POF
T1
T1
WIth a turbofan ngines have no critical engine except the outher ones at a 4-engined aeroplane. By a crosswind T/O which one is the critical one?
the engine one on the windward side is the critical engine
3 options how to fly after an engine failure (small aircraft)
1.=> keeping the wings level => Rudder + aileron towards good engine=> The ball is centered => sideslip greates a large amount of drag
2. bank towards the good engine => ONLY AILERON => Rudder neutral => sideslip greates a large amount of drag
3. slighz bank and moderate rudder towards goo engine => straight ahead with minimum drag => no sideslip
=> minimum drag, no sideslip ====> the ball of the turn and slip indicator is not centered, but there is no sideslop => Bank angle max. 5 degrees
how to fly after engine failure big aircraft
a) larger power surplus
b) jet aeroplanes is linked with spoiler deflection which increases drag
=> then rudder is applied to teh side of teh operating engine which keeps aileron input at almost zero with the spoilers retracted => sideslip towards the side with the dad engine
VMCG
Minimum controlled speed on the ground => Flaps T/O
VMCA
Minimum controlled speed in the air => Flaps T/O, Gear up
VMCL
Minimum controlled speed for landing
Why is an aft, why a forward C.G. limit established?
aft: stability fwd: controllability
The static margin is equal to the distane between:
the CG and the NP
When the CG is close to the forward limit:
very hight stick forces are require for pitch because the aircraft is very stable
Dihedral angle is:
the upward and outward inclination of the main planes to the horizontal datum
helix angle
angle between the rotational speed and relative speed
pitch angle propeller
Angle between rotational speed and chord line
reference point propeller
where the resultant thrust force of a bald acts
Geometric pitch
distance a propeller should advance in one revolution
propeller: feather position
lowest drag for the aeroplane => 90 degrees => used on a failed engine of a multi-engine aeroplane to keep draw as slow as possible
propeller: Cruise pitch
between coarse (high pitch) and fine (low pitch)
propeller: Ground fine
the thrust is approximately zero => aeroplane is not moving
propeller: full reverse
max reverse thrust
propeller: Why is the pitch angle high at the root and low at the blade tip ?
to maintain the optimum AOA from the blade root to the blade tip
If teh aircraft is properöy loaded the CG, the neutral point and the manouvre point will be in the order given, forward to aft?
CG, neutral point, manoeuvre point
accelerate
beschleunigen
equidistant
gleich weit entfernt
obtain
erhalten
increase
zunehmen
dynamischer Druck
1/2 * p(Roh) * v^2
Lift in Newton
dynamischer Druck (1/2 * Roh * v^2) * s (Fläche) * CI (Koeffizient)
Kraft F in N
influence that causes a body to undergo a certain change in movement. ⇒ F (N) = m(kg)* a(m/s^2)
Arbeit (W)
Work (W)= Force x Distance Unit = Joule (J)
Leistung (P)
Power = Force x Velocity Unit = Watt
Gravitationskraft:
9.81 m/sec2
shape of an airfoil
Profil eines Flügels
Vektor:
Vektor: Grösse, welche auch durch ihre Richtung bestimmt ist
Weight:
Weight: the gravitational force onto a body. ⇒ In N
Mass:
Mass: the resistance that a body exhibits in response to a force which acce-lebrates or slows down the body Masse ⇒ Materie in a body
Acceleration
Acceleration: The rate at which the speed of an object changes = Beschleunigung ⇒ a = F / m
Coanda Effekt:
Coanda Effekt: ein strömendes Fluid mit Kontakt mit einer gebogenen Ober-fläche hat die Neigung der Biegung der Oberfläche zu folgen
Dichte (p) =
Masse pro Volumen = Mit zunehmender Höhe = Dichte nimmt ab è Hohe Temperatur + hoher Airport = selten gut p (N/m2) = p (kg/m3) * Rair * T(K) Rair = 287
atmospheric pressure =
weight of air column / area
totaler Druck
• Totaler Druck (pt): statischer (q)+ dynamischer Druck (ps)
Das Trägheitsgesetz = Gerade aus fliegen
Jeder Körper verharrt in Ruhe oder behält eine gleichförmige, geradlinige Bewegung bei, solange keine äussere Kraft auf ihn einwirkt, oder die äusse-ren Kräfte im Gleichgewicht sind d.h. sich gegenseitig aufheben
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Lernkarten
Bank angle
angle between the aeroplane lateral axis und the globe (Grund)
primary controls
1. Elevator 2. ailerons 3. rudder
2 different principles exist to change the control forces
1. changing the aerosol camber => Change in pressure distribution => downward deflection 2. changing the angle of attack by changing the and glee of incident => Ganzer Horizontal stabilizer drehen
The further forward teh centre of gravity, the larger the required
the larger the required tail-down force
Elevator controls
1. pitching 2. angle of attack 3. airspeed
In order to maintain straight and level flight at a constant airspeed, whilst the flaps are being retracted, the angle of attack will
Increase
retract
zurücknehmen
During the extension of the flaps at a constant angle of attack the aeroplane starts to (all other factors of importance being constant)
climb
anti Balance Tab the deflection are too
weak to control the aeroplane
flaps => Centre of pressure nach hinten => Nase down
Jedoch auf der anderesn Seite flaps produzieren höheren Downwash => reduces AOA => Force leads to an eroplane nose up ==> Welche Kraft dominiert?
depends on the flap type, position of the wings and the kind of tailplane
flaps result in an increase of lift at the same AOA => Stall speed is reduced => Fowler flap coefficient can be twice as high as with clean aerofoil ==> Welche flaps sind am Besten?
vgl. Bild
Speziell an Slats
Produzieren viel Lift, jedoch creatingt not too much drag
slots also colled
Krueger flaps
Unterschied Slats/SLots
Slats: extend-/rectractable leading edge device Slots: non-retractable leading edge device
Flaps und Slats zusammenhang
Slats==> increases maximum Lift Coefficient + reduce the stall speed Flaps: decreace AOA
Accererate
beschleunigen
In gerneral terms lift is a result of
a reduction of pressure over the wing
What statement is correct about the danymic pressure
Dynamischer Druck wächst mit dem xy der xy
Dynamischer Druck wächst mit dem Quadrat der Geschwindigkeit = p = V^2
velocity
geschwindigkeit
Lift is generated when
the flow direction of a certain mass of air is changed
Aspect ratio
Fläche
VMD Speed
minimum drag speed
Was ist der aerofoil polar ?
a graph of the relation between the lift coefficient and the drag coefficient.
Flapps werden eingetzogen /Retract), AOA wird
grösser
CL
lift coefficient
CD
drag coefficient
Which location on the aeroplane has the largest effect on the induced drag
Wing tip
Floating due to ground effect during an approach to land will occur:
when the height is less than the length of the wing span above the surface.
Increasing dynamic pressure will have the following effect on the drag of an aeroplane (all other factors of importance remaining constant):
at speeds greater than the minimum drag speed, drag increases.
Induced drag is created by the:
spanwise flow pattern resulting in the tip vortices.
Compared with the clean configuration, the angle of attack at CLmax with trailing edge flaps extended is:
smaller
If the nose of an aeroplane yaws left, this causes:
roll to he left
Flapps are extetended AOA wird
kleiner
The dihedral wing causes:
Lateral stability about the longitudinal axis
Compared to straight wings, swept wings have
Better directional stability
to oscillate
schwingen
Polyhedral wings?
vgl Bild
Was heisst ein Stabiles Flugzeug?
ability to return to its original state of flight without pilots action after the flight has been disturbed by a gust or a control input
Positive Statically stable
return to the initial state
