{
  "$type": "site.standard.document",
  "description": "A power turbine speed control system (10) for a helicopter is disclosed which includes a) means for generating a power turbine speed signal (NF) and a power turbine shaft torque signal (QS) from a power turbine and rotor drive train; b) filtering means (40) for filtering the power turbine speed…",
  "path": "/patents/1074710",
  "publishedAt": "2005-08-31T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "B64C27/001",
    "GOODRICH PUMP & ENGINE CONTROL [US]"
  ],
  "textContent": "A power turbine speed control system (10) for a helicopter is disclosed which includes a) means for generating a power turbine speed signal (NF) and a power turbine shaft torque signal (QS) from a power turbine and rotor drive train; b) filtering means (40) for filtering the power turbine speed signal (NF) by effectuating a rapid attenuation of main and tail rotor torsional frequencies in the power turbine speed signal (NF) without compromising phase at low frequencies; and c) damping means (14) for actively damping main and tail rotor torsional frequencies in the power turbine shaft torque signal (QS).",
  "title": "Engine control system"
}