Static Loads

W_fs= Wc/L

W_rs= Wb/L

W_fs = Static weight on front axle

W_rs = Static weight on rear axle

Dynamic Loads

• Grades (θ)

W_f = W_fs – Whθ/L

W_r = W_rs + Whθ/L

W_f = Dynamic weight on front axle

W_r = Dynamic weight on rear axle

• Accelerating

W_f = W_fs – Wha_x/(Lg_c)

W_r = W_rs + Wha_x/(Lg_c)

a_x = acceleration in X-direction

g_c = acceleration of gravity

 

Acceleration relation

F_x = M.a_x = Wa_x/g_c

P = F_x.V

a_x = F_x g_c/W = Pg_c/(VW)

a_x / g_c = P/(VW)

Acceleration is

1. Proportional to power to weight ratio.
2. Inversely proportional to speed.
3. Efficiency in utilizing available power depends on

• Minimizing friction losses and
• Ability to keep engine at peak power.