Exam 2 Flashcards
what are the two aircraft engine types
Reciprocating
turbo powered
Heat engines
utilize heat energy to produce the power for propulsion
Kinetic energy
energy in motion
potential energy
energy of position or stored energy
Normal category G rating
+3.8
-1.52
Utility category G rating
+4.4
-1.76
Acrobatic Category G rating
+6
-3
Positive G Loads
pull back on the control wheel stick
centrifugal force acts in the same direction as weight
makes you feel heavier
Negative G load
Push the stick or control wheel forward
centrifugal force acts in the opposite direction as weight- an upward force on the aircraft
makes you feel lighter
Load factor
ratio of the total load supported by the wing compared to the weight of the aircraft
load factor increases as
bank increases
what are the two kinds of stability
static
dynamic
the vertical stabilizer and swept back wings help maintain _____ stability
yaw
Camber on the bottom of the tail uses Bernoulli Effect on the bottom of the horizontal stabilizer, and creates ____
negative lift
what are the 6 flap types
basic
plain
split
slotted
fowler
slotted fowler
droop leading edge
lower the AOA and gives the wing a higher camber s the air sees it
Kreuger Flaps
another leading edge device
lower the AOA, increase camber and more rounded leading edge
effective aspect ratio
gives the wings characteristics of a higher aspect ratio
high aspect ratio wings produce less drag
things to do to prevent wingtip vortices (better aspect ratio)
drooped wing tips
end plates
fuel tanks
missile launchers
winglets/ sharklets
joined wings
forward swept wings
Leading edge slat
slotted leading edge slat
better lift/ drag ratio high wing
better lateral stability
shorter landing distance
better lift/ drag ratio low wing
easier to build strong landing gear support
better roll maneuverability
shorter take off distance
which wing configuration is most susceptibal to ground effect
the one with the wings closest to the ground
Horizontal stabilizer Tee Tail advantages
keeps horizontal stabilizer and rudder out of the main wing downwash
horizontal stabilizer tee tail disadvantage
vertical stabilizer must be larger and heavier
Horizontal Stabilizer: Vee Tail advantages
decrease interference drag by eliminating the number of acute angles, typically lighter and less wetted surface, drag is reduced, increase stealth
Vertical Stabilizer: Vee tail diadvantages
require a much more complex control system, required to be structurally more robust, control forces required for operating the ruddervators are higher
different placement of vertical stabilizer why?
fuselage tends to block the airflow to a normal single c=vertical stabilizer and rudder
fighters often have 2 tails for this reason, more control
flying wires BiPlane
transmit the left back to the fuselage
landing wires BiPlane
transmit the downward impact of landing, or negative G loads, on the wings back to the fuselage
Interplane struts
transmits the lift loads and landing loads between the top and bottom wings
Cabane struts BiPlane
support the top section of wing above the fuselage and transmits the lift loads of the wing roots to the fuselage
The Center Section BiPlane
an airfoil-shaped section above the fuselage to which the upper wings attach
Interplane interference
airfoils flying in proximity reduce differential in psi
the gap between the BiPlane wings
the distance between the top chord and the bottom chord of the 2 wings. must be 1 chord length
Interplane interference affected is by
Decalage
Decalage on a fixed-wing aircraft is
the angle of difference between the upper and lower wings of a biplane
Tandem Wing
both wings lift up and there is no horizontal stabilizer pulling down
very limited center of gravity range
very limited center of gravity
what is a canard wing
a special type of tandem wing
canard should carry no more than 25% of the total weight
canard wing stalls before the other wing
very lfit efficient
Flying wing
drag is greatly reduced,
stabillity is hard
have to worry about center of gravity moving left and right
what did wing airplane need
spit rudders
elevons
this gave us much more stability and replaced out tail
what are ruddervators
Vee tails
____________ does not apply at supersonic speeds because____
Bernoulli’s principle
his principle assumes that air is not compressible and at super sonic speeds we need to understand that air is a compressible fluid
as airflow approaches sonic speeds, air becomes
a compressible fuid
why does the speed of sound change at altitudes
it changes based on
cold molecules move slower
standard day 760 mph
sonic boom
a loud sound kind of like an explosion
caused byyour plane moving air out of its way and it following the plane
happens when you are faster than the speed of sound
Mach number
the speed of the aircraft in relation to the speed of sound
mach calculation
true speed of the aircraft/ speed of sound
subsonic
any region below the transonic region or below the critical Mach number
Transonic
begins with teh first evidence fo localized sonic or supersonic airflows and begins at the critical mach number. Transonic region ends when all flows around the aircraft are fully supsonic
Sonic
right at the speed of sound
supersonic
any speed faster that the speed of sound
hypersonic
any speed above mach 5. Plasma effects begin to affect airflows
the transonic region begins with
the first evidence of sonic or supersonic flow around the aircraft
