Power, Vx & Vy, Aerodrome Distances (15-05-18) Flashcards
What is the equation for power required?
Power required = Drag x TAS
What does a tangent to the power required curve through the origin show?
VMD
What can be seen from the power mega graph?
Max speed jet
Max speed prop
Vy jet
Vy prop
VMP (speed of max endurance prop)
VMP (speed of max range prop)
What is VY and when does it occur?
The speed for best rate of climb and it occurs when the amount of excess power available is biggest.
What determines the ROC in terms of power?
The size of the gap between power required and power available.
What speed in relation to VY does a jet need to fly to gain it’s benefit?
Within 10%, but it is rarely used IRL.
What speed does VY occur at for a prop?
VMP
What is best endurance speed sometimes referred to as?
Holding speed.
Out of Vx and Vy, what will achieve the higher altitude for a given horizontal distance?
Vx
Out of Vx and Vy, what will achieve the higher altitude for a given amount of time from TO?
Vy
When flying for fuel efficiency what speed is preferred out of Vx and Vy and why?
Vy because at high altitude fuel flow is low so you want to get high ASAP.
Why does fuel flow reduce with altitude?
For peak efficiency a certain fuel to air ratio is desired so with there being less air at altitude, there must also be less fuel flow.
What happens to rate of climb and angle of climb with an increase in altitude, mass or flap?
They decrease.
What happens to Vx and Vy with an increase in altitude at constant IAS?
Vx is unaffected
Vy gets slower
What happens to Vx and Vy with an increase in altitude at constant TAS?
Vx increase
Vy increases