Seminole Systems Flashcards
Which engine?
reciprocating engine - converts chemical to mechanical energy
lycoming
direct drive
4 cylinder
horizontally opposed
propeller produces thrust
2700RPM at sea level 2 props
180 HP per engine
counterrotating (left clockwise, right counterclockwise)
turbojet/turbofan vs reciprocate/turbopros
turbojet/fans increase air velocity thru engine increases thrust
abnormal combustion definition and causes
- uncontrolled explsoive ignition of fuel-air mixture within combustion chamber
- can lead to piston, cylinder or valve failure if not corrected
- engine overheating, roughness, loss of power
causes:
- burning lower fuel grade
- high manifold pressures with low rpm
- high power setting, lean mixture
- extended ground operations
- steep climbs
whats preignition
fuel-air mixture ignites before normal igntion, caused by residual hot spot (small carbon deposit, cracked spark plu insulator; other damage inside cylinder) in combistion chamber
fine vs coarse vs feathering
more oil pressure as prop going fwd, higher RPM
fine pitch - climb
coarse - cruise
feathering - least drag
what is the counterweight, spinner dome, low pitch stop in the nose
prop governor functions (2) and how
regulates oil into and out of prop
- change prop blade angle
- maintain constant RPM as air load on the properller changes
speeder spring, pilot valve, fly weight
Propellor pitch is affected by five factors for high/low pitch
low pitch - take off and clilmb
high pitch/low rpm:
nitrogen gas
feathering spring
counterweights
low pitch/high rpm:
oil pressure
propellor blade aerodynamic twisting foce
underspeed vs overspeed
windmilling
causes drag, relative wind strikes face of prop
feathering and feathering lock
nitrogen, feathering spring and flyweights are used to feather the lock
feathering lock
- for engine start and shutdown
- easy start
- cannot be feathered anytime prop rpm below 950
accumulator
sends oil thru prop governor
after engine restarts, oil pressure, nitrogen recompresses the accumulator
landing gear uplock vs downlock
landing gear pump
electrically powered bidirectional (reversible)hydaurlic pump
landig gear schematic (4)
thermal relief: relieves pressure above 3000PSI caused by temp changes
shuttle valve: moes hydaruliic fluid to move actuators up/down
pressure switch: at 1800psi this switch shuts off hydraulic pump
restrictor: slows nose gear during retraction
gear retraction
held in place by hydraulic pressure
downloack siwtch
3 greens when down and locekd
how many landing gear switches
right squat switch - prevents stall horn and maintenance hobbs metar op
left squat switch - prevents landing gear retraction
up limit switch - uplimit travel for nose wheel
down lock switch - deactivates pump when gear is flly extended
hydraulic pressure switch - deactivates pump when landing gear is retracted
priming
can overprime engine
cylinder 3 is not primed
electric fuel pumps must be on to operate the electric fuel primers
crossfeed
allows fuel to flow from opposite side to operating engine
select OFF on failed engine
contaminated fuel, engine failture
do not takeoff or land with fuel selector on xfeed
PAST
P p factor (assymetrical thrust due to ascending/descending blade, slower more prominent)
A accelerated slipstream (airflow from thrust directly over the inboard portion of wing, lack of lift from the dead engine prop)
S spiraling slipstream (spinning air twisting around plane, lack of wind that hits rudder)
T torque (propeller turns right, airplane wants to roll left, high rpm)
blue sky black earth
climb move blue
descend move black
service ceiling vs single engine service ceiling
100fpm max density altitude where best rate of climb airspeed
single engine
50gpm altitude a twin engine airplane can no longer climb at a rate greater than 50rpm
single engine performance considerations
critical engine vs non critical engine
extended flaps or landing gear
aircraft weight
Cg location
what is a slip
a slip occurs when an airplane does not travel in the direction the nose is pointed
moves sideways than straight ahead
produces a large amount of drag
- want zero sideslip
