Enter the crankshaft radius (in), the length of the piston rod (in), and the angle of the crankshaft (degrees) into the Piston Position Calculator. The calculator will evaluate the Piston Position. 

Piston Position Formula

The following formula is used to calculate the Piston Position. 

P = r*cos(a) + SQRT ( b^2-r^2*sin(a)^2)

Variables:

  • P is the Piston Position (in)
  • r is the crankshaft radius (in) 
  • b is the length of the piston rod (in) 
  • a is the angle of the crankshaft (degrees) 

How to Calculate Piston Position?

The following steps outline how to calculate the Piston Position.


  1. First, determine the crankshaft radius (in).
  2. Next, determine the length of the piston rod (in). 
  3. Next, determine the angle of the crankshaft (degrees). 
  4. Next, gather the formula from above = P = r*cos(a) + SQRT ( b^2-r^2*sin(a)^2).
  5. Finally, calculate the Piston Position.
  6. After inserting the variables and calculating the result, check your answer with the calculator above. 

Example Problem:

Use the following variables as an example problem to test your knowledge.

crankshaft radius (in) = 3

length of the piston rod (in) = 7

angle of the crankshaft (degrees) = 40

P = r*cos(a) + SQRT ( b^2-r^2*sin(a)^2) =  ?