Among the innovations hidden beneath the skin of Dassault’s Falcon 5X is a Thales-developed unit that will both electrically start the aircraft’s Snecma Silvercrest engines and generate power from them to supply aircraft systems. Believed to be the first time such devices have featured on a general aviation aircraft, the Thales TopStar suite on the new Falcon will include two starter-generators for the main engines, one for the auxiliary power unit (APU), three electronic regulators, three transformer rectifiers and a single electronic starter converter.

Similar to the integrated starter-generator devices that were first introduced into commercial airline use on Boeing’s more-electric 787, the Thales units transition between the two functions shortly after engine start. “The starting function begins with the starting box unit, which talks to the full-authority digital engine controller and, using the Snecma-developed engine laws as well as the latest temperature and altitude information, applies the appropriate torque,” says Thales Avionics Electrical Systems Chairman Guy Lefebvre. The unit switches to generator mode when it receives the signal from the start box unit. The variable speed, constant frequency, main engine starter provides up to 25 kVA for the Falcon 5X at a rated voltage of 115/230 Vac. The APU starter is similar but operates at a constant speed.

The Thales ensemble will be fitted to the first flight-test Silvercrest engine, which is due to fly in December on Snecma’s modified Gulfstream II flying testbed.