Beechcraft BE76 Duchess - Page 7

Certified Flyers II
Duchess Multi-Engine Study Guide
6
EFFECT ON
Vmc
PERFORMANCE
Power Increase
Up- more yaw
Up- more power
Temp Increase
Down- less dense, less power, less yaw
Down- less dense, less power
Pressure Decrease
Down- less dense, less power, less yaw
Down- less dense, less power
Density Altitude
Increase
Down- less dense, less power, less yaw
Down- less dense, less power
Bank Angle- 0 bank-
no turn
Up- sideslip plane- less AOA on rudder
because of sideslip airflow- less rudder
effectiveness- more rudder needed
Down- more drag- slipping
Zero Sideslip- 2-3
bank- no turn
Middle- Use horizontal lift to stop turn- not
slipping- more rudder effectiveness
Up- less drag- zero slip
Bank Angle- 5 bank-
no turn
Down- plane turning toward good engine +
rudder used to stop turn = slip toward good
engine- high AOA on rudder
Down- more drag- slipping
Windmilling Propeller
Up- more drag, more yaw
Down- more drag
Feathered Propeller
Down- less drag, less yaw
Up- less drag
Aft CG
Up- less distance between rudder and CG-
less rudder effectiveness
Up- less tail down force required
less induced drag; Down- smaller
arm on controls, less control
effectiveness
Heavier Weight
Down- more lift needed in level flight- more
horizontal lift available during turn- helps
prevent turn
Down- more weight, more power
required
Flaps Down
Down- more induced drag from good
engine side prevents yaw towards dead
engine
Down- more airflow over flap
causes greater drag, increased
yaw, increased roll, requiring more
aileron to stop, creating more
adverse yaw= more induced drag
Gear Down
Depends on location of CG to gear and
direction of travel (Vmc down, keel effect)
Down- more parasitic drag
Critical Engine Fails
Up- P-factor, Accelerated Slipstream,
Torque makes yaw worst
Down- larger control inputs
In Ground Effect
Up- less drag- more thrust available- more
yaw
Up- less drag