Angle of Climb

A figure like the bottom part of Figure 4.48 can also be used to determine the maximum angle of climb, which might be of interest in clearing an obstacle in the flight path. In this case the maximum angle is 90° when both engines are running, since the helicopter an climb vertically. With one engine, however, it annot even hover, but it an climb at 1,100 ft/min at 48 knots, which gives a climb angle of

12.7 degrees. A similar analysis can be made when the gross weight or the altitude is too high for hover out of ground effect with two engines.

The minimum time to climb to a given altitude an be calculated using the maximum rates of climb on Figure 4.49 to determine the time required to climb in 1,000-ft increments. The summation of this process is shown on Figure 4.50. Knowing the speed corresponding to the climb rates makes it possible to find the distance required to climb. These values will later be useful in doing mission analyses.

Two world records for time-to-climb are spotted in Figure 4.50. These were set in 1972 with a Sikorsky CH-54B and were still valid in 1985.