to the snowmobile; 5 – nylon cord

 
Ski guides are made of sheet steel of different thickness: the runners (steel 40X) and control horns from 1.5 mm sheet, embossed curved top – to 0.6-mm undercuts, and the skids, from “stainless steel”, only 2 mm thickness (ridge height of 15 mm, shifted back to stabilize). Individual elements of the ski are combined in a single design of contact welding.
 
The snowmobile is equipped with a hitch to tow a sled trailer weight up to 250 kg or industrial plastic sledge toboggan run (toboggan type) size 1600×900 mm (cost 3 thousand rubles.) with a load up to 100 kg. the Trailer can be used for towing the snowmobile manually, in case of breakage. But first, we made a homemade scraper from a steel sheet by the width of the truck length like a caterpillar unit. It is relatively little, but for the fishing gear is enough. For fastening of Luggage there is four holes on the sides.
 
Due to the dense arrangement of the original “poliklinikou” mover minisight “Fisherman-2M” has the best maneuverability in its class. Check-in and passage is not required.
 
During the operation there were thoughts on improving snowmobile:
 
1. Cover-casing to make the flip to clean the snow and ice before loading into the car for transportation.
 
2. The floor under my feet to lay out the “notch” that is not going to snow.
 
3. Weld the front to traverse the tow ring.
 
4. Install the engine more powerful.
 
5. To mount the intermediate shaft with subchorionic transmission.
 
6. And, finally, to make a collapsible version of the snowmobile.
 
But it will be a different car.
 
V. FEDOTOV, p. Suzun, Novosibirsk region.

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