Lernkartei POF T2 (Seite 7 von 9)

Karten	336
Sprache	Deutsch
Kategorie	Physik
Stufe	Andere
Erstellt / Aktualisiert	16.05.2015 / 22.07.2020
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Static directional stability is mainly provided by:

the fin

wing dihedral

Which design features improve static lateral stability? 1) Anhedral 2) Dihedral 3) Forward sweep 4) Sweepback

2 and 4

The effect of a high wing with zero dihedral is as follows:

positive dihedral effect.

negative dihedral effect

no effect

What happens to lateral stability when flaps are extended?

Lateral stability is decreased.

Lateral stability is unaffected, as the wings are symmetrical.

Lateral stability is increased as lift is increased.

Which of the following provides a positive contribution to static directional stability?

a dorsal fin

A low wing as compared with a high wing.

Moving the centre of gravity aft.

The effect of a swept wing is to give:

positive dihedral effect.

decreased roll-with-yaw effect.

adverse yaw effect.

Which wing design feature decreases the static lateral stability of an aeroplane?

Anhedral wing

Increased wing span.

Dihedral

Which of the following gives an unstable contribution in side-slip?

Flap extension.

High wing

Wing sweep.

A pitch up could be caused by:

forward movement of the centre of pressure.

forward movement of the centre of gravity.

The fin of an aircraft is a symmetrical aerofoil:

It could stall if the fin angle of attack is too great.

It can give no lift, only drag.

It will only provide an aerodynamic force when the rudder is moved.

If the sum of moments in flight is not zero, the aeroplane will rotate about:

C.G.

If the elevator trim tab is deflected up, the cockpit trim indicator shows: nose

nose down

A symmetrical fin will give a side force:

when the rudder is applied and when the aircraft yaws.

only when the aircraft yaws.

with rudder neutral and no yaw.

only when rudder is applied.

While an aircraft is rolling, the down-going and up-going wing:

provide a damping force which reduces the rate of roll.

will stall due to the increased effective angle of attack.

provide a force to increase the rate of roll.

Aeroplane manoeuvrability decreases for a given control surface deflection when:

IAS decreases.

IAS increases.

flaps are retracted at constant IAS.

When ice is present on the stabilizer, deflection of flaps may cause:

the stabilizer to stall and a vertical dive.

the stabilizer to stall and a pitch up situation.

both wings and stabilizer to stall.

roll movement due to directional instability.

When the rudder is moved to the right, the force acting on the fin:

gives a rolling moment to the right.

gives a rolling moment to the left.

gives a yawing moment but no rolling moment.

Balance tabs:

move in the opposite direction to control surfaces and the same direction as trim tabs.

move in the opposite direction to both control surfaces and trim tabs.

move in the same direction as the control surface.

move in the same direction as control surfaces and trim tabs.

Which aerodynamic desing features can be used to reduce control forces?

Horn balance, balance tab, servo tab.

Mass balance, horn balance, artificial feel system.

An aeroplane's sideslip angle is defined as the angle between the:

speed vector and the plane of symmetry.

speed vector and the horizontal plane.

speed vector and normal axis.

ateral axis and the horizontal plane.

If a turbulent gust causes an aeroplane to roll:

the down-going wing experiences an increase in angle of attack.

the down-going wing experiences a decrease in angle of attack.

the down-going wing has no angle of attack.

In a twin-engined jet powered aeroplane (engines mounted below the low wings) the thrust is suddenly increased. Which elevator deflection will be required to maintain the pitching moment zero?

Down.

Up.

No elevator movement will be required because the thrust line of the engines remain unchanged.

Load factor is increased by:

Upward gusts.

An increase in aeroplane mass.

Which of the following is a correct statement of gust factorss applied in certification under JAR-25?

25 Ft/sec at VB

50 Ft/sec at VC

55 ft/sec at VD

66 ft/sec at VD

The shape of the gust load diagram is also determined by the following three vertical speeds in ft/s (clean configuration):

25, 50, 66

35, 55, 66

Stick force gradient? normal flight? max. ?

normal flight load factor is 1 ==> max. 2,5

if the airspeed increases and decreases during longitudinal phugoid oscillations, teh aircraft:

can be easily controlled by the pilot

is constantly changing AoA making it difficult to reduce the magnitude of the oscillations

Which part of an aeroplane provides the gratest psoitive contribution to sttaic longitudinal stability?

the horizontal plane

the wing

teh engine

the fuselage

What is the problem, when the stick force per G becomes too low?

there is a danger of over-stressing the aircraft inadvertently => if the aircraft has higher limit load factor, this danger obviously reduces. Among all the limitations on aircraft, the stick force per G is not one

A pitch up could be caused by?

forward movement of the CP

forward movement of the CG

What is the position of the CG in relation to the neutral pointwhen the CG is on teh aft limit?

In front of the neutral point

Just behind the neutral point

A negative contribution to the static longitudinal stability of conventional jet transport aeroplanes is provided by:

the fuselage

a fixed elevator deflection

a fixed trim position

the tail

Which statement concerning longitudinal stability and control is correct?

a bob weight reduces the stick force per g

A bob weight and a down spring have the same effect on the stick force stability

a bobweight and a down spring

Bobweight: fittet into a flight system to improve the stick force stability => acts in teh same way as the downspring

==> by acceleration it will provide an increment of stick force

down-spring: similar device

When an aeroplane has zero static longitudnal stability, the pitching moment coefficient Cm versus AoA line:

is horizontal

has a positive slope

is vertical

has a negative slope

The distance between the CG Datum and the CG neutral point in straight and level flight is called the:

CG static margin

CG manoeuvre margin

Different Short and long oscillatiion

short Oscillation: Should always be heavily damped; altitude and speed remains constant

Long Oscillation = Phugoid: Should always be little damped; altitude and speed varies significantly

positive stick psoition stability means that:

a) you have to pull your stick back if teh speed decreases

b) you have to push your stick forward if the speed increases

The CG of an aeroplane is in a fixed position forward of the neutral point. Speed changes cause a departure from the trimmed position.

An increase of 10 its from the trimmed position at high speed has less effect on the stick force than an increase of 10 its from the trimmed position at low speed

maintaining a steady speed below the trimmed speed requires a push force

how does positive camber of an aerofoil affect sttaic longitudinal stability?

no effect, because camber of the aerofoil produces a constant pitch down moment coefficient, independent of AoA

negatively, because the lift vector rotates forward at increasing AoA

POF T2

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