Williams Selected For SyberJet SJ36

LAS VEGAS—SyberJet Aircraft has selected the Williams International FJ44-4A as the powerplant for its newly unveiled SJ36 light jet.

Rated at 3,620 lb.-thrust, the engine is already used by Textron’s Cessna CitationJet CJ4 and Pilatus PC-24, and for the SJ36 will give the nine-seat aircraft a targeted cruise speed of Mach 0.88. SyberJet’s SJ36 is scheduled to make its first flight with certification and first deliveries in 2032.

The launch of the FJ44-4-powered SJ36 re-establishes SyberJet’s link with Williams, which provided the earlier FJ44-2 for the long-abandoned SJ30 predecessor program. Phoenix-based SyberJet says that with a maximum takeoff weight of 18,500 lb., the combined thrust of the two FJ44s will give the SJ36 a 38.9% thrust-to-weight ratio. The company adds that with a range of 3,000 nm., the SJ36 “is expected to become the fastest and longest-range light jet in the world.”

SyberJet’s engine selection was announced here at NBAA-BACE, where Williams also revealed a rare glimpse of the -4A passive-thrust-deflecting nozzle design developed for the PC-24 application.

Normally enclosed and hidden from view by the nacelle, the exhaust nozzle incorporates a curved upper ramp that generates a Coandă effect to keep the exhaust airflow attached to the nozzle. The flow sticks to the surface due to viscosity and entrains surrounding airflow, creating a low-pressure area that pulls the jet toward the surface. The ramp directs the flow upwards by around 3 deg. at slow speeds, producing a tail-down thrust component on takeoff, which aids aircraft rotation. At higher speeds, the flow straightens with zero drag penalty.