🔍 Key Concepts

• Study how the control piston moves horizontally and how that motion is transferred through the lever arms to the camshaft segments. • Think about mechanical advantage: when levers are used, does the driven part usually move more, less, or the same distance as the input part? • Consider the purpose of this reversing unit on a slow-speed diesel: is it tied to propeller pitch, or to changing the timing and direction of the engine cams?

💭 Think About

• Compare the straight-line travel of the control piston with the rotational/limited movement of the camshaft blocks shown in the front and top views. How do their paths and distances differ? • Ask yourself whether the air requirements to move this piston would logically depend on engine speed, or only on control air pressure and piston area. • Look at what this unit is actually connected to: does the drawing show any mechanism for changing blade pitch, or only for shifting cam positions for ahead/astern running?

✅ Before You Answer

• Verify from the sketch which element is the control piston and which parts are the camshaft levers/segments. • Check whether the geometry of the levers would make the piston stroke longer or shorter than the resulting movement at the camshafts. • Confirm from the illustration that this unit is associated with camshaft position for reversing, not with a controllable pitch propeller system.