Ceiling climb tests

The variation in rate of climb with altitude and/or AUM in forward flight can be used to generate a range of climb schedules: for best rate of climb, for best angle of climb or minimum time to height. Consequently, it is often necessary to validate these schedules during a series of ceiling climbs. In addition to determining if the expected performance is realized, these tests are also used to establish whether any modification to the schedule is required for handling reasons.

Using a climb schedule, such as that shown in Fig. 3.35, a sustained climb is made to the maximum permitted altitude or the service ceiling (defined as ROC = 100 ft/ min), whichever is the lower. Data is recorded at periodic intervals based on height achieved and includes: [3]

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Fig. 3.34 Variation of climb performance with mass.

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Fig. 3.35 Derived climb schedule.

• Indicated rate of climb;

• Power parameter (torque or collective pitch);

• Engine speed and temperature;

• Rotor speed;

• Control positions;

• Vibration.

At low altitudes height intervals of 1000 ft are commonly used. The interval reduces to every 500 ft and then every 200 ft or even every 100 ft as the excess power diminishes.

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