transonic flow creates
the most drag on a high speed aircraft
Mcrit
when some flows are supersonic and some are subsonic you are flying in the
when you enter transonic regime
shock waves
air at supersonic speeds is compressed because the air no longer has enough energy to be able to get out of the way of the aircraft, the air molecules get shoved together and compressed, the air compresses, builds up, and sticks to the wing
two types of shock waves
normal
oblique
split flap
adds some lift and drag
slotted flap
lift is increased greatly
drag slightly
Fowler Flap
increases drag
Normal Shock Wave
perpendicualr to flow direction
shock wave absorbs energy from the air and causes tremendous drag
Oblique shock wave
wave consumes some of the energy from the air and creates some drag
how is lift made
lift is generated only by the angle of attack
how does design effect shock waves
The flatter upper camber will keep the airspeeds across the wing lower than that of a normal cambered wing
Lowest pressure orces on a supercritical wing are also concentrated around the highest camber
how does thrust, drag, lift, and weight work together in a helicopter
thrust and lift work upwards together
weight and drag work downwards together
Collective stick
moves the helicopter vertically
changes the angle of attack of all blades at the same time
pulling up gives all blades a larger angle of attack so they take bigger bites of air
cyclic operation
controls movement forward, backward, etc
it changes the blade pitch at only one part of its rotating cycle which tips the rotor disk forward and moves the helicopter
when pushing forward the blade in the back will always have the higher angle of attack which will move you forward
helicopter rotors run at a constant ___ in flight
RPM
with no centrifugal force from rotation to hold them straight the rotors will ______ when they are not spinning
droop
the spinning rotor blades generate a _____ that keeps the blades stretched out straight and prevents the blades from folding up or breaking
centrifugal force
Coneing
blades pull up or cone when they are spinning and put under a lift load
what control the direction a helicopter is facing
anti-toque pedals
what is the tail rotor controlled by
foot pedals
a lot like the rudder of the plane
what are foot pedals also called
anti-torque pedals
the tail rotor also counteracts the
torque of the spinning main rotor blade
what happens if the tail rotor quits
the helicopter spins around in a circle in the opposite the direction of the main rotor
what is something we can put on a tail rotor
Fenestron
it is a device that covers the tail rotor
on the fenestron for aerodynamic efficiency, the shroud is
rounded at the upstream air intake and flared downstream
good for small and medium helicopter
what is the best thing about fenestron
greatly reduces injuries due to tpeople running into tail rotor, and reduces accident where tail rotors strike objects
eliminating tail rotors
greatly reduces noise and improves safety
only works on small helicopters
NOTAR-because torqu to fuselage changes as main rotor blade pitch changes
the engine runs at a constant RPM
a fan with variable pitch blades is put in front of the tail boom to force air into the boom
NOTAR- as more main rotor pitch is used and more anti-torque is needed
the fan changes pitch automatically increasing the flow of air out through the slot in the starbourd side of the tail
control surface
movable airfoil on any surface
primary flight controls
elevator, rudder, ailerons
Secondary flight controls
modify the effects of the primary flight controls or air flows
Primary flight control airleron
controls roll
longitudinal rotation about the longitudinal axis
lateral stability
Primary flight control: elevator
controls pitch
rotation about the lateral axis
longitudinal stability
Primary flight control: rudder
controls yaw
rotation about the vertical axis
directional stability
how do ailerons work
turn the yoke in the direction you want to go
the airleron in the direction you turned will go up and the opposite will go down
the down airleron will create more lift creating a turning tendency
Slipping turn
need to add more rudder
skidding turn
need to add less rudder
adverse yaw how do you fix it
differential ailerons
the aircraft may roll one way but directionally turn the opposite as a result an imbalance of drag at the wingtips between the left and right wing
differential aileron fix this, the up aileron will raise more so that it catches more air than the down aileron which will equal out the drag
Flaps
a high light/high drag device, improve the lifting ability
Slats
a high lift device typically found on jets, mounted don’t eh leading edge, change the camber and curvature of the wing to improve lifting ability at slower speeds
Secondary flight controls: trim tabs
used to get flight control setting jsut right, little tabs often found on the rudder, elevator, and airleron
Secondary flgiht controls: flgiht spoilers
kill lift, they are not speed breaks, mounted on the upper surface of the wing and when extended increase drag and decrease lift by disrupting airflow
Secondary flight controls: ground spoilers
maximinze wheel brake efficiency
flight spoilers are often ground spoilers
Secondary flgiht controls: speed brakes
not spoilers, used to create drag to slow the airplane, mostly fuselage mounted panels
