PT2 CHP7 Weight and Balance Flashcards
What is weight and balance?
Refers to the control of the aircraft’s total weight and the location of the Center of Gravity (CG)
What can occur if you operate overweight and outside of the center of gravity’s limits?
Can lead to loss of control and accident
How will performance be affected as a result of more weight?
Undesirable performance
If an airplane is overloaded, what may occur?
It may not get off the ground (the aircraft can only create so much lift)
What changes throughout the flight and why?
Weight changes due to fuel being burned
How will weight affect takeoff (speed)?
Will require a higher speed to counteract weight and generate lift
How will weight affect takeoff (distance)?
Will require a longer roll due to needing more lift
How will weight affect altitude and why ?
Will reduce the maximum altitude due to reduced performance
How will weight affect range and why?
Will reduce range due to greater fuel burn
How will weight affect cruising speed and why?
Higher angle of attack, which will create more drag, so cruising speed is lessened
How will weight affect the stall speed and why?
Will require a higher angle of attack to create more lift, which leads to a higher stall speed
How will weight affect the landing roll and why?
Like takeoff roll, will require more runway length
What is balance control and why is it important?
It is the location of CG and is important because we want to maintain the stability and safety of the flight
What axis do we mainly focus on in relation to CG?
Longitudinal axis (lateral axis CG will change with fuel burn)
What is an “envelope”?
The limits the CG must remain within either forward or aft
What does a forward CG signify?
Nose-heavy aircraft
What does an aft CG signify?
Tail-heavy aircraft
What is Center of Gravity (CG)?
The point at which, if a string were attached, the object would be in equilibrium; the point at which WEIGHT is applied
What is Center of Pressure (CP)?
The point at which LIFT is applied
What are CG limits?
Specified forward and aft CG points within which the CG located
- What is CG Range?
The distance between the CG limits
What is Arm (A)?
The distance between the datum and where a force is applied
What is Datum?
An imaginary vertical line from which all arms are measure
What is station (Arm)?
-The location of an object in relationship to the datum (like the arm)
i. might be referred to as “Station 46”, which signifies the object is 46 inches from the datum
What is Moment (M)?
- The efficiency of a force
- Door example:
1. Handle further away from the hinges in the middle close to the edge, easier to open the door - Long arm means small force necessary
2. Handle close to the hinges in the middle of the door, harder to open the door - Small arm means large force necessary
What is the Moment (M) equation?
Moment = Arm * Weight
What is Standard Empty Weight?
Airframe, engine, all fixed operating equipment, hydraulic fluid, unusable fuel, and engine oil
What is Basic Empty Weight?
Standard empty weight + weight of optional equipment installed
What is payload
The weight of occupants, cargo, and baggage
What is fuel load?
All the useable fuel
What is the Useful load?
Weight of occupants, baggage, usable fuel (payload + fuel load)
What is maximum gross weight?
Basic empty weight + max useful load
Where can the aircraft weight and balance limits be found?
AFM (airplane flying manual) and POH (pilot operating handbook)
- What will affect the weight restrictions of the aircraft? (3)
- Temperature
- Elevation
- Humidity
Describe the relationship between the Center of Gravity (CG) and Center of Lift (CL) when the CG is centered and CL is aft in a balanced configuration
- The center of lift (CL) is aft of CG (point which all axes pivot), the center of lift (CL) causes a nose-down movement
- The tail down force (horizontal stabilizer “upside down wing” produces downward/opposing lift), which counteracts the center of lift (CL) nose-down movement
- The arm from the CG and tail down force is so far, only need a small force
Describe the relationship between the Center of Gravity (CG) and Center of Lift (CL) when the CG is moved aft and close to the CL?
- CG moved aft closer to center of lift (CL)
- The arm between CG and CL has reduced
- The moment also reduces
- We need a lot less taildown force
- What are the positive and negative effects of aft CG?
- Positive: higher cruise speed, increase range, shorter takeoff distance
- Negative: decreased stability, possibly uncontrollable, over rotation on takeoff, over flaring on landing, lower stall speed
