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Performance and Limitations

Performance and Limitations

Performance and Limitations
Performance & Limitations

Objective: The student will be introduced to weight and Balance and the calculations. The student will be introduced to the performance of an airplane in different characteristics of flight.

Completion Standards: The student will be able to calculate a weight and balance with minimal help from the instructor. The student will be able to determine specific performance during different phases of flight.

References: PHAK CH 10-11, AC 120-27, POH

Equipment: White Board and markers, iPad/ computer, Weight and Balance 

IP’s Actions:

  • Assess student

  • State the objective and completion standards

  • Writes down references

  • Provide attention getter

  • Present content

  • Assessment

  • Assign Homework

SP’s Actions:

  • Take notes

  • Ask Questions

Introduction: 

(Attention Getter) : https://www.youtube.com/watch?v=FD1T97UqMMU&t=35s

Motivation: (Discuss purpose for lesson and relate to Attention getter)

Overview:

  1. Weight & Balance

  2. Use of performance charts, tables, and other data in determining performance in various phases of flight.

  3. Effects of exceeding airplane limitations.

  4. Effects of atmospheric conditions on performance.

  5. Factors to be considered in determining that the required performance is within the airplane’s capabilities.

Content:

Determination of weight and balance condition.

Weight & Balance

  • Compliance with the weight and balance limits of any aircraft is critical to flight safety.

  • Forces of aircraft

    • Lift

    • Weight

    • Thrust

    • Drag

  • Effects of weight

    • Higher takeoff speed

    • Longer takeoff run

    • Reduced rate and angle of climb

    • Lower maximum altitude

    • Shorter range

    • Reduced cruising speed

    • Reduced maneuverability

    • Higher stalling speed

    • Higher approach and landing speed

    • Longer landing roll

    • Excessive weight on the nose wheel or tail wheel

  • CG (limit)

    • Is a point at which the aircraft would balance

    • Changes in weight

      • Forward VS AFT

        • Nose heavy = potential for better stall recovery

        • Tail heavy = potential for no to late recovery

      • Side VS side


  • Stability

    • Nose-heavy condition causes problems

      • In controlling and raising the nose, 

      • Especially during Takeoff and Landing

    • A tail-heavy condition has a serious effect upon longitudinal stability, and 

      • Reduces the capability to recover from stalls and spins. 

      • Produces very light control forces (Sluggish Controls)

  • Control

    • CG location that is beyond the forward limit

      • May result in nose heaviness,

        • Making it difficult or impossible to flare for landing

    • CG location aft of the allowable range

      • May include extreme control difficulty, violent stall characteristics, and very light control forces which

      • Make it easy to overstress an aircraft inadvertently

  • Management

    • FAR 23.23

      • Requires establishment of the ranges of weights and CGs within which an aircraft may be operated safely.

      • Using approved AFM, TCDS (Type Certificate Data Sheet), or aircraft specifications

  • Terms and definitions

    • ARM

      • The horizontal distance in inches from the reference datum line to the CG of an item

    • Moment

      • The product of the weight of an item multiplied by its arm

    • Basic Empty Weight

      • The standard empty weight plus the weight of optional and special equipment that have been installed.

    • Zero Fuel weight

      • Weight of the plane without fuel

    • CG (Center of Gravity)

      • The point about which an aircraft would balance if it were possible to suspend it at that point

    • Datum plane

      • An imaginary vertical plane or line from which all measurements of arm are taken

  • Standard Weights

    • Gasoline- 6 lb/US gal

    • Jet A, Jet A-1 - 6.8 lb/US gal

    • Jet B - 6.5 lb/US gal

    • Oil - 7.5 lb/US gal

    • Water - 8.35 lb/US gal

  • Calculations (use POH)

    • Use example


  • Change in weight over Datum (Weight Shift)

  • Weight shift formula


  • Weight removal/add


  • Examples


Use of performance charts, tables, and other data in determining performance in various phases of flight.

Performance Charts & how to calculate

  • Takeoff

    • Normal

    • Short field

  • Climb 

  • Cruise

  • Landing

Effects of exceeding airplane limitations.

Show video of airplane running off runway

  • Higher takeoff speed

  • Longer takeoff run

  • Reduced rate and angle of climb

  • Lower maximum altitude

  • Shorter range

  • Reduced cruising speed

  • Reduced maneuverability

  • Higher stalling speed

  • Higher approach and landing speed

  • Longer landing roll

  • Excessive weight on the nose wheel or tail wheel


Effects of atmospheric conditions on performance.

  • Structure of the atmosphere

    • An envelope of air that surrounds the Earth and rests upon its surface

    • Column of Air above you

    • Air

      • Like a fluid

      • Fills any container

    • composed of 

      • 78 percent nitrogen,

      • 21 percent oxygen, and 

      • 1 percent other gases, such as argon or helium. 

      • Most of the oxygen is contained below 35,000 feet altitude.

  • Atmospheric pressure

    • helps to lift the aircraft

    • used for some instruments (Pitot Static System) 

    • Has MASS

      • 14.7 pounds per square inch (psi)

    • Up at altitude a reduction of:

      • 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

    • Standard Reference

      • 59 degrees Fahrenheit (°F) or 15 degrees Celsius (°C)

      • Surface pressure of 29.92 inches of mercury ("Hg) or 1013.2 millibars (mb).

    • Standard lapse rate

      • 2 °C per thousand feet

        • 3.5 °F

      • 1 "Hg per 1,000 feet of altitude gain to 10,000 feet.

  • Pressure altitude

    • Pressure altitude is the height above the standard datum plane (SDP)

    • To find pressure altitude

      • By setting the barometric scale of the altimeter to 29.92 "Hg and reading the indicated altitude

      • By applying a correction factor to the indicated altitude according to the reported “altimeter setting,”

      • Flight computer 

  • Density Altitude

    • Pressure altitude adjusted for non standard temperature

      • Give an example

  • Effects of pressure and density altitude





  • Temperature on density

Steam in a pot 




  • Performance

    • Straight and level

      • performance involve steady-state flight conditions and equilibrium of the aircraft.

    • Climb performance

      • Dependent upon the ability to produce either excess thrust or excess power

      • Power curve

    • Takeoff and landing

      • Runway surfaces

        • Go through NOTES section in POH

      • Water on runway

        • Hydroplaning

          • Like a car

      • Length of runway

  • Cross wind chart (notes section)

    • POH pg. 147/4-29 and ch 5

    • Use examples

      • RWY 07 wind 090 @ 10

      • RWY 18 wind 140 @ 15

      • RWY 34 wind 290 @ 25

Factors to be considered in determining that the required performance is within the airplane’s capabilities.

Example Situations

https://www.youtube.com/watch?v=FD1T97UqMMU&t=35s


Conclusion

Went over:

  1. Weight and Balance

  2. Structure of the atmosphere

  3. Pressure altitude

  4. Density altitude

  5. Performance

    1. Takeoff

    2. Cruise

    3. Landing 

  6. Wind direction Chart

(Questions to assess student)

Why is calculating weight and balance important?

Why do we calculate a CG?

What does the atmosphere consist of?

What affects aircraft performance?


HW: 

Go over the weight shift formula and look over the performance charts in the POH


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