15.依SOLAS救生艇推進之規定，救生艇引擎能於救生艇未下水時，由冷機啟動後運轉至少幾分鐘不致損壞？ (A)3 (B)5 (C)7 (D)10

10.Longitudinal vibration of propulsion shafting systems is often excited by the variable thrust developed by the propeller due to the non-uniform wake pattern in which it operates. The predominant periodic component of the thrust developed by a propeller occurs at blade-rate frequency, i.e., the number of propeller blades times the rotational frequency of the shaft. For a four-blade propeller running at 60 rev/min, what is the predominant periodic frequency that excites the longitudinal vibration of the propulsion shafting systems? (A)1 Hz (B)2 Hz (C)3 Hz (D)4 Hz

15.依SOLAS救生艇推進之規定，救生艇引擎能於救生艇未下水時，由冷機啟動後運轉至少幾分鐘不致損壞？
(A)3
(B)5
(C)7
(D)10

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15.依SOLAS救生艇推進之規定，救生艇引擎能於救生艇未下水時，由冷機啟動後運轉至少幾分鐘不致 損壞？ (A)3 (B)5 (C)7 (D)10

相關試題

相關試卷

15.依SOLAS救生艇推進之規定，救生艇引擎能於救生艇未下水時，由冷機啟動後運轉至少幾分鐘不致損壞？
(A)3
(B)5
(C)7
(D)10