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 mechanical efficiency of the airplane.
(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
Want to see more full solutions like this?
Chapter 14 Solutions
Vector Mechanics for Engineers: Dynamics
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY