Progress 2 Flashcards
An aerofoil travelling at supersonic speed will?
a. have its centre of pressure at 50 % chord.
b. have its centre of pressure at 25% chord
a. have its centre of pressure at 50 % chord.
At M 0.8 a wing has supersonic flow between 20% chord and 60% chord. There will be a shockwave? a. at 20% chord only. b. at 20% chord and 60% chord. c. at 60% chord only
c. at 60% chord only
High speed buffet is caused by?
b. the high speed airflow striking the leading edge of the wing.
d. the airflow being detached by the shock wave and the turbulent flow striking the tail
d. the airflow being detached by the shock wave and the turbulent flow striking the tail
The term ‘transonic speed’ for an aircraft means?
b. speeds where the airflow is completely supersonic
c. speeds where the airflow is partly subsonic and partly supersonic
c. speeds where the airflow is partly subsonic and partly supersonic
The “area rule” applied to high speed aircraft requires?
b. that the variation of cross sectional area along the length of the aircraft follows a smooth pattern
c. that the maximum cross sectional area of the fuselage should occur at the wing root
b. that the variation of cross sectional area along the length of the aircraft follows a smooth pattern
Mach Trim is a device which?
a. moves the centre of gravity to maintain stable lateral stick forces in the transonic region
b. automatically compensates for pitch changes while flying in the transonic speed region
b. automatically compensates for pitch changes while flying in the transonic speed region
What is the result of a shock‑induced separation of airflow occurring symmetrically near the wing root of a sweptwing aircraft?
a. a severe nose-down pitching moment or “tuck under”
b. a high‑speed stall and sudden pitch up
a. a severe nose-down pitching moment or “tuck under”
For a multi-engined aircraft, V
MCG is defined as the minimum control speed on the ground with one engine inoperative. The aircraft must be able to?
b. continue the take off or abandon it
c. continue the take off using primary controls only.
c. continue the take off using primary controls only.
To give the best obstacle clearance on take off, take off should be made with?
b. flaps partially extended and at best angle of climb speed (Vx).
d. flaps retracted and at best angle of climb speed (Vx).
d. flaps retracted and at best angle of climb speed (Vx).
If an aircraft with a gross weight of 2,000 kg were subjected to a total load of 6,000 kg in flight,
the load factor would be? _ G’s.
3G
What criteria determines which engine is the “critical” engine of a twin‑engine aeroplane?
a. the one with the centre of thrust farthest from the centerline of the fuselage
b. the one with the centre of thrust closest to the centerline of the fuselage
b. the one with the centre of thrust closest to the centerline of the fuselage
The horizontal stabilizer usually provides a download in level flight because?
a. the main plane lift is always positive
b. the lift/weight and thrust/drag couples combine to give a nose down pitch
b. the lift/weight and thrust/drag couples combine to give a nose down pitch
If the ailerons are deflected to 10°, compared to 5°, this will cause?
a) increased rate of roll
b) increased angle of bank
a) increased rate of roll
Ailerons may be rigged slightly down (drooped)?
c. to allow for up-float in flight to bring the aileron into the streamlined position
d. to give a higher CL max for take-off
c. to allow for up-float in flight to bring the aileron into the streamlined position
er spring tab að létta á?
já, against high air loads.
Purpose of anti-balance tabs?
give more feel to the controls
Following re-trimming for straight and level flight because of forward CG movement?
a. nose up pitch authority will be reduced
b. nose down pitch authority will be reduced
a. nose up pitch authority will be reduced
A high wing configuration with no dihedral, compared to a low wing configuration with no dihedral, will provide?
a. greater longitudinal stability
d. greater lateral stability due to the airflow pattern around the fuselage when the aircraft
d. greater lateral stability due to the airflow pattern around the fuselage when the aircraft
það virðist vanta í endann á þessu en þetta var rétt svar.
Dihedral angle is?
b. the angle measured between the main plane and the normal axis
d. the upward and outward inclination of the main planes to the horizontal datum
d. the upward and outward inclination of the main planes to the horizontal datum
If an aircraft is loaded such that the stick force required to change the speed is zero?
a. the CG is on the neutral point
b. the CG is behind the neutral point
c. the CG is on the manouevre point
a. the CG is on the neutral point
Gyroscopic precession: results in any yawing around the ___ axis results in a pitching moment
normal
When a force is applied at a point on the rim of a spinning disc, the resultant force acts in which direction and at what point? In the __ direction as the applied force, 90° __ in the plane of rotation
same, ahead
Angle of attack: depends on ____ speed and engine ___ speed
forward, rotational
A propeller rotating clockwise as seen from the rear, creates a spiralling slipstream that tends to rotate the aeroplane to the left around the normal axis, and to the __ around the ___ axis
right, longitudinal
Asymmetric blade effect veldur yaws to the ___ when at ___ angles of attack
left, high
Blade angle: Angle between ___ and _____
chord line, plane of rotation
The distance a propeller actually advances in one revolution is? ____ pitch
Effective
Propeller efficiency: ratio of ___ horsepower to horsepower
thrust, shaft
On a non-swept wing, when the aerofoil is accelerated from subsonic to supersonic speeds, the aerodynamic centre shifts from __% to about __% of the aerofoil chord.
25, 50
Aerodynamic Center is a stationary point only when the airflow is ___.
subsonic
For a wing section of given thickness, the critical Mach number? will ____ if angle of attack is increased.
decrease
As air flows through shockwave: static pressure ___, density ___, temperature ___.
increases, increases, increases
The influence of weight (wing loading) on the formation of shockwaves is? low wing loading will give a ___ M CRIT
higher
At what speed does an oblique shock wave move over the earth surface? ___ ___ speed
Aircraft ground
Wave drag: the conversion of ___ energy into ___ energy by the shock wave
mechanical, thermal
Normal shock wave; air behind is always __sonic and in the same direction as the original airflow.
sub
The “area rule” applied to high speed aircraft requires that the variation of __ ___ area along the length of the aircraft follows a ___ pattern
cross sectional, smooth
What is the purpose of fitting the engines to an aircraft using wing mounted pylons? The wing structure can be __ because the engine acts as a mass balance and also relieves __ __ ___.
lighter, wing bending stress
If an aircraft weight is reduced by 15%, Va will? increase/decrease by __%
decrease by 7.5%
If an aircraft is flown at its design manoeuvring speed VA it [is/is not] possible to exceed the limit load.
not possible
Hvernig er “maximum structural cruising speed” skrifað?
Vno
During a glide, the forces acting on the aeroplane are..
lift, drag and weight. (No thrust).
As bank angle is increased in a turn at a constant IAS, the load factor will?
increase at an increasing rate.
