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Old 26th April 2011 | 18:58
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delta3
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From: Belgium
Example of R44 dynamics

Levi

A very simple example :

R44, 2 POB, 140 liters, steady 50 feet hover, ISA.

Cyclic is at -2.15 degrees during this hover.
Pilot applies a step input to cyclic bringing and holding it 0.5 degree forward, so at -1.62 degrees.




Results

1. Not in graph: rotor reacts immediately <0.2 sec
2. First two seconds, no alt change, very little speed changes, just a pitching down.
3. As speed picks up, heli starts descending at 500 f/min, but pitching down is halted
4. After passing TL-point a very progressive blow back occurs that makes to heli pitch up brutally, putting nose right up in the sky.

A Pilot (at least I hope) would of course not fly like this and would apply further forward cyclic to "control" the heli. But it gives you a rough idea about time constants. (Graph starts just at the moment of applying the forward cyclic, an auto-pilot feature of the simulator controlled lateral cyclic and tail-rotor, collective was held steady on 9.5 degrees)

d3
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