The graph on the right shows the tail rotor pitch and the resultant turn-rate of the helicopter over a 15 second period.
These graphs are useful to determine how hard the servo motors are being worked. The system is operating in heading-hold mode. The Z rate shown is barely visible to the pilot as the actual angle is being held to within a few degrees.
The real-time telemetry data is a very useful feature of the CARVEC system. It provides the ability to log most of the system parameters in real time at up to 60Hz, including:
The telemetry data is also invaluable for setting up manual-backup control features, such as the transmitter pitch/throttle curve and revolution mixing for manual tail-rotor control. The helicopter can be flown in the automatic modes, then the relationship between the controls determined from the telemetry logs. The Tx can then be set to mimic these values.
The data is logged to a normal ASCII file which can be easily imported into an application such as microsoft excel. A few graphs of actual telemetry data are shown below as examples.
This graph shows the collective pitch and throttle for the Sceadu 50 machine during one of the test flights.
The graph is 15 seconds of flight. The machine is hovering at about 5.5 degrees collective and 55% throttle. In previous runs where the engine was not tuned correctly, it needed around 70% throttle.
The telemetry data can be checked from time to time to look for changes in performance. Any differences often indicate something needs attention - sometimes before it is actually noticed whilst flying.
This final graph is a situation where the main unit is detecting vibration in the roll axis - again over a 15 second period.
The telemetry can be used to determine the effect of various attempts to correct the vibration such as adding weight to one of the blades, or a different rotor RPM.
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