🔍 Key Concepts

• Side thrust on a crosshead is created by the angularity of the connecting rod relative to the cylinder centerline. • Side thrust will be largest when both cylinder pressure is high (power stroke) and the connecting rod angle is greatest. • In each figure, note whether the engine is on compression, power, or exhaust, and the crank angle relative to top dead center (TDC).

💭 Think About

• In which figures is the piston being pushed downward by gas pressure rather than driven upward by inertia or compression? • Looking at the crank position in each figure, where does the connecting rod form the largest angle from the vertical cylinder axis? • Combine those two ideas: which figure shows a large connecting-rod angle at a time when pressure on the piston crown would still be high?

✅ Before You Answer

• Identify which figures are clearly near TDC on the power stroke versus compression or exhaust. • Compare the obliquity of the connecting rod (how far it leans from vertical) in those power‑stroke figures. • Before choosing, verify that in your chosen figure there is both significant gas load on the piston and maximum rod angularity, as this gives maximum crosshead side thrust.