🔍 Key Concepts

• Difference between indicated horsepower, shaft horsepower, and brake horsepower • How engine power can be measured directly vs. calculated from cylinder pressures • Where in the power train (inside the cylinder vs. at the shaft vs. on a test bed) each horsepower term applies

💭 Think About

• Ask yourself: Does 'indicated' suggest something measured at the propeller shaft, or something obtained from indicator diagrams/pressure inside the cylinders? • Which option describes power that is actually delivered to the shaft, and which one is based on calculations/theory rather than direct mechanical measurement? • Think about what a dynamometer measures and where a test bed is used—are those associated with indicated horsepower or with other horsepower terms?

✅ Before You Answer

• Identify which term refers to power inside the engine cylinder before mechanical losses • Confirm which term refers to power available at the shaft after mechanical losses • Verify that indicated horsepower is linked to engine indicator diagrams and cylinder pressure, not to a device attached to the shaft like a dynamometer