Concept explainers
While cruising in level flight at a speed of 570 mi/h, a jet airplane scoops in air at a rate of 240 Ib/s and discharges it with a velocity of 2200 ft/s relative to the airplane. Determine (a) the power actually used to propel the airplane. (b) the total power developed by the engine, (c) the
(a)
The power used to propel the airplane.
Answer to Problem 14.80P
power =
Explanation of Solution
Given information:
Flight speed
Exhaust relative to the plane
Mass flow rate =
From the relation of principle of impulse and moment:
Calculation:
Power used to propel the airplane:
(b)
The total power developed by the engine.
Answer to Problem 14.80P
Total Power =
Explanation of Solution
Given information:
Flight speed
Exhaust relative to the plane
Mass flow rate =
From the relation of principle of impulse and moment:
Calculation:
Power used to propel the airplane:
Power of kinetic energy of the exhaust:
Now, total power of the airplane,
(c)
The mechanical efficiency of the airplane.
Answer to Problem 14.80P
Total Power =
Explanation of Solution
Given information:
Flight speed
Exhaust relative to the plane
Mass flow rate =
From the relation of principle of impulse and moment:
Calculation:
Power used to propel the airplane:
Power of kinetic energy of the exhaust:
Now, total power of the airplane,
Mechanical efficiency to propel the airplane
Mechanical efficiency
Mechanical efficiency
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Chapter 14 Solutions
Vector Mechanics For Engineers
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