Efficiency of Timber Jack 450C with different loading volumes in different slopes.

Primary transportation is an upper time, expensive and hard labour. The most skidding are with using of rubber wheel of Timber jack 450C in Iran country that has devoted 60% of utilization expenses. In order to, investigate of slope and loading volume effects on time of loaded traveling had used time study for Timberjack 450C. In one of strip roads in parcel eleven of district two of Langa management plan forest (Kelardasht region in North of Iran) determined 5 and 3 different slopes classes and volumes classes, respectively. Then, time study was performed in slope classes with different loading volume in downward skidding. The first, collection of data have noted in special form and then have converted to uniform unit of m sec(-1). Descriptive statistics for each data set were calculated using the SPSS software. With presupposition that loading volume and slope are effective on the obtained time, these parameters have analyzed. ANOVA and Tukey test were used for loading volume factor. For investigation slope factor had used of Mann Whitney non-parametric test in order to comparison of loaded traveling speed in different slopes. Results of present research had showed that influence of loading volume on the loaded traveling time is insignificant, but loaded traveling speed in different slope classes is significant (in slopes >30%) as, speed of skidder machine is decreased with increase of slope variable.