MEP1 - Performance Data Flashcards
What would be the effect of the operative engine during engine failure and a nose high attitude?
Since the engine is now at an incline angle, the down-going propeller will strike the airflow at a larger angle of attack than the up-going blade, which results to unequal thrust produced by the propeller.
Define arm and moment
The term “arm” refers to the distance of an object from a reference datum, and the term “moment” is the effect of a force due to the length of the arm.
Define “Critical Engine”
The power unit which, if failed completely, would have the most adverse effect on the performance characteristics of an aeroplane.
If one engine fails, what would be the effect of increased yaw?
The greater the yaw, the higher the minimum control speed(Mca). Any increase in yaw, which increases drag, will adversely affect perfromance.
What would happen to rudder effectiveness during a one engine failure?
As with all flying controls, effectives is determined by the amount of air flowing over the control surface. If the airspeed continually decrease with one engine failure, the rudder might lose the ability to correct the added yaw. Every multi-engine airplane does have a specified minimum control airspeed, where rudder effectiveness remains adequate. Called Vmca
At what speed, with a fixed pitch propeller, does the propeller produce the most thrust?
At the slowest possible speed, or stationary. As the speed of the aeroplane increases, the relative airflow strike the propeller at a different angle, decreasing the angle of attack.
How would a reduction in air density require a higher IAS to meet required Vspeeds?
A reduction in air density also mean a higher TAS will be required for the same amount of IAS. Meaning, if we want to achieve a specified Vspeed, Vr for example, can only be achieved at a higher true airspeed speed at high altitude compared to low altitude.
As per regulations, what are the maximum allowable percentage of the forecasted wind speed that may be used when calculating take-off distance required?
For a headwind, only 50% of the forecasted wind speed may be used, and only 150% of the tailwind.
The effect of wind on the climb gradient?
The pilot should note that the climb gradient extracted from the performance graphs is in relation to the airmass within which the aeroplane is travelling. With zero wind, the greatest climb gradient will be achieved at Vx. With a headwind, the angle of climb will increase, one would gain more altitude in a given distance. The opposite effect will occur with a tailwind. If the extracted climb gradient is not satisfactory, a steeper one will be required, or if this is not possible, take-off mass need to be reduced. Referred to as the obstacle limited take-off mass.
Cruise Techniques:
Define MRC:
MRC is the maximum range cruise, and as the term implies, this entails operating the aeroplane at the speed Vrmax which will deliver the maximum range on a given amount of fuel and is also considered to provide the lowest fuel cost for a given distance.
Cruise Techniques:
Define LRC:
LRC is the long range cruise, and this is achieved at a slightly higher speed, between 3% and 5% higher than Vrmax. Which means the flying time will be less, but the range will also be slightly less then MRC.
Cruise Techniques:
Define Economy Cruise:
Economy cruise is concerned with overall operating costs and not just the fuel costs.
Cruise techniques:
Define High Speed Cruise:
For normal passenger transport operations this speed is not economically viable However it can be used in a situation where time is more important than economy.
Cruise techniques:
Define Maximum Endurance Speed:
In terms of cost effectiveness, operating at this speed is of no use for normal passenger transport operations. Flying for endurance is more concerned with the minimum possible fuel consumption, rather than distance travelled.
Factors affecting glide angle:
Does mass affect the glide angle?
Any variation in mass does NOT affect the glide angle, as it depends on the ratio of lift to drag, which is independent of weight. An increase in mass needs a corresponding increase in the total lift and, consequently, a greater lift and drag will result. Weight does not affect the the glide angle or the range that can be glided, but it does affect endurance since a higher speed, and consequently a higher FF, would be required to remain level.
Factors affecting glide angle:
Altitude?
The altitude at which a glide is undertaken does not affect the glide angle, however at a higher altitude the TAS must be increased, which means the best glide speed will increase as will the rate of descent.
Factors affecting glide angle:
Wind?
When gliding into the wind, less ground distance is covered (lower ground speed) for the height lost, than when gliding downwind(higher ground speed). Headwind the glide angle will be steeper, and shallow with a tailwind,
