Takeoff Power And Performance Flashcards
Lift off speed (Vlo)
Point At Which Airplane Is Ready to Fly
Just Above Stall
CL = CLmax
Vlo = 1.2Vso
Newton’s second law
Acceleration
●Proportional to the Sum of Forces
●Inversely Proportional to the Mass of the Object
Thrust during takeoff
Decreases As Velocity Increases For Propeller Driven Airplanes
Drag during takeoff
●Parasite at Beginning
●Induced & Parasite at End
●Increases As Velocity Increases
Rolling resistance
●Characteristic of Surface
●Force Acting Normal to Runway
●Decreases As Velocity Increases
Minimize ground roll
●Maximize Acceleration
●Minimize Vlo
Maximize acceleration
●Increase Thrust
●Reduce Drag
●Reduce Weight
●Increase Lift
Minimize Vlo
●Minimize Weight
●Maximize CLmax
●Maximize Surface Area
Takeoff variables
●Density
●Wind
●Runway Slope
●Pilot Technique
What conditions affect a planes performance
●Density altitude
●Pressure Altitude
●Atmospheric Composition
Effects of pressure
●Higher pressure = better performance
●Lower pressure = worse performance
At standard temperature, pressure is proportional to density
●Pressure is doubled, density is doubled
Effects of density
Increasing the temperature of a gas, decreases it’s density
Decreasing the temperature of a gas, increases it’s density
Density of the air varies inversely with temperature, given pressure remains constant
Atmospheric composition
Humidity (moisture)
●Water vapor is lighter than air
Moist air is lighter than dry air
More water vapor in the air = less dense air
Relative Humidity (RH)
●How much moisture air can hold
Density
●Temperature
High Temperature - Low Density
●Pressure
Low Pressure - Low Density
●Dry Air - Heavy
●Moist Air - Light
●High Humidity - Low Density
Low density
●High Altitude
●Low Pressure System
●High Temperature
●High Humidity
Density variables
●Powerplant Performance
●Takeoff Velocity
●Thrust
Power plant performance
●Reduced For Non-Turbocharged Airplanes
Takeoff velocity
●Depends On Dynamic Pressure
●Same IAS, Higher TAS
Wind
●Airplane Starts Takeoff Roll With Velocity Equal to Headwind Component
●Reduction in Takeoff Distance Not Linear
Wind, surfaces, and contaminants
A 10% reduction in takeoff distance can be applied for every 9 KTS of headwind, and a 10% increase can be applied for every 2 KTS of tailwind.
A 15% increase in takeoff distance can be applied to dry grass runways; runway contaminants such as long grass, sand, mud, slush, standing water, or snow can easily double the takeoff distance.
A 10% decrease in weight will result in a 10% decrease in the takeoff roll, while a 10% increase in weight will result in a 20% increase in the takeoff roll.
Runway slope
Upslope - Retarding Force
Downslope - Accelerating Force
Pilot technique
●Lift Off Speed
Higher Speed Increased Distance
●Distance = (velocity)2
Lower Speed Increased Distance
●Induced Drag
●Use of Flaps
Increase CLmax
Lower Vlo
Reduced Takeoff Distance
●Use of Flaps
First Half of Flap Travel
●Big Increase In Lift
●Small Increase In Drag
Second Half of Flap Travel
●Small Increase In Lift
●Big Increase In Drag
●Use of Flaps
Do Not ‘Pop’ Flaps
●Pilot Distraction
●Rolling Resistance Biggest Factor At Start of Run
Normal takeoff
Set Takeoff Flaps
Center Airplane On Runway
Advance Throttle Smoothly
Check Engine Instruments
Maintain Directional Control
Rotate At Recommended Airspeed
Accelerate To Vy - Gear Down
Retract Gear When
●Positive Rate of Climb Established
●Safe Landing Can No Longer Be Established
Maximum takeoff performance
Without Obstacle
●Minimize Ground Roll
With Obstacle
●Minimize Ground Roll
●Maximize Angle of Climb After Lift Off
Set Recommended Flap Setting
Position Airplane For Maximum Runway Availability
Center Airplane On Runway
Apply Brakes
Advance Throttle Smoothly To Maximum
Check Engine Instruments
Release Brakes
Maintain Directional Control
Rotate At Recommended Airspeed
With Obstacle
●Accelerate To Vx - Gear Down
●Climb Until Clear of Obstacle
Without Obstacle
●Accelerate to Vy - Gear Down
