POF T2
pof
pof
Typically teh CL/CD ratio is:
regarding deep staal characteristics, identify whetever the following statements are correct or incorrect?
1) An aeroplane with a low horizontal tail and wings with sweepback is normally prone to deep staal
2) an aeroplane with a canard is normally prone to deep stall
1 and 2 incorrect
Canard winf => feature?
if approaching a stall condition, the canards small before the main wing do => pitch down moment
teh stalling angle of an aerofoil is approximately
16 degrees
the min. speed at which lift equals weight is calles
VS1g
When looking at the airflow over the wing, from the wing surface and up, the air is:
With increasing AoA the CP will reach its most forward point :
Which aeroplane design has the highest probability of a super stall?
the purpose pf a fixed spoiler on the leading edge of a wing at the root is to:
The load factor is less than 1
1) stall speeds are determined with the CG at the forward limit
2) Min. control speeds are determined with the CG at the aft limit
1 and 2 correct
A fixed staal strip on the leading edge of teh wing at the root will:
Accelerated STall:
deep staal:
Accelerated STall: the staal that occurs while teh aircraft is experincing a load factor higher than 1 g ==> staals at higher speed
deep staal: dangerous => that affects certain aircraft designs, notably those with a T-tail conf. the turbulent wake of a stalled main wing blankets the horizontal stabilizer, rendering the elevators ineffective and preventing the aircraft from recovering from the staal => AoA between 40-60 degrees
fixed spoiler ?
a stall strip on the leading edge => the sharp leading edge of the stall strip ensures a lower stalling angle than the rounded leading edge of the wing and thus inducing stall
Staal speed increased => Formel mit Gewicht
V s new = vs old x Wurzel( new weight/ old weight)
WIe verhält sich die stalling speed mit der Höhe ?
constant at low altitudes as long as the speed is low enough for compressibility effects not to be present ==> stall speed Increased with altitude increasing
Wing forces => what theay do?
prevents the outward draft of the boundary layer and thus reduces the tendency to tip stall => higher AoA
what makes the tailplane?
normally produces a downwards force => when the tailplane stalls, the downward force will be gone immediately and the aeroplane pitches down
Difference straight and swept wing on stalling speed? Anhedral and T-Tail?
Anhedral and T-Tail no influence on stalling speed => wing sweep causes the Cl curve less slope and a smaller value of CL max than straight wings => the higher sweep, the lower the value of CL MAX = a higher stall speed
What is a spin?
a spin is a controlled or uncontrolled manouevre, = stalled situation (both wings are stalled) with the nose usually pointed sharply downwards in which the aircraft descends in a helical path with an AoA greater than the Angle of max. lift => Occurs with teh wings in a stalled flight condition plus a yaw and roll n the same direction and that it can develop in any attitude, at any airspeed at/or below manoeivering speed
Clim propeller ? Cruise propeller?
Clim propeller = low pitch Cruise propeller = high pitch
When the lift coefficient of a negatively cambered aerofoil section is zero, the pitching moment is:
How can the propeller thrust be increased ?
increase in diameter, RPM or number of blades => but also by moving the power lever forward
24537 An aircraft flying at 150kts EAS at 10000ft compared to the same aircraft flying at the same EAS at sea level will have:
Which propleller design characteristics reduce the noise level?
low blade tip speed by low RPM or low diameter
The point, where the aerodynamic lift acts on a wing is:
centre of pressure
A constant speed propeller is one which:
rotates at a constant speed by altering the blade angle
As the angle of attack increases, what makes the stagnation point on the wing's profile
As the angle of attack increases, the stagnation point on the wing's profile moves downwards.
Does the pitch-angle of a constant-speed propeller alter (ändern) in medium horizontal turbulence?
Yes slightly
For a given angle of attack, a swept wing will: => Lift compared with straight one
have a lower lift coefficient than an equivalent straight one.
Drag Polar; Was sagt diese aus?
