Climbs. For any power setting and load condition, there is only one airspeed which will give the most efficient rate of climb. To determine this, you should consult the climb data for the type helicopter being flown. The technique varies according to airspeed on entry and the type of climb (constant airspeed or constant rate) desired.
Entries. To enter a constant airspeed climb from cruise airspeed (if climb speed is lower than cruise speed), simultaneously increase torque to the climb power setting and adjust pitch attitude to the approximate climb attitude. The increase in power causes the helicopter to start climbing and only very slight back cyclic pressure need be applied to complete the change from level to climb attitude. The attitude indicator should be used to accomplish the pitch attitude change. If the transition from level flight to a climb is smooth, the vertical-speed indicator will show an immediate upward trend and will stop at a rate appropriate to the stabilized airspeed and attitude. Primary and supporting instruments for climb entry are illustrated in Figure 6-8.
When the helicopter stabilizes on a constant airspeed and attitude,
the airspeed indicator becomes primary for pitch. The torque meter continues
to be primary for power and should be monitored closely to determine that
the proper climb power setting is being maintained. Primary and supporting
instruments for a stabilized constant airspeed climb are shown in Figure
If cruise and climb airspeeds are the same, the climb pitch attitude, shown by the attitude indicator, will be nearly the same as the cruise pitch attitude.
The technique and procedures for entering a constant rate climb are very similar to those previously described for a constant airspeed climb. For training purposes, a rate climb is entered from climb airspeed. The rate used will be the one that is appropriate for the particular helicopter flown. Normally, in helicopters with low rates of climb, 500 feet per minute is appropriate. In helicopters capable of high climb rates, use a rate of 1,000 feet per minute.
Figure 6-8. Climb entry - constant airspeed climb.
Figure 6-9. Stabilized climb - constant airspeed.
To enter a rate climb, increase torque to the approximate setting for the desired rate. As power is applied, the airspeed indicator is primary for pitch until the vertical speed approaches the desired rate. At this time, the vertical-speed indicator becomes primary for pitch. Change pitch attitude by reference to the attitude indicator to maintain the desired vertical speed. When the vertical-speed indicator becomes primary for pitch, the airspeed indicator becomes primary for power. Primary and supporting instruments for a stabilized constant rate climb are illustrated in Fig. 6-10. Adjust torque to maintain desired airspeed. Pitch attitude and power corrections should be closely coordinated. To illustrate this, if the vertical speed is correct, but the airspeed is low, add power. As the power is increased, it may be necessary to lower the pitch attitude slightly to avoid increasing the vertical rate. Adjust the pitch attitude smoothly to avoid overcontrolling. Small power corrections (approximately 5 percent torque) usually will be sufficient to bring the airspeed back to the desired indication.
Leveling off. The level-off from a constant airspeed climb must be started before reaching the desired altitude. Although the amount of lead varies with the helicopter and pilot technique, the most important factor is vertical speed. Normally, the lead for each 500 feet per minute rate of climb is 50 feet. When the proper altitude lead is reached, the altimeter becomes primary for pitch. Adjust the pitch attitude to level flight attitude for that airspeed. Cross-check the altimeter and vertical speed to determine whether level flight has been attained at the desired altitude. To level off at cruise airspeed (if this speed is higher than climb airspeed), leave the torque at climb power setting until the airspeed approaches cruise airspeed, then reduce torque to cruise power setting.
The level off from a constant rate climb is accomplished in the
same manner as the level off from a constant airspeed climb.
Descents. A descent may be performed at any normal airspeed the helicopter is capable of, but the airspeed must be determined prior to entry. The technique is determined by type of descent (constant airspeed or constant rate).
Entries. If your airspeed is higher than descending airspeed and you wish to make a constant airspeed descent at descending airspeed, reduce torque to the descending power setting and maintain a constant altitude. When you approach the descending airspeed, the airspeed indicator becomes primary for pitch and the torque meter continues to be primary for power. The helicopter will begin to descend as the airspeed is held constant. For a constant rate descent, reduce the torque to the approximate setting for the desired rate. If the descent is started at descending airspeed, the airspeed indicator is primary for pitch until the vertical speed approaches the desired rate. At this time, the vertical-speed indicator becomes primary for pitch and the airspeed indicator becomes primary for power. Coordinate power and pitch attitude control as was described earlier for constant rate climbs.
Figure 6-10. Stabilized climb - constant rate.
Leveling off. The level off from a constant airspeed descent may
be made at descending airspeed or at cruise airspeed (if this is higher
than descending airspeed). As in a climb level off, the altitude lead depends
on rate of descent and control technique. For a level off at descending
airspeed, this lead should be approximately 50 feet for each 500 feet per
minute rate of descent. At the altitude lead, simultaneously advance the
torque to the setting necessary to maintain descending airspeed in level
flight. At this point, the altimeter becomes primary for pitch and the
airspeed indicator becomes primary for power.
To level off at an airspeed higher than descending airspeed, increase the torque approximately 100 to 150 feet prior to reaching the desired altitude. The power setting should be that which is necessary to maintain the desired airspeed in level flight. Hold the vertical speed constant until approximately 50 feet above the desired altitude. At this point, the altimeter becomes primary for pitch and the airspeed indicator becomes primary for power. The level off from a constant rate descent should be accomplished in the same manner as the level off from a constant airspeed descent.
Common Errors During Straight Climbs and Descents.
1. Failure to maintain heading.
2. Improper use of power.
3. Poor control of pitch attitude.
4. Failure to maintain proper pedal trim.
5. Failure to level off on desired attitude.