Which part of the aeroplane has the largest effect on induced drag ? [ Certification weather ]

Question 220-1 : Wing tip engine cowling wing root junction landing gear

exemple 320 Wing tip. — .since there is a considerable pressure difference between lower and upper surfaces of a wing tip vortices are produced at the wingtips these tip vortices will then roll up and get around the local edges of a wing this phenomenon will have the largest effect on induced drag Wing tip.

Winglets ?

Question 220-2 : Decrease the induced drag decrease the static lateral stability increase the manoeuvrability create an elliptical lift distribution

exemple 324 Decrease the induced drag. — .since there is a considerable pressure difference between lower and upper surfaces of a wing tip vortices are produced at the wingtips these tip vortices will then roll up and get around the local edges of a wing this phenomenon will reduce the lift at the wingtip station so they can be represented as a reduction in effective wing span .experiments have shown that wings with square or sharp edges have the widest effective span .to compensate this loss three solutions are tip tank extra wing span and winglet winglets are small nearly vertical lifting surfaces mounted rearward and/or downward relative to the wing tips . /com en/com080 293a jpg. /com en/com080 293b jpg. winglets decrease the induced drag Decrease the induced drag.

Interference drag is the result of ?

Question 220-3 : Aerodynamic interaction between aeroplane parts e g wing/fuselage downwash behind the wing separation of the induced vortex the addition of induced and parasite drag

exemple 328 Aerodynamic interaction between aeroplane parts (e.g. wing/fuselage). — . /com en/com080 294 jpg.a wing root can cause interference drag Aerodynamic interaction between aeroplane parts (e.g. wing/fuselage).

Which line represents the total drag line of an aeroplane . err a 081 295 ?

Question 220-4 : Line c line a line b line d

exemple 332 Line c — .this is the drag to tas curve . /com en/com032 209 jpg. Line c

From an initial condition of level flight the flaps are retracted at a constant ?

Question 220-5 : Start to sink start to bank start to climb maintain level flight

exemple 336 Start to sink. — .lift = cl x 1/2 rho v² x s..cl = lift coefficient.rho = density.v = tas in m/s .s = surface.the question states at a constant pitch attitude it means 'at a constant angle of attack' so cl does not change .s surface will be decreased when flaps are retracted lift will reduce the aeroplane will subsequently start to sink .the question does not state 'fowler flaps' which modify surface and camber in this case flaps generally speaking increase the camber which increases clmax Start to sink.

From an initial condition of level flight the flaps are extended at a constant ?

Question 220-6 : Start to climb start to bank start to sink maintain level flight

exemple 340 Start to climb. — .if the flaps are extended with no change made to angle of attack the coefficient of lift will increase and the aircraft will gain altitude .flaps generally speaking increase the camber which increases clmax Start to climb.

Compared with the clean configuration the angle of attack at clmax with ?

Question 220-7 : Smaller larger unchanged smaller or larger depending on the degree of flap extension

exemple 344 Smaller. — .changing the configuration will change the properties of the airfoil and alter the lift and drag coefficients .with trailing edge flaps extended the lift coefficient will increase .then the angle of attack will be decreased at clmax . /com en/com080 298 jpg.clmax is reached at a lower angle of attack with trailing edge flaps extended Smaller.

The sensor of a stall warning system can be activated by a change in the ?

Question 220-8 : Stagnation point centre of lift transition region centre of gravity

exemple 348 Stagnation point. — .the stagnation point is the point at which the stream of air moving toward the wing divides into two streams one flowing above and the other flowing below the wing . /com en/com080 302a jpg. /com en/com080 302b jpg.in fluid dynamics a stagnation point is a point in a flow field where the local velocity of the fluid is zero Stagnation point.

The diagram shows the parameter x versus tas if a horizontal flight is ?

Question 220-9 : The induced drag the parasite drag the total drag the lift force

exemple 352 The induced drag. — .this diagram is already used for question n°1319 .'the diagram shows the parameter x versus tas if a horizontal flight is considered the axis x shows .the coefficient of lift' .here we can only choose 'the induced drag' . /com en/com032 209 jpg. The induced drag.

How are the speeds shown in the figure at point 1 and point 2 related to the ?

Question 220-10 : V1 = 0 and v2 > v v1 < v2 and v2 < v v1 = 0 and v2 = v v1 > v2 and v2 < v

exemple 356 V1 = 0 and v2 > v — V1 = 0 and v2 > v

An aerofoil with positive camber at a positive angle of attack will have the ?

Question 220-11 : On the upper side on the lower side in front of the stagnation point at the trailing edge

exemple 360 On the upper side. — .on the upper wing surface the airflow will have to travel a longer distance due to the camber than the airflow on the lower side in a same time period . /com en/com080 317 jpg. On the upper side.

