Mast torque - percent Det mast torque - percent Density altitude - feet Pressure altitude - feet Engine torque percent 14000 12000 10000 8000 6000 4000 2000 0 100 90 80 70 60 50 40 100 90 80 70 60 50 40 100 90 80 70 60 50 40 -5000 0 5000 10000 15000 3 5 10 15 50 (OGE) Skid height feet 5500 - 60 FAT °C 40 - 20 0 20 + 40 60 5250 5000 4750 4500 4250 4000 3750 3500 3250 3000 Gross weight pounds A B C D 66% Figure 7-6.  Torque required for cruise or level flight.  speed is normally used during the climb after all obstacles  have been cleared and is usually maintained until reaching  cruise altitude. Rate of climb must not be confused with angle  of climb. Angle of climb is a function of altitude gained over  a given distance. The V$_{Y }$results in the highest climb rate, but  not the steepest climb angle, and may not be sufficient to clear  obstructions. The best angle of climb speed (V$_{X}$) depends upon  the power available. If there is a surplus of power available,  Most of the factors affecting hover and takeoff performance  also affect climb performance. In addition, turbulent air, pilot  techniques, and overall condition of the helicopter can cause  climb performance to vary. A helicopter flown at the best rate-of-climb speed (V$_{Y}$) obtains  the greatest gain in altitude over a given period of time. This  7-7