Aircraft Performance Multiple Choice Questions on “Minimum Fuel Climb”.
1. Which of the following is the formula for specific climb?
a) SC=(frac{dH}{Q_f})
b) SC=(frac{dH}{dt})
c) SC=(frac{dH/dt}{Q_f})c
d) SC=(frac{dH/dt}{Q_f})
Answer: c
Clarification: The formula for specific climb is given by SC=(frac{dH/dt}{Q_f}) where SC is specific thrust, (frac{dH}{dt}) is rate change of height with respect to time and Qf is fuel flow. The specific climb is calculated in the units of ft/kg.
2. The unit of specific heat is ft/kg.
a) True
b) False
Answer: a
Clarification:The formula for specific climb is given by SC=(frac{dH/dt}{Q_f}) where SC is specific thrust, (frac{dH}{dt}) is rate change of height with respect to time and Qf is fuel flow. The specific climb is calculated in the units of ft/kg.
3. What is the value of specific climb when the value of (frac{dH}{dt})=1 and the fuel flow is 833.33 kg?
a) 0.0013ft/kg
b) 0.0012ft/kg
c) 0.0019ft/kg
d) 0.002ft/kg
Answer: b
Clarification: The answer is 0.0012ft/kg. The formula for specific climb is given by SC=(frac{dH/dt}{Q_f}). Given, (frac{dH}{dt})=1 and Qf=833.33 kg. Substituting the values we get SC=(frac{1}{833.33}).
We get SC=0.0012ft/kg.
4. Which of the following characteristics are determined during flight trials of calculated fuel flow?
a) Fuel rate
b) Optimum climb speed
c) Airspeed
d) Altitude
Answer: b
Clarification: During the calculated fuel flow flight trials the optimum climb speed is calculated and then the specific climb function is known which helps in the determination of airspeed for a minimum fuel climb.
5. The minimum fuel climb occurs at the airspeed for best rate of climb.
a) True
b) False
Answer: a
Clarification: The minimum fuel climb occurs at the airspeed for best rate of climb. During the calculated fuel flow flight trials the optimum climb speed is calculated and then the specific climb function is known which helps in the determination of airspeed for a minimum fuel climb.
6. The thrust reduction during climb leads to ____________
a) increase in rate of climb
b) reduction in time of flight
c) increase in gradient of climb
d) decrease in climb gradient
Answer: d
Clarification: The thrust reduction during climb leads to reduction in rate and climb gradient and increases the time taken for the take-off of the aircraft. The minimum fuel climb occurs at the airspeed for best rate of climb.
7. What are the factors that affect the economic benefits of fuel climb?
a) Indirect operating costs
b) Direct operating costs
c) Annual pay to the airport
d) Tax pay
Answer: b
Clarification: The analysis of the economic benefits of a minimum climb will depend on the direct operating costs of the aircraft. Direct operating costs include the costs that are directly related to the operation of the flight during travel such as crew salary, seat cost, fuel costs etc.
8. In practical the specific fuel consumption is effected by the airspeed, mach number and temperature.
a) True
b) False
Answer: a
Clarification: In practical the specific fuel consumption is effected by the airspeed, mach number and temperature. These factors will optimize the minimum fuel climb of the aircraft. The analysis of the economic benefits of a minimum climb will depend on the direct operating costs of the aircraft.
9. In the calculation of the specific climb the specific fuel consumption is kept varying and the thrust or power is kept at maximum position.
a) True
b) False
Answer: a
Clarification: In the calculation of the specific climb the specific fuel consumption is kept constant and the thrust or power is kept at maximum position.The formula for specific climb is given by SC=(frac{dH/dt}{Q_f}) where SC is specific thrust, (frac{dH}{dt}) is rate change of height with respect to time and Qf is fuel flow. The specific climb is calculated in the units of ft/kg.
10. Engines with low noise signature comply with the noise regulations and provide a better performance in the climb.
a) True
b) False
Answer: a
Clarification: Engines with low noise signature comply with the noise regulations and provide a better performance in the climb. This is because they can operate at higher thrust levels without exceeding the noise limits.