The forces of lift and drag on an aerofoil are respectively normal and parallel ?

Question 220-12 : Relative wind/airflow chord line longitudinal axis horizon

exemple 364 Relative wind/airflow. — Relative wind/airflow.

Ground effect has the following influence on the landing distance ?

Question 220-13 : Increases decreases does not change increases only if the landing flaps are fully extended

exemple 368 Increases. — .as the airplane flies down from free air into ground effect the reduction of induced drag as it nears the runway comes into effect to make the airplane float past the point of intended touchdown .in the common case of an airplane coming in with excessive speed the usable portion of the runway may slip by with the airplane refusing to settle down to land a go around will probably be necessary on short fields approach as slowly as is consistent with safety Increases.

Assuming isa conditions and no compressibility effects if an aeroplane ?

Question 220-14 : Tas is higher at the higher altitude tas at both altitudes is the same ias is higher at the lower altitude tas is higher at the lower altitude

exemple 372 Tas is higher at the higher altitude. — .level flight at the same angle of attack means the same ias .lift formula = cl x 1/2 rho v² x s..cl = lift coefficient.rho = density.v = tas in m/s .s = surface..lift at altitude 1 = lift at altitude 2.they say same angle of attack thus cl is the same surface does not change and there is no compressibility effects .since 'rho' decreases with altitude tas must increase in order to keep 'rho x v²' unchanged Tas is higher at the higher altitude.

The lift to drag ratio determines the ?

Question 220-15 : Horizontal glide distance from a given altitude at zero wind and zero thrust maximum rate of climb endurance speed horizontal distance in the climb up to a given altitude

exemple 376 Horizontal glide distance from a given altitude at zero wind and zero thrust. — Horizontal glide distance from a given altitude at zero wind and zero thrust.

Which type of flap is shown in the picture . err a 081 330 ?

Question 220-16 : Fowler flap split flap plain flap double slotted flap

exemple 380 Fowler flap. — . /com en/com080 182 jpg. fowler flap slides backwards before hinging downwards thereby increasing both camber and chord creating a larger wing surface better tuned for lower speeds it also provides some slot effect Fowler flap.

Which type of flap is shown in the picture . err a 081 331 ?

Question 220-17 : Split flap plain flap single slotted flap fowler flap

exemple 384 Split flap. — . /com en/com080 182 jpg. Split flap.

The application of the area rule on aeroplane design will decrease the ?

Question 220-18 : Wave drag skin friction drag induced drag form drag

exemple 388 Wave drag. — .the area rule is an important concept related to the drag on an aircraft or other body in transonic and supersonic flight the area rule came into being in the early 1950s when production fighter designs began pushing ever closer to the sound barrier designers had found that the drag on these aircraft increased substantially when the planes traveled near mach 1 a phenomenon known as the transonic drag rise illustrated below . increase in wave drag at transonic mach numbers . /com en/com080 334b jpg.this increase in drag is due to the formation of shock waves over portions of the vehicle which typically begins around mach 0 8 and this drag increase reaches a maximum near mach 1 because of its source this type of drag is referred to as wave drag Wave drag.

At a constant angle of attack which of the following factors will lead to an ?

Question 220-19 : Tailwind headwind increase of aeroplane mass decrease of aeroplane mass

The wing of an aeroplane will never stall at low subsonic speeds as long as ?

Question 220-20 : The angle of attack is smaller than the value at which the stall occurs the ias exceeds the power on stall speed the cas exceeds the power on stall speed there is a nose down attitude

exemple 396 The angle of attack is smaller than the value at which the stall occurs. — The angle of attack is smaller than the value at which the stall occurs.

The induced drag coefficient cdi is proportional with ?

Question 220-21 : Cl² cl square root cl clmax

exemple 400 Cl². — .the coefficient of induced drag cdi = cl² / pi x ar .cl is lift coefficient.pi is 3 14159.ar is aspect ratio.cdi is proportional with cl² Cl².

The stall speed increases when all other factors of importance being constant ?

Question 220-22 : Pulling out of a dive weight decreases minor altitude changes occur e g 0 10000 ft spoilers are retracted

exemple 404 Pulling out of a dive. — .pulling out of a dive . /com en/com080 359 jpg.an aircraft is in a dive with an airspeed of 100 knots when the pilot pulls back sharply on the elevator control gravity and centrifugal force prevent an immediate alteration of the flightpath but the aircraft's aoa changes abruptly from quite low to very high since the flightpath of the aircraft in relation to the oncoming air determines the direction of the relative wind the aoa is suddenly increased and the aircraft would reach the stalling angle at a speed much greater than the normal stall speed Pulling out of a dive.

