What do the lengths and weights of rotors determine in an engine?

• A. The capacity of the fuel system
• B. The number of bearings required
• C. The speed of the engine
• D. The efficiency of the cooling system

Answer: (B)

The lengths and weights of rotors in an engine are critical in determining the number of bearings required to support them. Bearings serve the essential function of reducing friction and providing stability to rotating components. The physical characteristics of the rotors, such as their length and weight, directly influence how many bearings are necessary to adequately support the rotors and ensure smooth operation.

For example, longer or heavier rotors will exert more force or have different load distributions, which might require additional bearings for proper support and to prevent deformation or failure. Understanding this relationship is vital for the design and operation of aircraft engines, as it directly affects their reliability and performance. Other options relate to aspects such as fuel capacity, engine speed, and cooling efficiency, which are influenced by different factors not directly connected to the lengths and weights of rotors.