Experimental evaluation of traction and coupling properties of snowmobile motor vehicles

The article demonstrates the results of the experimental estimate of the drawbar properties of the oversnow equipment during which parameters and indicators allowing for their use during designing of new generation of oversnow vehicles have been determined. This work demonstrates the results of the tests in determining maximum drawbar pull, determining motion resistance force with the arrested and released brake of the Russkaya Mekhanika's oversnow vehicles, models RM Buran Leader, RM Tayga Varyag 550, RM Tayga Patrul 800 SWT, RM Vector 551i and over companies' oversnow vehicles, models BRP Lynx Xtrim Commander 800 E-TEC, Arctic Cat Pantera 7000 XT LTD, Polaris 800 Titan Adventure 155.


Place of test
The tests to determine drawbar properties of the oversnow equipment were conducted in vicinity of Rybinsk, Yaroslavl oblast, Russia at the horizontal terrain sections with the maximum slope of 1%.
During the test: The test site was covered with compacted snow 5 to 7 cm deep, the snow was uniform along the entire depth, with a temperature of minus 6 °С.
The tests were conducted in dry windless weather at an ambient temperature of minus 6 ºС, atmospheric pressure of 748 mm Hg and air relative humidity of 86 % [1-3].

Measuring equipment
Weight measuring strain gauge С2-5.0-С3 and digital tension gauge ZET were used as measuring instruments to determine the oversnow drawbar properties including maximum drawbar pull and motion resistance force [4].
Digital dynamometer С2-5.0-С3 represents a stain gauge-based device.The strain gauge is connected in series with the power diagram.Dynamometer С2-5.0-С3 is composed of a weight measuring strain gauge working in tension and compression, a secondary measuring converter and a connecting cable.Model ZET is used in dynamometer as a secondary measuring converter.
Dynamometers with measuring terminal ZET operating through interface ZET 7174 converter are delivered with software ZETLAB used to present those measurements in the form of real-time measurement process charts.

Determining maximum drawbar pull
The maximum drawbar pull was determined for the Russkaya Mekhanika's oversnow vehicles, models RM Buran Leader, RM Tayga Varyag 550, RM Tayga Patrul 800 SWT, RM Vector 551i and over companies' oversnow vehicles, models BRP Lynx Xtrim Commander 800 E-TEC, Arctic Cat Pantera 7000 XT LTD, Polaris 800 Titan Adventure 155 equipped with caterpillar tracks with snow grip from 10 to 45.7 mm.
The maximum possible drawbar pull of the oversnow vehicle (within the pull force margins) was determined with the CVT being in first gear range.With that the tested oversnow vehicle was accelerated to reach maximum RPM, and then smoothly slowed down via a cable with a dynamometer stain gauge to a full stop when a tracked running gear was fully slipping [5,6].
The results of the drawbar pull measurement are presented in Table 1.
The motion resistance force was determined by the tested vehicle towing method.The oversnow vehicle was towed with a cable with strain gauge С2-5.0-С3 at a speed of 1 m/s by an oversnow vehicle or 4-wheeler, with that the transmission of the tested oversnow vehicle was in neutral gear and brakes either: case 1 -released; case 2 -applied [7].

Determining the oversnow vehicle's motion resistance force with the brakes released
Table 2 contains the results of measurement of the oversnow vehicle's motion resistance force with the brakes released.

Outcomes
The RM Buran Leader oversnow vehicle's maximum drawbar pull stood at 1850 N. The RM Tayga Varyag 550 oversnow vehicle's maximum drawbar pull stood at 2750 N.
The RM Vector 551i oversnow vehicle's maximum drawbar pull stood at 3092 N.
The BRP Lynx Xtrim Commander 800 E-TEC oversnow vehicle's maximum drawbar pull stood at 3786 N.
The Arctic Cat Pantera 7000 XT LTD oversnow vehicle's maximum drawbar pull stood at 3841 N in low gear and 5978 N in super low gear.
The Polaris 800 Titan Adventure 155 oversnow vehicle's maximum drawbar pull stood at 3590 N.
The RM Buran Leader oversnow vehicle's maximum motion resistance force stood at 950 N with the brakes released.

Table 1 .
Results of maximum drawbar pull measurement

Table 2 .
Results of measurement of the oversnow vehicle's motion resistance force with the brakes released

Determining the oversnow vehicle's motion resistance force with the brakes appliedTable 3
contains the results of measurement of the oversnow vehicle's motion resistance force with the brakes applied.

Table 3 .
Results of measurement of the oversnow vehicle's motion resistance force with the brakes applied