Williams Keeps Quiet About Engine Features
FJ44-4A turbofan to provide passive thrust vectoring and APU mode

Pilatus and Williams International have been touting some features–passive thrust vectoring and quiet power mode–of the FJ44-4A turbofan on the PC-24 but the engine manufacturer is scarce on details. The so-called Exact passive thrust vectoring system uses “a proprietary fluid dynamic scheme,” Matt Huff, Williams’ business development vice president, told AIN. The thrust vector from the exhaust nozzle varies as a function of engine operating conditions–power setting, exhaust gas temperature, Mach number and altitude. As the benefit can be seen in performance and efficiency, “it adds much less weight than what it typically saves,” Huff asserted. The technology is said to have been validated through flight tests several years ago.