US 12,410,757 B2
System and method of operating multi-engine system
Philippe Beauchesne-Martel, Brossard (CA); Gaetan De Lussy, Montréal (CA); Jeremie Hebert, Napierville (CA); and Daniel Coutu, Longueuil (CA)
Assigned to PRATT & WHITNEY CANADA CORP., Longueuil (CA)
Filed by PRATT & WHITNEY CANADA CORP., Longueuil (CA)
Filed on Dec. 2, 2021, as Appl. No. 17/540,570.
Prior Publication US 2023/0175437 A1, Jun. 8, 2023
Int. Cl. F02C 6/20 (2006.01); B64C 27/12 (2006.01); B64D 27/10 (2006.01); B64D 31/00 (2006.01); F02C 6/02 (2006.01)
CPC F02C 6/20 (2013.01) [B64C 27/12 (2013.01); B64D 27/10 (2013.01); B64D 31/00 (2013.01); F02C 6/02 (2013.01)] 19 Claims
OG exemplary drawing
 
10. A system for operating a multi-engine system of a helicopter, the multi-engine system having a first turboshaft engine having a first shaft, a second turboshaft engine having a second shaft, and a gearbox having a clutch system clutching at least one of the first shaft and the second shaft to a common load of the helicopter, the first and second shafts having a range of rotation speeds defined as a placarded zone, the system comprising:
a processing unit; and
a non-transitory storage medium having stored thereon program code executable by the processing unit for:
rotating the first and second shafts at a first idle rotation speed below the placarded zone when the first and second shafts are clutched to the load;
increasing a rotation speed of the first shaft from the first idle rotation speed to a flight rotation speed above the placarded zone;
unclutching the second shaft from the load during the increasing the rotation speed of the first shaft;
increasing a rotation speed of the second shaft to a second idle rotation speed when the second shaft is unclutched from the load, the second idle rotation speed above the placarded zone and below the flight rotation speed; and
maintaining the second shaft unclutched and maintaining the rotation speed of the second shaft to the second idle rotation speed until receiving a command to change an engine regime of the second turboshaft engine.
 
19. A method of operating a multi-engine system, the multi-engine system having a first engine having a first shaft, a second engine having a second shaft, and a gearbox having a clutch system clutching at least one of the first shaft and the second shaft to a load, the first and second shafts having a range of rotation speeds defined as a placarded zone, the method comprising:
rotating the first and second shafts at a first idle rotation speed below the placarded zone when the first and second shafts are clutched to the load;
increasing a rotation speed of the first shaft from the first idle rotation speed to a flight rotation speed above the placarded zone;
unclutching the second shaft from the load during said increasing the rotation speed of the first shaft;
increasing a rotation speed of the second shaft to a second idle rotation speed when the second shaft is unclutched from the load, the second idle rotation speed above the placarded zone and below the flight rotation speed; and
maintaining the second shaft unclutched and maintaining the rotation speed of the second shaft to the second idle rotation speed until receiving a command to change an engine regime of the second turboshaft engine.