Figure 24-1: No-hover takeoff
1. Ensure the RPM is at maximum takeoff setting, and complete pre-takeoff checks;
2. take a careful lookout all around;
3. smoothly apply collective in a single movement to initiate a vertical climb, co-ordinate pedal to keep straight, use cyclic to set the climb attitude as the aircraft passes normal hover height; and
4. when clear of obscuring phenomena adjust controls for normal climb.
As this type of takeoff is not preceded by a hover-check, you have to be sure that the helicopter weight and balance are within limits, and that sufficient power is available for the intended departure.
CUSHION TAKEOFF.
This type of departure is economical in power required, since it involves making maximum use of the ground effect until translational lift is acquired (Figure 24-2). However, a relatively flat area, free of obstacles, is required for this technique. It is useful if the helicopter is heavily loaded and it is not possible to perform an into-wind transition.
Figure 24-2: Cushion takeoff
1. Perform pre-takeoff checks, and carry out a power check at the low hover;
2. look out;
3. initiate slow forward movement with cyclic and use collective to prevent any tendency to sink;
4. continue a gradual acceleration staying in maximum ground effect; and
5. at approximately 30 - 40 kts, select climb attitude and power.
It is most important to use gentle and smooth control movements to get the maximum benefit from this type of takeoff. The take-off profile is extremely flat initially, so it is essential to look out and keep a close watch on the ground to maintain a safe clearance.
TOWERING TAKEOFF.
This type of takeoff is employed when there are obstacles in the take-off path but the area does not require a vertical ascent. More power will be required but you should use only the amount that is necessary to successfully depart over the obstacle. A good method to ensure obstacle clearance is to maintain the same relative vertical distance between the obstacle and the rotor disc, as viewed from the cockpit.
1. Perform pre-takeoff checks and carry out a power check at the low hover;
2. look out, and select a lateral marker in order to climb vertically initially;
3. from the low hover smoothly apply collective, and climb vertically initially, keep the disc the same vertical distance above the obstacle;
4. when your eyes are level with the top of the obstacle, and still indicating a climb, introduce forward flight; and
5. use power only as required and when clear of the obstacle adjust to normal climb configuration.
6. Using only the power required, as opposed to a vertical departure or “charging” the obstacle, will give you a reserve in the event you have to abort the takeoff. The obstacle can shield the helicopter from the wind, and as you climb you may find you will “pick up” the wind, which will assist the departure. In some wind conditions, you could also encounter turbulence in the lee of the obstacle. This type of takeoff is used for night flying.
VERTICAL TAKEOFF
Figure 24-3: Vertical Takeoff
This technique is used when there is insufficient space in the area to perform the methods previously described. The conditions and obstacle height will dictate the power required but much higher power settings are normally the case (Figure 24-3).
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