Thrust And Power Flashcards
Thrust is greatest when
Brakes released (output constant/input Varys (low when not moving)
Ram Effect
Increases thrust due to mass flow increase when compressibility of air begins
Momentum Drag
The thrust lost from increase in speed - air entering increasing but exit speed constant
Flat Rating
ISA +15 degrees
RPM limited with temperature
TOGA is limited to
10 minutes with engine failure
5 minutes for all engine operations
Power Available
Thrust x Velocity (TAS)
Power Required
Drag x velocity (TAS)
Varies with induced drag/parasite drag
Power Vs Thrust graph shows
Thrust is almost constant against TAS
Power is 0 at brakes release and increase with TAS
VMP =
VMP = 0.76 x VMD
Fuel flow formula
Kilograms
—————
Time (Hour)
Propeller - Power x SFC
Jet Engine - Thrust x SFC
SFC
Specific fuel consumption
Proportional to temp/alt/pressure
Not influenced by the speed/config/weight of aircraft
How much fuel required to produce thrust
Thrust is limited by (Jets)
RPM and Temperature
What speed is propeller thrust maximum
Zero Speed
SFC Formula
Fuel flow
————
Thrust
Specific Range Formula
True Airspeed
——————-
Total Fuel Flow
Specific Ground Range Formula
GS
——-
Fuel Flow
Factor that influence VMC
Higher thrust the larger the asymmetry = higher VMC
VMC in a descent
VMC increases as more power/thrust = larger asymmetry
High Altitude on VMC and V1
VMC and V1 reduces
Density is low/lower thrust/longer acceleration
V1 = highest speed to abort/more runway so needs to be less to stop
Low Altitude on VMC and V1
VMC and V1 increase
Factors reducing V1
Runway wet/slipper/contaminated
Higher altitude