The angle of attack of a wing profile is defined as the angle between ?

Question 220-23 : The undisturbed airflow and the chordline the local airflow and the mean camberline the local airflow and the chordline the undisturbed airflow and the mean camberline

exemple 408 The undisturbed airflow and the chordline. — The undisturbed airflow and the chordline.

In which phase of the take off is the aerodynamic effect of ice located on the ?

Question 220-24 : The last part of the rotation the take off run during climb with all engines operating all phases of the take off are equally critical

exemple 412 The last part of the rotation. — Lift starts during rotation ice located on the wing leading edge will affect the airflow and thus will dramatically degrade the lift . /com en/com080 382 jpg.you are at high speed and after v1 it is too late to stop the aircraft since the remaining runway distance is too short The last part of the rotation.

Which statement is correct at the speed for minimum drag subsonic ?

Question 220-25 : The gliding angle is minimum assume zero thrust propeller aeroplanes fly at that speed at maximum endurance the cl/cd ratio is minimum assume zero thrust induced drag is greater than the parasite drag

exemple 416 The gliding angle is minimum (assume zero thrust). — .minimum glide angle occurs at the speed for minimum drag if you want to travel the maximum distance possible with zero thrust you need to fly at the speed that wich gives maximum lift to drag ratio vmd velocity for minimum drag The gliding angle is minimum (assume zero thrust).

The induced angle of attack is the result of ?

Question 220-26 : Downwash due to tip vortices a large local angle of attack in a two dimensional flow downwash due to flow separation change in direction of flow due to the effective angle of attack

exemple 420 Downwash due to tip vortices. — .induced angle of attack is a slight decrease in the effective angle of attack of a wing due to the diversion of the air stream by the wings as the wings produce the downwash that ultimately engenders lift to support the aircraft the downwards twist of the air stream shallows the effective angle of attack slightly Downwash due to tip vortices.

The following factors increase stall speed ?

Question 220-27 : An increase in load factor a forward cg shift decrease in thrust a higher weight selecting a higher flap setting a forward cg shift increasing bank angle increasing thrust slat extension a lower weight decreasing bank angle a smaller flapsetting

exemple 424 An increase in load factor, a forward cg shift, decrease in thrust. — .stall speed increases with the square root of the load factor .with a forward cg shift you have to increase downward force on the tail to maintain equilibrum thus stall speed increases .the thrust line is pointing upwards and making a small contribution to lift a decrease in thrust will increase stall speed An increase in load factor, a forward cg shift, decrease in thrust.

The stall speed ias will change according to the following factors ?

Question 220-28 : May increase with altitude especially high altitude will increase during icing conditions and will increase when the c g moves forward may increase when the c g moves forward with higher altitude and due to the slip stream from a propellor on an engine located forward of the wing will increase in a turn higher temperature and will increase when the c g moves aft will increase with increased load factor more flaps and increased bank angle in a turn

exemple 428 May increase with altitude, especially high altitude, will increase during icing conditions and will increase when the c.g. moves forward. — A stall occurs when the smooth airflow over the airplane's wing is disrupted and the lift degenerates rapidly this is caused when the wing exceeds its critical angle of attack this can occur at any airspeed in any attitude with any power setting .. altitude .the ias stall speed is considered constant at low altitudes because of the tas stall speed increases due to the decreasing altitude but the ias is almost constant this is because the factor increasing the tas stall speed density also affects the ias speed in the same amount .however at higuer altitudes we consider another factor the compresibility that affects the anemometer and hence increases the reading of ias .resuming the ias stall speed is considered constant at lower altitudes below 10000 ft and increases with altitude at higuer altitudes due to compresibility effects .. wing contamination .wings covered with rime ice hoar frost and remains of bugs and dirt will cause an early separation of the boundary layer and the stall speed will increase sometimes even by 4% remember that the same applies to the propeller but then a decrease in thrust will be the result .. forward cg .the airplane will stall at a higher speed with a forward cg location this is because the stalling angle of attack is reached at a higher speed due to increased wing loading May increase with altitude, especially high altitude, will increase during icing conditions and will increase when the c.g. moves forward.

The stalling speed in ias will change according to the following factors ?

Question 220-29 : Increase during turn increased mass and forward c g location increase with increased load factor more flaps but will not increase due to the bank angle in a turn increase with increased load factor icing conditions and an aft c g location decrease in a forward c g location higher altitude and due to the slip stream from a propeller on an engine located forward of the wing

exemple 432 Increase during turn, increased mass and forward c.g. location. — .one quick note . an airplane always stalls at the same critical angle of attack. an airplane can stall at any airspeed .thus the stall can always reach the critical angle of attack at any airspeed .a forward cg = higher stall speed.an aft cg = lower stall speed.turning there is a bit of 'loss' in the vertical component of lift because some of the lift was diverted to cause the plane to bank for example an aircraft in a 30° bank increases it's stall speed by 7% .an increase in mass = higher stall speed.increased mass has the same outcome as increased g so far as the wing looks at weight .we need more lift due to increased mass we have to either increase the speed v or the angle of attack cl in the lift formula lift = 1/2 rho x v² x wing area x cl Increase during turn, increased mass and forward c.g. location.