Anstellwinkel => grlsser als 0 => Lift b= Berthilde
The location of the centre of pressure of a positively cambered aerofoil section at increasing angle of attack will:
shift forward until approaching the critical angle of attack.
Aus Drag Polar folg ?
Drag curve => Wiederstandskurve => total Drag nimmt mit v^2 zu
The lift coefficient of an aerofoil section: Increase in AOA
Increases with an increase in angle of attack up to the stall.
Drag Curve ist das selbe wie?
Thrust Curve => max. Schub denn ich benötige => Tr (Thrust required)
The centre of pressure of a symmetrical aerofoil section is behind the leading edge approximately at the following % of the section chord:
25%
Aus Drag Curve / Thrust Curve leitet sich welche Curve ab?
Power Curve => Leistungskurve; wie viele Leistung ich benötige Pr = power required => Leistung P = Work/Zeit ==> wächst mit der v^3
==> Pr = Tr * v = D * v Tr = Thrust D = Drag
Aspect ratio of a wing is the ratio between:
wing span squared and wing area.
Unterschied Thrust (Tr) and Power (Pr)
Thrust: Bei piston engines => Thrustlever = Bewege ich den Thrust => Ich bewege den Thrust
Power (Leistung): bei Kolbenmotoren => Powerlever => nach vorne = mehr Fuel = Mehr Leistung = Drehzahl wird erhöhet = Propeller dreht schneller = Dadurch entsteht Schicht
==> Dreht schneller = v steigt => Angle wird kleiner => CL wird keliner ==> Muss schneller drehen = Irgend wann ist er an seinem Max.
An aeroplane maintains straight and level flight while the speed is doubled. The change in lift coefficient will be:
x 0.25
-
- 1 / 336
-
Flashcards
the min. speed at which lift equals weight is calles
VS1g
When looking at the airflow over the wing, from the wing surface and up, the air is:
With increasing AoA the CP will reach its most forward point :
Which aeroplane design has the highest probability of a super stall?
the purpose pf a fixed spoiler on the leading edge of a wing at the root is to:
The load factor is less than 1
1) stall speeds are determined with the CG at the forward limit
2) Min. control speeds are determined with the CG at the aft limit
1 and 2 correct
A fixed staal strip on the leading edge of teh wing at the root will:
Accelerated STall:
deep staal:
Accelerated STall: the staal that occurs while teh aircraft is experincing a load factor higher than 1 g ==> staals at higher speed
deep staal: dangerous => that affects certain aircraft designs, notably those with a T-tail conf. the turbulent wake of a stalled main wing blankets the horizontal stabilizer, rendering the elevators ineffective and preventing the aircraft from recovering from the staal => AoA between 40-60 degrees
fixed spoiler ?
a stall strip on the leading edge => the sharp leading edge of the stall strip ensures a lower stalling angle than the rounded leading edge of the wing and thus inducing stall
Staal speed increased => Formel mit Gewicht
V s new = vs old x Wurzel( new weight/ old weight)
WIe verhält sich die stalling speed mit der Höhe ?
constant at low altitudes as long as the speed is low enough for compressibility effects not to be present ==> stall speed Increased with altitude increasing
Wing forces => what theay do?
prevents the outward draft of the boundary layer and thus reduces the tendency to tip stall => higher AoA
what makes the tailplane?
normally produces a downwards force => when the tailplane stalls, the downward force will be gone immediately and the aeroplane pitches down
Difference straight and swept wing on stalling speed? Anhedral and T-Tail?
Anhedral and T-Tail no influence on stalling speed => wing sweep causes the Cl curve less slope and a smaller value of CL max than straight wings => the higher sweep, the lower the value of CL MAX = a higher stall speed
What is a spin?
a spin is a controlled or uncontrolled manouevre, = stalled situation (both wings are stalled) with the nose usually pointed sharply downwards in which the aircraft descends in a helical path with an AoA greater than the Angle of max. lift => Occurs with teh wings in a stalled flight condition plus a yaw and roll n the same direction and that it can develop in any attitude, at any airspeed at/or below manoeivering speed
