How do you do a VMC demo?
How to Perform a VMC Demonstration
- Adjust the mixture controls as required.
- Set the propeller controls full forward.
- Retract the landing gear.
- Set the flaps to the normal takeoff setting.
- Set the trim for takeoff and do not readjust it during the maneuver.
- Set the cowl flaps for takeoff.
- Establish a normal cruise speed.
What is the purpose of a VMC demonstration?
The point of the Vmc Demonstration is to recognize and recover from a loss of directional control with the critical engine inop.
How is VMC determined?
VMC is determined with the critical engine propeller windmilling in the takeoff position, unless the engine is equipped with an autofeather system.
What is a VMC roll?
The Vmc roll, specifically, is a rapid roll (not yaw) below Vmc. It occurs primarily because a thrusting engine located on a wing decreases the stall speed significantly. Therefore, as airspeed decreases, a moment occurs when the wing with non-thrusting engine stalls, while the other wing continues to produce lift.
Do flaps increase Vmc?
So Vmc will be lower with flaps extended, and higher with flaps retracted (the take-off position for this aircraft). Cowl flaps in the open position will increase drag on the aircraft, and may also provide a very slight weathervaning/stabilizing effect on the yawing motion.
What factors affect Vmc?
Factors That Affect Vmc Speed
- Standard Day at Sea Level.
- Most Unfavorable Weight.
- Aft CG.
- Critical Engine Windmilling.
- Flaps Takeoff Position/Landing Gear Up.
- Up to 5 Degrees Bank.
- Max Power in Operating Engine.
Why do flaps decrease Vmc?
With the cowl flaps open the operating engine’s prop will push air into the cowl flaps resulting in increased drag. Increased drag on the operating engine decreases Vmc since it assists in counteracting the yaw toward the dead engine.
What are the 9 factors of VMC?
Factors of Vmc
- Maximum take-off Power at Sea Level. (Density Altitude is at Sea Level) Increase.
- At Gross Weight. Decrease. Decrease.
- Most Adverse CG (usually Aft) Increase. Increase.
- Gear Up. Increase.
- Take-off Flaps. Increase.
- Take-off Trim. Decrease.
- Take-off Cowl Flaps. Decrease.
- Windmilling Propeller on Critical Engine. Increase.
Do we want VMC to be higher or lower?
We want to maintain control at the slowest possible speed, so A LOWER Vmc IS GOOD and A HIGHER Vmc IS BAD. Anything increasing the force to the dead engine will increase Vmc, and vice versa. Anything increasing the amount of force the rudder can produce will decrease Vmc, and vice versa.