The stalling speed in ias will change according to the following factors ?

Question 220-30 : May increase during turbulence and will always increase when banking in a turn will decrease with a forward c g location lower altitude and due to the slip stream from a propeller on an engine located forward of the wing will increase with increased load factor icing conditions and more flaps will increase during turn increased mass and an aft c g location

exemple 436 May increase during turbulence and will always increase when banking in a turn. — .the stalling speed may increase during turbulence .altitude bank and pitch will change during turbulence therefore stall speed may increase with increased load factor .the stalling speed will always increase when banking in a turn .stall speed increases with the square root of the load factor and the load factor in a turn is 1/cos bank angle May increase during turbulence and will always increase when banking in a turn.

On a symmetrical aerofoil the pitching moment for which cl=0 is ?

Question 220-31 : Zero undetermined positive pitch up negative pitch down

'a line connecting the leading and trailing edge midway between the upper and ?

Question 220-32 : The camber line the chord line the mean aerodynamic chord line the upper camber line

exemple 444 The camber line. — The camber line.

What is the stagnation point ?

Question 220-33 : The point where the velocity of the relative airflow is reduced to zero the intersection of the total aerodynamic force and the chord line the intersection of the thrust vector and the chord line the point relative to which the sumtotal of all moments is independent of angle of attack

exemple 448 The point where the velocity of the relative airflow is reduced to zero. — The point where the velocity of the relative airflow is reduced to zero.

What is the effect on induced drag of mass and speed changes all other factors ?

Question 220-34 : Decreases with increasing speed and decreasing mass decreases with decreasing speed and decreasing mass increases with increasing speed and decreasing mass increases with increasing speed and increasing mass

exemple 452 Decreases with increasing speed and decreasing mass. — .we know that induced drag is proportional to the angle of attack so .if you reduce speed you must increase your angle of attack to maintain the same lift assuming we want to stay in level flight if we increase speed you must decrease your angle of attack thus induced drag will decrease .it's basicaly the same for the mass .at a given speed and altitude to maintain level flight with a lighter aircraft less angle of attack is required thus induced drag will decrease Decreases with increasing speed and decreasing mass.

What increases the critical angle of attack use of ?

Question 220-35 : Slats flaps spoilers fuselage mounted speed brakes

When considering a swept back wing with no corrective design features at the ?

Question 220-36 : Tip stall will occur first which produces a nose up pitching moment wing root stall will occur first which produces a rolling moment tip stall will occur first which produces a nose down pitching moment leading edge stall will occur first which produces a nose down pitching moment

exemple 460 Tip stall will occur first, which produces a nose-up pitching moment. — Tip stall will occur first, which produces a nose-up pitching moment.

Which boundary layer when considering its velocity profile perpendicular to the ?

Question 220-37 : Turbulent boundary layer laminar boundary layer no difference the boundary layer in the transition between turbulent and laminar

exemple 464 Turbulent boundary layer. — .the boundary layer extends from the surface to near freestream speed think of the surface layer as molecules bouncing slowly along in the turbulent layer they are ripped smartly up to high speed very soon after you leave the surface and then slowly speed up toward freestream over the rest of the layer Turbulent boundary layer.

The si unit of measurement for pressure is ?

Question 220-38 : N/m² kg/m³ lb/gal bar/dm²

.icao annex 5 units of measurement attachment b . 2 mass force and weight .2 1 the principal departure of si from the gravimetric system of metric engineering units is the use of explicitly distinct units from mass and force in si the name kilogram is restricted to the unit of mass and the kilogram force from which the suffix force was in practice often erroneously dropped is not to be used in its place the si unit of force the newton is used likewise the newton rather than the kilogram force is used to form derived units which include force for example pressure or stress n/m² = pa energy nm = j and power nm/s = w

The polar curve of an aerofoil section is a graphic relationship between ?

Question 220-39 : Lift coefficient cl and drag coefficient cd tas and stall speed angle of attack and lift coefficient cl drag coefficient cd and angle of attack

exemple 472 Lift coefficient cl and drag coefficient cd. — Lift coefficient cl and drag coefficient cd.

The speed for minimum glide angle occurs at an angle of attack that corresponds ?

Question 220-40 : Cl/cd max clmax cl/cd² max cl³/cd² max

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