Progress 1 Flashcards
When the angle of attack of a symmetrical aerofoil is increased, the centre of pressure will?
Select one:
c. Remain unaffected
d. Move toward the leading edge
c. Remain unaffected
Rétt eða rangt? The thickness/chord ratio is expressed as a percentage of the chord
Rétt
Rétt eða rangt? It is easier for air to flow over a well rounded leading edge radius than a sharp leading edge.
Rétt
A stall warning device must be set to operate at a speed about _% above the stalling speed
5-10%
A typical stalling angle of attack for a wing without sweepback is? _°.
16
A wing of constant thickness which is not swept back?
d. will stall evenly across the span
e. could drop a wing at the stall due to the lack of any particular stall inducing characteristics
e. could drop a wing at the stall due to the lack of any particular stall inducing characteristics
Þú hefur þyngdina 100 og átt að finna stall hraða m.v. þyngdina 220 (stall hraði nú er 50). Hvernig reiknar þú þetta?
Gamli stall hraði * sqrt(nýja þyngd/gamla þyngd)
If the aircraft weight is increased without change of C of G position, the stalling angle of attack will?
remain the same
In a developed spin?
a. the angle of attack of both wings will be positive
b. the angle of attack of both wings will be negative
c. the angle of attack of one wing will be positive and the other will be negative
d. the down going wing will be stalled and the up going wing will not be stalled
a. the angle of attack of both wings will be positive
Slots increase the stalling angle of attack by?
a. Increasing leading edge camber
b. delaying separation
b. delaying separation
The input data to a stall warning device (e.g. stick shaker) system is?
a. angle of attack only.
b. angle of attack, and in some systems rate of change of angle of attack
b. angle of attack, and in some systems rate of change of angle of attack
To recover from a spin, the elevators should be?
b. moved down to reduce the angle of attack
c. set to neutral
b. moved down to reduce the angle of attack
Vortex generators are used:
b. to reduce boundary layer separation
c. to induce a root stall
b. to reduce boundary layer separation
An aircraft has a L/D ratio of 15:1 at 50 kts in calm air. What would the L/D ratio be with a direct headwind of 25 kts?
15:1
Hvaða drag eykst ef þú minnkar flughraða? (EAK)
induced drag
Aspect ratio of a wing is defined as the ratio of the? __ to the ___
wingspan, mean chord
At a given True Air Speed, what effect will increased air density have on the lift and drag of an aircraft?
Lift increases, drag also increases.
In theory, if the airspeed of an airplane is doubled while in level flight, parasite drag will become?
four time greater
On a wing, the force of lift acts perpendicular to, and the force of drag acts parallel to the?
a. flightpath.
b. longitudinal axis.
c. chord line.
d. longitudinal datum
a. flightpath.
That portion of the aircraft’s total drag created by the production of lift is called?
a. induced drag, and is greatly affected by changes in airspeed
b. induced drag, and is not affected by changes in airspeed
a. induced drag, and is greatly affected by changes in airspeed
The best L/D ratio of an aircraft occurs when parasite drag is equal to ___.
induced drag
The resistance, or skin friction, due to the viscosity of the air as it passes along the surface of a wing is a type of? a. induced drag. b. form drag. c. parasite drag d. interference drag.
c. parasite drag
When gross weight is increased, induced drag increases more/less than parasite drag.
induced drag increases more
Which relationship is correct when comparing drag and airspeed?
a. Parasite drag varies inversely as the square of the airspeed
b. Induced drag increases as the square of the airspeed.
c. Parasite drag increases as the square of the lift coefficient divided by the aspect ratio
d. Induced drag varies inversely as the square of the airspeed.
d. Induced drag varies inversely as the square of the airspeed.
The SI unit of force is the ___.
Newton
Newton´s third law of motion states?
Every action has an equal and opposite reaction
An aircraft’s critical mach number is:
a. The speed of the airflow when the aircraft first becomes supersonic
b. The speed of the aircraft when the airflow somewhere reaches the speed of sound
c. The indicated airspeed when the aircraft first becomes supersonic
d. The aircraft´s Mach number when airflow over it first reaches the local speed of sound
d. The aircraft´s Mach number when airflow over it first reaches the local speed of sound
Dynamic pressure is equal to?
a. density times speed squared
b. Half the density times the indicated airspeed squared
c. Half the true airspeed times the density squared
d. Half the density times the true airspeed squared
d. Half the density times the true airspeed squared
Dynamic Pressure is?
a. The total pressure at a point where a moving airflow is brought completely to rest
b. The amount by which the pressure rises at a point where a moving airflow is brought completely to rest
c. The pressure due to the mass of air pressing down on the air beneath
d. The pressure change caused by heating when a moving airflow is brought completely to rest
b. The amount by which the pressure rises at a point where a moving airflow is brought completely to rest
The inputs to an Airspeed indicator are from?
a. A static source
b. Pitot pressure
c. A pitot and a static source
c. A pitot and a static source
True or false? The viscosity of air is very high
false
If the pressure on one side of a surface is lower than on the other side?
a. A force per unit area will exist, acting in the direction of the lower pressure.
c. A force will be generated, acting in the direction of the higher pressure.
a. A force per unit area will exist, acting in the direction of the lower pressure.
