Performance

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# Performance - PowerPoint PPT Presentation

Performance. Atmosphere . 78 percent nitrogen 21 percent oxygen 1 percent other (helium, argon) Most oxygen is contained below 35,000 feet altitude. Atmospheric Pressure. As air becomes less dense, it reduces; Power, because the engine takes in less air

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## PowerPoint Slideshow about 'Performance' - eldon

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Presentation Transcript

### Performance

Atmosphere
• 78 percent nitrogen
• 21 percent oxygen
• 1 percent other (helium, argon)
• Most oxygen is contained below 35,000 feet altitude
Atmospheric Pressure
• As air becomes less dense, it reduces;
• Power, because the engine takes in less air
• Thrust because the propeller is less efficient in thin air
• Lift, because the thin air exerts less force on the airfoils
Atmospheric Pressure
• Standard at sea level: 59 Degrees F or 15 Degrees C, Surface pressure of 29.92, or 1013.2 millibars
• Standard Lapse rate:3.5 F or 2 C per thousand feet up to 36,000
Pressure Altitude
• Height above a standard datum plane (29.92)
• To find your pressure altitude:
• Set altimeter to 29.92 and read indicated
• Apply correction factor to the indicated altitude according to reported altimeter setting
• Ex. If the reported altimeter setting is 29.82, Subtract it from 29.92 (the standard altimeter) for a difference of 0.1, then multiply that by 1000 and add it to the altitude of the airport (845). Pressure altitude = 945 feet
Density Altitude
• Pressure altitude corrected for non standard temperature
• As density of air increases, it is considered a lower density altitude and vice versa (this is because you are lower to the ground)
• As density altitude increases, performance increases
• As density altitude decreases, performance decreases
• To find density altitude, you must take into account pressure and temperature, you do this when you use your POH to find your performance
Climb Performance
• Your ability to climb is dependent on excess thrust
• Rate of climb depends on flight speed and the inclination of the flight path
Climb Performance
• Absolute Ceiling
• Altitude at which you can no longer climb
• Service Ceiling
• Altitude at which you are unable to climb at a rate greater than 100 feet
Range
• How far you can fly on a specific amount of fuel (the furthest distance for the least amount of fuel)
• Max Range is obtained at the maximum lift/drag ratio, or L/D max
• Unaffected by weight or altitude
Endurance
• Most amount of time aloft for a given amount of fuel
• Max endurance given when at the point o fminimum power required since this would require the lowest fuel flow to keep the airplane in steady, level flight
Factors Effecting Range and Endurance
• Weight
• Density Altitude
• External aerodynamic configuration of the airplane
Ground Effect
• Interference in the three dimensional airflow around the aircraft
• Occurs within one wingspan of the ground
• Most significant when at a constant low altitude at a low speed in a low wing airplane
• Decrease in induced drag allows for greater performance
Region of Reversed Command
• “Back side of Power Curve”
• Power for altitude, Pitch for airspeed
• Low speed phases of flight
• Gravel
• Turf/muddy
• Potholes/rough pavement
• Uphill runway
• Downhill runway
• Obstructions
• Mud, snow, standing water
Hydroplaning
• Water reduces friction between the tires and the ground, reduce braking effectiveness
• Braking and Directional Control lost
• Higher speeds increase the hydroplaning hazard because the water can’t move out of the way fast enough
• Land into the wind, no abrupt control inputs, brake smoothly – use aerodynamic braking
Estimating Performance
• Most Performance charts assume that you are using a dry, paved runway in standard conditions.
• Your actual conditions as well as piloting experience will influence your actual takeoff and landing performance
• POH should still be used as a guide