Mass and Balance | FP&P Flashcards
State the 6 effects of a too far forward CoG
- Increased drag and fuel consumption. Both range and endurance reduce
- Increased longitudinal stability requires greater control forces. There will be greater difficulty in pitching the nose up, controllability decreases.
- Due to increases tail down force more lift is required from the mainplane resulting in a higher stall speed.
- It will be more difficult to rotate during take-off, the higher speed required for elevator effectiveness results in a longer take-off roll.
- Climb performance is reduced due to the nose down tendency.
- Landing difficulties due to the nose heavy condition accompanied by reduces elevator effectiveness caused by low speed.
State the 5 effects of a too far aft CoG
- Tail heavy condition may result in early rotation during take-off. Less elevator deflection required could lead to over-rotation.
- Reduced down force from the tail reduces drag, requiring less thrust resulting in increased range and endurance.
- Spin recovery ability is reduced with added danger of a flat spin.
- In the case of a single engined airplane the glide angle may be difficult to maintain as a result of the nose tending to pitch up.
- Longitudinal stability reduces along with controllability. Excessive elevator control input may over-stress the airplane.
Define the Aircraft Empty Weight(AEW)
The Aircraft Empty Weight is the measured weight of an aircraft including fixed operating equipment, fixed ballast and hydraulic fluid.
Define The Basic Empty Weight(BEW)
BEW is the Aircraft Empty weight plus full oil and unusable fuel.
Define The Operating Empty Weight(OEW)
The OEW is the BEW plus the crew, their baggage and in-flight rations.
Define Zero Fuel Weight(ZFW)
The ZFW is the OEW plus passengers, baggage and cargo(collectively called payload). Usable is not included.
Define Ramp Weight
The ramp weight is ZFW plus usable fuel.
Define Take-off weight
Take-off weight is the weight of the aircraft at lift-off from the runway. i.e, The ramp weight minus taxi fuel.
Define Landing Weight
The landing weight is the weight of the aircraft at touchdown. I.e, Take-off weight minus trip fuel.
Define MTOW
MTOW, or Maximum Take-Off Weight, is the maximum weight allowed at take-off.
Define MZFW
MZFW, or Maximum Zero Fuel Weight, is the maximum allowable aircraft weight before usable fuel is added.
Define MRW
MRW, or Maximum Ramp Weight, is the maximum weight permitted prior to taxying. It may exceed the MTOW by the taxi fuel allowance.
Define MLW
MLW, or Maximum Landing Weight, is the maximum allowable weight for landing. For many light aircraft the MLW equals the MTOW. For other aircraft the MLW is less than the MTOW. In this case the fuel burn-off must be sufficient to reduce the weight below the MLW prior to landing. In an emergency, fuel may have to be dumped.
Finding the MAC percentage:
CG is 280” aft of the datum, the MAC is 105” and the LEMAC 235”. Define the process of calculating the percentage of MAC
CG 280” - LEMAC 235” = 45”
45 divided by MAC 105” x 100 = 42,8% MAC
Finding the MAC percentage:
CG 300”, LEMAC 230”, MAC 120”. Define the process of calculating the MAC as a percentage
CG 300” - LEMAC 230” = 70
70 divided by MAC 120” x 100 = 58%
