I.F Performance and Limitations

What are some limitations of our aircraft?

Va - 111

Vfe - 103

Vs - 44

Vno - 126

Vne - 160

Service Ceiling

Absolute Ceiling

Engine Limitations - 2700 RPM

Weight Limitations - 2325 lbs

Fuel

CG Limitations

What’s the difference between absolute ceiling vs service ceiling?

Service ceiling - maximum rate of climb is 100’ per min

Absolute ceiling - maximum rate of climb is 0’ per min

Absolute ceiling is higher

What is manevuering speed?

the limit load can be imposed without casuing structural damage to the airplane

How can you calculate the maneuvering speed for your aircraft?

Va @ Max Gross x [square root (your weight/max gross)]

Where would you find performance data for your specific airplane?

under “Performance” section in the POH

Describe Vx and Vy and how they differ

Vx - best angle, obtains highest altitude in a given distance (distance)

Vy - best rate, obtains highest altitdue per unit of time (time)

What’s the difference between Vs0 and Vs1?

Vs0 - Power-off stalling speed, landing config

Vs1 - Power-off stalling speed, clean config

How will the climb rate of an airplane differ on a hot vs cold day?

As Temp increases, the air becomes less dense.

On a hot day, the air is less dense, and climb performance decreases

The opposite is true for a cold day, more denser, increased climb performance

How will our aircraft perform at a high elevation airport on a hot day?

The aircraft will perform worse compared to departing at sea level on a cool day due to the high density altitude

What is Density Altitude?

Is pressure altitude corrected for nonstandard temperature

Can we change the camber of our wing?

Yes, by extending or retracting the flaps

What happens when we extend our flaps from a clean configurations to flaps full?

lift is increase and induced drag is increased.

We get a steeper descent without increasing airspeed

What can we expect to happen if we are taking off from a runway with a .6% incline?

longer take off roll

How would you describe the Center of Gravity?

where the aircraft would balance if suspended

Essentially, the weight of the airplane is concentrated

What are some results of having a more AFT center of gravity?

Higher Cruise speed

Higher Stall speed

Less stable

adverse stall recovery

What are some results of having a more FORWARD center of gravity?

Slower cruise speed

Lower stall speed

More stable

More favorable stall recovery

What is the purpose of maneuvering speed?

So the plane will stall before reaching its limit load factor and damage the structural integrity of the aircraft.

We want to fly at or below maneuvering speed

Why might our actual performance be different or worse than the manufacturer’s performance charts and tables?

They’re published by the manuefacturer are obtained using test pilots with new aircraft.

Actual performance by a student pilot in a rental aircraft may not be the same

What are the four forces of flight?

Lift, weight, thrust, drag

Describe the relationship between thrust and drag?

They’re equal at a constant airspeed

Decelerating the airplane means, thrust < drag

Accelerating, trust > drag

Describe the relationship between lift and weight

They’re equal when at a constant altitude

When climbing (increasing altitude), lift > weight

When descending (decreasing altitude, lift < weight

When are the two basic types of drag?

Induced drag

Parasite drag

What are the different types of parasite drag?

Form drag

Interference drag

Skin friction drag

What is form drag?

due to the shape of the airplane and airflow surrounding it

What is interference drag?

generated due to the intersection of airstreams that create turbulence and restrict smooth airflow

What is skin friction drag?

Generated by aerodynamic resistance of air in contact with the surface of the airplane

What is Parasite drag?

Composed of all the forces that work to slow an airplane’s movement

What is induced drag?

byproduct lift. the production of lift causes induced drag through wing tip vortices

What are wingtip vortices, and how do they form?

Circular motion of air around the tip of an airplane’s wing.

Due to the pressure difference between the upper and lower surfaces of an airfoil.

With Low pressure on top of the wing and High pressure under the wing

Because high pressure always follows low pressure, vortices are formed around the wing tips

What are the axes of flight and what causes motion about them?

Longitudinal axes - nose to tail, uses ailerons to roll

Lateral axes - left to right, elevator/ stabilator to control pitch

Vertical axes - bottom to top, rudder to yaw

All three axes act through the center of gravity of the aircraft

What are the four left turning tendencies?

Torque

P force

gyroscopic precession

Spiraling slipstream

Explain why rudder must be used in turns to maintain coordinated flight

Yoke is turned to enter bank, the outboard aileron deflects downward to increase lift on that wing.

The increased lift causes more induced drag on that wing which causes the nose to yaw towards the outside of the turn.

To maintain coordinated flight, you must input rudder control towards the inside of the turn when entering it

What design methods can be used to combat increased induced drag during turns?

Differential ailerons

Frise-type ailerons

Coupled ailerons

Flaperons

What are Differential ailerons?

the “up” aileron raises higher than the other aileron goes “down”. This causes increased drag on the inside wing and helps combat adverse yaw from the induced drag on the outside wing

What are Frise-type ailerons?

cause the aileron being raised to have the bottom portion of the control surface project into the air flowing below the wing.

This causes an increase in drag on the inside wing

What are coupled ailerons?

has an “interconnect” between the rudder and ailerons which causes the rudders to automatically move when the controls are turned

What are Flaperons?

Combines both aspects of flaps and ailerons. Acts as conventional ailerons, but also can be lowered like flaps

Why must you apply a nose-up input to the controls while in turns?

Without a nose-up command, the total lift produced remains unchanged. The lift vector no longer points up, but off at an angle. The aircraft’s weight remains unchanged, and there’s now not enough “vertical” lift to offset the weight of the aircraft.

Nose up controls increase angle of attack to produce more lift to combat the loss of the vertical component of lift in turns