FAA Powerplant Written Practice Test

How are cylinders typically attached to the crankcase in an aircraft engine?

1. By welding

2. By mounting them directly to the crankshaft

3. By studs mounted in threaded holes in the crankcase

4. By a locking mechanism external to the crankcase

The correct answer is: By studs mounted in threaded holes in the crankcase

Cylinders are typically attached to the crankcase in an aircraft engine using studs mounted in threaded holes in the crankcase. This method provides a secure connection that can withstand the stresses and forces experienced during engine operation, including vibrations and thermal expansion. The studs allow for precise alignment of the cylinders with the crankcase, ensuring that they fit snugly and maintain proper sealing, which is crucial for the efficiency and functionality of the engine. The use of threaded studs also makes it easier to disassemble the engine for maintenance and repairs, as the cylinders can be removed without damaging the crankcase or other components. This approach is preferred in aviation applications, as it contributes to both the robustness and serviceability of the engine design.