Performance and Limitations - SGRs Flashcards
As air becomes less dense, aircraft performance is reduced among these 3 factors
Reduced power since engine takes in less air
Reduced thrust since propeller is less efficient in thin air
Reduced lift since thin air has less force on airfoil
Standard day at sea level (F, C, Hg, Mbs)
15C 29.92Hg
59F 1013.12 Millibars
What is the standard temperature lapse rate?
It is accurate to what altitude?
2C/1000 feet
to 36,000 feet
What is the standard pressure lapse rate?
It is accurate to what altitude?
1 in Hg / 1000ft
to 10,000 feet
Pressure altitude is important for…
determining aircraft performance
Pressure altitude is determined by
- Setting Baro to 29.92 and reading indicated altitude
- applying correction factor to indicated altitude according to reported altitmeter
- using a flight computer
Density altitude defined
Pressure altitude corrected for non-standard temperature
Plane performs according to what type of altitude?
Density
Air density is affected by changes in…
altitude
temperature
humidity
At constant temperature air density is _________ to pressure. aka How are air density and pressure related?
Directly proportional
How is density of air and temperature related?
Inversely
Increase in humidity causes a ______ in air density
decrease
Relative humidity defined
Percentage of maximum amount of water vapor the air can hold
Can warm air or cold air hold more water vapor?
Warm air can hold more water vapor
Is water vapor heavier or lighter than air vapor?
Lighter
When landing at high elevation airports the IAS for approach and stall is the same. What is different?
TAS is faster Ground Speed is faster Longer approach, longer rollout Greater distance to clear obstacles Longer runway needed
What are the main aircraft performance characteristics?
Takeoff and Landing Distance Rate of Climb Ceiling Payload Range Speeds Maneuverability Fuel Economy
Induced Drag defined
Induced Drag varies by
Induced drag is the total drag created by production of lift
- increasing with airspeed
- because at lower airspeed higher AOA is required = greater induced drag
Parasite Drag defined
Parasite drag varies
Parasite drag is drag from friction of air over the aircraft structure
varies directly with airspeed
Double the airspeed. What happens to parasite and induced drag
4x greater parasite drag (8x power needed)
1/4 of original value for induced (1/2 power needed)
Service ceiling defined
Can service ceiling always be reached
maximum density altitude where best rate of climb airspeed is 100FPM climb
No. Service ceiling may not be reached due to actual density altitude
Climb performance is a result of what two energy types?
Excess power above that required for level flight.
Aircraft’s kinetic energy (trading airspeed for climb)
Absolute ceiling defined
altitude where climb is no longer possible
Power loading formula
results in ____/_____
weight of plane/ HP of engine
lbs/hp
Wing loading formula
results in ____/_____
weight of plane / wing area (includes ailerons) in sq ft
lbs/sq. feet
Why is power loading important?
Why is wing loading important?
Power loading is important for takeoff and climb capability
Wing loading is important for determining the landing speed.
Maximum range defined
Maximum range obtained at what point?
max distance flyable for a given fuel supply
L/D max
Maximum endurance defined
Maximum range obtained at what point?
max time flyable for a given fuel supply
minimum power (lowest fuel flow)