NORMAL TAKEOFF FROM A HOVER

A Normal Takeoff from a Hover is an orderly transition to forward flight and is executed to increase altitude safely and expiditiously. During the takeoff, fly a profile that avoids the hazardous areas of the height-velocity diagram for that particular helicopter.

Technique

Refer to the figure below (Position 1). Bring the helicopter to a hover and make a performance check which includes power, balance and flight controls. The power check should include an evaluation of the amount of excess power available; that is, the difference between the power being used to hover and the power available at the existing altitude and temperature conditions. The balance condition of the helicopter is indicated by the position of the cyclic when maintaining a stationary hover. Wind will necessitate some cyclic deflection, but there should not be an extreme deviation from neutral. Flight controls must move freely and the helicopter should respond normally. (You may have already checked them during your run up, but make a last check prior to taking off). Then visually clear the area all around.

Start the helicopter moving by smoothly and slowly easing the cyclic forward (Position 2). As the helicopter starts to move forward, increase the collective as necessary to prevent the helicopter from sinking and adjust the throttle to maintain rotor RPM. The increase in power requires an increase in the proper antitorque pedal input to maintain your heading. Maintain a straight takeoff path (if available) throughout the takeoff. As you accelerate through effective translational lift (ETL) (Position 3) the helicopter begins to climb and the noce tends to pitch up due to increased lift. At this point adjust the collective to obtain normal climb power and apply enough forward cyclic to overcome the tendancy of the nose to pitch up. At (Position 4), hold an attitude that allows a smooth accelleraation toward climbing airspeed and a commensurate gain in altitude so that the takeoff profile avoids the hazardous areas of the height-velocity diagram for that particular helicopter. As airspeed increases (Position 5), the streamlining of the fuselage reduces engine torque effect, requiring a reduction in antitorque pedal pressure. as the helicopter continues to climb and accelerate to its best rate of climb, apply aft cyclic pressure to raise the nose smoothly to the normal climb attitude.

Common Errors

Failing to use sufficient collective pitch to prevent a loss of altitude prior to attaining translational lift.
Adding power too rapidly at the beginning of the transition from hovering to forward flight without forward cyclic comphensation, causing the helicopter to gain excessive altitude before acquiring airspeed.
assuming an extreme nose-down attitude near the surface in the transition from hovering to forward flight.
Failing to maintain a desired ground track over the surface.
Failing to maintain proper airspeed during the climb.
Failing to maintaim proper rotor RPM.

I deviate from the manual in terms of a straight ground track, several departures I have at FXE are not straight out departures, requiring a turn at 300 feet AGL. The point is to maintain the ground track desired while transitioning to forward flight from the hover.


NORMAL TAKEOFF FROM THE SURFACE

A Normal Takeoff from the Surface is used to move the helicopter from a position on the surface into effective translational lift (ETL) and a normal climb using a minimum amount of power. If the surface is dusty or covered with loose snow, this technique provides the most favorable visability conditions and reduces the possibility of debris being ingested by the engine.

Technique

Place the helicopter in a stationary position on the surface. Lower the collective to the full down position, and reduce the rotor RPM to below operating RPM. Visually clear the area and select terrain features, or other objects, to aid in maintaining the desired ground track during takeoff and climb out. Increase the throttle to the proper RPM and raise the collective slowly until the helicopter is light on the skids. Hesitate momentarily and adjust the cyclic and antitorque pedals as necessary to prevent any surface movement. Continue to apply upward collective, as as the helicopter breaks ground, use the cyclic as necessary, to begin forward movement as altitude is gained. continue to accelerate, as as effectice translational lift (ETL) is attained, the helicopter begins to climb. Adjust attitude and power, if necessary, to climb in the same manner as a takeoff from a hover.

Common Errors

Departing the surface in an attitude that is too nose-low. This situation requires the use of excessive power to climb.
Using excessive power combined with alevel attitude, which causes a vertical climb.
Too abrupt application of the collective when departing the surface, possibly drooping RPM, and causing heading control errors.

The takeoff from the surface is neither a running takeoff, or a max performance one. The trick is to liftoff and then establish the normal acceleration to the climb, without losing altitude, or gaining excessive altitude before you have the airspeed for that altitude referring to the height-velocity diagram for the particular helicopter.


CROSSWIND CONSIDERATIONS DURING TAKEOFFS

If the takeoff is made during crosswind conditions, the helicopter is flown in a slip during the early stages of the maneuver. The cyclic is held into the wind a sufficient amount to maintain the desired ground track for the takeoff.

The heading is maintained with the use of the antitorque pedals. In other words, the rotor is tilted into the wind so that the sideward movement of the helicopter is just enough to counteract the crosswind effect.

To prevent the nose from turning in the direction of the rotor tilt, it is necessary to increase antitorque pedal pressure on the side opposite the rotor tilt.

After approximately 50 feet of altitude is gained, make a coordinated turn into the wind to maintain the desired ground track while on departure.

This is called crabbing into the wind. The stronger the crosswind, the larger the crab angle you will need to stay on the desired track.


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Page Last Updated on: Nov-06-2017