If the velocity of an air mass is increased? The kinetic energy will ___, the dynamic pressure will ___ and the static pressure will ___.
increase, increase, decrease
In accordance with the principle of continuity? Changes in cross-sectional area of a streamline flow will affect the air ____.
velocity
The statement, pressure plus Kinetic Energy is constant, refers to what theory?
Bernoulli
The statement, “Energy and mass can neither be created nor destroyed, only changed from one form to another” refers to what theory?
The principle of continuity
If the aircraft weight is increased without change of C of G position, the stalling angle of attack
will?
Remain the same
On an untapered wing without twist the downwash?
a. increases from root to tip
b. increases from tip to root
a. increases from root to tip
To recover from a spin, the elevators should be?
a. moved up to increase the angle of attack
b. moved down to reduce the angle of attack
c. set to neutral
d. allowed to float
b. moved down to reduce the angle of attack
At a given True Air Speed, what effect will increased air density have on the lift and drag of an aircraft?
Both increase
In theory, if the airspeed of an airplane is doubled while in level flight, parasite drag will become?
4x as great
That portion of the aircraft’s total drag created by the production of lift is called ___ drag, and is/is not affected by changes in airspeed
induced, is affected
“Changes in cross-sectional area of a streamline flow will affect the air velocity.” This is according to the principle of ___.
continuity.
“Pressure plus Kinetic Energy is constant”. Hvaða lögmál er þetta?
Bernoulli
Hvaða lögmál er þetta? “Every action has an equal and opposite reaction”
Þriðja lögmál Newton
Hvaða lögmál er þetta? “The acceleration of a body from state of rest, or uniform motion in a straight line, is proportional to applied force and inversely proportional to the mass”
Annað lögmál Newton
Hvaða lögmál er þetta? “A body will remain at rest or in uniform motion in a straight line unless acted on by an external force”
Fyrsta lögmál Newton
Hver er mælieining Mass?
Kg
Hver er mælieining Force?
N
Hvað færð þú ef þú deilir EAS með relative density?
TAS
“A * V * p = Constant”. Hvaða lögmál er þetta?
Principle of continuity
Hvaða horn er á milli longitudinal ás vélar og chordline?
Angle of incidence
Hvað er þetta? “Air close to, but unaffected of the presence of aircraft”
Relative airflow
CP moves ___ when AoA increases on Cambered airfoils
forward
Hver er formúla lift?
L = 1/2 hró * V^2 * Cl * S
Ef þú ímyndar þér vænt og þarna er AoA m.v. relative airflow og effective airflow, hvað heita viðkomandi angles of attack fyrir hvort um sig?
Relative airflow: Induced angle of attack
Effective airflow: Effective angle of attack
Hvað gerist fyrir effective angle of attack ef þú hallar vænt aftur (togar í stýri)?
það minnkar, held að induced angle of attack stækki.
Entering Ground effect: The decreased downwash will give an ___ in the effective angle of attack
increase
Wing tip vortices __ drag, ___ lift
increase, decrease
Total drag skiptist í hvaða tvo flokka?
Induced drag og parasite drag
Hvað er annað nafn yfir Skin friction drag og Form drag?
Profile drag
Hvað er annað nafn yfir Skin friction drag og Form drag?
Profile drag
Icing conditions may be encountered in the atmosphere when?
a. The pilot can visually identify build-up on the wings, tailplane or flight controls by looking through the flight deck windows; at night by using the ice detection lights.
c. Visual evidence of the accumulation of airframe icing may not exist
c. Visual evidence of the accumulation of airframe icing may not exist
If it is suspected that ice may have formed on the tailplane and longitudinal control difficulties are experienced following flap selection, the prudent action to take would be?
a. immediately decrease the flap setting
b. allow the speed to increase
c. select a greater flap deflection because this will increase CL max
d. reduce the angle of attack
a. immediately decrease the flap setting
The ___ layer is the region where the speed of the air decreases more and more until it has its lowest value of zero on the body surface
boundary
if IAS is halved, the Parasite Drag will be ____.
one quarter of its previous value.
The higher the CL (the lower the IAS), the weaker/stronger the wing tip vortices.
stronger
Wing tip vortices weaken/strengthen downwash.
strengthen
Strengthened downwash inclines wing lift forwards/rearwards.
rearwards
The greater the rearward inclination of wing lift, the greater/weaker the induced drag.
greater
Er heavy rain að hafa áhrif á stall hraða?
já
Does load factor affect stall angle?
No
Í spinning þá eru vængir vélar above/below stalling angle?
báðir above stalling angle. One wing stalls more than the other.
Main purpose of having HLD is..
To reduce take-off and landing distance
Leading edge flaps increases/decreases the stalling
angle
increases
