Performance + IR Flashcards
What is the “angle of climb”?
Angle of climb is the angle between the flight path of the aeroplane and the horizontal, relative to the airmass in which it is travelling. Thus, it is not affected by wind.
What is the angle of climb flight path?
The angle of climb flight path is the angle between the flight path of the aeroplane and the horizontal relative to the ground. Thus, it is influenced by wind. During a headwind the angle will be steeper, and shallow during a tailwind.
What is the climb gradient and gradient of climb flight path?
Climb gradient is the ratio between the horizontal distance travelled and the altitude gained within an airmass. The gradient of climb flight path is similar but relative to the ground. Thus, affected by wind. The angle will be steeper during a headwind, vice versa during a tailwind.
What is Vx, and what would it look like on a graph?
Vx is the best angle of climb speed, or the speed at which the greatest altitude can be gained for the least amount of horizontal distance. On a graph, Vx can be achieved where thrust available and thrust required is farthest apart.
Vx is affected by wind
What is Vy, and what would it look like on a graph?
Vy is the best rate of climb speed, or the speed at which the greatest altitude gain can be achieved in the shortest amount of time. Vy will on a graph where the power required and power available curves are farthest apart.
Vy is not affected by wind.
What is the angle of descent and the angle of descent flight path?
The angle of descent is the angle between the flight path of the aeroplane and the horizontal, relative to the airmass in which it is travelling.
The angle of descent flight path, is the angle between the flight path of the aeroplane and the horizontal, relative to the ground. Thus, influenced by head or tailwind.
What is the descent gradient and the gradient of descent flight path?
Descent gradient is a ratio between the amount of distance travelled to altitude lost, within an airmass. Gradient of descent is the same, but relative to the ground. Thus, affected by wind.
Define aeroplane centre of gravity, and the effects of a too far forward CG.
An aeroplane’s centre of gravity is that point where the aeroplane would balance if the aeroplane was suspended at that point. The CG is mostly located ahead of the centre of pressure to ensure a nose down tendency if an engine failure occurs. However, to keep the nose pitched up, one will require a downforce from the elevator. Since lift must oppose weight and this downforce, one would require more lift to remain in equilibrium. The farther forward the CG, the more downforce required which equals more lift required, ultimately reducing overall aircraft performance.
How can an inoperative anti-skid system affect landing?
If the anti-skid system does not work as intended, the wheels may lock upon landing when braking hard. On a wet runway, the aeroplane will skid out of control.
Define the absolute ceiling
The absolute ceiling is where the power required and power available lines become tangent, no further climb can be achieved. 0 FPM
Define the service ceiling
The service ceiling, is where the aeroplane can still achieve a climb of 100fpm. 50 fpm for one engine inoperative
determining the various cruise techniques, define maximum range cruise(MRC)
As the name implies, this entails operating the airplane at the the speed for best range (Vrmax), which will provide the maximum amount of distance for given amount of fuel and is also considered to provide the lowest fuel cost.
Explain Thrust Required and Thrust Available
Thrust required is directly proportional to total drag, total drag is induced drag and parasite drag combined. It is the force required to overcome drag.
For a propeller driven aeroplane, thrust available is dictated by propeller efficiency. At lower airspeeds we will have more thrust available from the propeller since it will be at a higher angle of attack, and less thrust as airspeed increases due to the the lower angle of attack.
If we look at the performance graph the thrust required curve will be that of a bowl shape, due to induced drag and lower airspeeds and parasite drag at higher airspeeds.
And thrust available a curve that decreases with airspeed.
Best rate of climb can be achieved at?
The airspeed where the difference between power available and power required is maximum.
Best angle of climb can be achieved at?
The airspeed where thrust available and thrust required is maximum
