TRACTOR HOUSEThis mini tractor was built in a family of Amateur design Bureau of Paul: under the guidance of the head of the family of Valery Vasilyevich machine was assembled by his sons Sergei and Andrei. All three are longtime readers of the magazine “modelist-Konstruktor”. Small-sized tractors, called by its creators the acronym SAP (S. A. Paul), is designed as a universal – tilling and transport agricultural unit. He can plow, cultivate, harrow, and to tow a cart with goods or a small tank with a capacity of about 100 litres for watering the infield.

The car was very successful -it is economical, maneuverable and has a high permeability. Has eight gears – four forward and four back. Maximum speed 37 km/h.
Frame mini-tractor welded, is a “horseshoe”, the bent of thick-walled drill pipe with a diameter of 28 mm, the two parts of the strut and the original pipe with a diameter of 50 mm. Two steel notched plates in the rear part intended for fastening the intermediate sprockets. The use of the elements of the frame of the scooter T-200 has facilitated the installation of the engine and a portion of the lining of the hood.
Front axle. Its basis is a beam of welded pipes with a diameter of 42 mm, in the form of the letter N. The welds are reinforced with steel gussets. In bushings of the axles pressed bronze liners. The abutment of the front axle with the frame consists of two rails with a steel bushing between them.
Knuckles is a chiseled speed roller with welded thereto a steel sleeve (it is inserted into the front driveshaft). The rotary levers of a steering trapeze serve as the pedals off of a moped “Riga”.
Microtracker SAP
Microtracker SAP:
1 – the driver’s seat; 2 – control unit; 3 – the handle of a cover of a cowl; 4 – a headlight lighting; 5 – front bumper; 6 – the control of gearshift and clutch control; 7 – the lever of kick starter; 8 – reverse lever; 9 – a brake pedal; 10-gas pedal

Front axle
Front axle:
1 – hinge joint of front axle; 2 – beam peredney bridge; 3 – bracket of the front mud flap; 4 – axle sleeve; 5 – axis; 6 – the front wheel hub e of the brake device; 7 – axle; 8 – pivot arm

Steering. The basis of it is the steering gear – gear reducer with conical gears (gear ratio – 1:3) from a chainsaw “Friendship”. A smaller gear is connected with a steering wheel, and the shaft is worn more potatoes, then force through a longitudinal thrust is transmitted from the Pitman arm on the lever is welded to the left axle.
Transmission. Torque to the driving sprocket of the motor with roller chain is transmitted to the main differential gear with a reversing device (motorized С3Д) and the hub mounted on the axle of the wheels.
Rear axle. This is the most complex Assembly of mini-tractors, so it makes sense to describe its design in more detail. It consists mostly of parts from scrapped cars, and the main challenge in the layout was the most successful of their joint.
The hub of the wheels from the GAZ – 69. For mounting them on the driven sprockets regular studs were replaced with bolts, respectively, and refined, the seats are drive wheels. That rear axle was more compact, the wheels turned, the inner part was outer.
Frame microfracture
Frame microfracture:
1 – fixing unit of the engine; 2 – horseshoe (drilling steel pipe with a diameter of 28 mm); 3 cross-member (steel angle 30×30 mm); 4 – bracket; 5 – cross bar (angle steel 40×40 mm); 6 – shaped bracket for mounting drive shaft (steel sheet thickness 12 mm); 7 – cross bar (steel pipe 50 mm in diameter); 8 – bolt M16

Bearing Assembly drive sprocket
The bearing sprocket:
1 – shaft; 2 – Circlip; 3 – gland; 4 body mount drive shaft; 5 — drive sprocket; 6 – nut: 7 – sleeve; 8 – ball bearing No. 205

Brake drums rear wheel of the scooter VP-150. For attachment to the wheel hub they bolt drilled five holes with a diameter of 10 mm. the Driven sprocket is attached directly to the brake drums.
The body of the brake pad from scooter “Tourist”. For attachment to the bearing housing in the large center hole of 52 mm in diameter and drilled for bolts three holes with a diameter of 10 mm.
Bushing housing brake pads and the node through which the axle shaft is installed into the frame, were made independently.
The most complex and critical components and parts of the tractor shown in the figures.
Kinematics of steering:
The kinematics of steering:
1 – steering mechanism; 2 – potato; 3 – longitudinal thrust; 4 – transverse thrust; 5 – knuckles

Rear axle microfracture
Rear axle microfracture:
1 – axle shaft; 2 – a wheel hub (GAZ-69); 3 – drive wheel (from the GAZ-60 or UAZ-469); 4 – brake drum (from a motor scooter Vyatka VP-150); 5 – counter shaft sprocket; 6 – a plate of fastening of the axle shaft; 7 – a bolt with nut (for fixing the bearing housing); 8 – bearing housing; 9 – packing gland; 10 – a cover of a bearing housing; 11 – sleeve; 12 – the case of the brake pads; 13 – brake pad; 14 – flange
Mini tractor was operated for many years, with no accidents or issues just not there. Machine worked successfully in the coupling with two-wheeled trailer, and plow. Without much difficulty it can be installed and screws.
The tractor has good permeability not only in summer but in winter for movement in deep snow the front wheels are replaced by skis. Similarly transformered and trailer of two-wheeled cart becomes dublenoj.

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